The new urban politics as a politics of carbon control.

PubMed

Jonas, Andrew E G; Gibbs, David; While, Aidan

2011-01-01

The new urban politics (NUP) literature has helped to draw attention to a new generation of entrepreneurial urban regimes involved in the competition to attract investment to cities. Interurban competition often had negative environmental consequences for the urban living place. Yet knowledge of the environment was not very central to understanding the NUP. Entrepreneurial urban regimes today are struggling to deal with climate change and reductions in greenhouse gas emissions. Carbon reduction strategies could have profound implications for interurban competition and the politics of urban development. This paper explores the rise of a distinctive low-carbon urban polity—carbon control—and examines its potential ramifications for a new environmental politics of urban development (NEPUD). The NEPUD signals the growing centrality of carbon control in discourses, strategies and struggles around urban development. Using examples from cities in the US and Europe, the paper examines how these new environmental policy considerations are being mainstreamed in urban development politics. Alongside competitiveness, the management of carbon emissions represents a new yet at the same time contestable mode of calculation in urban governance.

78 FR 44112 - California State Motor Vehicle Pollution Control Standards; Urban Buses; Request for Waiver of...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-23

... Board (CARB) its request for a waiver of preemption for emission standards and related test procedures... standards and test procedures for heavy-duty urban bus engines and vehicles. The 2000 rulemaking included... to emission standards and test procedures resulting from these five sets of amendments were codified...

High reduction of ozone and particulate matter during the 2016 G-20 summit in Hangzhou by forced emission controls of industry and traffic

EPA Science Inventory

Many regions in China experience air pollution episodes because of the rapid urbanization and industrialization over the past decades. Here we analyzed the effect of emission controls implemented during the G-20 2016 Hangzhou summit on air quality. Emission controls included a fo...

Nitrous oxide emissions in the Shanghai river network: implications for the effects of urban sewage and IPCC methodology.

PubMed

Yu, Zhongjie; Deng, Huanguang; Wang, Dongqi; Ye, Mingwu; Tan, Yongjie; Li, Yangjie; Chen, Zhenlou; Xu, Shiyuan

2013-10-01

Global nitrogen (N) enrichment has resulted in increased nitrous oxide (N(2)O) emission that greatly contributes to climate change and stratospheric ozone destruction, but little is known about the N(2)O emissions from urban river networks receiving anthropogenic N inputs. We examined N(2)O saturation and emission in the Shanghai city river network, covering 6300 km(2), over 27 months. The overall mean saturation and emission from 87 locations was 770% and 1.91 mg N(2)O-N m(-2) d(-1), respectively. Nitrous oxide (N(2)O) saturation did not exhibit a clear seasonality, but the temporal pattern was co-regulated by both water temperature and N loadings. Rivers draining through urban and suburban areas receiving more sewage N inputs had higher N(2)O saturation and emission than those in rural areas. Regression analysis indicated that water ammonium (NH(4)(+)) and dissolved oxygen (DO) level had great control on N(2)O production and were better predictors of N(2)O emission in urban watershed. About 0.29 Gg N(2)O-N yr(-1) N(2)O was emitted from the Shanghai river network annually, which was about 131% of IPCC's prediction using default emission values. Given the rapid progress of global urbanization, more study efforts, particularly on nitrification and its N(2)O yielding, are needed to better quantify the role of urban rivers in global riverine N(2)O emission. © 2013 John Wiley & Sons Ltd.

Emissions performance of abatement technologies over the proposed EEC extra-urban driving cycle

DOE Office of Scientific and Technical Information (OSTI.GOV)

VanBeckhoven, L.C.; Rijkeboer, R.C.

1989-01-01

The definition of what is likely to be the new EEC extra-urban cycle has made it possible to determine the emission characteristics of cars fitted with different emissions control equipment. Central to the evaluation program were three versions of experimental lean and dilute burn engines compared with engine modifications and open and closed loop three-way catalyst systems. This paper describes the evaluation program and evaluates its results.

Effects of urban density on carbon dioxide exchanges: Observations of dense urban, suburban and woodland areas of southern England.

PubMed

Ward, H C; Kotthaus, S; Grimmond, C S B; Bjorkegren, A; Wilkinson, M; Morrison, W T J; Evans, J G; Morison, J I L; Iamarino, M

2015-03-01

Anthropogenic and biogenic controls on the surface-atmosphere exchange of CO2 are explored for three different environments. Similarities are seen between suburban and woodland sites during summer, when photosynthesis and respiration determine the diurnal pattern of the CO2 flux. In winter, emissions from human activities dominate urban and suburban fluxes; building emissions increase during cold weather, while traffic is a major component of CO2 emissions all year round. Observed CO2 fluxes reflect diurnal traffic patterns (busy throughout the day (urban); rush-hour peaks (suburban)) and vary between working days and non-working days, except at the woodland site. Suburban vegetation offsets some anthropogenic emissions, but 24-h CO2 fluxes are usually positive even during summer. Observations are compared to estimated emissions from simple models and inventories. Annual CO2 exchanges are significantly different between sites, demonstrating the impacts of increasing urban density (and decreasing vegetation fraction) on the CO2 flux to the atmosphere. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Computer-oriented emissions inventory procedure for urban and industrial sources

DOE Office of Scientific and Technical Information (OSTI.GOV)

Runca, E.; Zannetti, P.; Melli, P.

1978-06-01

A knowledge of the rate of emission of atmospheric pollutants is essential for the enforcement of air quality control policies. A computer-oriented emission inventory procedure has been developed and applied to Venice, Italy. By using optically readable forms this procedure avoids many of the errors inherent in the transcription and punching steps typical of approaches applied so far. Moreover, this procedure allows an easy updating of the inventory. Emission patterns of SO/sub 2/ in the area of Venice showed that the total urban emissions were about 6% of those emitted by industrial sources.

Ozone changes in response to the heavy-duty diesel truck control in the Pearl River Delta

NASA Astrophysics Data System (ADS)

Yu, Xin; Yuan, Zibing; Fung, J. C. H.; Xue, Jian; Li, Ying; Zheng, Junyu; Lau, A. K. H.

2014-05-01

In recent years, restricting heavy-duty diesel trucks from driving within urban areas during the daytime is implemented in major PRD cities (e.g. Guangzhou and Shenzhen). Potential effects of this traffic control policy on spatial and temporal variations of O3 concentrations are examined by CMAQ model system. Temporal profiles of mobile source emissions are modified to reflect the emission characteristics after the control. Our results show that: (1) with the updated mobile emission profile, there is a notable improvement in O3 simulation performance for urban sites, with reductions in both the nighttime O3 overestimation (up to 25 ppb) and the daytime underestimation on O3 peak values (up to 20 ppb); (2) although the control policies are only applied in urban locations, their effects may extend to much larger downwind areas. The results from this study provide basic information that is useful in understanding the effects of mobile control policies on ambient O3 in highly developing regions of China where similar strategies have been widely implemented.

Heat Waves, Urban Vegetation, and Air Pollution

NASA Astrophysics Data System (ADS)

Churkina, G.; Grote, R.; Butler, T. M.

2014-12-01

Fast-track programs to plant millions of trees in cities around the world aim at the reduction of summer temperatures, increase carbon storage, storm water control, provision of space for recreation, as well as poverty alleviation. Although these multiple benefits speak positively for urban greening programs, the programs do not take into account how close human and natural systems are coupled in urban areas. Elevated temperatures together with anthropogenic emissions of air and water pollutants distinguish the urban system. Urban and sub-urban vegetation responds to ambient changes and reacts with pollutants. Neglecting the existence of this coupling may lead to unforeseen drawbacks of urban greening programs. The potential for emissions from urban vegetation combined with anthropogenic emissions to produce ozone has long been recognized. This potential increases under rising temperatures. Here we investigate how global change induced heat waves affect emissions of volatile organic compounds (VOC) from urban vegetation and corresponding ground-level ozone levels. We also quantify other ecosystem services provided by urban vegetation (e.g., cooling and carbon storage) and their sensitivity to climate change. In this study we use Weather Research and Forecasting Model with coupled atmospheric chemistry (WRF-CHEM) to quantify these feedbacks in Berlin, Germany during the heat waves in 2003 and 2006. We highlight the importance of the vegetation for urban areas under changing climate and discuss associated tradeoffs.

Reducing Urban Greenhouse Gas Footprints.

PubMed

Pichler, Peter-Paul; Zwickel, Timm; Chavez, Abel; Kretschmer, Tino; Seddon, Jessica; Weisz, Helga

2017-11-07

Cities are economically open systems that depend on goods and services imported from national and global markets to satisfy their material and energy requirements. Greenhouse Gas (GHG) footprints are thus a highly relevant metric for urban climate change mitigation since they not only include direct emissions from urban consumption activities, but also upstream emissions, i.e. emissions that occur along the global production chain of the goods and services purchased by local consumers. This complementary approach to territorially-focused emission accounting has added critical nuance to the debate on climate change mitigation by highlighting the responsibility of consumers in a globalized economy. Yet, city officials are largely either unaware of their upstream emissions or doubtful about their ability to count and control them. This study provides the first internationally comparable GHG footprints for four cities (Berlin, Delhi NCT, Mexico City, and New York metropolitan area) applying a consistent method that can be extended to other global cities using available data. We show that upstream emissions from urban household consumption are in the same order of magnitude as cities' overall territorial emissions and that local policy leverage to reduce upstream emissions is larger than typically assumed.

Effect of VOC emissions from vegetation on urban air quality during hot periods

NASA Astrophysics Data System (ADS)

Churkina, Galina; Kuik, Friderike; Bonn, Boris; Lauer, Axel; Grote, Ruediger; Butler, Tim

2016-04-01

Programs to plant millions of trees in cities around the world aim at the reduction of summer temperatures, increase of carbon storage, storm water control, and recreational space, as well as at poverty alleviation. These urban greening programs, however, do not take into account how closely human and natural systems are coupled in urban areas. Compared with the surroundings of cities, elevated temperatures together with high anthropogenic emissions of air and water pollutants are quite typical in urban systems. Urban and sub-urban vegetation respond to changes in meteorology and air quality and can react to pollutants. Neglecting this coupling may lead to unforeseen negative effects on air quality resulting from urban greening programs. The potential of emissions of volatile organic compounds (VOC) from vegetation combined with anthropogenic emissions of air pollutants to produce ozone has long been recognized. This ozone formation potential increases under rising temperatures. Here we investigate how emissions of VOC from urban vegetation affect corresponding ground-level ozone and PM10 concentrations in summer and especially during heat wave periods. We use the Weather Research and Forecasting Model with coupled atmospheric chemistry (WRF-CHEM) to quantify these feedbacks in the Berlin-Brandenburg region, Germany during the two summers of 2006 (heat wave) and 2014 (reference period). VOC emissions from vegetation are calculated by MEGAN 2.0 coupled online with WRF-CHEM. Our preliminary results indicate that the contribution of VOCs from vegetation to ozone formation may increase by more than twofold during heat wave periods. We highlight the importance of the vegetation for urban areas in the context of a changing climate and discuss potential tradeoffs of urban greening programs.

Modelling the catchment-scale environmental impacts of wastewater treatment in an urban sewage system for CO₂ emission assessment.

PubMed

Mouri, Goro; Oki, Taikan

2010-01-01

Water shortages and water pollution are a global problem. Increases in population can have further acute effects on water cycles and on the availability of water resources. Thus, wastewater management plays an important role in mitigating negative impacts on natural ecosystems and human environments and is an important area of research. In this study, we modelled catchment-scale hydrology, including water balances, rainfall, contamination, and urban wastewater treatment. The entire water resource system of a basin, including a forest catchment and an urban city area, was evaluated synthetically from a spatial distribution perspective with respect to water quantity and quality; the Life Cycle Assessment (LCA) technique was applied to optimize wastewater treatment management with the aim of improving water quality and reducing CO₂ emissions. A numerical model was developed to predict the water cycle and contamination in the catchment and city; the effect of a wastewater treatment system on the urban region was evaluated; pollution loads were evaluated quantitatively; and the effects of excluding rainwater from the treatment system during flooding and of urban rainwater control on water quality were examined. Analysis indicated that controlling the amount of rainwater inflow to a wastewater treatment plant (WWTP) in an urban area with a combined sewer system has a large impact on reducing CO₂ emissions because of the load reduction on the urban sewage system.

Low Emissions and Delay Optimization for an Isolated Signalized Intersection Based on Vehicular Trajectories

PubMed Central

2015-01-01

A traditional traffic signal control system is established based on vehicular delay, queue length, saturation and other indicators. However, due to the increasing severity of urban environmental pollution issues and the development of a resource-saving and environmentally friendly social philosophy, the development of low-carbon and energy-efficient urban transport is required. This paper first defines vehicular trajectories and the calculation of vehicular emissions based on VSP. Next, a regression analysis method is used to quantify the relationship between vehicular emissions and delay, and a traffic signal control model is established to reduce emissions and delay using the enumeration method combined with saturation constraints. Finally, one typical intersection of Changchun is selected to verify the model proposed in this paper; its performance efficiency is also compared using simulations in VISSIM. The results of this study show that the proposed model can significantly reduce vehicle delay and traffic emissions simultaneously. PMID:26720095

Low Emissions and Delay Optimization for an Isolated Signalized Intersection Based on Vehicular Trajectories.

PubMed

Lin, Ciyun; Gong, Bowen; Qu, Xin

2015-01-01

A traditional traffic signal control system is established based on vehicular delay, queue length, saturation and other indicators. However, due to the increasing severity of urban environmental pollution issues and the development of a resource-saving and environmentally friendly social philosophy, the development of low-carbon and energy-efficient urban transport is required. This paper first defines vehicular trajectories and the calculation of vehicular emissions based on VSP. Next, a regression analysis method is used to quantify the relationship between vehicular emissions and delay, and a traffic signal control model is established to reduce emissions and delay using the enumeration method combined with saturation constraints. Finally, one typical intersection of Changchun is selected to verify the model proposed in this paper; its performance efficiency is also compared using simulations in VISSIM. The results of this study show that the proposed model can significantly reduce vehicle delay and traffic emissions simultaneously.

Improvement of health risk factors after reduction of VOC concentrations in industrial and urban areas.

PubMed

Lerner, Jorge Esteban Colman; Kohajda, Tibor; Aguilar, Myriam Elisabeth; Massolo, Laura Andrea; Sánchez, Erica Yanina; Porta, Atilio Andrés; Opitz, Philipp; Wichmann, Gunnar; Herbarth, Olf; Mueller, Andrea

2014-01-01

After reductions of fugitive and diffuse emissions by an industrial complex, a follow-up study was performed to determine the time variability of volatile organic compounds (VOCs) and the lifetime cancer risk (LCR). Passive samplers (3 M monitors) were placed outdoors (n = 179) and indoors (n = 75) in industrial, urban, and control areas for 4 weeks. Twenty-five compounds including n-alkanes, cycloalkanes, aromatics, chlorinated hydrocarbons, and terpenes were determined by GC/MS. The results show a significant decrease of all VOCs, especially in the industrial area and to a lesser extent in the urban area. The median outdoor concentration of benzene in the industrial area declined compared to the former study, around 85% and about 50% in the urban area, which in the past was strongly influenced by industrial emissions. Other carcinogenic compounds like styrene and tetrachloroethylene were reduced to approximately 60%. VOC concentrations in control areas remained nearly unchanged. According to the determined BTEX ratios and interspecies correlations, in contrast to the previous study, traffic was identified as the main emission source in the urban and control areas and showed an increased influence in the industrial area. The LCR, calculated for benzene, styrene, and tetrachloroethylene, shows a decrease of one order of magnitude in accordance to the decreased total VOC concentrations and is now acceptable according to values proposed by the World Health Organization.

Atmospheric polycyclic aromatic hydrocarbons in the urban environment: Occurrence, toxicity and source apportionment.

PubMed

Mishra, Nitika; Ayoko, Godwin A; Morawska, Lidia

2016-01-01

Polycyclic Aromatic Hydrocarbons (PAHs) represent a major class of toxic pollutants because of their carcinogenic and mutagenic characteristics. People living in urban areas are regularly exposed to PAHs because of abundance of their emission sources. Within this context, this study aimed to: (i) identify and quantify the levels of ambient PAHs in an urban environment; (ii) evaluate their toxicity; and (iii) identify their sources as well as the contribution of specific sources to measured concentrations. Sixteen PAHs were identified and quantified in air samples collected from Brisbane. Principal Component Analysis - Absolute Principal Component Scores (PCA-APCS) was used in order to conduct source apportionment of the measured PAHs. Vehicular emissions, natural gas combustion, petrol emissions and evaporative/unburned fuel were the sources identified; contributing 56%, 21%, 15% and 8% of the total PAHs emissions, respectively, all of which need to be considered for any pollution control measures implemented in urban areas. Copyright © 2015 Elsevier Ltd. All rights reserved.

40 CFR 86.115-78 - EPA urban dynamometer driving schedule.

Code of Federal Regulations, 2013 CFR

2013-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission.... time relationships. They each consist of a distinct nonrepetitive series of idle, acceleration, cruise...

40 CFR 86.115-78 - EPA urban dynamometer driving schedule.

Code of Federal Regulations, 2011 CFR

2011-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission.... time relationships. They each consist of a distinct nonrepetitive series of idle, acceleration, cruise...

40 CFR 86.115-78 - EPA urban dynamometer driving schedule.

Code of Federal Regulations, 2012 CFR

2012-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission.... time relationships. They each consist of a distinct nonrepetitive series of idle, acceleration, cruise...

Volatile organic compound fluxes and concentrations in London (ClearfLo)

NASA Astrophysics Data System (ADS)

Valach, Amy; Langford, Ben; Nemitz, Eiko; MacKenzie, Rob; Hewitt, Nick

2014-05-01

Volatile organic compounds (VOCs) from anthropogenic sources such as fuel combustion or evaporative emissions can directly and indirectly affect human health. Some VOCs, such as benzene and 1,3- butadiene are carcinogens. These and other VOCs contribute to the formation of ozone (O3) and aerosol particles, which have effects on human health and the radiative balance of the atmosphere. Although in the UK VOC emissions are subject to control under European Commission Directive 2008/50/EC and emission reducing technologies have been implemented, urban air pollution remains a concern. Urban air quality is likely to remain a priority since currently >50% of the global population live in urban areas with trends in urbanization and population migration predicted to increase. The ClearfLo project is a large multi-institutional consortium funded by the UK Natural Environment Research Council (NERC) and provides integrated measurements of meteorology, gas phase and particulate composition of the atmosphere over London. Both long term and IOP measurements were made at street and elevated locations at a range of sites across London and its surroundings during 2011 and 2012. Mixing ratios of a selection of nine VOCs were measured using a high sensitivity proton transfer reaction-mass spectrometer (PTR-MS) at a ground level urban background (North Kensington) and kerbside (Marylebone Road) site during the winter IOP. VOC fluxes were measured by virtually disjunct eddy covariance (vDEC) at an elevated urban site (King's College Strand) in Aug-Dec 2012. Our results for the first IOP showed that most of the selected compound concentrations depended on traffic emissions, although there was a marked difference between the urban background and kerbside sites. We identified some temperature effects on VOC concentrations. We also present the first analyses of VOC flux measurements over London. Preliminary analyses indicate most compounds associated with vehicle emissions closely followed diurnal traffic counts. Fluxes of isoprene and methanol appear to be controlled by light intensity and temperature, consistent with a predominantly biogenic source of these compounds.

40 CFR 86.515-78 - EPA urban dynamometer driving schedule.

Code of Federal Regulations, 2014 CFR

2014-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission... nonrepetitive series of idle, acceleration, cruise, and deceleration modes of various time sequences and rates...

40 CFR 86.515-78 - EPA urban dynamometer driving schedule.

Code of Federal Regulations, 2012 CFR

2012-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission... nonrepetitive series of idle, acceleration, cruise, and deceleration modes of various time sequences and rates...

40 CFR 86.515-78 - EPA urban dynamometer driving schedule.

Code of Federal Regulations, 2011 CFR

2011-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission... nonrepetitive series of idle, acceleration, cruise, and deceleration modes of various time sequences and rates...

40 CFR 86.515-78 - EPA urban dynamometer driving schedule.

Code of Federal Regulations, 2013 CFR

2013-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission... nonrepetitive series of idle, acceleration, cruise, and deceleration modes of various time sequences and rates...

Constraining the uncertainty in emissions over India with a regional air quality model evaluation

NASA Astrophysics Data System (ADS)

Karambelas, Alexandra; Holloway, Tracey; Kiesewetter, Gregor; Heyes, Chris

2018-02-01

To evaluate uncertainty in the spatial distribution of air emissions over India, we compare satellite and surface observations with simulations from the U.S. Environmental Protection Agency (EPA) Community Multi-Scale Air Quality (CMAQ) model. Seasonally representative simulations were completed for January, April, July, and October 2010 at 36 km × 36 km using anthropogenic emissions from the Greenhouse Gas-Air Pollution Interaction and Synergies (GAINS) model following version 5a of the Evaluating the Climate and Air Quality Impacts of Short-Lived Pollutants project (ECLIPSE v5a). We use both tropospheric columns from the Ozone Monitoring Instrument (OMI) and surface observations from the Central Pollution Control Board (CPCB) to closely examine modeled nitrogen dioxide (NO2) biases in urban and rural regions across India. Spatial average evaluation with satellite retrievals indicate a low bias in the modeled tropospheric column (-63.3%), which reflects broad low-biases in majority non-urban regions (-70.1% in rural areas) across the sub-continent to slightly lesser low biases reflected in semi-urban areas (-44.7%), with the threshold between semi-urban and rural defined as 400 people per km2. In contrast, modeled surface NO2 concentrations exhibit a slight high bias of +15.6% when compared to surface CPCB observations predominantly located in urban areas. Conversely, in examining extremely population dense urban regions with more than 5000 people per km2 (dense-urban), we find model overestimates in both the column (+57.8) and at the surface (+131.2%) compared to observations. Based on these results, we find that existing emission fields for India may overestimate urban emissions in densely populated regions and underestimate rural emissions. However, if we rely on model evaluation with predominantly urban surface observations from the CPCB, comparisons reflect model high biases, contradictory to the knowledge gained using satellite observations. Satellites thus serve as an important emissions and model evaluation metric where surface observations are lacking, such as rural India, and support improved emissions inventory development.

Exploring Relationships between North American Urban Form and Rates of Urban CO2 Emissions: A System Dynamics Approach

NASA Astrophysics Data System (ADS)

Emmi, P. C.; Forster, C. B.; Mills, J. I.; Call, B. D.; Sabula, J.; Klewicki, J. C.; Pataki, D. E.; Peterson, T. R.

2004-12-01

Cities are the locus of North America's most intense consumption of fossil fuels. Thus the rate and character of urbanization influence the rate of urban CO2 released into the global atmosphere. The rate of rural-to-urban land conversion, and changes in the population density of urban land, are influenced by coupled changes in urban demographics and the local economy. Urban sprawl (a rapid expansion of urban land with low population densities) is governed by a self-reinforcing feedback effect between urban transportation infrastructure investments (road building) and urban land development where road building begets new urban neighborhoods that, in turn, induce more road building that begets additional new neighborhoods. If unrestrained, this feedback effect leads to the unrestrained expansion of urban sprawl, urban vehicular travel and traffic congestion. This self-reinforcing feedback loop forms a key dynamic that controls the rate at which CO2-emitting fossil fuels are burned for transportation, electricity production, heating, and commercial/industrial processes. In a rapidly sprawling city residents must travel increasingly greater distances between work, shopping, and home while commercial service vehicles must travel to increasingly remote residential locations. The increasing number of vehicle trips and vehicle miles traveled, combined with the growing prevalence of ever-lower density urban land development, leads to a rapid increase in mobile and stationary CO2 emissions. A more compact and punctuated form of urban development with higher-density and mixed-use urban activity centers leads to reduced CO2 emissions. Those who shape urban development policy are often unconcerned by increasing CO2 emissions unless they can be linked to: (1) local concerns about criteria air pollutant emissions and air quality, (2) the dependency of federal infrastructure funding on meeting ambient air quality standards, and (3) the consequences of human exposure to health risks associated with declining air quality. The dynamic simulation of urban systems demonstrates that a suite of policies can be found to diminish sprawl and defeat traffic congestion thereby safeguarding the vitality a city. A systems thinking approach, facilitated by a community engagement process, has further enabled community opinion leaders and policy makers to map the key features, linkages and feedbacks of a complex, CO2-emitting urban ecosystem. A corresponding lumped-parameter, simulation model provides a framework for decision makers and stakeholders to explore the consequences of alternative options for managing urban growth, sprawl and congestion while also reducing CO2 emissions.

On-road vehicle emission control in Beijing: past, present, and future.

PubMed

Wu, Ye; Wang, Renjie; Zhou, Yu; Lin, Bohong; Fu, Lixin; He, Kebin; Hao, Jiming

2011-01-01

Beijing, the capital of China, has experienced rapid motorization since 1990; a trend that is likely to continue. The growth in vehicles and the corresponding emissions create challenges to improving the urban air quality. In an effort to reduce the impact of vehicle emissions on urban air quality, Beijing has adopted a number of vehicle emission control strategies and policies since the mid 1990 s. These are classified into seven categories: (1) emission control on new vehicles; (2) emission control on in-use vehicles; (3) fuel quality improvements; (4) alternative-fuel and advanced vehicles; (5) economic policies; (6) public transport; and (7) temporal traffic control measures. Many have proven to be successful, such as the Euro emission standards, unleaded gasoline and low sulfur fuel, temporal traffic control measures during the Beijing Olympic Games, etc. Some, however, have been failures, such as the gasoline-to-LPG taxi retrofit program. Thanks to the emission standards for new vehicles as well as other controls, the fleet-average emission rates of CO, HC, NO(X), and PM(10) by each major vehicle category are decreasing over time. For example, gasoline cars decreased fleet-average emission factors by 12.5% for CO, 10.0% for HC, 5.8% for NO(X), and 13.0% for PM(10) annually since 1995, and such a trend is likely to continue. Total emissions for Beijing's vehicle fleet increased from 1995 to 1998. However, they show a clear and steady decrease between 1999 and 2009. In 2009, total emissions of CO, HC, NO(X), and PM(10) were 845,000 t, 121,000 t, 84,000 t, and 3700 t, respectively; with reductions of 47%, 49%, 47%, and 42%, relative to 1998. Beijing has been considered a pioneer in controlling vehicle emissions within China, similar to the role of California to the U.S. The continued rapid growth of vehicles, however, is challenging Beijing's policy-makers.

Urban Heat Islands and Their Mitigation vs. Local Impacts of Climate Change

NASA Astrophysics Data System (ADS)

Taha, H.

2007-12-01

Urban heat islands and their mitigation take on added significance, both negative and positive, when viewed from a climate-change perspective. In negative terms, urban heat islands can act as local exacerbating factors, or magnifying lenses, to the effects of regional and large-scale climate perturbations and change. They can locally impact meteorology, energy/electricity generation and use, thermal environment (comfort and heat waves), emissions of air pollutants, photochemistry, and air quality. In positive terms, on the other hand, mitigation of urban heat islands (via urban surface modifications and control of man-made heat, for example) can potentially have a beneficial effect of mitigating the local negative impacts of climate change. In addition, mitigation of urban heat islands can, in itself, contribute to preventing regional and global climate change, even if modestly, by helping reduce CO2 emissions from power plants and other sources as a result of decreased energy use for cooling (both direct and indirect) and reducing the rates of meteorology-dependent emissions of air pollutants. This presentation will highlight aspects and characteristics of heat islands, their mitigation, their modeling and quantification techniques, and recent advances in meso-urban modeling of California (funded by the California Energy Commission). In particular, the presentation will focus on results from quantitative, modeling-based analyses of the potential benefits of heat island mitigation in 1) reducing point- and area-source emissions of CO2, NOx, and VOC as a result of reduced cooling energy demand and ambient/surface temperatures, 2) reducing evaporative and fugitive hydrocarbon emissions as a result of lowered temperatures, 3) reducing biogenic hydrocarbon emissions from existing vegetative cover, 4) slowing the rates of tropospheric/ground-level ozone formation and/or accumulation in the urban boundary layer, and 5) helping improve air quality. Quantitative estimates of the above will be presented based on recent and earlier meteorological, energy, thermal environmental, emissions, and photochemical modeling studies for California and Texas.

The changing face of urban air pollution

NASA Astrophysics Data System (ADS)

Lewis, Alastair C.

2018-02-01

The atmospheric chemistry that leads to photochemical smog and climate-active aerosols requires the presence of volatile organic compounds (VOCs) (1, 2). The VOCs in urban air typically derive from the prevailing energy and transport technologies as well as the use of petrochemical-derived products. On page 760 of this issue, McDonald et al. (3) report that a notable change in emissions may be underway in U.S. cities, with effects on secondary pollutants such as organic aerosols. Shifting from an urban atmosphere dominated by transport-related VOCs to one dominated by VOCs from coatings, adhesives, and consumer products would alter predictions of urban air quality and challenge the existing policy framework for emissions control.

The URban Greenhouse gas Emissions assessment through inverse modeling (URGE) project: a pilot study in the Oslo area

NASA Astrophysics Data System (ADS)

Pisso, I. J.; Lopez-Aparicio, S.; Schneider, P.; Schmidbauer, N.; Vogt, M.

2017-12-01

Norway has set the target of cutting greenhouse gas (GHG) emissions by at least 40% compared to 1990 levels by 2030. This goal will require the implementation of policy measures aiming at strong reductions of GHGs emissions, especially in the urban environment. The implementation of urban policy measures is still a challenging task and it requires control and verification for success. The URGE project aims at assessing the emission flux of GHGs including comprehensive uncertainty estimates based on inverse transport modelling techniques and optimized use of measurements. The final goal is to establish a coherent and consistent GHG urban emission inventory. This will be carried out in a case study in Oslo (Norway), where CO2 will be the priority compound. The overall outcome of the project will provide support in the development of strategies to effectively reduce GHG emissions in the urban environment. The overall goal will be reached through establishing the baseline urban CO2 emission inventory for Oslo; determining the optimal measurement locations based on transport modelling (with flexpart-wrf); designing and carrying out a pilot measurement campaign of the CO2-rich air downwind of the city plume combining state-of-the-art instruments (Picarro) and small sensors; assessing the feasibility of determining the background concentration surrounding the city with satellite measurements (OCO2); and providing optimised estimates of the emissions and their uncertainties via inverse modelling (source-receptor relationship). One of our main interests is the interoperability and exchange of information with similar activities in other urban areas. We will present the overall project and the preliminary results of the network design. We will discuss the data exchange formats, the algorithms and data structures that could be used for results and methodology intercomparisons as well as the suitability to apply the same techniques to other atmospheric compounds.

Does Historical Urban Density Explain the Variation in Per Capita Carbon Dioxide Emissions Across U.S. Cities?

NASA Astrophysics Data System (ADS)

Campbell, K. B.

2013-12-01

The shape a city takes can have long-term impacts. The built environment is durable, and urban infrastructure is costly to alter post-construction, so decisions made early in a city's history have a lasting effect. Cities are some of the biggest aggregate sources of CO2 emissions but are also the areas with the lowest per capita emissions. Even though per capita emissions in urban areas are less than their rural counterparts, the variation in emissions across cities is drastic and understanding this variation can improve the way we build and plan cities. Research has been conducted on how density correlates with per capita emissions, but little has been done on how historical growth has influenced emissions. Using historical census data and the Vulcan Project's fossil fuel CO2 emissions data product, I investigate in greater detail whether historical population density in U.S. cities has had a significant impact on future CO2 emissions in the urban area and in the surrounding region. The census data includes all places that have reported a population of over 100,000 people in any decennial census between 1790 and 2000 and the land area the year that the city first crosses that 100,000-population threshold. This data is used to create the historical density measure. The Vulcan CO2 emissions data is broken down by sector. For this project I use the residential, commercial, and transportation (on road and non-road) emissions sectors on a 10x10km grid in 2002. I also control for regional variation in heating and cooling days, current urban density, average house age, median income, and variation in residential heating (gas, electric, fuel oil, and coal) as these are all known correlates of carbon dioxide emissions. Understanding if historical density better explains the variation in per capita carbon dioxide emissions across cities will help urban planners and city governments decide if it is appropriate to regulate growth during the initial boom of a city, a regulation that can be costly.

Assessing and evaluating urban VOC emissions in mid-latitude megacities from intensive observations in Paris and Los Angeles

NASA Astrophysics Data System (ADS)

Borbon, A.; Gilman, J. B.; Kuster, W. C.; McKeen, S. A.; Holloway, J. S.; Gros, V.; Gaimoz, C.; Beekmann, M.; De Gouw, J. A.

2011-12-01

Volatile Organic Compounds (VOC) affect urban air quality and regional climate change by contributing to ozone formation and the build-up of Secondary Organic Aerosols (SOA). Quantification of VOC emissions is a first critical step to predict VOC environmental impacts and to design effective abatement strategies. Indeed, the quality of ozone and SOA forecasts strongly depends on an accurate knowledge of the primary VOC emissions. However, commonly used bottom-up approaches are highly uncertain due to source multiplicity (combustion processes, storage and distribution of fossil fuels, solvent use, etc.) because of numerous controlling factors (driving conditions, fuel type, temperature, radiation, etc.), and their great variability in time and space. Field observations of VOC and other trace gases can provide valuable top-down constraints to evaluate VOC emission inventories at urban scales. In addition, the implementation of emission reduction measures raises the question of the increasing importance of VOC sources other than traffic. Here, we will evaluate VOC emissions of two mid-latitude megacities in the Northern Hemisphere: the Greater Paris area (Europe) and Los Angeles (USA). In 2009 and 2010, three intensive field campaigns took place in Paris and Los Angeles in the framework of the MEGAPOLI (EU FP7) and CalNex-2010 projects, respectively. Very detailed measurements of aerosol composition and properties, and their gaseous VOC precursors were carried out at ground-based sites (urban center and suburban) and on various mobile platforms. This contribution uses a comprehensive suite of VOC measurements collected by GC-MS/FID techniques at ground-based sites in both cities by a source-receptor methodology. First, emission ratios were estimated from the observations (uncertainty of ± 20%) and compared regarding regional characteristics and European vs. Californian control policies. Then, determined emission ratios were used to assess the accuracy of up-to-date emission inventories. While emission ratios agree within the uncertainties for many VOCs, remarkable differences are observed for aromatic VOCs (C7-C9) depending on the season. Moreover, the evaluation of emission inventories shows large discrepancies for VOCs for which traffic is not the dominant source. Commonalities and/or differences are also discussed in term of implication for urban atmospheric chemistry (ozone and SOA formation potential) in both megacities.

Vegetation and other development options for mitigating urban air pollution impacts

EPA Science Inventory

In addition to installing air pollution control devices and reducing emissions activities, urban air pollution can be further mitigated through planning and design strategies including vegetation planting, building design, installing roadside and near source structures, and modif...

Estimating greenhouse gas emissions of European cities--modeling emissions with only one spatial and one socioeconomic variable.

PubMed

Baur, Albert H; Lauf, Steffen; Förster, Michael; Kleinschmit, Birgit

2015-07-01

Substantive and concerted action is needed to mitigate climate change. However, international negotiations struggle to adopt ambitious legislation and to anticipate more climate-friendly developments. Thus, stronger actions are needed from other players. Cities, being greenhouse gas emission centers, play a key role in promoting the climate change mitigation movement by becoming hubs for smart and low-carbon lifestyles. In this context, a stronger linkage between greenhouse gas emissions and urban development and policy-making seems promising. Therefore, simple approaches are needed to objectively identify crucial emission drivers for deriving appropriate emission reduction strategies. In analyzing 44 European cities, the authors investigate possible socioeconomic and spatial determinants of urban greenhouse gas emissions. Multiple statistical analyses reveal that the average household size and the edge density of discontinuous dense urban fabric explain up to 86% of the total variance of greenhouse gas emissions of EU cities (when controlled for varying electricity carbon intensities). Finally, based on these findings, a multiple regression model is presented to determine greenhouse gas emissions. It is independently evaluated with ten further EU cities. The reliance on only two indicators shows that the model can be easily applied in addressing important greenhouse gas emission sources of European urbanites, when varying power generations are considered. This knowledge can help cities develop adequate climate change mitigation strategies and promote respective policies on the EU or the regional level. The results can further be used to derive first estimates of urban greenhouse gas emissions, if no other analyses are available. Copyright © 2015 Elsevier B.V. All rights reserved.

CO2 emissions, real output, energy consumption, trade, urbanization and financial development: testing the EKC hypothesis for the USA.

PubMed

Dogan, Eyup; Turkekul, Berna

2016-01-01

This study aims to investigate the relationship between carbon dioxide (CO2) emissions, energy consumption, real output (GDP), the square of real output (GDP(2)), trade openness, urbanization, and financial development in the USA for the period 1960-2010. The bounds testing for cointegration indicates that the analyzed variables are cointegrated. In the long run, energy consumption and urbanization increase environmental degradation while financial development has no effect on it, and trade leads to environmental improvements. In addition, this study does not support the validity of the environmental Kuznets curve (EKC) hypothesis for the USA because real output leads to environmental improvements while GDP(2) increases the levels of gas emissions. The results from the Granger causality test show that there is bidirectional causality between CO2 and GDP, CO2 and energy consumption, CO2 and urbanization, GDP and urbanization, and GDP and trade openness while no causality is determined between CO2 and trade openness, and gas emissions and financial development. In addition, we have enough evidence to support one-way causality running from GDP to energy consumption, from financial development to output, and from urbanization to financial development. In light of the long-run estimates and the Granger causality analysis, the US government should take into account the importance of trade openness, urbanization, and financial development in controlling for the levels of GDP and pollution. Moreover, it should be noted that the development of efficient energy policies likely contributes to lower CO2 emissions without harming real output.

The contribution of megacities to regional sulfur pollution in Asia

NASA Astrophysics Data System (ADS)

Guttikunda, Sarath K.; Carmichael, Gregory R.; Calori, Giuseppe; Eck, Christina; Woo, Jung-Hun

Asia is undergoing rapid urbanization resulting in increasing air pollution threats in its cities. The contribution of megacities to sulfur emissions and pollution in Asia is studied over a 25-year period (1975-2000) using a multi-layer Lagrangian puff transport model. Asian megacities cover <2% of the land area but emit ˜16% of the total anthropogenic sulfur emissions of Asia. It is shown that urban sulfur emissions contribute over 30% to the regional pollution levels in large parts of Asia. The average contribution of megacities over the western Pacific increased from <5% in 1975 to >10% in 2000. Two future emission scenarios are evaluated for 2020—"business as usual (BAU)" and "maximum feasible controls (MAXF)" to establish the range of reductions possible for these cities. The MAXF scenario would result in 2020 S-emissions that are ˜80% lower than those in 2000, at an estimated control cost of US 87 billion per year (1995 US) for all of Asia. An urban scale analysis of sulfur pollution for four megacities—Shanghai, and Chongqing in China; Seoul in South Korea; and Mumbai (formerly Bombay) in India is presented. If pollution levels were allowed to increase under BAU, over 30 million people in these cities alone would be exposed to levels in excess of the WHO guidelines.

Premature deaths attributed to source-specific BC emissions in six urban US regions

NASA Astrophysics Data System (ADS)

Turner, Matthew D.; Henze, Daven K.; Capps, Shannon L.; Hakami, Amir; Zhao, Shunliu; Resler, Jaroslav; Carmichael, Gregory R.; Stanier, Charles O.; Baek, Jaemeen; Sandu, Adrian; Russell, Armistead G.; Nenes, Athanasios; Pinder, Rob W.; Napelenok, Sergey L.; Bash, Jesse O.; Percell, Peter B.; Chai, Tianfeng

2015-11-01

Recent studies have shown that exposure to particulate black carbon (BC) has significant adverse health effects and may be more detrimental to human health than exposure to PM2.5 as a whole. Mobile source BC emission controls, mostly on diesel-burning vehicles, have successfully decreased mobile source BC emissions to less than half of what they were 30 years ago. Quantification of the benefits of previous emissions controls conveys the value of these regulatory actions and provides a method by which future control alternatives could be evaluated. In this study we use the adjoint of the Community Multiscale Air Quality (CMAQ) model to estimate highly-resolved spatial distributions of benefits related to emission reductions for six urban regions within the continental US. Emissions from outside each of the six chosen regions account for between 7% and 27% of the premature deaths attributed to exposure to BC within the region. While we estimate that nonroad mobile and onroad diesel emissions account for the largest number of premature deaths attributable to exposure to BC, onroad gasoline is shown to have more than double the benefit per unit emission relative to that of nonroad mobile and onroad diesel. Within the region encompassing New York City and Philadelphia, reductions in emissions from large industrial combustion sources that are not classified as EGUs (i.e., non-EGU) are estimated to have up to triple the benefits per unit emission relative to reductions to onroad diesel sectors, and provide similar benefits per unit emission to that of onroad gasoline emissions in the region. While onroad mobile emissions have been decreasing in the past 30 years and a majority of vehicle emission controls that regulate PM focus on diesel emissions, our analysis shows the most efficient target for stricter controls is actually onroad gasoline emissions.

Optimize pollutant emissions through adaptive highway management.

DOT National Transportation Integrated Search

2011-09-01

In this project, we investigated the possibility to reduce green house emission : (mainly CO2) from urban highways by adaptive ramp meter control. QUADSTONE : PARAMICS software was used to build a microscopic traffic model for a 4-lane highway : sect...

Evolution of air pollution source contributions over one decade, derived by PM10 and PM2.5 source apportionment in two metropolitan urban areas in Greece

NASA Astrophysics Data System (ADS)

Diapouli, E.; Manousakas, M.; Vratolis, S.; Vasilatou, V.; Maggos, Th; Saraga, D.; Grigoratos, Th; Argyropoulos, G.; Voutsa, D.; Samara, C.; Eleftheriadis, K.

2017-09-01

Metropolitan Urban areas in Greece have been known to suffer from poor air quality, due to variety of emission sources, topography and climatic conditions favouring the accumulation of pollution. While a number of control measures have been implemented since the 1990s, resulting in reductions of atmospheric pollution and changes in emission source contributions, the financial crisis which started in 2009 has significantly altered this picture. The present study is the first effort to assess the contribution of emission sources to PM10 and PM2.5 concentration levels and their long-term variability (over 5-10 years), in the two largest metropolitan urban areas in Greece (Athens and Thessaloniki). Intensive measurement campaigns were conducted during 2011-2012 at suburban, urban background and urban traffic sites in these two cities. In addition, available datasets from previous measurements in Athens and Thessaloniki were used in order to assess the long-term variability of concentrations and sources. Chemical composition analysis of the 2011-2012 samples showed that carbonaceous matter was the most abundant component for both PM size fractions. Significant increase of carbonaceous particle concentrations and of OC/EC ratio during the cold period, especially in the residential urban background sites, pointed towards domestic heating and more particularly wood (biomass) burning as a significant source. PMF analysis further supported this finding. Biomass burning was the largest contributing source at the two urban background sites (with mean contributions for the two size fractions in the range of 24-46%). Secondary aerosol formation (sulphate, nitrate & organics) was also a major contributing source for both size fractions at the suburban and urban background sites. At the urban traffic site, vehicular traffic (exhaust and non-exhaust emissions) was the source with the highest contributions, accounting for 44% of PM10 and 37% of PM2.5, respectively. The long-term variability of emission sources in the two cities (over 5-10 years), assessed through a harmonized application of the PMF technique on recent and past year data, clearly demonstrates the effective reduction in emissions during the last decade due to control measures and technological development; however, it also reflects the effects of the financial crisis in Greece during these years, which has led to decreased economic activities and the adoption of more polluting practices by the local population in an effort to reduce living costs.

Temporal characteristics of atmospheric CO2 in urban Nanjing, China

NASA Astrophysics Data System (ADS)

Huang, Xiaoxian; Wang, Tijian; Talbot, Robert; Xie, Min; Mao, Huiting; Li, Shu; Zhuang, Bingliang; Yang, Xiuqun; Fu, Congbin; Zhu, Jialei; Huang, Xing; Xu, Runying

2015-02-01

Although China is a big carbon dioxide (CO2) emitter, in situ measurements of atmospheric CO2 are sparse in urban China. The mixing ratio of carbon dioxide (CO2) and its influencing factors in urban Nanjing were investigated in this study, from the 18th of January to the 31st of December 2011. The annual average mixing ratio of CO2 was 406.5 ± 20.0 ppmv over the study period. The signal analysis using the fast Fourier transform (FFT) algorithm showed that CO2 had different cycles as a result of multiple controlling factors. The seasonal and intra-seasonal fluctuations of CO2 were mainly caused by the terrestrial biospheric uptake and emission and atmospheric oscillation. The weekly variation of CO2 was largely influenced by traffic volume. The diurnal cycle of CO2 presented a bimodal pattern in winter (DJF) probably due to the rush hour emissions. The seasonal mean CO2/CO correlation slope varied from 0.024 ppmv/ppbv to 0.029 ppmv/ppbv, comparable to the fossil fuel combustion emission ratio. The diurnal pattern of CO2/CO was irregular, indicating random anthropogenic emissions in an urban area. Firework setting was a large source of CO2 during the Spring Festival holiday. The backward trajectories by the HYSPLIT model showed that the local anthropogenic emissions contributed the most to the high CO2 mixing ratio in the urban area.

Network design for quantifying urban CO2 emissions: assessing trade-offs between precision and network density

NASA Astrophysics Data System (ADS)

Turner, Alexander J.; Shusterman, Alexis A.; McDonald, Brian C.; Teige, Virginia; Harley, Robert A.; Cohen, Ronald C.

2016-11-01

The majority of anthropogenic CO2 emissions are attributable to urban areas. While the emissions from urban electricity generation often occur in locations remote from consumption, many of the other emissions occur within the city limits. Evaluating the effectiveness of strategies for controlling these emissions depends on our ability to observe urban CO2 emissions and attribute them to specific activities. Cost-effective strategies for doing so have yet to be described. Here we characterize the ability of a prototype measurement network, modeled after the Berkeley Atmospheric CO2 Observation Network (BEACO2N) in California's Bay Area, in combination with an inverse model based on the coupled Weather Research and Forecasting/Stochastic Time-Inverted Lagrangian Transport (WRF-STILT) to improve our understanding of urban emissions. The pseudo-measurement network includes 34 sites at roughly 2 km spacing covering an area of roughly 400 km2. The model uses an hourly 1 × 1 km2 emission inventory and 1 × 1 km2 meteorological calculations. We perform an ensemble of Bayesian atmospheric inversions to sample the combined effects of uncertainties of the pseudo-measurements and the model. We vary the estimates of the combined uncertainty of the pseudo-observations and model over a range of 20 to 0.005 ppm and vary the number of sites from 1 to 34. We use these inversions to develop statistical models that estimate the efficacy of the combined model-observing system in reducing uncertainty in CO2 emissions. We examine uncertainty in estimated CO2 fluxes on the urban scale, as well as for sources embedded within the city such as a line source (e.g., a highway) or a point source (e.g., emissions from the stacks of small industrial facilities). Using our inversion framework, we find that a dense network with moderate precision is the preferred setup for estimating area, line, and point sources from a combined uncertainty and cost perspective. The dense network considered here (modeled after the BEACO2N network with an assumed mismatch error of 1 ppm at an hourly temporal resolution) could estimate weekly CO2 emissions from an urban region with less than 5 % error, given our characterization of the combined observation and model uncertainty.

Network design for quantifying urban CO 2 emissions: assessing trade-offs between precision and network density

DOE PAGES

Turner, Alexander J.; Shusterman, Alexis A.; McDonald, Brian C.; ...

2016-11-01

The majority of anthropogenic CO 2 emissions are attributable to urban areas. While the emissions from urban electricity generation often occur in locations remote from consumption, many of the other emissions occur within the city limits. Evaluating the effectiveness of strategies for controlling these emissions depends on our ability to observe urban CO 2 emissions and attribute them to specific activities. Cost-effective strategies for doing so have yet to be described. Here we characterize the ability of a prototype measurement network, modeled after the Berkeley Atmospheric CO 2 Observation Network (BEACO 2N) in California's Bay Area, in combination with anmore » inverse model based on the coupled Weather Research and Forecasting/Stochastic Time-Inverted Lagrangian Transport (WRF-STILT) to improve our understanding of urban emissions. The pseudo-measurement network includes 34 sites at roughly 2 km spacing covering an area of roughly 400 km 2. The model uses an hourly 1 × 1 km 2 emission inventory and 1 × 1 km 2 meteorological calculations. We perform an ensemble of Bayesian atmospheric inversions to sample the combined effects of uncertainties of the pseudo-measurements and the model. We vary the estimates of the combined uncertainty of the pseudo-observations and model over a range of 20 to 0.005 ppm and vary the number of sites from 1 to 34. We use these inversions to develop statistical models that estimate the efficacy of the combined model–observing system in reducing uncertainty in CO 2 emissions. We examine uncertainty in estimated CO 2 fluxes on the urban scale, as well as for sources embedded within the city such as a line source (e.g., a highway) or a point source (e.g., emissions from the stacks of small industrial facilities). Using our inversion framework, we find that a dense network with moderate precision is the preferred setup for estimating area, line, and point sources from a combined uncertainty and cost perspective. The dense network considered here (modeled after the BEACO 2N network with an assumed mismatch error of 1 ppm at an hourly temporal resolution) could estimate weekly CO 2 emissions from an urban region with less than 5 % error, given our characterization of the combined observation and model uncertainty.« less

Network design for quantifying urban CO 2 emissions: assessing trade-offs between precision and network density

DOE Office of Scientific and Technical Information (OSTI.GOV)

Turner, Alexander J.; Shusterman, Alexis A.; McDonald, Brian C.

The majority of anthropogenic CO 2 emissions are attributable to urban areas. While the emissions from urban electricity generation often occur in locations remote from consumption, many of the other emissions occur within the city limits. Evaluating the effectiveness of strategies for controlling these emissions depends on our ability to observe urban CO 2 emissions and attribute them to specific activities. Cost-effective strategies for doing so have yet to be described. Here we characterize the ability of a prototype measurement network, modeled after the Berkeley Atmospheric CO 2 Observation Network (BEACO 2N) in California's Bay Area, in combination with anmore » inverse model based on the coupled Weather Research and Forecasting/Stochastic Time-Inverted Lagrangian Transport (WRF-STILT) to improve our understanding of urban emissions. The pseudo-measurement network includes 34 sites at roughly 2 km spacing covering an area of roughly 400 km 2. The model uses an hourly 1 × 1 km 2 emission inventory and 1 × 1 km 2 meteorological calculations. We perform an ensemble of Bayesian atmospheric inversions to sample the combined effects of uncertainties of the pseudo-measurements and the model. We vary the estimates of the combined uncertainty of the pseudo-observations and model over a range of 20 to 0.005 ppm and vary the number of sites from 1 to 34. We use these inversions to develop statistical models that estimate the efficacy of the combined model–observing system in reducing uncertainty in CO 2 emissions. We examine uncertainty in estimated CO 2 fluxes on the urban scale, as well as for sources embedded within the city such as a line source (e.g., a highway) or a point source (e.g., emissions from the stacks of small industrial facilities). Using our inversion framework, we find that a dense network with moderate precision is the preferred setup for estimating area, line, and point sources from a combined uncertainty and cost perspective. The dense network considered here (modeled after the BEACO 2N network with an assumed mismatch error of 1 ppm at an hourly temporal resolution) could estimate weekly CO 2 emissions from an urban region with less than 5 % error, given our characterization of the combined observation and model uncertainty.« less

Emissions of nitrogen oxides from US urban areas: estimation from Ozone Monitoring Instrument retrievals for 2005-2014

DOE PAGES

Lu, Z.; Streets, D. G.; de Foy, B.; ...

2015-05-28

Satellite remote sensing of tropospheric nitrogen dioxide (NO 2) can provide valuable information for estimating surface nitrogen oxides (NO x) emissions. Using an exponentially-modified Gaussian (EMG) method and taking into account the effect of wind on observed NO 2 distributions, we estimate three-year moving-average emissions of summertime NO x from 35 US urban areas directly from NO 2 retrievals of the Ozone Monitoring Instrument (OMI) during 2005–2014. Following the conclusions of previous studies that the EMG method provides robust and accurate emission estimates under strong-wind conditions, we derive top-down NO x emissions from each urban area by applying the EMGmore » method to OMI data with wind speeds greater than 3–5 m s -1. Meanwhile, we find that OMI NO 2 observations under weak-wind conditions (i.e., < 3 m s -1) are qualitatively better correlated with the surface NO x source strength in comparison to all-wind OMI maps; and therefore we use them to calculate the satellite-observed NO 2 burdens of urban areas and compare with NO x emission estimates. The EMG results show that OMI-derived NO x emissions are highly correlated ( R > 0.93) with weak-wind OMI NO 2 burdens as well as bottom-up NO x emission estimates over 35 urban areas, implying a linear response of the OMI observations to surface emissions under weak-wind conditions. The simultaneous, EMG-obtained, effective NO 2 lifetimes (~3.5 ± 1.3 h), however, are biased low in comparison to the summertime NO 2 chemical lifetimes. In general, isolated urban areas with NO x emission intensities greater than ~ 2 Mg h -1 produce statistically significant weak-wind signals in three-year average OMI data. From 2005 to 2014, we estimate that total OMI-derived NO x emissions over all selected US urban areas decreased by 49%, consistent with reductions of 43, 47, 49, and 44% in the total bottom-up NO x emissions, the sum of weak-wind OMI NO 2 columns, the total weak-wind OMI NO 2 burdens, and the averaged NO 2 concentrations, respectively, reflecting the success of NO x control programs for both mobile sources and power plants. The decrease rates of these NO x-related quantities are found to be faster (i.e., -6.8 to -9.3% yr -1) before 2010 and slower (i.e., -3.4 to -4.9% yr -1) after 2010. For individual urban areas, we calculate the R values of pair-wise trends among the OMI-derived and bottom-up NO x emissions, the weak-wind OMI NO 2 burdens, and ground-based NO 2 measurements; and high correlations are found for all urban areas (median R = 0.8), particularly large ones ( R up to 0.97). The results of the current work indicate that using the EMG method and considering the wind effect, the OMI data allow for the estimation of NO x emissions from urban areas and the direct constraint of emission trends with reasonable accuracy.« less

Emissions of nitrogen oxides from US urban areas: estimation from Ozone Monitoring Instrument retrievals for 2005–2014

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Z.; Streets, D. G.; de Foy, B.

Satellite remote sensing of tropospheric nitrogen dioxide (NO 2) can provide valuable information for estimating surface nitrogen oxides (NO x) emissions. Using an exponentially modified Gaussian (EMG) method and taking into account the effect of wind on observed NO 2 distributions, we estimate 3-year moving-average emissions of summertime NO x from 35 US (United States) urban areas directly from NO 2 retrievals of the Ozone Monitoring Instrument (OMI) during 2005–2014. Following conclusions of previous studies that the EMG method provides robust and accurate emission estimates under strong-wind conditions, we derive top-down NO x emissions from each urban area by applyingmore » the EMG method to OMI data with wind speeds greater than 3–5 m s -1. Meanwhile, we find that OMI NO 2 observations under weak-wind conditions (i.e., < 3 m s −1) are qualitatively better correlated to the surface NO x source strength in comparison to all-wind OMI maps; therefore, we use them to calculate the satellite-observed NO 2 burdens of urban areas and compare with NO x emission estimates. The EMG results show that OMI-derived NO x emissions are highly correlated ( R > 0.93) with weak-wind OMI NO 2 burdens as well as with bottom-up NO x emission estimates over 35 urban areas, implying a linear response of the OMI observations to surface emissions under weak-wind conditions. The simultaneous EMG-obtained effective NO 2 lifetimes (~ 3.5 ± 1.3 h), however, are biased low in comparison to the summertime NO 2 chemical lifetimes. In general, isolated urban areas with NO x emission intensities greater than ~ 2 Mg h -1 produce statistically significant weak-wind signals in 3-year average OMI data. From 2005 to 2014, we estimate that total OMI-derived NO x emissions over all selected US urban areas decreased by 49 %, consistent with reductions of 43, 47, 49, and 44 % in the total bottom-up NO x emissions, the sum of weak-wind OMI NO 2 columns, the total weak-wind OMI NO 2 burdens, and the averaged NO 2 concentrations, respectively, reflecting the success of NO x control programs for both mobile sources and power plants. The decrease rates of these NO x-related quantities are found to be faster (i.e., -6.8 to -9.3 % yr −1) before 2010 and slower (i.e., -3.4 to -4.9 % yr −1) after 2010. For individual urban areas, we calculate the R values of pair-wise trends among the OMI-derived and bottom-up NO x emissions, the weak-wind OMI NO 2 burdens, and ground-based NO 2 measurements, and high correlations are found for all urban areas (median R= 0.8), particularly large ones ( R up to 0.97). The results of the current work indicate that using the EMG method and considering the wind effect, the OMI data allow for the estimation of NO x emissions from urban areas and the direct constraint of emission trends with reasonable accuracy.« less

Emissions of nitrogen oxides from US urban areas: estimation from Ozone Monitoring Instrument retrievals for 2005-2014

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu, Z.; Streets, D. G.; de Foy, B.

Satellite remote sensing of tropospheric nitrogen dioxide (NO 2) can provide valuable information for estimating surface nitrogen oxides (NO x) emissions. Using an exponentially-modified Gaussian (EMG) method and taking into account the effect of wind on observed NO 2 distributions, we estimate three-year moving-average emissions of summertime NO x from 35 US urban areas directly from NO 2 retrievals of the Ozone Monitoring Instrument (OMI) during 2005–2014. Following the conclusions of previous studies that the EMG method provides robust and accurate emission estimates under strong-wind conditions, we derive top-down NO x emissions from each urban area by applying the EMGmore » method to OMI data with wind speeds greater than 3–5 m s -1. Meanwhile, we find that OMI NO 2 observations under weak-wind conditions (i.e., < 3 m s -1) are qualitatively better correlated with the surface NO x source strength in comparison to all-wind OMI maps; and therefore we use them to calculate the satellite-observed NO 2 burdens of urban areas and compare with NO x emission estimates. The EMG results show that OMI-derived NO x emissions are highly correlated ( R > 0.93) with weak-wind OMI NO 2 burdens as well as bottom-up NO x emission estimates over 35 urban areas, implying a linear response of the OMI observations to surface emissions under weak-wind conditions. The simultaneous, EMG-obtained, effective NO 2 lifetimes (~3.5 ± 1.3 h), however, are biased low in comparison to the summertime NO 2 chemical lifetimes. In general, isolated urban areas with NO x emission intensities greater than ~ 2 Mg h -1 produce statistically significant weak-wind signals in three-year average OMI data. From 2005 to 2014, we estimate that total OMI-derived NO x emissions over all selected US urban areas decreased by 49%, consistent with reductions of 43, 47, 49, and 44% in the total bottom-up NO x emissions, the sum of weak-wind OMI NO 2 columns, the total weak-wind OMI NO 2 burdens, and the averaged NO 2 concentrations, respectively, reflecting the success of NO x control programs for both mobile sources and power plants. The decrease rates of these NO x-related quantities are found to be faster (i.e., -6.8 to -9.3% yr -1) before 2010 and slower (i.e., -3.4 to -4.9% yr -1) after 2010. For individual urban areas, we calculate the R values of pair-wise trends among the OMI-derived and bottom-up NO x emissions, the weak-wind OMI NO 2 burdens, and ground-based NO 2 measurements; and high correlations are found for all urban areas (median R = 0.8), particularly large ones ( R up to 0.97). The results of the current work indicate that using the EMG method and considering the wind effect, the OMI data allow for the estimation of NO x emissions from urban areas and the direct constraint of emission trends with reasonable accuracy.« less

Regional/Urban Air Quality Modeling Assessment over China Using the Models-3/CMAQ System

NASA Astrophysics Data System (ADS)

Fu, J. S.; Jang, C. C.; Streets, D. G.; Li, Z.; Wang, L.; Zhang, Q.; Woo, J.; Wang, B.

2004-12-01

China is the world's most populous country with a fast growing economy that surges in energy comsumption. It has become the second largest energy consumer after the United States although the per capita level is much lower than those found in developed or developing countries. Air pollution has become one of the most important problems of megacities such as Beijing and Shanghai and has serious impacts on public health, causes urban and regional haze. The Models-3/CMAQ modeling application that has been conducted to simulate multi-pollutants in China is presented. The modeling domains cover East Asia (36-kmx36-km) including Japan, South Korea, Korea DPR, Indonesia, Thailand, India and Mongolia, East China (12-kmx12-km) and Beijing/Tianjing, Shanghai (4-kmx4-km). For this study, the Asian emission inventory based on the emission estimates of the year 2000 that supported the NASA TRACE-P program is used. However, the TRACE-P emission inventory was developed for a different purpose such as global modeling. TRACE-P emission inventory may not be practical in urban area. There is no China national emission inventory available. Therefore, TRACE-P emission inventory is used on the East Asia and East China domains. The 8 districts of Beijing and Shanghai local emissions inventory are used to replace TRACE-P in 4-km domains. The meteorological data for the Models-3/CMAQ run are extracted from MM5. The model simulation is performed during the period January 1-20 and July 1-20, 2001 that presented the winter and summer time for China areas. The preliminary model results are shown O3 concentrations are in the range of 80 -120 ppb in the urban area. Lower urban O3 concentrations are shown in Beijing areas, possibly due to underestimation of urban man-made VOC emissions in the TRACE-P inventory and local inventory. High PM2.5 (70ug/m3 in summer and 150ug/m3 in winter) were simulated over metropolitan & downwind areas with significant secondary constituents. More comprehensive simulations in the Beijing, Shanghai areas are presented with sensitivity analysis. A comparison against available ozone and PM measurement data in Beijing, Shanghai is presented. The local emission inventory improvement in China is to be suggested to investigate. The modeling configuration of the Beijing 4-km x 4-km domain is to demonstrate the development of cost-effective control strategies for the air pollution control such as 2008 Olympic Game air quality management plan.

Effect of watershed urbanization on N2O emissions from the Chongqing metropolitan river network, China

NASA Astrophysics Data System (ADS)

He, Yixin; Wang, Xiaofeng; Chen, Huai; Yuan, Xingzhong; Wu, Ning; Zhang, Yuewei; Yue, Junsheng; Zhang, Qiaoyong; Diao, Yuanbin; Zhou, Lilei

2017-12-01

Watershed urbanization, an integrated anthropogenic perturbation, is another considerable global concern in addition to that of global warming and may significantly enrich the N loadings of watersheds, which then greatly influences the nitrous oxide (N2O) production and fluxes of these aquatic systems. However, little is known about the N2O dynamics in human-dominated metropolitan river networks. In this study, we present the temporal and spatial variations in N2O saturation and emission in the Chongqing metropolitan river network, which is undergoing intensified urbanization. The N2O saturation and fluxes at 84 sampling sites ranged from 126% to 10536% and from 4.5 to 1566.8 μmol N2O m-2 d-1, with means of 1780% and 261 μmol N2O m-2 d-1. The riverine N2O saturation and fluxes increased along with the urbanization gradient and urbanization rate, with disproportionately higher values in urban rivers due to the N2O-rich sewage inputs and enriched in situ N substrates. We found a clear seasonal pattern of N2O saturation, which was co-regulated by both water temperature and precipitation. Regression analysis indicated that the N substrates and dissolved oxygen (DO) that controlled nitrogen metabolism acted as good predictors of the N2O emissions of urban river networks. Particularly, phosphorus (P) and hydromorphological factors (water velocity, river size and bottom substrate) had stronger relationships with the N2O saturation and could also be used to predict the N2O emission hotspots in regions with rapid urbanization. In addition, the default emission factors (EF5-r) used in the Intergovernmental Panel on Climate Change (IPCC) methodology may need revision given the differences among the physical and chemical factors in different rivers, especially urban rivers.

Influence of Ship Emissions on Urban Air Quality: A Comprehensive Study Using Highly Time-Resolved Online Measurements and Numerical Simulation in Shanghai.

PubMed

Liu, Zhanmin; Lu, Xiaohui; Feng, Junlan; Fan, Qianzhu; Zhang, Yan; Yang, Xin

2017-01-03

Shanghai has become an international shipping center in the world. In this study, the multiyear measurements and the high resolution air quality model with hourly ship emission inventory were combined to determine the influence of ship emissions on urban Shanghai. The aerosol time-of-flight mass spectrometer (ATOFMS) measurements were carried out at an urban site from April 2009 to January 2013. During the entire sampling time, most of the half-hourly averaged number fractions of primary ship emitted particles varied between 1.0-10.0%. However, the number fraction could reach up to 50% during the ship plume cases. Ship-plume-influenced periods usually occurred in spring and summer. The simulation of Weather Research and Forecasting/Community Multiscale Air Quality model (WRF/CMAQ) with hourly ship emission inventory provided the highly time-resolved concentrations of ship-related air pollutants during a ship plume case. It showed ships could contribute 20-30% (2-7 μg/m 3 ) of the total PM 2.5 within tens of kilometers of coastal and riverside Shanghai during ship-plume-influenced periods. Our results showed that ship emissions have substantial contribution to the air pollution in urban Shanghai. The control measures of ship emission should be taken considering its negative environment and human health effects.

The measurement of carbon dioxide levels in a city canyon

NASA Astrophysics Data System (ADS)

Boyd, Jenny; Budinov, Daniel; Robinson, Iain; Jack, James

2016-10-01

Cities today have two major environmental concerns - carbon emissions and air quality. Global carbon levels are increasing and cities require to show plans to tackle and reduce the amount of carbon which they are emitting. At present carbon emissions in urban areas are calculated rather than measured. In some cities where industrial activity is not carbon intensive, the major contributors are the burning of fuel for heating and the emissions from vehicles. Air quality levels have a direct impact on human health and cities are under increased pressure to demonstrate plans to control and reduce levels of air pollution. Of great importance is the way in which emissions, both carbon rich emissions and pollutants, disperse in a city environment. Little work has been reported on the movement of CO2 in the urban environment and the effect the structure of the environment exerts on the movement and dispersion. This paper describes an investigation into the dispersion of CO2 within an urban environment in the Old Town of the City of Edinburgh, using a hand carried low cost portable CO2 sensor.

Life cycle implications of urban green infrastructure.

PubMed

Spatari, Sabrina; Yu, Ziwen; Montalto, Franco A

2011-01-01

Low Impact Development (LID) is part of a new paradigm in urban water management that aims to decentralize water storage and movement functions within urban watersheds. LID strategies can restore ecosystem functions and reduce runoff loadings to municipal water pollution control facilities (WPCF). This research examines the avoided energy and greenhouse gas (GHG) emissions of select LID strategies using life cycle assessment (LCA) and a stochastic urban watershed model. We estimate annual energy savings and avoided GHG emissions of 7.3 GJ and 0.4 metric tons, respectively, for a LID strategy implemented in a neighborhood in New York City. Annual savings are small compared to the energy and GHG intensity of the LID materials, resulting in slow environmental payback times. This preliminary analysis suggests that if implemented throughout an urban watershed, LID strategies may have important energy cost savings to WPCF, and can make progress towards reducing their carbon footprint. Copyright © 2011 Elsevier Ltd. All rights reserved.

Vegetation and other development options for mitigating urban air pollution impacts

Treesearch

Richard Baldauf; David J. Nowak

2014-01-01

While air pollution control devices and programs are the primary method of reducing emissions, urban air pollution can be further mitigated through planning and design strategies, including vegetation preservation and planting, building design and development, installing roadside and near-source structures, and modifying surrounding terrain features.

Advanced control design for hybrid turboelectric vehicle

NASA Technical Reports Server (NTRS)

Abban, Joseph; Norvell, Johnesta; Momoh, James A.

1995-01-01

The new environment standards are a challenge and opportunity for industry and government who manufacture and operate urban mass transient vehicles. A research investigation to provide control scheme for efficient power management of the vehicle is in progress. Different design requirements using functional analysis and trade studies of alternate power sources and controls have been performed. The design issues include portability, weight and emission/fuel efficiency of induction motor, permanent magnet and battery. A strategic design scheme to manage power requirements using advanced control systems is presented. It exploits fuzzy logic, technology and rule based decision support scheme. The benefits of our study will enhance the economic and technical feasibility of technological needs to provide low emission/fuel efficient urban mass transit bus. The design team includes undergraduate researchers in our department. Sample results using NASA HTEV simulation tool are presented.

Using the Hestia bottom-up FFCO2 emissions estimation to identify drivers and hotspots in urban areas

NASA Astrophysics Data System (ADS)

Rao, P.; Patarasuk, R.; Gurney, K. R.; o'Keefe, D.; Song, Y.; Huang, J.; Buchert, M.; Lin, J. C.; Mendoza, D. L.; Ehleringer, J. R.; Eldering, A.; Miller, C. E.; Duren, R. M.

2015-12-01

Urban areas occupy 3% of the earth's land surface and generate 75% of the fossil fuel carbon dioxide (FFCO2) emissions. We report on the application of the Hestia Project to the Salt Lake County (SLC) and Los Angeles (LA) domains. Hestia quantifies FFCO2 in fine space-time detail across urban domains using a scientific "bottom-up" approach. We explore the utility of the Hestia to inform both urbanization science and greenhouse gas (GHG) mitigation policy. We focus on the residential sector in SLC and the onroad sector in LA as these sectors are large emissions contributors in each locale, and local governments have some authority and policy levers to mitigate these emissions. Multiple regression using sociodemographic data across SLC census block-groups shows that per capita income exhibits a positive relationship with FFCO2 emissions while household size exhibits a negative relationship, after controlling for total population. Housing units per area (i.e., compact development) has little effect on FFCO2 emissions. Rising income in the high-income group has twice as much impact on the emissions as the low-income group. Household size for the low-income group has four times the impact on the emissions as the high-income group. In LA, onroad FFCO2 emissions account for 49% of total emissions, of which 41% is from arterials (intermediate road class). Arterials also have the largest carbon emissions intensity - FFCO2/vehicle distance travelled (VKT) - possibly from high traffic congestion and fleet composition. Non-interstate hotspot emissions (> 419 tC ln-km-1) are equally dominated by particular arterials and collectors (lowest road class) though collectors have a higher VKT. These hotspots occur largely in LA (67%) and Orange (18%) counties and provide targeted information for onroad emissions reduction. Using Hestia to identify FFCO2 emissions drivers and hotpots can aid state and local policy makers in planning the most effective GHG reductions.

Nature of air pollution, emission sources, and management in the Indian cities

NASA Astrophysics Data System (ADS)

Guttikunda, Sarath K.; Goel, Rahul; Pant, Pallavi

2014-10-01

The global burden of disease study estimated 695,000 premature deaths in 2010 due to continued exposure to outdoor particulate matter and ozone pollution for India. By 2030, the expected growth in many of the sectors (industries, residential, transportation, power generation, and construction) will result in an increase in pollution related health impacts for most cities. The available information on urban air pollution, their sources, and the potential of various interventions to control pollution, should help us propose a cleaner path to 2030. In this paper, we present an overview of the emission sources and control options for better air quality in Indian cities, with a particular focus on interventions like urban public transportation facilities; travel demand management; emission regulations for power plants; clean technology for brick kilns; management of road dust; and waste management to control open waste burning. Also included is a broader discussion on key institutional measures, like public awareness and scientific studies, necessary for building an effective air quality management plan in Indian cities.

Does environmental policy affect scaling laws between population and pollution? Evidence from American metropolitan areas

PubMed Central

2017-01-01

Modern cities are engines of production, innovation, and growth. However, urbanization also increases both local and global pollution from household consumption and firms’ production. Do emissions change proportionately to city size or does pollution tend to outpace or lag urbanization? Do emissions scale differently with population versus economic growth or are emissions, population, and economic growth inextricably linked? How are the scaling relationships between emissions, population, and economic growth affected by environmental regulation? This paper examines the link between urbanization, economic growth and pollution using data from Metropolitan Statistical Areas (MSAs) in the United States between 1999 and 2011. We find that the emissions of local air pollution in these MSAs scale according to a ¾ power law with both population size and gross domestic product (GDP). However, the monetary damages from these local emissions scale linearly with both population and GDP. Counties that have previously been out of attainment with the local air quality standards set by the Clean Air Act show an entirely different relationship: local emissions scale according to the square root of population, while the monetary damages from local air pollution follow a 2/3rds power law with population. Counties out of attainment are subject to more stringent emission controls; we argue based on this that enforcement of the Clean Air Act induces sublinear scaling between emissions, damages, and city size. In contrast, we find that metropolitan GDP scales super-linearly with population in all MSAs regardless of attainment status. Summarizing, our findings suggest that environmental policy limits the adverse effects of urbanization without interfering with the productivity benefits that manifest in cities. PMID:28792949

Does environmental policy affect scaling laws between population and pollution? Evidence from American metropolitan areas.

PubMed

Muller, Nicholas Z; Jha, Akshaya

2017-01-01

Modern cities are engines of production, innovation, and growth. However, urbanization also increases both local and global pollution from household consumption and firms' production. Do emissions change proportionately to city size or does pollution tend to outpace or lag urbanization? Do emissions scale differently with population versus economic growth or are emissions, population, and economic growth inextricably linked? How are the scaling relationships between emissions, population, and economic growth affected by environmental regulation? This paper examines the link between urbanization, economic growth and pollution using data from Metropolitan Statistical Areas (MSAs) in the United States between 1999 and 2011. We find that the emissions of local air pollution in these MSAs scale according to a ¾ power law with both population size and gross domestic product (GDP). However, the monetary damages from these local emissions scale linearly with both population and GDP. Counties that have previously been out of attainment with the local air quality standards set by the Clean Air Act show an entirely different relationship: local emissions scale according to the square root of population, while the monetary damages from local air pollution follow a 2/3rds power law with population. Counties out of attainment are subject to more stringent emission controls; we argue based on this that enforcement of the Clean Air Act induces sublinear scaling between emissions, damages, and city size. In contrast, we find that metropolitan GDP scales super-linearly with population in all MSAs regardless of attainment status. Summarizing, our findings suggest that environmental policy limits the adverse effects of urbanization without interfering with the productivity benefits that manifest in cities.

Ozone Climate Penalty and Mortality in a Changing World

NASA Astrophysics Data System (ADS)

Hakami, A.; Zhao, S.; Pappin, A.; Mesbah, M.

2013-12-01

The expected increase in ozone concentrations with temperature is referred to as the climate penalty factor (CPF). Observed ozone trends have resulted in estimations of regional CPFs in the range of 1-3 ppb/K in the Eastern US, and larger values around the globe. We use the adjoint of a regional model (CMAQ) for attributing changes in ozone mortality and attainment metrics to increased temperature levels at each location in North America during the summer of 2007. Unlike previous forward sensitivity analysis studies, we estimate how changes in temperatures at various locations influence such policy-relevant metrics. Our analysis accounts for separate temperature impact pathways through gas-phase chemistry, moisture abundance, and biogenic emissions. We find that water vapor impact, while mostly negative, is positive and large for temperature changes in urban areas. We also find that increased biogenic emissions plays an important role in the overall temperature influence. Our simulations show a wide range of spatial variability in CPFs between -0.4 and 6.2 ppb/K with largest values in urban areas. We also estimate mortality-based CPFs of up to 4 deaths/K for each grid cell, again with large localization in urban areas. This amounts to an estimated 370 deaths/K for the 3-month period of the simulation. We find that this number is almost equivalent to 5% reduction in anthropogenic NOx emissions for each degree increase in temperature. We show how the CPF will change as the result progressive NOx emission controls from various anthropogenic sectors and sources at different locations. Our findings suggest that urban NOx control can be regarded as an adaptation strategy with regards to ozone air quality. Also, the strong temperature dependence in urban environments suggests that the health and attainment burden of urban heat island may be more substantial than previously thought. Spatial distribution of average adjoint-based CPFs Adjoint-based CPF and Mortality CPF (domainwide)

Revealing the unequal household health footprints in China

NASA Astrophysics Data System (ADS)

Zhao, H.; Li, X.; Zhang, Q.

2017-12-01

Household consumption scale and patterns varies among rural and urban, rich and poor households across regions and nations, these bring uneven direct and indirect production related pollutant emissions and related health footprint. Here, by integrating four stat-of-the-art social-economical and physical models, we quantify PM2.5 related health burden from consumption of 12 income groups for rural and urban households in seven regions of China. We show that, despite earn and spend far less than urban residents, rural households show similar health footprints (3.4×10-4 deaths per capita) with that of urban (3.2×10-4 deaths per capita), primarily because 50% of its consumption related deaths were contributed by the less controlled direct biofuel consumption emissions. Income or expenditure is a main contributor of household health footprints, national averagely, the highest income brackets in rural and urban is 1.8 and 3.4 times of their lowest income groups, respectively. From regions perspective, the household in east coast regions show higher footprint than that of central and western regions, and part of their footprint were occurred in central and west regions through trade or atmospheric transportation. Our results indicate that urbanization will not solve the pollution effects, and efforts to reduce the household health impact should focus on the mitigation of the biofuel consumption emissions in rural area and encourage sustainable consumption in urban area.

Continental-scale assessment of long-term trends in wet deposition trajectories: Role of anthropogenic and hydro-climatic drivers

NASA Astrophysics Data System (ADS)

Park, J.; Gall, H. E.; Niyogi, D.; Rao, S.

2012-12-01

The global trend of increased urbanization, and associated increased intensity of energy and material consumption and waste emissions, has contributed to shifts in the trajectories of aquatic, terrestrial, and atmospheric environments. Here, we focus on continental-scale spatiotemporal patterns in two atmospheric constituents (nitrate and sulfate), whose global biogeochemical cycles have been dramatically altered by emissions from mobile and fixed sources in urbanized and industrialized regions. The observed patterns in wet deposition fluxes of nitrate and sulfate are controlled by (1) natural hydro-climatic forcing, and (2) anthropogenic forcing (emissions and regulatory control), both of which are characterized by stochasticity and non-stationarity. We examine long-term wet deposition records in the U.S., Europe, and East Asia to evaluate how anthropogenic and natural forcing factors jointly contributed to the shifting temporal patterns of wet deposition fluxes at continental scales. These data offer clear evidence for successful implementation of regulatory controls and widespread adoption of technologies contributed to improving water quality and mitigation of adverse ecological impacts. We developed a stochastic model to project the future trajectories of wet deposition fluxes in emerging countries with fast growing urban areas. The model generates ellipses within which projected wet deposition flux trajectories are inscribed, similar to the trends in observational data. The shape of the ellipses provides information regarding the relative dominance of anthropogenic (e.g., industrial and urban emissions) versus hydro-climatic drivers (e.g., rainfall patterns, aridity index). Our analysis facilitates projections of the trajectory shift as a result of urbanization and other land-use changes, climate change, and regulatory enforcement. We use these observed data and the model to project likely trajectories for rapidly developing countries (BRIC), with a particular emphasis on various approaches to sustainable economic development. Brazil represents the case of shifts to alternate energy sources (bioethanol and hydroelectric power), while India and China are on the fossil fuel dependent trajectories, the same that North America and Europe had followed. Rapid increases in population, urbanization, and economic development of African cities presents an interesting case study for choices available for sustainable development, similar to that of Brazil rather than that followed by India and China. Coordinated air quality monitoring at urban and reference sites needs to be established to follow the fast-changing conditions.

Source contributions of urban PM2.5 in the Beijing-Tianjin-Hebei region: Changes between 2006 and 2013 and relative impacts of emissions and meteorology

NASA Astrophysics Data System (ADS)

Li, Xin; Zhang, Qiang; Zhang, Yang; Zheng, Bo; Wang, Kai; Chen, Ying; Wallington, Timothy J.; Han, Weijian; Shen, Wei; Zhang, Xiaoye; He, Kebin

2015-12-01

Anthropogenic emissions in China have been controlled for years to improve ambient air quality. However, severe haze events caused by atmospheric aerosols with aerodynamic diameter less than or equal to 2.5 μm (PM2.5) have continued to occur, especially in the Beijing-Tianjin-Hebei (BTH) region. The Chinese government has set an ambitious goal to reduce urban PM2.5 concentrations by 25% in BTH by 2017 relative to the 2012 levels. Source apportionment (SA) is necessary to the development of the effective emission control strategies. In this work, the Comprehensive Air Quality Model with extensions (CAMx) with the Particulate Source Apportionment Technology (PSAT) is applied to the China domain for the years 2006 and 2013. Ambient surface concentrations of PM2.5 and its components are generally well reproduced. To quantify the contributions of each emission category or region to PM2.5 in BTH, the total emissions are divided into 7 emission categories and 11 source regions. The source contributions determined in this work are generally consistent with results from previous work. In 2013, the industrial (44%) and residential (27%) sectors are the dominant contributors to urban PM2.5 in BTH. The residential sector is the largest contributor in winter; the industry sector dominates in other seasons. A slight increasing trend (+3% for industry and +6% for residential) is found in 2013 relative to 2006, necessitating more attention to these two sectors. Local emissions make the largest contribution (40%-60%) for all receptors. Change of source contribution of PM2.5 in Beijing and northern Hebei are dominate by change of local emission. However, for Tianjin, and central and southern Hebei, change of meteorology condition are as important as change of emission, because regional inflow in these areas is more important than in Beijing and northern Hebei and can increase under unfavorable weather conditions, indicating a strong need for regional joint emission control efforts. The results in this study enhance the quantitative understanding of the source-receptor relationships and provide an important basis for policymaking to advance the control of PM2.5 pollution in China.

Source Contributions of Urban PM2.5 in the Beijing-Tianjin-Hebei Region: Changes between 2006 and 2013 and Relative Impacts of Emissions and Meteorology

NASA Astrophysics Data System (ADS)

Li, X.; Zhang, Q.; Zhang, Y.; Zheng, B.; Li, M.; Wang, K.; Chen, Y.; Wallington, T. J.; Han, W.; Shen, W.; Zhang, X.; He, K.

2015-12-01

Anthropogenic emissions in China have been controlled for years to improve ambient air quality. However, severe haze events caused by atmospheric aerosols with aerodynamic diameter less than or equal to 2.5 μm (PM2.5) have continued to occur, especially in the Beijing-Tianjin-Hebei (BTH) region. The Chinese government has set an ambitious goal to reduce urban PM2.5 concentrations by 25% in BTH by 2017 relative to the 2012 levels. Source apportionment (SA) is necessary to the development of the effective emission control strategies. In this work, the Comprehensive Air Quality Model with extensions (CAMx) with the Particulate Source Apportionment Technology (PSAT) is applied to the China domain for the years 2006 and 2013. Ambient surface concentrations of PM2.5 and its components are generally well reproduced. To quantify the contributions of each emission category or region to PM2.5 in BTH, the total emissions are divided into 7 emission categories and 11 source regions. The source contributions determined in this work are generally consistent with results from previous work. In 2013, the industrial (44%) and residential (27%) sectors are the dominant contributors to urban PM2.5 in BTH. The residential sector is the largest contributor in winter; the industry sector dominates in other seasons. A slight increasing trend (+3% for industry and +6% for residential) is found in 2013 relative to 2006, necessitating more attention to these two sectors. Local emissions make the largest contribution (40%-60%) for all receptors. Change of source contribution of PM2.5 in Beijing and northern Hebei are dominate by change of local emission. However, for Tianjin, and central and southern Hebei, change of meteorology condition are as important as change of emission, because regional inflow in these areas is more important than in Beijing and northern Hebei and can increase under unfavorable weather conditions, indicating a strong need for regional joint emission control efforts. The results in this study enhance the quantitative understanding of the source-receptor relationships and provide an important basis for policymaking to advance the control of PM2.5 pollution in China. Both sector-based and fuel-based source apportionment will be available to further improve the comparability with receptor model results.

Reduction on NOx emissions on urban areas by changing specific vehicle fleets: effects on NO2 and O3 concentration

NASA Astrophysics Data System (ADS)

Goncalves, M.; Jimenez, P.; Baldasano, J.

2007-12-01

The largest amount of NOx emissions in urban areas comes from on-road traffic, which is the largest contributor to urban air pollution (Colvile et al., 2001). Currently different strategies are being tested in order to reduce its effects; many of them oriented to the reduction of the unitary vehicles emissions, by alternative fuels use (such as biofuels, natural gas or hydrogen) or introduction of new technologies (such as hybrid electric vehicles or fuel cells). Atmospheric modelling permits to predict their consequences on tropospheric chemistry (Vautard et al., 2007). Hence, this work assesses the changes on NO2 and O3 concentrations when substituting a 10 per cent of the urban private cars fleets by petrol hybrid electric cars (HEC) or by natural gas cars (NGC) in Madrid and Barcelona urban areas (Spain). These two cities are selected in order to highlight the different patterns of pollutants transport (inland vs. coastal city) and the different responses to emissions reductions. The results focus on a typical summertime episode of air pollution, by means of the Eulerian air quality model ARW- WRF/HERMES/CMAQ, applied with high resolution (1-hr, 1km2) since of the complexity of both areas under study. The detailed emissions scenarios are implemented in the HERMES traffic emissions module, based on the Copert III-EEA/EMEP-CORINAIR (Nztiachristos and Samaras, 2000) methodology. The HEC introduction reduces NOx emissions from on-road traffic in a 10.8 per cent and 8.2 per cent; and the NGC introduction in a 10.3 per cent and 7.8 per cent, for Madrid and Barcelona areas, respectively. The scenarios also affect the NMVOCs reduction (ranging from -3.1 to -6.9 per cent), influencing the tropospheric photochemistry through the NOx/NMVOCs ratio. The abatement of the NO photooxidation but also to the reduction on primary NO2 involves a decrease on NO2 levels centred on urban areas. For example, the NO2 24-hr average concentration in downtown areas reduces up to 8 per cent (-6 μg m-3 on average). The urban areas are VOC-controlled, therefore the reduction on NOx emissions involves a minor increase on tropospheric O3 concentration (Jiménez and Baldasano, 2004), up to 1.5 per cent at some points. Nevertheless, the O3 precursors reduction has positive effects in the downwind areas affected by the urban plume, slightly reducing the O3 levels, but at the regional scale the reduction applied on urban traffic emissions has negligible effects. Both scenarios tested are very similar in terms of emissions reductions and air quality changes, which means that the NOx/NMVOCs ratio do not involve an O3-sensitivity regime variation among scenarios. The HEC scenario is more effective in reducing NO2 levels in urban areas than the NGC scenario (with maximum reductions affecting a larger area) and involves a larger increase in urban O3 concentration.

Urbanization and carbon dioxide emissions in Singapore: evidence from the ARDL approach.

PubMed

Ali, Hamisu Sadi; Abdul-Rahim, A S; Ribadu, Mohammed Bashir

2017-01-01

The main aim of this article is to examine empirically the impact of urbanization on carbon dioxide emissions in Singapore from 1970 to 2015. The autoregressive distributed lags (ARDL) approach is applied within the analysis. The main finding reveals a negative and significant impact of urbanization on carbon emissions in Singapore, which means that urban development in Singapore is not a barrier to the improvement of environmental quality. Thus, urbanization enhances environmental quality by reducing carbon emissions in the sample country. The result also highlighted that economic growth has a positive and significant impact on carbon emissions, which suggests that economic growth reduces environmental quality through its direct effect of increasing carbon emissions in the country. Despite the high level of urbanization in Singapore, which shows that 100 % of the populace is living in the urban center, it does not lead to more environmental degradation. Hence, urbanization will not be considered an obstacle when initiating policies that will be used to reduce environmental degradation in the country. Policy makers should consider the country's level of economic growth instead of urbanization when formulating policies to reduce environmental degradation, due to its direct impact on increasing carbon dioxide emissions.

Health impacts of frequent heavy automobile traffic on children and adolescents.

PubMed

Akpan, Akpan I

2004-01-01

This paper assesses the extent to which particulate, elemental and organic carbon emissions from heavy traffic in urban city roads affect the health of children and the adolescent health. Although the health effects of exposures may be cumulative, it is in the adolescence that the manifestations are realized. This paper therefore, assesses the best way forward for monitoring and preventing the environmental health impacts of heavy traffic on children and adolescents who live within the vicinity of urban city transportation systems. Major urban cities such as Houston, New York, and California are cited as examples of cities where health-related problems have already been reported. The particulate, elemental and organic carbon emissions are reviewed as the sources by which heavy traffic and the hazardous chemical emissions affect the health of the populace. The role of accessory loading and engine speed on idling emissions in direct health risks of children and adolescents is evaluated. The association of particulate, elemental, and organic carbon emission with respiratory effects (including, allergies and asthma), and the related behavior problems in children and the adolescents are discussed. The best strategies in preventing the effects of heavy traffic in the urban cities are suggested by introducing new effective monitoring techniques and exposure assessment methods. It is visualized that a more comprehensive research is needed to develop robust regulatory systems that would control the efficiency of automobiles and prevent the adverse health effects relating to heavy traffics in urban city roads. Strong city environmental health authorities-community partnerships relevant to exposure information should be encouraged.

Source apportionment and water solubility of metals in size segregated particles in urban environments.

PubMed

Jiang, Sabrina Yanan; Kaul, Daya S; Yang, Fenhuan; Sun, Li; Ning, Zhi

2015-11-15

Metals in atmospheric particulate matter (PM) have been associated with various adverse health effects. Different factors contributing to the characterization and distribution of atmospheric metals in urban environments lead to uncertainty of the understanding of their impact on public health. However, few studies have provided a comprehensive picture of the spatial and seasonal variability of metal concentration, solubility and size distribution, all of which have important roles in their contribution to health effects. This study presents an experimental investigation on the characteristics of metals in PM2.5 and coarse PM in two seasons from four urban sites in Hong Kong. The PM samples were extracted separately with aqua regia and water, and a total of sixteen elements were analyzed using ICP-MS and ICP-OES to determine the size segregated concentration and solubility of metals. The concentrations of major metals were distributed in similar patterns with the same order of magnitude among different urban sites. Source apportionment using Positive Matrix Factorization (PMF) indicated that three sources namely road dust, vehicular exhaust and ship emission are major contributors to the urban atmospheric metal concentrations in Hong Kong with distinctly different profiles between coarse PM and PM2.5 fractions. The individual metals were assigned to different sources, consistent with literature documentation, except potassium emerging with substantial contribution from vehicle exhaust emission. Literature data from past studies on both local and other cities were compared to the results from the present study to investigate the impact of different emission sources and control policies on metal distribution in urban atmosphere. A large variation of solubility among the metals reflected that the majority of metals in PM2.5 were more soluble than those in coarse PM indicating size dependent chemical states of metals. The data from this study provides a rich dataset of metals in urban atmosphere and can be useful for targeted emission control to mitigate the adverse impact of metallic pollution on public health. Copyright © 2015 Elsevier B.V. All rights reserved.

Impact of economic growth, nonrenewable and renewable energy consumption, and urbanization on carbon emissions in Sub-Saharan Africa.

PubMed

Hanif, Imran

2018-05-01

The present study explores the impact of economic growth; urban expansion; and consumption of fossil fuels, solid fuels, and renewable energy on environmental degradation in developing economies of Sub-Saharan Africa. To demonstrate its findings in detail, the study adopts a system generalized method of moment (GMM) on a panel of 34 emerging economies for the period from 1995 to 2015. The results describe that the consumption of fossil and solid fuels for cooking and expansion of urban areas are significantly contributing to carbon dioxide emissions, on one end, and stimulating air pollution, on the other. The results also exhibit an inverted U-shape relationship between per capita economic growth and carbon emissions. This relation confirms the existence of an environmental Kuznets curve (EKC) in middle- and low-income economies of Sub-Saharan Africa. Furthermore, the findings reveal that the use of renewable energy alternatives improves air quality by controlling carbon emissions and lowering the direct interaction of households with toxic gases. Thus, the use of renewable energy alternatives helps the economies to achieve sustainable development targets.

Response surface modeling-based source contribution analysis and VOC emission control policy assessment in a typical ozone-polluted urban Shunde, China.

PubMed

You, Zhiqiang; Zhu, Yun; Jang, Carey; Wang, Shuxiao; Gao, Jian; Lin, Che-Jen; Li, Minhui; Zhu, Zhenghua; Wei, Hao; Yang, Wenwei

2017-01-01

To develop a sound ozone (O 3 ) pollution control strategy, it is important to well understand and characterize the source contribution due to the complex chemical and physical formation processes of O 3 . Using the "Shunde" city as a pilot summer case study, we apply an innovative response surface modeling (RSM) methodology based on the Community Multi-Scale Air Quality (CMAQ) modeling simulations to identify the O 3 regime and provide dynamic analysis of the precursor contributions to effectively assess the O 3 impacts of volatile organic compound (VOC) control strategy. Our results show that Shunde is a typical VOC-limited urban O 3 polluted city. The "Jiangmen" city, as the main upper wind area during July 2014, its VOCs and nitrogen oxides (NO x ) emissions make up the largest contribution (9.06%). On the contrary, the contribution from local (Shunde) emission is lowest (6.35%) among the seven neighbor regions. The local VOCs industrial source emission has the largest contribution comparing to other precursor emission sectors in Shunde. The results of dynamic source contribution analysis further show that the local NO x control could slightly increase the ground O 3 under low (10.00%) and medium (40.00%) reduction ratios, while it could start to turn positive to decrease ground O 3 under the high NO x abatement ratio (75.00%). The real-time assessment of O 3 impacts from VOCs control strategies in Pearl River Delta (PRD) shows that the joint regional VOCs emission control policy will effectively reduce the ground O 3 concentration in Shunde. Copyright © 2016. Published by Elsevier B.V.

CH4 concentrations and fluxes in a subtropical metropolitan river network: Watershed urbanization impacts and environmental controls.

PubMed

Wang, Xiaofeng; He, Yixin; Chen, Huai; Yuan, Xingzhong; Peng, Changhui; Yue, Junsheng; Zhang, Qiaoyong; Zhou, Lilei

2018-05-01

Urbanization and greenhouse gas emissions are of great global concern, especially in developing countries such as China. However, little is known about the relationship between the two. In this study, we examined the influences of the urbanization of Chongqing Municipality, which covers an area of 5494km 2 , in China, on the CH 4 emissions of in its metropolitan river network. The results from 84 sampling locations showed an overall mean CH 4 concentration of 0.69±1.37μmol·L -1 and a CH 4 flux from the river network of 1.40±2.53mmolCH 4 m -2 d -1 . The CH 4 concentrations and fluxes presented a clear seasonal pattern, with the highest value in the spring and the lowest in the summer. Such seasonal variations were probably co-regulated by the dilution effect, temperature and supply of fresh organic matter by algal blooms. Another important result was that the CH 4 concentrations and fluxes increased with the degree of urbanization or the proportion of urban land use, being approximately 3-13 times higher in urban and suburban areas than in rural ones. The total nitrogen, dissolved oxygen (O%) and possible sewage discharge, which could affect the in situ CH 4 production and exogenous CH 4 input respectively, were important factors that influenced the spatial patterns of CH 4 in human-dominated river networks, while the nitrogen (N) and phosphorus (P) could be good predictors of the CH 4 emissions in urban watersheds. Hydrologic drivers, including bottom sediment type, flow velocity and river width, were strongly correlated with the CH 4 concentrations and could also affect the spatial variance and predict the CH 4 hotspots in such metropolitan river networks. With increasing urbanization, we should pay more attention to the increasing greenhouse gas emissions associated with urbanization. Copyright © 2017 Elsevier B.V. All rights reserved.

75 FR 522 - National Emission Standards for Hazardous Air Pollutants: Area Source Standards for Prepared...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-05

... to what constitutes the generally available control technology or management practices for the area... area sources, pose the greatest threat to public health in the largest number of urban areas. EPA implemented this provision in 1999 in the Integrated Urban Air Toxics Strategy, (64 FR 38715, July 19, 1999...

Characteristics of typical non-road machinery emissions in China by using portable emission measurement system.

PubMed

Fu, Mingliang; Ge, Yunshan; Tan, Jianwei; Zeng, Tao; Liang, Bin

2012-10-15

Non-road machinery, especially construction equipment could be an important pollutant source of the deterioration in air quality in Chinese urban areas due to its large quantity and to the absence of stringent emission requirements. In this study, emission tests were performed on 12 excavators and 8 wheel loaders by using portable emission measurement system (PEMS) to determine their emission characteristics. The typical operating modes were categorized as idling mode, moving mode and working mode. Compared with those during idling and moving modes, the average time-based emission factors during working mode of HC were 2.61 and 1.27 times higher, NO(x) were 3.66 and 1.36 times higher, and PM were 4.05 and 1.95 times higher, respectively. Under all conditions, categories of the measured emissions increased with the rise in engine power. Compared with those of Stage I emission standard equipment, gaseous emissions and PM emitted from Stage II emission standard equipment were lower. The results indicated that, from Stage I to Stage II, the average reductions of HC, NO(x) and PM were 56%, 37% and 29% for the working mode, respectively. Those results also demonstrated the effectiveness of emission control regulation and the improvement of emission control technology. The data and tests show that the longer the accumulated working hours, the higher HC and NO(x) average fuel-based emission factors are. The emissions measured from the construction vehicles employed in this study were higher than the data collected in previous studies, which shows that it is critical for the government to put into effect more stringent emission regulations to further improve the air quality in Chinese urban areas. Copyright © 2012 Elsevier B.V. All rights reserved.

40 CFR 86.115-00 - EPA dynamometer driving schedules.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1977 and Later Model Year New Light-Duty Vehicles and New Light-Duty Trucks and New Otto-Cycle... for the EPA Urban Dynamometer Driving Schedule, US06, SC03, and the EPA New York City Cycles are...

40 CFR 86.115-00 - EPA dynamometer driving schedules.

Code of Federal Regulations, 2013 CFR

2013-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1977 and Later Model Year New Light-Duty Vehicles and New Light-Duty Trucks and New Otto-Cycle... for the EPA Urban Dynamometer Driving Schedule, US06, SC03, and the EPA New York City Cycles are...

40 CFR 86.115-00 - EPA dynamometer driving schedules.

Code of Federal Regulations, 2011 CFR

2011-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1977 and Later Model Year New Light-Duty Vehicles and New Light-Duty Trucks and New Otto-Cycle... for the EPA Urban Dynamometer Driving Schedule, US06, SC03, and the EPA New York City Cycles are...

40 CFR 86.115-00 - EPA dynamometer driving schedules.

Code of Federal Regulations, 2012 CFR

2012-07-01

... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1977 and Later Model Year New Light-Duty Vehicles and New Light-Duty Trucks and New Otto-Cycle... for the EPA Urban Dynamometer Driving Schedule, US06, SC03, and the EPA New York City Cycles are...

The 1977 emissions inventory for southeastern Virginia. [environment model of air quality based on exhaust emission from urban areas

NASA Technical Reports Server (NTRS)

Brewer, D. A.; Remsberg, E. E.; Woodbury, G. E.; Quinn, L. C.

1979-01-01

Regional tropospheric air pollution modeling and data compilation to simulate the time variation of species concentrations in and around an urban area is discussed. The methods used to compile an emissions inventory are outlined. Emissions factors for vehicular travel in the urban area are presented along with an analysis of the emission gases. Emission sources other than vehicular including industrial wastes, residential solid waste disposal, aircraft emissions, and emissions from the railroads are investigated.

Working Toward Policy-Relevant Air Quality Emissions Scenarios

NASA Astrophysics Data System (ADS)

Holloway, T.

2010-12-01

Though much work has been done to develop accurate chemical emission inventories, few publicly available inventories are appropriate for realistic policy analysis. Emissions from the electricity and transportation sectors, in particular, respond in complex ways to policy, technology, and energy use change. Many widely used inventories, such as the EPA National Emissions Inventory, are well-suited for modeling current air quality, but do not have the specificity needed to address "what if?" questions. Changes in electricity demand, fuel prices, new power sources, and emission controls all influence the emissions from regional power production, requiring a plant-by-plant assessment to capture the spatially explicit impacts. Similarly, land use, freight distribution, or driving behavior will yield differentiated transportation emissions for urban areas, suburbs, and rural highways. We here present results from three recent research projects at the University of Wisconsin—Madison, where bottom-up emission inventories for electricity, freight transport, and urban vehicle use were constructed to support policy-relevant air quality research. These three studies include: 1) Using the MyPower electricity dispatch model to calculate emissions and air quality impacts of Renewable Portfolio Standards and other carbon-management strategies; 2) Using advanced vehicle and commodity flow data from the Federal Highway Administration to evaluate the potential to shift commodities from truck to rail (assuming expanded infrastructure), and assess a range of alternative fuel suggestions; and 3) Working with urban planners to connect urban density with vehicle use to evaluate the air quality impacts of smart-growth in major Midwest cities. Drawing on the results of these three studies, and on challenges overcome in their execution, we discuss the current state of policy-relevant emission dataset generation, as well as techniques and attributes that need to be further refined in order to meet the increasingly intricate demands of both advanced air quality models and more realistic and relevant policy scenarios.

Long-term urban carbon dioxide observations reveal spatial and temporal dynamics related to urban characteristics and growth

DOE PAGES

Mitchell, Logan E.; Lin, John C.; Bowling, David R.; ...

2018-03-05

Cities are concentrated areas of CO 2 emissions and have become the foci of policies for mitigation actions. However, atmospheric measurement networks suitable for evaluating urban emissions over time are scarce. Here we present a unique long-term (decadal) record of CO 2 mole fractions from five sites across Utah’s metropolitan Salt Lake Valley. We examine “excess” CO 2 above background conditions resulting from local emissions and meteorological conditions. We ascribe CO 2 trends to changes in emissions, since we did not find longterm trends in atmospheric mixing proxies. Three contrasting CO 2 trends emerged across urban types: negative trends atmore » a residentialindustrial site, positive trends at a site surrounded by rapid suburban growth, and relatively constant CO 2 over time at multiple sites in the established, residential, and commercial urban core. Analysis of populationwithin the atmospheric footprints of the different sites reveals approximately equal increases in population influencing the observed CO 2, implying a nonlinear relationshipwith CO 2 emissions: Population growth in rural areas that experienced suburban development was associated with increasing emissions while population growth in the developed urban core was associated with stable emissions. Four state-of-the-art global-scale emission inventories also have a nonlinear relationship with population density across the city; however, in contrast to our observations, they all have nearly constant emissions over time. Our results indicate that decadal scale changes in urban CO 2 emissions are detectable through monitoring networks and constitute a valuable approach to evaluate emission inventories and studies of urban carbon cycles.« less

Long-term urban carbon dioxide observations reveal spatial and temporal dynamics related to urban characteristics and growth

NASA Astrophysics Data System (ADS)

Mitchell, Logan E.; Lin, John C.; Bowling, David R.; Pataki, Diane E.; Strong, Courtenay; Schauer, Andrew J.; Bares, Ryan; Bush, Susan E.; Stephens, Britton B.; Mendoza, Daniel; Mallia, Derek; Holland, Lacey; Gurney, Kevin R.; Ehleringer, James R.

2018-03-01

Cities are concentrated areas of CO2 emissions and have become the foci of policies for mitigation actions. However, atmospheric measurement networks suitable for evaluating urban emissions over time are scarce. Here we present a unique long-term (decadal) record of CO2 mole fractions from five sites across Utah’s metropolitan Salt Lake Valley. We examine “excess” CO2 above background conditions resulting from local emissions and meteorological conditions. We ascribe CO2 trends to changes in emissions, since we did not find long-term trends in atmospheric mixing proxies. Three contrasting CO2 trends emerged across urban types: negative trends at a residential-industrial site, positive trends at a site surrounded by rapid suburban growth, and relatively constant CO2 over time at multiple sites in the established, residential, and commercial urban core. Analysis of population within the atmospheric footprints of the different sites reveals approximately equal increases in population influencing the observed CO2, implying a nonlinear relationship with CO2 emissions: Population growth in rural areas that experienced suburban development was associated with increasing emissions while population growth in the developed urban core was associated with stable emissions. Four state-of-the-art global-scale emission inventories also have a nonlinear relationship with population density across the city; however, in contrast to our observations, they all have nearly constant emissions over time. Our results indicate that decadal scale changes in urban CO2 emissions are detectable through monitoring networks and constitute a valuable approach to evaluate emission inventories and studies of urban carbon cycles.

Long-term urban carbon dioxide observations reveal spatial and temporal dynamics related to urban characteristics and growth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mitchell, Logan E.; Lin, John C.; Bowling, David R.

Cities are concentrated areas of CO 2 emissions and have become the foci of policies for mitigation actions. However, atmospheric measurement networks suitable for evaluating urban emissions over time are scarce. Here we present a unique long-term (decadal) record of CO 2 mole fractions from five sites across Utah’s metropolitan Salt Lake Valley. We examine “excess” CO 2 above background conditions resulting from local emissions and meteorological conditions. We ascribe CO 2 trends to changes in emissions, since we did not find longterm trends in atmospheric mixing proxies. Three contrasting CO 2 trends emerged across urban types: negative trends atmore » a residentialindustrial site, positive trends at a site surrounded by rapid suburban growth, and relatively constant CO 2 over time at multiple sites in the established, residential, and commercial urban core. Analysis of populationwithin the atmospheric footprints of the different sites reveals approximately equal increases in population influencing the observed CO 2, implying a nonlinear relationshipwith CO 2 emissions: Population growth in rural areas that experienced suburban development was associated with increasing emissions while population growth in the developed urban core was associated with stable emissions. Four state-of-the-art global-scale emission inventories also have a nonlinear relationship with population density across the city; however, in contrast to our observations, they all have nearly constant emissions over time. Our results indicate that decadal scale changes in urban CO 2 emissions are detectable through monitoring networks and constitute a valuable approach to evaluate emission inventories and studies of urban carbon cycles.« less

[Odor pollution from landfill sites and its control: a review].

PubMed

Hu, Bin; Ding, Ying; Wu, Wei-Xiang; Hu, Bei-Gang; Chen, Ying-Xu

2010-03-01

Landfill sites are the major sources of offensive odor in urban public facilities. With the progress of urbanization and the residents' demands for a higher living environment quality, the odor emission from landfill sites has become a severe pollution problem, and the odor control at landfill sites has been one of the research hotspots. This paper summarized the main components and their concentrations of the odor from landfill sites, and expatiated on the research progress in the in-situ control of the odor. The further research directions in in-situ control of the odor from landfill sites were prospected.

Soil greenhouse gas emissions and carbon budgeting in a short-hydroperiod floodplain wetland

NASA Astrophysics Data System (ADS)

Batson, Jackie; Noe, Gregory B.; Hupp, Cliff R.; Krauss, Ken W.; Rybicki, Nancy B.; Schenk, Edward R.

2015-01-01

Understanding the controls on floodplain carbon (C) cycling is important for assessing greenhouse gas emissions and the potential for C sequestration in river-floodplain ecosystems. We hypothesized that greater hydrologic connectivity would increase C inputs to floodplains that would not only stimulate soil C gas emissions but also sequester more C in soils. In an urban Piedmont river (151 km2 watershed) with a floodplain that is dry most of the year, we quantified soil CO2, CH4, and N2O net emissions along gradients of floodplain hydrologic connectivity, identified controls on soil aerobic and anaerobic respiration, and developed a floodplain soil C budget. Sites were chosen along a longitudinal river gradient and across lateral floodplain geomorphic units (levee, backswamp, and toe slope). CO2 emissions decreased downstream in backswamps and toe slopes and were high on the levees. CH4 and N2O fluxes were near zero; however, CH4 emissions were highest in the backswamp. Annual CO2 emissions correlated negatively with soil water-filled pore space and positively with variables related to drier, coarser soil. Conversely, annual CH4 emissions had the opposite pattern of CO2. Spatial variation in aerobic and anaerobic respiration was thus controlled by oxygen availability but was not related to C inputs from sedimentation or vegetation. The annual mean soil CO2 emission rate was 1091 g C m-2 yr-1, the net sedimentation rate was 111 g C m-2 yr-1, and the vegetation production rate was 240 g C m-2 yr-1, with a soil C balance (loss) of -338 g C m-2 yr-1. This floodplain is losing C likely due to long-term drying from watershed urbanization.

The inhabited environment, infrastructure development and advanced urbanization in China’s Yangtze River Delta Region

NASA Astrophysics Data System (ADS)

Zhu, Xiaoqing; Gao, Weijun; Zhou, Nan; Kammen, Daniel M.; Wu, Yiqun; Zhang, Yao; Chen, Wei

2016-12-01

This paper analyzes the relationship among the inhabited environment, infrastructure development and environmental impacts in China’s heavily urbanized Yangtze River Delta region. Using primary human environment data for the period 2006-2014, we examine factors affecting the inhabited environment and infrastructure development: urban population, GDP, built-up area, energy consumption, waste emission, transportation, real estate and urban greenery. Then we empirically investigate the impact of advanced urbanization with consideration of cities’ differences. Results from this study show that the growth rate of the inhabited environment and infrastructure development is strongly influenced by regional development structure, functional orientations, traffic network and urban size and form. The effect of advanced urbanization is more significant in large and mid-size cities than huge and mega cities. Energy consumption, waste emission and real estate in large and mid-size cities developed at an unprecedented rate with the rapid increase of economy. However, urban development of huge and mega cities gradually tended to be saturated. The transition development in these cities improved the inhabited environment and ecological protection instead of the urban construction simply. To maintain a sustainable advanced urbanization process, policy implications included urban sprawl control polices, ecological development mechanisms and reforming the economic structure for huge and mega cities, and construct major cross-regional infrastructure, enhance the carrying capacity and improvement of energy efficiency and structure for large and mid-size cities.

PM, NOx and butane emissions from on-road vehicle fleets in Hong Kong and their implications on emission control policy

NASA Astrophysics Data System (ADS)

Ning, Zhi; Wubulihairen, Maimaitireyimu; Yang, Fenhuan

2012-12-01

Vehicular emissions are the major sources of air pollution in urban areas. For metropolitan cities with large population working and living in environments with direct traffic impact, emission control is of great significance to protect public health. Implementation of more stringent emission standards, retrofitting fleet with emission control devices and switching to clearer fuel has been commonly practiced in different cities including Hong Kong. The present study employed a new plume chasing method for effective and quick evaluation of on-road fleet emission factors of particulate matter (PM), nitrogen oxides (NOx), and butane from heavy duty diesel trucks, diesel buses and liquefied petroleum gas (LPG) vehicles. The results showed distinct profiles of the emissions from different fleets with excessive butane emissions from LPG fleet and contrasting PM and NOx emissions from diesel trucks and buses fleets. A cross comparison was also made with emission data from other cities and from historic local studies. The implications of the observed difference on the effectiveness of emission control measures and policy are discussed with recommendations of direction for future research and policy making.

Modelling study of boundary-layer ozone over northern China - Part II: Responses to emission reductions during the Beijing Olympics

NASA Astrophysics Data System (ADS)

Tang, Guiqian; Zhu, Xiaowan; Xin, Jinyuan; Hu, Bo; Song, Tao; Sun, Yang; Wang, Lili; Wu, Fangkun; Sun, Jie; Cheng, Mengtian; Chao, Na; Li, Xin; Wang, Yuesi

2017-09-01

The implementation of emission reduction measures during the Olympics provided a valuable opportunity to study regional photochemical pollution over northern China. In this study, the fifth-generation Pennsylvania State University/National Centre for Atmospheric Research Mesoscale Model and Community Multiscale Air Quality model system was applied to conduct two sets of modelling analyses of the period from July 20 to September 20, 2008, to illustrate the influences of emission reduction measures on regional photochemical pollution over northern China during the Beijing Olympics. The results indicated that the implementation of emission control measures decreased the concentrations of ozone (O3) precursors, namely nitrogen oxide (NOx) and volatile organic compounds (VOCs), throughout the boundary layer. The concentrations of these compounds were reduced by 45% in the central urban area of Beijing at the ground level. Although the average O3 concentration in the central urban area increased by more than 8 ppbv, the total oxidant concentration decreased significantly by more than 5 ppbv. Greater O3 concentrations mainly occurred during periods with weak photochemical reactions. During periods of strong photochemical production, the O3 concentration decreased significantly due to a weakening vertical circulation between the lower and upper boundary layer. Consequently, the number of days when the O3 concentration exceeded 100 ppbv decreased by 25% in Beijing. The emission control measures altered the sensitivity of the regional O3 production. The coordinated control region of NOx and VOCs expanded, and the control region of VOCs decreased in size. The reduction of non-point-source emissions, such as fugitive VOCs and vehicles, was more useful for controlling regional photochemical pollution over northern China.

Accounting for urban biogenic fluxes in regional carbon budgets.

PubMed

Hardiman, Brady S; Wang, Jonathan A; Hutyra, Lucy R; Gately, Conor K; Getson, Jackie M; Friedl, Mark A

2017-08-15

Many ecosystem models incorrectly treat urban areas as devoid of vegetation and biogenic carbon (C) fluxes. We sought to improve estimates of urban biomass and biogenic C fluxes using existing, nationally available data products. We characterized biogenic influence on urban C cycling throughout Massachusetts, USA using an ecosystem model that integrates improved representation of urban vegetation, growing conditions associated with urban heat island (UHI), and altered urban phenology. Boston's biomass density is 1/4 that of rural forests, however 87% of Massachusetts' urban landscape is vegetated. Model results suggest that, kilogram-for-kilogram, urban vegetation cycles C twice as fast as rural forests. Urban vegetation releases (R E ) and absorbs (GEE) the equivalent of 11 and 14%, respectively, of anthropogenic emissions in the most urban portions of the state. While urban vegetation in Massachusetts fully sequesters anthropogenic emissions from smaller cities in the region, Boston's UHI reduces annual C storage by >20% such that vegetation offsets only 2% of anthropogenic emissions. Asynchrony between temporal patterns of biogenic and anthropogenic C fluxes further constrains the emissions mitigation potential of urban vegetation. However, neglecting to account for biogenic C fluxes in cities can impair efforts to accurately monitor, report, verify, and reduce anthropogenic emissions. Copyright © 2017 Elsevier B.V. All rights reserved.

The role of population density on the impact of urbaniza-tion on GHG emissions in China

NASA Astrophysics Data System (ADS)

Liu, Yonghong; Gao, Chaochao; Lu, Yingying

2017-04-01

Urbanization directly drives rural to urban population migration and indirectly causes west to east migration in China, two phenomena that may significantly impact China's greenhouse gas emissions given its huge population and vast difference between the western rural and eastern urban areas. These two phenomena were analyzed by using emissions as a per capita term, and extending the impact from the traditional urbanization rate effect to include population density effect. The results show that population density has actually been the dominant demographic player in changing per capita emissions for the past two decades in China, and its elasticity changed from positive in economically less-developed provinces to negative for the developed provinces. This study provides a new perspective in the study of the relationship between urbanization and greenhouse gas emissions, and the results indicate that population density change should be taken into account to accurately assess the impact of urbanization.

Impact of traffic volume and composition on the air quality and pedestrian exposure in urban street canyon

NASA Astrophysics Data System (ADS)

Rakowska, Agata; Wong, Ka Chun; Townsend, Thomas; Chan, Ka Lok; Westerdahl, Dane; Ng, Simon; Močnik, Griša; Drinovec, Luka; Ning, Zhi

2014-12-01

Vehicle emissions are identified as a major source of air pollution in metropolitan areas. Emission control programs in many cities have been implemented as part of larger scale transport policy interventions to control traffic pollutants and reduce public health risks. These interventions include provision of traffic-free and low emission zones and congestion charging. Various studies have investigated the impact of urban street configurations, such as street canyon in urban centers, on pollutants dispersion and roadside air quality. However, there are few investigations in the literature to study the impact of change of fleet composition and street canyon effects on the on-road pollutants concentrations and associated roadside pedestrian exposure to the pollutants. This study presents an experimental investigation on the traffic related gas and particle pollutants in and near major streets in one of the most developed business districts in Hong Kong, known as Central. Both street canyon and open roadway configurations were included in the study design. Mobile measurement techniques were deployed to monitor both on-road and roadside pollutants concentrations at different times of the day and on different days of a week. Multiple traffic counting points were also established to concurrently collect data on traffic volume and fleet composition on individual streets. Street canyon effects were evident with elevated on-road pollutants concentrations. Diesel vehicles were found to be associated with observed pollutant levels. Roadside black carbon concentrations were found to correlate with their on-road levels but with reduced concentrations. However, ultrafine particles showed very high concentrations in roadside environment with almost unity of roadside/on-road ratios possibly due to the accumulation of primary emissions and secondary PM formation. The results from the study provide useful information for the effective urban transport design and bus route reorganization to minimize the impact of traffic emissions on the urban air quality and public health. Observations on the elevated ultrafine particle concentrations in roadside pedestrian levels also demonstrate the urgent need to improve roadside air quality to reduce pedestrians' health risks especially inside street canyon.

Photosynthesis and isoprene emission from trees along an urban-rural gradient in Texas.

PubMed

Lahr, Eleanor C; Schade, Gunnar W; Crossett, Caitlin C; Watson, Matthew R

2015-11-01

Isoprene emission is an important mechanism for improving the thermotolerance of plant photosystems as temperatures increase. In this study, we measured photosynthesis and isoprene emission in trees along an urban-rural gradient that serves as a proxy for climate change, to understand daily and seasonal responses to changes in temperature and other environmental variables. Leaf-level gas exchange and basal isoprene emission of post oak (Quercus stellata) and sweet gum (Liquidambar styraciflua) were recorded at regular intervals over an entire growing season at urban, suburban, and rural sites in eastern Texas. In addition, the temperature and atmospheric carbon dioxide concentration experienced by leaves were experimentally manipulated in spring, early summer, and late summer. We found that trees experienced lower stomatal conductance and photosynthesis and higher isoprene emission, at the urban and suburban sites compared to the rural site. Path analysis indicated a daily positive effect of isoprene emission on photosynthesis, but unexpectedly, higher isoprene emission from urban trees was not associated with improved photosynthesis as temperatures increased during the growing season. Furthermore, urban trees experienced relatively higher isoprene emission at high CO2 concentrations, while isoprene emission was suppressed at the other sites. These results suggest that isoprene emission may be less beneficial in urban, and potentially future, environmental conditions, particularly if higher temperatures override the suppressive effects of high CO2 on isoprene emission. These are important considerations for modeling future biosphere-atmosphere interactions and for understanding tree physiological responses to climate change. © 2015 John Wiley & Sons Ltd.

The impact of urbanization on CO2 emissions in China: an empirical study using 1980-2014 provincial data.

PubMed

Wang, Shijin; Li, Cunfang

2018-01-01

Towns and cities are not only the focus of attention for their consumption of energy and resources; they are also scrutinized closely for their emissions of greenhouse gases. China's urbanization level now exceeds 50%, but there is still much disparity compared with the level of urbanization in developed countries. This study selects China's urban population and carbon emissions data for the years 1980-2014 and discusses the timing and cause effect of urbanization and the corresponding carbon emissions using the Granger causality test and an error correction model (ECM) then uses STIRPAT models to extract six indicators to measure the quality of urbanization, namely, the level of urbanization, area of built-up regions, added value of tertiary industries, disposable income per capita, green areas per capita, and energy intensity. These six indicators represent population agglomeration, the expansion of urban areas, industrial agglomeration, quality of life improvements, ecological conservation, and technological improvements, respectively. The study divides 29 provinces in China into three groups based on the quality of urbanization and analyzes the impacts of the six indicators of urbanization quality on carbon emissions. The findings show that the impacts of different factors on carbon emissions vary substantially among the provinces. Finally, the study uses the findings to give suggestions on how to develop low-carbon urbanization.

Is it time to tackle PM(2.5) air pollutions in China from biomass-burning emissions?

PubMed

Zhang, Yan-Lin; Cao, Fang

2015-07-01

An increase in haze days has been observed in China over the past two decades due to the rapid industrialization, urbanization and energy consumptions. To address this server issue, Chinese central government has recently released the Action Plan on Prevention and Control of Air Pollution, which mainly focuses on regulation of indusial and transport-related emissions with major energy consumption from fossil fuels. This comprehensive and toughest plan is definitely a major step in the right direction aiming at beautiful and environmental-friendly China; however, based on recent source apportionment results, we suggest that strengthening regulation emissions from biomass-burning sources in both urban and rural areas is needed to meet a rigorous reduction target. Here, household biofuel and open biomass burning are highlighted, as impacts of these emissions can cause local and regional pollution. Copyright © 2015 Elsevier Ltd. All rights reserved.

Resolving the interactions between population density and air pollution emissions controls in the San Joaquin Valley, USA.

PubMed

Hixson, Mark; Mahmud, Abdullah; Hu, Jianlin; Kleeman, Michael J

2012-05-01

The effectiveness of emissions control programs designed to reduce concentrations of airborne particulate matter with an aerodynamic diameter < 2.5 microm (PM2.5) in California's San Joaquin Valley was studied in the year 2030 under three growth scenarios: low, medium, and high population density. Base-case inventories for each choice of population density were created using a coupled emissions modeling system that simultaneously considered interactions between land use and transportation, area source, and point source emissions. The ambient PM2.5 response to each combination of population density and emissions control was evaluated using a regional chemical transport model over a 3-week winter stagnation episode. Comparisons between scenarios were based on regional average and population-weighted PM2.5 concentrations. In the absence of any emissions control program, population-weighted concentrations of PM2.5 in the future San Joaquin Valley are lowest undergrowth scenarios that emphasize low population density. A complete ban on wood burning and a 90% reduction in emissions from food cooking operations and diesel engines must occur before medium- to high-density growth scenarios result in lower population-weighted concentrations of PM2.5. These trends partly reflect the fact that existing downtown urban cores that naturally act as anchor points for new high-density growth in the San Joaquin Valley are located close to major transportation corridors for goods movement. Adding growth buffers around transportation corridors had little impact in the current analysis, since the 8-km resolution of the chemical transport model already provided an artificial buffer around major emissions sources. Assuming that future emissions controls will greatly reduce or eliminate emissions from residential wood burning, food cooking, and diesel engines, the 2030 growth scenario using "as-planned" (medium) population density achieves the lowest population-weighted average PM2.5 concentration in the future San Joaquin Valley during a severe winter stagnation event. The San Joaquin Valley is one of the most heavily polluted air basins in the United States that are projected to experience strong population growth in the coming decades. The best plan to improve air quality in the region combines medium- or high-density population growth with rigorous emissions controls. In the absences of controls, high-density growth leads to increased population exposure to PM2.5 compared with low-density growth scenarios (urban sprawl).

Effects of a holiday week on urban soil CO2 flux: an intensive study in Xiamen, southeastern China

NASA Astrophysics Data System (ADS)

Ye, H.; Wang, K.; Chen, F.

2012-12-01

To study the effects of a holiday period on urban soil CO2 flux, CO2 efflux from grassland soil in a traditional park in the city of Xiamen was measured hourly from 28th Sep to 11th Oct, a period that included China's National Day holiday week in 2009. The results of this study revealed that: a) The urban soil CO2 emissions were higher before and after the holiday week and lower during the National Day holiday reflecting changes in the traffic cycles; b) A diurnal cycle where the soil CO2 flux decreased from early morning to noon was associated with CO2 uptake by vegetation which strongly offset vehicle CO2 emissions. The soil CO2 flux increased from night to early morning, associated with reduced CO2 uptake by vegetation; c) During the National Day holiday week in 2009, lower rates of soil respiration were measured after Mid-Autumn Day than earlier in the week, and this was related to a reduced level of human activities and vehicle traffic, reducing the CO2 concentration in the air. Urban holidays have a clear effect on soil CO2 flux through the interactions between vehicle, visitor and vegetation CO2 emissions which indirectly control the use of carbon by plant roots, the rhizosphere and soil microorganisms. Consequently, appropriate traffic controls and tourism travel plans can have positive effects on the soil carbon store and may improve local air quality.

Air quality assessment of Estarreja, an urban industrialized area, in a coastal region of Portugal.

PubMed

Figueiredo, M L; Monteiro, A; Lopes, M; Ferreira, J; Borrego, C

2013-07-01

Despite the increasing concern given to air quality in urban and industrial areas in recent years, particular emphasis on regulation, control, and reduction of air pollutant emissions is still necessary to fully characterize the chain emissions-air quality-exposure-dose-health effects, for specific sources. The Estarreja region was selected as a case study because it has one of the largest chemical industrial complexes in Portugal that has been recently expanded, together with a growing urban area with an interesting location in the Portuguese coastland and crossed by important road traffic and rail national networks. This work presents the first air quality assessment for the region concerning pollutant emissions and meteorological and air quality monitoring data analysis, over the period 2000-2009. This assessment also includes a detailed investigation and characterization of past air pollution episodes for the most problematic pollutants: ozone and PM10. The contribution of different emission sources and meteorological conditions to these episodes is investigated. The stagnant meteorological conditions associated with local emissions, namely industrial activity and road traffic, are the major contributors to the air quality degradation over the study region. A set of measures to improve air quality--regarding ozone and PM10 levels--is proposed as an air quality management strategy for the study region.

Will urban expansion lead to an increase in future water pollution loads?--a preliminary investigation of the Haihe River Basin in northeastern China.

PubMed

Dong, Yang; Liu, Yi; Chen, Jining

2014-01-01

Urban expansion is a major driving force changing regional hydrology and nonpoint source pollution. The Haihe River Basin, the political, economic, and cultural center of northeastern China, has undergone rapid urbanization in recent decades. To investigate the consequences of future urban sprawl on nonpoint source water pollutant emissions in the river basin, the urban sprawl in 2030 was estimated, and the annual runoff and nonpoint source pollution in the Haihe River basin were simulated. The Integrated Model of Non-Point Sources Pollution Processes (IMPULSE) was used to simulate the effects of urban sprawl on nonpoint source pollution emissions. The outcomes indicated that the urban expansion through 2030 increased the nonpoint source total nitrogen (TN), total phosphorous (TP), and chemical oxygen demand (COD) emissions by 8.08, 0.14, and 149.57 kg/km(2), respectively. Compared to 2008, the total nonpoint emissions rose by 15.33, 0.57, and 12.39 %, respectively. Twelve percent of the 25 cities in the basin would increase by more than 50 % in nonpoint source TN and COD emissions in 2030. In particular, the nonpoint source TN emissions in Xinxiang, Jiaozuo, and Puyang would rise by 73.31, 67.25, and 58.61 %, and the nonpoint source COD emissions in these cities would rise by 74.02, 51.99, and 53.27 %, respectively. The point source pollution emissions in 2008 and 2030 were also estimated to explore the effects of urban sprawl on total water pollution loads. Urban sprawl through 2030 would bring significant structural changes of total TN, TP, and COD emissions for each city in the area. The results of this study could provide insights into the effects of urbanization in the study area and the methods could help to recognize the role that future urban sprawl plays in the total water pollution loads in the water quality management process.

Nitrogen Oxide Emission, Economic Growth and Urbanization in China: a Spatial Econometric Analysis

NASA Astrophysics Data System (ADS)

Zhou, Zhimin; Zhou, Yanli; Ge, Xiangyu

2018-01-01

This research studies the nexus of nitrogen oxide emissions and economic development/urbanization. Under the environmental Kuznets curve (EKC) hypothesis, we apply the analysis technique of spatial panel data in the STIRPAT framework, and thus obtain the estimated impacts of income/urbanization on nitrogen oxide emission systematically. The empirical findings suggest that spatial dependence on nitrogen oxide emission distribution exist at provincial level, and the inverse N-shape EKC describes both income-nitrogen oxide and urbanization-nitrogen oxide nexuses. In addition, some well-directed policy advices are made to reduce the nitrogen oxide emission in future.

Tracking Reactive Nitrogen Sources, Chemistry and Deposition in Urban Environments Using Stable Isotopes

NASA Astrophysics Data System (ADS)

Hastings, M. G.; Clark, S. C.; Chai, J.; Joyce, E.; Miller, D. J.; Schiebel, H.; Walters, W.

2017-12-01

Reactive nitrogen (Nr) includes compounds such as nitrogen oxides (NOx, HONO), ammonia (NH3), nitrate (NO3-), ammonium (NH4+), and organic nitrates. These compounds serve major roles in controlling the composition of our atmosphere, and have a direct impact on ecosystem health and water quality. Our research is focused on using stable isotopes of Nr to investigate variations in sources, chemistry, atmospheric transport, and deposition. Our aim is to fingerprint distinct emission sources - such as vehicles, power plants, aircraft, agriculature, wildfires, and lightning - and track their influence in the environment. We have recently characterized vehicle emission plumes, emissions from agricultural soils under different management practices, and (in the near future) wildfire plumes in the western U.S. Our approach targets characterizing the isotopic composition of NOx, HONO, and NH3 at both the emissions source and the plume scale. In contrast to large ranges found for individual tailpipe emissions of NOx, on-road plumes in the U.S. have a mean δ15N of -4.7 ± 1.7‰. The plume scale approach integrates across the typical U.S. fleet giving a representative value that can be used for tracking the impact of this emission source in the environment. NH3 also tends towards a narrow isotopic range when considered at the roadside scale compared to individual vehicles. In agricultural settings, the isotopes of NOx and HONO released from soils under different fertilizer practices is typically very negative in δ15N (-40 to -10‰) and appears to vary most with soil N properties rather than meteorology. Our work is now extending to discern sources influencing Nr deposition in an urban area at the head of New England's largest estuary. National monitoring of N deposition shows decreases in NO3- (but not NH4+) deposition over the last two decades, following better controls on NOx emissions. Wet deposition collected in an urban area exhibits N concentrations that are often 3-5 times higher than that found in regional monitoring networks. An event-based, year-round record of the isotopic composition of NO3- and NH4+ in wet deposition is currently underway with the aim of constraining local versus transported emissions sources and understanding the implications of very concentrated deposition events on a major urban watershed.

Decoupling emissions of greenhouse gas, urbanization, energy and income: analysis from the economy of China.

PubMed

Wang, Tianqiong; Riti, Joshua Sunday; Shu, Yang

2018-05-08

The adoption and ratification of relevant policies, particularly the household enrolment system metamorphosis in China, led to rising urbanization growth. As the leading developing economy, China has experienced a drastic and rapid increase in the rate of urbanization, energy use, economic growth and greenhouse gas (GHG) pollution for the past 30 years. The knowledge of the dynamic interrelationships among these trends has a plethora of implications ranging from demographic, energy, and environmental and sustainable development policies. This study analyzes the role of urbanization in decoupling GHG emissions, energy, and income in China while considering the critical contribution of energy use. As a contribution to the extant body of literature, the present research introduces a new phenomenon called "the environmental urbanization Kuznets curve" (EUKC), which shows that at the early stage of urbanization, the environment degrades however, after a threshold point the technique effects surface and environmental degradation reduces with rise in urbanization. Applying the autoregressive distributed lag model and the vector error correction model, the paper finds the presence of inverted U-shaped curve between urbanization and GHG emission of CO 2 , while the same hypothesis cannot be found between income and GHG emission of CO 2 . Energy use in all the models contributes to GHG emission of CO 2 . In decoupling greenhouse gas emissions, urbanization, energy, and income, articulated and well-implemented energy and urbanization policies should be considered.

Does Size Matter? Scaling of CO2 Emissions and U.S. Urban Areas

PubMed Central

Fragkias, Michail; Lobo, José; Strumsky, Deborah; Seto, Karen C.

2013-01-01

Urban areas consume more than 66% of the world’s energy and generate more than 70% of global greenhouse gas emissions. With the world’s population expected to reach 10 billion by 2100, nearly 90% of whom will live in urban areas, a critical question for planetary sustainability is how the size of cities affects energy use and carbon dioxide (CO2) emissions. Are larger cities more energy and emissions efficient than smaller ones? Do larger cities exhibit gains from economies of scale with regard to emissions? Here we examine the relationship between city size and CO2 emissions for U.S. metropolitan areas using a production accounting allocation of emissions. We find that for the time period of 1999–2008, CO2 emissions scale proportionally with urban population size. Contrary to theoretical expectations, larger cities are not more emissions efficient than smaller ones. PMID:23750213

Residential building energy conservation and avoided power plant emissions by urban and community trees in the United States

Treesearch

David J. Nowak; Nathaniel Appleton; Alexis Ellis; Eric Greenfield

2017-01-01

Urban trees and forests alter building energy use and associated emissions from power plants by shading buildings, cooling air temperatures and altering wind speeds around buildings. Field data on urban trees were combined with local urban/community tree and land cover maps, modeling of tree effects on building energy use and pollutant emissions, and state energy and...

Source data supported high resolution carbon emissions inventory for urban areas of the Beijing-Tianjin-Hebei region: Spatial patterns, decomposition and policy implications.

PubMed

Cai, Bofeng; Li, Wanxin; Dhakal, Shobhakar; Wang, Jianghao

2018-01-15

This paper developed internationally compatible methods for delineating boundaries of urban areas in China. By integrating emission source data with existing official statistics as well as using rescaling methodology of data mapping for 1 km grid, the authors constructed high resolution emission gridded data in Beijing-Tianjin-Hebei (Jing-Jin-Ji) region in China for 2012. Comparisons between urban and non-urban areas of carbon emissions from industry, agriculture, household and transport exhibited regional disparities as well as sectoral differences. Except for the Hebei province, per capita total direct carbon emissions from urban extents in Beijing and Tianjin were both lower than provincial averages, indicating the climate benefit of urbanization, comparable to results from developed countries. Urban extents in the Hebei province were mainly industrial centers while those in Beijing and Tianjin were more service oriented. Further decomposition analysis revealed population to be a common major driver for increased carbon emissions but climate implications of urban design, economic productivity of land use, and carbon intensity of GDP were both cluster- and sector-specific. This study disapproves the one-size-fits-all solution for carbon mitigation but calls for down-scaled analysis of carbon emissions and formulation of localized carbon reduction strategies in the Jing-Jin-Ji as well as other regions in China. Copyright © 2017 Elsevier Ltd. All rights reserved.

Non-agricultural ammonia emissions in urban China

NASA Astrophysics Data System (ADS)

Chang, Y. H.

2014-03-01

The non-agricultural ammonia (NH3) emissions in cities have received little attention but could rival agricultural sources in term of the efficiency in PM formation. The starting point for finding credible solutions is to comprehensively establish a city-specific Non-agricultural Ammonia Emission Inventory (NAEI) and identify the largest sources where efforts can be directed to deliver the largest impact. In this paper, I present a NAEI of 113 national key cities targeted on environmental protection in China in 2010, which for the first time covers NH3 emissions from pets, infants, smokers, green land, and household products. Results show that totally 210 478 Mg, the NH3 emissions from traffic, fuel combustion, waste disposal, pets, green land, human, and household products are 67 671 Mg, 56 275 Mg, 44 289 Mg, 23 355 Mg, 7509 Mg, 7312 Mg, and 4069 Mg, respectively. The NH3 emission intensity from the municipal districts ranges from 0.08 to 3.13 Mg km-2 yr-1, with a average of 0.84 Mg km-2 yr-1. The high NH3 emission intensities in Beijing-Tianjin-Hebei region, Yangtze River Delta region and Pearl River Delta region support the view that non-agricultural NH3 sources play a key role in city-scale NH3 emissions and thus have potentially important implications for secondary PM formation (ammonium-sulfate-nitrate system) in urban agglomeration of China. Therefore, in addition to current SO2 and NOx controls, China also needs to allocate more scientific, technical, and legal resources on controlling non-agricultural NH3 emissions in the future.

Trends of tropospheric NO2 over the Yangtze River Delta region and the possible linkage to rapid urbanization

NASA Astrophysics Data System (ADS)

Ma, Mingliang; Zhang, Deying; Liu, Qiyang; Song, Yue; Zhou, Jiayuan; Shi, Runhe; Gao, Wei

2017-09-01

Over the past decade, China has experienced a rapid increase in urbanization. The urban built-up areas (population) of Shanghai increased by 16.1% (22.9%) from 2006 to 2015. This study aims to analyze the variations of tropospheric NO2 over Yangtze River Delta region and the impacts of rapid urbanization during 2006-2015. The results indicate that tropospheric NO2 vertical column density (VCD) of all cities in the study area showed an increasing trend during 2006-2011 whereas a decreasing trend during 2011-2015. Most cities showed a lower tropospheric NO2 VCD value in 2015 compared to that in 2006, except for Changzhou and Nantong. Shanghai and Ningbo are two hotspots where the tropospheric NO2 VCD decreased most significantly, at a rate of 22% and 19%, respectively. This effect could be ascribed to the implementation of harsh emission control policies therein. Similar seasonal variability was observed over all cities, with larger values observed in the summer and smaller values shown in the winter. Further investigations show that the observed increasing trend of tropospheric NO2 during 2006-2011 could be largely explained by rapid urbanization linked to car ownership, GDP, power consumption, population and total industrial output. Such effect was not prominent after 2011, mainly due to the implementation of emission control strategies.

Modeling carbon emissions from urban traffic system using mobile monitoring.

PubMed

Sun, Daniel Jian; Zhang, Ying; Xue, Rui; Zhang, Yi

2017-12-01

Comprehensive analyses of urban traffic carbon emissions are critical in achieving low-carbon transportation. This paper started from the architecture design of a carbon emission mobile monitoring system using multiple sets of equipment and collected the corresponding data about traffic flow, meteorological conditions, vehicular carbon emissions and driving characteristics on typical roads in Shanghai and Wuxi, Jiangsu province. Based on these data, the emission model MOVES was calibrated and used with various sensitivity and correlation evaluation indices to analyze the traffic carbon emissions at microscopic, mesoscopic and macroscopic levels, respectively. The major factors that influence urban traffic carbon emissions were investigated, so that emission factors of CO, CO 2 and HC were calculated by taking representative passenger cars as a case study. As a result, the urban traffic carbon emissions were assessed quantitatively, and the total amounts of CO, CO 2 and HC emission from passenger cars in Shanghai were estimated as 76.95kt, 8271.91kt, and 2.13kt, respectively. Arterial roads were found as the primary line source, accounting for 50.49% carbon emissions. In additional to the overall major factors identified, the mobile monitoring system and carbon emission quantification method proposed in this study are of rather guiding significance for the further urban low-carbon transportation development. Copyright © 2017 Elsevier B.V. All rights reserved.

Real-world fuel efficiency and exhaust emissions of light-duty diesel vehicles and their correlation with road conditions.

PubMed

Hu, Jingnan; Wu, Ye; Wang, Zhishi; Li, Zhenhua; Zhou, Yu; Wang, Haitao; Bao, Xiaofeng; Hao, Jiming

2012-01-01

The real-world fuel efficiency and exhaust emission profiles of CO, HC and NOx for light-duty diesel vehicles were investigated. Using a portable emissions measurement system, 16 diesel taxies were tested on different roads in Macao and the data were normalized with the vehicle specific power bin method. The 11 Toyota Corolla diesel taxies have very good fuel economy of (5.9 +/- 0.6) L/100 km, while other five diesel taxies showed relatively high values at (8.5 +/- 1.7) L/100 km due to the variation in transmission systems and emission control strategies. Compared to similar Corolla gasoline models, the diesel cars confirmed an advantage of ca. 20% higher fuel efficiency. HC and CO emissions of all the 16 taxies are quite low, with the average at (0.05 +/- 0.02) g/km and (0.38 +/- 0.15) g/km, respectively. The average NOx emission factor of the 11 Corolla taxies is (0.56 +/- 0.17) g/km, about three times higher than their gasoline counterparts. Two of the three Hyundai Sonata taxies, configured with exhaust gas recirculation (EGR) + diesel oxidation catalyst (DOC) emission control strategies, indicated significantly higher NO2 emissions and NO2/NOx ratios than other diesel taxies and consequently trigger a concern of possibly adverse impacts on ozone pollution in urban areas with this technology combination. A clear and similar pattern for fuel consumption and for each of the three gaseous pollutant emissions with various road conditions was identified. To save energy and mitigate CO2 emissions as well as other gaseous pollutant emissions in urban area, traffic planning also needs improvement.

Urban emissions of water vapor in winter

NASA Astrophysics Data System (ADS)

Salmon, Olivia E.; Shepson, Paul B.; Ren, Xinrong; Marquardt Collow, Allison B.; Miller, Mark A.; Carlton, Annmarie G.; Cambaliza, Maria O. L.; Heimburger, Alexie; Morgan, Kristan L.; Fuentes, Jose D.; Stirm, Brian H.; Grundman, Robert; Dickerson, Russell R.

2017-09-01

Elevated water vapor (H2Ov) mole fractions were occasionally observed downwind of Indianapolis, IN, and the Washington, D.C.-Baltimore, MD, area during airborne mass balance experiments conducted during winter months between 2012 and 2015. On days when an urban H2Ov excess signal was observed, H2Ov emission estimates range between 1.6 × 104 and 1.7 × 105 kg s-1 and account for up to 8.4% of the total (background + urban excess) advected flow of atmospheric boundary layer H2Ov from the urban study sites. Estimates of H2Ov emissions from combustion sources and electricity generation facility cooling towers are 1-2 orders of magnitude smaller than the urban H2Ov emission rates estimated from observations. Instances of urban H2Ov enhancement could be a result of differences in snowmelt and evaporation rates within the urban area, due in part to larger wintertime anthropogenic heat flux and land cover differences, relative to surrounding rural areas. More study is needed to understand why the urban H2Ov excess signal is observed on some days, and not others. Radiative transfer modeling indicates that the observed urban enhancements in H2Ov and other greenhouse gas mole fractions contribute only 0.1°C d-1 to the urban heat island at the surface. This integrated warming through the boundary layer is offset by longwave cooling by H2Ov at the top of the boundary layer. While the radiative impacts of urban H2Ov emissions do not meaningfully influence urban heat island intensity, urban H2Ov emissions may have the potential to alter downwind aerosol and cloud properties.

Urban Emissions of Water Vapor in Winter.

PubMed

Salmon, Olivia E; Shepson, Paul B; Ren, Xinrong; Marquardt Collow, Allison B; Miller, Mark A; Carlton, Annmarie G; Cambaliza, Maria O L; Heimburger, Alexie; Morgan, Kristan L; Fuentes, Jose D; Stirm, Brian H; Grundman, Robert; Dickerson, Russell R

2017-09-16

Elevated water vapor (H 2 O v ) mole fractions were occassionally observed downwind of Indianapolis, IN, and the Washington, D.C.-Baltimore, MD, area during airborne mass balance experiments conducted during winter months between 2012 and 2015. On days when an urban H 2 O v excess signal was observed, H 2 O v emissions estimates range between 1.6 × 10 4 and 1.7 × 10 5 kg s -1 , and account for up to 8.4% of the total (background + urban excess) advected flow of atmospheric boundary layer H 2 O v from the urban study sites. Estimates of H 2 O v emissions from combustion sources and electricity generation facility cooling towers are 1-2 orders of magnitude smaller than the urban H 2 O v emission rates estimated from observations. Instances of urban H 2 O v enhancement could be a result of differences in snowmelt and evaporation rates within the urban area, due in part to larger wintertime anthropogenic heat flux and land cover differences, relative to surrounding rural areas. More study is needed to understand why the urban H 2 O v excess signal is observed on some days, and not others. Radiative transfer modeling indicates that the observed urban enhancements in H 2 O v and other greenhouse gas mole fractions contribute only 0.1°C day -1 to the urban heat island at the surface. This integrated warming through the boundary layer is offset by longwave cooling by H 2 O v at the top of the boundary layer. While the radiative impacts of urban H 2 O v emissions do not meaningfully influence urban heat island intensity, urban H 2 O v emissions may have the potential to alter downwind aerosol and cloud properties.

Source apportionment vs. emission inventories of non-methane hydrocarbons (NMHC) in an urban area of the Middle East: local and global perspectives

NASA Astrophysics Data System (ADS)

Salameh, T.; Sauvage, S.; Afif, C.; Borbon, A.; Locoge, N.

2015-10-01

We applied the Positive Matrix Factorization model to two large datasets collected during two intensive measurement campaigns (summer 2011 and winter 2012) at a sub-urban site in Beirut, Lebanon, in order to identify NMHC sources and quantify their contribution to ambient levels. Six factors were identified in winter and five factors in summer. PMF-resolved source profiles were consistent with source profiles established by near-field measurements. The major sources were traffic-related emissions (combustion and gasoline evaporation) in winter and in summer accounting for 51 and 74 wt % respectively in agreement with the national emission inventory. The gasoline evaporation related to traffic source had a significant contribution regardless of the season (22 wt % in winter and 30 wt % in summer). The NMHC emissions from road transport are estimated from observations and PMF results, and compared to local and global emission inventories. The national road transport inventory shows lowest emissions than the ones from PMF but with a reasonable difference lower than 50 %. Global inventories show higher discrepancies with lower emissions up to a factor of 10 for the transportation sector. When combining emission inventory to our results, there is a strong evidence that control measures in Lebanon should be targeted on mitigating the NMHC emissions from the traffic-related sources. From a global perspective, an assessment of VOC anthropogenic emission inventories for the Middle East region as a whole seems necessary as these emissions could be much higher than expected at least from the road transport sector. Highlights: - PMF model was applied to identify major NMHC sources and their seasonal variation. - Gasoline evaporation accounts for more than 40 % both in winter and in summer. - NMHC urban emissions are dominated by traffic related sources in both seasons. - Agreement with the emission inventory regarding the relative contribution of the on-road mobile source but disagreement in terms of emission quantities suggesting an underestimation of the inventories.

Impacts of urban forests on offsetting carbon emissions from industrial energy use in Hangzhou, China.

PubMed

Zhao, Min; Kong, Zheng-hong; Escobedo, Francisco J; Gao, Jun

2010-01-01

This study quantified carbon storage and sequestration by urban forests and carbon emissions from energy consumption by several industrial sources in Hangzhou, China. Carbon (C) storage and sequestration were quantified using urban forest inventory data and by applying volume-derived biomass equations and other models relating net primary productivity (NPP) and mean annual biomass increments. Industrial energy use C emissions were estimated by accounting for fossil fuel use and assigning C emission factors. Total C storage by Hangzhou's urban forests was estimated at 11.74 Tg C, and C storage per hectare was 30.25 t C. Carbon sequestration by urban forests was 1,328, 166.55 t C/year, and C sequestration per ha was 1.66 t C/ha/year. Carbon emissions from industrial energy use in Hangzhou were 7 Tg C/year. Urban forests, through sequestration, annually offset 18.57% of the amount of carbon emitted by industrial enterprises, and store an amount of C equivalent to 1.75 times the amount of annual C emitted by industrial energy uses within the city. Management practices for improving Hangzhou's urban forests function of offsetting C emissions from energy consumption are explored. These results can be used to evaluate the urban forests' role in reducing atmospheric carbon dioxide. Copyright 2009 Elsevier Ltd. All rights reserved.

Locational Determinants of Emissions from Pollution-Intensive Firms in Urban Areas

PubMed Central

Zhou, Min; Tan, Shukui; Guo, Mingjing; Zhang, Lu

2015-01-01

Industrial pollution has remained as one of the most daunting challenges for many regions around the world. Characterizing the determinants of industrial pollution should provide important management implications. Unfortunately, due to the absence of high-quality data, rather few studies have systematically examined the locational determinants using a geographical approach. This paper aimed to fill the gap by accessing the pollution source census dataset, which recorded the quantity of discharged wastes (waste water and solid waste) from 717 pollution-intensive firms within Huzhou City, China. Spatial exploratory analysis was applied to analyze the spatial dependency and local clusters of waste emissions. Results demonstrated that waste emissions presented significantly positive autocorrelation in space. The high-high hotspots generally concentrated towards the city boundary, while the low-low clusters approached the Taihu Lake. Their locational determinants were identified by spatial regression. In particular, firms near the city boundary and county road were prone to discharge more wastes. Lower waste emissions were more likely to be observed from firms with high proximity to freight transfer stations or the Taihu Lake. Dense populous districts saw more likelihood of solid waste emissions. Firms in the neighborhood of rivers exhibited higher waste water emissions. Besides, the control variables (firm size, ownership, operation time and industrial type) also exerted significant influence. The present methodology can be applicable to other areas, and further inform the industrial pollution control practices. Our study advanced the knowledge of determinants of emissions from pollution-intensive firms in urban areas. PMID:25927438

[Effects of filamentous macroalgae on the methane emission from urban river: a review].

PubMed

Zhang, Xiu-Yun; Liang, Xia; He, Chi-Quan

2013-05-01

The global warming caused by greenhouse gases emission has raised serious concerns. Recent studies found that the carbon dioxide (CO2) and methane (CH4) emissions from river ecosystem can partly offset the carbon sequestration by terrestrial ecosystem, leading to a rethink of the effects of river ecosystem on the global carbon balance and greenhouse gases emission inventory. As an important primary producer in urban river ecosystem, filamentous macroalgae can deeply affect the carbon cycle process of river system through changing the abiotic and biotic factors in the interface of water-sediment. This paper reviewed the effects of filamentous macroalgae on the CH4 emission from urban river system from the aspects of 1) the effects of urbanization on the river ecosystem and its CH4 emission flux, 2) the effects of filamentous macroalgae on the CH4 generation and emission process in natural river systems, and 3) the effects of filamentous macroalgae on the primary productivity and CH4 emission process in urban river systems. The current problems and future directions in related researches were discussed and prospected.

Characteristics and sources of submicron aerosols above the urban canopy (260 m) in Beijing, China, during the 2014 APEC summit

NASA Astrophysics Data System (ADS)

Chen, C.; Sun, Y. L.; Xu, W. Q.; Du, W.; Zhou, L. B.; Han, T. T.; Wang, Q. Q.; Fu, P. Q.; Wang, Z. F.; Gao, Z. Q.; Zhang, Q.; Worsnop, D. R.

2015-11-01

The megacity of Beijing has experienced frequent severe fine particle pollution during the last decade. Although the sources and formation mechanisms of aerosol particles have been extensively investigated on the basis of ground measurements, real-time characterization of aerosol particle composition and sources above the urban canopy in Beijing is rare. In this study, we conducted real-time measurements of non-refractory submicron aerosol (NR-PM1) composition at 260 m at the Beijing 325 m meteorological tower (BMT) from 10 October to 12 November 2014, by using an aerosol chemical speciation monitor (ACSM) along with synchronous measurements of size-resolved NR-PM1 composition near ground level using a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS). The NR-PM1 composition above the urban canopy was dominated by organics (46 %), followed by nitrate (27 %) and sulfate (13 %). The high contribution of nitrate and high NO3- / SO42- mass ratios illustrates an important role of nitrate in particulate matter (PM) pollution during the study period. The organic aerosol (OA) was mainly composed of secondary OA (SOA), accounting for 61 % on an average. Different from that measured at the ground site, primary OA (POA) correlated moderately with SOA, likely suggesting a high contribution from regional transport above the urban canopy. The Asia-Pacific Economic Cooperation (APEC) summit with strict emission controls provides a unique opportunity to study the impacts of emission controls on aerosol chemistry. All aerosol species were shown to have significant decreases of 40-80 % during APEC from those measured before APEC, suggesting that emission controls over regional scales substantially reduced PM levels. However, the bulk aerosol composition was relatively similar before and during APEC as a result of synergetic controls of aerosol precursors. In addition to emission controls, the routine circulations of mountain-valley breezes were also found to play an important role in alleviating PM levels and achieving the "APEC blue" effect. The evolution of vertical differences between 260 m and the ground level was also investigated. Our results show complex vertical differences during the formation and evolution of severe haze episodes that are closely related to aerosol sources and boundary-layer dynamics.

Characteristics and sources of submicron aerosols above the urban canopy (260 m) in Beijing, China during 2014 APEC summit

NASA Astrophysics Data System (ADS)

Chen, C.; Sun, Y. L.; Xu, W. Q.; Du, W.; Zhou, L. B.; Han, T. T.; Wang, Q. Q.; Fu, P. Q.; Wang, Z. F.; Gao, Z. Q.; Zhang, Q.; Worsnop, D. R.

2015-08-01

The megacity of Beijing has experienced frequent severe fine particle pollution during the last decade. Although the sources and formation mechanisms of aerosol particles have been extensively investigated on the basis of ground measurements, real-time characterization of aerosol particle composition and sources above the urban canopy in Beijing is rare. In this study, we conducted real-time measurements of non-refractory submicron aerosol (NR-PM1) composition at 260 m at the 325 m Beijing Meteorological Tower (BMT) from 10 October to 12 November 2014, by using an aerosol chemical speciation monitor (ACSM) along with synchronous measurements of size-resolved NR-PM1 composition at near ground level using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS). The NR-PM1 composition above the urban canopy was dominated by organics (46 %), followed by nitrate (27 %) and sulfate (13 %). The high contribution of nitrate and high NO3-/SO42- mass ratios illustrate an important role of nitrate in particulate matter (PM) pollution during the study period. The organic aerosol (OA) was mainly composed by secondary OA (SOA), accounting for 61 % on an average. Different from that measured at the ground site, primary OA (POA) correlated moderately with SOA, likely suggesting a high contribution from regional transport above the urban canopy. The Asia-Pacific Economic Cooperation (APEC) summit with strict emission controls provides a unique opportunity to study the impacts of emission controls on aerosol chemistry. All aerosol species were shown to have significant decreases of 40-80 % during APEC from those measured before APEC, suggesting that emission controls over regional scales substantially reduced PM levels. However, the bulk aerosol composition was relatively similar before and during APEC as a result of synergetic controls of aerosol precursors such as SO2, NOx, and volatile organic compounds (VOCs). In addition to emission controls, the routine circulations of mountain-valley breezes were also found to play an important role in alleviating PM levels and achieving the "APEC blue" effect. The evolution of vertical differences between 260 m and the ground level was also investigated. Our results show complex vertical differences during the formation and evolution of severe haze episodes that are closely related to aerosol sources and boundary layer dynamics.

Comparative Analysis of Carbon Dioxide Emissions across Large Urban Areas in the U.S.

NASA Astrophysics Data System (ADS)

Patarasuk, R.; Gurney, K. R.; O'Keeffe, D.; Song, Y.; Rao, P.; Huang, J.; Razlivanov, I. N.

2014-12-01

Carbon dioxide (CO2) emissions from fossil fuel combustion represents the single largest net annual flux of carbon into the atmosphere. Even though urban areas cover only 2% of the earth's surface, they contribute about 70% of global carbon emissions. We aim to conduct a comparative analysis of fossil fuel CO2 (FFCO2) emissions in three large urban areas across different regions in the U.S. based on our spatially-explicit Hestia approach, called the 'Hestia Project'. This research effort is the first to use bottom-up methods to quantify all FFCO2 emissions down to the scale of individual buildings, road segments, and industrial/electricity production facilities on an hourly basis for an entire urban landscape. The Hestia method relies on a large swath of input data such as criteria pollutant emissions reporting, stack monitoring, census data, tax assessor parcel data and traffic monitoring. The urban areas quantified with the Hestia approach include Indianapolis, Salt Lake City, and the Los Angeles Basin (encompassing over 80 cities). A comparative analysis will provide a better understanding of how and why FFCO2 emissions differ across time and space. We examine various factors such as heating/cooling degree days, population, GDP, industrial profile and building age. The study seeks to answer the following questions: 1) How and why do FFCO2 differ across the cities/regions? 2) What drives the different temporal profile of urban emissions? and 3) How do these vary across and within the urban landscape? The results from the study will benefit city planners and other stakeholders in managing urban development and greenhouse gas emissions mitigation.

Wet nitrogen deposition across the urban-intensive agricultural-rural transect of a small urban area in southwest China.

PubMed

Deng, Ouping; Zhang, Shirong; Deng, Liangji; Zhang, Chunlong; Fei, Jianbo

2018-03-01

Understanding of the spatial and temporal variation of the flux of atmospheric nitrogen (N) deposition is essential for assessment of its impact on ecosystems. However, little attention has been paid to the variability of N deposition across urban-intensive agricultural-rural transects. A continuous 2-year observational study (from January 2015 to December 2016) was conducted to determine wet N deposition across the urban-intensive agricultural-rural transect of a small urban area in southwest China. Significantly spatial and temporal variations were found in the research area. Along the urban-intensive agricultural-rural transect, the TN and NH 4 + -N deposition first increased and then decreased, and the NO 3 - -N and dissolved organic N (DON) deposition decreased continuously. Wet N deposition was mainly affected by the districts of agro-facilities, roads and build up lands. Wet NH 4 + -N deposition had non-seasonal emission sources including industrial emissions and urban excretory wastes in urban districts and seasonal emission sources such as fertilizer and manure volatilization in the other districts. However, wet NO 3 - -N deposition had seasonal emission sources such as industrial emissions and fireworks in urban district and non-seasonal emission sources such as transportation in the other districts. Deposition of DON was likely to have had similar sources to NO 3 - -N deposition in rural district, and high-temperature-dependent sources in urban and intensive agricultural districts. Considering the annual wet TN deposition in the intensive agricultural district was about 11.1% of the annual N fertilizer input, N fertilizer rates of crops should be reduced in this region to avoid the excessive application, and the risk of N emissions to the environment.

Do vehicular emissions dominate the source of C6-C8 aromatics in the megacity Shanghai of eastern China?

PubMed

Wang, Hongli; Wang, Qian; Chen, Jianmin; Chen, Changhong; Huang, Cheng; Qiao, Liping; Lou, Shengrong; Lu, Jun

2015-01-01

The characteristic ratios of volatile organic compounds (VOCs) to i-pentane, the indicator of vehicular emissions, were employed to apportion the vehicular and non-vehicular contributions to reactive species in urban Shanghai. Two kinds of tunnel experiments, one tunnel with more than 90% light duty gasoline vehicles and the other with more than 60% light duty diesel vehicles, were carried out to study the characteristic ratios of vehicle-related emissions from December 2009 to January 2010. Based on the experiments, the characteristic ratios of C6-C8 aromatics to i-pentane of vehicular emissions were 0.53 ± 0.08 (benzene), 0.70 ± 0.12 (toluene), 0.41 ± 0.09 (m,p-xylenes), 0.16 ± 0.04 (o-xylene), 0.023 ± 0.011 (styrene), and 0.15 ± 0.02 (ethylbenzene), respectively. The source apportionment results showed that around 23.3% of C6-C8 aromatics in urban Shanghai were from vehicular emissions, which meant that the non-vehicular emissions had more importance. These findings suggested that emission control of non-vehicular sources, i.e. industrial emissions, should also receive attention in addition to the control of vehicle-related emissions in Shanghai. The chemical removal of VOCs during the transport from emissions to the receptor site had a large impact on the apportionment results. Generally, the overestimation of vehicular contributions would occur when the VOC reaction rate constant with OH radicals (kOH) was larger than that of the vehicular indicator, while for species with smaller kOH than the vehicular indicator, the vehicular contribution would be underestimated by the method of characteristic ratios. Copyright © 2014. Published by Elsevier B.V.

The heterogeneous effects of urbanization and income inequality on CO2 emissions in BRICS economies: evidence from panel quantile regression.

PubMed

Zhu, Huiming; Xia, Hang; Guo, Yawei; Peng, Cheng

2018-04-12

This paper empirically examines the effects of urbanization and income inequality on CO 2 emissions in the BRICS economies (i.e., Brazil, Russia, India, China, and South Africa) during the periods 1994-2013. The method we used is the panel quantile regression, which takes into account the unobserved individual heterogeneity and distributional heterogeneity. Our empirical results indicate that urbanization has a significant and negative impact on carbon emissions, except in the 80 th , 90 th , and 95 th quantiles. We also quantitatively investigate the direct and indirect effect of urbanization on carbon emissions, and the results show that we may underestimate urbanization's effect on carbon emissions if we ignore its indirect effect. In addition, in middle- and high-emission countries, income inequality has a significant and positive impact on carbon emissions. The results of our study indicate that in the BRICS economies, there is an inverted U-shaped environmental Kuznets curve (EKC) between the GDP per capita and carbon emissions. The conclusions of this study have important policy implications for policymakers. Policymakers should try to narrow the income gap between the rich and the poor to improve environmental quality; the BRICS economies can speed up urbanization to reduce carbon emissions, but they must improve energy efficiency and use clean energy to the greatest extent in the process.

Characterizing ozone pollution in a petrochemical industrial area in Beijing, China: a case study using a chemical reaction model.

PubMed

Wei, Wei; Lv, Zhaofeng; Cheng, Shuiyuan; Wang, Lili; Ji, Dongsheng; Zhou, Ying; Han, Lihui; Wang, Litao

2015-06-01

This study selected a petrochemical industrial complex in Beijing, China, to understand the characteristics of surface ozone (O3) in this industrial area through the on-site measurement campaign during the July-August of 2010 and 2011, and to reveal the response of local O3 to its precursors' emissions through the NCAR-Master Mechanism model (NCAR-MM) simulation. Measurement results showed that the O3 concentration in this industrial area was significantly higher, with the mean daily average of 124.6 μg/m(3) and mean daily maximum of 236.8 μg/m(3), which are, respectively, 90.9 and 50.6 % higher than those in Beijing urban area. Moreover, the diurnal O3 peak generally started up early in 11:00-12:00 and usually remained for 5-6 h, greatly different with the normal diurnal pattern of urban O3. Then, we used NCAR-MM to simulate the average diurnal variation of photochemical O3 in sunny days of August 2010 in both industrial and urban areas. A good agreement in O3 diurnal variation pattern and in O3 relative level was obtained for both areas. For example of O3 daily maximum, the calculated value in the industrial area was about 51 % higher than in the urban area, while measured value in the industrial area was approximately 60 % higher than in the urban area. Finally, the sensitivity analysis of photochemical O3 to its precursors was conducted based on a set of VOCs/NOx emissions cases. Simulation results implied that in the industrial area, the response of O3 to VOCs was negative and to NOx was positive under the current conditions, with the sensitivity coefficients of -0.16~-0.43 and +0.04~+0.06, respectively. By contrast, the urban area was within the VOCs-limitation regime, where ozone enhancement in response to increasing VOCs emissions and to decreasing NOx emission. So, we think that the VOCs emissions control for this petrochemical industrial complex will increase the potential risk of local ozone pollution aggravation, but will be helpful to inhibit the ozone formation in Beijing urban area through reducing the VOCs transport from the industrial area to the urban area.

Estimation of Anthropogenic Heat Emissions in Delhi, India and Their Role in Urban Heat Island Effect

NASA Astrophysics Data System (ADS)

Bhati, S.; Mohan, M.

2016-12-01

Energy consumption in the urban environment impacts the urban surface energy budget and leads to the emission of anthropogenic sensible heat into the atmosphere. Anthropogenic heat (AH) can vary both in time and space, and are not readily measured. In present study, anthropogenic heat emissions have been estimated using an inventory approach for Delhi. The main sources that have been considered are electricity consumption, vehicular emissions, fuel consumption in domestic sector and waste heat from power plants. Total estimated anthropogenic heat is apportioned gridwise (2 km2) and incorporated in the WRF (version 3.5) model coupled with single-layer Urban canopy model (UCM) to assess the impact of these emissions on urban heat island effect in Delhi. Vehicular emissions have been found to be highest contributor to anthropogenic heat emissions (47%) followed by electricity consumption (28%), domestic fuel consumption (16%) and waste heat from power plants (9%). Highest annual average anthropogenic heat flux was estimated to be 25.2 Wm-2. High flux zones are observed in east Delhi and densely occupied and commercial zones of Sitaram Bazar and Connaught Place. Inclusion of anthropogenic heat emissions in the model improves model performance for near surface temperature as well as urban heat island intensities. Maximum simulated night-time UHI improves from 5.95°C (without AH) to 6.24°C (with AH) against observed value of 6.68°C, thereby indicating positive contribution of anthropogenic heat emissions along with urban canopy towards UHI effect in Delhi. Similarly, spatial distribution and UHI hotspots are found to be comparatively closer to corresponding observed distribution and hotspots with anthropogenic heat emissions being added to the WRF model. Overall, relatively improved model performance is indicative of the impact of anthropogenic heat emissions in local urban meteorology and urban heat island effect in Delhi. Hence, rising population and change in land use-cover and associated anthropogenic activities call for strategic mitigation measures in the city to prevent further strengthening of heat island effect.

Relationship between urbanization and CO2 emissions depends on income level and policy.

PubMed

Ponce de Leon Barido, Diego; Marshall, Julian D

2014-04-01

We investigate empirically how national-level CO2 emissions are affected by urbanization and environmental policy. We use statistical modeling to explore panel data on annual CO2 emissions from 80 countries for the period 1983-2005. Random- and fixed-effects models indicate that, on the global average, the urbanization-emission elasticity value is 0.95 (i.e., a 1% increase in urbanization correlates with a 0.95% increase in emissions). Several regions display a statistically significant, positive elasticity for fixed- and random-effects models: lower-income Europe, India and the Sub-Continent, Latin America, and Africa. Using two proxies for environmental policy/outcomes (ratification status for the Kyoto Protocol; the Yale Environmental Performance Index), we find that in countries with stronger environmental policy/outcomes, urbanization has a more beneficial (or, a less negative) impact on emissions. Specifically, elasticity values are -1.1 (0.21) for higher-income (lower-income) countries with strong environmental policy, versus 0.65 (1.3) for higher-income (lower-income) countries with weak environmental policies. Our finding that the urbanization-emissions elasticity may depend on the strength of a country's environmental policy, not just marginal increases in income, is in contrast to the idea of universal urban scaling laws that can ignore local context. Most global population growth in the coming decades is expected to occur in urban areas of lower-income countries, which underscores the importance of these findings.

The impact of income, trade, urbanization, and financial development on CO2 emissions in 19 emerging economies.

PubMed

Saidi, Kais; Mbarek, Mounir Ben

2017-05-01

This study attempts to empirically examine the impact of financial development, income, trade openness, and urbanization on carbon dioxide emissions for the panel of emerging economies using the time series data over the period 1990-2013. Results showed a positive monotonic relationship between income and CO 2 emissions. All models do not support the EKC hypothesis which assumes an inverted U-shaped relationship between income and environmental degradation. Financial development has a long-run negative impact on carbon emissions, implying that financial development minimizes environmental degradation. This means that financial development can be used as an implement to keep the degradation environmental clean by introducing financial reforms. The urbanization decreases the CO 2 emissions; therefore, it is important for the policymakers and urban planners in these countries to slow the rapid increase in urbanization.

A Review on Mitigation Technologies for Controlling Urban Heat Island Effect in Housing and Settlement Areas

NASA Astrophysics Data System (ADS)

Andoni, Heri; Wonorahardjo, Surjamanto

2018-05-01

Urban Heat Island (UHI) has many harm impacts to urban and human life, the examples are increased building and energy consumption, increased air pollutants emissions, compromised human comfort and health, and many more. Despite UHI phenomenon and those impacts has been realized long enough by the experts along with development of major cities in the world, but its mitigation technology has not been well developed. This paper discusses few mitigation technologies for UHI phenomenon that have been developed by experts. Some mitigation technologies such as double skin façade, shading strategies, and many more are discussed in this study, include the strengths and the weaknesses of each strategy. The focus of the study is mainly on the potential of building skin engineering in which thermal conductivity, infrared emissivity, and specific heat factors. The selected case discussed are buildings made of heavy weight materials. The result in this study reveals a potential map where thermal insulation is one potential strategy to reduce the intensity of UHI through the reduction of heat emissions of heavy building materials components. By this study, improvement of the urban life in its relation to UHI are expected to occur, especially in housing and settlements area.

Factors influencing mobile source particulate matter emissions-to-exposure relationships in the Boston urban area.

PubMed

Greco, Susan L; Wilson, Andrew M; Hanna, Steven R; Levy, Jonathan I

2007-11-15

Benefit-cost and regulatory impact analyses often use atmospheric dispersion models with coarse resolution to estimate the benefits of proposed mobile source emission control regulations. This approach may bias health estimates or miss important intra-urban variability for primary air pollutants. In this study, we estimate primary fine particulate matter (PM2.5) intake fractions (iF; the fraction of a pollutant emitted from a source that is inhaled by the population) for each of 23 398 road segments in the Boston Metro Core area to evaluate the potential for intra-urban variability in the emissions-to-exposure relationship. We estimate iFs using the CAL3QHCR line source model combined with residential populations within 5000 m of each road segment. The annual average values for the road segments range from 0.8 to 53 per million, with a mean of 12 per million. On average, 46% of the total exposure is realized within 200 m of the road segment, though this varies from 0 to 93% largely due to variable population patterns. Our findings indicate the likelihood of substantial intra-urban variability in mobile source primary PM2.5 iF that accounting for population movement with time, localized meteorological conditions, and street-canyon configurations would likely increase.

Estimation of automobile emissions and control strategies in India.

PubMed

Nesamani, K S

2010-03-15

Rapid, but unplanned urban development and the consequent urban sprawl coupled with economic growth have aggravated auto dependency in India over the last two decades. This has resulted in congestion and pollution in cities. The central and state governments have taken many ameliorative measures to reduce vehicular emissions. However, evolution of scientific methods for emission inventory is crucial. Therefore, an attempt has been made to estimate the emissions (running and start) from on-road vehicles in Chennai using IVE model in this paper. GPS was used to collect driving patterns. The estimated emissions from motor vehicles in Chennai in 2005 were 431, 119, 46, 7, 4575, 29, and 0.41 tons/days respectively for CO, VOC, NO(x), PM, CO(2,) CH(4) and N(2)O. It is observed from the results that air quality in Chennai has degraded. The estimation revealed that two and three-wheelers emitted about 64% of the total CO emissions and heavy-duty vehicles accounted for more than 60% and 36% of the NO(x) and PM emissions respectively. About 19% of total emissions were that of start emissions. It is also estimated that on-road transport contributes about 6637 tons/day CO(2) equivalent in Chennai. This paper has further examined various mitigation options to reduce vehicular emissions. The study has concluded that advanced vehicular technology and augmentation of public transit would have significant impact on reducing vehicular emissions.

Inventories and reduction scenarios of urban waste-related greenhouse gas emissions for management potential.

PubMed

Yang, Dewei; Xu, Lingxing; Gao, Xueli; Guo, Qinghai; Huang, Ning

2018-06-01

Waste-related greenhouse gas (GHG) emissions have been recognized as one of the prominent contributors to global warming. Current urban waste regulations, however, face increasing challenges from stakeholders' trade-offs and hierarchic management. A combined method, i.e., life cycle inventories and scenario analysis, was employed to investigate waste-related GHG emissions during 1995-2015 and to project future scenarios of waste-driven carbon emissions by 2050 in a pilot low carbon city, Xiamen, China. The process-based carbon analysis of waste generation (prevention and separation), transportation (collection and transfer) and disposal (treatment and recycling) shows that the main contributors of carbon emissions are associated with waste disposal processes, solid waste, the municipal sector and Xiamen Mainland. Significant spatial differences of waste-related CO 2e emissions were observed between Xiamen Island and Xiamen Mainland using the carbon intensity and density indexes. An uptrend of waste-related CO 2e emissions from 2015 to 2050 is identified in the business as usual, waste disposal optimization, waste reduction and the integrated scenario, with mean annual growth rates of 8.86%, 8.42%, 6.90% and 6.61%, respectively. The scenario and sensitivity analysis imply that effective waste-related carbon reduction requires trade-offs among alternative strategies, actions and stakeholders in a feasible plan, and emphasize a priority of waste prevention and collection in Xiamen. Our results could benefit to the future modeling of urban multiple wastes and life-cycle carbon control in similar cities within and beyond China. Copyright © 2018 Elsevier B.V. All rights reserved.

Cost effective waste management through composting in Africa.

PubMed

Couth, R; Trois, C

2012-12-01

Greenhouse gas (GHG) emissions per person from urban waste management activities are greater in sub-Saharan African countries than in other developing countries, and are increasing as the population becomes more urbanised. Waste from urban areas across Africa is essentially dumped on the ground and there is little control over the resulting gas emissions. The clean development mechanism (CDM), from the 1997 Kyoto Protocol has been the vehicle to initiate projects to control GHG emissions in Africa. However, very few of these projects have been implemented and properly registered. A much more efficient and cost effective way to control GHG emissions from waste is to stabilise the waste via composting and to use the composted material as a soil improver/organic fertiliser or as a component of growing media. Compost can be produced by open windrow or in-vessel composting plants. This paper shows that passively aerated open windrows constitute an appropriate low-cost option for African countries. However, to provide an usable compost material it is recommended that waste is processed through a materials recovery facility (MRF) before being composted. The paper demonstrates that material and biological treatment (MBT) are viable in Africa where they are funded, e.g. CDM. However, they are unlikely to be instigated unless there is a replacement to the Kyoto Protocol, which ceases for Registration in December 2012. Copyright © 2012 Elsevier Ltd. All rights reserved.

Greenhouse gases concentrations and fluxes from subtropical small reservoirs in relation with watershed urbanization

NASA Astrophysics Data System (ADS)

Wang, Xiaofeng; He, Yixin; Yuan, Xingzhong; Chen, Huai; Peng, Changhui; Yue, Junsheng; Zhang, Qiaoyong; Diao, Yuanbin; Liu, Shuangshuang

2017-04-01

Greenhouse gas (GHG) emissions from reservoirs and global urbanization have gained widespread attention, yet the response of GHG emissions to the watershed urbanization is poorly understood. Meanwhile, there are millions of small reservoirs worldwide that receive and accumulate high loads of anthropogenic carbon and nitrogen due to watershed urbanization and can therefore be hotspots of GHG emissions. In this study, we assessed the GHG concentrations and fluxes in sixteen small reservoirs draining urban, agricultural and forested watersheds over a period of one year. The concentrations of pCO2, CH4 and N2O in sampled urban reservoirs that received more sewage input were higher than those in agricultural reservoirs, and were 3, 7 and 10 times higher than those in reservoirs draining in forested areas, respectively. Accordingly, urban reservoirs had the highest estimated GHG flux rate. Regression analysis indicated that dissolved total phosphorus, dissolved organic carbon (DOC) and chlorophyll-a (Chl-a) had great effect on CO2 production, while the nitrogen (N) and phosphorus (P) content of surface water were closely related to CH4 and N2O production. Therefore, these parameters can act as good predictors of GHG emissions in urban watersheds. Given the rapid progress of global urbanization, small urban reservoirs play a crucial role in accounting for regional GHG emissions and cannot be ignored.

Soil greenhouse gas emissions and carbon budgeting in a short-hydroperiod floodplain wetland

USGS Publications Warehouse

Batson, Jackie; Noe, Gregory B.; Hupp, Cliff R.; Krauss, Ken W.; Rybicki, Nancy B.; Schenk, Edward R.

2015-01-01

Understanding the controls on floodplain carbon (C) cycling is important for assessing greenhouse gas emissions and the potential for C sequestration in river-floodplain ecosystems. We hypothesized that greater hydrologic connectivity would increase C inputs to floodplains that would not only stimulate soil C gas emissions but also sequester more C in soils. In an urban Piedmont river (151 km2 watershed) with a floodplain that is dry most of the year, we quantified soil CO2, CH4, and N2O net emissions along gradients of floodplain hydrologic connectivity, identified controls on soil aerobic and anaerobic respiration, and developed a floodplain soil C budget. Sites were chosen along a longitudinal river gradient and across lateral floodplain geomorphic units (levee, backswamp, and toe slope). CO2 emissions decreased downstream in backswamps and toe slopes and were high on the levees. CH4 and N2O fluxes were near zero; however, CH4emissions were highest in the backswamp. Annual CO2 emissions correlated negatively with soil water-filled pore space and positively with variables related to drier, coarser soil. Conversely, annual CH4 emissions had the opposite pattern of CO2. Spatial variation in aerobic and anaerobic respiration was thus controlled by oxygen availability but was not related to C inputs from sedimentation or vegetation. The annual mean soil CO2 emission rate was 1091 g C m−2 yr−1, the net sedimentation rate was 111 g C m−2 yr−1, and the vegetation production rate was 240 g C m−2 yr−1, with a soil C balance (loss) of −338 g C m−2 yr−1. This floodplain is losing C likely due to long-term drying from watershed urbanization.

Variability in carbon dioxide fluxes for dense urban, suburban and woodland environments in southern England

NASA Astrophysics Data System (ADS)

Ward, Helen; Kotthaus, Simone; Grimmond, C. Sue; Bjorkegren, Alex; Wilkinson, Matt; Morrison, Will; Evans, Jon; Morison, James; Christen, Andreas

2014-05-01

The net exchange of carbon dioxide between the surface and atmosphere can be measured using the eddy covariance technique. Fluxes from a dense urban environment (central London), a suburban landscape (Swindon) and a woodland ecosystem (Alice Holt) are compared. All sites are located in southern England and experience similar climatic and meteorological conditions, yet have very different land cover. The signatures of anthropogenic and biogenic processes are explored at various (daily, seasonal and annual) timescales. Particular emphasis is placed on identifying the mixture of controls that determine the flux. In summer, there are clear similarities between the suburban and woodland sites, as the diurnal behaviour is dominated by photosynthetic uptake. In winter, however, vegetation is largely dormant and human activity determines the pattern of fluxes at the urban and suburban sites. Emissions from building heating augment the net release of carbon dioxide in cold months. Road use is a major contributor to the total emissions, and the diurnal cycle in the observed fluxes reflects this: in central London roads are busy throughout the day, whereas in Swindon a double-peaked rush-hour signal is evident. The net exchange of carbon dioxide is estimated for each site and set in context with other studies around the world. Central London has the smallest proportion of vegetation and largest emissions amongst study sites in the literature to date. Although Swindon's appreciable vegetation fraction helps to offset the anthropogenic emissions, even in summertime the 24h total flux is usually positive, indicating carbon release. Comparison of these three sites in a similar region demonstrates the effects of increasing urban density and changing land use on the atmosphere. Findings are relevant in terms of characterising the behaviour of urban surfaces and for quantifying the impact of anthropogenic activities.

Evaluation of bottom-up and downscaled emission inventories for Paris and consequences for estimating urban air pollution increments

NASA Astrophysics Data System (ADS)

Timmermans, R.; Denier van der Gon, H.; Segers, A.; Honore, C.; Perrussel, O.; Builtjes, P.; Schaap, M.

2012-04-01

Since a major part of the Earth's population lives in cities, it is of great importance to correctly characterise the air pollution levels over these urban areas. Many studies in the past have already been dedicated to this subject and have determined so-called urban increments: the impact of large cities on the air pollution levels. The impact of large cities on air pollution levels usually is determined with models driven by so-called downscaled emission inventories. In these inventories official country total emissions are gridded using information on for example population density and location of industries and roads. The question is how accurate are the downscaled inventories over cities or large urban areas. Within the EU FP 7 project MEGAPOLI project a new emission inventory has been produced including refined local emission data for two European megacities (Paris, London) and two urban conglomerations (the Po valley, Italy and the Rhine-Ruhr region, Germany) based on a bottom-up approach. The inventory has comparable national totals but remarkable difference at the city scale. Such a bottom up inventory is thought to be more accurate as it contains local knowledge. Within this study we compared modelled nitrogen dioxide (NO2) and particulate matter (PM) concentrations from the LOTOS-EUROS chemistry transport model driven by a conventional downscaled emission inventory (TNO-MACC inventory) with the concentrations from the same model driven by the new MEGAPOLI 'bottom-up' emission inventory focusing on the Paris region. Model predictions for Paris significantly improve using the new Megapoli inventory. Both the emissions as well as the simulated average concentrations of PM over urban sites in Paris are much lower due to the different spatial distribution of the anthropogenic emissions. The difference for the nearby rural stations is small implicating that also the urban increment for PM simulated using the bottom-up emission inventory is much smaller than for the downscaled emission inventory. Urban increments for PM calculated with downscaled emissions, as is common practice, might therefore be overestimated. This finding is likely to apply to other European Megacities as well.

Connected Vehicle Technologies for Efficient Urban Transportation

DOT National Transportation Integrated Search

2016-10-24

Connected vehicle technology is employed to optimize the vehicle's control system in real-time to reduce congestion, improve fuel economy, and reduce emissions. This project's goal was to develop a two-way communication system to upload vehicle data ...

Bright is the New Black - Multi-Year Performance of Generic High-Albedo Roofs in an Urban Climate

NASA Technical Reports Server (NTRS)

Gaffin, S. R.; Imhoff, M.; Rosenzweig, C.; Khanbilvardi, R.; Pasqualini, A.; Kong, A. Y. Y.; Grillo, D.; Freed, A.; Hillel, D.; Hartung, E.

2012-01-01

High-albedo white and cool roofing membranes are recognized as a fundamental strategy that dense urban areas can deploy on a large scale, at low cost, to mitigate the urban heat island effect. We are monitoring three generic white membranes within New York City that represent a cross-section of the dominant white membrane options for U.S. flat roofs: (1) an ethylene propylene diene monomer (EPDM) rubber membrane; (2) a thermoplastic polyolefin (TPO) membrane and; (3) an asphaltic multi-ply built-up membrane coated with white elastomeric acrylic paint. The paint product is being used by New York City s government for the first major urban albedo enhancement program in its history. We report on the temperature and related albedo performance of these three membranes at three different sites over a multi-year period. The results indicate that the professionally installed white membranes are maintaining their temperature control effectively and are meeting the Energy Star Cool Roofing performance standards requiring a three-year aged albedo above 0.50. The EPDM membrane however shows evidence of low emissivity. The painted asphaltic surface shows high emissivity but lost about half of its initial albedo within two years after installation. Given that the acrylic approach is an important "do-it-yourself," low-cost, retrofit technique, and, as such, offers the most rapid technique for increasing urban albedo, further product performance research is recommended to identify conditions that optimize its long-term albedo control. Even so, its current multi-year performance still represents a significant albedo enhancement for urban heat island mitigation.

A hybrid study of multiple contributors to per capita household CO2 emissions (HCEs) in China.

PubMed

Qu, Jiansheng; Qin, Shanshan; Liu, Lina; Zeng, Jingjing; Bian, Yue

2016-04-01

Given the large expenditures by households on goods and services that contribute a large proportion of global CO2 emissions, increasing attention has been paid to household CO2 emissions (HCEs). However, compared with industrial CO2 emissions, efforts devoted to mitigating HCEs are relatively small. A good understanding of the effects of some driving factors (i.e., urbanization rate, per capita GDP, per capita income/disposable income, Engel coefficient, new energy ratio, carbon intensity, and household size) is urgently needed prior to considering policies for reducing HCEs. Given this, in the study, the direct and indirect per capita HCEs were quantified in rural and urban areas of China over the period 2000-2012. Correlation analysis and gray correlation analysis were initially used to identify the prime drivers of per capita HCEs. Our results showed that per capita income/disposable income, per capita GDP, urbanization rate, and household size were the most significantly correlated with per capita HCEs in rural areas. Moreover, the conjoint effects of the potential driving factors on per capita HCEs were determined by performing principal component regression analysis for all cases. Based on the combined analysis strategies, alternative polices were also examined for controlling and mitigating HCEs growth in China.

Urban Climate, Ozone Formation, and Public Health: Should Heat be Regulated as a Traditional Air Pollutant?

NASA Astrophysics Data System (ADS)

Stone, B.

2003-12-01

The return of record breaking heat waves to North American and European cities in 2003 highlights the growing need for urban planners to develop heat mitigation strategies for large metropolitan regions. Long associated with public health through its effects on human heat stress and heat related mortality, rising urban temperatures also hold important implications for regional air quality. This presentation will outline the results of a study focused on the relationship between regional temperatures and annual tropospheric ozone exceedances in the fifty largest (by population) metropolitan regions in the United States. With the aid of data from the EPA's National Emissions Inventory and NASA's Earth Observing System Data and Information System, this study examines trends in metropolitan emissions of nitrogen oxides, volatile organic compounds, mean regional temperatures, and annual ozone exceedances in U.S. metropolitan regions for the years 1990 through 1999. The intent of this work is to better establish connections between recent trends urban climate and ozone formation and to explore policy approaches to mitigating urban temperatures through physical planning. The results of this research indicate that annual violations of the national ozone standard during the decade of the 1990s were more closely associated with regional temperatures than with the emissions of regulated ozone precursors from mobile and stationary sources. Based on the results of this analysis, I argue that the air quality management strategies outlined in the Clean Air Act may be proving insufficient to control ozone formation due to ongoing and unanticipated changes in global and regional climate. I further argue that the emergence of urban heat as a significant threat to human health demands a strategic response from the fields of urban planning and public health. The presentation will conclude with a discussion of the linkages between urban form and ambient heat and will outline a set of policy approaches that have proven successful in mitigating urban heat production.

Environmental Justice Aspects of Exposure to PM2.5 Emissions from Electric Vehicle Use in China.

PubMed

Ji, Shuguang; Cherry, Christopher R; Zhou, Wenjun; Sawhney, Rapinder; Wu, Ye; Cai, Siyi; Wang, Shuxiao; Marshall, Julian D

2015-12-15

Plug-in electric vehicles (EVs) in China aim to improve sustainability and reduce environmental health impacts of transport emissions. Urban use of EVs rather than conventional vehicles shifts transportation's air pollutant emissions from urban areas (tailpipes) to predominantly rural areas (power plants), changing the geographic distribution of health impacts. We model PM2.5-related health impacts attributable to urban EV use for 34 major cities. Our investigation focuses on environmental justice (EJ) by comparing pollutant inhalation versus income among impacted counties. We find that EVs could increase EJ challenge in China: most (~77%, range: 41-96%) emission inhalation attributable to urban EVs use is distributed to predominately rural communities whose incomes are on average lower than the cities where EVs are used. Results vary dramatically across cities depending on urban income and geography. Discriminant analysis reveals that counties with low income and high inhalation of urban EV emissions have comparatively higher agricultural employment rates, higher mortality rates, more children in the population, and lower education levels. We find that low-emission electricity sources such as renewable energy can help mitigate EJ issues raised here. Findings here are not unique to EVs, but instead are relevant for nearly all electricity-consuming technologies in urban areas.

NOx Emission Reduction and its Effects on Ozone during the 2008 Olympic Games

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yang, Qing; Wang, Yuhang; Zhao, Chun

2011-07-15

We applied a daily-assimilated inversion method to estimate NOx (NO+NO2) emissions for June-September 2007 and 2008 on the basis of the Aura Ozone Monitoring Instrument (OMI) observations of nitrogen dioxide (NO2) and model simulations using the Regional chEmistry and trAnsport Model (REAM). Over urban Beijing, rural Beijing, and the Huabei Plain, OMI column NO2 reductions are approximately 45%, 33%, and 14%, respectively, while the corresponding anthropogenic NOx emission reductions are only 28%, 24%, and 6%, during the full emission control period (July 20 – Sep 20, 2008). The emission reduction began in early July and was in full force bymore » July 20, corresponding to the scheduled implementation of emission controls over Beijing. The emissions did not appear to recover after the emission control period. Meteorological change from summer 2007 to 2008 is the main factor contributing to the column NO2 decreases not accounted for by the emission reduction. Model simulations suggest that the effect of emission reduction on ozone concentrations over Beijing is relatively minor using a standard VOC emission inventory in China. With an adjustment of the model emissions to reflect in situ observations of VOCs in Beijing, the model simulation suggests a larger effect of the emission reduction.« less

Building Low Carbon Cities: Framework to Design and Evaluate Alternative Technologies and Policies for Land Use Planning

NASA Astrophysics Data System (ADS)

Hashimoto, S.; Hamano, H.; Fujita, T.; Hori, H.

2008-12-01

Annex I parties of the Kyoto Protocol are facing even greater pressures to fulfill their commitment for GHG reduction as they enter the first commitment period of the Kyoto Protocol 2008-2012. In Japanese context, one such challenge is to reduce CO2 emissions from the household and business sectors because CO2 emissions from the both sectors has increased by 12% and 20% respectively since 1990 while the industry has achieved 21% of CO2 emissions reduction. Land use planning, which, either directly or indirectly, controls appropriate uses for land within jurisdictions, might play very important roles to deal with CO2 reductions from the household and business sectors. In this research, aiming at effective reductions of air- conditioning energy consumption and resultant CO2 emissions from the household and business sectors, the framework to design and evaluate land use planning was developed. The design and evaluation processes embraced in this framework consist of GIS database, technology and policy inventory for planning, one- dimensional urban canopy model which evaluate urban climate at neighborhood level and air-conditioning load calculation procedure. The GIS database provides spatial information of target areas such as land use, building use and road networks, which, then, helps design alternative land use plans. The technology and policy inventory includes various planning options ranging from those for land over control to those for building energy control, which, combined with the GIS database, serves for planning process. The urban canopy model derives vertical profiles of local climate, such as temperature and humidity, using the information of land use, building height and so on, aided by the GIS database. Vertical profiles of the urban climate are then utilized to derive air-conditioning load and associated CO2 emissions for each building located in target areas. The framework developed was applied to the coastal district of Kawasaki, Japan, with an area of 40 square kilometers, for August 2006, to explore effective combinations of technologies and policies for land use planning. Six alternative land use policies were designed, including BaU in which current land use continues, and were, then, evaluated to seek more effective alternatives. Our findings suggested that about 541 MWh power and 204 tons of CO2 emission be saved at maximum by greening building sites, introducing water retentive pavement and installing energy-saving technologies for buildings in an appropriate manner.

Quantification of fossil fuel CO2 emissions at the urban scale: Results from the Indianapolis Flux Project (INFLUX)

NASA Astrophysics Data System (ADS)

Turnbull, J. C.; Cambaliza, M. L.; Sweeney, C.; Karion, A.; Newberger, T.; Tans, P. P.; Lehman, S.; Davis, K. J.; Miles, N. L.; Richardson, S.; Lauvaux, T.; Shepson, P.; Gurney, K. R.; Song, Y.; Razlivanov, I. N.

2012-12-01

Emissions of fossil fuel CO2 (CO2ff) from anthropogenic sources are the primary driver of observed increases in the atmospheric CO2 burden, and hence global warming. Quantification of the magnitude of fossil fuel CO2 emissions is vital to improving our understanding of the global and regional carbon cycle, and independent evaluation of reported emissions is essential to the success of any emission reduction efforts. The urban scale is of particular interest, because ~75% CO2ff is emitted from urban regions, and cities are leading the way in attempts to reduce emissions. Measurements of 14CO2 can be used to determine CO2ff, yet existing 14C measurement techniques require laborious laboratory analysis and measurements are often insufficient for inferring an urban emission flux. This presentation will focus on how 14CO2 measurements can be combined with those of more easily measured ancillary tracers to obtain high resolution CO2ff mixing ratio estimates and then infer the emission flux. A pilot study over Sacramento, California showed strong correlations between CO2ff and carbon monoxide (CO) and demonstrated an ability to quantify the urban flux, albeit with large uncertainties. The Indianapolis Flux Project (INFLUX) aims to develop and assess methods to quantify urban greenhouse gas emissions. Indianapolis was chosen as an ideal test case because it has relatively straightforward meteorology; a contained, isolated, urban region; and substantial and well-known fossil fuel CO2 emissions. INFLUX incorporates atmospheric measurements of a suite of gases and isotopes including 14C from light aircraft and from a network of existing tall towers surrounding the Indianapolis urban area. The recently added CO2ff content is calculated from measurements of 14C in CO2, and then convolved with atmospheric transport models and ancillary data to estimate the urban CO2ff emission flux. Significant innovations in sample collection include: collection of hourly averaged samples to remove short term atmospheric variability; and direct measurement of the background signal from towers immediately upwind of the urban area and from the boundary layer. We find that CO2ff and other anthropogenic trace gases are consistently enhanced at a tower site downwind of the city. Measurements made directly over or very close to the urban area show only weak correlations between CO2ff and trace gases associated with combustion, likely because the urban plume is not yet well mixed. Total CO2 is also consistently enhanced in the downwind samples, even in summer. In winter, total CO2 enhancement is slightly higher than the fossil fuel CO2 enhancement, in agreement with Indiana's requirement for 10% bioethanol use in gasoline. This result implies that the enhancement in total CO2 can be used to infer CO2ff emissions for Indianapolis during winter. We therefore use the high resolution in situ total CO2 measurements in a simple mass balance model to estimate the urban CO2ff emissions. An initial comparison shows a ~20% difference between the top-down and bottom-up methods.

Comparison of CO2 Emissions Data for 30 Cities from Different Sources

NASA Astrophysics Data System (ADS)

Nakagawa, Y.; Koide, D.; Ito, A.; Saito, M.; Hirata, R.

2017-12-01

Many sources suggest that cities account for a large proportion of global anthropogenic greenhouse gas emissions. Therefore, in search for the best ways to reduce total anthropogenic greenhouse gas emissions, a focus on the city emission is crucial. In this study, we collected CO2 emissions data in 30 cities during 1990-2015 and evaluated the degree of variance between data sources. The CO2 emissions data were obtained from academic papers, municipal reports, and high-resolution emissions maps (CIDIACv2016, EDGARv4.2, ODIACv2016, and FFDASv2.0). To extract urban CO2 emissions from the high-resolution emissions maps, urban fraction ranging from 0 to 1 was calculated for each 1×1 degree grid cell using the global land cover data (SYNMAP). Total CO2 emissions from the grid cells in which urban fraction occupies greater than or equal to 0.9 were regarded as urban CO2 emissions. The estimated CO2 emissions varied greatly depending on the information sources, even in the same year. There was a large difference between CO2 emissions collected from academic papers, municipal reports, and those extracted from high-resolution emissions maps. One reason is that they use different city boundaries. That is, the city proper (i.e. the political city boundary) is often defined as the city boundary in academic papers and municipal reports, whereas the urban area is used in the high-resolution emissions maps. Furthermore, there was a large variation in CO2 emissions collected from academic papers and municipal reports. These differences may be due to the difference in the assumptions such as allocation ratio of CO2 emissions to producers and consumers. In general, the consumption-based assignment of emissions gives higher estimates of urban CO2 emission in comparison with production-based assignment. Furthermore, there was also a large variation in CO2 emissions extracted from high-resolution emissions maps. This difference would be attributable to differences in information used in the spatial disaggregation of emissions. To identify the CO2 emissions from cities, it is necessary to determine common definitions of city boundaries, allocation ratio of CO2 emissions to consumption and production, and refined approach of the spatial disaggregation of CO2 emissions in high-resolution emissions maps.

Analyzing the efficacy of subtropical urban forests in offsetting carbon emissions from cities

Treesearch

Francisco Escobedo; Sebastian Varela; Min Zhao; John E. Wagner; Wayne Zipperer

2010-01-01

Urban forest management and policies have been promoted as a tool to mitigate carbon dioxide (CO2) emissions. This study used existing CO2 reduction measures from subtropical Miami-Dade and Gainesville, USA and modeled carbon storage and sequestration by trees to analyze policies that use urban forests to offset carbon emissions. Field data were analyzed, modeled, and...

Controlling air pollution from passenger ferries: cost-effectiveness of seven technological options.

PubMed

Farrell, Alexander E; Corbett, James J; Winebrake, James J

2002-12-01

Continued interest in improving air quality in the United States along with renewed interest in the expansion of urban passenger ferry service has created concern about air pollution from ferry vessels. This paper presents a methodology for estimating the air pollution emissions from passenger ferries and the costs of emissions control strategies. The methodology is used to estimate the emissions and costs of retrofitting or re-powering ferries with seven technological options (combinations of propulsion and emission control systems) onto three vessels currently in service in San Francisco Bay. The technologies include improved engine design, cleaner fuels (including natural gas), and exhaust gas cleanup devices. The three vessels span a range of ages and technologies, from a 25-year-old monohull to a modern, high-speed catamaran built only four years ago. By looking at a range of technologies, vessel designs, and service conditions, a sense of the broader implications of controlling emissions from passenger ferries across a range of vessels and service profiles is provided. Tier 2-certified engines are the most cost-effective choice, but all options are cost-effective relative to other emission control strategies already in place in the transportation system.

Air-quality in the mid-21st century for the city of Paris under two climate scenarios; from regional to local scale

NASA Astrophysics Data System (ADS)

Markakis, K.; Valari, M.; Colette, A.; Sanchez, O.; Perrussel, O.; Honore, C.; Vautard, R.; Klimont, Z.; Rao, S.

2014-01-01

Ozone and PM2.5 concentrations over the city of Paris are modeled with the CHIMERE air-quality model at 4 km × 4 km horizontal resolution for two future emission scenarios. High-resolution (1 km × 1 km) emission projection until 2020 for the greater Paris region is developed by local experts (AIRPARIF) and is further extended to year 2050 based on regional scale emission projections developed by the Global Energy Assessment. Model evaluation is performed based on a 10 yr control simulation. Ozone is in very good agreement with measurements while PM2.5 is underestimated by 20% over the urban area mainly due to a large wet bias in wintertime precipitation. A significant increase of maximum ozone relative to present time levels over Paris is modeled under the "business as usual" scenario (+7 ppb) while a more optimistic mitigation scenario leads to moderate ozone decrease (-3.5 ppb) in year 2050. These results are substantially different to previous regional scale projections where 2050 ozone is found to decrease under both future scenarios. A sensitivity analysis showed that this difference is due to the fact that ozone formation over Paris at the current, urban scale study, is driven by VOC-limited chemistry, whereas at the regional scale ozone formation occurs under NOx-sensitive conditions. This explains why the sharp NOx reductions implemented in the future scenarios have a different effect on ozone projections at different scales. In rural areas projections at both scales yield similar results showing that the longer time-scale processes of emission transport and ozone formation are less sensitive to model resolution. PM2.5 concentrations decrease by 78% and 89% under "business as usual" and "mitigation" scenarios respectively compared to present time period. The reduction is much more prominent over the urban part of the domain due to the effective reductions of road transport and residential emissions resulting in the smoothing of the large urban increment modelled in the control simulation.

Air quality in the mid-21st century for the city of Paris under two climate scenarios; from the regional to local scale

NASA Astrophysics Data System (ADS)

Markakis, K.; Valari, M.; Colette, A.; Sanchez, O.; Perrussel, O.; Honore, C.; Vautard, R.; Klimont, Z.; Rao, S.

2014-07-01

Ozone and PM2.5 concentrations over the city of Paris are modeled with the CHIMERE air-quality model at 4 km × 4 km horizontal resolution for two future emission scenarios. A high-resolution (1 km × 1 km) emission projection until 2020 for the greater Paris region is developed by local experts (AIRPARIF) and is further extended to year 2050 based on regional-scale emission projections developed by the Global Energy Assessment. Model evaluation is performed based on a 10-year control simulation. Ozone is in very good agreement with measurements while PM2.5 is underestimated by 20% over the urban area mainly due to a large wet bias in wintertime precipitation. A significant increase of maximum ozone relative to present-day levels over Paris is modeled under the "business-as-usual" scenario (+7 ppb) while a more optimistic "mitigation" scenario leads to a moderate ozone decrease (-3.5 ppb) in year 2050. These results are substantially different to previous regional-scale projections where 2050 ozone is found to decrease under both future scenarios. A sensitivity analysis showed that this difference is due to the fact that ozone formation over Paris at the current urban-scale study is driven by volatile organic compound (VOC)-limited chemistry, whereas at the regional-scale ozone formation occurs under NOx-sensitive conditions. This explains why the sharp NOx reductions implemented in the future scenarios have a different effect on ozone projections at different scales. In rural areas, projections at both scales yield similar results showing that the longer timescale processes of emission transport and ozone formation are less sensitive to model resolution. PM2.5 concentrations decrease by 78% and 89% under business-as-usual and mitigation scenarios, respectively, compared to the present-day period. The reduction is much more prominent over the urban part of the domain due to the effective reductions of road transport and residential emissions resulting in the smoothing of the large urban increment modeled in the control simulation.

Quantifying Diurnal and Seasonal Variation in On-road CO2 Emissions Across the Northeastern U.S.

NASA Astrophysics Data System (ADS)

Gately, C.; Hutyra, L.

2014-12-01

On-road emissions comprised 29% of U.S. fossil fuel carbon dioxide emissions in 2012, with 64% of those emissions occurring in urban areas. Understanding the social, economic and technological factors that influence urban emissions requires the development of emissions inventories that are resolved at fine spatial and temporal scales. As city governments are increasingly at the forefront of developing policies to mitigate greenhouse gas emissions from vehicles, high-resolution, bottom-up inventories will support local and regional emissions benchmarking, as well as the monitoring, reporting, and verification of trends in emissions across time and space. To that end, we combine a large regional dataset of hourly traffic counts with the 1km gridded estimates of on-road CO2 emissions from the Database of Road Transportation Emissions (DARTE) to develop hourly CO2 emissions estimates for the year 2012 that cover 12 northeastern states. The inventory scope covers several large metropolitan regions as well as many small- and medium-sized urban, suburban and exurban population centers, altogether representing 20% of urban and 17% of total U.S. on-road CO2 emissions in 2012. We identify significant variation in the time structure of vehicle emissions across the urban-suburban gradients of the Boston, New York, and Washington, D.C. metropolitan areas. In particular we note considerable spatial variation between morning and evening peak periods, both within and between cities, as well as variations in the duration of peak periods, depending on time of year and spatial location. We also examine the relationship between the temporal and spatial structure of morning and evening peak period emissions and the spatial distribution of population and employment density across urban to rural gradients. Finally we utilize data on minute-by-minute vehicle speeds to quantify the effect of traffic congestion on vehicle CO2 emission rates across the Boston metro area, and we highlight the sensitivity of congestion to small sub-hourly variations in traffic flows at key periods of the morning and evening rush hours. Results from our analysis demonstrate the potential for reducing vehicle emissions through time-sensitive toll pricing or commuter incentive schemes targeting peak period vehicle use on urban freeways.

Replacing Gasoline : Alternative Fuels for Light-Duty Vehicles

DOT National Transportation Integrated Search

1990-09-01

Among the several major issues that Congress addressed in the process of reauthorizing the Clean Air Act was the future role of alternative highway transportation fuels in reducing urban smog. As vehicular emissions control efficiencies rose past 90 ...

Secondary organic aerosol production from diesel vehicle exhaust: impact of aftertreatment, fuel chemistry and driving cycle

NASA Astrophysics Data System (ADS)

Gordon, T. D.; Presto, A. A.; Nguyen, N. T.; Robertson, W. H.; Na, K.; Sahay, K. N.; Zhang, M.; Maddox, C.; Rieger, P.; Chattopadhyay, S.; Maldonado, H.; Maricq, M. M.; Robinson, A. L.

2014-05-01

Environmental chamber ("smog chamber") experiments were conducted to investigate secondary organic aerosol (SOA) production from dilute emissions from two medium-duty diesel vehicles (MDDVs) and three heavy-duty diesel vehicles (HDDVs) under urban-like conditions. Some of the vehicles were equipped with emission control aftertreatment devices, including diesel particulate filters (DPFs), selective catalytic reduction (SCR) and diesel oxidation catalysts (DOCs). Experiments were also performed with different fuels (100% biodiesel and low-, medium- or high-aromatic ultralow sulfur diesel) and driving cycles (Unified Cycle,~Urban Dynamometer Driving Schedule, and creep + idle). During normal operation, vehicles with a catalyzed DPF emitted very little primary particulate matter (PM). Furthermore, photooxidation of dilute emissions from these vehicles produced essentially no SOA (below detection limit). However, significant primary PM emissions and SOA production were measured during active DPF regeneration experiments. Nevertheless, under reasonable assumptions about DPF regeneration frequency, the contribution of regeneration emissions to the total vehicle emissions is negligible, reducing PM trapping efficiency by less than 2%. Therefore, catalyzed DPFs appear to be very effective in reducing both primary PM emissions and SOA production from diesel vehicles. For both MDDVs and HDDVs without aftertreatment substantial SOA formed in the smog chamber - with the emissions from some vehicles generating twice as much SOA as primary organic aerosol after 3 h of oxidation at typical urban VOC / NOx ratios (3 : 1). Comprehensive organic gas speciation was performed on these emissions, but less than half of the measured SOA could be explained by traditional (speciated) SOA precursors. The remainder presumably originates from the large fraction (~30%) of the nonmethane organic gas emissions that could not be speciated using traditional one-dimensional gas chromatography. The unspeciated organics - likely comprising less volatile species such as intermediate volatility organic compounds - appear to be important SOA precursors; we estimate that the effective SOA yield (defined as the ratio of SOA mass to reacted precursor mass) was 9 ± 6% if both speciated SOA precursors and unspeciated organics are included in the analysis. SOA production from creep + idle operation was 3-4 times larger than SOA production from the same vehicle operated over the Urban Dynamometer Driving Schedule (UDDS). Fuel properties had little or no effect on primary PM emissions or SOA formation.

The Urban Forest Effects (UFORE) model: quantifying urban forest structure and functions

Treesearch

David J. Nowak; Daniel E. Crane

2000-01-01

The Urban Forest Effects (UFORE) computer model was developed to help managers and researchers quantify urban forest structure and functions. The model quantifies species composition and diversity, diameter distribution, tree density and health, leaf area, leaf biomass, and other structural characteristics; hourly volatile organic compound emissions (emissions that...

Dynamic analysis of the urban-based low-carbon policy using system dynamics: Focused on housing and green space

NASA Astrophysics Data System (ADS)

Hong, Taehoon; Kim, Jimin; Koo, Choongwan; Jeong, Kwangbok

2015-02-01

To systematically manage the energy consumption of existing buildings, the government has to enforce greenhouse gas reduction policies. However, most of the policies are not properly executed because they do not consider various factors from the urban level perspective. Therefore, this study aimed to conduct a dynamic analysis of an urban-based low-carbon policy using system dynamics, with a specific focus on housing and green space. This study was conducted in the following steps: (i) establishing the variables of urban-based greenhouse gases (GHGs) emissions; (ii) creating a stock/flow diagram of urban-based GHGs emissions; (iii) conducting an information analysis using the system dynamics; and (iv) proposing the urban-based low-carbon policy. If a combined energy policy that uses the housing sector (30%) and the green space sector (30%) at the same time is implemented, 2020 CO2 emissions will be 7.23 million tons (i.e., 30.48% below 2020 business-as-usual), achieving the national carbon emissions reduction target (26.9%). The results of this study could contribute to managing and improving the fundamentals of the urban-based low-carbon policies to reduce greenhouse gas emissions.

Fine particulate matter emissions inventories: comparisons of emissions estimates with observations from recent field programs.

PubMed

Simon, Heather; Allen, David T; Wittig, Ann E

2008-02-01

Emissions inventories of fine particulate matter (PM2.5) were compared with estimates of emissions based on data emerging from U.S. Environment Protection Agency Particulate Matter Supersites and other field programs. Six source categories for PM2.5 emissions were reviewed: on-road mobile sources, nonroad mobile sources, cooking, biomass combustion, fugitive dust, and stationary sources. Ammonia emissions from all of the source categories were also examined. Regional emissions inventories of PM in the exhaust from on-road and nonroad sources were generally consistent with ambient observations, though uncertainties in some emission factors were twice as large as the emission factors. In contrast, emissions inventories of road dust were up to an order of magnitude larger than ambient observations, and estimated brake wear and tire dust emissions were half as large as ambient observations in urban areas. Although comprehensive nationwide emissions inventories of PM2.5 from cooking sources and biomass burning are not yet available, observational data in urban areas suggest that cooking sources account for approximately 5-20% of total primary emissions (excluding dust), and biomass burning sources are highly dependent on region. Finally, relatively few observational data were available to assess the accuracy of emission estimates for stationary sources. Overall, the uncertainties in primary emissions for PM2.s are substantial. Similar uncertainties exist for ammonia emissions. Because of these uncertainties, the design of PM2.5 control strategies should be based on inventories that have been refined by a combination of bottom-up and top-down methods.

Greenhouse gas emissions accounting of urban residential consumption: a household survey based approach.

PubMed

Lin, Tao; Yu, Yunjun; Bai, Xuemei; Feng, Ling; Wang, Jin

2013-01-01

Devising policies for a low carbon city requires a careful understanding of the characteristics of urban residential lifestyle and consumption. The production-based accounting approach based on top-down statistical data has a limited ability to reflect the total greenhouse gas (GHG) emissions from residential consumption. In this paper, we present a survey-based GHG emissions accounting methodology for urban residential consumption, and apply it in Xiamen City, a rapidly urbanizing coastal city in southeast China. Based on this, the main influencing factors determining residential GHG emissions at the household and community scale are identified, and the typical profiles of low, medium and high GHG emission households and communities are identified. Up to 70% of household GHG emissions are from regional and national activities that support household consumption including the supply of energy and building materials, while 17% are from urban level basic services and supplies such as sewage treatment and solid waste management, and only 13% are direct emissions from household consumption. Housing area and household size are the two main factors determining GHG emissions from residential consumption at the household scale, while average housing area and building height were the main factors at the community scale. Our results show a large disparity in GHG emissions profiles among different households, with high GHG emissions households emitting about five times more than low GHG emissions households. Emissions from high GHG emissions communities are about twice as high as from low GHG emissions communities. Our findings can contribute to better tailored and targeted policies aimed at reducing household GHG emissions, and developing low GHG emissions residential communities in China.

Greenhouse Gas Emissions Accounting of Urban Residential Consumption: A Household Survey Based Approach

PubMed Central

Lin, Tao; Yu, Yunjun; Bai, Xuemei; Feng, Ling; Wang, Jin

2013-01-01

Devising policies for a low carbon city requires a careful understanding of the characteristics of urban residential lifestyle and consumption. The production-based accounting approach based on top-down statistical data has a limited ability to reflect the total greenhouse gas (GHG) emissions from residential consumption. In this paper, we present a survey-based GHG emissions accounting methodology for urban residential consumption, and apply it in Xiamen City, a rapidly urbanizing coastal city in southeast China. Based on this, the main influencing factors determining residential GHG emissions at the household and community scale are identified, and the typical profiles of low, medium and high GHG emission households and communities are identified. Up to 70% of household GHG emissions are from regional and national activities that support household consumption including the supply of energy and building materials, while 17% are from urban level basic services and supplies such as sewage treatment and solid waste management, and only 13% are direct emissions from household consumption. Housing area and household size are the two main factors determining GHG emissions from residential consumption at the household scale, while average housing area and building height were the main factors at the community scale. Our results show a large disparity in GHG emissions profiles among different households, with high GHG emissions households emitting about five times more than low GHG emissions households. Emissions from high GHG emissions communities are about twice as high as from low GHG emissions communities. Our findings can contribute to better tailored and targeted policies aimed at reducing household GHG emissions, and developing low GHG emissions residential communities in China. PMID:23405187

Carbon and nitrogen isotopes unravels sources of aerosol contamination at Caribbean rural and urban coastal sites.

PubMed

Morera-Gómez, Yasser; Santamaría, Jesús Miguel; Elustondo, David; Alonso-Hernández, Carlos Manuel; Widory, David

2018-06-15

The constant increase of anthropogenic emissions of aerosols, usually resulting from a complex mixture from various sources, leads to a deterioration of the ambient air quality. The stable isotope compositions (δ 13 C and δ 15 N) of total carbon (TC) and nitrogen (TN) in both PM 10 and emissions from potential sources were investigated for first time in a rural and an urban Caribbean costal sites in Cuba to better constrain the origin of the contamination. Emissions from road traffic, power plant and shipping emissions were discriminated by coupling their C and N contents and corresponding isotope signatures. Other sources (soil, road dust and cement plant), in contrast, presented large overlapping ranges for both C and N isotope compositions. δ 13 C PM10 isotope compositions in the rural (average of -25.4 ± 1.2‰) and urban (average of -24.8 ± 1.2‰) sites were interpreted as a mixture of contributions from two main contributors: i) fossil fuel combustion and ii) cement plant and quarries. Results also showed that this last source is impacting more air quality at the urban site. A strong influence from local wood burning was also identified at the rural site. These conclusions were comforted by a statistical analysis using a conditional bivariate probability function. TN and δ 15 N values from the urban site demonstrated that nitrogen in PM 10 was generated by secondary processes through the formation of (NH 4 ) 2 SO 4 . The exchange in the (NH 4 ) 2 SO 4 molecule between gaseous NH 3 and particle NH 4 + under stoichiometric equilibrium may control the observed 15 N enrichment. At low nitrogen concentrations in the aerosols, representing PM 10 with both the highest primary N and lowest secondary N proportions, comparison with the δ 15 N of potential sources indicate that emissions from diesel car and power plant emissions may represent the major vectors of primary nitrogen. Copyright © 2018 Elsevier B.V. All rights reserved.

Urbanization in China changes the composition and main sources of wet inorganic nitrogen deposition.

PubMed

Huang, Juan; Zhang, Wei; Zhu, Xiaomin; Gilliam, Frank S; Chen, Hao; Lu, Xiankai; Mo, Jiangming

2015-05-01

Nowadays, nitrogen (N) deposition has become a growing global concern due to urbanization activities increasing the large amount of reactive N in the atmosphere. However, it remains unclear whether urbanization affects the composition and main sources of N deposition in rapidly urbanizing areas such as in China. One-year measurement of wet inorganic N deposition was conducted using ion-exchange resin (IER) columns in the range of 260 km from urban to rural areas in the Pearl River Delta (PRD) region, south China. An increasing pattern of wet inorganic deposition along the urbanization gradient was observed and it increased in the order: rural (15.26 ± 0.20 kg N ha(-1) year(-1)) < suburban/rural (21.45 ± 3.73 kg N ha(-1) year(-1)) < urban (31.16 ± 0.44 kg N ha(-1) year(-1)) < urban/suburban sites (34.15 ± 5.73 kg N ha(-1) year(-1)). Nitrate N (NO3 (-)-N) accounted for 53.5-79.1 % of total wet inorganic N deposition, indicating a significant negative correlation with distance from the urban core. Based on moss δ(15)N-values the main source of NO3 (-)-N was considered to be emitted from vehicles. Our results demonstrate that urbanization has large impacts on the regional pattern of wet inorganic N deposition. Thus, controlling NOx emission, especially vehicle emission will become an effective strategy for N pollution abatement in China.

Carbon dioxide emissions and change in prevalence of obesity and diabetes in the United States: an ecological study.

PubMed

Zheutlin, Alexander R; Adar, Sara D; Park, Sung Kyun

2014-12-01

Recent studies suggest that increasing levels of the greenhouse gas, carbon dioxide (CO2), may influence weight gain and thus may play a role in rising trends in obesity and diabetes. We conducted an ecological study to examine the associations between CO2 emissions from fossil fuel combustion and changes in the prevalence of obesity and diabetes in the United States. County-level data on CO2 emissions, prevalence of obesity and diagnosed diabetes, other sociodemographic factors and neighborhood characteristics related to urbanicity, and fine particles (PM2.5) between 2004 and 2008 were obtained from the Vulcan Project, Centers for Disease Control and Prevention, and American Community Survey. Linear mixed effect modeling of 3019 counties for the associations between average CO2 emissions and changes in diabetes and obesity prevalence between 2004 and 2008 was performed. The average obesity and diabetes prevalence increased between 2004 and 2008 by 3.65% (SD: 1.88%) and 1.65% (SD: 1.70%), respectively. A marginally significant positive association between CO2 emission and changes in obesity prevalence was found with adjustment for sociodemographic factors, indicators of urbanicity and spatial autocorrelation (p-trend=0.06). The association became weaker and nonsignificant with further adjustment for PM2.5 (p-trend=0.17). There was a significant positive association between CO2 emission and changes in diabetes prevalence before controlling for PM2.5 (p-trend=0.05) but the association became null after controlling for PM2.5 (p-trend=0.49), suggesting that PM2.5 is a critical confounder in the association between CO2 emission and changes in diabetes prevalence. This study does not support the hypothesis that CO2 emissions, a leading driver of climate change, may be linked to increasing trends in obesity and diabetes, though there was an indication of possible link between CO2 and obesity. Copyright © 2014 Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hong, Taehoon, E-mail: hong7@yonsei.ac.kr; Kim, Jimin, E-mail: cookie6249@yonsei.ac.kr; Jeong, Kwangbok, E-mail: kbjeong7@yonsei.ac.kr

To systematically manage the energy consumption of existing buildings, the government has to enforce greenhouse gas reduction policies. However, most of the policies are not properly executed because they do not consider various factors from the urban level perspective. Therefore, this study aimed to conduct a dynamic analysis of an urban-based low-carbon policy using system dynamics, with a specific focus on housing and green space. This study was conducted in the following steps: (i) establishing the variables of urban-based greenhouse gases (GHGs) emissions; (ii) creating a stock/flow diagram of urban-based GHGs emissions; (iii) conducting an information analysis using the systemmore » dynamics; and (iv) proposing the urban-based low-carbon policy. If a combined energy policy that uses the housing sector (30%) and the green space sector (30%) at the same time is implemented, 2020 CO{sub 2} emissions will be 7.23 million tons (i.e., 30.48% below 2020 business-as-usual), achieving the national carbon emissions reduction target (26.9%). The results of this study could contribute to managing and improving the fundamentals of the urban-based low-carbon policies to reduce greenhouse gas emissions.« less

Development of a comprehensive air quality modeling framework for a coastal urban airshed in south Texas

NASA Astrophysics Data System (ADS)

Farooqui, Mohmmed Zuber

Tropospheric ozone is one of the major air pollution problems affecting urban areas of United States as well as other countries in the world. Analysis of surface observed ozone levels in south and central Texas revealed several days exceeding 8-hour average ozone National Ambient of Air Quality Standards (NAAQS) over the past decade. Two major high ozone episodes were identified during September of 1999 and 2002. A photochemical modeling framework for the high ozone episodes in 1999 and 2002 were developed for the Corpus Christi urban airshed. The photochemical model was evaluated as per U.S. Environmental Protection Agency (EPA) recommended statistical methods and the models performed within the limits set by EPA. An emission impact assessment of various sources within the urban airshed was conducted using the modeling framework. It was noted that by nudging MM5 with surface observed meteorological parameters and sea-surface temperature, the coastal meteorological predictions improved. Consequently, refined meteorology helped the photochemical model to better predict peak ozone levels in urban airsheds along the coastal margins of Texas including in Corpus Christi. The emissions assessment analysis revealed that Austin and San Antonio areas were significantly affected by on-road mobile emissions from light-duty gasoline and heavy-duty diesel vehicles. The urban areas of San Antonio, Austin, and Victoria areas were estimated to be NOx sensitive. Victoria was heavily influenced by point sources in the region while Corpus Christi was influenced by both point and non-road mobile sources and was identified to be sensitive to VOC emissions. A rise in atmospheric temperature due to climate change potentially increase ozone exceedances and the peak ozone levels within the study region and this will be a major concern for air quality planners. This study noted that any future increase in ambient temperature would result in a significant increase in the urban and regional ozone levels within the modeling domain and it would also enhance the transported levels of ozone across the region. Overall, the photochemical modeling framework helped in evaluating the impact of various parameters affecting ozone air quality; and, it has the potential to be a tool for policy-makers to develop effective emissions control strategies under various regulatory and climate conditions.

Top-down quantification of NOx emissions from traffic in an urban area using a high-resolution regional atmospheric chemistry model

NASA Astrophysics Data System (ADS)

Kuik, Friderike; Kerschbaumer, Andreas; Lauer, Axel; Lupascu, Aurelia; von Schneidemesser, Erika; Butler, Tim M.

2018-06-01

With NO2 limit values being frequently exceeded in European cities, complying with the European air quality regulations still poses a problem for many cities. Traffic is typically a major source of NOx emissions in urban areas. High-resolution chemistry transport modelling can help to assess the impact of high urban NOx emissions on air quality inside and outside of urban areas. However, many modelling studies report an underestimation of modelled NOx and NO2 compared with observations. Part of this model bias has been attributed to an underestimation of NOx emissions, particularly in urban areas. This is consistent with recent measurement studies quantifying underestimations of urban NOx emissions by current emission inventories, identifying the largest discrepancies when the contribution of traffic NOx emissions is high. This study applies a high-resolution chemistry transport model in combination with ambient measurements in order to assess the potential underestimation of traffic NOx emissions in a frequently used emission inventory. The emission inventory is based on officially reported values and the Berlin-Brandenburg area in Germany is used as a case study. The WRF-Chem model is used at a 3 km × 3 km horizontal resolution, simulating the whole year of 2014. The emission data are downscaled from an original resolution of ca. 7 km × 7 km to a resolution of 1 km × 1 km. An in-depth model evaluation including spectral decomposition of observed and modelled time series and error apportionment suggests that an underestimation in traffic emissions is likely one of the main causes of the bias in modelled NO2 concentrations in the urban background, where NO2 concentrations are underestimated by ca. 8 µg m-3 (-30 %) on average over the whole year. Furthermore, a diurnal cycle of the bias in modelled NO2 suggests that a more realistic treatment of the diurnal cycle of traffic emissions might be needed. Model problems in simulating the correct mixing in the urban planetary boundary layer probably play an important role in contributing to the model bias, particularly in summer. Also taking into account this and other possible sources of model bias, a correction factor for traffic NOx emissions of ca. 3 is estimated for weekday daytime traffic emissions in the core urban area, which corresponds to an overall underestimation of traffic NOx emissions in the core urban area of ca. 50 %. Sensitivity simulations for the months of January and July using the calculated correction factor show that the weekday model bias can be improved from -8.8 µg m-3 (-26 %) to -5.4 µg m-3 (-16 %) in January on average in the urban background, and -10.3 µg m-3 (-46 %) to -7.6 µg m-3 (-34 %) in July. In addition, the negative bias of weekday NO2 concentrations downwind of the city in the rural and suburban background can be reduced from -3.4 µg m-3 (-12 %) to -1.2 µg m-3 (-4 %) in January and from -3.0 µg m-3 (-22 %) to -1.9 µg m-3 (-14 %) in July. The results and their consistency with findings from other studies suggest that more research is needed in order to more accurately understand the spatial and temporal variability in real-world NOx emissions from traffic, and apply this understanding to the inventories used in high-resolution chemical transport models.

Investigation of CO2 emission reduction strategy from in-use gasoline vehicle

NASA Astrophysics Data System (ADS)

Choudhary, Arti; Gokhale, Sharad

2016-04-01

On road transport emissions is kicking off in Indian cities due to high levels of urbanization and economic growth during the last decade in Indian subcontinent. In 1951, about 17% of India's population were living in urban areas that increased to 32% in 2011. Currently, India is fourth largest Green House Gas (GHG) emitter in the world, with its transport sector being the second largest contributor of CO2 emissions. For achieving prospective carbon reduction targets, substantial opportunity among in-use vehicle is necessary to quantify. Since, urban traffic flow and operating condition has significant impact on exhaust emission (Choudhary and Gokhale, 2016). This study examined the influence of vehicular operating kinetics on CO2 emission from predominant private transportation vehicles of Indian metropolitan city, Guwahati. On-board instantaneous data were used to quantify the impact of CO2 emission on different mileage passenger cars and auto-rickshaws at different times of the day. Further study investigates CO2 emission reduction strategies by using International Vehicle Emission (IVE) model to improve co-benefit in private transportation by integrated effort such as gradual phase-out of inefficient vehicle and low carbon fuel. The analysis suggests that fuel type, vehicles maintenance and traffic flow management have potential for reduction of urban sector GHG emissions. Keywords: private transportation, CO2, instantaneous emission, IVE model Reference Choudhary, A., Gokhale, S. (2016). Urban real-world driving traffic emissions during interruption and congestion. Transportation Research Part D: Transport and Environment 43: 59-70.

Situated lifestyles: I. How lifestyles change along with the level of urbanization and what the greenhouse gas implications are—a study of Finland

NASA Astrophysics Data System (ADS)

Heinonen, Jukka; Jalas, Mikko; Juntunen, Jouni K.; Ala-Mantila, Sanna; Junnila, Seppo

2013-06-01

An extensive body of literature demonstrates how higher density leads to more efficient energy use and lower greenhouse gas (GHG) emissions from transport and housing. However, our current understanding seems to be limited on the relationships between the urban form and the GHG emissions, namely how the urban form affects the lifestyles and thus the GHGs on a much wider scale than traditionally assumed. The urban form affects housing types, commuting distances, availability of different goods and services, social contacts and emulation, and the alternatives for pastimes, meaning that lifestyles are actually situated instead of personal projects. As almost all consumption, be it services or products, involves GHG emissions, looking at the emissions from transport and housing may not be sufficient to define whether one form would be more desirable than another. In the paper we analyze the urban form-lifestyle relationships in Finland together with the resulting GHG implications, employing both monetary expenditure and time use data to portray lifestyles in different basic urban forms: metropolitan, urban, semi-urban and rural. The GHG implications are assessed with a life cycle assessment (LCA) method that takes into account the GHG emissions embedded in different goods and services. The paper depicts that, while the direct emissions from transportation and housing energy slightly decrease with higher density, the reductions can be easily overridden by sources of indirect emissions. We also highlight that the indirect emissions actually seem to have strong structural determinants, often undermined in studies concerning sustainable urban forms. Further, we introduce a concept of ‘parallel consumption’ to explain how the lifestyles especially in more urbanized areas lead to multiplication of consumption outside of the limits of time budget and the living environment. This is also part I of a two-stage study. In part II we will depict how various other contextual and socioeconomic variables are actually also very important to take into account, and how diverse GHG mitigation strategies would be needed for different types of area in different locations towards a low-carbon future.

Is Traffic Still an Important Emitter of Monoaromatic Organic Compounds in European Urban Areas?

PubMed

Borbon, Agnès; Boynard, Anne; Salameh, Thérèse; Baudic, Alexia; Gros, Valérie; Gauduin, Julie; Perrussel, Olivier; Pallares, Cyril

2018-01-16

Trends of long-term observations and emission inventories suggest that traffic emissions will no longer dominate the concentrations of monoaromatic compounds (i.e., TEX - toluene, xylenes, and ethylbenzene) in European urban areas. But the split limit between traffic and other emission sector contributions such as solvent use remains tenuous. Here long-term observations of an extensive set of hydrocarbons, including TEX, at traffic and urban background sites in London, Paris and Strasbourg were combined to estimate the relative importance of traffic emissions on TEX in every city. When analyzing the urban enhancement emission ratios of TEX-to-benzene on a seasonal basis, two potential source signatures other than traffic could be differentiated in all cities (1) summertime evaporation from fuel and/or solvent and (2) wintertime domestic heating. However, traffic emissions still unambiguously dominate the concentration levels of TEX in every city despite the reduction of their emissions at exhaust pipe over the last two decades. Traffic explains between 60% and 96% (at ±20%) of TEX levels while it is less clear for xylenes at some locations. Our results provide a basis to evaluate regional emission inventories. The method is applicable at any urban area where speciated hydrocarbon monitoring is available.

Dynamic impact of urbanization, economic growth, energy consumption, and trade openness on CO 2 emissions in Nigeria.

PubMed

Ali, Hamisu Sadi; Law, Siong Hook; Zannah, Talha Ibrahim

2016-06-01

The objective of this paper is to examine the dynamic impact of urbanization, economic growth, energy consumption, and trade openness on CO 2 emissions in Nigeria based on autoregressive distributed lags (ARDL) approach for the period of 1971-2011. The result shows that variables were cointegrated as null hypothesis was rejected at 1 % level of significance. The coefficients of long-run result reveal that urbanization does not have any significant impact on CO 2 emissions in Nigeria, economic growth, and energy consumption has a positive and significant impact on CO 2 emissions. However, trade openness has negative and significant impact on CO 2 emissions. Consumption of energy is among the main determinant of CO 2 emissions which is directly linked to the level of income. Despite the high level of urbanization in the country, consumption of energy still remains low due to lower income of the majority populace and this might be among the reasons why urbanization does not influence emissions of CO 2 in the country. Initiating more open economy policies will be welcoming in the Nigerian economy as the openness leads to the reduction of pollutants from the environment particularly CO 2 emissions which is the major gases that deteriorate physical environment.

Ammonia in London: is it increasing and what is the relevance of urban ammonia for air quality impacts?

NASA Astrophysics Data System (ADS)

Braban, Christine; Tang, Sim; Poskitt, Janet; Van Dijk, Netty; Leeson, Sarah; Dragosits, Ulli; Hutchings, Torben; Twigg, Marsailidh; Di Marco, Chiara; Langford, Ben; Tremper, Anja; Nemitz, Eiko; Sutton, Mark

2017-04-01

Emissions of ammonia affect both rural and urban air quality primarily via reaction of ammonia in the atmosphere forming secondary ammonium salts in particulate matter (PM). Urban ammonia emissions come from a variety of sources including biological decomposition, human waste, industrial processes and combustion engines. In the UK, the only long-term urban ammonia measurement is a UK National Ammonia Monitoring Network site at London Cromwell Road, recording monthly average concentrations. Short term measurements have also been made in the past decade at Marylebone Road, North Kensington and on the BT Tower. Cromwell Road is a kerbside site operational since 1999. The Cromwell Road data indicates that ammonia concentrations may be increasing since 2010-2012 after a long period of decreasing. Data from the National Atmospheric Emissions Inventory indicates ammonia emissions from diesel fleet exhausts increasing over this time period but an overall net decrease in ammonia emissions. With changes in engine and exhaust technology to minimise pollutant emissions and the importance of ammonia as a precursor gas for secondary PM, there is a challenge to understand urban ammonia concentrations and subsequent impacts on urban air quality. In this paper the long term measurements are assessed in conjunction with the short-term measurements.The challenges to assess the relative importance of local versus long range ammonia emission are discussed.

EMISSIONS PROFILE CHARACTERIZATION OF LAKE MICHIGAN POLLUTANT SOURCES - PART I

EPA Science Inventory

The southern Lake Michigan aea continues to experience poor air quality despite the implementation of many measures to control particulate matter, ozone and toxic pollutants. Fortunately, the ambient atmosphere holds clues tothese sources and their contributions to urban polluti...

1990 Clean Air Act Amendment Summary: Title IV

EPA Pesticide Factsheets

This page provides an overview of the 1990 amendments to Title IV of the Clean Air Act, which were enacted to curb acid rain, urban air pollution and toxic air emissions. The edits to this title deal with acid deposition control.

Tool for assessing health and equity impacts of interventions modifying air quality in urban environments.

PubMed

Cartier, Yuri; Benmarhnia, Tarik; Brousselle, Astrid

2015-12-01

Urban outdoor air pollution (AP) is a major public health concern but the mechanisms by which interventions impact health and social inequities are rarely assessed. Health and equity impacts of policies and interventions are questioned, but managers and policy agents in various institutional contexts have very few practical tools to help them better orient interventions in sectors other than the health sector. Our objective was to create such a tool to facilitate the assessment of health impacts of urban outdoor AP interventions by non-public health experts. An iterative process of reviewing the academic literature, brainstorming, and consultation with experts was used to identify the chain of effects of urban outdoor AP and the major modifying factors. To test its applicability, the tool was applied to two interventions, the London Low Emission Zone and the Montréal BIXI public bicycle-sharing program. We identify the chain of effects, six categories of modifying factors: those controlling the source of emissions, the quantity of emissions, concentrations of emitted pollutants, their spatial distribution, personal exposure, and individual vulnerability. Modifiable and non-modifiable factors are also identified. Results are presented in the text but also graphically, as we wanted it to be a practical tool, from pollution sources to emission, exposure, and finally, health effects. The tool represents a practical first step to assessing AP-related interventions for health and equity impacts. Understanding how different factors affect health and equity through air pollution can provide insight to city policymakers pursuing Health in All Policies. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Using OCO-2 Observations and Lagrangian Modeling to Constrain Urban Carbon Dioxide Emissions in the Middle East

NASA Astrophysics Data System (ADS)

Yang, E. G.; Kort, E. A.; Ware, J.; Ye, X.; Lauvaux, T.; Wu, D.; Lin, J. C.; Oda, T.

2017-12-01

Anthropogenic carbon dioxide (CO2) emissions are greatly perturbing the Earth's carbon cycle. Rising emissions from the developing world are increasing uncertainties in global CO2 emissions. With the rapid urbanization of developing regions, methods of constraining urban CO2 emissions in these areas can address critical uncertainties in the global carbon budget. In this study, we work toward constraining urban CO2 emissions in the Middle East by comparing top-down observations and bottom-up simulations of total column CO2 (XCO2) in four cities (Riyadh, Cairo, Baghdad, and Doha), both separately and in aggregate. This comparison involves quantifying the relationship for all available data in the period of September 2014 until March 2016 between observations of XCO2 from the Orbiting Carbon Observatory-2 (OCO-2) satellite and simulations of XCO2 using the Stochastic Time-Inverted Lagrangian Transport (STILT) model coupled with Global Data Assimilation System (GDAS) reanalysis products and multiple CO2 emissions inventories. We discuss the extent to which our observation/model framework can distinguish between the different emissions representations and determine optimized emissions estimates for this domain. We also highlight the implications of our comparisons on the fidelity of the bottom-up inventories used, and how these implications may inform the use of OCO-2 data for urban regions around the world.

Secondary organic aerosol production from diesel vehicle exhaust: impact of aftertreatment, fuel chemistry and driving cycle

NASA Astrophysics Data System (ADS)

Gordon, T. D.; Presto, A. A.; Nguyen, N. T.; Robertson, W. H.; Na, K.; Sahay, K. N.; Zhang, M.; Maddox, C.; Rieger, P.; Chattopadhyay, S.; Maldonado, H.; Maricq, M. M.; Robinson, A. L.

2013-09-01

Environmental chamber ("smog chamber") experiments were conducted to investigate secondary organic aerosol (SOA) production from dilute emissions from two medium-duty diesel vehicles (MDDVs) and three heavy-duty diesel vehicles (HDDVs) under urban-like conditions. Some of the vehicles were equipped with emission control aftertreatment devices including diesel particulate filters (DPF), selective catalytic reduction (SCR) and diesel oxidation catalysts (DOC). Experiments were also performed with different fuels (100% biodiesel and low-, medium- or high-aromatic ultralow sulfur diesel) and driving cycles (Unified Cycle, Urban Dynamometer Driving Schedule, and creep+idle). During normal operation, vehicles with a catalyzed DPF emitted very little primary particulate matter (PM). Furthermore, photo-oxidation of dilute emissions from these vehicles produced essentially no SOA (below detection limit). However, significant primary PM emissions and SOA production were measured during active DPF regeneration experiments. Nevertheless, under reasonable assumptions about DPF regeneration frequency, the contribution of regeneration emissions to the total vehicle emissions is negligible, reducing PM trapping efficiency by less than 2%. Therefore, catalyzed DPFs appear to be very effective in reducing both primary and secondary fine particulate matter from diesel vehicles. For both MDDVs and HDDVs without aftertreatment substantial SOA formed in the smog chamber - with the emissions from some vehicles generating twice as much SOA as primary organic aerosol after three hours of oxidation at typical urban VOC : NOx ratios (3:1). Comprehensive organic gas speciation was performed on these emissions, but less than half of the measured SOA could be explained by traditional (speciated) SOA precursors. The remainder presumably originates from the large fraction (~30%) of the non-methane organic gas emissions that could not be speciated using traditional one-dimensional gas-chromatography. The unspeciated organics - likely comprising less volatile species, such as intermediate volatility organic compounds - appear to be important SOA precursors; we estimate that the effective SOA yield (defined as the ratio of SOA mass to reacted precursor mass) was 9 ± 6% if both speciated SOA precursors and unspeciated organics are included in the analysis. SOA production from creep+idle operation was 3-4 times larger than SOA production from the same vehicle operated over the Urban Dynamometer Driving Schedule (UDDS). Fuel properties had little or no effect on primary PM emissions or SOA formation.

Urban greening impacts on tropospheric ozone

NASA Astrophysics Data System (ADS)

Grote, R.; Churkina, G.; Butler, T. M.; Morfopoulos, C.

2013-12-01

Cities are characterized by elevated air temperatures as well as high anthropogenic emissions of air pollutants. Cities' greening in form of urban parks, street trees, and vegetation on roofs and walls of buildings is supposed to generally mitigate negative impacts on human health and well-being. However, high emissions of biogenic volatile organic compounds (BVOC) from certain popular urban plants in combination with the elevated concentrations of NOx have the potential to increase ground-level ozone concentrations - with negative impacts on health, agriculture, and climate. Policies targeting reduction of ground-level ozone in urban and suburban areas therefore must consider limiting BVOC emissions along with measures for decreasing NOx and VOC from anthropogenic sources. For this, integrated climate/ chemistry models are needed that take into account the species-specific physiological responses of urban plants which in turn drive their emission behavior. Current models of urban climate and air quality 1) do not account for the feedback between ozone concentrations, productivity, and BVOC emission and 2) do not distinguish different physiological properties of urban tree species. Instead environmental factors such as light, temperature, carbon dioxide, and water supply are applied disregarding interactions between such influences. Thus we may not yet be able to represent the impacts of air pollution under multiple changed conditions such as climate change, altered anthropogenic emission patterns, and new urban structures. We present here the implementation of the new BVOC emission model (Morfopolous et al., in press) that derives BVOC emissions directly from the electron production potential and consumption from photosynthesis calculation that is already supplied by the CLM land surface model. The new approach has the advantage that many environmental drivers of BVOC emissions are implicitly considered in the description of plant photosynthesis and phenology. We investigate the tradeoff between vegetation driven ozone -reduction and -formation processes in dependence on temperature, radiation, CO2 and O3 concentrations. We have parameterized suitable plant functional types for different urban greening structures, currently focusing on central European vegetation. The modified CLM model is applied in a global (CESM) and a regional climate/ air quality model (WRF-Chem) to calculate realistic ozone concentrations in the influence zones of urban conglomerations. BVOC emissions and their impacts are also calculated with the standard MEGAN2.1 approach for comparison. The simulation results are analyzed and discussed in view of the models suitability for air quality scenario estimates under simultaneously changing climate, anthropogenic emissions and plant species composition. References Morfopoulos, C., Prentice, I.C., Keenan T.F., Friedlingstein, P., Medlyn, B., Penuelas, J., Possel, M. (in press): A unifying conceptual model for the environmental responses of isoprene emission by plants. Annals of Botany

Source apportionment of fine particles and its chemical components over the Yangtze River Delta, China during a heavy haze pollution episode

NASA Astrophysics Data System (ADS)

Li, L.; An, J. Y.; Zhou, M.; Yan, R. S.; Huang, C.; Lu, Q.; Lin, L.; Wang, Y. J.; Tao, S. K.; Qiao, L. P.; Zhu, S. H.; Chen, C. H.

2015-12-01

An extremely high PM2.5 pollution episode occurred over the eastern China in January 2013. In this paper, the particulate matter source apportionment technology (PSAT) method coupled within the Comprehensive air quality model with extensions (CAMx) is applied to study the source contributions to PM2.5 and its major components at six receptors (Urban Shanghai, Chongming, Dianshan Lake, Urban Suzhou, Hangzhou and Zhoushan) in the Yangtze River Delta (YRD) region. Contributions from 4 source areas (including Shanghai, South Jiangsu, North Zhejiang and Super-region) and 9 emission sectors (including power plants, industrial boilers and kilns, industrial processing, mobile source, residential, volatile emissions, dust, agriculture and biogenic emissions) to PM2.5 and its major components (sulfate, nitrate, ammonia, organic carbon and elemental carbon) at the six receptors in the YRD region are quantified. Results show that accumulation of local pollution was the largest contributor during this air pollution episode in urban Shanghai (55%) and Suzhou (46%), followed by long-range transport (37% contribution to Shanghai and 44% to Suzhou). Super-regional emissions play an important role in PM2.5 formation at Hangzhou (48%) and Zhoushan site (68%). Among the emission sectors contributing to the high pollution episode, the major source categories include industrial processing (with contributions ranging between 12.7 and 38.7% at different receptors), combustion source (21.7-37.3%), mobile source (7.5-17.7%) and fugitive dust (8.4-27.3%). Agricultural contribution is also very significant at Zhoushan site (24.5%). In terms of the PM2.5 major components, it is found that industrial boilers and kilns are the major source contributor to sulfate and nitrate. Volatile emission source and agriculture are the major contributors to ammonia; transport is the largest contributor to elemental carbon. Industrial processing, volatile emissions and mobile source are the most significant contributors to organic carbon. Results show that the Yangtze River Delta region should focus on the joint pollution control of industrial processing, combustion emissions, mobile source emissions, and fugitive dust. Regional transport of air pollution among the cities are prominent, and the implementation of regional joint prevention and control of air pollution will help to alleviate fine particulate matter concentrations under heavy pollution case significantly.

Urban Household Carbon Emission and Contributing Factors in the Yangtze River Delta, China

PubMed Central

Xu, Xibao; Tan, Yan; Chen, Shuang; Yang, Guishan; Su, Weizhong

2015-01-01

Carbon reduction at the household level is an integral part of carbon mitigation. This study analyses the characteristics, effects, contributing factors and policies for urban household carbon emissions in the Yangtze River Delta of China. Primary data was collected through structured questionnaire surveys in three cities in the region – Nanjing, Ningbo, and Changzhou in 2011. The survey data was first used to estimate the magnitude of household carbon emissions in different urban contexts. It then examined how, and to what extent, each set of demographic, economic, behavioral/cognitive and spatial factors influence carbon emissions at the household level. The average of urban household carbon emissions in the region was estimated to be 5.96 tonnes CO2 in 2010. Energy consumption, daily commuting, garbage disposal and long-distance travel accounted for 51.2%, 21.3%, 16.0% and 11.5% of the total emission, respectively. Regulating rapidly growing car-holdings of urban households, stabilizing population growth, and transiting residents’ low-carbon awareness to household behavior in energy saving and other spheres of consumption in the context of rapid population aging and the growing middle income class are suggested as critical measures for carbon mitigation among urban households in the Yangtze River Delta. PMID:25884853

The Contribution of On-Road Emissions of Ammonia to Atmospheric Nitrogen Deposition

NASA Astrophysics Data System (ADS)

Fenn, M. E.; Schilling, S.; Bytnerowicz, A.; Bell, M. D.; Sickman, J. O.; Hanks, K.; Geiser, L.

2017-12-01

Emissions control technologies for NOx result in increased production of NH3. Emissions inventories and simulated deposition of NHx frequently underestimate reduced forms of N. Herein we provide updated spatial distribution and inventory data for on-road NH3 emissions for the continental U.S. On-road NH3 emissions were determined from on-road CO2 emissions data and published empirical NH3:CO2 vehicle emissions ratios. Emissions of NH3 in urbanized regions are typically 0.1 - 1.3 t/km2/yr. By comparison, NH3 emissions in agricultural regions generally range from 0.4 - 5.5 t/km2/yr, with a few hotspots as high as 5.5 - 11.2 t/km2/yr. We identified 500 counties that receive at least 30% of the NH3 emissions from on-road sources. Counties with higher vehicle NH3 emissions than from agriculture include 41% of the U.S. population. Within CONUS the percent of wet inorganic N deposition from the NADP/NTN as NH4+ ranged from 37 to 83% with a mean of 59.5%. Only 13% of the NADP sites across the U.S. had less than 45% of the N deposition as NH4+ based on data from 2014-2016, illustrating the near-universal occurrence of NH4+ deposition across the U.S., regardless of the primary sources of NH3 emissions. The relative importance of urban and on-road NH3 emissions versus emissions from agriculture varies regionally. In some areas both are important and should be considered when evaluating the principal sources of N deposition to affected ecosystems.Case studies of on-road NH3 emissions in relation to N deposition include four urban sites in Oregon and Washington where the NH4-N:NO3-N ratio in throughfall was 1.0 compared to an average ratio of 2.3 in bulk deposition. At urban sites in the Los Angeles Basin bulk deposition of NH4-N and NO3-N were equivalent, while NH4-N:NO3-N in throughfall under shrubs in the greater LA Basin ranged from 0.7 to 1.5. The NH4-N:NO3-N ratio at ten sites in the Lake Tahoe Basin averaged 1.4 and 1.6 in bulk deposition and throughfall. Throughfall and bulk deposition of NH4-N was strongly correlated with summertime NH3 concentrations and values of δ15NH4+ in deposition samples in the Tahoe Basin were predominantly within the range of -5.0 to -0.9‰, indicative of tailpipe NH3 emissions. On-road emissions of NH3 should not be ignored as important precursors of particulate pollution and as a source of N deposition.

Bright is the new black—multi-year performance of high-albedo roofs in an urban climate

NASA Astrophysics Data System (ADS)

Gaffin, S. R.; Imhoff, M.; Rosenzweig, C.; Khanbilvardi, R.; Pasqualini, A.; Kong, A. Y. Y.; Grillo, D.; Freed, A.; Hillel, D.; Hartung, E.

2012-03-01

High-albedo white and cool roofing membranes are recognized as a fundamental strategy that dense urban areas can deploy on a large scale, at low cost, to mitigate the urban heat island effect. We are monitoring three generic white membranes within New York City that represent a cross section of the dominant white membrane options for US flat roofs: (1) an ethylene-propylene-diene monomer (EPDM) rubber membrane; (2) a thermoplastic polyolefin (TPO) membrane; and (3) an asphaltic multi-ply built-up membrane coated with white elastomeric acrylic paint. The paint product is being used by New York City’s government for the first major urban albedo enhancement program in its history. We report on the temperature and related albedo performance of these three membranes at three different sites over a multi-year period. The results indicate that the professionally installed white membranes are maintaining their temperature control effectively and are meeting the Energy Star Cool Roofing performance standards requiring a three-year aged albedo above 0.50. The EPDM membrane shows evidence of low emissivity; however this had the interesting effect of avoiding any ‘winter heat penalty’ for this building. The painted asphaltic surface shows high emissivity but lost about half of its initial albedo within two years of installation. Given that the acrylic approach is such an important ‘do-it-yourself’, low-cost, retrofit technique, and, as such, offers the most rapid technique for increasing urban albedo, further product performance research is recommended to identify conditions that optimize its long-term albedo control. Even so, its current multi-year performance still represents a significant albedo enhancement for urban heat island mitigation.

Spatial and temporal variability in greenhouse gas abundance of urban streams: The role of urban infrastructure

EPA Science Inventory

Background/Question/MethodsStreams and rivers are significant sources of greenhouse gas emissions globally. Water quality and watershed management, are likely to influence GHG emissions regionally. In urban-impacted watersheds, increased nitrogen loading, organic matter, and war...

Effects of land cover change on litter decomposition and soil greenhouse gas fluxes in subtropical Hong Kong

NASA Astrophysics Data System (ADS)

Ngar Wong, Chun; Lai, Derrick Yuk Fo

2017-04-01

Nowadays, over 50% of the world's population live in urbanized areas and the level of urbanization varies substantially across countries. Intense human activities and management associated with urbanization can alter the microclimate and biogeochemical processes in urban areas, which subsequently affect the provision of ecosystem services and functions. Litter decomposition and soil greenhouse gas (GHG) exchange play an important role in governing nutrient cycling and future climate change, respectively. Yet, the effects of urbanization on these two biogeochemical processes remain uncertain and not well understood, especially in subtropical and high-density cities. This study aims to examine the effects of urbanization on decomposition and GHG fluxes among four land covers- natural forest, urban forest, farmland and roadside planter, in Hong Kong based on litterbag experiment and closed chamber measurements for one full year. Litter decomposition rate was significantly lower in farmland than in other land cover types. Significant differences in CO2 emission were detected among the four land cover types (p<0.05), with the highest and lowest CO2 emissions being recorded in farmland and roadside planter, respectively. CH4 emission varied significantly among the land covers as well (p<0.05), with the highest and lowest CH4 emissions being recorded in farmland and urban forest, respectively. Farmland and urban forest showed the highest and lowest mean N2O fluxes, respectively. The emission of CO2 was positively correlated with soil potassium content, while CH4 and N2O flux increased markedly with soil temperature and nitrate nitrogen content, respectively. The results obtained in this study will enhance our understanding on urban ecosystem and be useful for recommending sustainable management strategies for conservation of ecosystem services in urban areas.

EMISSIONS PROFILE CHARACTERIZATION OF LAKE MICHIGAN POLLUTANT SOURCES - PART III

EPA Science Inventory

The southern Lake Michigan aea continues to experience poor air quality despite the implementation of many measures to control particulate matter, ozone and toxic pollutants. Fortunately, the ambient atmosphere holds clues to these sources and their contributions to urban polluti...

EMISSIONS PROFILE CHARACTERIZATION OF LAKE MICHIGAN POLLUTANT SOURCES - PART II

EPA Science Inventory

The southern Lake Michigan area continues to experience poor air quality despite the implementation of many measures to control particulate matter, ozone and toxic pollutants. Fortunately, the ambient atmosphere holds clues to these sources and their contributions to urban pollut...

78 FR 922 - Revisions to the California State Implementation Plan, Imperial County Air Pollution Control...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-07

... ) emissions from sources of fugitive dust such as unpaved roads and disturbed soils in open and agricultural... trespass and stabilize disturbed soil on open areas larger than 0.5 acres in urban areas, and larger than...

Assembling a biogenic hydrocarbon emissions inventory for the SCOS97-NARSTO modeling domain

DOE Office of Scientific and Technical Information (OSTI.GOV)

Benjamin, M.T.; Winer, A.M.; Karlik, J.

1998-12-31

To assist in developing ozone control strategies for Southern California, the California Air Resources Board is developing a biogenic hydrocarbon (BHC) emissions inventory model for the SCOS97-NARSTO domain. The basis for this bottom-up model is SCOS97-NARSTO-specific landuse and landcover maps, leafmass constants, and BHC emission rates. In urban areas, landuse maps developed by the Southern California Association of Governments, San Diego Association of Governments, and other local governments are used while in natural areas, landcover and plant community databases produced by the GAP Analysis Project (GAP) are employed. Plant identities and canopy volumes for species in each landuse and landcovermore » category are based on the most recent botanical field survey data. Where possible, experimentally determined leafmass constant and BHC emission rate measurements reported in the literature are used or, for those species where experimental data are not available, values are assigned based on taxonomic methods. A geographic information system is being used to integrate these databases, as well as the most recent environmental correction algorithms and canopy shading factors, to produce a spatially- and temporally-resolved BHC emission inventory suitable for input into the Urban Airshed Model.« less

A multi-scale approach to monitor urban carbon-dioxide emissions in the atmosphere over Vancouver, Canada

NASA Astrophysics Data System (ADS)

Christen, A.; Crawford, B.; Ketler, R.; Lee, J. K.; McKendry, I. G.; Nesic, Z.; Caitlin, S.

2015-12-01

Measurements of long-lived greenhouse gases in the urban atmosphere are potentially useful to constrain and validate urban emission inventories, or space-borne remote-sensing products. We summarize and compare three different approaches, operating at different scales, that directly or indirectly identify, attribute and quantify emissions (and uptake) of carbon dioxide (CO2) in urban environments. All three approaches are illustrated using in-situ measurements in the atmosphere in and over Vancouver, Canada. Mobile sensing may be a promising way to quantify and map CO2 mixing ratios at fine scales across heterogenous and complex urban environments. We developed a system for monitoring CO2 mixing ratios at street level using a network of mobile CO2 sensors deployable on vehicles and bikes. A total of 5 prototype sensors were built and simultaneously used in a measurement campaign across a range of urban land use types and densities within a short time frame (3 hours). The dataset is used to aid in fine scale emission mapping in combination with simultaneous tower-based flux measurements. Overall, calculated CO2 emissions are realistic when compared against a spatially disaggregated scale emission inventory. The second approach is based on mass flux measurements of CO2 using a tower-based eddy covariance (EC) system. We present a continuous 7-year long dataset of CO2 fluxes measured by EC at the 28m tall flux tower 'Vancouver-Sunset'. We show how this dataset can be combined with turbulent source area models to quantify and partition different emission processes at the neighborhood-scale. The long-term EC measurements are within 10% of a spatially disaggregated scale emission inventory. Thirdly, at the urban scale, we present a dataset of CO2 mixing ratios measured using a tethered balloon system in the urban boundary layer above Vancouver. Using a simple box model, net city-scale CO2 emissions can be determined using measured rate of change of CO2 mixing ratios, estimated CO2 advection and entrainment fluxes. Daily city-scale emissions totals predicted by the model are within 32% of a spatially scaled municipal greenhouse gas inventory. In summary, combining information from different approaches and scales is a promising approach to establish long-term emission monitoring networks in cities.

Informing urban carbon emissions with atmospheric observations: motivation, methods, and reducing uncertainties.

NASA Astrophysics Data System (ADS)

Kort, E. A.; Ware, J.; Duren, R. M.; Schimel, D.; Miller, C. E.; Decola, P.

2014-12-01

Urban regions play a dominant role in the anthropogenic perturbation to atmospheric carbon dioxide and methane. With increasing urbanization (notably in developing nations) and increasing emissions, quantitative observational information on emissions of CO2 and CH4 becomes critical for improved understanding of the global carbon cycle and for carbon management/policy decisions. In this presentation, we will discuss the impact uncertainty in anthropogenic emissions has on global carbon-climate understanding, providing broad geophysical motivation for urban studies. We will further discuss observations of urban regions at different scales (satellite vs. in-situ), and investigate the information content of these complementary methods for answering targeted questions on both global carbon fluxes and regional management decisions. Finally, we will present new attempts at reducing uncertainty in high-resolution inversions leveraging remotely sensed aerosol profiles to constrain both mixing depths and vertical distributions of trace gases.

Testing CMAQ chemistry sensitivities in base case and emissions control runs at SEARCH and SOS99 surface sites in the southeastern US

NASA Astrophysics Data System (ADS)

Arnold, J. R.; Dennis, Robin L.

CMAQ was run to simulate urban and regional tropospheric conditions in the southeastern US over 14 days in July 1999 at 32, 8 and 2 km grid spacings. Runs were made with either of two older mechanisms, Carbon Bond IV (CB4) and the Regional Acid Deposition Model, version 2 (RADM2), and with the more recent and complete California Statewide Air Pollution Research Center, version 1999 mechanism (SAPRC99) in a sensitivity matrix with a full emissions base case and separate 50% control scenarios for emissions of nitrogen oxides (NO X) and volatile organic compounds (VOC). Results from the base case were compared to observations at the Southeastern Aerosol Research and Characterization Study (SEARCH) site at Jefferson Street in Atlanta, GA (JST) and the Southern Oxidant Study (SOS) Cornelia Fort Airpark (CFA) site downwind of Nashville, TN. In the base case, SAPRC99 predicted more ozone (O 3) than CB4 or RADM2 almost every hour and especially for afternoon maxima at both JST and CFA. Performance of the 8 km models at JST was better than that of the 32 km ones for all chemistries, reducing the 1 h peak bias by as much as 30 percentage points; at CFA only the RADM2 8 km model improved. The 2 km solutions did not show improved performance over the 8 km ones at either site, with normalized 1 h bias in the peak O 3 ranging from 21% at CFA to 43% at JST. In the emissions control cases, SAPRC99 was generally more responsive than CB4 and RADM2 to NO X and VOC controls, excepting hours at JST with predicted increased O 3 from NO X control. Differential sensitivity to chemical mechanism varied by more than ±10% for NO X control at JST and CFA, and in a similar range for VOC control at JST. VOC control at the more strongly NO X- limited urban CFA site produced a differential sensitivity response of <5%. However, even when differential sensitivities in control cases were small, neither their sign nor their magnitude could be reliably determined from model performance in the full emissions case, meaning that the degree of O 3 response to a change in chemical mechanism can differ substantially with the level of precursor emissions. Hence we conclude that properly understanding the effects of changes in a model's chemical mechanism always requires emissions control cases as part of model sensitivity analysis.

Identification of the sources of primary organic aerosols at urban schools: a molecular marker approach.

PubMed

Crilley, Leigh R; Qadir, Raeed M; Ayoko, Godwin A; Schnelle-Kreis, Jürgen; Abbaszade, Gülcin; Orasche, Jürgen; Zimmermann, Ralf; Morawska, Lidia

2014-08-01

Children are particularly susceptible to air pollution and schools are examples of urban microenvironments that can account for a large portion of children's exposure to airborne particles. Thus this paper aimed to determine the sources of primary airborne particles that children are exposed to at school by analyzing selected organic molecular markers at 11 urban schools in Brisbane, Australia. Positive matrix factorization analysis identified four sources at the schools: vehicle emissions, biomass burning, meat cooking and plant wax emissions accounting for 45%, 29%, 16% and 7%, of the organic carbon respectively. Biomass burning peaked in winter due to prescribed burning of bushland around Brisbane. Overall, the results indicated that both local (traffic) and regional (biomass burning) sources of primary organic aerosols influence the levels of ambient particles that children are exposed at the schools. These results have implications for potential control strategies for mitigating exposure at schools. Copyright © 2014 Elsevier Ltd. All rights reserved.

Reducing secondary organic aerosol formation from gasoline vehicle exhaust

PubMed Central

Zhao, Yunliang; Saleh, Rawad; Presto, Albert A.; Gordon, Timothy D.; Drozd, Greg T.; Goldstein, Allen H.; Robinson, Allen L.

2017-01-01

On-road gasoline vehicles are a major source of secondary organic aerosol (SOA) in urban areas. We investigated SOA formation by oxidizing dilute, ambient-level exhaust concentrations from a fleet of on-road gasoline vehicles in a smog chamber. We measured less SOA formation from newer vehicles meeting more stringent emissions standards. This suggests that the natural replacement of older vehicles with newer ones that meet more stringent emissions standards should reduce SOA levels in urban environments. However, SOA production depends on both precursor concentrations (emissions) and atmospheric chemistry (SOA yields). We found a strongly nonlinear relationship between SOA formation and the ratio of nonmethane organic gas to oxides of nitrogen (NOx) (NMOG:NOx), which affects the fate of peroxy radicals. For example, changing the NMOG:NOx from 4 to 10 ppbC/ppbNOx increased the SOA yield from dilute gasoline vehicle exhaust by a factor of 8. We investigated the implications of this relationship for the Los Angeles area. Although organic gas emissions from gasoline vehicles in Los Angeles are expected to fall by almost 80% over the next two decades, we predict no reduction in SOA production from these emissions due to the effects of rising NMOG:NOx on SOA yields. This highlights the importance of integrated emission control policies for NOx and organic gases. PMID:28630318

"Fingerprinting" Vehicle Derived Ammonia Utilizing Nitrogen Stable Isotopes

NASA Astrophysics Data System (ADS)

Walters, W.; Hastings, M. G.; Colombi, N. K.

2017-12-01

Ammonia (NH3) is the primary alkaline molecule in the atmosphere and plays a key role in numerous atmospheric processes that have important implications for human health and climate control. While agriculture activities dominate the global NH3 budget, there are large uncertainties in the urban NH3 emission inventories. The analysis of the nitrogen stable isotope composition of NH3 (δ15N-NH3) might be a useful tool for partitioning NH3 emission sources, as different emission sources tend to emit NH3 with distinctive δ15N signatures or "fingerprints". This novel tool may help improve upon urban emission inventories, which could help to improve modeling of important atmospheric processes involving NH3. However, there is a current lack of δ15N-NH3 measurements of potentially important urban NH3 emission sources, and many of the reported NH3 collection methods have not been verified for its ability to accurately characterize δ15N-NH3. Here we present a laboratory tested method to accurately measure δ15N-NH3 using honeycomb denuders coated with a 2% citric acid solution. Based on laboratory tests, the NH3 collection device has been optimized under a variety of conditions. Near quantitative NH3 collection is found at a sampling rate of 10 SLPM for NH3 concentrations less than 2 ppmv, and δ15N-NH3 precision is found to be approximately 1.0‰. This newly developed NH3 collection device for isotopic characterization has been applied to improve our understanding of the δ15N-NH3 signatures from vehicles. Preliminary results of NH3 collected near a road-side indicate an average δ15N-NH3 of -2.1 ± 1.9‰. This work is ongoing, and plans are in place to collect NH3 directly from tailpipes and from on-road air. Our preliminary results indicate that vehicle derived NH3 has a distinctive δ15N signature compared to agricultural and waste emissions; thus, δ15N(NH3) has the potential to be used to understand urban NH3 emission sources.

Observed trends in ambient concentrations of C 2-C 8 hydrocarbons in the United Kingdom over the period from 1993 to 2004

NASA Astrophysics Data System (ADS)

Dollard, G. J.; Dumitrean, P.; Telling, S.; Dixon, J.; Derwent, R. G.

Hourly measurements of up to 26 C 2-C 8 hydrocarbons have been made at eight urban background sites, three urban-industrial sites, a kerbside and a rural site in the UK from 1993 onwards up until the end of December 2004. Average annual mean benzene and 1,3-butadiene concentrations at urban background locations have declined at about -20% per year and the observed declines have exactly mimicked the inferred declines in benzene and 1,3-butadiene emissions over the same period. Ninety-day rolling mean concentrations of ethylene, propylene, n- and i-butane, n- and i-pentane, isoprene and propane at urban and rural sites have also declined steadily by between -10% and -30% per year. Rolling mean concentrations of acetylene, 2- and 3-methylpentane, n-hexane, n-heptane, cis- and trans-but-2-ene, cis- and trans-pent-2-ene, toluene, ethylbenzene and o-, m- and p-xylene at a roadside location in London have all declined at between -14% and -21% per year. These declines demonstrate that motor vehicle exhaust catalysts and evaporative canisters have effectively and efficiently controlled vehicular emissions of hydrocarbons in the UK. Urban ethane concentrations arising largely from natural gas leakage have remained largely unchanged over this same period.

The comparison of fossil carbon fraction and greenhouse gas emissions through an analysis of exhaust gases from urban solid waste incineration facilities.

PubMed

Kim, Seungjin; Kang, Seongmin; Lee, Jeongwoo; Lee, Seehyung; Kim, Ki-Hyun; Jeon, Eui-Chan

2016-10-01

In this study, in order to understand accurate calculation of greenhouse gas emissions of urban solid waste incineration facilities, which are major waste incineration facilities, and problems likely to occur at this time, emissions were calculated by classifying calculation methods into 3 types. For the comparison of calculation methods, the waste characteristics ratio, dry substance content by waste characteristics, carbon content in dry substance, and (12)C content were analyzed; and in particular, CO2 concentration in incineration gases and (12)C content were analyzed together. In this study, 3 types of calculation methods were made through the assay value, and by using each calculation method, emissions of urban solid waste incineration facilities were calculated then compared. As a result of comparison, with Calculation Method A, which used the default value as presented in the IPCC guidelines, greenhouse gas emissions were calculated for the urban solid waste incineration facilities A and B at 244.43 ton CO2/day and 322.09 ton CO2/day, respectively. Hence, it showed a lot of difference from Calculation Methods B and C, which used the assay value of this study. It is determined that this was because the default value as presented in IPCC, as the world average value, could not reflect the characteristics of urban solid waste incineration facilities. Calculation Method B indicated 163.31 ton CO2/day and 230.34 ton CO2/day respectively for the urban solid waste incineration facilities A and B; also, Calculation Method C indicated 151.79 ton CO2/day and 218.99 ton CO2/day, respectively. This study intends to compare greenhouse gas emissions calculated using (12)C content default value provided by the IPCC (Intergovernmental Panel on Climate Change) with greenhouse gas emissions calculated using (12)C content and waste assay value that can reflect the characteristics of the target urban solid waste incineration facilities. Also, the concentration and (12)C content were calculated by directly collecting incineration gases of the target urban solid waste incineration facilities, and greenhouse gas emissions of the target urban solid waste incineration facilities through this survey were compared with greenhouse gas emissions, which used the previously calculated assay value of solid waste.

ROLE OF MODELS IN AIR QUALITY MANAGEMENT DECISIONS

EPA Science Inventory

Within the frame of the US-India bilateral agreement on environmental cooperation, a team of US scientists have been helping India in designing emission control policies to address urban air quality problems. This presentation discusses how air quality models need to be used for ...

Incidence of real-world automotive parent and halogenated PAH in urban atmosphere.

PubMed

Gao, Pan-Pan; Zhao, Yi-Bo; Ni, Hong-Gang

2018-06-01

This study reports results from a tunnel experiment impact of real-world traffic-related particle and gas parent and halogenated polycyclic aromatic hydrocarbons (PAHs and HPAHs) on urban air. The traffic related emission characteristics and subsequent environmental behavior of these compounds were investigated. To understand the significance of real-world transport emissions to the urban air, traffic-related mass emissions of PAHs and HPAHs were estimated based on measured emission factors. According to our results, PAHs and HPAHs emissions via particulate phase were greater than those via gaseous phase; particles in 2.1-3.3 μm size fraction, have the major contribution to particulate PAHs and HPAHs emissions. Over all, contribution of traffic-related emission of PAHs (only ∼3% of the total PAHs emission in China) is an overstated source of PAHs pollution in China. Actually, exhaust pipe emission contributed much less than the total traffic-related emission of pollutants. Copyright © 2018 Elsevier Ltd. All rights reserved.

Allometric scaling of UK urban emissions: interpretation and implications for air quality management

NASA Astrophysics Data System (ADS)

MacKenzie, Rob; Barnes, Matt; Whyatt, Duncan; Hewitt, Nick

2016-04-01

Allometry uncovers structures and patterns by relating the characteristics of complex systems to a measure of scale. We present an allometric analysis of air quality for UK urban settlements, beginning with emissions and moving on to consider air concentrations. We consider both airshed-average 'urban background' concentrations (cf. those derived from satellites for NO2) and local pollution 'hotspots'. We show that there is a strong and robust scaling (with respect to population) of the non-point-source emissions of the greenhouse gases carbon dioxide and methane, as well as the toxic pollutants nitrogen dioxide, PM2.5, and 1,3-butadiene. The scaling of traffic-related emissions is not simply a reflection of road length, but rather results from the socio-economic patterning of road-use. The recent controversy regarding diesel vehicle emissions is germane to our study but does not affect our overall conclusions. We next develop an hypothesis for the population-scaling of airshed-average air concentrations, with which we demonstrate that, although average air quality is expected to be worse in large urban centres compared to small urban centres, the overall effect is an economy of scale (i.e., large cities reduce the overall burden of emissions compared to the same population spread over many smaller urban settlements). Our hypothesis explains satellite-derived observations of airshed-average urban NO2 concentrations. The theory derived also explains which properties of nature-based solutions (urban greening) can make a significant contribution at city scale, and points to a hitherto unforeseen opportunity to make large cities cleaner than smaller cities in absolute terms with respect to their airshed-average pollutant concentration.

Source apportionment vs. emission inventories of non-methane hydrocarbons (NMHC) in an urban area of the Middle East: local and global perspectives

NASA Astrophysics Data System (ADS)

Salameh, Thérèse; Sauvage, Stéphane; Afif, Charbel; Borbon, Agnès; Locoge, Nadine

2016-03-01

We applied the positive matrix factorization model to two large data sets collected during two intensive measurement campaigns (summer 2011 and winter 2012) at a sub-urban site in Beirut, Lebanon, in order to identify NMHC (non-methane hydrocarbons) sources and quantify their contribution to ambient levels. Six factors were identified in winter and five factors in summer. PMF-resolved source profiles were consistent with source profiles established by near-field measurements. The major sources were traffic-related emissions (combustion and gasoline evaporation) in winter and in summer accounting for 51 and 74 wt %, respectively, in agreement with the national emission inventory. The gasoline evaporation related to traffic source had a significant contribution regardless of the season (22 wt % in winter and 30 wt % in summer). The NMHC emissions from road transport are estimated from observations and PMF results, and compared to local and global emission inventories. The PMF analysis finds reasonable differences on emission rates, of 20-39 % higher than the national road transport inventory. However, global inventories (ACCMIP, EDGAR, MACCity) underestimate the emissions up to a factor of 10 for the transportation sector. When combining emission inventory to our results, there is strong evidence that control measures in Lebanon should be targeted on mitigating the NMHC emissions from the traffic-related sources. From a global perspective, an assessment of VOC (volatile organic compounds) anthropogenic emission inventories for the Middle East region as a whole seems necessary as these emissions could be much higher than expected at least from the road transport sector.

Quantifying the linear and nonlinear relations between the urban form fragmentation and the carbon emission distribution

NASA Astrophysics Data System (ADS)

Zuo, S.; Dai, S.; Ren, Y.; Yu, Z.

2017-12-01

Scientifically revealing the spatial heterogeneity and the relationship between the fragmentation of urban landscape and the direct carbon emissions are of great significance to land management and urban planning. In fact, the linear and nonlinear effects among the various factors resulted in the carbon emission spatial map. However, there is lack of the studies on the direct and indirect relations between the carbon emission and the city functional spatial form changes, which could not be reflected by the land use change. The linear strength and direction of the single factor could be calculated through the correlation and Geographically Weighted Regression (GWR) analysis, the nonlinear power of one factor and the interaction power of each two factors could be quantified by the Geodetector analysis. Therefore, we compared the landscape fragmentation metrics of the urban land cover and functional district patches to characterize the landscape form and then revealed the relations between the landscape fragmentation level and the direct the carbon emissions based on the three methods. The results showed that fragmentation decreased and the fragmented patches clustered at the coarser resolution. The direct CO2 emission density and the population density increased when the fragmentation level aggregated. The correlation analysis indicated the weak linear relation between them. The spatial variation of GWR output indicated the fragmentation indicator (MESH) had the positive influence on the carbon emission located in the relatively high emission region, and the negative effects regions accounted for the small part of the area. The Geodetector which explores the nonlinear relation identified the DIVISION and MESH as the most powerful direct factor for the land cover patches, NP and PD for the functional district patches, and the interactions between fragmentation indicator (MESH) and urban sprawl metrics (PUA and DIS) had the greatly increased explanation powers on the urban carbon emission. Overall, this study provides a framework to understand the relation between the urban landscape fragmentation and the carbon emission for the low carbon city construction planning in the other cities.

[Emission Characteristics of Vehicle Exhaust in Beijing Based on Actual Traffic Flow Information].

PubMed

Fan, Shou-bin; Tian, Ling-di; Zhang, Dong-xu; Qu, Song

2015-08-01

The basic data of traffic volume, vehicle type constitute and speed on road networks in Beijing was obtained fly modei simulation and field survey. Based on actual traffic flow information and. emission factors data with temporal and spatial distribution features, emission inventory of motor vehicle exhaust in Beijing was built on the ArcGIS platform, meanwhile, the actual road emission characteristics and spatial distribution of the pollutant emissions were analyzed. The results showed that the proportion of passenger car was higher than 89% on each type of road in the urban, and the proportion of passenger car was the highest in suburban roads as well while the pickup truck, medium truck, heavy truck, motorbus, tractor and motorcycle also occupied a certain proportion. There was a positive correlation between the pollutant emission intensity and traffic volume, and the emission intensity was generally higher in daytime than nighttime, but the diurnal variation trend of PM emission was not clear for suburban roads and the emission intensity was higher in nighttime than daytime for highway. The emission intensities in urban area, south, southeast and northeast areas near urban were higher than those in the western and northern mountainous areas with lower density of road network. The ring roads in urban and highways in suburban had higher emission intensity because of the heavy traffic volume.

Impacts of urbanization on nitrogen deposition in the Pearl River Delta region, China

NASA Astrophysics Data System (ADS)

Wang, X.; Fan, Q.

2015-12-01

The Pearl River Delta (PRD) region is one of the most advanced economic districts in China, which has experienced remarkable economic development and urbanization in the past two decades. Accompanied with the rapid economy development and urbanization, the PRD region encountered both severe nitrogen pollution and deposition. In this study, the characteristics of nitrogen deposition and impacts of urbanization on nitrogen deposition in the PRD region were investigated by combining the methods of field study and numerical model. According to the field measurements, the total dry and wet atmospheric deposition of reactive N at a urban site (SYSU) was up to 55.0 kg ha-1 yr-1 in 2010, slightly lower than the results at a rural forest site (DHS) (57.6 kg ha-1 yr-1). Wet deposition was the main form of the total deposition (64-76%). Organic nitrogen (ON) was found to be dominant in the total N deposition, with a contribution of 53% at DHS and 42% at SYSU. NH4+-N and NO3--N accounted for a similar portion of the total N deposition (23-29%). Atmospheric nitrogen deposition was further simulated by using the improved WRF-Chem model. The simulated N deposition flux was high in the north of PRD (i.e., Guangzhou, Foshan, Zhaoqing) and relative low in the east (Huizhou) and south (Zhuhai), with an average N deposition flux of about 24 kg ha-1 yr-1 for the whole PRD. The distribution of N dry deposition was mainly controlled by the concentration of reactive N compounds and precipitation governed the wet deposition distribution. The modeling results also indicate that the PRD area is the source region in which the emissions exceed the deposition while the outside area of the PRD is the receptor region in which the deposition exceeds emissions. The impact of emission change and land use change due to urbanization was also investigated using the WRF-Chem model. The results showed that atmospheric N deposition exhibits a direct response to emission change while the land use change impacts the atmospheric N deposition indirectly mainly through the modification of precipitation. As a result of great challenges in reduction of the reactive N emission, a scenario of rising N deposition in the PRD cannot be discarded in the future.

Attribution of nitrogen deposition driven by urbanization over Pearl River Delta region China

NASA Astrophysics Data System (ADS)

Wang, X.; Wu, Z.

2016-12-01

The Pearl River Delta (PRD) region is one of the most advanced economic districts in China, which has experienced remarkable economic development and urbanization in the past two decades. Accompanied with the rapid economy development and urbanization, the PRD region encountered both severe nitrogen pollution and deposition. In this study, the characteristics of nitrogen deposition and impacts of urbanization on nitrogen deposition in the PRD region were investigated by combining the methods of field study and numerical model. According to the field measurements, the total dry and wet atmospheric deposition of reactive N at a urban site (SYSU) was up to 55.0 kg ha-1 yr-1 in 2010, slightly lower than the results at a rural forest site (DHS) (57.6 kg ha-1 yr-1). Wet deposition was the main form of the total deposition (64-76%). Organic nitrogen (ON) was found to be dominant in the total N deposition, with a contribution of 53% at DHS and 42% at SYSU. NH4+-N and NO3-N accounted for a similar portion of the total N deposition (23-29%). Atmospheric nitrogen deposition was further simulated by using the improved WRF-Chem model. The simulated N deposition flux was high in the north of PRD (i.e.,Guangzhou, Foshan, Zhaoqing) and relative low in the east (Huizhou) and south (Zhuhai), with an average N deposition flux of about 24 kg ha-1 yr-1 for the whole PRD. The distribution of N dry deposition was mainly controlled by the concentration of reactive N compounds and precipitation governed the wet deposition distribution. The modeling results also indicate that the PRD area is the source region in which the emissions exceed the deposition while the outside area of the PRD is the receptor region in which the deposition exceeds emissions. The impact of emission change and land use change due to urbanization was also investigated using the WRF-Chem model. The results showed that atmospheric N deposition exhibits a direct response to emission change while the land use change impacts the atmospheric N deposition indirectly mainly through the modification of precipitation. As a result of great challenges in reduction of the reactive N emission, a scenario of rising N deposition in the PRD cannot be discarded in the future.

Exploring the roles of temperature and NOx on ozone production in the Sacramento urban plume

NASA Astrophysics Data System (ADS)

Lafranchi, B. W.; Cohen, R. C.

2009-12-01

We investigate the role of temperature and NOx (NOx = NO+NO2) on ozone (O3) production in the Sacramento urban plume over a stretch of seven years (2001-2007) using data collected at UC Blodgett Forest Research Station (a forested site in the Sierra Nevadas about 80 km downwind of Sacramento, CA) and at a series of California Air Resources Board (CARB) sites along the Sacramento-Blodgett transect. The consistent daytime wind patterns between the Central Valley of California and the foothills of the Sierra Nevada mountains permits the assumption of plume transport from downtown Sacramento, over the CARB monitoring sites in the eastern suburbs, and past the Blodgett Forest research site. While NOx emissions are limited primarily to the urban and suburban regions of the transect, biogenic volatile organic compound (VOC) emissions are significant throughout the transect, thus there is a fast transition from VOC-limited to NOx-limited as the plume travels away from the urban center, and we have the opportunity to analyze the differences in ozone production across these two chemical regimes. For this analysis, the Sacramento-Blodgett transect is separated into three segments: urban, suburban, and rural, defined by the locations of selected monitoring sites. Ozone concentrations across each segment are controlled by chemical production (Pchem) and loss (Lchem), deposition to surfaces (Ldep), and mixing with background air (Lmix). At an assumed deposition rate, mixing rate, and background O3 concentration, the net chemical flux of ozone (Pchem - Lchem) can be inferred from differences in ozone concentrations between adjacent monitoring sites. We show that ozone production rates, in general, increase with temperature. We also show that decreases in NOx emissions over the period from 2001-2007 have been effective at reducing ozone production at all points along the transect, but only on days where temperatures are highest. At low temperatures, this decrease is less apparent, and in the urban transect, ozone production is observed to increase as NOx concentrations decrease. This is attributed to the high NOx/VOC ratio that results from reduced biogenic emissions and strong local inputs of NOx, thus driving the chemical environment into a NOx-saturated regime. From these results, we give predictions of future ozone exceedences for various emissions and climate scenarios.

High Resolution Atmospheric Inversion of Urban CO2 Emissions During the Dormant Season of the Indianapolis Flux Experiment (INFLUX)

NASA Technical Reports Server (NTRS)

Lauvaux, Thomas; Miles, Natasha L.; Deng, Aijun; Richardson, Scott J.; Cambaliza, Maria O.; Davis, Kenneth J.; Gaudet, Brian; Gurney, Kevin R.; Huang, Jianhua; O'Keefe, Darragh;

Evaluation of diesel fleet emissions and control policies from plume chasing measurements of on-road vehicles

NASA Astrophysics Data System (ADS)

Lau, Chui Fong; Rakowska, Agata; Townsend, Thomas; Brimblecombe, Peter; Chan, Tat Leung; Yam, Yat Shing; Močnik, Griša; Ning, Zhi

2015-12-01

Vehicle emissions are an important source of urban air pollution. Diesel fuelled vehicles, although constituting a relatively small fraction of fleet population in many cities, are significant contributors to the emission inventory due to their often long mileage for goods and public transport. Recent classification of diesel exhaust as carcinogenic by the World Health Organization also raises attention to more stringent control of diesel emissions to protect public health. Although various mandatory and voluntary based emission control measures have been implemented in Hong Kong, there have been few investigations to evaluate if the fleet emission characteristics have met desired emission reduction objectives and if adoption of an Inspection/Maintenance (I/M) programme has been effective in achieving these objectives. The limitations are partially due to the lack of cost-effective approaches for the large scale characterisation of fleet based emissions to assess the effectiveness of control measures and policy. This study has used a plume chasing method to collect a large amount of on-road vehicle emission data of Hong Kong highways and a detailed analysis was carried out to provide a quantitative evaluation of the emission characteristics in terms of the role of high and super-emitters in total emission reduction, impact of after-treatment on the multi-pollutants reduction strategy and the trend of NO2 emissions with newer emission standards. The study revealed that not all the high-emitters are from those vehicles of older Euro emission standards. Meanwhile, there is clear evidence that high-emitters for one pollutant may not be a high-emitter for another pollutant. Multi-pollutant control strategy needs to be considered in the enactment of the emission control policy which requires more comprehensive retrofitting technological solutions and matching I/M programme to ensure the proper maintenance of fleets. The plume chasing approach used in this study also shows to be a useful approach for assessing city wide vehicle emission characteristics.

PRELIMINARY ANALYSIS OF HAZARDOUS AIR POLLUTANT EMISSION INVENTORIES FROM THREE MAJOR URBAN AREAS

EPA Science Inventory

The paper reports EPA/AEERL's progress on emissions inventory evaluation and improvement under a hazardous air pollutant (HAP) emissions research program in support of the Urban Area Source Program required under Title III of the Clean Air Act Amendments of 1990 (CAAA). he paper ...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Couth, R.; Trois, C., E-mail: troisc@ukzn.ac.za

Highlights: Black-Right-Pointing-Pointer The financial/social/institutional sustainability of waste management in Africa is analysed. Black-Right-Pointing-Pointer This note is a compendium of a study on the potential for GHG control via improved zero waste in Africa. Black-Right-Pointing-Pointer This study provides the framework for Local Authorities for realizing sustained GHG reductions. - Abstract: Greenhouse gas (GHG) emissions per person from urban waste management activities are greater in sub-Saharan African countries than in other developing countries, and are increasing as the population becomes more urbanised. Waste from urban areas across Africa is essentially dumped on the ground and there is little control over the resultingmore » gas emissions. The clean development mechanism (CDM), from the 1997 Kyoto Protocol has been the vehicle to initiate projects to control GHG emissions in Africa. However, very few of these projects have been implemented and properly registered. A much more efficient and cost effective way to control GHG emissions from waste is to stabilise the waste via composting and to use the composted material as a soil improver/organic fertiliser or as a component of growing media. Compost can be produced by open windrow or in-vessel composting plants. This paper shows that passively aerated open windrows constitute an appropriate low-cost option for African countries. However, to provide an usable compost material it is recommended that waste is processed through a materials recovery facility (MRF) before being composted. The paper demonstrates that material and biological treatment (MBT) are viable in Africa where they are funded, e.g. CDM. However, they are unlikely to be instigated unless there is a replacement to the Kyoto Protocol, which ceases for Registration in December 2012.« less

Cities’ Role in Mitigating United States Food System Greenhouse Gas Emissions

PubMed Central

2018-01-01

Current trends of urbanization, population growth, and economic development have made cities a focal point for mitigating global greenhouse gas (GHG) emissions. The substantial contribution of food consumption to climate change necessitates urban action to reduce the carbon intensity of the food system. While food system GHG mitigation strategies often focus on production, we argue that urban influence dominates this sector’s emissions and that consumers in cities must be the primary drivers of mitigation. We quantify life cycle GHG emissions of the United States food system through data collected from literature and government sources producing an estimated total of 3800 kg CO2e/capita in 2010, with cities directly influencing approximately two-thirds of food sector GHG emissions. We then assess the potential for cities to reduce emissions through selected measures; examples include up-scaling urban agriculture and home delivery of grocery options, which each may achieve emissions reductions on the order of 0.4 and ∼1% of this total, respectively. Meanwhile, changes in waste management practices and reduction of postdistribution food waste by 50% reduce total food sector emissions by 5 and 11%, respectively. Consideration of the scale of benefits achievable through policy goals can enable cities to formulate strategies that will assist in achieving deep long-term GHG emissions targets. PMID:29717606

Cities' Role in Mitigating United States Food System Greenhouse Gas Emissions.

PubMed

Mohareb, Eugene A; Heller, Martin C; Guthrie, Peter M

2018-05-15

Current trends of urbanization, population growth, and economic development have made cities a focal point for mitigating global greenhouse gas (GHG) emissions. The substantial contribution of food consumption to climate change necessitates urban action to reduce the carbon intensity of the food system. While food system GHG mitigation strategies often focus on production, we argue that urban influence dominates this sector's emissions and that consumers in cities must be the primary drivers of mitigation. We quantify life cycle GHG emissions of the United States food system through data collected from literature and government sources producing an estimated total of 3800 kg CO 2 e/capita in 2010, with cities directly influencing approximately two-thirds of food sector GHG emissions. We then assess the potential for cities to reduce emissions through selected measures; examples include up-scaling urban agriculture and home delivery of grocery options, which each may achieve emissions reductions on the order of 0.4 and ∼1% of this total, respectively. Meanwhile, changes in waste management practices and reduction of postdistribution food waste by 50% reduce total food sector emissions by 5 and 11%, respectively. Consideration of the scale of benefits achievable through policy goals can enable cities to formulate strategies that will assist in achieving deep long-term GHG emissions targets.

Urban energy consumption and related carbon emission estimation: a study at the sector scale

NASA Astrophysics Data System (ADS)

Lu, Weiwei; Chen, Chen; Su, Meirong; Chen, Bin; Cai, Yanpeng; Xing, Tao

2013-12-01

With rapid economic development and energy consumption growth, China has become the largest energy consumer in the world. Impelled by extensive international concern, there is an urgent need to analyze the characteristics of energy consumption and related carbon emission, with the objective of saving energy, reducing carbon emission, and lessening environmental impact. Focusing on urban ecosystems, the biggest energy consumer, a method for estimating energy consumption and related carbon emission was established at the urban sector scale in this paper. Based on data for 1996-2010, the proposed method was applied to Beijing in a case study to analyze the consumption of different energy resources (i.e., coal, oil, gas, and electricity) and related carbon emission in different sectors (i.e., agriculture, industry, construction, transportation, household, and service sectors). The results showed that coal and oil contributed most to energy consumption and carbon emission among different energy resources during the study period, while the industrial sector consumed the most energy and emitted the most carbon among different sectors. Suggestions were put forward for energy conservation and emission reduction in Beijing. The analysis of energy consumption and related carbon emission at the sector scale is helpful for practical energy saving and emission reduction in urban ecosystems.

76 FR 15308 - Completion of the Requirement To Promulgate Emission Standards

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-21

... CONTACT: Mr. Nathan Topham, Sector Policies and Programs Division, Office of Air Quality Planning and... the aggregate area source emissions of each of the 30 urban hazardous air pollutants (HAP) are subject... list of the 30 urban HAP, please see National Air Toxics Program: The Integrate Urban Strategy, 64 FR...

Air Pollution Prevention and Control Policy in China.

PubMed

Huang, Cunrui; Wang, Qiong; Wang, Suhan; Ren, Meng; Ma, Rui; He, Yiling

2017-01-01

With rapid urbanization and development of transport infrastructure, air pollution caused by multiple-pollutant emissions and vehicle exhaust has been aggravated year by year in China. In order to improve air quality, the Chinese authorities have taken a series of actions to control air pollution emission load within a permissible range. However, although China has made positive progress on tackling air pollution, these actions have not kept up with its economy growth and fossil-fuel use. The traditional single-pollutant approach is far from enough in China now, and in the near future, air pollution control strategies should move in the direction of the multiple-pollutant approach. In addition, undesirable air quality is usually linked with the combination of high emissions and adverse weather conditions. However, few studies have been done on the influence of climate change on atmospheric chemistry in the global perspective. Available evidence suggested that climate change is likely to exacerbate certain kinds of air pollutants including ozone and smoke from wildfires. This has become a major public health problem because the interactions of global climate change, urban heat islands, and air pollution have adverse effects on human health. In this chapter, we first review the past and current circumstances of China's responses to air pollution. Then we discuss the control challenges and future options for a better air quality in China. Finally, we begin to unravel links between air pollution and climate change, providing new opportunities for integrated research and actions in China.

Experimental modeling of NOx and PM generation from combustion of various biodiesel blends for urban transport buses : research brief.

DOT National Transportation Integrated Search

2016-08-01

Although it is generally accepted : that biodiesel fuel contributes : to the reduction of pollutants, : biodiesel still needs more study : for better control of combustion emissions and engine performance. Biodiesel has very diverse : sources of feed...

Synegies Between Visible/Near-Infrared Imaging Spectrometry and the Thermal Infrared in an Urban Environment: An Evaluation of the Hyperspectral Infrared Imager (HYSPIRI) Mission

NASA Technical Reports Server (NTRS)

Roberts, Dar A.; Quattrochi, Dale A.; Hulley, Glynn C.; Hook, Simon J.; Green, Robert O.

2012-01-01

A majority of the human population lives in urban areas and as such, the quality of urban environments is becoming increasingly important to the human population. Furthermore, these areas are major sources of environmental contaminants and sinks of energy and materials. Remote sensing provides an improved understanding of urban areas and their impacts by mapping urban extent, urban composition (vegetation and impervious cover fractions), and urban radiation balance through measures of albedo, emissivity and land surface temperature (LST). Recently, the National Research Council (NRC) completed an assessment of remote sensing needs for the next decade (NRC, 2007), proposing several missions suitable for urban studies, including a visible, near-infrared and shortwave infrared (VSWIR) imaging spectrometer and a multispectral thermal infrared (TIR) instrument called the Hyperspectral Infrared Imagery (HyspIRI). In this talk, we introduce the HyspIRI mission, focusing on potential synergies between VSWIR and TIR data in an urban area. We evaluate potential synergies using an Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) and MODIS-ASTER (MASTER) image pair acquired over Santa Barbara, United States. AVIRIS data were analyzed at their native spatial resolutions (7.5m VSWIR and 15m TIR), and aggregated 60 m spatial resolution similar to HyspIRI. Surface reflectance was calculated using ACORN and a ground reflectance target to remove atmospheric and sensor artifacts. MASTER data were processed to generate estimates of spectral emissivity and LST using Modtran radiative transfer code and the ASTER Temperature Emissivity Separation algorithm. A spectral library of common urban materials, including urban vegetation, roofs and roads was assembled from combined AVIRIS and field-measured reflectance spectra. LST and emissivity were also retrieved from MASTER and reflectance/emissivity spectra for a subset of urban materials were retrieved from co-located MASTER and AVIRIS pixels. Fractions of Impervious, Soil, Green Vegetation (GV) and Non-photosynthetic Vegetation (NPV), were estimated using Multiple Endmember Spectral Mixture Analysis (MESMA) applied to AVIRIS data at 7.5, 15 and 60 m spatial scales. Surface energy parameters, including albedo, vegetation cover fraction, broadband emissivity and LST were also determined for urban and natural land-cover classes in the region. Fractions were validated using 1m digital photography.

NOx emission trends over Chinese cities estimated from OMI observations during 2005 to 2015.

PubMed

Liu, Fei; Beirle, Steffen; Zhang, Qiang; van der A, Ronald J; Zheng, Bo; Tong, Dan; He, Kebin

2017-01-01

Satellite NO 2 observations have been widely used to evaluate emission changes. To determine trends in NO x emission over China, we used a method independent of chemical transport models to quantify the NO x emissions from 48 cities and 7 power plants over China, on the basis of Ozone Monitoring Instrument (OMI) NO 2 observations during 2005 to 2015. We found that NO x emissions over 48 Chinese cities increased by 52% from 2005 to 2011 and decreased by 21% from 2011 to 2015. The decrease since 2011 could be mainly attributed to emission control measures in power sector; while cities with different dominant emission sources (i.e. power, industrial and transportation sectors) showed variable emission decline timelines that corresponded to the schedules for emission control in different sectors. The time series of the derived NO x emissions was consistent with the bottom-up emission inventories for all power plants (r=0.8 on average), but not for some cities (r=0.4 on average). The lack of consistency observed for cities was most probably due to the high uncertainty of bottom-up urban emissions used in this study, which were derived from downscaling the regional-based emission data to cities by using spatial distribution proxies.

NOx emission trends over Chinese cities estimated from OMI observations during 2005 to 2015

NASA Astrophysics Data System (ADS)

Liu, Fei; Beirle, Steffen; Zhang, Qiang; van der A, Ronald J.; Zheng, Bo; Tong, Dan; He, Kebin

2017-08-01

Satellite nitrogen dioxide (NO2) observations have been widely used to evaluate emission changes. To determine trends in nitrogen oxides (NOx) emission over China, we used a method independent of chemical transport models to quantify the NOx emissions from 48 cities and seven power plants over China, on the basis of Ozone Monitoring Instrument (OMI) NO2 observations from 2005 to 2015. We found that NOx emissions over 48 Chinese cities increased by 52 % from 2005 to 2011 and decreased by 21 % from 2011 to 2015. The decrease since 2011 could be mainly attributed to emission control measures in power sector; while cities with different dominant emission sources (i.e., power, industrial, and transportation sectors) showed variable emission decline timelines that corresponded to the schedules for emission control in different sectors. The time series of the derived NOx emissions was consistent with the bottom-up emission inventories for all power plants (r = 0. 8 on average), but not for some cities (r = 0. 4 on average). The lack of consistency observed for cities was most probably due to the high uncertainty of bottom-up urban emissions used in this study, which were derived from downscaling the regional-based emission data to city level by using spatial distribution proxies.

Effects of Land Cover Change on Soil Greenhouse Gas Fluxes in Subtropical Hong Kong

NASA Astrophysics Data System (ADS)

Wong, C. N.; Lai, D. Y. F.

2016-12-01

Nowadays, over 50% of the world's population live in urbanized areas and the level of urbanization varies substantially across countries. Intense human activities and management associated with urbanization can alter the microclimate and biochemical processes in urban areas, which subsequently affect the provision of ecosystem services and functions. Soil greenhouse gas (GHG) exchange plays an important role in governing future climate change. Yet, the effects of urbanization on soil GHG exchange remain uncertain and not well understood. This study aims to examine the effects of urbanization on GHG fluxes among four land covers- natural forest, urban forest, farmland and roadside planter in Hong Kong based on closed chamber measurements for one full year. CO2 emission significantly varied among land covers (p<0.05), with the highest and lowest CO2 emissions being recorded in roadside planter and farmland, respectively. The N2O flux was highest in roadside planter whereas the lowest flux was recorded in urban forest, though the difference in N2O fluxes was only statistically significant at a level of 0.1. No significant difference of CH4 emission was found among all the land covers. Emission of CO2 increased markedly with soil organic matter content, while N2O flux increased markedly with total Kjeldahl nitrogen content. The results obtained in this study will enhance our understanding on urban ecosystem and be useful for recommending sustainable management strategies for conservation of ecosystem services in urban areas.

Empirical Research on Decoupling Relationship between Energy-Related Carbon Emission and Economic Growth in Guangdong Province Based on Extended Kaya Identity

PubMed Central

Wang, Wenxiu; Huang, Ningsheng; Zhao, Daiqing

2014-01-01

The decoupling elasticity decomposition quantitative model of energy-related carbon emission in Guangdong is established based on the extended Kaya identity and Tapio decoupling model for the first time, to explore the decoupling relationship and its internal mechanism between energy-related carbon emission and economic growth in Guangdong. Main results are as follows. (1) Total production energy-related carbon emissions in Guangdong increase from 4128 × 104 tC in 1995 to 14396 × 104 tC in 2011. Decoupling elasticity values of energy-related carbon emission and economic growth increase from 0.53 in 1996 to 0.85 in 2011, and its decoupling state turns from weak decoupling in 1996–2004 to expansive coupling in 2005–2011. (2) Land economic output and energy intensity are the first inhibiting factor and the first promoting factor to energy-related carbon emission decoupling from economic growth, respectively. The development speeds of land urbanization and population urbanization, especially land urbanization, play decisive roles in the change of total decoupling elasticity values. (3) Guangdong can realize decoupling of energy-related carbon emission from economic growth effectively by adjusting the energy mix and industrial structure, coordinating the development speed of land urbanization and population urbanization effectively, and strengthening the construction of carbon sink. PMID:24782666

Empirical research on decoupling relationship between energy-related carbon emission and economic growth in Guangdong province based on extended Kaya identity.

PubMed

Wang, Wenxiu; Kuang, Yaoqiu; Huang, Ningsheng; Zhao, Daiqing

2014-01-01

The decoupling elasticity decomposition quantitative model of energy-related carbon emission in Guangdong is established based on the extended Kaya identity and Tapio decoupling model for the first time, to explore the decoupling relationship and its internal mechanism between energy-related carbon emission and economic growth in Guangdong. Main results are as follows. (1) Total production energy-related carbon emissions in Guangdong increase from 4128 × 10⁴ tC in 1995 to 14396 × 10⁴ tC in 2011. Decoupling elasticity values of energy-related carbon emission and economic growth increase from 0.53 in 1996 to 0.85 in 2011, and its decoupling state turns from weak decoupling in 1996-2004 to expansive coupling in 2005-2011. (2) Land economic output and energy intensity are the first inhibiting factor and the first promoting factor to energy-related carbon emission decoupling from economic growth, respectively. The development speeds of land urbanization and population urbanization, especially land urbanization, play decisive roles in the change of total decoupling elasticity values. (3) Guangdong can realize decoupling of energy-related carbon emission from economic growth effectively by adjusting the energy mix and industrial structure, coordinating the development speed of land urbanization and population urbanization effectively, and strengthening the construction of carbon sink.

Tracking urban carbon footprints from production and consumption perspectives

NASA Astrophysics Data System (ADS)

Lin, Jianyi; Hu, Yuanchao; Cui, Shenghui; Kang, Jiefeng; Ramaswami, Anu

2015-05-01

Cities are hotspots of socio-economic activities and greenhouse gas emissions. The aim of this study was to extend the research range of the urban carbon footprint (CF) to cover emissions embodied in products traded among regions and intra-city sectors. Using Xiamen City as a study case, the total urban-related emissions were evaluated, and the carbon flows among regions and intra-city sectors were tracked. Then five urban CF accountings were evaluated, including purely geographic accounting (PGA), community-wide infrastructure footprint (CIF), and consumption-based footprint (CBF) methods, as well as the newly defined production-based footprint (PBF) and purely production footprint (PPF). Research results show that the total urban-related emissions of Xiamen City in 2010 were 55.2 Mt CO2e/y, of which total carbon flow among regions or intra-city sectors accounted for 53.7 Mt CO2e/y. Within the total carbon flow, import and export respectively accounted for 59 and 65%, highlighting the importance of emissions embodied in trade. By regional trade balance, North America and Europe were the largest net carbon exported-to regions, and Mainland China and Taiwan the largest net carbon imported-from regions. Among intra-sector carbon flows, manufacturing was the largest emission-consuming sector of the total urban carbon flow, accounting for 77.4, and 98% of carbon export was through industrial products trade. By the PBF, PPF, CIF, PGA and CBF methods, the urban CFs were respectively 53.7 Mt CO2e/y, 44.8 Mt CO2e/y, 28.4 Mt CO2e/y, 23.7 Mt CO2e/y, and 19.0 Mt CO2e/y, so all of the other four CFs were higher than the CBF. All of these results indicate that urban carbon mitigation must consider the supply chain management of imported goods, the production efficiency within the city, the consumption patterns of urban consumers, and the responsibility of the ultimate consumers outside the city.

Estimates of ozone response to various combinations of NO(x) and VOC emission reductions in the eastern United States

NASA Technical Reports Server (NTRS)

Roselle, Shawn J.; Schere, Kenneth L.; Chu, Shao-Hang

1994-01-01

There is increasing recognition that controls on NO(x) emissions may be necessary, in addition to existing and future Volatile Organic Compounds (VOC) controls, for the abatement of ozone (O3) over portions of the United States. This study compares various combinations of anthropogenic NO(x) and VOC emission reductions through a series of model simulations. A total of 6 simulations were performed with the Regional Oxidant Model (ROM) for a 9-day period in July 1988. Each simulation reduced anthropogenic NO(x) and VOC emissions across-the-board by different amounts. Maximum O3 concentrations for the period were compared between the simulations. Comparison of the simulations suggests that: (1) NO(x) controls may be more effective than VOC controls in reducing peak O3 over most of the eastern United States; (2) VOC controls are most effective in urban areas having large sources of emissions; (3) NO(x) controls may increase O3 near large point sources; and (4) the benefit gained from increasing the amount of VOC controls may lessen as the amount of NO(x) control is increased. This paper has been reviewed in accordance with the U.S. Environmental Protection Agency's peer and administrative review policies and approved for presentation and publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use.

Report card on low level ozone in urban areas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Onischak, M.

1994-12-31

It has been four years since the Clean Air Act was amended in November of 1990. Much work has been done in this time, and the country is beginning to see real air quality benefits. Although these changes have not completely licked the urban ozone problem yet, they have made a lot of progress. All of the urban areas which have been required to reduce their ozone levels have done a good job of lowering their emissions. While the urban areas have not all been able to meet every federal deadline, the areas have all been able to achieve themore » control milestones before the mandatory Clean Air Act sanctions have taken effect. Some areas are even ready to declare their ozone problems solved.« less

[Synergistic emission reduction of chief air pollutants and greenhouse gases-based on scenario simulations of energy consumptions in Beijing].

PubMed

Xie, Yuan-bo; Li, Wei

2013-05-01

It is one of the common targets and important tasks for energy management and environmental control of Beijing to improve urban air quality while reducing the emissions of greenhouse gases (GHG). Here, based on the interim and long term developmental planning and energy structure of the city, three energy consumption scenarios in low, moderate and high restrictions were designed by taking the potential energy saving policies and environmental targets into account. The long-range energy alternatives planning (LEAP) model was employed to predict and evaluate reduction effects of the chief air pollutants and GHG during 2010 to 2020 under the three given scenarios. The results showed that if urban energy consumption system was optimized or adjusted by exercising energy saving and emission reduction and pollution control measures, the predicted energy uses will be reduced by 10 to 30 million tons of coal equivalents by 2020. Under the two energy scenarios with moderate and high restrictions, the anticipated emissions of SO2, NOx, PM10, PM2.5, VOC and GHG will be respectively reduced to 71 to 100.2, 159.2 to 218.7, 89.8 to 133.8, 51.4 to 96.0, 56.4 to 74.8 and 148 200 to 164 700 thousand tons. Correspondingly, when compared with the low-restriction scenario, the reducing rate will be 53% to 67% , 50% to 64% , 33% to 55% , 25% to 60% , 41% to 55% and 26% to 34% respectively. Furthermore, based on a study of synergistic emission reduction of the air pollutants and GHG, it was proposed that the adjustment and control of energy consumptions shall be intensively developed in the three sectors of industry, transportation and services. In this way the synergistic reduction of the emissions of chief air pollutants and GHG will be achieved; meanwhile the pressures of energy demands may be deliberately relieved.

Characteristics of atmospheric ammonia and its relationship with vehicle emissions in a megacity in China

NASA Astrophysics Data System (ADS)

Wang, Ruyu; Ye, Xingnan; Liu, Yuxuan; Li, Haowen; Yang, Xin; Chen, Jianmin; Gao, Wei; Yin, Zi

2018-06-01

Atmospheric ammonia plays an important role in haze formation in East China. In this study, long-term measurements of NH3 concentrations were implemented at urban, suburban, and tunnel sites in Shanghai, the largest city in East China. The average monthly ammonia concentrations at the urban site varied from 3.7 ppb to 14.5 ppb and exhibited the highest levels in summer and lowest levels in winter, indicating that the biological emissions and agriculture in the surrounding areas are important contributors. The suburban NH3 levels were significantly higher in autumn compared to those at the urban site, indicating the important contribution of agricultural activities. Regardless of the season, the difference of NH3 concentrations between the tunnel and urban sites remained almost constant. On average, the tunnel NH3 level was three times higher than that of the nearby urban site, indicating strong vehicle NH3 emissions in the tunnel. The tunnel NH3 levels on weekdays were comparable to those on weekends, a result that was in agreement with the daily average traffic volume. It was estimated that the vehicle emissions contributed 12.6-24.6% of the atmospheric NH3 in the urban area and 3.8-7.5% for the whole area of Shanghai. Our results suggest that vehicle NH3 emissions should be considered, although agricultural emissions are still more important for mitigating severe haze pollution during wintertime in the megacities of China.

Physical properties of particulate matter (PM) from late model heavy-duty diesel vehicles operating with advanced PM and NO x emission control technologies

NASA Astrophysics Data System (ADS)

Biswas, Subhasis; Hu, Shaohua; Verma, Vishal; Herner, Jorn D.; Robertson, William H.; Ayala, Alberto; Sioutas, Constantinos

Emission control technologies designed to meet the 2007 and 2010 emission standards for heavy-duty diesel vehicles (HDDV) remove effectively the non-volatile fraction of particles, but are comparatively less efficient at controlling the semi-volatile components. A collaborative study between the California Air Resources Board (CARB) and the University of Southern California was initiated to investigate the physicochemical and toxicological characteristics of the semi-volatile and non-volatile particulate matter (PM) fractions from HDDV emissions. This paper reports the physical properties, including size distribution, volatility (in terms of number and mass), surface diameter, and agglomeration of particles emitted from HDDV retrofitted with advanced emission control devices. Four vehicles in combination with six after-treatment devices (V-SCRT ®, Z-SCRT ®, CRT ®, DPX, Hybrid-CCRT ®, EPF) were tested under three driving cycles: steady state (cruise), transient (urban dynamometer driving schedule, UDDS), and idle. An HDDV without any control device is served as the baseline vehicle. Substantial reduction of PM mass emissions (>90%) was accomplished for the HDDV operating with advanced emission control technologies. This reduction was not observed for particle number concentrations under cruise conditions, with the exceptions of the Hybrid-CCRT ® and EPF vehicles, which were efficient in controlling both—mass and number emissions. In general, significant nucleation mode particles (<50 nm) were formed during cruise cycles in comparison with the UDDS cycles, which emit higher PM mass in the accumulation mode. The nucleation mode particles (<50 nm) were mainly internally mixed, and evaporated considerably between 150 and 230 °C. Compared to the baseline vehicle, particles from vehicles with controls (except of the Hybrid-CCRT ®) had a higher mass specific surface area.

The effect of urbanization and industrialization on carbon emissions in Turkey: evidence from ARDL bounds testing procedure.

PubMed

Pata, Ugur Korkut

2018-03-01

This paper examines the dynamic short- and long-term relationship between per capita GDP, per capita energy consumption, financial development, urbanization, industrialization, and per capita carbon dioxide (CO 2 ) emissions within the framework of the environmental Kuznets curve (EKC) hypothesis for Turkey covering the period from 1974 to 2013. According to the results of the autoregressive distributed lag bounds testing approach, an increase in per capita GDP, per capita energy consumption, financial development, urbanization, and industrialization has a positive effect on per capita CO 2 emissions in the long term, and also the variables other than urbanization increase per capita CO 2 emissions in the short term. In addition, the findings support the validity of the EKC hypothesis for Turkey in the short and long term. However, the turning points obtained from long-term regressions lie outside the sample period. Therefore, as the per capita GDP increases in Turkey, per capita CO 2 emissions continue to increase.

Tracing geogenic and anthropogenic sources in urban dusts: Insights from lead isotopes

NASA Astrophysics Data System (ADS)

Del Rio-Salas, R.; Ruiz, J.; De la O-Villanueva, M.; Valencia-Moreno, M.; Moreno-Rodríguez, V.; Gómez-Alvarez, A.; Grijalva, T.; Mendivil, H.; Paz-Moreno, F.; Meza-Figueroa, D.

2012-12-01

Tracing the source of metals in the environment is critical to understanding their pollution level and fate. Geologic materials are an important source of airborne particulate matter, but the contribution of contaminated soil to concentrations of Pb in airborne dust is not yet widely documented. To examine the potential significance of this mechanism, surface soil samples were collected, as well as wind-transported dust trapped at 1 and 2 m height at seven different locations including residential, industrial, high-traffic and rural sites. Samples of dust deposited on roofs from 24 schools were also obtained and analyzed for Pb isotope ratios. Spatial distribution of Pb of airborne and sedimented dust suggests a process dominated by re-suspension/sedimentation, which was controlled by erosion, traffic and topography of the urban area. Anthropogenic lead input in the city grades outward the urban zone toward geogenic values. Our results shows that Pb-isotopic signatures of leaded gasoline are imprinted in dust sedimented on roofs. Considering that leaded-gasoline has not been in use in Mexico since two decades ago, this signature shows not only a Pb-legacy in soil, but also a re-suspension process affecting air column below 3 m in height. The combination of the 207Pb/206Pb data of the surrounding rocks and urban dust, reveal three well-defined zones with remarkable anthropogenic influence, which correspond to the oldest urban sectors. This work highlights the importance of spatial characterization of metals in particles suspended below a height of 3 m of the airborne column, a fact that should be considered to identify exposure paths to humans and the potential risks. Lead isotope signatures allowed the identification of geogenic and anthropogenic emission sources for dust, a matter that deserves consideration in the efforts to control airborne metal emissions.

Mitigation of methane emissions in cities: How new measurements and partnerships can contribute to emissions reduction strategies

DOE PAGES

Hopkins, Francesca M.; Ehleringer, James R.; Bush, Susan E.; ...

2016-09-10

Cities generate 70% of anthropogenic greenhouse gas emissions, a fraction that is grow-ing with global urbanization. While cities play an important role in climate change mitigation, there has been little focus on reducing urban methane (CH4) emissions. Here, we develop a conceptual framework for CH 4 mitigation in cities by describing emission processes, the role of measurements, and a need for new institutional partnerships. Urban CH 4 emissions are likely to grow with expanding use of natural gas and organic waste disposal systems in growing population centers; however, we currently lack the ability to quantify this increase. We also lackmore » systematic knowledge of the relative contribution of these distinct source sectors on emissions. We present new observations from four North American cities to demonstrate that CH4 emissions vary in magnitude and sector from city to city and hence require different mitigation strategies. Detections of fugitive emissions from these systems suggest that current mitiga- tion approaches are absent or ineffective. These findings illustrate that tackling urban CH 4 emissions will require research efforts to identify mitigation targets, develop and implement new mitigation strategies, and monitor atmospheric CH 4 levels to ensure the success of mitigation efforts. This research will require a variety of techniques to achieve these objectives and should be deployed in cities globally. In conclusion, we suggest that metropolitan scale partnerships may effectively coordinate systematic measurements and actions focused on emission reduction goals.« less

Mitigation of methane emissions in cities: How new measurements and partnerships can contribute to emissions reduction strategies

NASA Astrophysics Data System (ADS)

Hopkins, Francesca M.; Ehleringer, James R.; Bush, Susan E.; Duren, Riley M.; Miller, Charles E.; Lai, Chun-Ta; Hsu, Ying-Kuang; Carranza, Valerie; Randerson, James T.

2016-09-01

Cities generate 70% of anthropogenic greenhouse gas emissions, a fraction that is growing with global urbanization. While cities play an important role in climate change mitigation, there has been little focus on reducing urban methane (CH4) emissions. Here, we develop a conceptual framework for CH4 mitigation in cities by describing emission processes, the role of measurements, and a need for new institutional partnerships. Urban CH4 emissions are likely to grow with expanding use of natural gas and organic waste disposal systems in growing population centers; however, we currently lack the ability to quantify this increase. We also lack systematic knowledge of the relative contribution of these distinct source sectors on emissions. We present new observations from four North American cities to demonstrate that CH4 emissions vary in magnitude and sector from city to city and hence require different mitigation strategies. Detections of fugitive emissions from these systems suggest that current mitigation approaches are absent or ineffective. These findings illustrate that tackling urban CH4 emissions will require research efforts to identify mitigation targets, develop and implement new mitigation strategies, and monitor atmospheric CH4 levels to ensure the success of mitigation efforts. This research will require a variety of techniques to achieve these objectives and should be deployed in cities globally. We suggest that metropolitan scale partnerships may effectively coordinate systematic measurements and actions focused on emission reduction goals.

Mitigation of methane emissions in cities: How new measurements and partnerships can contribute to emissions reduction strategies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hopkins, Francesca M.; Ehleringer, James R.; Bush, Susan E.

Cities generate 70% of anthropogenic greenhouse gas emissions, a fraction that is grow-ing with global urbanization. While cities play an important role in climate change mitigation, there has been little focus on reducing urban methane (CH4) emissions. Here, we develop a conceptual framework for CH 4 mitigation in cities by describing emission processes, the role of measurements, and a need for new institutional partnerships. Urban CH 4 emissions are likely to grow with expanding use of natural gas and organic waste disposal systems in growing population centers; however, we currently lack the ability to quantify this increase. We also lackmore » systematic knowledge of the relative contribution of these distinct source sectors on emissions. We present new observations from four North American cities to demonstrate that CH4 emissions vary in magnitude and sector from city to city and hence require different mitigation strategies. Detections of fugitive emissions from these systems suggest that current mitiga- tion approaches are absent or ineffective. These findings illustrate that tackling urban CH 4 emissions will require research efforts to identify mitigation targets, develop and implement new mitigation strategies, and monitor atmospheric CH 4 levels to ensure the success of mitigation efforts. This research will require a variety of techniques to achieve these objectives and should be deployed in cities globally. In conclusion, we suggest that metropolitan scale partnerships may effectively coordinate systematic measurements and actions focused on emission reduction goals.« less

A multi-model approach to monitor emissions of CO2 and CO from an urban-industrial complex

NASA Astrophysics Data System (ADS)

Super, Ingrid; Denier van der Gon, Hugo A. C.; van der Molen, Michiel K.; Sterk, Hendrika A. M.; Hensen, Arjan; Peters, Wouter

2017-11-01

Monitoring urban-industrial emissions is often challenging because observations are scarce and regional atmospheric transport models are too coarse to represent the high spatiotemporal variability in the resulting concentrations. In this paper we apply a new combination of an Eulerian model (Weather Research and Forecast, WRF, with chemistry) and a Gaussian plume model (Operational Priority Substances - OPS). The modelled mixing ratios are compared to observed CO2 and CO mole fractions at four sites along a transect from an urban-industrial complex (Rotterdam, the Netherlands) towards rural conditions for October-December 2014. Urban plumes are well-mixed at our semi-urban location, making this location suited for an integrated emission estimate over the whole study area. The signals at our urban measurement site (with average enhancements of 11 ppm CO2 and 40 ppb CO over the baseline) are highly variable due to the presence of distinct source areas dominated by road traffic/residential heating emissions or industrial activities. This causes different emission signatures that are translated into a large variability in observed ΔCO : ΔCO2 ratios, which can be used to identify dominant source types. We find that WRF-Chem is able to represent synoptic variability in CO2 and CO (e.g. the median CO2 mixing ratio is 9.7 ppm, observed, against 8.8 ppm, modelled), but it fails to reproduce the hourly variability of daytime urban plumes at the urban site (R2 up to 0.05). For the urban site, adding a plume model to the model framework is beneficial to adequately represent plume transport especially from stack emissions. The explained variance in hourly, daytime CO2 enhancements from point source emissions increases from 30 % with WRF-Chem to 52 % with WRF-Chem in combination with the most detailed OPS simulation. The simulated variability in ΔCO :  ΔCO2 ratios decreases drastically from 1.5 to 0.6 ppb ppm-1, which agrees better with the observed standard deviation of 0.4 ppb ppm-1. This is partly due to improved wind fields (increase in R2 of 0.10) but also due to improved point source representation (increase in R2 of 0.05) and dilution (increase in R2 of 0.07). Based on our analysis we conclude that a plume model with detailed and accurate dispersion parameters adds substantially to top-down monitoring of greenhouse gas emissions in urban environments with large point source contributions within a ˜ 10 km radius from the observation sites.

Advances in urban-drainage management and flood protection.

PubMed

Verworn, Hans-Reinhard

2002-07-15

Since the beginning of modern urban drainage in the 19th century, the sole objective has been to get rid of sewage and storm water in the best possible way and design the systems according to accepted standards. In recent decades, advanced methods have been developed not only to refine the design but also especially to enable the assessment of hydraulic performance and pollutant emissions. Consequently, urban drainage has become part of an integrated approach concerning flood protection as well as ecological aspects for whole watersheds. Another major change concerns the management of urban systems: simple structural maintenance has been replaced by interactive operational management and control of the systems in order to make better use of the facilities. Rehabilitation has become a multi-objective task. This paper looks at today's basic principles of urban drainage and tomorrow's potential advances, and deals with their relevance to flood protection.

Review of Urban Secondary Organic Aerosol Formation from Gasoline and Diesel Motor Vehicle Emissions.

PubMed

Gentner, Drew R; Jathar, Shantanu H; Gordon, Timothy D; Bahreini, Roya; Day, Douglas A; El Haddad, Imad; Hayes, Patrick L; Pieber, Simone M; Platt, Stephen M; de Gouw, Joost; Goldstein, Allen H; Harley, Robert A; Jimenez, Jose L; Prévôt, André S H; Robinson, Allen L

2017-02-07

Secondary organic aerosol (SOA) is formed from the atmospheric oxidation of gas-phase organic compounds leading to the formation of particle mass. Gasoline- and diesel-powered motor vehicles, both on/off-road, are important sources of SOA precursors. They emit complex mixtures of gas-phase organic compounds that vary in volatility and molecular structure-factors that influence their contributions to urban SOA. However, the relative importance of each vehicle type with respect to SOA formation remains unclear due to conflicting evidence from recent laboratory, field, and modeling studies. Both are likely important, with evolving contributions that vary with location and over short time scales. This review summarizes evidence, research needs, and discrepancies between top-down and bottom-up approaches used to estimate SOA from motor vehicles, focusing on inconsistencies between molecular-level understanding and regional observations. The effect of emission controls (e.g., exhaust aftertreatment technologies, fuel formulation) on SOA precursor emissions needs comprehensive evaluation, especially with international perspective given heterogeneity in regulations and technology penetration. Novel studies are needed to identify and quantify "missing" emissions that appear to contribute substantially to SOA production, especially in gasoline vehicles with the most advanced aftertreatment. Initial evidence suggests catalyzed diesel particulate filters greatly reduce emissions of SOA precursors along with primary aerosol.

Impact of passenger car NOX emissions on urban NO2 pollution - Scenario analysis for 8 European cities

NASA Astrophysics Data System (ADS)

Degraeuwe, Bart; Thunis, Philippe; Clappier, Alain; Weiss, Martin; Lefebvre, Wouter; Janssen, Stijn; Vranckx, Stijn

2017-12-01

Residents of large European cities are exposed to NO2 concentrations that often exceed the established air quality standards. Diesel cars have been identified as a major contributor to this situation; yet, it remains unclear to which levels the NOX emissions of diesel cars have to decrease to effectively mitigate urban NO2 pollution across Europe. Here, we take a continental perspective and model urban NO2 pollution in a generic street canyon of 8 major European cities for various NOX emission scenarios. We find that a reduction in the on-road NOX emissions of diesel cars to the Euro 6 level can in general decrease the regional and urban NO2 concentrations and thereby the frequency of exceedances of the NO2 air quality standard. High NO2 fractions in the NOX emissions of diesel cars tend to increase the urban NO2 concentrations only in proximity of intense road traffic typically found on artery roads in large cities like Paris and London. In cities with a low share of diesel cars in the vehicle fleet such as Athens or a high contribution from the NO2 background to the urban NO2 pollution such as Krakow, measures addressing heavy-duty vehicles, and the manufacturing, energy, and mining industry are necessary to decrease urban air pollution. We regard our model results as robust albeit subject to uncertainty resulting from the application of a generic street layout. With small modifications in the input parameters, our model could be used to assess the impact of NOX emissions from road transport on NO2 air pollution in any European city.

Integral emission factors for methane determined using urban flux measurements and local-scale inverse models

NASA Astrophysics Data System (ADS)

Christen, Andreas; Johnson, Mark; Molodovskaya, Marina; Ketler, Rick; Nesic, Zoran; Crawford, Ben; Giometto, Marco; van der Laan, Mike

2013-04-01

The most important long-lived greenhouse gas (LLGHG) emitted during combustion of fuels is carbon dioxide (CO2), however also traces of the LLGHGs methane (CH4) and nitrous oxide (N2O) are released, the quantities of which depend largely on the conditions of the combustion process. Emission factors determine the mass of LLGHGs emitted per energy used (or kilometre driven for cars) and are key inputs for bottom-up emission modelling. Emission factors for CH4 are typically determined in the laboratory or on a test stand for a given combustion system using a small number of samples (vehicles, furnaces), yet associated with larger uncertainties when scaled to entire fleets. We propose an alternative, different approach - Can integrated emission factors be independently determined using direct micrometeorological flux measurements over an urban surface? If so, do emission factors determined from flux measurements (top-down) agree with up-scaled emission factors of relevant combustion systems (heating, vehicles) in the source area of the flux measurement? Direct flux measurements of CH4 were carried out between February and May, 2012 over a relatively densely populated, urban surface in Vancouver, Canada by means of eddy covariance (EC). The EC-system consisted of an ultrasonic anemometer (CSAT-3, Campbell Scientific Inc.) and two open-path infrared gas analyzers (Li7500 and Li7700, Licor Inc.) on a tower at 30m above the surface. The source area of the EC system is characterised by a relative homogeneous morphometry (5.3m average building height), but spatially and temporally varying emission sources, including two major intersecting arterial roads (70.000 cars drive through the 50% source area per day) and seasonal heating in predominantly single-family houses (natural gas). An inverse dispersion model (turbulent source area model), validated against large eddy simulations (LES) of the urban roughness sublayer, allows the determination of the spatial area that contributes to each measurement interval (30 min), which varies with wind direction and stability. A detailed geographic information system of the urban surface combined with traffic counts and building energy models makes it possible to statistically relate fluxes to vehicle density (km driven) and buildings (gas heated volume) - and ultimately quantify the contribution of space heating, transport sector and fugitive emissions to the total emitted CH4 from an urban environment. The measured fluxes of CH4 over the selected urban environment averaged to 22.8 mg CH4 m-2 day-1 during the study period. Compared with the simultaneously measured CO2 emissions, the contribution of CH4, however, accounts for only about 3% of the total LLGHG emissions from this particular urban surface. Traffic contributed 8.8 mg CH4 m-2 day-1, equivalent to 39% of the total CH4 flux. The determined emission factor for the typical fleet composition is 0.062 g CH4 per km driven which is higher than upscaled fleet emission factors (EPA) by a factor of two. This discrepancy can be partially explained through the slower city traffic with frequent idling (traffic congestion), fleet composition and cold starts. Emissions of CH4 by domestic space heating (55% of the total CH4 flux or 12.7 mg CH4 m-2 day-1) are also higher than estimated from upscaled emission factors. There is no evidence of substantial unknown sources such as soil processes, combustion of wood, and leakages from gas distribution pipes (residual: 6% or 1.3 mg CH4 m-2 day-1). The presented study is among the first direct measurements of CH4 emissions over an urban surface and demonstrates that flux measurements of greenhouse gases can be used to determine sources and emission factors in complex urban situations.

Longwave infrared observation of urban landscapes

NASA Technical Reports Server (NTRS)

Goward, S. N.

1981-01-01

An investigation is conducted regarding the feasibility to develop improved methods for the identification and analysis of urban landscapes on the basis of a utilization of longwave infrared observations. Attention is given to landscape thermal behavior, urban thermal properties, modeled thermal behavior of pavements and buildings, and observed urban landscape thermal emissions. The differential thermal behavior of buildings, pavements, and natural areas within urban landscapes is found to suggest that integrated multispectral solar radiant reflectance and terrestrial radiant emissions data will significantly increase potentials for analyzing urban landscapes. In particular, daytime satellite observations of the considered type should permit better identification of urban areas and an analysis of the density of buildings and pavements within urban areas. This capability should enhance the utility of satellite remote sensor data in urban applications.

Greenhouse gas emission accounting and management of low-carbon community.

PubMed

Song, Dan; Su, Meirong; Yang, Jin; Chen, Bin

2012-01-01

As the major source of greenhouse gas (GHG) emission, cities have been under tremendous pressure of energy conservation and emission reduction for decades. Community is the main unit of urban housing, public facilities, transportation, and other properties of city's land use. The construction of low-carbon community is an important pathway to realize carbon emission mitigation in the context of rapid urbanization. Therefore, an efficient carbon accounting framework should be proposed for CO₂ emissions mitigation at a subcity level. Based on life-cycle analysis (LCA), a three-tier accounting framework for the carbon emissions of the community is put forward, including emissions from direct fossil fuel combustion, purchased energy (electricity, heat, and water), and supply chain emissions embodied in the consumption of goods. By compiling a detailed CO₂ emission inventory, the magnitude of carbon emissions and the mitigation potential in a typical high-quality community in Beijing are quantified within the accounting framework proposed. Results show that emissions from supply chain emissions embodied in the consumption of goods cannot be ignored. Specific suggestions are also provided for the urban decision makers to achieve the optimal resource allocation and further promotion of low-carbon communities.

Greenhouse Gas Emission Accounting and Management of Low-Carbon Community

PubMed Central

Song, Dan; Su, Meirong; Yang, Jin; Chen, Bin

2012-01-01

As the major source of greenhouse gas (GHG) emission, cities have been under tremendous pressure of energy conservation and emission reduction for decades. Community is the main unit of urban housing, public facilities, transportation, and other properties of city's land use. The construction of low-carbon community is an important pathway to realize carbon emission mitigation in the context of rapid urbanization. Therefore, an efficient carbon accounting framework should be proposed for CO2 emissions mitigation at a subcity level. Based on life-cycle analysis (LCA), a three-tier accounting framework for the carbon emissions of the community is put forward, including emissions from direct fossil fuel combustion, purchased energy (electricity, heat, and water), and supply chain emissions embodied in the consumption of goods. By compiling a detailed CO2 emission inventory, the magnitude of carbon emissions and the mitigation potential in a typical high-quality community in Beijing are quantified within the accounting framework proposed. Results show that emissions from supply chain emissions embodied in the consumption of goods cannot be ignored. Specific suggestions are also provided for the urban decision makers to achieve the optimal resource allocation and further promotion of low-carbon communities. PMID:23251104

Diurnal profiles of isoprene, methacrolein and methyl vinyl ketone at an urban site in Hong Kong

NASA Astrophysics Data System (ADS)

Cheung, K.; Guo, H.; Ou, J. M.; Simpson, I. J.; Barletta, B.; Meinardi, S.; Blake, D. R.

2014-02-01

Methacrolein (MACR) and methyl vinyl ketone (MVK) are major oxidation products of isoprene, but they also have primary emissions in urban environments, for example from fuel use. To examine whether MACR and MVK could be used as a direct measurement of the oxidation rate of isoprene in an urban setting, the diurnal variations of isoprene, MACR and MVK were characterized at an urban site in Hong Kong from September to November, 2010. Ozone (O3), carbon monoxide (CO), sulfur dioxide (SO2), and nitrogen oxides (NOx) were simultaneously monitored. The average isoprene mixing ratio was 252 ± 204 pptv, with a bell-shaped distribution observed on most sampling days. Higher levels of isoprene were recorded in the beginning of the sampling period, when the temperature was higher. The average mixing ratios of MACR and MVK were 101 ± 85 pptv and 175 ± 131 pptv, respectively. While isoprene, MACR and MVK experienced peak concentrations from 11 a.m. to 3 p.m., increased levels of MACR and MVK during the morning rush hour did not coincide with isoprene. The low associations between isoprene and MACR/MVK suggest that either MACR/MVK were not formed from local isoprene oxidation and/or they could partly originate from primary emissions such as fuel evaporation or combustion. Statistical analyses of linear regression and positive matrix factorization revealed that approximately 20-29% of the measured MACR and MVK was associated with biogenic emissions, and 55-71% was impacted by vehicular emissions, particularly during morning rush hours. Since MACR and MVK originated from both primary emissions and biogenic emissions at this urban site, they can therefore overestimate the actual rate of isoprene oxidation and its contribution to O3 production in urban areas with strong primary emissions.

Distinguishing the roles of meteorology, emission control measures, regional transport, and co-benefits of reduced aerosol feedbacks in ;APEC Blue;

NASA Astrophysics Data System (ADS)

Gao, Meng; Liu, Zirui; Wang, Yuesi; Lu, Xiao; Ji, Dongsheng; Wang, Lili; Li, Meng; Wang, Zifa; Zhang, Qiang; Carmichael, Gregory R.

2017-10-01

Air quality are strongly influenced by both emissions and meteorological conditions. During the Asia Pacific Economic Cooperation (APEC) week (November 5-11, 2014), the Chinese government implemented unprecedented strict emission control measures in Beijing and surrounding provinces, and then a phenomenon referred to as ;APEC Blue; (rare blue sky) occurred. It is challenging to quantify the effectiveness of the implemented strict control measures solely based on observations. In this study, we use the WRF-Chem model to distinguish the roles of meteorology, emission control measures, regional transport, and co-benefits of reduced aerosol feedbacks during APEC week. In general, meteorological variables, PM2.5 concentrations and PM2.5 chemical compositions are well reproduced in Beijing. Positive weather conditions (lower temperature, lower relative humidity, higher wind speeds and enhanced boundary layer heights) play important roles in ;APEC Blue;. Applying strict emission control measures in Beijing and five surrounding provinces can only explain an average decrease of 17.7 μg/m3 (-21.8%) decreases in PM2.5 concentrations, roughly more than half of which is caused by emission controls that implemented in the five surrounding provinces (12.5 μg/m3). During the APEC week, non-local emissions contributed to 41.3% to PM2.5 concentrations in Beijing, and the effectiveness of implementing emission control measures hinges on dominant pathways and transport speeds. Besides, we also quantified the contribution of reduced aerosol feedbacks due to strict emission control measures in this study. During daytime, co-benefits of reduced aerosol feedbacks account for about 10.9% of the total decreases in PM2.5 concentrations in urban Beijing. The separation of contributions from aerosol absorption and scattering restates the importance of controlling BC to accelerate the effectiveness of aerosol pollution control.

Cities, traffic, and CO2: A multidecadal assessment of trends, drivers, and scaling relationships

PubMed Central

Gately, Conor K.; Hutyra, Lucy R.; Sue Wing, Ian

2015-01-01

Emissions of CO2 from road vehicles were 1.57 billion metric tons in 2012, accounting for 28% of US fossil fuel CO2 emissions, but the spatial distributions of these emissions are highly uncertain. We develop a new emissions inventory, the Database of Road Transportation Emissions (DARTE), which estimates CO2 emitted by US road transport at a resolution of 1 km annually for 1980–2012. DARTE reveals that urban areas are responsible for 80% of on-road emissions growth since 1980 and for 63% of total 2012 emissions. We observe nonlinearities between CO2 emissions and population density at broad spatial/temporal scales, with total on-road CO2 increasing nonlinearly with population density, rapidly up to 1,650 persons per square kilometer and slowly thereafter. Per capita emissions decline as density rises, but at markedly varying rates depending on existing densities. We make use of DARTE’s bottom-up construction to highlight the biases associated with the common practice of using population as a linear proxy for disaggregating national- or state-scale emissions. Comparing DARTE with existing downscaled inventories, we find biases of 100% or more in the spatial distribution of urban and rural emissions, largely driven by mismatches between inventory downscaling proxies and the actual spatial patterns of vehicle activity at urban scales. Given cities’ dual importance as sources of CO2 and an emerging nexus of climate mitigation initiatives, high-resolution estimates such as DARTE are critical both for accurately quantifying surface carbon fluxes and for verifying the effectiveness of emissions mitigation efforts at urban scales. PMID:25847992

Computational fluid dynamics (CFD) simulation of CO2 emission from a thermal power plant in an urban environment.

NASA Astrophysics Data System (ADS)

Toja-Silva, Francisco; Chen, Jia; Hachinger, Stephan

2017-04-01

Climate change, a societal challenge for the European Union, is affecting all regions in Europe and has a profound impact on society and environment. It is now clear that the present global warming period is due to the strong anthropogenic greenhouse gas (GHG) emission, occurring at an unprecedented rate. Therefore, the identification and control of the greenhouse gas sources has a great relevance. Since the GHG emissions from cities are the largest human contribution to climate change, the present investigation focuses on the urban environment. Bottom-up annual emission inventories are compiled for most countries. However, a rigorous approach requires to perform experimental measurements in order to verify the official estimates. Measurements of column-averaged dry-air mole fractions of GHG (XGHG) can be used for this. To comprehensively detect and quantify GHG emission sources, these punctual column data, however, have to be extended to the surrounding urban map, requiring a deep understanding of the gas transport. The resulting emission estimation will serve several practical purposes, e.g. the verification of official emission rates and the determination of trends in urban emissions. They will enable the administration to make targeted and economically efficient decisions about mitigation options, and help to stop unintentional and furtive releases. With this aim, this investigation presents a completely new approach to the analysis of the carbon dioxide (CO2) emissions from fossil fuel thermal power plants in urban environments by combining differential column measurements with computational fluid dynamics (CFD) simulations in order to deeply understand the experimental conditions. The case study is a natural gas-fueled cogeneration (combined heat and power, CHP) thermal power plant inside the city of Munich (Germany). The software used for the simulations (OpenFOAM) was modified in order to use the most advanced RANS turbulence modeling (i.e. Durbin) and parametrization for the fluid flow, and to consider the turbulent eddy dissipation for gas transport and diffusion. Turbulence and gas transport and diffusion modeling are initially validated by reproducing a wind-tunnel benchmark case. The full-scale simulation results are compared with the Gaussian plume model, and an improvement of such model is suggested for being used in the urban environment. CFD resolves the turbulent eddy dissipation phenomena that enhance the gas diffusion close to building roofs, which is not considered by the Gaussian model. The results are also compared with experimental measurements of XCO2 on the site. The XCO2 is calculated from the simulation results both considering a vertical column and the real axis of measurement at that time. The results show that the XCO2 values expected for a vertical column are less representative for the measurement, but the real measurement axis angle needs to be considered. These results help to design experimental strategies in future campaigns. In addition, CO2 concentration maps for the city are obtained from the simulations. These concentration maps are presented and the CO2 spatial distribution is analyzed.

Positioning infrastructure and technologies for low-carbon urbanization

NASA Astrophysics Data System (ADS)

Chester, Mikhail V.; Sperling, Josh; Stokes, Eleanor; Allenby, Braden; Kockelman, Kara; Kennedy, Christopher; Baker, Lawrence A.; Keirstead, James; Hendrickson, Chris T.

2014-10-01

The expected urbanization of the planet in the coming century coupled with aging infrastructure in developed regions, increasing complexity of man-made systems, and pressing climate change impacts have created opportunities for reassessing the role of infrastructure and technologies in cities and how they contribute to greenhouse gas (GHG) emissions. Modern urbanization is predicated on complex, increasingly coupled infrastructure systems, and energy use continues to be largely met from fossil fuels. Until energy infrastructures evolve away from carbon-based fuels, GHG emissions are critically tied to the urbanization process. Further complicating the challenge of decoupling urban growth from GHG emissions are lock-in effects and interdependencies. This paper synthesizes state-of-the-art thinking for transportation, fuels, buildings, water, electricity, and waste systems and finds that GHG emissions assessments tend to view these systems as static and isolated from social and institutional systems. Despite significant understanding of methods and technologies for reducing infrastructure-related GHG emissions, physical, institutional, and cultural constraints continue to work against us, pointing to knowledge gaps that must be addressed. This paper identifies three challenge themes to improve our understanding of the role of infrastructure and technologies in urbanization processes and position these increasingly complex systems for low-carbon growth. The challenges emphasize how we can reimagine the role of infrastructure in the future and how people, institutions, and ecological systems interface with infrastructure.

Greenhouse gas emissions from integrated urban drainage systems: Where do we stand?

NASA Astrophysics Data System (ADS)

Mannina, Giorgio; Butler, David; Benedetti, Lorenzo; Deletic, Ana; Fowdar, Harsha; Fu, Guangtao; Kleidorfer, Manfred; McCarthy, David; Steen Mikkelsen, Peter; Rauch, Wolfgang; Sweetapple, Chris; Vezzaro, Luca; Yuan, Zhiguo; Willems, Patrick

2018-04-01

As sources of greenhouse gas (GHG) emissions, integrated urban drainage systems (IUDSs) (i.e., sewer systems, wastewater treatment plants and receiving water bodies) contribute to climate change. This paper, produced by the International Working Group on Data and Models, which works under the IWA/IAHR Joint Committee on Urban Drainage, reviews the state-of-the-art and modelling tools developed recently to understand and manage GHG emissions from IUDS. Further, open problems and research gaps are discussed and a framework for handling GHG emissions from IUDSs is presented. The literature review reveals that there is a need to strengthen already available mathematical models for IUDS to take GHG into account.

Production, distribution, and cost of oxygenated gasoline blends as a CO control strategy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Holmes, J.G; Dworsky, B.S.

1988-01-01

During the past two decades, efforts to reduce the contribution of automotive emissions to air pollution have focused principally on the development of more stringent emission standards for new vehicles, and the use of inspection and maintenance (I/M) programs. Despite the achievements in the last few years, motor vehicles have remained a major source of air pollution in urban areas. Further reductions in either the emission standards or in I/M program pass/fail cutpoints are not politically feasible, and alternative methods to achieve emission reductions are being investigated. One potential method is through the use of alternative fuels that can reducemore » tailpipe emissions. For example, the addition of alcohol or ether into gasoline has been shown to lean out the engine and cut carbon monoxide emissions. This paper compares the costs of producing and distribution methanol, ethanol, and MTBE blends as part of a carbon monoxide control strategy. It addresses the costs of production, distribution, infrastructure development, and retailing associated with each fuel blend.« less

Assessing Greenhouse Gas emissions in the Greater Toronto Area using atmospheric observations (Invited)

NASA Astrophysics Data System (ADS)

Vogel, F. R.; Chan, E.; Huang, L.; Levin, I.; Worthy, D.

2013-12-01

Urban areas are said to be responsible for approximately 75% of anthropogenic Greenhouse Gases (GHGs) emissions while comprising only two percent of the land area [1]. This limited spatial expansion should facilitate a monitoring of anthropogenic GHGs from atmospheric observations. As major sources of emissions, cities also have a huge potential to drive emissions reductions. To effectively manage emissions, cities must however, first measure and report these publicly [2]. Modelling studies and measurements of CO2 from fossil fuel burning (FFCO2) in densely populated areas does, however, pose several challenges: Besides continuous in-situ observations, i.e. finding an adequate atmospheric transport model, a sufficiently fine-grained FFCO2 emission model and the proper background reference observations to distinguish the large-scale from the local/urban contributions to the observed FFCO2 concentration offsets ( ΔFFCO2) are required. Pilot studies which include the data from two 'sister sites*' in the vicinity of Toronto, Canada helped to derive flux estimates for Non-CO2 GHGs [3] and improve our understanding of urban FFCO2 emissions. Our 13CO2 observations reveal that the contribution of natural gas burning (mostly due to domestic heating) account for 80%×7% of FFCO2 emissions in the Greater Toronto Area (GTA) during winter. Our 14CO2 observations in the GTA, furthermore, show that the local offset of CO2 (ΔCO2) between our two sister sites can be largely attributed to urban FFCO2 emissions. The seasonal cycle of the observed ΔFFCO2 in Toronto, combined with high-resolution atmospheric modeling, helps to independently assess the contribution from different emission sectors (transportation, primary energy and industry, domestic heating) as predicted by a dedicated city-scale emission inventory, which deviates from a UNFCCC-based inventory. [1] D. Dodman. 2009. Blaming cities for climate change? An analysis of urban greenhouse gas emissions inventories. Environment and Urbanization, 21,185. [2] Arikan Y., Desaim R., Bhatia P. and W. K. Fong, 2012 Global Protocol for Community-Scale Greenhouse Gas Emissions (GPC), C40 Cities Climate Leadership group, available at: http://www.c40.org [3] Vogel, F. R., Ishizawa, M., Chan, E., Chan, D., Hammer, S., Levin, I., & Worthy, D. E. J. (2012). Regional non-CO2 greenhouse gas fluxes inferred from atmospheric measurements in Ontario, Canada. Journal of Integrative Environmental Sciences, 9(1), 41-55. *The term 'sister sites' refers to sites that share a common background signal (i.e. common large scale influence), while significantly differing sensitivities to urban GHG emissions. In our case: Egbert, Ontario and Downsview, Toronto, Ontario.

Dense downtown living more carbon intense due to higher consumption: a case study of Helsinki

NASA Astrophysics Data System (ADS)

Heinonen, Jukka; Kyrö, Riikka; Junnila, Seppo

2011-07-01

Hindering urban sprawl is one of the main goals for contemporary urban planning. Urban density is considered crucial in climate change mitigation since it reduces automobile dependence and decreases unit sizes, for example. This letter analyzes the effect of density in a city context. In the study the Finnish capital Helsinki is divided into two areas of different urban densities: the high density downtown area and the more scarcely populated suburbs. The study is a continuation of a recently published study on the implications of urban structure on carbon emissions, and analyzes further the main finding of the first study—that higher urban density might have negligible or even reverse effect on the per capita carbon emissions. Similarly to the previous study, a consumption based tiered hybrid life cycle assessment (LCA) approach is employed in order to produce a comprehensive assessment, free of territorial boundaries and system cutoffs typical of traditional LCAs. Based on the findings of the previous study, it is hypothesized that when assessing city level carbon dioxide emissions from a wider, consumer oriented LCA perspective, increased urban density may not necessarily reduce carbon emissions. Surprisingly, the study finds that carbon dioxide equivalent (CO2e) emissions are substantially higher in the dense downtown area than in the surrounding suburbs, which is suggested to imply that the increased consumption due to the higher standard of living increases emissions more than the higher density is able to reduce them. The results demonstrate that, while increasing urban density can be justified from a number of ecological, social and economic viewpoints, density is not necessarily a key parameter in the particular case of climate change. In cities like Helsinki, where wealth is concentrated in the downtown area, climate policies should give higher priority to the energy consumption of buildings, to alternative energy production and distribution modes, as well as to low carbon consumption within the city.

High-resolution mapping of biogenic carbon fluxes to improve urban CO2 monitoring, reporting, and verification

NASA Astrophysics Data System (ADS)

Hardiman, B. S.; Hutyra, L.; Gately, C.; Raciti, S. M.

2014-12-01

Urban areas are home to 80% of the US population and 70% of energy related fossil fuel emissions originate from urban areas. Efforts to accurately monitor, report, and verify anthropogenic CO2 missions using atmospheric measurements require reliable partitioning of anthropogenic and biogenic sources. Anthropogenic emissions peak during the daytime, coincident with biogenic drawdown of CO2. In contrast, biogenic respiration emissions peak at night when anthropogenic emissions are lower. This temporal aliasing of fluxes requires careful modeling of both biogenic and anthropogenic fluxes for accurate source attribution through inverse modeling. Biogenic fluxes in urban regions can be a significant component of the urban carbon cycle. However, vegetation in urban areas is subject to longer growing seasons, reduced competition, higher rates of nitrogen deposition, and altered patterns of biomass inputs, all interacting to elevate C turnover rates relative to analogous non-urban ecosystems. These conditions suggest that models that ignore urban vegetation or base biogenic flux estimates on non-urban forests are likely to produce inaccurate estimates of anthropogenic CO2 emissions. Biosphere models often omit biogenic fluxes in urban areas despite potentially extensive vegetation coverage. For example, in Massachusetts, models mask out as much as 40% of land area, effectively assuming they have no biological flux. This results in a ~32% underestimate of aboveground biomass (AGB) across the state as compared to higher resolution vegetation maps. Our analysis suggests that some common biomass maps may underestimate forest biomass by ~520 Tg C within the state of Massachusetts. Moreover, omitted portions of the state have the highest population density, indicating that we know least about regions where most people live. We combine remote sensing imagery of urban vegetation cover with ground surveys of tree growth and mortality to improve estimates of aboveground biomass and biogenic flux rates. Updated biogenic flux rates are combined with spatially explicit anthropogenic flux estimates and a network of urban CO2 monitoring sites as the foundation for a novel carbon monitoring system spanning the Boston-Washington D.C. metropolitan corridor.

Carbon emissions tax policy of urban road traffic and its application in Panjin, China

PubMed Central

Yang, Longhai; Fang, Lin

2018-01-01

How to effectively solve traffic congestion and transportation pollution in urban development is a main research emphasis for transportation management agencies. A carbon emissions tax can affect travelers’ generalized costs and will lead to changes in passenger demand, mode choice and traffic flow equilibrium in road networks, which are of significance in green travel and low-carbon transportation management. This paper first established a mesoscopic model to calculate the carbon emissions tax and determined the value of this charge in China, which was based on road traffic flow, vehicle speed, and carbon emissions. Referring to existing research results to calibrate the value of time, this paper modified the traveler’s generalized cost function, including the carbon emissions tax, fuel surcharge and travel time cost, which can be used in the travel impedance model with the consideration of the carbon emissions tax. Then, a method for analyzing urban road network traffic flow distribution was put forward, and a joint traffic distribution model was established, which considered the relationship between private cars and taxis. Finally, this paper took the city of Panjin as an example to analyze the road traffic carbon emissions tax’s impact. The results illustrated that the carbon emissions tax has a positive effect on road network flow equilibrium and carbon emission reduction. This paper will have good reference value and practical significance for the calculation and implementation of urban traffic carbon emissions taxes in China. PMID:29738580

Carbon emissions tax policy of urban road traffic and its application in Panjin, China.

PubMed

Yang, Longhai; Hu, Xiaowei; Fang, Lin

2018-01-01

How to effectively solve traffic congestion and transportation pollution in urban development is a main research emphasis for transportation management agencies. A carbon emissions tax can affect travelers' generalized costs and will lead to changes in passenger demand, mode choice and traffic flow equilibrium in road networks, which are of significance in green travel and low-carbon transportation management. This paper first established a mesoscopic model to calculate the carbon emissions tax and determined the value of this charge in China, which was based on road traffic flow, vehicle speed, and carbon emissions. Referring to existing research results to calibrate the value of time, this paper modified the traveler's generalized cost function, including the carbon emissions tax, fuel surcharge and travel time cost, which can be used in the travel impedance model with the consideration of the carbon emissions tax. Then, a method for analyzing urban road network traffic flow distribution was put forward, and a joint traffic distribution model was established, which considered the relationship between private cars and taxis. Finally, this paper took the city of Panjin as an example to analyze the road traffic carbon emissions tax's impact. The results illustrated that the carbon emissions tax has a positive effect on road network flow equilibrium and carbon emission reduction. This paper will have good reference value and practical significance for the calculation and implementation of urban traffic carbon emissions taxes in China.

Assessment of discrepancies between bottom-up and regional emission inventories in Norwegian urban areas

NASA Astrophysics Data System (ADS)

López-Aparicio, Susana; Guevara, Marc; Thunis, Philippe; Cuvelier, Kees; Tarrasón, Leonor

2017-04-01

This study shows the capabilities of a benchmarking system to identify inconsistencies in emission inventories, and to evaluate the reason behind discrepancies as a mean to improve both bottom-up and downscaled emission inventories. Fine scale bottom-up emission inventories for seven urban areas in Norway are compared with three regional emission inventories, EC4MACS, TNO_MACC-II and TNO_MACC-III, downscaled to the same areas. The comparison shows discrepancies in nitrogen oxides (NOx) and particulate matter (PM2.5 and PM10) when evaluating both total and sectorial emissions. The three regional emission inventories underestimate NOx and PM10 traffic emissions by approximately 20-80% and 50-90%, respectively. The main reasons for the underestimation of PM10 emissions from traffic in the regional inventories are related to non-exhaust emissions due to resuspension, which are included in the bottom-up emission inventories but are missing in the official national emissions, and therefore in the downscaled regional inventories. The benchmarking indicates that the most probable reason behind the underestimation of NOx traffic emissions by the regional inventories is the activity data. The fine scale NOx traffic emissions from bottom-up inventories are based on the actual traffic volume at the road link and are much higher than the NOx emissions downscaled from national estimates based on fuel sales and based on population for the urban areas. We have identified important discrepancies in PM2.5 emissions from wood burning for residential heating among all the inventories. These discrepancies are associated with the assumptions made for the allocation of emissions. In the EC4MACs inventory, such assumptions imply high underestimation of PM2.5 emissions from the residential combustion sector in urban areas, which ranges from 40 to 90% compared with the bottom-up inventories. The study shows that in three of the seven Norwegian cities there is need for further improvement of the emission inventories.

Consolidated Navy-Marines Environmental Law Deskbook. Revised

DTIC Science & Technology

1994-05-01

106 ????? 1505 (1992)) FGD Flue Gas Desulfurization FGS Final Governing Standards FICUN Federal Interagency Committee on Urban Noise FIFRA Federal...SIPs. A. SIP management. Each SIP must be approved by EPA and must contain a mix of controls and strategies sufficient to achieve and maintain the...and contain release. Identify the parties carrying out response. If none, state why. EXAMPLE: Gas barriers used to control and contain vapor emissions

Rice emissions during field flooding and air pollution feedbacks across South Korea

NASA Astrophysics Data System (ADS)

So, C.; Diskin, G. S.; DiGangi, J. P.; Choi, Y.; Rana, M.; Hughes, S.; Blake, D. R.; Nault, B.; Schroeder, J.; Campuzano Jost, P.; Jimenez, J. L.; Kim, M. J.; Teng, A.; Crounse, J. D.; Wenneberg, P.; Kaser, L.; Mikoviny, T.; Müller, M.; Wisthaler, A.; Pusede, S. E.

2017-12-01

Nitrous oxide (N2O) and methane (CH4) are important long-lived greenhouse gases. Known anthropogenic sources of these gases include rice cultivation, which represents anywhere between 5% and 20% of methane emissions globally. Other volatile molecules are also produced by soil biogeochemistry when rice fields are flooded, including small organic oxygenates. Here, we use recent aircraft measurements from the KORUS-AQ experiment to describe controls over rice emissions of N2O and CH4 at regional-scales across the South Korean Peninsula. We also investigate potential emissions of molecular hydrogen and volatile alcohols and organic acids and consider the effect of aerosol nitrate and sulfate deposition on rice soil biogeochemistry on paddies downwind of polluted urban areas.

Historic and future trends of vehicle emissions in Beijing, 1998-2020: A policy assessment for the most stringent vehicle emission control program in China

NASA Astrophysics Data System (ADS)

Zhang, Shaojun; Wu, Ye; Wu, Xiaomeng; Li, Mengliang; Ge, Yunshan; Liang, Bin; Xu, Yueyun; Zhou, Yu; Liu, Huan; Fu, Lixin; Hao, Jiming

2014-06-01

As a pioneer in controlling vehicle emissions within China, Beijing released the Clean Air Action Plan 2013-2017 document in August 2013 to improve its urban air quality. It has put forward this plan containing the most stringent emission control policies and strategies to be adopted for on-road vehicles of Beijing. This paper estimates the historic and future trends and uncertainties in vehicle emissions of Beijing from 1998 to 2020 by applying a new emission factor model for the Beijing vehicle fleet (EMBEV). Our updated results show that total emissions of CO, THC, NOx and PM2.5 from the Beijing vehicle fleet are 507 (395-819) kt, 59.1 (41.2-90.5) kt, 74.7 (54.9-103.9) kt and 2.69 (1.91-4.17) kt, respectively, at a 95% confidence level. This represents significant reductions of 58%, 59%, 31% and 62%, respectively, relative to the total vehicle emissions in 1998. The past trends clearly posed a challenge to NOx emission mitigation for the Beijing vehicle fleet, especially in light of those increasing NOx emissions from heavy-duty diesel vehicles (HDDVs) which have partly offset the reduction benefit from light-duty gasoline vehicles (LDGVs). Because of recently announced vehicle emission controls to be adopted in Beijing, including tighter emissions standards, limitations on vehicle growth by more stringent license control, promotion of alternative fuel technologies (e.g., natural gas) and the scrappage of older vehicles, estimated vehicle emissions in Beijing will continue to be mitigated by 74% of CO, 68% of THC, 56% of NOx and 72% of PM2.5 in 2020 compared to 2010 levels. Considering that many of the megacities in China are facing tremendous pressures to mitigate emissions from on-road vehicles, our assessment will provide a timely case study of significance for policy-makers in China.

Quantifying the emissions of HCN from on-road vehicles in urban areas

NASA Astrophysics Data System (ADS)

Moussa, S. G.; Leithead, A.; Wentzell, J. J.; Lu, G.; Li, S.; Brook, J.; Liggio, J.

2013-12-01

Hydrogen Cyanide (HCN), has been considered a marker for biomass burning emissions. Despite its adverse health impacts, estimate of its global sources and sinks are highly uncertain due to a limited number of field and laboratory studies. In particular, HCN emissions from automobile exhaust are not well constrained for modern vehicles, and thought to be relatively small compared to emissions from biomass burning. In the current study, HCN emissions from individual diesel and gasoline vehicles were quantified as a function of engine driving mode, and fuel type. Proton transfer Reaction-Time of Flight-Mass spectrometry (PTR-ToF-MS) was used to measure HCN emissions from diesel engines operating on ultra-low sulfur diesel (ULSD) and various bio-diesel blends including Soy, Tallow, and Canola. Significant emissions of HCN were observed from all vehicles, and enhanced with the use of biodiesel. In addition, ambient measurements of HCN in a traffic dominated urban area in Toronto, Canada demonstrated that a correlation between HCN, and traditional vehicle emissions markers such as benzene and xylenes exists and indicating that HCN has the potential to be a marker of fuel combustion. The ambient data and the calculated emission factors further suggest that vehicular emissions are a major source of HCN even in the presence of biomass burning, and that near roadway conditions may represent the dominant exposure pathway to HCN in urban areas. Results of this study have important implications on HCN global budget, health impacts in urban areas and the effect of alternate fuels on the emissions of this toxic species.

An impact assessment of sustainable technologies for the Chinese urban residential sector at provincial level

NASA Astrophysics Data System (ADS)

Xing, Rui; Hanaoka, Tatsuya; Kanamori, Yuko; Dai, Hancheng; Masui, Toshihiko

2015-06-01

Recently, energy use in the urban residential sector of China has drastically increased due to higher incomes and urbanization. The fossil fuels dominant energy supply has since worsened the air quality, especially in urban areas. In this study we estimate the future energy service demands in Chinese urban residential areas, and then use an AIM/Enduse model to evaluate the emission reduction potential of CO2, SO2, NOx and PM. Considering the climate diversity and its impact on household energy service demands, our analysis is down-scaled to the provincial-level. The results show that in most of the regions, penetration of efficient technologies will bring CO2 emission reductions of over 20% compared to the baseline by the year 2030. Deployment of energy efficient technologies also co-benefits GHG emission reduction. However, efficient technology selection appears to differ across provinces due to climatic variation and economic disparity. For instance, geothermal heating technology is effective for the cold Northern areas while biomass technology contributes to emission reduction the most in the warm Southern areas.

Benchmarking Anthropogenic Heavy Metals Emissions: Australian and Global Urban Environmental Health Risk Based Indicators of Sustainability

ERIC Educational Resources Information Center

Dejkovski, Nick

2016-01-01

In Australia, the impacts of urbanisation and human activity are evident in increased waste generation and the emissions of metals into the air, land or water. Metals that have accumulated in urban soils almost exclusively anthropogenically can persist for long periods in the environment. Anthropogenic waste emissions containing heavy metals are a…

A Spatial Panel Data Analysis of Economic Growth, Urbanization, and NOx Emissions in China

PubMed Central

Ge, Xiangyu; Zhou, Yanli; Liu, Songlin

2018-01-01

Is nitrogen oxides emissions spatially correlated in a Chinese context? What is the relationship between nitrogen oxides emission levels and fast-growing economy/urbanization? More importantly, what environmental preservation and economic developing policies should China’s central and local governments take to mitigate the overall nitrogen oxides emissions and prevent severe air pollution at the provincial level in specific locations and their neighboring areas? The present study aims to tackle these issues. This is the first research that simultaneously studies the nexus between nitrogen oxides emissions and economic development/urbanization, with the application of a spatial panel data technique. Our empirical findings suggest that spatial dependence of nitrogen oxides emissions distribution exists at the provincial level. Through the investigation of the existence of an environmental Kuznets curve (EKC) embedded within the Stochastic Impacts by Regression on Population, Affluence, and Technology (STIRPAT) framework, we conclude something interesting: an inverse N-shaped EKC describes both the income-nitrogen oxides nexus and the urbanization-nitrogen oxides nexus. Some well-directed policy advice is provided to reduce nitrogen oxides in the future. Moreover, these results contribute to the literature on development and pollution. PMID:29641500

Motorcycle emissions and fuel consumption in urban and rural driving conditions.

PubMed

Chen, K S; Wang, W C; Chen, H M; Lin, C F; Hsu, H C; Kao, J H; Hu, M T

2003-08-01

This work reports sampling of motorcycle on-road driving cycles in actual urban and rural environments and the development of representative driving cycles using the principle of least total variance in individual regions. Based on the representative driving cycles in individual regions, emission factors for carbon monoxide (CO), hydrocarbons (HC), nitrogen oxides (NO(x)=NO+NO(2)) and carbon dioxide (CO(2)), as well as fuel consumption, were determined using a chassis dynamometer. The measurement results show that the representative driving cycles are almost identical in the three largest cities in Taiwan, but they differ significantly from the rural driving cycle. Irrespective of driving conditions, emission factors differ insignificantly between the urban and rural regions at a 95% confidence level. However, the fuel consumption in urban centers is approximately 30% higher than in the rural regions, with driving conditions in the former usually poor compared to the latter. Two-stroke motorcycles generally have considerably higher HC emissions and quite lower NO(x) emissions than those of four-stroke motorcycles. Comparisons with other studies suggest that factors such as road characteristics, traffic volume, vehicle type, driving conditions and driver behavior may affect motorcycle emission levels in real traffic situations.

A Spatial Panel Data Analysis of Economic Growth, Urbanization, and NOx Emissions in China.

PubMed

Ge, Xiangyu; Zhou, Zhimin; Zhou, Yanli; Ye, Xinyue; Liu, Songlin

2018-04-11

Abstract : Is nitrogen oxides emissions spatially correlated in a Chinese context? What is the relationship between nitrogen oxides emission levels and fast-growing economy/urbanization? More importantly, what environmental preservation and economic developing policies should China's central and local governments take to mitigate the overall nitrogen oxides emissions and prevent severe air pollution at the provincial level in specific locations and their neighboring areas? The present study aims to tackle these issues. This is the first research that simultaneously studies the nexus between nitrogen oxides emissions and economic development/urbanization, with the application of a spatial panel data technique. Our empirical findings suggest that spatial dependence of nitrogen oxides emissions distribution exists at the provincial level. Through the investigation of the existence of an environmental Kuznets curve (EKC) embedded within the Stochastic Impacts by Regression on Population, Affluence, and Technology (STIRPAT) framework, we conclude something interesting: an inverse N-shaped EKC describes both the income-nitrogen oxides nexus and the urbanization-nitrogen oxides nexus. Some well-directed policy advice is provided to reduce nitrogen oxides in the future. Moreover, these results contribute to the literature on development and pollution.

A new approach to quantify and map carbon stored, sequestered and emissions avoided by urban forests

Treesearch

E. Gregory McPherson; Qingfu Xiao; Elena Aguaron

2013-01-01

This paper describes the use of field surveys, biometric information for urban tree species and remote sensing to quantify and map carbon (C) storage, sequestration and avoided emissions from energy savings. Its primary contribution is methodological; the derivation and application of urban tree canopy (UTC) based transfer functions (t C ha-1 UTC). Findings for Los...

Spatial boundary of urban ‘acid islands’ in southern China

PubMed Central

Du, E.; de Vries, W.; Liu, X.; Fang, J.; Galloway, J. N.; Jiang, Y.

2015-01-01

Elevated emissions of sulfur dioxide, nitrogen oxides and ammonia in China have resulted in high levels of sulfur and nitrogen deposition, being contributors to soil acidification, especially in and near large cities. However, knowledge gaps still exist in the way that large cities shape spatial patterns of acid deposition. Here, we assessed the patterns of pH, sulfate, nitrate and ammonium in bulk precipitation and throughfall in southern China’s forests by synthesizing data from published literature. Concentrations and fluxes of sulfate, nitrate and ammonium in bulk precipitation and throughfall exhibited a power-law increase with a closer distance to the nearest large cities, and accordingly pH showed a logarithmic decline. Our findings indicate the occurrence of urban ‘acid islands’ with a critical radius of approximately 70 km in southern China, receiving potential acid loads of more than 2 keq ha−1 yr−1. These urban acid islands covered an area of 0.70 million km2, accounting for nearly 30% of the land area in southern China. Despite a significant capacity to neutralize acids in precipitation, our analysis highlights a substantial contribution of ammonium to potential acid load. Our results suggest a joint control on emissions of multiple acid precursors from urban areas in southern China. PMID:26211880

Spatial boundary of urban 'acid islands' in southern China.

PubMed

Du, E; de Vries, W; Liu, X; Fang, J; Galloway, J N; Jiang, Y

2015-07-27

Elevated emissions of sulfur dioxide, nitrogen oxides and ammonia in China have resulted in high levels of sulfur and nitrogen deposition, being contributors to soil acidification, especially in and near large cities. However, knowledge gaps still exist in the way that large cities shape spatial patterns of acid deposition. Here, we assessed the patterns of pH, sulfate, nitrate and ammonium in bulk precipitation and throughfall in southern China's forests by synthesizing data from published literature. Concentrations and fluxes of sulfate, nitrate and ammonium in bulk precipitation and throughfall exhibited a power-law increase with a closer distance to the nearest large cities, and accordingly pH showed a logarithmic decline. Our findings indicate the occurrence of urban 'acid islands' with a critical radius of approximately 70 km in southern China, receiving potential acid loads of more than 2 keq ha(-1) yr(-1). These urban acid islands covered an area of 0.70 million km(2), accounting for nearly 30% of the land area in southern China. Despite a significant capacity to neutralize acids in precipitation, our analysis highlights a substantial contribution of ammonium to potential acid load. Our results suggest a joint control on emissions of multiple acid precursors from urban areas in southern China.

Modelling NO2 concentrations at the street level in the GAINS integrated assessment model: projections under current legislation

NASA Astrophysics Data System (ADS)

Kiesewetter, G.; Borken-Kleefeld, J.; Schöpp, W.; Heyes, C.; Thunis, P.; Bessagnet, B.; Gsella, A.; Amann, M.

2013-08-01

NO2 concentrations at the street level are a major concern for urban air quality in Europe and have been regulated under the EU Thematic Strategy on Air Pollution. Despite the legal requirements, limit values are exceeded at many monitoring stations with little or no improvement during recent years. In order to assess the effects of future emission control regulations on roadside NO2 concentrations, a downscaling module has been implemented in the GAINS integrated assessment model. The module follows a hybrid approach based on atmospheric dispersion calculations and observations from the AirBase European air quality data base that are used to estimate site-specific parameters. Pollutant concentrations at every monitoring site with sufficient data coverage are disaggregated into contributions from regional background, urban increment, and local roadside increment. The future evolution of each contribution is assessed with a model of the appropriate scale - 28 × 28 km grid based on the EMEP Model for the regional background, 7 × 7 km urban increment based on the CHIMERE Chemistry Transport Model, and a chemical box model for the roadside increment. Thus, different emission scenarios and control options for long-range transport, regional and local emissions can be analysed. Observed concentrations and historical trends are well captured, in particular the differing NO2 and total NOx = NO + NO2 trends. Altogether, more than 1950 air quality monitoring stations in the EU are covered by the model, including more than 400 traffic stations and 70% of the critical stations. Together with its well-established bottom-up emission and dispersion calculation scheme, GAINS is thus able to bridge the scales from European-wide policies to impacts in street canyons. As an application of the model, we assess the evolution of attainment of NO2 limit values under current legislation until 2030. Strong improvements are expected with the introduction of the Euro 6 emission standard for light duty vehicles; however, for some major European cities, further measures may be required, in particular if aiming to achieve compliance at an earlier time.

Modelling NO2 concentrations at the street level in the GAINS integrated assessment model: projections under current legislation

NASA Astrophysics Data System (ADS)

Kiesewetter, G.; Borken-Kleefeld, J.; Schöpp, W.; Heyes, C.; Thunis, P.; Bessagnet, B.; Terrenoire, E.; Gsella, A.; Amann, M.

2014-01-01

NO2 concentrations at the street level are a major concern for urban air quality in Europe and have been regulated under the EU Thematic Strategy on Air Pollution. Despite the legal requirements, limit values are exceeded at many monitoring stations with little or no improvement in recent years. In order to assess the effects of future emission control regulations on roadside NO2 concentrations, a downscaling module has been implemented in the GAINS integrated assessment model. The module follows a hybrid approach based on atmospheric dispersion calculations and observations from the AirBase European air quality database that are used to estimate site-specific parameters. Pollutant concentrations at every monitoring site with sufficient data coverage are disaggregated into contributions from regional background, urban increment, and local roadside increment. The future evolution of each contribution is assessed with a model of the appropriate scale: 28 × 28 km grid based on the EMEP Model for the regional background, 7 × 7 km urban increment based on the CHIMERE Chemistry Transport Model, and a chemical box model for the roadside increment. Thus, different emission scenarios and control options for long-range transport as well as regional and local emissions can be analysed. Observed concentrations and historical trends are well captured, in particular the differing NO2 and total NOx = NO + NO2 trends. Altogether, more than 1950 air quality monitoring stations in the EU are covered by the model, including more than 400 traffic stations and 70% of the critical stations. Together with its well-established bottom-up emission and dispersion calculation scheme, GAINS is thus able to bridge the scales from European-wide policies to impacts in street canyons. As an application of the model, we assess the evolution of attainment of NO2 limit values under current legislation until 2030. Strong improvements are expected with the introduction of the Euro 6 emission standard for light duty vehicles; however, for some major European cities, further measures may be required, in particular if aiming to achieve compliance at an earlier time.

Volatile chemical products emerging as largest petrochemical source of urban organic emissions

NASA Astrophysics Data System (ADS)

McDonald, Brian C.; de Gouw, Joost A.; Gilman, Jessica B.; Jathar, Shantanu H.; Akherati, Ali; Cappa, Christopher D.; Jimenez, Jose L.; Lee-Taylor, Julia; Hayes, Patrick L.; McKeen, Stuart A.; Cui, Yu Yan; Kim, Si-Wan; Gentner, Drew R.; Isaacman-VanWertz, Gabriel; Goldstein, Allen H.; Harley, Robert A.; Frost, Gregory J.; Roberts, James M.; Ryerson, Thomas B.; Trainer, Michael

2018-02-01

A gap in emission inventories of urban volatile organic compound (VOC) sources, which contribute to regional ozone and aerosol burdens, has increased as transportation emissions in the United States and Europe have declined rapidly. A detailed mass balance demonstrates that the use of volatile chemical products (VCPs)—including pesticides, coatings, printing inks, adhesives, cleaning agents, and personal care products—now constitutes half of fossil fuel VOC emissions in industrialized cities. The high fraction of VCP emissions is consistent with observed urban outdoor and indoor air measurements. We show that human exposure to carbonaceous aerosols of fossil origin is transitioning away from transportation-related sources and toward VCPs. Existing U.S. regulations on VCPs emphasize mitigating ozone and air toxics, but they currently exempt many chemicals that lead to secondary organic aerosols.

China's growing CO2 emissions--a race between increasing consumption and efficiency gains.

PubMed

Peters, Glen P; Weber, Christopher L; Guan, Dabo; Hubacek, Klaus

2007-09-01

China's rapidly growing economy and energy consumption are creating serious environmental problems on both local and global scales. Understanding the key drivers behind China's growing energy consumption and the associated CO2 emissions is critical for the development of global climate policies and provides insight into how other emerging economies may develop a low emissions future. Using recently released Chinese economic input-output data and structural decomposition analysis we analyze how changes in China's technology, economic structure, urbanization, and lifestyles affect CO2 emissions. We find that infrastructure construction and urban household consumption, both in turn driven by urbanization and lifestyle changes, have outpaced efficiency improvements in the growth of CO2 emissions. Net trade had a small effect on total emissions due to equal, but significant, growth in emissions from the production of exports and emissions avoided by imports. Technology and efficiency improvements have only partially offset consumption growth, but there remains considerable untapped potential to reduce emissions by improving both production and consumption systems. As China continues to rapidly develop there is an opportunity to further implement and extend policies, such as the Circular Economy, that will help China avoid the high emissions path taken by today's developed countries.

Overview of Megacity Air Pollutant Emissions and Impacts

NASA Astrophysics Data System (ADS)

Kolb, C. E.

2013-05-01

The urban metabolism that characterizes major cities consumes very large qualities of humanly produced and/or processed food, fuel, water, electricity, construction materials and manufactured goods, as well as, naturally provided sunlight, precipitation and atmospheric oxygen. The resulting urban respiration exhalations add large quantities of trace gas and particulate matter pollutants to urban atmospheres. Key classes of urban primary air pollutants and their sources will be reviewed and important secondary pollutants identified. The impacts of these pollutants on urban and downwind regional inhabitants, ecosystems, and climate will be discussed. Challenges in quantifying the temporally and spatially resolved urban air pollutant emissions and secondary pollutant production rates will be identified and possible measurement strategies evaluated.

Smart urban design to reduce transportation impact in city centers

NASA Astrophysics Data System (ADS)

Fezzai, Soufiane; Mazouz, Said; Ahriz, Atef

2018-05-01

Air pollution is one of the most serious problems facing human being; urban wastes are in first range of energy consumption and emission of greenhouse gasses. Transportation or car traffic is one of the most consumer sectors of fuel, and most pollutant. Reducing energy consumption in transportation and the emission of pollutant gasses becomes an important objective for urban designers; many solutions may be proposed to help solving this problem in future designs, but it depend on other factors in existing urban space especially in city centers characterized with high occupation density. In this paper we investigate traffic rate in the city center of the case study, looking for the causes of the high traffic using gate count method and estimating fuel consumption. We try to propose some design solutions to reduce distances so fuel consumption and emission of pollutant gasses. We use space syntax techniques to evaluate urban configuration and verify the proposed solutions.

A framework for emissions source apportionment in industrial areas: MM5/CALPUFF in a near-field application.

PubMed

Ghannam, K; El-Fadel, M

2013-02-01

This paper examines the relative source contribution to ground-level concentrations of carbon monoxide (CO), nitrogen dioxide (NO2), and PM10 (particulate matter with an aerodynamic diameter < 10 microm) in a coastal urban area due to emissions from an industrial complex with multiple stacks, quarrying activities, and a nearby highway. For this purpose, an inventory of CO, oxide of nitrogen (NO(x)), and PM10 emissions was coupled with the non-steady-state Mesoscale Model 5/California Puff Dispersion Modeling system to simulate individual source contributions under several spatial and temporal scales. As the contribution of a particular source to ground-level concentrations can be evaluated by simulating this single-source emissions or otherwise total emissions except that source, a set of emission sensitivity simulations was designed to examine if CALPUFF maintains a linear relationship between emission rates and predicted concentrations in cases where emitted plumes overlap and chemical transformations are simulated. Source apportionment revealed that ground-level releases (i.e., highway and quarries) extended over large areas dominated the contribution to exposure levels over elevated point sources, despite the fact that cumulative emissions from point sources are higher. Sensitivity analysis indicated that chemical transformations of NO(x) are insignificant, possibly due to short-range plume transport, with CALPUFF exhibiting a linear response to changes in emission rate. The current paper points to the significance of ground-level emissions in contributing to urban air pollution exposure and questions the viability of the prevailing paradigm of point-source emission reduction, especially that the incremental improvement in air quality associated with this common abatement strategy may not accomplish the desirable benefit in terms of lower exposure with costly emissions capping. The application of atmospheric dispersion models for source apportionment helps in identifying major contributors to regional air pollution. In industrial urban areas where multiple sources with different geometry contribute to emissions, ground-level releases extended over large areas such as roads and quarries often dominate the contribution to ground-level air pollution. Industrial emissions released at elevated stack heights may experience significant dilution, resulting in minor contribution to exposure at ground level. In such contexts, emission reduction, which is invariably the abatement strategy targeting industries at a significant investment in control equipment or process change, may result in minimal return on investment in terms of improvement in air quality at sensitive receptors.

Impact of biodiesel on regulated and unregulated emissions, and redox and proinflammatory properties of PM emitted from heavy-duty vehicles.

PubMed

Karavalakis, Georgios; Gysel, Nicholas; Schmitz, Debra A; Cho, Arthur K; Sioutas, Constantinos; Schauer, James J; Cocker, David R; Durbin, Thomas D

2017-04-15

The emissions and the potential health effects of particulate matter (PM) were assessed from two heavy-duty trucks with and without emission control aftertreatment systems when operating on CARB ultra-low sulfur diesel (ULSD) and three different biodiesel blends. The CARB ULSD was blended with soy-based biodiesel, animal fat biodiesel, and waste cooking oil biodiesel at 50vol%. Testing was conducted over the EPA Urban Dynamometer Driving Schedule (UDDS) in triplicate for both trucks. The aftertreatment controls effectively decreased PM mass and number emissions, as well as the polycyclic aromatic hydrocarbons (PAHs) compared to the uncontrolled truck. Emissions of nitrogen oxides (NO x ) exhibited increases with the biodiesel blends, showing some feedstock dependency for the controlled truck. The oxidative potential of the emitted PM, measured by means of the dithiothreitol (DTT) assay, showed reductions with the use of biodiesel blends relative to CARB ULSD for the uncontrolled truck. Overall, the cellular responses to the particles from each fuel were reflective of the chemical content, i.e., particles from CARB ULSD were the most reactive and exhibited the highest cellular responses. Copyright © 2017 Elsevier B.V. All rights reserved.

Assessment on the Benefits from Energy Structure Optimization and Coal-fired Emission Control in Beijing: 1998-2013

NASA Astrophysics Data System (ADS)

Zong, Y.; He, K.; Zhang, Q.; Hong, C.

2016-12-01

Coal has long been an important energy type of Beijing's energy consumption. Since 1998, to improve urban air quality, Beijing has vigorously promoted the structure optimization of energy consumption. Primary measures included the implementation of strict emission standards for coal-fired power plant boilers, subsidized replacement and after-treatment retrofit of coal-fired boilers, the mandatory application of low-sulfur coal, and the accelerated use of natural gas, imported electricity and other clean energy. This work attempts to assess the emission reduction benefits on measures of three sectors, including replacing with clean energy and application of end-of-pipe control technologies in power plants, comprehensive control on coal-fired boilers and residential heating renovation. This study employs the model of Multi-resolution Emission Inventory for China (MEIC) to quantify emission reductions from upfront measures. These control measures have effectively reduced local emissions of major air pollutants in Beijing. The total emissions of PM2.5, PM10, SO2 and NOX from power plants in Beijing are estimated to have reduced 14.5 kt, 23.7 kt, 45.0 kt and 7.6 kt from 1998 to 2013, representing reductions of 86%, 87%, 85% and 16%, respectively. Totally, 14.3 kt, 24.0 kt, 136 kt and 48.7kt of PM2.5, PM10, SO2 and NOX emissions have been mitigated due to the comprehensive control measures on coal-fired boilers from 1998 to 2013. Residential heating renovation projects by replacing coal with electricity in Beijing's conventional old house areas contribute to emission reductions of 630 t, 870 t, 2070 t and 790 t for PM2.5, PM10, SO2 and NOX, respectively.

Synergies and trade-offs between energy-efficient urbanization and health

NASA Astrophysics Data System (ADS)

Ahmad, Sohail; Pachauri, Shonali; Creutzig, Felix

2017-11-01

Energy-efficient urbanization and public health pose major development challenges for India. While both issues are intensively studied, their interaction is not well understood. Here we explore the relationship between urban infrastructures, public health, and household-related emissions, identifying potential synergies and trade-offs of specific interventions by analyzing nationally representative household surveys from 2005 and 2012. Our analysis confirms previous characterizations of the environmental-health transition, but also points to an important role of energy use and urbanization as modifiers of this transition. We find that non-motorized transport may prove a sweet spot for development, as its use is associated with lower emissions and better public health in cities. Urbanization and improved access to basic services correlate with lower short-term morbidity (STM), such as fever, cough and diarrhea. Our analysis suggests that a 10% increase in urbanization from current levels and concurrent improvement in access to modern cooking and clean water could lower STM for 2.4 million people. This would be associated with a modest increase in electricity related emissions of 84 ktCO2e annually. Promoting energy-efficient mobility systems, for instance by a 10% increase in bicycling, could lower chronic conditions like diabetes and cardio-vascular diseases for 0.3 million people while also abating emissions. These findings provide empirical evidence to validate that energy-efficient and sustainable urbanization can address both public health and climate change challenges simultaneously.

Changing Urban Carbon Metabolism over Time: Historical Trajectory and Future Pathway.

PubMed

Chen, Shaoqing; Chen, Bin

2017-07-05

Cities are expected to play a major role in carbon emissions mitigation. A key step in decoupling urban economy from carbon emissions is to understand the full impact of socioeconomic development on urban metabolism over time. Herein, we establish a system-based framework for modeling the variation of urban carbon metabolism through time by integrating a metabolic flow inventory, input-output model, and network analysis. Using Beijing as a case study, we track the historical trajectory of carbon flows embodied in urban final consumption over 1985-2012. We find that while the tendency of increase in direct carbon emission continues within this time frame, consumption-based carbon footprint might have peaked around 2010. Significant transitions in emission intensity and roles sectors play in transferring carbon over the period are important signs of decoupling urban development from carbonization. Our further analysis of driving factors reveals a strong competition between efficiency gains and consumption level rise, showing a cumulative contribution of -584% and 494% to total carbon footprint, respectively. Projection into a future pathway suggests there is still a great potential for carbon mitigation for the city, but a strong mitigation plan is required to achieve such decarbonization before 2030. By bridging temporal metabolic model and socioeconomic planning, this framework fills one of the main gaps between monitoring of urban metabolism and design of a low-carbon economy.

Cities, traffic, and CO 2: A multidecadal assessment of trends, drivers, and scaling relationships

DOE PAGES

Gately, Conor K.; Hutyra, Lucy R.; Sue Wing, Ian

2015-04-06

Emissions of CO 2 from road vehicles were 1.57 billion metric tons in 2012, accounting for 28% of US fossil fuel CO 2 emissions, but the spatial distributions of these emissions are highly uncertain. We develop a new emissions inventory, the Database of Road Transportation Emissions (DARTE), which estimates CO 2 emitted by US road transport at a resolution of 1 km annually for 1980-2012. DARTE reveals that urban areas are responsible for 80% of on-road emissions growth since 1980 and for 63% of total 2012 emissions. We observe nonlinearities between CO 2 emissions and population density at broad spatial/temporalmore » scales, with total on-road CO 2 increasing nonlinearly with population density, rapidly up to 1,650 persons per square kilometer and slowly thereafter. Per capita emissions decline as density rises, but at markedly varying rates depending on existing densities. Here, we make use of DARTE's bottom-up construction to highlight the biases associated with the common practice of using population as a linear proxy for disaggregating national- or state-scale emissions. Comparing DARTE with existing downscaled inventories, we find biases of 100% or more in the spatial distribution of urban and rural emissions, largely driven by mismatches between inventory downscaling proxies and the actual spatial patterns of vehicle activity at urban scales. Here, given cities' dual importance as sources of CO 2 and an emerging nexus of climate mitigation initiatives, high-resolution estimates such as DARTE are critical both for accurately quantifying surface carbon fluxes and for verifying the effectiveness of emissions mitigation efforts at urban scales.« less

The influence of model resolution on ozone in industrial volatile organic compound plumes.

PubMed

Henderson, Barron H; Jeffries, Harvey E; Kim, Byeong-Uk; Vizuete, William G

2010-09-01

Regions with concentrated petrochemical industrial activity (e.g., Houston or Baton Rouge) frequently experience large, localized releases of volatile organic compounds (VOCs). Aircraft measurements suggest these released VOCs create plumes with ozone (O3) production rates 2-5 times higher than typical urban conditions. Modeling studies found that simulating high O3 productions requires superfine (1-km) horizontal grid cell size. Compared with fine modeling (4-kmin), the superfine resolution increases the peak O3 concentration by as much as 46%. To understand this drastic O3 change, this study quantifies model processes for O3 and "odd oxygen" (Ox) in both resolutions. For the entire plume, the superfine resolution increases the maximum O3 concentration 3% but only decreases the maximum Ox concentration 0.2%. The two grid sizes produce approximately equal Ox mass but by different reaction pathways. Derived sensitivity to oxides of nitrogen (NOx) and VOC emissions suggests resolution-specific sensitivity to NOx and VOC emissions. Different sensitivity to emissions will result in different O3 responses to subsequently encountered emissions (within the city or downwind). Sensitivity of O3 to emission changes also results in different simulated O3 responses to the same control strategies. Sensitivity of O3 to NOx and VOC emission changes is attributed to finer resolved Eulerian grid and finer resolved NOx emissions. Urban NOx concentration gradients are often caused by roadway mobile sources that would not typically be addressed with Plume-in-Grid models. This study shows that grid cell size (an artifact of modeling) influences simulated control strategies and could bias regulatory decisions. Understanding the dynamics of VOC plume dependence on grid size is the first step toward providing more detailed guidance for resolution. These results underscore VOC and NOx resolution interdependencies best addressed by finer resolution. On the basis of these results, the authors suggest a need for quantitative metrics for horizontal grid resolution in future model guidance.

Inverse modeling of fossil fuel CO2 emissions at urban scale using OCO-2 retrievals of total column CO2

NASA Astrophysics Data System (ADS)

Ye, X.; Lauvaux, T.; Kort, E. A.; Lin, J. C.; Oda, T.; Yang, E.; Wu, D.

2016-12-01

Rapid economic development has given rise to a steady increase of global carbon emissions, which have accumulated in the atmosphere for the past 200 years. Urbanization has concentrated about 70% of the global fossil-fuel CO2 emissions in large metropolitan areas distributed around the world, which represents the most significant anthropogenic contribution to climate change. However, highly uncertain quantifications of urban CO2 emissions are commonplace for numerous cities because of poorly-documented inventories of energy consumption. Therefore, accurate estimates of carbon emissions from global observing systems are a necessity if mitigation strategies are meant to be implemented at global scales. Space-based observations of total column averaged CO2 concentration (XCO2) provide a very promising and powerful tool to quantify urban CO2 fluxes. For the first time, measurements from the Orbiting Carbon Observatory 2 (OCO-2) mission are assimilated in a high resolution inverse modeling system to quantify fossil-fuel CO2 emissions of multiple cities around the globe. The Open-source Data Inventory for Anthropogenic CO2 (ODIAC) emission inventory is employed as a first guess, while the atmospheric transport is simulated using the WRF-Chem model at 1-km resolution. Emission detection and quantification is performed with an Ensemble Kalman Filter method. We demonstrate here the potential of the inverse approach for assimilating thousands of OCO-2 retrievals along tracks near metropolitan areas. We present the detection potential of the system with real-case applications near power plants and present inverse emissions using actual OCO-2 measurements on various urban landscapes. Finally, we will discuss the potential of OCO-2-like satellite instruments for monitoring temporal variations of fossil-fuel CO2 emissions over multiple years, which can provide valuable insights for future satellite observation strategies.

Urban stress-induced biogenic VOC emissions impact secondary aerosol formation in Beijing

NASA Astrophysics Data System (ADS)

Ghirardo, A.; Xie, J.; Zheng, X.; Wang, Y.; Grote, R.; Block, K.; Wildt, J.; Mentel, T.; Kiendler-Scharr, A.; Hallquist, M.; Butterbach-Bahl, K.; Schnitzler, J.-P.

2015-08-01

Trees can significantly impact the urban air chemistry by the uptake and emission of reactive biogenic volatile organic compounds (BVOCs), which are involved in ozone and particle formation. Here we present the emission potentials of "constitutive" (cBVOCs) and "stress-induced" BVOCs (sBVOCs) from the dominant broadleaf woody plant species in the megacity of Beijing. Based on an inventory of BVOC emissions and the tree census, we assessed the potential impact of BVOCs on secondary particulate matter formation in 2005 and 2010, i.e., before and after realizing the large tree-planting program for the 2008 Olympic Games. We found that sBVOCs, such as fatty acid derivatives, benzenoids and sesquiterpenes, constituted a significant fraction (∼ 15 %) of the total annual BVOC emissions, and we estimated that the overall annual BVOC budget may have doubled from ∼ 3.6 × 109 g C year-1 in 2005 to ∼ 7.1 × 109 g C year-1 in 2010 due to the increase in urban greens, while at the same time, the emission of anthropogenic VOCs (AVOCs) could be lowered by 24 %. Based on our BVOC emission assessment, we estimated the biological impact on SOA mass formation in Beijing. Compared to AVOCs, the contribution of biogenic precursors (2-5 %) for secondary particulate matter in Beijing was low. However, sBVOCs can significantly contribute (∼ 40 %) to the formation of total secondary organic aerosol (SOA) from biogenic sources; apparently, their annual emission increased from 1.05 μg m-3 in 2005 to 2.05 μg m-3 in 2010. This study demonstrates that biogenic and, in particular, sBVOC emissions contribute to SOA formation in megacities. However, the main problems regarding air quality in Beijing still originate from anthropogenic activities. Nevertheless, the present survey suggests that in urban plantation programs, the selection of plant species with low cBVOC and sBVOC emission potentials have some possible beneficial effects on urban air quality.

The avoidable health effects of air pollution in three Latin American cities: Santiago, São Paulo, and Mexico City.

PubMed

Bell, Michelle L; Davis, Devra L; Gouveia, Nelson; Borja-Aburto, Víctor H; Cifuentes, Luis A

2006-03-01

Urban centers in Latin American often face high levels of air pollution as a result of economic and industrial growth. Decisions with regard to industry, transportation, and development will affect air pollution and health both in the short term and in the far future through climate change. We investigated the pollution health consequences of modest changes in fossil fuel use for three case study cities in Latin American: Mexico City, Mexico; Santiago, Chile; and São Paulo, Brazil. Annual levels of ozone and particulate matter were estimated from 2000 to 2020 for two emissions scenarios: (1) business-as-usual based on current emissions patterns and regulatory trends and (2) a control policy aimed at lowering air pollution emissions. The resulting air pollution levels were linked to health endpoints through concentration-response functions derived from epidemiological studies, using local studies where available. Results indicate that the air pollution control policy would have vast health benefits for each of the three cities, averting numerous adverse health outcomes including over 156,000 deaths, 4 million asthma attacks, 300,000 children's medical visits, and almost 48,000 cases of chronic bronchitis in the three cities over the 20-year period. The economic value of the avoided health impacts is roughly 21 to 165 billion Dollars (US). Sensitivity analysis shows that the control policy yields significant health and economic benefits even with relaxed assumptions with regard to population growth, pollutant concentrations for the control policy, concentration-response functions, and economic value of health outcomes. This research demonstrates the health and economic burden from air pollution in Latin American urban centers and the magnitude of health benefits from control policies.

Integrating remote sensing and local vegetation information for a high-resolution biogenic emissions inventory--application to an urbanized, semiarid region.

PubMed

Diem, J E; Comrie, A C

2000-11-01

This paper presents a methodology for the development of a high-resolution (30-m), standardized biogenic volatile organic compound (BVOC) emissions inventory and a subsequent application of the methodology to Tucson, AZ. The region's heterogeneous vegetation cover cannot be modeled accurately with low-resolution (e.g., 1-km) land cover and vegetation information. Instead, local vegetation data are used in conjunction with multispectral satellite data to generate a detailed vegetation-based land-cover database of the region. A high-resolution emissions inventory is assembled by associating the vegetation data with appropriate emissions factors. The inventory reveals a substantial variation in BVOC emissions across the region, resulting from the region's diversity of both native and exotic vegetation. The importance of BVOC emissions from forest lands, desert lands, and the urban forest changes according to regional, metropolitan, and urban scales. Within the entire Tucson region, the average isoprene, monoterpene, and OVOC fluxes observed were 454, 248, and 91 micrograms/m2/hr, respectively, with forest and desert lands emitting nearly all of the BVOCs. Within the metropolitan area, which does not include the forest lands, the average fluxes were 323, 181, and 70 micrograms/m2/hr, respectively. Within the urban area, the average fluxes were 801, 100, and 100 micrograms/m2/hr, respectively, with exotic trees such as eucalyptus, pine, and palm emitting most of the urban BVOCs. The methods presented in this paper can be modified to create detailed, standardized BVOC emissions inventories for other regions, especially those with spatially complex vegetation patterns.

Transport and public health in China: the road to a healthy future

PubMed Central

Jiang, Baoguo; Liang, Song; Peng, Zhong-Ren; Cong, Haozhe; Levy, Morgan; Cheng, Qu; Wang, Tianbing; Remais, Justin

2017-01-01

Transportation-related risk factors are a major source of morbidity and mortality in China, where expansion of road networks and surges in personal vehicle ownership are having profound effects on public health. Road traffic injuries and fatalities have increased alongside motorized transport in China, and accident injury risk is aggravated by inadequate emergency response systems and trauma care. National air quality standards and emission control technologies are having a positive effect, yet persistent air pollution is increasingly attributable to a growing and outdated vehicle fleet, and famously congested roads. Urban design favors motorized transport, and physical activity and its associated health benefits are hindered by poor urban infrastructure. Transport emissions of greenhouse gases contribute substantially to regional and global climate change, which compound public health risks from multiple factors. Despite these complex challenges, technological advances and innovations in planning and policy stand to make China a leader in sustainable, healthy transportation. PMID:29047445

Carbon emission and sequestration of urban turfgrass systems in Hong Kong.

PubMed

Kong, Ling; Shi, Zhengjun; Chu, L M

2014-03-01

Climate change is more than just a global issue. Locally released carbon dioxide may lead to a rise in global ambient temperature and influence the surrounding climate. Urban greenery may mitigate this as they can remove carbon dioxide by storing carbon in substrates and vegetation. On the other hand, urban greenery systems which are under intense management and maintenance may contribute to the emission of carbon dioxide or other greenhouse gases. The impact of urban greenery on carbon balance in major metropolitan areas thus remains controversial. We investigated the carbon footprints of urban turf operation and maintenance by conducting a research questionnaire on different Hong Kong turfs in 2012, and showed that turf maintenance contributed 0.17 to 0.63 kg Ce m(-2)y(-1) to carbon emissions. We also determined the carbon storage of turfs at 0.05 to 0.21 kg C m(-2) for aboveground grass biomass and 1.26 to 4.89 kg C m(-2) for soils (to 15 cm depth). We estimated that the carbon sink capacity of turfs could be offset by carbon emissions in 5-24 years under current management patterns, shifting from carbon sink to carbon source. Our study suggested that maintenance management played a key role in the carbon budget and footprint of urban greeneries. The environmental impact of turfgrass systems can be optimized by shifting away from empirically designed maintenance schedules towards rational ones based on carbon sink and emission principles. Copyright © 2014 Elsevier B.V. All rights reserved.

Emission of heavy metals from an urban catchment into receiving water and possibility of its limitation on the example of Lodz city.

PubMed

Sakson, Grazyna; Brzezinska, Agnieszka; Zawilski, Marek

2018-04-14

Heavy metals are among the priority pollutants which may have toxic effects on receiving water bodies. They are detected in most of samples of stormwater runoff, but the concentrations are very variable. This paper presents results of study on the amount of heavy metals discharged from urban catchment in Lodz (Poland) in 2011-2013. The research was carried out to identify the most important sources of their emission and to assess the threats to receiving water quality and opportunities of their limitation. The city is equipped with a combined sewerage in the center with 18 combined sewer overflows and with separate system in other parts. Stormwater and wastewater from both systems are discharged into 18 small urban rivers. There is a need of restoration of water bodies in the city. Research results indicate that the main issue is high emission of heavy metals, especially zinc and copper, contained in stormwater. Annual mass loads (g/ha/year) from separate system were 1629 for Zn and 305 for Cu. It was estimated that about 48% of the annual load of Zn, 38% of Cu, 61% of Pb, and 40% of Cd discharged into receiving water came from separate system, respectively 4% of Zn and Cu, 10% of Pb and 11% of Cd from CSOs, and the remaining part from wastewater treatment plant. Effective reduction of heavy metals loads discharged into receiving water requires knowledge of sources and emissions for each catchment. Obtained data may indicate the need to apply centralized solution or decentralized by source control.

Historical evaluation of vehicle emission control in Guangzhou based on a multi-year emission inventory

NASA Astrophysics Data System (ADS)

Zhang, Shaojun; Wu, Ye; Liu, Huan; Wu, Xiaomeng; Zhou, Yu; Yao, Zhiliang; Fu, Lixin; He, Kebin; Hao, Jiming

2013-09-01

The Guangzhou government adopted many vehicle emission control policies and strategies during the five-year preparation (2005-2009) to host the 2010 Asian Games. This study established a multi-year emission inventory for vehicles in Guangzhou during 2005-2009 and estimated the uncertainty in total vehicle emissions by taking the assumed uncertainties in fleet-average emission factors and annual mileage into account. In 2009, the estimated total vehicle emissions in Guangzhou were 313 000 (242 000-387 000) tons of CO, 60 900 (54 000-70 200) tons of THC, 65 600 (56 800-74 100) tons of NOx and 2740 (2100-3400) tons of PM10. Vehicle emissions within the urban area of Guangzhou were estimated to be responsible for ˜40% of total gaseous pollutants and ˜25% of total PM10 in the entire city. Although vehicle use intensity increased rapidly in Guangzhou during 2005-2009, vehicle emissions were estimated to have been reduced by 12% for CO, 21% for THC and 20% for PM10 relative to those in 2005. NOx emissions were estimated to have remained almost constant during this period. Compared to the "without control" scenario, 19% (15%-23%) of CO, 20% (18%-23%) of THC, 9% (8%-10%) of NOx and 16% (12%-20%) of PM10 were estimated to have been mitigated from a combination of the implementation of Euro III standards for light-duty vehicles (LDVs) and heavy-duty diesel vehicles and improvement of fuel quality. This study also evaluated several enhanced vehicle emission control actions taken recently. For example, the enhanced I/M program for LDVs was estimated to reduce 11% (9%-14%) of CO, 9% (8%-10%) of THC and 2% (2%-3%) of NOx relative to total vehicle emissions in 2009. Total emission reductions by temporary traffic controls for the Asian Games were estimated equivalent to 9% (7%-11%) of CO, 9% (8%-10%) of THC, 5% (5%-6%) of NOx and 10% (8%-13%) of PM10 estimated total vehicle emissions in 2009. Those controls are essential to further vehicle emission mitigation in Guangzhou required by the new National Ambient Air Quality Standards.

Near-source mobile methane emission estimates using EPA Method33a and a novel probabilistic approach as a basis for leak quantification in urban areas

NASA Astrophysics Data System (ADS)

Albertson, J. D.

2015-12-01

Methane emissions from underground pipeline leaks remain an ongoing issue in the development of accurate methane emission inventories for the natural gas supply chain. Application of mobile methods during routine street surveys would help address this issue, but there are large uncertainties in current approaches. In this paper, we describe results from a series of near-source (< 30 m) controlled methane releases where an instrumented van was used to measure methane concentrations during both fixed location sampling and during mobile traverses immediately downwind of the source. The measurements were used to evaluate the application of EPA Method 33A for estimating methane emissions downwind of a source and also to test the application of a new probabilistic approach for estimating emission rates from mobile traverse data.

Influences of natural emission sources (wildfires and Saharan dust) on the urban organic aerosol in Barcelona (Western Mediterranean Basis) during a PM event.

PubMed

van Drooge, Barend L; Lopez, Jordi F; Grimalt, Joan O

2012-11-01

The urban air quality in Barcelona in the Western Mediterranean Basin is characterized by overall high particulate matter (PM) concentrations, due to intensive local anthropogenic emissions and specific meteorological conditions. Moreover, on several days, especially in summer, natural PM sources, such as long-range transported Saharan dust from Northern Africa or wildfires on the Iberian Peninsula and around the Mediterranean Basin, may influence the levels and composition of the organic aerosol. In the second half of July 2009, daily collected PM(10) filter samples in an urban background site in Barcelona were analyzed on organic tracer compounds representing several emission sources. During this period, an important PM peak event was observed. Individual organic compound concentrations increased two to five times during this event. Although highest increase was observed for the organic tracer of biomass burning, the contribution to the organic aerosol was estimated to be around 6 %. Organic tracers that could be related to Saharan dust showed no correlation with the PM and OC levels, while this was the case for those related to fossil fuel combustion from traffic emissions. Moreover, a change in the meteorological conditions gave way to an overall increase of the urban background contamination. Long-range atmospheric transport of organic compounds from primary emissions sources (i.e., wildfires and Saharan dust) has a relatively moderate impact on the organic aerosol in an urban area where the local emissions are dominating.

Mapping CO2 emission in highly urbanized region using standardized microbial respiration approach

NASA Astrophysics Data System (ADS)

Vasenev, V. I.; Stoorvogel, J. J.; Ananyeva, N. D.

2012-12-01

Urbanization is a major recent land-use change pathway. Land conversion to urban has a tremendous and still unclear effect on soil cover and functions. Urban soil can act as a carbon source, although its potential for CO2 emission is also very high. The main challenge in analysis and mapping soil organic carbon (SOC) in urban environment is its high spatial heterogeneity and temporal dynamics. The urban environment provides a number of specific features and processes that influence soil formation and functioning and results in a unique spatial variability of carbon stocks and fluxes at short distance. Soil sealing, functional zoning, settlement age and size are the predominant factors, distinguishing heterogeneity of urban soil carbon. The combination of these factors creates a great amount of contrast clusters with abrupt borders, which is very difficult to consider in regional assessment and mapping of SOC stocks and soil CO2 emission. Most of the existing approaches to measure CO2 emission in field conditions (eddy-covariance, soil chambers) are very sensitive to soil moisture and temperature conditions. They require long-term sampling set during the season in order to obtain relevant results. This makes them inapplicable for the analysis of CO2 emission spatial variability at the regional scale. Soil respiration (SR) measurement in standardized lab conditions enables to overcome this difficulty. SR is predominant outgoing carbon flux, including autotrophic respiration of plant roots and heterotrophic respiration of soil microorganisms. Microbiota is responsible for 50-80% of total soil carbon outflow. Microbial respiration (MR) approach provides an integral CO2 emission results, characterizing microbe CO2 production in optimal conditions and thus independent from initial difference in soil temperature and moisture. The current study aimed to combine digital soil mapping (DSM) techniques with standardized microbial respiration approach in order to analyse and map CO2 emission and its spatial variability in highly urbanized Moscow region. Moscow region with its variability of bioclimatic conditions and high urbanization level (10 % from the total area) was chosen as an interesting case study. Random soil sampling in different soil zones (4) and land-use types (3 non-urban and 3 urban) was organized in Moscow region in 2010-2011 (n=242). Both topsoil (0-10 cm) and subsoil (10-150 cm) were included. MR for each point was analysed using standardized microbial (basal) respiration approach, including the following stages: 1) air dried soil samples were moisturised up to 55% water content and preincubated (7 days, 22° C) in a plastic bag with air exchange; 2) soil MR (in μg CO2-C g-1) was measured as the rate of CO2 production (22° C, 24 h) after incubating 2g soil with 0.2 μl distilled water; 3) the MR results were used to estimate CO2 emission (kg C m-2 yr-1). Point MR and CO2 emission results obtained were extrapolated for the Moscow region area using regression model. As a result, two separate CO2 maps for topsoil and subsoil were created. High spatial variability was demonstrated especially for the urban areas. Thus standardized MR approach combined with DSM techniques provided a unique opportunity for spatial analysis of soil carbon temporal dynamics at the regional scale.

Assessment of Co-benefits of vehicle emission reduction measures for 2015-2020 in the Pearl River Delta region, China.

PubMed

Liu, Yong-Hong; Liao, Wen-Yuan; Lin, Xiao-Fang; Li, Li; Zeng, Xue-Lan

2017-04-01

Vehicle emissions have become one of the key factors affecting the urban air quality and climate change in the Pearl River Delta (PRD) region, so it is important to design policies of emission reduction based on quantitative Co-benefits for air pollutants and greenhouse gas (GHG). Emissions of air pollutants and GHG by 2020 was predicted firstly based on the no-control scenario, and five vehicle emissions reduction scenarios were designed in view of the economy, technology and policy, whose emissions reduction were calculated. Then Co-benefits between air pollutants and GHG were quantitatively analyzed by the methods of coordinate system and cross-elasticity. Results show that the emissions reduction effects and the Co-benefits of different measures vary greatly in 2015-2020. If no control scheme was applied, most air pollutants and GHG would increase substantially by 20-64% by 2020, with the exception of CO, VOC and PM 2.5 . Different control measures had different reduction effects for single air pollutant and GHG. The worst reduction measure was Eliminating Motorcycles with average reducing rate 0.09% for air pollutants and GHG, while the rate from Updated Emission Standard was 41.74%. Eliminating Yellow-label Vehicle scenario had an obvious reduction effect for every single pollutant in the earlier years, but Co-benefits would descent to zero in later by 2020. From the perspective of emission reductions and co-control effect, Updated Emission Standard scenario was best for reducing air pollutants and GHG substantially (tanα=1.43 and Els=1.77). Copyright © 2016 Elsevier Ltd. All rights reserved.

Flux measurements of volatile organic compounds from an urban landscape

NASA Astrophysics Data System (ADS)

Velasco, E.; Lamb, B.; Pressley, S.; Allwine, E.; Westberg, H.; Jobson, B. T.; Alexander, M.; Prazeller, P.; Molina, L.; Molina, M.

2005-10-01

Direct measurements of volatile organic compound (VOC) emissions that include all sources in urban areas are a missing requirement to evaluate emission inventories and constrain current photochemical modelling practices. Here we demonstrate the use of micrometeorological techniques coupled with fast-response sensors to measure urban VOC fluxes from a neighbourhood of Mexico City, where the spatial variability of surface cover and roughness is high. Fluxes of olefins, methanol, acetone, toluene and C2-benzenes were measured and compared with the local gridded emissions inventory. VOC fluxes exhibited a clear diurnal pattern with a strong relationship to vehicular traffic. Recent photochemical modelling results suggest that VOC emissions are significantly underestimated in Mexico City, but for the olefin class, toluene, C2-benzenes, and acetone fluxes measured in this work, the results show general agreement with the gridded emissions inventory. While these measurements do not address the full suite of VOC emissions, the comparison with the inventory suggests that other explanations may be needed to explain the photochemical modelling results.

MOBILE EMISSIONS ASSESSMENT SYSTEM FOR URBAN AND REGIONAL EVALUATION

EPA Science Inventory

A working research model for Atlanta, GA has been developed by Georgia Tech, and is called the Mobile Emissions Assessment System for Urban and Regional Evaluation (MEASURE). The EPA Office of Research and Development has developed an additional implementation of the MEASURE res...

Modelling NOX concentrations through CFD-RANS in an urban hot-spot using high resolution traffic emissions and meteorology from a mesoscale model

NASA Astrophysics Data System (ADS)

Sanchez, Beatriz; Santiago, Jose Luis; Martilli, Alberto; Martin, Fernando; Borge, Rafael; Quaassdorff, Christina; de la Paz, David

2017-08-01

Air quality management requires more detailed studies about air pollution at urban and local scale over long periods of time. This work focuses on obtaining the spatial distribution of NOx concentration averaged over several days in a heavily trafficked urban area in Madrid (Spain) using a computational fluid dynamics (CFD) model. A methodology based on weighted average of CFD simulations is applied computing the time evolution of NOx dispersion as a sequence of steady-state scenarios taking into account the actual atmospheric conditions. The inputs of emissions are estimated from the traffic emission model and the meteorological information used is derived from a mesoscale model. Finally, the computed concentration map correlates well with 72 passive samplers deployed in the research area. This work reveals the potential of using urban mesoscale simulations together with detailed traffic emissions so as to provide accurate maps of pollutant concentration at microscale using CFD simulations.

Quantification of Methane Source Locations and Emissions in AN Urban Setting

NASA Astrophysics Data System (ADS)

Crosson, E.; Richardson, S.; Tan, S. M.; Whetstone, J.; Bova, T.; Prasad, K. R.; Davis, K. J.; Phillips, N. G.; Turnbull, J. C.; Shepson, P. B.; Cambaliza, M. L.

2011-12-01

The regulation of methane emissions from urban sources such as landfills and waste-water treatment facilities is currently a highly debated topic in the US and in Europe. This interest is fueled, in part, by recent measurements indicating that urban emissions are a significant source of Methane (CH4) and in fact may be substantially higher than current inventory estimates(1). As a result, developing methods for locating and quantifying emissions from urban methane sources is of great interest to industries such as landfill and wastewater treatment facility owners, watchdog groups, and the governmental agencies seeking to evaluate or enforce regulations. In an attempt to identify major methane source locations and emissions in Boston, Indianapolis, and the Bay Area, systematic measurements of CH4 concentrations and meteorology data were made at street level using a vehicle mounted cavity ringdown analyzer. A number of discrete sources were detected at concentration levels in excess of 15 times background levels. Using Gaussian plume models as well as tomographic techniques, methane source locations and emission rates will be presented. In addition, flux chamber measurements of discrete sources such as those found in natural gas leaks will also be presented. (1) Wunch, D., P.O. Wennberg, G.C. Toon, G. Keppel-Aleks, and Y.G. Yavin, Emissions of Greenhouse Gases from a North American Megacity, Geophysical Research Letters, Vol. 36, L15810, doi:10.1029/2009GL)39825, 2009.

Urban CO2 emissions metabolism: The Hestia Project

NASA Astrophysics Data System (ADS)

Gurney, K. R.; Razlivanov, I.; Zhou, Y.; Song, Y.

2011-12-01

A central expression of urban metabolism is the consumption of energy and the resulting environmental impact, particularly the emission of CO2 and other greenhouse gases. Quantification of energy and emissions has been performed for numerous cities but rarely has this been done in explicit space/time detail. Here, we present the Hestia Project, an effort aimed at building a high resolution (eg. building and road link-specific, hourly) fossil fuel CO2 emissions data product for the urban domain. A complete data product has been built for the city of Indianapolis and work is ongoing for the city of Los Angeles (Figure 1). The effort in Indianapolis is now part of a larger effort aimed at a convergent top-down/bottom-up assessment of greenhouse gas emissions, called INFLUX. Our urban-level quantification relies on a mixture of data and modeling structures. We start with the sector-specific Vulcan Project estimate at the mix of geocoded and county-wide levels. The Hestia aim is to distribute the Vulcan result in space and time. Two components take the majority of effort: buildings and onroad emissions. For the buildings, we utilize an energy building model which we constrain through lidar data, county assessor parcel data and GIS layers. For onroad emissions, we use a combination of traffic data and GIS road layers maintaining vehicle class information. Finally, all pointwise data in the Vulcan Project are transferred to our urban landscape and additional time distribution is performed. A key benefit of the approach taken in this study is the tracking and archiving of fuel and process-level detail (eg. combustion process, other pollutants), allowing for a more thorough understanding and analysis of energy throughputs in the urban environment. Next steps in this research from the metabolism perspective is to consider the carbon footprint of material goods and their lateral transfer in addition to the connection between electricity consumption and production.

Long-term trends in California mobile source emissions and ambient concentrations of black carbon and organic aerosol.

PubMed

McDonald, Brian C; Goldstein, Allen H; Harley, Robert A

2015-04-21

A fuel-based approach is used to assess long-term trends (1970-2010) in mobile source emissions of black carbon (BC) and organic aerosol (OA, including both primary emissions and secondary formation). The main focus of this analysis is the Los Angeles Basin, where a long record of measurements is available to infer trends in ambient concentrations of BC and organic carbon (OC), with OC used here as a proxy for OA. Mobile source emissions and ambient concentrations have decreased similarly, reflecting the importance of on- and off-road engines as sources of BC and OA in urban areas. In 1970, the on-road sector accounted for ∼90% of total mobile source emissions of BC and OA (primary + secondary). Over time, as on-road engine emissions have been controlled, the relative importance of off-road sources has grown. By 2010, off-road engines were estimated to account for 37 ± 20% and 45 ± 16% of total mobile source contributions to BC and OA, respectively, in the Los Angeles area. This study highlights both the success of efforts to control on-road emission sources, and the importance of considering off-road engine and other VOC source contributions when assessing long-term emission and ambient air quality trends.

Comparison of the predictions of two road dust emission models with the measurements of a mobile van

NASA Astrophysics Data System (ADS)

Kauhaniemi, M.; Stojiljkovic, A.; Pirjola, L.; Karppinen, A.; Härkönen, J.; Kupiainen, K.; Kangas, L.; Aarnio, M. A.; Omstedt, G.; Denby, B. R.; Kukkonen, J.

2014-09-01

The predictions of two road dust suspension emission models were compared with the on-site mobile measurements of suspension emission factors. Such a quantitative comparison has not previously been reported in the reviewed literature. The models used were the Nordic collaboration model NORTRIP (NOn-exhaust Road TRaffic Induced Particle emissions) and the Swedish-Finnish FORE model (Forecasting Of Road dust Emissions). These models describe particulate matter generated by the wear of road surface due to traction control methods and processes that control the suspension of road dust particles into the air. An experimental measurement campaign was conducted using a mobile laboratory called SNIFFER, along two selected road segments in central Helsinki in 2007 and 2008. The suspended PM10 concentration was measured behind the left rear tyre and the street background PM10 concentration in front of the van. Both models reproduced the measured seasonal variation of suspension emission factors fairly well during both years at both measurement sites. However, both models substantially under-predicted the measured emission values. The article illustrates the challenges in conducting road suspension measurements in densely trafficked urban conditions, and the numerous requirements for input data that are needed for accurately applying road suspension emission models.

Quantifying global fossil-fuel CO2 emissions: from OCO-2 to optimal observing designs

NASA Astrophysics Data System (ADS)

Ye, X.; Lauvaux, T.; Kort, E. A.; Oda, T.; Feng, S.; Lin, J. C.; Yang, E. G.; Wu, D.; Kuze, A.; Suto, H.; Eldering, A.

2017-12-01

Cities house more than half of the world's population and are responsible for more than 70% of the world anthropogenic CO2 emissions. Therefore, quantifications of emissions from major cities, which are only less than a hundred intense emitting spots across the globe, should allow us to monitor changes in global fossil-fuel CO2 emissions, in an independent, objective way. Satellite platforms provide favorable temporal and spatial coverage to collect urban CO2 data to quantify the anthropogenic contributions to the global carbon budget. We present here the optimal observation design for future NASA's OCO-2 and Japanese GOSAT missions, based on real-data (i.e. OCO-2) experiments and Observing System Simulation Experiments (OSSE's) to address different error components in the urban CO2 budget calculation. We identify the major sources of emission uncertainties for various types of cities with different ecosystems and geographical features, such as urban plumes over flat terrains, accumulated enhancements within basins, and complex weather regimes in coastal areas. Atmospheric transport errors were characterized under various meteorological conditions using the Weather Research and Forecasting (WRF) model at 1-km spatial resolution, coupled to the Open-source Data Inventory for Anthropogenic CO2 (ODIAC) emissions. We propose and discuss the optimized urban sampling strategies to address some difficulties from the seasonality in cloud cover and emissions, vegetation density in and around cities, and address the daytime sampling bias using prescribed diurnal cycles. These factors are combined in pseudo data experiments in which we evaluate the relative impact of uncertainties on inverse estimates of CO2 emissions for cities across latitudinal and climatological zones. We propose here several sampling strategies to minimize the uncertainties in target mode for tracking urban fossil-fuel CO2 emissions over the globe for future satellite missions, such as OCO-3 and future versions of GOSAT.

Edaphic factors controlling summer (rainy season) greenhouse gas emissions (CO2 and CH4) from semiarid mangrove soils (NE-Brazil).

PubMed

Nóbrega, Gabriel N; Ferreira, Tiago O; Siqueira Neto, M; Queiroz, Hermano M; Artur, Adriana G; Mendonça, Eduardo De S; Silva, Ebenezer De O; Otero, Xosé L

2016-01-15

The soil attributes controlling the CO2, and CH4 emissions were assessed in semiarid mangrove soils (NE-Brazil) under different anthropogenic activities. Soil samples were collected from different mangroves under different anthropogenic impacts, e.g., shrimp farming (Jaguaribe River); urban wastes (Cocó River) and a control site (Timonha River). The sites were characterized according to the sand content; physicochemical parameters (Eh and pH); total organic C; soil C stock (SCS) and equivalent SCS (SCSEQV); total P and N; dissolved organic C (DOC); and the degree of pyritization (DOP). The CO2 and CH4 fluxes from the soils were assessed using static closed chambers. Higher DOC and SCS and the lowest DOP promote greater CO2 emission. The CH4 flux was only observed at Jaguaribe which presented higher DOP, compared to that found in mangroves from humid tropical climates. Semiarid mangrove soils cannot be characterized as important greenhouse gas sources, compared to humid tropical mangroves.

Open Source Tools for Numerical Simulation of Urban Greenhouse Gas Emissions

NASA Astrophysics Data System (ADS)

Nottrott, A.; Tan, S. M.; He, Y.

2016-12-01

There is a global movement toward urbanization. Approximately 7% of the global population lives in just 28 megacities, occupying less than 0.1% of the total land area used by human activity worldwide. These cities contribute a significant fraction of the global budget of anthropogenic primary pollutants and greenhouse gasses. The 27 largest cities consume 9.9%, 9.3%, 6.7% and 3.0% of global gasoline, electricity, energy and water use, respectively. This impact motivates novel approaches to quantify and mitigate the growing contribution of megacity emissions to global climate change. Cities are characterized by complex topography, inhomogeneous turbulence, and variable pollutant source distributions. These features create a scale separation between local sources and urban scale emissions estimates known as the Grey-Zone. Modern computational fluid dynamics (CFD) techniques provide a quasi-deterministic, physically based toolset to bridge the scale separation gap between source level dynamics, local measurements, and urban scale emissions inventories. CFD has the capability to represent complex building topography and capture detailed 3D turbulence fields in the urban boundary layer. This presentation discusses the application of OpenFOAM to urban CFD simulations of natural gas leaks in cities. OpenFOAM is an open source software for advanced numerical simulation of engineering and environmental fluid flows. When combined with free or low cost computer aided drawing and GIS, OpenFOAM generates a detailed, 3D representation of urban wind fields. OpenFOAM was applied to model methane (CH4) emissions from various components of the natural gas distribution system, to investigate the impact of urban meteorology on mobile CH4 measurements. The numerical experiments demonstrate that CH4 concentration profiles are highly sensitive to the relative location of emission sources and buildings. Sources separated by distances of 5-10 meters showed significant differences in vertical dispersion of the plume due to building wake effects. The OpenFOAM flow fields were combined with an inverse, stochastic dispersion model to quantify and visualize the sensitivity of point sensors to upwind sources in various built environments.

Methods for Analysis of Urban Energy Systems: A New York City Case Study

NASA Astrophysics Data System (ADS)

Howard, Bianca

This dissertation describes methods developed for analysis of the New York City energy system. The analysis specifically aims to consider the built environment and its' impacts on greenhouse gas (GHG) emissions. Several contributions to the urban energy systems literature were made. First, estimates of annual energy intensities of the New York building stock were derived using a statistical analysis that leveraged energy consumption and tax assessor data collected by the Office of the Mayor. These estimates provided the basis for an assessment of the spatial distribution of building energy consumption. The energy consumption estimates were then leveraged to estimate the potential for combined heat and power (CHP) systems in New York City at both the building and microgrid scales. In aggregate, given the 2009 non-baseload GHG emissions factors for electricity production, these systems could reduce citywide GHG emissions by 10%. The operational characteristics of CHP systems were explored further considering different prime movers, climates, and GHG emissions factors. A combination of mixed integer linear programing and controlled random search algorithms were the methods used to determine the optimal capacity and operating strategies for the CHP systems under the various scenarios. Lastly a multi-regional unit commitment model of electricity and GHG emissions production for New York State was developed using data collected from several publicly available sources. The model was used to estimate average and marginal GHG emissions factors for New York State and New York City. The analysis found that marginal GHG emissions factors could reduce by 30% to 370 g CO2e/kWh in the next 10 years.

Municipal forest benefits and costs in five U.S. cities

Treesearch

E.G. McPherson; J.R. Simpson; P.J. Peper; S.E. Maco; Q. Xiao

2005-01-01

Increasingly, city trees are viewed as a best management practice to control stormwater, an urban-heat–island mitigation measure for cleaner air, a CO2-reduction option to offset emissions, and an alternative to costly new electric power plants. Measuring benefits that accrue from the community forest is the first step to altering forest...

Distribution and Source Apportionment of Polycyclic Aromatic Hydrocarbons (PAHs) in Forest Soils from Urban to Rural Areas in the Pearl River Delta of Southern China

PubMed Central

Xiao, Yihua; Tong, Fuchun; Kuang, Yuanwen; Chen, Bufeng

2014-01-01

The upper layer of forest soils (0–20 cm depth) were collected from urban, suburban, and rural areas in the Pearl River Delta of Southern China to estimate the distribution and the possible sources of polycyclic aromatic hydrocarbons (PAHs). Total concentrations of PAHs in the forest soils decreased significantly along the urban–suburban–rural gradient, indicating the influence of anthropogenic emissions on the PAH distribution in forest soils. High and low molecular weight PAHs dominated in the urban and rural forest soils, respectively, implying the difference in emission sources between the areas. The values of PAH isomeric diagnostic ratios indicated that forest soil PAHs were mainly originated from traffic emissions, mixed sources and coal/wood combustion in the urban, suburban and rural areas, respectively. Principal component analysis revealed that traffic emissions, coal burning and residential biomass combustion were the three primary contributors to forest soil PAHs in the Pearl River Delta. Long range transportation of PAHs via atmosphere from urban area might also impact the PAHs distribution in the forest soils of rural area. PMID:24599040

Assessing climate impacts of planning policies-An estimation for the urban region of Leipzig (Germany)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schwarz, Nina, E-mail: nina.schwarz@ufz.de; Bauer, Annette, E-mail: annette.bauer@ufz.de; Haase, Dagmar, E-mail: dagmar.haase@ufz.d

2011-03-15

Local climate regulation by urban green areas is an important urban ecosystem service, as it reduces the extent of the urban heat island and therefore enhances quality of life. Local and regional planning policies can control land use changes in an urban region, which in turn alter local climate regulation. Thus, this paper describes a method for estimating the impacts of current land uses as well as local and regional planning policies on local climate regulation, using evapotranspiration and land surface emissivity as indicators. This method can be used by practitioners to evaluate their policies. An application of this methodmore » is demonstrated for the case study Leipzig (Germany). Results for six selected planning policies in Leipzig indicate their distinct impacts on climate regulation and especially the role of their spatial extent. The proposed method was found to easily produce a qualitative assessment of impacts of planning policies on climate regulation.« less

Public participation GIS for improving wood burning emissions from residential heating and urban environmental management.

PubMed

López-Aparicio, Susana; Vogt, Matthias; Schneider, Philipp; Kahila-Tani, Maarit; Broberg, Anna

2017-04-15

A crowdsourcing study supported by a public participation GIS tool was designed and carried out in two Norwegian regions. The aim was to improve the knowledge about emissions from wood burning for residential heating in urban areas based on the collection of citizens' localized insights. We focus on three main issues: 1) type of dwelling and residential heating source; 2) wood consumption and type of wood appliances; and 3) citizens' perception of the urban environment. Our study shows the importance of wood burning for residential heating, and of the resulted particle emissions, in Norwegian urban areas. Citizens' localized insights on environmental perception highlight the areas in the city that require particular attention as part of clean air strategies. Information about environmental perception is combined with existing environmental data showing certain correlation. The results support the urban environmental management based on co-benefit approaches, achieving several outcomes from a single policy measure. Measures to reduce urban air pollution will have a positive impact on the citizens' environmental perception, and therefore on their quality of life, in addition to reducing the negative consequences of air pollution on human health. The characterization of residential heating by fuelwood is still a challenging activity. Our study shows the potential of a crowdsourcing method as means for bottom-up approaches designed to increase our knowledge on human activities at urban scale that result on emissions. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Annual and seasonal variability of metals and metalloids in urban and industrial soils in Alcalá de Henares (Spain).

PubMed

Peña-Fernández, A; Lobo-Bedmar, M C; González-Muñoz, M J

2015-01-01

Contamination of urban and industrial soils with trace metals has been recognized as a major concern at local, regional and global levels due to their implication on human health. In this study, concentrations of aluminum (Al), arsenic (As), beryllium (Be), cadmium (Cd), chromium (Cr), manganese (Mn), nickel (Ni), lead (Pb), tin (Sn), thallium (Tl), vanadium (V) and zinc (Zn) were determined in soil samples collected in Alcalá de Henares (Madrid, Spain) in order to evaluate the annual and seasonal variation in their levels. The results show that the soils of the industrial area have higher metals concentrations than the urban area. Principal component analysis (PCA) revealed that the two principal sources of trace metal contamination, especially Cd, Cu, Pb, and Zn in the urban soils of Alcalá can be attributed to traffic emissions, while As, Ni and Be primarily originated from industrial discharges. The seasonal variation analysis has revealed that the emission sources in the industrial area remain constant with time. However, in urban areas, both emissions and emission pathways significantly increase over time due to ongoing development. Currently, there is no hypothesis that explains the small seasonal fluctuations of trace metals in soils, since there are many factors affecting this. Owing to the fact that urban environments are becoming the human habitat, it would therefore be advisable to monitor metals and metalloids in urban soils because of the potential risks to human health. Copyright © 2014 Elsevier Inc. All rights reserved.

Elucidating secondary organic aerosol from diesel and gasoline vehicles through detailed characterization of organic carbon emissions

PubMed Central

Gentner, Drew R.; Isaacman, Gabriel; Worton, David R.; Chan, Arthur W. H.; Dallmann, Timothy R.; Davis, Laura; Liu, Shang; Day, Douglas A.; Russell, Lynn M.; Wilson, Kevin R.; Weber, Robin; Guha, Abhinav; Harley, Robert A.; Goldstein, Allen H.

2012-01-01

Emissions from gasoline and diesel vehicles are predominant anthropogenic sources of reactive gas-phase organic carbon and key precursors to secondary organic aerosol (SOA) in urban areas. Their relative importance for aerosol formation is a controversial issue with implications for air quality control policy and public health. We characterize the chemical composition, mass distribution, and organic aerosol formation potential of emissions from gasoline and diesel vehicles, and find diesel exhaust is seven times more efficient at forming aerosol than gasoline exhaust. However, both sources are important for air quality; depending on a region’s fuel use, diesel is responsible for 65% to 90% of vehicular-derived SOA, with substantial contributions from aromatic and aliphatic hydrocarbons. Including these insights on source characterization and SOA formation will improve regional pollution control policies, fuel regulations, and methodologies for future measurement, laboratory, and modeling studies. PMID:23091031

Elucidating secondary organic aerosol from diesel and gasoline vehicles through detailed characterization of organic carbon emissions.

PubMed

Gentner, Drew R; Isaacman, Gabriel; Worton, David R; Chan, Arthur W H; Dallmann, Timothy R; Davis, Laura; Liu, Shang; Day, Douglas A; Russell, Lynn M; Wilson, Kevin R; Weber, Robin; Guha, Abhinav; Harley, Robert A; Goldstein, Allen H

2012-11-06

Emissions from gasoline and diesel vehicles are predominant anthropogenic sources of reactive gas-phase organic carbon and key precursors to secondary organic aerosol (SOA) in urban areas. Their relative importance for aerosol formation is a controversial issue with implications for air quality control policy and public health. We characterize the chemical composition, mass distribution, and organic aerosol formation potential of emissions from gasoline and diesel vehicles, and find diesel exhaust is seven times more efficient at forming aerosol than gasoline exhaust. However, both sources are important for air quality; depending on a region's fuel use, diesel is responsible for 65% to 90% of vehicular-derived SOA, with substantial contributions from aromatic and aliphatic hydrocarbons. Including these insights on source characterization and SOA formation will improve regional pollution control policies, fuel regulations, and methodologies for future measurement, laboratory, and modeling studies.

Air quality benefits of universal particle filter and NOx controls on diesel trucks

NASA Astrophysics Data System (ADS)

Tao, L.; Mcdonald, B. C.; Harley, R.

2015-12-01

Heavy-duty diesel trucks are a major source of black carbon/particulate matter and nitrogen oxide emissions on urban and regional scales. These emissions are relevant to both air quality and climate change. Since 2010 in the US, new engines are required to be equipped with emission control systems that greatly reduce both PM and NOx emissions, by ~98% relative to 1988 levels. To reduce emissions from the legacy fleet of older trucks that still remain on the road, regulations have been adopted in Califonia to accelerate the replacement of older trucks and thereby reduce associated emissions of PM and NOx. Use of diesel particle filters will be widespread by 2016, and universal use of catalytic converters for NOx control is required by 2023. We assess the air quality consequences of this clean-up effort in Southern California, using the Community Multiscale Air Quality model (CMAQ), and comparing three scenarios: historical (2005), present day (2016), and future year (2023). Emissions from the motor vehicle sector are mapped at high spatial resolution based on traffic count and fuel sales data. NOx emissions from diesel engines in 2023 are expected to decrease by ~80% compared to 2005, while the fraction of NOx emitted as NO2 is expected to increase from 5 to 18%. Air quality model simulations will be analyzed to quantify changes in NO2, black carbon, particulate matter, and ozone, both basin-wide and near hot spots such as ports and major highways.

High-resolution atmospheric emission inventory of the argentine energy sector. Comparison with edgar global emission database.

PubMed

Puliafito, S Enrique; Allende, David G; Castesana, Paula S; Ruggeri, Maria F

2017-12-01

This study presents a 2014 high-resolution spatially disaggregated emission inventory (0.025° × 0.025° horizontal resolution), of the main activities in the energy sector in Argentina. The sub-sectors considered are public generation of electricity, oil refineries, cement production, transport (maritime, air, rail and road), residential and commercial. The following pollutants were included: greenhouse gases (CO 2 , CH 4 , N 2 O), ozone precursors (CO, NOx, VOC) and other specific air quality indicators such as SO 2 , PM10, and PM2.5. This work could contribute to a better geographical allocation of the pollutant sources through census based population maps. Considering the sources of greenhouse gas emissions, the total amount is 144 Tg CO2eq, from which the transportation sector emits 57.8 Tg (40%); followed by electricity generation, with 40.9 Tg (28%); residential + commercial, with 31.24 Tg (22%); and cement and refinery production, with 14.3 Tg (10%). This inventory shows that 49% of the total emissions occur in rural areas: 31% in rural areas of medium population density, 13% in intermediate urban areas and 7% in densely populated urban areas. However, if emissions are analyzed by extension (per square km), the largest impact is observed in medium and densely populated urban areas, reaching more than 20.3 Gg per square km of greenhouse gases, 297 Mg/km 2 of ozone precursors gases and 11.5 Mg/km 2 of other air quality emissions. A comparison with the EDGAR global emission database shows that, although the total country emissions are similar for several sub sectors and pollutants, its spatial distribution is not applicable to Argentina. The road and residential transport emissions represented by EDGAR result in an overestimation of emissions in rural areas and an underestimation in urban areas, especially in more densely populated areas. EDGAR underestimates 60 Gg of methane emissions from road transport sector and fugitive emissions from refining activities.

Evaluation of traffic exhaust contributions to ambient carbonaceous submicron particulate matter in an urban roadside environment in Hong Kong

NASA Astrophysics Data System (ADS)

Lee, Berto Paul; Kwok Keung Louie, Peter; Luk, Connie; Keung Chan, Chak

2017-12-01

Road traffic has significant impacts on air quality particularly in densely urbanized and populated areas where vehicle emissions are a major local source of ambient particulate matter. Engine type (i.e., fuel use) significantly impacts the chemical characteristics of tailpipe emission, and thus the distribution of engine types in traffic impacts measured ambient concentrations. This study provides an estimation of the contribution of vehicles powered by different fuels (gasoline, diesel, LPG) to carbonaceous submicron aerosol mass (PM1) based on ambient aerosol mass spectrometer (AMS) and elemental carbon (EC) measurements and vehicle count data in an urban inner city environment in Hong Kong with the aim to gauge the importance of different engine types to particulate matter burdens in a typical urban street canyon. On an average per-vehicle basis, gasoline vehicles emitted 75 and 93 % more organics than diesel and LPG vehicles, respectively, while EC emissions from diesel vehicles were 45 % higher than those from gasoline vehicles. LPG vehicles showed no appreciable contributions to EC and thus overall represented a small contributor to traffic-related primary ambient PM1 despite their high abundance (˜ 30 %) in the traffic mix. Total carbonaceous particle mass contributions to ambient PM1 from diesel engines were only marginally higher (˜ 4 %) than those from gasoline engines, which is likely an effect of recently introduced control strategies targeted at commercial vehicles and buses. Overall, gasoline vehicles contributed 1.2 µg m-3 of EC and 1.1 µ m-3 of organics, LPG vehicles 0.6 µg m-3 of organics and diesel vehicles 2.0 µg m-3 of EC and 0.7 µg m-3 of organics to ambient carbonaceous PM1.

Impacts of Urban Water Conservation Strategies on Energy, Greenhouse Gas Emissions, and Health: Southern California as a Case Study.

PubMed

Sokolow, Sharona; Godwin, Hilary; Cole, Brian L

2016-05-01

To determine how urban water conservation strategies in California cities can affect water and energy conservation efforts, reduce greenhouse gas emissions, and benefit public health. We expanded upon our 2014 health impact assessment of California's urban water conservation strategies by comparing the status quo to 2 options with the greatest potential impact on the interrelated issues of water and energy in California: (1) banning landscape irrigation and (2) expanding alternative water sources (e.g., desalination, recycled water). Among the water conservation strategies evaluated, expanded use of recycled water stood out as the water conservation strategy with potential to reduce water use, energy use, and greenhouse gas emissions, with relatively small negative impacts for the public's health. Although the suitability of recycled water for urban uses depends on local climate, geography, current infrastructure, and finances, analyses similar to that presented here can help guide water policy decisions in cities across the globe facing challenges of supplying clean, sustainable water to urban populations.

Global demographic trends and future carbon emissions.

PubMed

O'Neill, Brian C; Dalton, Michael; Fuchs, Regina; Jiang, Leiwen; Pachauri, Shonali; Zigova, Katarina

2010-10-12

Substantial changes in population size, age structure, and urbanization are expected in many parts of the world this century. Although such changes can affect energy use and greenhouse gas emissions, emissions scenario analyses have either left them out or treated them in a fragmentary or overly simplified manner. We carry out a comprehensive assessment of the implications of demographic change for global emissions of carbon dioxide. Using an energy-economic growth model that accounts for a range of demographic dynamics, we show that slowing population growth could provide 16-29% of the emissions reductions suggested to be necessary by 2050 to avoid dangerous climate change. We also find that aging and urbanization can substantially influence emissions in particular world regions.

Impacts of biogenic and anthropogenic emissions on summertime ozone formation in the Guanzhong Basin, China

NASA Astrophysics Data System (ADS)

Li, Nan; He, Qingyang; Greenberg, Jim; Guenther, Alex; Li, Jingyi; Cao, Junji; Wang, Jun; Liao, Hong; Wang, Qiyuan; Zhang, Qiang

2018-05-01

This study is the first attempt to understand the synergistic impact of anthropogenic and biogenic emissions on summertime ozone (O3) formation in the Guanzhong (GZ) Basin where Xi'an, the oldest and the most populous city (with a population of 9 million) in northwestern China, is located. Month-long (August 2011) WRF-Chem simulations with different sensitivity experiments were conducted and compared with near-surface measurements. Biogenic volatile organic compounds (VOCs) concentrations was characterized from six surface sites among the Qinling Mountains, and urban air composition was measured in Xi'an city at a tower 100 m a. s. The WRF-Chem control experiment reasonably reproduced the magnitudes and variations of observed O3, VOCs, NOx, PM2.5, and meteorological parameters, with normalized mean biases for each parameter within ±21 %. Subsequent analysis employed the factor separation approach (FSA) to quantitatively disentangle the pure and synergistic impacts of anthropogenic and/or biogenic sources on summertime O3 formation. The impact of anthropogenic sources alone was found to be dominant for O3 formation. Although anthropogenic particles reduced NO2 photolysis by up to 60 %, the anthropogenic sources contributed 19.1 ppb O3 formation on average for urban Xi'an. The abundant biogenic VOCs from the nearby forests promoted O3 formation in urban areas by interacting with the anthropogenic NOx. The calculated synergistic contribution (from both biogenic and anthropogenic sources) was up to 14.4 ppb in urban Xi'an, peaking in the afternoon. Our study reveals that the synergistic impact of individual source contributions to O3 formation should be considered in the formation of air pollution control strategies, especially for big cities in the vicinity of forests.

Evaluating efficiency-equality tradeoffs for mobile source control strategies in an urban area

PubMed Central

Levy, Jonathan I.; Greco, Susan L.; Melly, Steven J.; Mukhi, Neha

2013-01-01

In environmental risk management, there are often interests in maximizing public health benefits (efficiency) and addressing inequality in the distribution of health outcomes. However, both dimensions are not generally considered within a single analytical framework. In this study, we estimate both total population health benefits and changes in quantitative indicators of health inequality for a number of alternative spatial distributions of diesel particulate filter retrofits across half of an urban bus fleet in Boston, Massachusetts. We focus on the impact of emissions controls on primary fine particulate matter (PM2.5) emissions, modeling the effect on PM2.5 concentrations and premature mortality. Given spatial heterogeneity in baseline mortality rates, we apply the Atkinson index and other inequality indicators to quantify changes in the distribution of mortality risk. Across the different spatial distributions of control strategies, the public health benefits varied by more than a factor of two, related to factors such as mileage driven per day, population density near roadways, and baseline mortality rates in exposed populations. Changes in health inequality indicators varied across control strategies, with the subset of optimal strategies considering both efficiency and equality generally robust across different parametric assumptions and inequality indicators. Our analysis demonstrates the viability of formal analytical approaches to jointly address both efficiency and equality in risk assessment, providing a tool for decision-makers who wish to consider both issues. PMID:18793281

Vehicle Real Driving Emissions of Nitrogen Oxides in an Urban Area from a large Vehicle Fleet

NASA Astrophysics Data System (ADS)

Pöhler, Denis; Horbanski, Martin; Oesterle, Tobias; Adler, Tim; Reh, Miriam; Tirpitz, Lukas; Kanatschnig, Florian; Lampel, Joahnnes; Platt, Ulrich

2016-04-01

Nitrogen Oxide (NOx=NO +NO2) emissions by road vehicles are the major contributor for poor air quality in urban areas. High NOx concentrations, and especially NO2, are typically the most problematic pollution in cities. However, emissions vary significantly depending on the type of vehicle, its engine, the age, condition of the vehicle, driving properties, modifications and many more. Even if official NOx emission data of the manufacturer exist, they are only valid for new vehicles and the current vehicle emission scandal shows clearly that these data are often wrong. Thus, real driving emissions (RDE) of the current vehicle fleet is required. With such data the contribution of individual vehicles to the NO2 and NOx levels in urban areas can be estimated. Significant reduction of NOx concentrations can be achieved by identifying the strong emitting vehicles and excluding, replace or modify them. We developed a precise and fast ICAD (Iterative CAvity DOAS) NO2 instrument which can measure the concentration within the emission plume of vehicles under real driving conditions. The sampling was performed with an inlet at the front of a car which was following the investigated vehicles. The instrument measure NO2 and additionally CO2 with a time resolution of 2 seconds. With the observed NO2 values already strong emitters can easily be identified. With the use of known CO2 emissions, more reliable emissions for NO2 can be calculated for each vehicle. Currently the system is expanded with a NOx channel to derive the total nitrogen oxide emissions. The system was successfully applied in several studies over the last two years to investigate NO2 RDE. More than thousand vehicles were investigated. We observed that several vehicles from various brands show much higher emissions than allowed (more than a factor of 5). Highest emissions correlate for trucks and busses typically to older vehicles, what is not the case for cars. A large variability between different cars was found which could often make up a factor of 10 or more. Often new Diesel cars are one of the strongest emitters, which agree well with other findings. However, older busses and trucks feature regularly the highest emissions, but also here strong variability between different vehicle types with different exhaust treatment and modification is observed. This is especially a problem with busses from the public transport which significantly contribute to urban air pollution. Identifying first the strongest emitting busses, which should be replaced first, can help to faster improve urban air quality. New busses and trucks, beside from few exceptions, show surprisingly relatively low emissions. The exceptions indicate potentially broken NOx exhaust treatment. All these findings show that regular RDE are necessary for the whole vehicle fleet to identify strongest NOx emitters and develop strategies to reduce their emissions. They also allow to provide more accurate model calculations on total emissions in urban areas.

Sensitivity analysis of surface ozone to emission controls in Beijing and its neighboring area during the 2008 Olympic Games.

PubMed

Gao, Yi; Zhang, Meigen

2012-01-01

The regional air quality modeling system RAMS (regional atmospheric modeling system)-CMAQ (community multi-scale air quality modeling system) is applied to analyze temporal and spatial variations in surface ozone concentration over Beijing and its surrounding region from July to October 2008. Comparison of simulated and observed meteorological elements and concentration of nitrogen oxides (NOx) and ozone at one urban site and three rural sites during Olympic Games show that model can generally reproduce the main observed feature of wind, temperature and ozone, but NOx concentration is overestimated. Although ozone concentration decreased during Olympics, high ozone episodes occurred on 24 July and 24 August with concentration of 360 and 245 microg/m3 at Aoyuncun site, respectively. The analysis of sensitive test, with and without emission controls, shows that emission controls could reduce ozone concentration in the afternoon when ozone concentration was highest but increase it at night and in the morning. The evolution of the weather system during the ozone episodes (24 July and 24 August) indicates that hot and dry air and a stable weak pressure field intensified the production of ozone and allowed it to accumulate. Process analysis at the urban site and rural site shows that under favorable weather condition on 24 August, horizontal transport was the main contributor of the rural place and the pollution from the higher layer would be transported to the surface layer. On 24 July, as the wind velocity was smaller, the impact of transport on the rural place was not obvious.

Advances on interdisciplinary approaches to urban carbon

NASA Astrophysics Data System (ADS)

Romero-Lankao, P.

2015-12-01

North American urban areas are emerging as climate policy and technology innovators, urbanization process laboratories, fonts of carbon relevant experiments, hubs for grass-roots mobilization, and centers for civil-society experiments to curb carbon emissions and avoid widespread and irreversible climate impacts. Since SOCCR diverse lines of inquiry on urbanization, urban areas and the carbon cycle have advanced our understanding of some of the societal processes through which energy and land uses affect carbon. This presentation provides an overview of these diverse perspectives. It suggests the need for approaches that complement and combine the plethora of existing insights into interdisciplinary explorations of how different urbanization processes, and socio-ecological and technological components of urban areas affect the spatial and temporal patterns of carbon emissions, differentially over time and within and across cities. It also calls for a more holistic approach to examining the carbon implications of urbanization and urban areas as places, based not only on demographics or income, but also on such other interconnected features of urban development pathways as urban form, economic function, economic growth policies and climate policies.

Differences between emissions measured in urban driving and certification testing of heavy-duty diesel engines

NASA Astrophysics Data System (ADS)

Dixit, Poornima; Miller, J. Wayne; Cocker, David R.; Oshinuga, Adewale; Jiang, Yu; Durbin, Thomas D.; Johnson, Kent C.

2017-10-01

Emissions from eight heavy-duty diesel trucks (HDDTs) equipped with three different exhaust aftertreatment systems (ATS) for controlling nitrogen oxide (NOx) emissions were quantified on a chassis dynamometer using driving schedules representative of stop-and-go and free-flow driving in metropolitan areas. The three control technologies were: 1) cooled exhaust gas recirculation (CEGR) plus a diesel particulate filter (DPF); 2) CEGR and DPF plus advanced engine controls; and 3) CEGR and DPF plus selective catalytic reduction with ammonia (SCR). Results for all control technologies and driving conditions showed PM emission factors were less than the standard, while selected non-regulated emissions (ammonia, carbonyls, and C4-C12 hydrocarbons) and a greenhouse gas (nitrous oxide) were at measurement detection limits. However, NOx emission factors depended on the control technology, engine calibration, and driving mode. For example, emissions from engines with cooled-exhaust gas recirculation (CEGR) were 239% higher for stop-and-go driving as compared with free-flow. For CEGR plus selective catalytic reduction (SCR), the ratio was 450%. A deeper analysis was carried out with the assumption that emissions measured for a drive cycle on either the chassis or in-use driving would be similar. Applying the same NTE rules to the chassis data showed emissions during stop-and-go driving often exceeded the certification standard and >90% of the driving did not fall within the Not-To-Exceed (NTE) control area suggesting the NTE requirements do not provide sufficient emissions control under in-use conditions. On-road measurement of emissions using the same mobile lab while the vehicle followed a free-flow driving schedule verified the chassis results. These results have implications for scientists who build inventories using certification values instead of real world emission values and for metropolitan populations, who are exposed to elevated emissions. The differences in values between real world emissions and certification cycles should be narrowed. For example, one might use a different mix of cold and hot start testing to greater emphasize low temperature/load operation, a separate cycle to specifically characterize low-load operation, or broaden the in-use compliance testing requirements and associated conformity factors to incorporate a wider envelope of vehicle operation, especially at low load conditions. .

COMPARATIVE STUDY ON EXHAUST EMISSIONS FROM DIESEL- AND CNG-POWERED URBAN BUSES

DOE Office of Scientific and Technical Information (OSTI.GOV)

COROLLER, P; PLASSAT, G

2003-08-24

Couple years ago, ADEME engaged programs dedicated to the urban buses exhaust emissions studies. The measures associated with the reduction of atmospheric and noise pollution has particular importance in the sector of urban buses. In many cases, they illustrate the city's environmental image and contribute to reinforcing the attractiveness of public transport. France's fleet in service, presently put at about 14,000 units, consumes about 2 per cent of the total energy of city transport. It causes about 2 per cent of the HC emissions and from 4 to 6 per cent of the NOx emissions and particles. These vehicles typicallymore » have a long life span (about 15 years) and are relatively expensive to buy, about 150.000 euros per unit. Several technical solutions were evaluated to quantify, on a real condition cycle for buses, on one hand pollutants emissions, fuel consumption and on the other hand reliability, cost in real existing fleet. This paper presents main preliminary results on urban buses exhaust emission on two different cases: - existing Diesel buses, with fuel modifications (Diesel with low sulphur content), Diesel with water emulsion and bio-Diesel (30% oil ester in standard Diesel fuel); renovating CNG powered Euro II buses fleet, over representative driving cycles, set up by ADEME and partners. On these cycles, pollutants (regulated and unregulated) were measured as well as fuel consumption, at the beginning of a program and one year after to quantify reliability and increase/decrease of pollutants emissions. At the same time, some after-treatment technologies were tested under real conditions and several vehicles. Information such as fuel consumption, lubricant analysis, problem on the technology were following during a one year program. On the overall level, it is the combination of various action, pollution-reduction and renewal that will make it possible to meet the technological challenge of reducing emissions and fuel consumption by urban bus networks.« less

Non-exhaust emissions of PM and the efficiency of emission reduction by road sweeping and washing in the Netherlands.

PubMed

Keuken, Menno; Denier van der Gon, Hugo; van der Valk, Karin

2010-09-15

From research on PM(2.5) and PM(10) in 2007/2008 in the Netherlands, it was concluded that the coarse fraction (PM(2.5-10)) attributed 60% and 50% respectively, to the urban-regional and street-urban increments of PM(10). Contrary to Scandinavian and Mediterranean countries which exhibit significant seasonal variation in the coarse fraction of particulate matter (PM), in the Netherlands the coarse fraction in PM at a street location is rather constant during the year. Non-exhaust emissions by road traffic are identified as the main source for coarse PM in urban areas. Non-exhaust emissions mainly originate from re-suspension of accumulated deposited PM and road wear related particles, while primary tire and brake wear hardly contribute to the mass of non-exhaust emissions. However, tire and brake wear can clearly be identified in the total mass through the presence of the heavy metals: zinc, a tracer for tire wear and copper, a tracer for brake wear. The efficiency of road sweeping and washing to reduce non-exhaust emissions in a street-canyon in Amsterdam was investigated. The increments of the coarse fraction at a kerbside location and a housing façade location versus the urban background were measured at days with and without sweeping and washing. It was concluded that this measure did not significantly reduce non-exhaust emissions. Copyright 2010 Elsevier B.V. All rights reserved.

Emissions of black carbon and co-pollutants emitted from diesel vehicles in the Mexico City Metropolitan Area

NASA Astrophysics Data System (ADS)

Zavala, Miguel; Molina, Luisa T.; Fortner, Edward; Knighton, Berk; Herndon, Scott; Yacovitch, Tara; Floerchinger, Cody; Roscioli, Joseph; Kolb, Charles; Mejia, Jose Antonio; Sarmiento, Jorge; Paramo, Victor Hugo; Zirath, Sergio; Jazcilevich, Aron

2014-05-01

Black carbon emitted from freight, public transport, and heavy duty trucks sources is linked with adverse effects on human health. In addition, the control of emissions of black carbon, an important short-lived climate forcing agent (SLCF), has recently been considered as one of the key strategies for mitigating regional near-term climate change. Despite the availability of new emissions control technologies for reducing emissions from diesel-powered mobile sources, their introduction is still not widespread in many urban areas and there is a need to characterize real-world emission rates of black carbon from this key source. The emissions of black carbon, organic carbon, and other gaseous and particle pollutants from diesel-powered mobile sources in Mexico were characterized by deploying a mobile laboratory equipped with real-time instrumentation in Mexico City as part of the SLCFs-Mexico 2013 project. From February 25-28 of 2013 the emissions from selected diesel-powered vehicles were measured in both controlled experiments and real-world on-road driving conditions. Sampled vehicles had several emissions levels technologies, including: EPA98, EPA03, EPA04, EURO3-5, and Hybrid. All vehicles were sampled using diesel fuel and several vehicles were measured using both diesel and biodiesel fuels. Additional measurements included the use of a remote sensing unit for the co-sampling of all tested vehicles, and the installation and operation of a Portable Emissions Measurements System (PEMS) for the measurement of emissions from a test vehicle. We will present inter-comparisons of the emission factors obtained among the various vehicle technologies that were sampled during the experiment as well as the inter-comparison of results from the various sampling platforms. The results can be used to

Relative roles of emissions and meteorology in the diurnal pattern of urban PM10: analysis of the daylight saving time effect.

PubMed

Muñoz, Ricardo C

2012-06-01

Daylight saving time (DST) is a common practice in many countries, in which Official Time (OT) is abruptly shifted 1 hour with respect to solar time on two occasions every year (in fall and spring). All anthropogenic emitting processes tied to OT like job and school commuting traffic, abruptly change in this moment their timing with respect to solar time, inducing a sudden shift between emissions and the meteorological factors that control the dispersion and transport of air pollutants. Analyzing 13 years of hourly particulate matter (PM10) concentrations measured in Santiago, Chile, we demonstrate that the DST practice has observable non-trivial effects in the PM10 diurnal cycle. The clearest impact is in the morning peak of PM10 during the fall DST change, which occurs later and has on average a significant smaller magnitude in the days after the DST change as compared to the days before it. This decrease in magnitude is most remarkable because it occurs in a period of the year when overall PM10 concentrations increase due to generally worsening of the dispersion conditions. Results are shown for seven monitoring stations around the city, and for the fall and spring DST changes. They show clearly the interplay of emissions and meteorology in conditioning urban air pollution problems, highlighting the role of the morning and evening transitions of the atmospheric boundary layer in shaping the diurnal pattern of urban air pollutant concentrations.

Detection and Estimation of 2-D Distributions of Greenhouse Gas Source Concentrations and Emissions over Complex Urban Environments and Industrial Sites

NASA Astrophysics Data System (ADS)

Zaccheo, T. S.; Pernini, T.; Dobler, J. T.; Blume, N.; Braun, M.

2017-12-01

This work highlights the use of the greenhouse-gas laser imaging tomography experiment (GreenLITETM) data in conjunction with a sparse tomography approach to identify and quantify both urban and industrial sources of CO2 and CH4. The GreenLITETM system provides a user-defined set of time-sequenced intersecting chords or integrated column measurements at a fixed height through a quasi-horizontal plane of interest. This plane, with unobstructed views along the lines of sight, may range from complex industrial facilities to a small city scale or urban sector. The continuous time phased absorption measurements are converted to column concentrations and combined with a plume based model to estimate the 2-D distribution of gas concentration over extended areas ranging from 0.04-25 km2. Finally, these 2-D maps of concentration are combined with ancillary meteorological and atmospheric data to identify potential emission sources and provide first order estimates of their associated fluxes. In this presentation, we will provide a brief overview of the systems and results from both controlled release experiments and a long-term system deployment in Paris, FR. These results provide a quantitative assessment of the system's ability to detect and estimate CO2 and CH4 sources, and demonstrate its ability to perform long-term autonomous monitoring and quantification of either persistent or sporadic emissions that may have both health and safety as well as environmental impacts.

Low-cost, high-density sensor network for urban emission monitoring: BEACO2N

NASA Astrophysics Data System (ADS)

Kim, J.; Shusterman, A.; Lieschke, K.; Newman, C.; Cohen, R. C.

2017-12-01

In urban environments, air quality is spatially and temporally heterogeneous as diverse emission sources create a high degree of variability even at the neighborhood scale. Conventional air quality monitoring relies on continuous measurements with limited spatial resolution or passive sampling with high-density and low temporal resolution. Either approach averages the air quality information over space or time and hinders our attempts to understand emissions, chemistry, and human exposure in the near-field of emission sources. To better capture the true spatio-temporal heterogeneity of urban conditions, we have deployed a low-cost, high-density air quality monitoring network in San Francisco Bay Area distributed at 2km horizontal spacing. The BErkeley Atmospheric CO2 Observation Network (BEACO2N) consists of approximately 50 sensor nodes, measuring CO2, CO, NO, NO2, O­3, and aerosol. Here we describe field-based calibration approaches that are consistent with the low-cost strategy of the monitoring network. Observations that allow inference of emission factors and identification of specific local emission sources will also be presented.

40 CFR 86.099-17 - Emission control diagnostic system for 1999 and later light-duty vehicles and light-duty trucks.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Model Year New Light-Duty Vehicles, Light-Duty Trucks and Heavy-Duty Engines, and for 1985 and Later Model Year New Gasoline Fueled, Natural Gas-Fueled, Liquefied Petroleum Gas-Fueled and Methanol-Fueled... regulations shall be evaluated periodically, but no less frequently than once per Urban Dynamometer Driving...

Ozone Trends Across the United States over a Period of Decreasing NOx and VOC Emissions

EPA Science Inventory

In this work, we evaluate ambient ozone trends at urban, suburban, and rural monitoring sites across the United States over a period of decreasing NOx and VOC emissions (1998–2013). We find that decreasing ozone trends generally occur in the summer, in less urbanized areas,...

Volatile chemical products emerging as largest petrochemical source of urban organic emissions.

PubMed

McDonald, Brian C; de Gouw, Joost A; Gilman, Jessica B; Jathar, Shantanu H; Akherati, Ali; Cappa, Christopher D; Jimenez, Jose L; Lee-Taylor, Julia; Hayes, Patrick L; McKeen, Stuart A; Cui, Yu Yan; Kim, Si-Wan; Gentner, Drew R; Isaacman-VanWertz, Gabriel; Goldstein, Allen H; Harley, Robert A; Frost, Gregory J; Roberts, James M; Ryerson, Thomas B; Trainer, Michael

2018-02-16

A gap in emission inventories of urban volatile organic compound (VOC) sources, which contribute to regional ozone and aerosol burdens, has increased as transportation emissions in the United States and Europe have declined rapidly. A detailed mass balance demonstrates that the use of volatile chemical products (VCPs)-including pesticides, coatings, printing inks, adhesives, cleaning agents, and personal care products-now constitutes half of fossil fuel VOC emissions in industrialized cities. The high fraction of VCP emissions is consistent with observed urban outdoor and indoor air measurements. We show that human exposure to carbonaceous aerosols of fossil origin is transitioning away from transportation-related sources and toward VCPs. Existing U.S. regulations on VCPs emphasize mitigating ozone and air toxics, but they currently exempt many chemicals that lead to secondary organic aerosols. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Numerical Simulation of Dispersion from Urban Greenhouse Gas Sources

NASA Astrophysics Data System (ADS)

Nottrott, Anders; Tan, Sze; He, Yonggang; Winkler, Renato

2017-04-01

Cities are characterized by complex topography, inhomogeneous turbulence, and variable pollutant source distributions. These features create a scale separation between local sources and urban scale emissions estimates known as the Grey-Zone. Modern computational fluid dynamics (CFD) techniques provide a quasi-deterministic, physically based toolset to bridge the scale separation gap between source level dynamics, local measurements, and urban scale emissions inventories. CFD has the capability to represent complex building topography and capture detailed 3D turbulence fields in the urban boundary layer. This presentation discusses the application of OpenFOAM to urban CFD simulations of natural gas leaks in cities. OpenFOAM is an open source software for advanced numerical simulation of engineering and environmental fluid flows. When combined with free or low cost computer aided drawing and GIS, OpenFOAM generates a detailed, 3D representation of urban wind fields. OpenFOAM was applied to model scalar emissions from various components of the natural gas distribution system, to study the impact of urban meteorology on mobile greenhouse gas measurements. The numerical experiments demonstrate that CH4 concentration profiles are highly sensitive to the relative location of emission sources and buildings. Sources separated by distances of 5-10 meters showed significant differences in vertical dispersion of plumes, due to building wake effects. The OpenFOAM flow fields were combined with an inverse, stochastic dispersion model to quantify and visualize the sensitivity of point sensors to upwind sources in various built environments. The Boussinesq approximation was applied to investigate the effects of canopy layer temperature gradients and convection on sensor footprints.

Quantifying Volatile Organic Compound Emissions from Solvents and their Impacts on Urban Air Quality

NASA Astrophysics Data System (ADS)

Mcdonald, B. C.; De Gouw, J. A.; Gilman, J.; Ahmadov, R.; Cappa, C. D.; Frost, G. J.; Goldstein, A. H.; Jathar, S.; Jimenez, J. L.; Kim, S. W.; McKeen, S. A.; Roberts, J. M.; Trainer, M.

2016-12-01

Solvents, which consist of personal care products, paints, degreasing agents, and other chemical products, are an important anthropogenic source of volatile organic compound (VOC) emissions. Yet there are many unresolved questions related to their emission rates, chemical composition, and relative importance on urban air quality problems. Using atmospheric measurements of speciated VOCs collected at a ground site located in the Los Angeles basin during the California Nexus (CalNex) Study in 2010, and utilizing data on the composition of solvent emissions from the California Air Resources Board (CARB), we are able to reconcile solvent emissions with ambient observations. Our analysis indicates that solvent emissions are underestimated by a factor of 2-3 in the CARB inventory. We then estimate the reactivity of solvent emissions with the hydroxyl (OH) radical, and also estimate the propensity of solvent emissions to form secondary organic aerosol (SOA). Solvents contain significant fractions of oxygenated compounds, including intermediate volatility compounds, which if released to the atmosphere are potentially reactive and can lead to the formation of SOA. Overall, our results suggest that in the Los Angeles basin, solvents are now the largest anthropogenic source of VOC emissions, OH reactivity, and SOA formation, and larger than the contribution from motor vehicles. This suggests that more research is needed in better constraining this potentially important source of urban VOC emissions.

Methane emissions from natural gas infrastructure and use in the urban region of Boston, Massachusetts.

PubMed

McKain, Kathryn; Down, Adrian; Raciti, Steve M; Budney, John; Hutyra, Lucy R; Floerchinger, Cody; Herndon, Scott C; Nehrkorn, Thomas; Zahniser, Mark S; Jackson, Robert B; Phillips, Nathan; Wofsy, Steven C

2015-02-17

Methane emissions from natural gas delivery and end use must be quantified to evaluate the environmental impacts of natural gas and to develop and assess the efficacy of emission reduction strategies. We report natural gas emission rates for 1 y in the urban region of Boston, using a comprehensive atmospheric measurement and modeling framework. Continuous methane observations from four stations are combined with a high-resolution transport model to quantify the regional average emission flux, 18.5 ± 3.7 (95% confidence interval) g CH4 ⋅ m(-2) ⋅ y(-1). Simultaneous observations of atmospheric ethane, compared with the ethane-to-methane ratio in the pipeline gas delivered to the region, demonstrate that natural gas accounted for ∼ 60-100% of methane emissions, depending on season. Using government statistics and geospatial data on natural gas use, we find the average fractional loss rate to the atmosphere from all downstream components of the natural gas system, including transmission, distribution, and end use, was 2.7 ± 0.6% in the Boston urban region, with little seasonal variability. This fraction is notably higher than the 1.1% implied by the most closely comparable emission inventory.

Methane emissions from natural gas infrastructure and use in the urban region of Boston, Massachusetts

PubMed Central

McKain, Kathryn; Down, Adrian; Raciti, Steve M.; Budney, John; Hutyra, Lucy R.; Floerchinger, Cody; Herndon, Scott C.; Nehrkorn, Thomas; Zahniser, Mark S.; Jackson, Robert B.; Phillips, Nathan; Wofsy, Steven C.

2015-01-01

Methane emissions from natural gas delivery and end use must be quantified to evaluate the environmental impacts of natural gas and to develop and assess the efficacy of emission reduction strategies. We report natural gas emission rates for 1 y in the urban region of Boston, using a comprehensive atmospheric measurement and modeling framework. Continuous methane observations from four stations are combined with a high-resolution transport model to quantify the regional average emission flux, 18.5 ± 3.7 (95% confidence interval) g CH4⋅m−2⋅y−1. Simultaneous observations of atmospheric ethane, compared with the ethane-to-methane ratio in the pipeline gas delivered to the region, demonstrate that natural gas accounted for ∼60–100% of methane emissions, depending on season. Using government statistics and geospatial data on natural gas use, we find the average fractional loss rate to the atmosphere from all downstream components of the natural gas system, including transmission, distribution, and end use, was 2.7 ± 0.6% in the Boston urban region, with little seasonal variability. This fraction is notably higher than the 1.1% implied by the most closely comparable emission inventory. PMID:25617375

Urban compaction or dispersion? An air quality modelling study

NASA Astrophysics Data System (ADS)

Martins, Helena

2012-07-01

Urban sprawl is altering the landscape, with current trends pointing to further changes in land use that will, in turn, lead to changes in population, energy consumption, atmospheric emissions and air quality. Urban planners have debated on the most sustainable urban structure, with arguments in favour and against urban compaction and dispersion. However, it is clear that other areas of expertise have to be involved. Urban air quality and human exposure to atmospheric pollutants as indicators of urban sustainability can contribute to the discussion, namely through the study of the relation between urban structure and air quality. This paper addresses the issue by analysing the impacts of alternative urban growth patterns on the air quality of Porto urban region in Portugal, through a 1-year simulation with the MM5-CAMx modelling system. This region has been experiencing one of the highest European rates of urban sprawl, and at the same time presents a poor air quality. As part of the modelling system setup, a sensitivity study was conducted regarding different land use datasets and spatial distribution of emissions. Two urban development scenarios were defined, SPRAWL and COMPACT, together with their new land use and emission datasets; then meteorological and air quality simulations were performed. Results reveal that SPRAWL land use changes resulted in an average temperature increase of 0.4 °C, with local increases reaching as high as 1.5 °C. SPRAWL results also show an aggravation of PM10 annual average values and an increase in the exceedances to the daily limit value. For ozone, differences between scenarios were smaller, with SPRAWL presenting larger concentration differences than COMPACT. Finally, despite the higher concentrations found in SPRAWL, population exposure to the pollutants is higher for COMPACT because more inhabitants are found in areas of highest concentration levels.

Criteria and air-toxic emissions from in-use automobiles in the National Low-Emission Vehicle program.

PubMed

Baldauf, Rich W; Gabele, Pete; Crews, William; Snow, Richard; Cook, J Rich

2005-09-01

The U.S. Environmental Protection Agency (EPA) implemented a program to identify tailpipe emissions of criteria and air-toxic contaminants from in-use, light-duty low-emission vehicles (LEVs). EPA recruited 25 LEVs in 2002 and measured emissions on a chassis dynamometer using the cold-start urban dynamometer driving schedule of the Federal Test Procedure. The emissions measured included regulated pollutants, particulate matter, speciated hydrocarbon compounds, and carbonyl compounds. The results provided a comparison of emissions from real-world LEVs with emission standards for criteria and air-toxic compounds. Emission measurements indicated that a portion of the in-use fleet tested exceeded standards for the criteria gases. Real-time regulated and speciated hydrocarbon measurements demonstrated that the majority of emissions occurred during the initial phases of the cold-start portion of the urban dynamometer driving schedule. Overall, the study provided updated emission factor data for real-world, in-use operation of LEVs for improved emissions modeling and mobile source inventory development.

Dynamism of household carbon emissions (HCEs) from rural and urban regions of northern and southern China.

PubMed

Maraseni, Tek Narayan; Qu, Jiansheng; Yue, Bian; Zeng, Jingjing; Maroulis, Jerry

2016-10-01

China contributes 23 % of global carbon emissions, of which 26 % originate from the household sector. Due to vast variations in both climatic conditions and the affordability and accessibility of fuels, household carbon emissions (HCEs) differ significantly across China. This study compares HCEs (per person) from urban and rural regions in northern China with their counterparts in southern China. Annual macroeconomic data for the study period 2005 to 2012 were obtained from Chinese government sources, whereas the direct HCEs for different types of fossil fuels were obtained using the IPCC reference approach, and indirect HCEs were calculated by input-output analysis. Results suggest that HCEs from urban areas are higher than those from rural areas. Regardless of the regions, there is a similarity in per person HCEs in urban areas, but the rural areas of northern China had significantly higher HCEs than those from southern China. The reasons for the similarity between urban areas and differences between rural areas and the percentage share of direct and indirect HCEs from different sources are discussed. Similarly, the reasons and solutions to why decarbonising policies are working in urban areas but not in rural areas are discussed.

Air quality during the 2008 Beijing Olympics: secondary pollutants and regional impact

NASA Astrophysics Data System (ADS)

Wang, T.; Nie, W.; Gao, J.; Xue, L. K.; Gao, X. M.; Wang, X. F.; Qiu, J.; Poon, C. N.; Meinardi, S.; Blake, D.; Wang, S. L.; Ding, A. J.; Chai, F. H.; Zhang, Q. Z.; Wang, W. X.

2010-08-01

This paper presents the first results of the measurements of trace gases and aerosols at three surface sites in and outside Beijing before and during the 2008 Olympics. The official air pollution index near the Olympic Stadium and the data from our nearby site revealed an obvious association between air quality and meteorology and different responses of secondary and primary pollutants to the control measures. Ambient concentrations of vehicle-related nitrogen oxides (NOx) and volatile organic compounds (VOCs) at an urban site dropped by 25% and 20-45% in the first two weeks after full control was put in place, but the levels of ozone, sulfate and nitrate in PM2.5 increased by 16%, 64%, 37%, respectively, compared to the period prior to the full control; wind data and back trajectories indicated the contribution of regional pollution from the North China Plain. Air quality (for both primary and secondary pollutants) improved significantly during the Games, which were also associated with the changes in weather conditions (prolonged rainfall, decreased temperature, and more frequent air masses from clean regions). A comparison of the ozone data at three sites on eight ozone-pollution days, when the air masses were from the southeast-south-southwest sector, showed that regional pollution sources contributed >34-88% to the peak ozone concentrations at the urban site in Beijing. Regional sources also contributed significantly to the CO concentrations in urban Beijing. Ozone production efficiencies at two sites were low (~3 ppbv/ppbv), indicating that ozone formation was being controlled by VOCs. Compared with data collected in 2005 at a downwind site, the concentrations of ozone, sulfur dioxide (SO2), total sulfur (SO2+PM2.5 sulfate), carbon monoxide (CO), reactive aromatics (toluene and xylenes) sharply decreased (by 8-64%) in 2008, but no significant changes were observed for the concentrations of PM2.5, fine sulfate, total odd reactive nitrogen (NOy), and longer lived alkanes and benzene. We suggest that these results indicate the success of the government's efforts in reducing emissions of SO2, CO, and VOCs in Beijing, but increased regional emissions during 2005-2008. More stringent control of regional emissions will be needed for significant reductions of ozone and fine particulate pollution in Beijing.

Global typology of urban energy use and potentials for an urbanization mitigation wedge

PubMed Central

Creutzig, Felix; Baiocchi, Giovanni; Bierkandt, Robert; Pichler, Peter-Paul; Seto, Karen C.

2015-01-01

The aggregate potential for urban mitigation of global climate change is insufficiently understood. Our analysis, using a dataset of 274 cities representing all city sizes and regions worldwide, demonstrates that economic activity, transport costs, geographic factors, and urban form explain 37% of urban direct energy use and 88% of urban transport energy use. If current trends in urban expansion continue, urban energy use will increase more than threefold, from 240 EJ in 2005 to 730 EJ in 2050. Our model shows that urban planning and transport policies can limit the future increase in urban energy use to 540 EJ in 2050 and contribute to mitigating climate change. However, effective policies for reducing urban greenhouse gas emissions differ with city type. The results show that, for affluent and mature cities, higher gasoline prices combined with compact urban form can result in savings in both residential and transport energy use. In contrast, for developing-country cities with emerging or nascent infrastructures, compact urban form, and transport planning can encourage higher population densities and subsequently avoid lock-in of high carbon emission patterns for travel. The results underscore a significant potential urbanization wedge for reducing energy use in rapidly urbanizing Asia, Africa, and the Middle East. PMID:25583508

Intake fraction of PM2.5 and NOX from vehicle emissions in Beijing based on personal exposure data

NASA Astrophysics Data System (ADS)

Du, Xuan; Wu, Ye; Fu, Lixin; Wang, Shuxiao; Zhang, Shaojun; Hao, Jiming

2012-09-01

The intake fraction (iF) is the portion of attributable population intake of a source emissions, and is used to link pollutant emissions and population exposure. This study is the first work that reported individual intake fraction of PM2.5 and NOX from vehicle emissions based on personal exposure data in China. We employed PM2.5 and NOX measurement data from 24-h personal exposure sampling and concentration monitoring in traffic environments in the urban area of Beijing to estimate the individual intake fraction (iFi). iFi distributions are presented in microenvironments (traffic, work, home) for adults and children. The individual results are used to calculate the intake fraction for the children group and the adults group in the urban area of Beijing. The iF of PM2.5 for the whole population of these two groups in Beijing is 153 per million, which is significantly higher than those estimates in the United States (1-50 per million) and Mexico (23-120 per million). The iF of NOX is 70 per million, among which the intake in the traffic micro-environment ranks first compared to the iF in the home and office due to a high accumulation of NOX concentration in vehicles. PM2.5 and NOX intake fraction values from vehicle emissions in this study are from at least several times to one order of magnitude higher than those from other industry sources in China. This strongly suggests the health risk from vehicle emissions is significantly higher. Therefore, to protect human health, especially for the large number of people living in the cities of China, controlling vehicle emissions should be the highest priority.

Aircraft observations of the urban CO2 dome in London and calculated daytime CO2 fluxes at the urban-regional scale

NASA Astrophysics Data System (ADS)

Font, Anna; Morgui, Josep Anton; Grimmond, Sue; Barratt, Benjamin

2013-04-01

Traffic, industry and energy production and consumption within urban boundaries emit great amounts of CO2 into the atmosphere, creating an urban increment of CO2 mixing ratios compared to the surrounding rural atmosphere. Monitoring CO2 within these 'urban domes' has been proposed as a means to evaluate the effectiveness of policies aiming to mitigate and reduce CO2 urban emissions (CMEGGE, 2010). London is the biggest urban conurbation in Western Europe with more than 8 million inhabitants, and it emitted roughly 45000 ktn CO2 in 2010 (DECC, 2012). In order to develop and implement observational strategies to measure the contribution of urban areas into the global carbon cycle, two airborne surveys were deployed using the Natural and Environment Research Council - Airborne Research and Survey Facility (NERC-ARSF). High frequency measurements of atmospheric CO2, O3, particles and meteorological variables were taken over London in October 2011 and July 2012. CO2 mixing ratios were measured by a Non-Dispersive IR instrument developed by AOS. In July 2012, a Cavity Ring-Down Spectroscopy (CDRS) instrument developed by PICARRO was deployed measuring CO2, CH4 and water vapour at 1Hz resolution. The objectives of the campaigns were to measure the CO2 dome over London and to calculate CO2 emissions at the urban-regional-scale. London was crossed by two transects (SW-NE and SSE-NNW) at an altitude of 360 m and vertical profiles up to 2000 m were carried out to characterize the structure of the atmosphere. Aircraft measurements allowed observation on how CO2 domes were shaped by meteorological conditions. In October 2011, the mean CO2 mixing ratio measured in London was on average 2 ppmv higher than the suburban measurements within the boundary layer. However, under low wind speeds, the CO2 mixing ratio in the urban mixing ratio peaked in central London (>10 ppmv) and decreased towards the city boundaries. Under windy conditions, the structure of the urban dome was dispersed downwind, with peak concentrations displaced from the urban centre along the main wind direction. The urban-regional surface CO2 flux was calculated for four days in October 2011 by either the Integrative Mass Boundary Layer (IMBL) or the Column Integration method (CIM), dependent on meteorological conditions. The diurnal CO2 flux in London obtained from the aircraft observations ranged from 36 to 71 μmol CO2 m-2 s-1 during the day time. This compared well with continuous measurements of CO2 exchange by an eddy-covariance system located in central London. The day-to-day variability observed in the calculated CO2 fluxes responded to the spatial variability of the influence area and emissions that observations were sensitive to. This study provides an example how aircraft surveys in urban areas can be used to estimate CO2 surface fluxes at the urban-regional scale. It also presents an important cross-validation of two independent measurement-based methods to infer the contribution of urban areas to climate change in terms of CO2 emissions that complement bottom-up emissions inventories. References Committee on Methods for Estimating Greenhouse Gas Emissions (2010), The National Academia Press. DECC (2012), http://www.decc.gov.uk/en/content/cms/statistics/indicators/ni186/ni186.aspx

Inter-annual variability and trend detection of urban CO2, CH4 and CO emissions

NASA Astrophysics Data System (ADS)

Lauvaux, T.; Deng, A.; Gurney, K. R.; Nathan, B.; Ye, X.; Oda, T.; Karion, A.; Hardesty, M.; Harvey, R. M.; Richardson, S.; Whetstone, J. R.; Hutyra, L.; Davis, K. J.; Brewer, A.; Gaudet, B. J.; Turnbull, J. C.; Sweeney, C.; Shepson, P. B.; Miles, N.; Bonin, T.; Wu, K.; Balashov, N. V.

2017-12-01

The Indianapolis Flux (INFLUX) Experiment has conducted an unprecedented volume of atmospheric greenhouse gas measurements across the Indianapolis metropolitan area from aircraft, remote-sensing, and tower-based observational platforms. Assimilated in a high-resolution urban inversion system, atmospheric data provide an independent constraint to existing emission products, directly supporting the integration of economic data into urban emission systems. We present here the first multi-year assessment of carbon dioxide (CO2), methane (CH4), and carbon monoxide (CO) emissions from anthropogenic activities in comparison to multiple bottom-up emission products. Biogenic CO2 fluxes are quantified using an optimized biogeochemical model at high resolution, further refined within the atmospheric inversion system. We also present the first sector-based inversion by jointly assimilating CO2 and CO mixing ratios to quantify the dominant sectors of emissions over the entire period (2012-2015). The detected trend in CO2 emissions over 2012-2015 from both bottom-up emission products and tower-based inversions agree within a few percent, with a decline in city emissions over the 3-year time period. Major changes occur at the primary power plant, suggesting a decrease in energy production within the city limits. The joint assimilation of CO2 and CO mixing ratios confirms the absence of trends in other sectors. However, top-down and bottom-up approaches tend to disagree annually, with a decline in urban emissions suggested by atmospheric data in 2014 that is several months earlier than is observed in the bottom-up products. Concerning CH4 emissions, the inversion shows a decrease since mid-2014 which may be due to lower landfill emissions or lower energy consumption (from coal and natural gas). This first demonstration of a high-accuracy long-term greenhouse gas measurement network merged with a high-resolution bottom-up information system highlights the potential for informing and supporting policy makers on the successful implementation of emission reduction targets. We show here how the combination of information sources supports the evaluation of mitigation policies and helps development of understanding regarding the mechanisms driving emission trends at the level of economical sectors.

Evaluating Urban Methane Emissions with a Light Rail Vehicle Platform in Salt Lake City, UT

NASA Astrophysics Data System (ADS)

Mitchell, L.; Fasoli, B.; Crosman, E.; Lin, J. C.; Bowling, D. R.; Ehleringer, J. R.

2016-12-01

Urban environments are characterized by both spatial complexity and temporal variability, each of which present challenges for measurement strategies aimed at constraining estimates of greenhouse gas emissions and air quality. To address these challenges we initiated a project in December 2014 to measure trace species (CO2, CH4, O3, and Particulate Matter) by way of a Utah Transit Authority (UTA) electricity-powered light rail vehicle whose route traverses the metropolitan Salt Lake Valley in Utah, USA on an hourly basis, retracing the same route through commercial, residential, suburban, and rural typologies. Light rail vehicles present advantages as a measurement platform, including the absence of in-situ fossil fuel emissions, regular repeated transects across an urban region that provide both spatial and temporal information, and relatively low operating costs. We will present initial results investigating methane point sources and evaluating the magnitude and temporal characteristics of these emissions.

Comparison of Weekly Cycle of NO2 Satellite Retrievals and NO(x) Emission Inventories for the Continental United States

NASA Technical Reports Server (NTRS)

Kaynak, B.; Hu, Y.; Martin, R. V.; Sioris, C. E.; Russell, A. G.

2009-01-01

Spatially resolved weekly NO2 variations are obtained from 2003 to 2005 Scanning Imaging Absorption Spectrometer for Atmospheric Cartography (SCIAMACHY) tropospheric NO2 columns for three different types of regions: urban, rural, and rural-point (rural with significant electricity generation unit (EGU) emissions). Regions are compared for magnitudes and weekly profiles. Rural regions do not show any weekly pattern, whereas urban areas show a distinct decrease on the weekends. Rural regions with EGUs show a slight decrease on Sundays. When compared with estimated mobile and stationary nitrogen oxides (NO(x)) emissions from the year 2004 for seven cities, the satellite data have greater variation during weekdays (Monday-Friday). Overall comparisons show that SCIAMACHY derived NO2 correlate well with estimated NO(x) emissions for urban and rural but less for rural-point regions.

The impacts of rapid land use changes on regional climate, air quality and atmospheric sensitivities to emissions

NASA Astrophysics Data System (ADS)

Yim, S. H. L.; Wong, M.; Wang, Y.; Chan, A.

2016-12-01

The Pearl River Delta region has undergone a rapid urbanization in recent several decades. Literature has found significant impacts on climate and air quality. Previous studies however mainly investigated the impacts on climate and ozone concentration in a relatively short time period. None of them investigated the monthly variation in impacts on ozone (O3) and fine particulate matters (PM2.5), and the atmospheric sensitivity to emissions, which are particularly important for atmospheric scientists and policy makers. In this study, we used the state-of-the-art atmospheric regional models with the technique of high-order decoupled direct method to quantify the impacts of urbanization on not only the regional climate and O3 concentration but also the O3 sensitivities to emissions of nitrogen oxides and volatile organic compound. Our preliminary results show that the urbanization shifts the energy budget from latent heat to sensible heat and ground heat storage. These changes cause an increase in ground level temperature and planetary boundary layer with a maximum annual change of 1.7ºC and 330m, respectively, and a reduction of relative humidity and wind speed up to 9.6% and 0.5m/s, respectively. Such changes are favorable to air pollution. Compared to the two land-use scenarios, we found that O3 increases by 14.2%, while PM2.5 decreases by 16.9% in urban areas. Due to urbanization, the O3 sensitivities to nitrogen oxides (NOx) and volatile organic compound (VOC) change by 2.4% and 47.5%, respectively. This indicates that the atmospheric response in the region tends to be more sensitive to emission changes after urbanization. Our findings pinpoint that urbanization can significantly affect not only the regional climate and air quality but also the atmospheric responses to emission changes, highlighting the significant interactions between land-use policies, and climate and air quality policies.

Could US mayors achieve the entire US Paris climate target?

NASA Astrophysics Data System (ADS)

Gurney, K. R.; Huang, J.; Hutchins, M.; Liang, J.

2017-12-01

After the recent US Federal Administration announcement not to adhere to the Paris Accords, 359 mayors (and counting) in the US pledged to maintain their commitments, reducing emissions within their jurisdictions by 26-28% from their 2005 levels by the year 2025. While important, this leaves a large portion of the US landscape, and a large amount of US emissions, outside of the Paris commitment. With Federal US policy looking unlikely to change, could additional effort by US cities overcome the gap in national policy and achieve the equivalent US national Paris commitment? How many cities would be required and how deep would reductions need to be? Up until now, this question could not be reliably resolved due to lack of data at the urban scale. Here, we answer this question with new data - the Vulcan V3.0 FFCO2 emissions data product - through examination of the total US energy related CO2 emissions from cities. We find that the top 500 urban areas in the US could meet the national US commitment to the Paris Accords with a reduction of roughly 30% below their 2015 levels by the year 2025. This is driven by the share of US emissions emanating from cities, particularly the largest cohort. Indeed, as the number of urban areas taking on CO2 reduction targets grows, the less the reduction burden on any individual city. In this presentation, we provide an analysis of US urban CO2 emissions and US climate policy, accounting for varying definitions of urban areas, emitting sectors and the tradeoff between the number of policy-active cities and the CO2 reduction burden.

CH4 emissions from European Major Population Centers: Results from aircraft-borne CH4 in-situ observations during EMeRGe-Europe campaign 2017

NASA Astrophysics Data System (ADS)

Roiger, A.; Klausner, T.; Schlager, H.; Ziereis, H.; Huntrieser, H.; Baumann, R.; Eirenschmalz, L.; Joeckel, P.; Mertens, M.; Fisher, R.; Bauguitte, S.; Young, S.; Andrés Hernández, M. D.

2017-12-01

Urban environments represent large and diffuse area sources of CH4 including emissions from pipeline leaks, industrial/sewage treatment plants, and landfills. However, there is little knowledge about the exact magnitude of these emissions and their contribution to total anthropogenic CH4. Especially in the context of an urbanizing world, a better understanding of the methane footprint of urban areas is crucial, both with respect to mitigation and projection of climate impacts. Aircraft-borne in-situ measurements are particularly useful to both quantify emissions from such area sources, as well as to study their impact on the regional distribution. However, airborne CH4 observations downstream of European cities are especially sparse.Here we report from aircraft-borne CH4 in-situ measurements as conducted during the HALO aircraft campaign EMeRGe (Effect of Megacities on the Transport and Transformation of Pollutants on the Regional to Global Scales) in July 2017, which was led by the University of Bremen, Germany. During seven research flights, emissions from a variety of European (Mega)-cities were probed at different altitudes from 3km down to 500m, including measurements in the outflows of London, Rome, Po Valley, Ruhr and Benelux. We will present and compare the CH4 distribution measured downstream of the various studied urban hot-spots. With the help of other trace gas measurements (including e.g. CO2, CO, O3, SO2), observed methane enhancements will be attributed to the different potential source types. Finally, by the combination of in-situ measurements and regional model simulations using the EMAC-MECO(n) model, the contribution of emissions from urban centers to the regional methane budget over Europe will be discussed.

Development of a high temporal-spatial resolution vehicle emission inventory based on NRT traffic data and its impact on air pollution in Beijing - Part 1: Development and evaluation of vehicle emission inventory

NASA Astrophysics Data System (ADS)

Jing, B. Y.; Wu, L.; Mao, H. J.; Gong, S. L.; He, J. J.; Zou, C.; Song, G. H.; Li, X. Y.; Wu, Z.

2015-10-01

As the ownership of vehicles and frequency of utilization increase, vehicle emissions have become an important source of air pollution in Chinese cities. An accurate emission inventory for on-road vehicles is necessary for numerical air quality simulation and the assessment of implementation strategies. This paper presents a bottom-up methodology based on the local emission factors, complemented with the widely used emission factors of Computer Programme to Calculate Emissions from Road Transport (COPERT) model and near real time (NRT) traffic data on road segments to develop a high temporal-spatial resolution vehicle emission inventory (HTSVE) for the urban Beijing area. To simulate real-world vehicle emissions accurately, the road has been divided into segments according to the driving cycle (traffic speed) on this road segment. The results show that the vehicle emissions of NOx, CO, HC and PM were 10.54 × 104, 42.51 × 104 and 2.13 × 104 and 0.41 × 104 Mg, respectively. The vehicle emissions and fuel consumption estimated by the model were compared with the China Vehicle Emission Control Annual Report and fuel sales thereafter. The grid-based emissions were also compared with the vehicular emission inventory developed by the macro-scale approach. This method indicates that the bottom-up approach better estimates the levels and spatial distribution of vehicle emissions than the macro-scale method, which relies on more information. Additionally, the on-road vehicle emission inventory model and control effect assessment system in Beijing, a vehicle emission inventory model, was established based on this study in a companion paper (He et al., 2015).

Capital requirements and fuel-cycle energy and emissions impacts of potential PNGV fuels.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Johnson, L.; Mintz, M.; Singh, M.

1999-03-11

Our study reveals that supplying gasoline-equivalent demand for the low-market-share scenario requires a capital investment of less thanmore » $$40 billion for all fuels except H{sub 2}, which will require a total cumulative investment of $$150 billion. By contrast, cumulative capital investments under the high-market-share scenario are $50 billion for LNG, $90 billion for ethanol, $100 billion for methanol, $160 billion for CNG and DME, and $560 billion for H{sub 2}. Although these substantial capital requirements are spread over many years, their magnitude could pose a challenge to the widespread introduction of 3X vehicles. Fossil fuel use by US light-duty vehicles declines significantly with introduction of 3X vehicles because of fuel-efficiency improvements for 3X vehicles and because of fuel substitution (which applies to the nonpetroleum-fueled alternatives). Petroleum use for light-duty vehicles in 2030 is reduced by as much as 45% relative to the reference scenario. GHG emissions follow a similar pattern. Total GHG emissions decline by 25-30% with most of the propulsion system/fuel alternatives. For those using renewable fuels (i.e., ethanol and H{sub 2} from solar energy), GHG emissions drop by 33% (H{sub 2}) and 45% (ethanol). Among urban air pollutants, urban NOX emissions decline slightly for 3X vehicles using CIDI and SIDI engines and drop substantially for fuel-cell vehicles. Urban CO emissions decline for CIDI and FCV alternatives, while VOC emissions drop significantly for all alternatives except RFG-, methanol-, and ethanol-fueled SIDI engines. With the exception of CIDI engines fueled by RFD, FT50, or B20 (which increase urban PM{sub 10} emissions by over 30%), all propulsion system/fuel alternatives reduce urban PM{sub 10} emissions. Reductions are approximately 15-20% for fuel cells and for methanol-, ethanol-, CNG-, or LPG-fueled SIDI engines. Table 3 qualitatively summarizes impacts of the 13 alternatives on capital requirements and on energy use and emissions relative to the reference scenario. The table clearly shows the trade-off between costs and benefits. For example, while H{sub 2} FCVs have the greatest incremental capital needs, they offer the largest energy and emissions benefits. On the basis of the cost and benefit changes shown, methanol and gasoline FCVs appear to have particularly promising benefits-to-costs ratios.« less

Ubiquity of bisphenol A in the atmosphere.

PubMed

Fu, Pingqing; Kawamura, Kimitaka

2010-10-01

Bisphenol A (BPA) is a suspected endocrine disruptor in the environment. However, little is known about its distribution and transport in the atmosphere. Here, the concentrations of BPA in the atmospheric aerosols from urban, rural, marine, and the polar regions were measured using solvent extraction/derivatization and gas chromatography/mass spectrometry technique. The concentrations of BPA (1-17,400 pg m(-3)) ranged over 4 orders of magnitude in the world with a declining trend from the continent (except for the Antarctica) to remote sites. A positive correlation was found between BPA and 1,3,5-triphenylbenzene, a tracer for plastic burning, in urban regions, indicating that the open burning of plastics in domestic waste should be a significant emission source of atmospheric BPA. Our results suggest that the ubiquity of BPA in the atmosphere may raise a requirement for the evaluation of health effects of BPA in order to control its emission sources, for example, from plastic burning. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Aged particles derived from emissions of coal-fired power plants: The TERESA field results

PubMed Central

Kang, Choong-Min; Gupta, Tarun; Ruiz, Pablo A.; Wolfson, Jack M.; Ferguson, Stephen T.; Lawrence, Joy E.; Rohr, Annette C.; Godleski, John; Koutrakis, Petros

2013-01-01

The Toxicological Evaluation of Realistic Emissions Source Aerosols (TERESA) study was carried out at three US coal-fired power plants to investigate the potential toxicological effects of primary and photochemically aged (secondary) particles using in situ stack emissions. The exposure system designed successfully simulated chemical reactions that power plant emissions undergo in a plume during transport from the stack to receptor areas (e.g., urban areas). Test atmospheres developed for toxicological experiments included scenarios to simulate a sequence of atmospheric reactions that can occur in a plume: (1) primary emissions only; (2) H2SO4 aerosol from oxidation of SO2; (3) H2SO4 aerosol neutralized by gas-phase NH3; (4) neutralized H2SO4 with secondary organic aerosol (SOA) formed by the reaction of α-pinene with O3; and (5) three control scenarios excluding primary particles. The aged particle mass concentrations varied significantly from 43.8 to 257.1 μg/m3 with respect to scenario and power plant. The highest was found when oxidized aerosols were neutralized by gas-phase NH3 with added SOA. The mass concentration depended primarily on the ratio of SO2 to NOx (particularly NO) emissions, which was determined mainly by coal composition and emissions controls. Particulate sulfate (H2SO4 + neutralized sulfate) and organic carbon (OC) were major components of the aged particles with added SOA, whereas trace elements were present at very low concentrations. Physical and chemical properties of aged particles appear to be influenced by coal type, emissions controls and the particular atmospheric scenarios employed. PMID:20462390

Modeling urban building energy use: A review of modeling approaches and procedures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Wenliang; Zhou, Yuyu; Cetin, Kristen

With rapid urbanization and economic development, the world has been experiencing an unprecedented increase in energy consumption and greenhouse gas (GHG) emissions. While reducing energy consumption and GHG emissions is a common interest shared by major developed and developing countries, actions to enable these global reductions are generally implemented at the city scale. This is because baseline information from individual cities plays an important role in identifying economical options for improving building energy efficiency and reducing GHG emissions. Numerous approaches have been proposed for modeling urban building energy use in the past decades. This paper aims to provide an up-to-datemore » review of the broad categories of energy models for urban buildings and describes the basic workflow of physics-based, bottom-up models and their applications in simulating urban-scale building energy use. Because there are significant differences across models with varied potential for application, strengths and weaknesses of the reviewed models are also presented. This is followed by a discussion of challenging issues associated with model preparation and calibration.« less

Modeling urban building energy use: A review of modeling approaches and procedures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Wenliang; Zhou, Yuyu; Cetin, Kristen

With rapid urbanization and economic development, the world has been experiencing an unprecedented increase in energy consumption and greenhouse gas (GHG) emissions. While reducing energy consumption and GHG emissions is a common interest shared by major developed and developing countries, actions to enable these global reductions are generally implemented at the city scale. This is because baseline information from individual cities plays an important role in identifying economical options for improving building energy efficiency and reducing GHG emissions. Numerous approaches have been proposed for modeling urban building energy use in the past decades. Our paper aims to provide an up-to-datemore » review of the broad categories of energy models for urban buildings and describes the basic workflow of physics-based, bottom-up models and their applications in simulating urban-scale building energy use. Because there are significant differences across models with varied potential for application, strengths and weaknesses of the reviewed models are also presented. We then follow this with a discussion of challenging issues associated with model preparation and calibration.« less

Impacts of Urban Water Conservation Strategies on Energy, Greenhouse Gas Emissions, and Health: Southern California as a Case Study

PubMed Central

Sokolow, Sharona; Godwin, Hilary

2016-01-01

Objectives. To determine how urban water conservation strategies in California cities can affect water and energy conservation efforts, reduce greenhouse gas emissions, and benefit public health. Methods. We expanded upon our 2014 health impact assessment of California's urban water conservation strategies by comparing the status quo to 2 options with the greatest potential impact on the interrelated issues of water and energy in California: (1) banning landscape irrigation and (2) expanding alternative water sources (e.g., desalination, recycled water). Results. Among the water conservation strategies evaluated, expanded use of recycled water stood out as the water conservation strategy with potential to reduce water use, energy use, and greenhouse gas emissions, with relatively small negative impacts for the public’s health. Conclusions. Although the suitability of recycled water for urban uses depends on local climate, geography, current infrastructure, and finances, analyses similar to that presented here can help guide water policy decisions in cities across the globe facing challenges of supplying clean, sustainable water to urban populations. PMID:26985606

Modeling urban building energy use: A review of modeling approaches and procedures

DOE PAGES

Li, Wenliang; Zhou, Yuyu; Cetin, Kristen; ...

2017-11-13

With rapid urbanization and economic development, the world has been experiencing an unprecedented increase in energy consumption and greenhouse gas (GHG) emissions. While reducing energy consumption and GHG emissions is a common interest shared by major developed and developing countries, actions to enable these global reductions are generally implemented at the city scale. This is because baseline information from individual cities plays an important role in identifying economical options for improving building energy efficiency and reducing GHG emissions. Numerous approaches have been proposed for modeling urban building energy use in the past decades. Our paper aims to provide an up-to-datemore » review of the broad categories of energy models for urban buildings and describes the basic workflow of physics-based, bottom-up models and their applications in simulating urban-scale building energy use. Because there are significant differences across models with varied potential for application, strengths and weaknesses of the reviewed models are also presented. We then follow this with a discussion of challenging issues associated with model preparation and calibration.« less

Do US metropolitan core counties have lower scope 1 and 2 CO2 emissions than less urbanized counties?

NASA Astrophysics Data System (ADS)

Tamayao, M. M.; Blackhurst, M. F.; Matthews, H. S.

2014-10-01

Recent sustainability research has focused on urban systems given their high share of environmental impacts and potential for centralized impact mitigation. Recent research emphasizes descriptive statistics from place-based case studies to argue for policy action. This limits the potential for general insights and decision support. Here, we implement generalized linear and multiple linear regression analyses to obtain more robust insights on the relationship between urbanization and greenhouse gas (GHG) emissions in the US We used consistently derived county-level scope 1 and scope 2 GHG inventories for our response variable while predictor variables included dummy-coded variables for county geographic type (central, outlying, and nonmetropolitan), median household income, population density, and climate indices (heating degree days (HDD) and cooling degree days (CDD)). We find that there is not enough statistical evidence indicating per capita scope 1 and 2 emissions differ by geographic type, ceteris paribus. These results are robust for different assumed electricity emissions factors. We do find statistically significant differences in per capita emissions by sector for different county types, with transportation and residential emissions highest in nonmetropolitan (rural) counties, transportation emissions lowest in central counties, and commercial sector emissions highest in central counties. These results indicate the importance of regional land use and transportation dynamics when planning local emissions mitigation measures.

Criteria pollutant and greenhouse gas emissions from CNG transit buses equipped with three-way catalysts compared to lean-burn engines and oxidation catalyst technologies.

PubMed

Yoon, Seungju; Collins, John; Thiruvengadam, Arvind; Gautam, Mridul; Herner, Jorn; Ayala, Alberto

2013-08-01

Engine and exhaust control technologies applied to compressed natural gas (CNG) transit buses have advanced from lean-burn, to lean-burn with oxidation catalyst (OxC), to stoichiometric combustion with three-way catalyst (TWC). With this technology advancement, regulated gaseous and particulate matter emissions have been significantly reduced. Two CNG transit buses equipped with stoichiometric combustion engines and TWCs were tested on a chassis dynamometer, and their emissions were measured. Emissions from the stoichiometric engines with TWCs were then compared to the emissions from lean-burn CNG transit buses tested in previous studies. Stoichiometric combustion with TWC was effective in reducing emissions of oxides of nitrogen (NO(x)), particulate matter (PM), and nonmethane hydrocarbon (NMHC) by 87% to 98% depending on pollutants and test cycles, compared to lean combustion. The high removal efficiencies exceeded the emission reduction required from the certification standards, especially for NO(x) and PM. While the certification standards require 95% and 90% reductions for NO(x) and PM, respectively, from the engine model years 1998-2003 to the engine model year 2007, the measured NO(x) and PM emissions show 96% and 95% reductions, respectively, from the lean-burn engines to the stoichiometric engines with TWC over the transient Urban Dynamometer Driving Schedule (UDDS) cycle. One drawback of stoichiometric combustion with TWC is that this technology produces higher carbon monoxide (CO) emissions than lean combustion. In regard to controlling CO emissions, lean combustion with OxC is more effective than stoichiometric combustion. Stoichiometric combustion with TWC produced higher greenhouse gas (GHG) emissions including carbon dioxide (CO2) and methane (CH4) than lean combustion during the UDDS cycle, but lower GHG emissions during the steady-state cruise cycle. Stoichiometric combustion with three-way catalyst is currently the best emission control technology available for compressed natural gas (CNG) transit buses to meet the stringent U.S. Environmental Protection Agency (EPA) 2010 heavy-duty engine NO(x) emissions standard. For existing lean-burn CNG transit buses in the fleet, oxidation catalyst would be the most effective retrofit technology for the control of NMHC and CO emissions.

Top-down NOX emissions over European cities from LOTOS-EUROS simulated and OMI observed tropospheric NO2 columns using the Exponentially Modified Gaussian approach

NASA Astrophysics Data System (ADS)

Verstraeten, Willem W.; Folkert Boersma, K.; Douros, John; Williams, Jason E.; Eskes, Henk H.; Delcloo, Andy

2017-04-01

High nitrogen oxides concentrations at the surface (NOX = NO + NO2) impact humans and ecosystem badly and play a key role in tropospheric chemistry. Surface NOX emissions drive major processes in regional and global chemistry transport models (CTM). NOX contributes to the formation of acid rain, act as aerosol precursors and is an important trace gas for the formation of tropospheric ozone (O3). Via tropospheric O3, NOX indirectly affects the production of the hydroxyl radical which controls the chemical lifetime of key atmospheric pollutants and reactive greenhouse gases. High NOX emissions are mainly observed in polluted regions produced by anthropogenic combustion from industrial, traffic and household activities typically observed in large and densely populated urban areas. Accurate NOX inventories are essential, but state-of the- art emission databases may vary substantially and uncertainties are high since reported emissions factors may differ in order of magnitude and more. To date, the modelled NO2 concentrations and lifetimes have large associated uncertainties due to the highly non-linear small-scale chemistry that occurs in urban areas and uncertainties in the reaction rate data, missing nitrogen (N) species and volatile organic compounds (VOC) emissions, and incomplete knowledge of nitrogen oxides chemistry. Any overestimation in the chemical lifetime may mask missing NOX chemistry in current CTM's. By simultaneously estimating both the NO2 lifetime and concentrations, for instance by using the Exponentially Modified Gaussian (EMG), a better surface NOX emission flux estimate can be obtained. Here we evaluate if the EMG methodology can reproduce the emissions input from the tropospheric NO2 columns simulated by the LOTOS-EUROS (Long Term Ozone Simulation-European Ozone Simulation) CTM model. We apply the EMG methodology on LOTOS-EUROS simulated tropospheric NO2 columns for the period April-September 2013 for 21 selected European urban areas under windy conditions (surface wind speeds > 3 m s-1). We then compare the top-down derived surface NOX emissions with the 2011 MACC-III emission inventory, used in the LOTOS-EUROS model as input to simulate the NO2 columns. We also apply the EMG methodology on OMI (Ozone Monitoring Instrument) tropospheric NO2 column data, providing us with real-time observation-based estimates of midday NO2 lifetime and NOX emissions over 21 European cities in 2013. Results indicate that the top-down derived NOX emissions from LOTOS-EUROS (respectively OMI) are comparable with the MACC-III inventory with a R2 of 0.99 (respectively R2 = 0.79). For St-Petersburg and Moscow the top-down NOX estimates from 2013 OMI data are biased low compared to the MACC-III inventory which uses a 2011 NOX emissions update.

Numerical modelling of vehicular pollution dispersion: The application of computational fluid dynamics techniques, a case study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vanderheyden, M.D.; Dajka, S.C.; Sinclair, R.

1997-12-31

Numerical modelling of vehicular emissions using the United States Environmental Protection Agency`s CALINE4 and CAL3QHC dispersion models to predict air quality impacts in the vicinity of roadways is a widely accepted means of evaluating vehicular emissions impacts. The numerical models account for atmospheric dispersion in both open or suburban terrains. When assessing roadways in urban areas with numerous large buildings, however, the models are unable to account for the complex airflows and therefore do not provide satisfactory estimates of pollutant concentrations. Either Wind Tunnel Modelling or Computational Fluid Dynamics (CFD) techniques can be used to assess the impact of vehiclemore » emissions in an urban core. This paper presents a case study where CFD is used to predict worst-case air quality impacts for two development configurations: an existing roadway configuration and a proposed configuration with an elevated pedestrian walkway. In assessing these configurations, worst-case meteorology and traffic conditions are modeled to allow for the prediction of pollutant concentrations due to vehicular emissions on two major streets in Hong Kong. The CFD modelling domain is divided up into thousands of control volumes. Each of these control volumes has a central point called a node where velocities, pollutant concentration and other auxiliary variables are calculated. The region of interest, the pedestrian link and its immediate surroundings, has a denser distribution of nodes in order to give a better resolution of local flow details. Separate CFD modelling runs were undertaken for each development configuration for wind direction increments of 15 degrees. For comparison of the development scenarios, pollutant concentrations (carbon monoxide, nitrogen dioxide and particulate matter) are predicted at up to 99 receptor nodes representing sensitive locations.« less

Evaluation of MEGAN predicted biogenic isoprene emissions at urban locations in Southeast Texas

NASA Astrophysics Data System (ADS)

Kota, Sri Harsha; Schade, Gunnar; Estes, Mark; Boyer, Doug; Ying, Qi

2015-06-01

Summertime isoprene emissions in the Houston area predicted by the Model of Emissions of Gases and Aerosol from Nature (MEGAN) version 2.1 during the 2006 TexAQS study were evaluated using a source-oriented Community Multiscale Air Quality (CMAQ) Model. Predicted daytime isoprene concentrations at nine surface sites operated by the Texas Commission of Environmental Quality (TCEQ) were significantly higher than local observations when biogenic emissions dominate the total isoprene concentrations, with mean normalized bias (MNB) ranges from 2.0 to 7.7 and mean normalized error (MNE) ranges from 2.2 to 7.7. Predicted upper air isoprene and its first generation oxidation products of methacrolein (MACR) and methyl vinyl ketone (MVK) were also significantly higher (MNB = 8.6, MNE = 9.1) than observations made onboard of NOAA's WP-3 airplane, which flew over the urban area. Over-prediction of isoprene and its oxidation products both at the surface and the upper air strongly suggests that biogenic isoprene emissions in the Houston area are significantly overestimated. Reducing the emission rates by approximately 3/4 was necessary to reduce the error between predictions and observations. Comparison of gridded leaf area index (LAI), plant functional type (PFT) and gridded isoprene emission factor (EF) used in MEGAN modeling with estimates of the same factors from a field survey north of downtown Houston showed that the isoprene over-prediction is likely caused by the combined effects of a large overestimation of the gridded EF in urban Houston and an underestimation of urban LAI. Nevertheless, predicted ozone concentrations in this region were not significantly affected by the isoprene over-predictions, while predicted isoprene SOA and total SOA concentrations can be higher by as much as 50% and 13% using the higher isoprene emission rates, respectively.

Source identification of PM2.5 at a port and an adjacent urban site in a coastal city of China: Impact of ship emissions and port activities.

PubMed

Xu, Lingling; Jiao, Ling; Hong, Zhenyu; Zhang, Yanru; Du, Wenjiao; Wu, Xin; Chen, Yanting; Deng, Junjun; Hong, Youwei; Chen, Jinsheng

2018-09-01

Daily PM 2.5 samples were collected simultaneously at an urban site (UB) and a nearby port-industrial site (PI) on the coast of southeastern China from April 2015 to January 2016. The PM 2.5 mass concentration at the PI (51.9μgm -3 ) was significantly higher than that at the UB. The V concentration at the PI was also significantly higher and well-correlated to the urban value, which suggests that shipping emissions had a significant impact on the PI and, to a lesser extent, on the urban area. A positive matrix factorization (PMF) analysis showed that secondary aerosols were the dominant contribution of PM 2.5 at both sites (36.4% at the PI and 27.2% at the UB), while the contribution of industry and ship emissions identified by V, Mn, and Ba at the PI (26.1%) were double those at the UB. The difference in each source contribution among the trajectory clusters that included significant differences and insignificant differences from the UB to the PI provided insight into the role of local impacts. With regards to the UB, local potential sources play important roles in industry and ship emissions, traffic emissions, fugitive dust, and in their contributions to secondary aerosols. A conditional probability function further revealed that the ship emissions and port activities distributed in the NE, E, and SSE wind sectors were responsible for the source contributions of industry and ship emissions and secondary aerosols at the UB. This study provides an example of investigating the impact of ship emissions and port activities on the surrounding air environment using land-based measurements. Copyright © 2018 Elsevier B.V. All rights reserved.

Modal emissions modeling with real traffic data

DOT National Transportation Integrated Search

1999-01-01

This report details the use of a modal emissions model to estimate the relative emissions of CO due to changes in vehicle operating characteristics on urban roadways. The Davis Institute for Transportation Studies Emissions Model (DITSEM) was selecte...

Urban ecosystems and the North American carbon cycle

Treesearch

D.E. Pataki; R.J. Alig; A.S. Fung; E. Golubiewski; C.A. Kennedy; E.G. McPherson; D.J. Nowak; R.V. Pouyat; P. Romero Lankao

2006-01-01

Approximately 75-80% of the population of North America currently lives in urban areas as defined by national census bureaus, and urbanization is continuing to increase. Future trajectories of fossil fuel emissions are associated with a high degree of uncertainty; however, if the activities of urban residents and the rate of urban land conversion can be captured in...

Using Sediment Records to Reconstruct Historical Inputs Combustion-Derived Contaminants to Urban Airsheds/Watersheds: A Case Study From the Puget Sound

NASA Astrophysics Data System (ADS)

Louchouarn, P. P.; Kuo, L.; Brandenberger, J.; Marcantonio, F.; Wade, T. L.; Crecelius, E.; Gobeil, C.

2008-12-01

Urban centers are major sources of combustion-derived particulate matter (e.g. black carbon (BC), polycyclic aromatic hydrocarbons (PAH), anhydrosugars) and volatile organic compounds to the atmosphere. Evidence is mounting that atmospheric emissions from combustion sources remain major contributors to air pollution of urban systems. For example, recent historical reconstructions of depositional fluxes for pyrogenic PAHs close to urban systems have shown an unanticipated reversal in the trends of decreasing emissions initiated during the mid-20th Century. Here we compare a series of historical reconstructions of combustion emission in urban and rural airsheds over the last century using sedimentary records. A complex suite of combustion proxies (BC, PAHs, anhydrosugars, stable lead concentrations and isotope signatures) assisted in elucidating major changes in the type of atmospheric aerosols originating from specific processes (i.e. biomass burning vs. fossil fuel combustion) or fuel sources (wood vs. coal vs. oil). In all studied locations, coal continues to be a major source of combustion-derived aerosols since the early 20th Century. Recently, however, oil and biomass combustion have become substantial additional sources of atmospheric contamination. In the Puget Sound basin, along the Pacific Northwest region of the U.S., rural locations not impacted by direct point sources of contamination have helped assess the influence of catalytic converters on concentrations of oil-derived PAH and lead inputs since the early 1970s. Although atmospheric deposition of lead has continued to drop since the introduction of catalytic converters and ban on leaded gasoline, PAH inputs have "rebounded" in the last decade. A similar steady and recent rise in PAH accumulations in urban systems has been ascribed to continued urban sprawl and increasing vehicular traffic. In the U.S., automotive emissions, whether from gasoline or diesel combustion, are becoming a major source of combustion-derived PM and BC to the atmosphere and have started to replace coal as the major source in some surficial reservoirs. This increased urban influence of gasoline and diesel combustion on BC emissions was also observed in Europe both from model estimates as well as from measured fluxes in recent lake sediments.

Atmospheric ammonia and its impacts on regional air quality over the megacity of Shanghai, China.

PubMed

Wang, Shanshan; Nan, Jialiang; Shi, Chanzhen; Fu, Qingyan; Gao, Song; Wang, Dongfang; Cui, Huxiong; Saiz-Lopez, Alfonso; Zhou, Bin

2015-10-30

Atmospheric ammonia (NH3) has great environmental implications due to its important role in ecosystem and global nitrogen cycle, as well as contribution to secondary particle formation. Here, we report long-term continuous measurements of NH3 at different locations (i.e. urban, industrial and rural) in Shanghai, China, which provide an unprecedented portrait of temporal and spatial characteristics of atmospheric NH3 in and around this megacity. In addition to point emission sources, air masses originated from or that have passed over ammonia rich areas, e.g. rural and industrial sites, increase the observed NH3 concentrations inside the urban area of Shanghai. Remarkable high-frequency NH3 variations were measured at the industrial site, indicating instantaneous nearby industrial emission peaks. Additionally, we observed strong positive exponential correlations between NH4(+)/(NH4(+)+NH3) and sulfate-nitrate-ammonium (SNA) aerosols, PM2.5 mass concentrations, implying a considerable contribution of gas-to-particle conversion of ammonia to SNA aerosol formation. Lower temperature and higher humidity conditions were found to favor the conversion of gaseous ammonia to particle ammonium, particularly in autumn. Although NH3 is currently not included in China's emission control policies of air pollution precursors, our results highlight the urgency and importance of monitoring gaseous ammonia and improving its emission inventory in and around Shanghai.

Atmospheric ammonia and its impacts on regional air quality over the megacity of Shanghai, China

PubMed Central

Wang, Shanshan; Nan, Jialiang; Shi, Chanzhen; Fu, Qingyan; Gao, Song; Wang, Dongfang; Cui, Huxiong; Saiz-Lopez, Alfonso; Zhou, Bin

2015-01-01

Atmospheric ammonia (NH3) has great environmental implications due to its important role in ecosystem and global nitrogen cycle, as well as contribution to secondary particle formation. Here, we report long-term continuous measurements of NH3 at different locations (i.e. urban, industrial and rural) in Shanghai, China, which provide an unprecedented portrait of temporal and spatial characteristics of atmospheric NH3 in and around this megacity. In addition to point emission sources, air masses originated from or that have passed over ammonia rich areas, e.g. rural and industrial sites, increase the observed NH3 concentrations inside the urban area of Shanghai. Remarkable high-frequency NH3 variations were measured at the industrial site, indicating instantaneous nearby industrial emission peaks. Additionally, we observed strong positive exponential correlations between NH4+/(NH4++NH3) and sulfate-nitrate-ammonium (SNA) aerosols, PM2.5 mass concentrations, implying a considerable contribution of gas-to-particle conversion of ammonia to SNA aerosol formation. Lower temperature and higher humidity conditions were found to favor the conversion of gaseous ammonia to particle ammonium, particularly in autumn. Although NH3 is currently not included in China’s emission control policies of air pollution precursors, our results highlight the urgency and importance of monitoring gaseous ammonia and improving its emission inventory in and around Shanghai. PMID:26514559

Global time trends in PAH emissions from motor vehicles

PubMed Central

Shen, Huizhong; Tao, Shu; Wang, Rong; Wang, Bin; Shen, Guofeng; Li, Wei; Su, Shenshen; Huang, Ye; Wang, Xilong; Liu, Wenxin; Li, Bengang; Sun, Kang

2013-01-01

Emission from motor vehicles is the most important source of polycyclic aromatic hydrocarbons (PAHs) in urban areas. Emission factors of individual PAHs for motor vehicles reported in the literature varied 4 to 5 orders of magnitude, leading to high uncertainty in emission inventory. In this study, key factors affecting emission factors of PAHs (EFPAH) for motor vehicles were evaluated quantitatively based on thousands of EFPAH measured in 16 countries for over 50 years. The result was used to develop a global emission inventory of PAHs from motor vehicles. It was found that country and vehicle model year are the most important factors affecting EFPAH, which can be quantified using a monovariate regression model with per capita gross domestic production (purchasing power parity) as a sole independent variable. On average, 29% of variation in log-transformed EFPAH could be explained by the model, which was equivalent to 90% reduction in overall uncertainty on arithmetic scale. The model was used to predict EFPAH and subsequently PAH emissions from motor vehicles for various countries in the world during a period from 1971 to 2030. It was estimated that the global emission reached its peak value of approximate 101 Gg in 1978 and decreased afterwards due to emission control in developed countries. The annual emission picked up again since 1990 owing to accelerated energy consumption in China and other developing countries. With more and more rigid control measures taken in the developing world, global emission of PAHs is currently passing its second peak. It was predicted that the emission would decrease from 77 Gg in 2010 to 42 Gg in 2030. PMID:24198716

Variability in operation-based NO(x) emission factors with different test routes, and its effects on the real-driving emissions of light diesel vehicles.

PubMed

Lee, Taewoo; Park, Junhong; Kwon, Sangil; Lee, Jongtae; Kim, Jeongsoo

2013-09-01

The objective of this study is to quantify the differences in NO(x) emissions between standard and non-standard driving and vehicle operating conditions, and to estimate by how much NO(x) emissions exceed the legislative emission limits under typical Korean road traffic conditions. Twelve Euro 3-5 light-duty diesel vehicles (LDDVs) manufactured in Korea were driven on a chassis dynamometer over the standard New European Driving Cycle (NEDC) and a representative Korean on-road driving cycle (KDC). NO(x) emissions, average speeds and accelerations were calculated for each 1-km trip segment, so called averaging windows. The results suggest that the NO(x) emissions of the tested vehicles are more susceptible to variations in the driving cycles than to those in the operating conditions. Even under comparable operating conditions, the NO(x) control capabilities of vehicles differ from each other, i.e., NO(x) control is weaker for the KDC than for the NEDC. The NO(x) emissions over the KDC for given vehicle operating conditions exceed those over the NEDC by more than a factor of 8. Consequently, on-road NO(x) emission factors are estimated here to exceed the Euro 5 emission limit by up to a factor of 8, 4 and 3 for typical Korean urban, rural, and motorway road traffic conditions, respectively. Our findings support the development of technical regulations for supplementary real-world emission tests for emission certification and the corresponding research actions taken by automotive industries. Copyright © 2013 Elsevier B.V. All rights reserved.

NMVOCs speciated emissions from mobile sources and their effect on air quality and human health in the metropolitan area of Buenos Aires, Argentina

NASA Astrophysics Data System (ADS)

D'Angiola, Ariela; Dawidowski, Laura; Gomez, Dario; Granier, Claire

2014-05-01

Since 2007, more than half of the world's population live in urban areas. Urban atmospheres are dominated by pollutants associated with vehicular emissions. Transport emissions are an important source of non-methane volatile organic compounds (NMVOCs) emissions, species of high interest because of their negative health effects and their contribution to the formation of secondary pollutants responsible for photochemical smog. NMVOCs emissions are generally not very well represented in emission inventories and their speciation presents a high level of uncertainty. In general, emissions from South American countries are still quite unknown for the international community, and usually present a high degree of uncertainty due to the lack of available data to compile emission inventories. Within the Inter-American Institute for Global Change Research (IAI, www.iai.int) projects, UMESAM (Urban Mobile Emissions in South American Megacities) and SAEMC (South American Emissions, Megacities and Climate, http://saemc.cmm.uchile.cl/), the effort was made to compute on-road transport emission inventories for South American megacities, namely Bogota, Buenos Aires, Lima, Sao Paulo and Santiago de Chile, considering megacities as urban agglomerations with more than 5 million inhabitants. The present work is a continuation of these projects, with the aim to extend the calculated NMVOCs emissions inventory into the individual species required by CTMs. The on-road mobile sector of the metropolitan area of Buenos Aires (MABA), Argentina, accounted for 70 Gg of NMVOCs emissions for 2006, without considering two-wheelers. Gasoline light-duty vehicles were responsible for 64% of NMVOCs emissions, followed by compressed natural gas (CNG) light-duty vehicles (22%), diesel heavy-duty vehicles (11%) and diesel light-duty vehicles (7%). NMVOCs emissions were speciated according to fuel and technology, employing the European COPERT (Ntziachristos & Samaras, 2000) VOCs speciation scheme for gasoline and diesel vehicles and the USEPA SPECIATE (Simon et al., 2010) profile for CNG vehicles. NMVOCs emissions were composed of 31% aromatic compounds, 29% linear alkanes, 20% olefins, 12% ramified alkanes, 7% aldehydes and negligible contributions from cycloalkanes, ketones, Polycyclic Aromatic Hydrocarbons (PAHs) and other NMVOCs. Aromatic compounds dominated gasoline light-duty vehicles' emissions (~45%), while linear alkanes those of CNG light-duty vehicles (~80%). Aldehydes' contributions increased for diesel light and heavy-duty vehicles. VOCs speciation schemes for transport emissions were collected from the literature from Europe, USA, Asia, Oceania and Latin America with the aim to account for the associated uncertainty by compound for each fuel and technology type. The resulting individual NMVOCs emissions were used to calculate the corresponding tropospheric ozone formation (Carter, 1994), as well as the human toxicity potential in terms of 1.4 dichlorobenzene. Olefins and aromatic compounds in terms of species, and gasoline in terms of fuels, were found to impose the highest risk in urban environments regarding air quality and human health.

Aircraft-based Observations and Modeling of Wintertime Submicron Aerosol Composition over the Northeastern U.S.

NASA Astrophysics Data System (ADS)

Shah, V.; Jaegle, L.; Schroder, J. C.; Campuzano-Jost, P.; Jimenez, J. L.; Guo, H.; Sullivan, A.; Weber, R. J.; Green, J. R.; Fiddler, M.; Bililign, S.; Lopez-Hilfiker, F.; Lee, B. H.; Thornton, J. A.

2017-12-01

Submicron aerosol particles (PM1) remain a major air pollution concern in the urban areas of northeastern U.S. While SO2 and NOx emission controls have been effective at reducing summertime PM1 concentrations, this has not been the case for wintertime sulfate and nitrate concentrations, suggesting a nonlinear response during winter. During winter, organic aerosol (OA) is also an important contributor to PM1 mass despite low biogenic emissions, suggesting the presence of important urban sources. We use aircraft-based observations collected during the Wintertime INvestigation of Transport, Emissions and Reactivity (WINTER) campaign (Feb-March 2015), together with the GEOS-Chem chemical transport model, to investigate the sources and chemical processes governing wintertime PM1 over the northeastern U.S. The mean observed concentration of PM1 between the surface and 1 km was 4 μg m-3, about 30% of which was composed of sulfate, 20% nitrate, 10% ammonium, and 40% OA. The model reproduces the observed sulfate, nitrate and ammonium concentrations after updates to HNO3 production and loss, SO2 oxidation, and NH3 emissions. We find that 65% of the sulfate formation occurs in the aqueous phase, and 55% of nitrate formation through N2O5 hydrolysis, highlighting the importance of multiphase and heterogeneous processes during winter. Aqueous-phase sulfate production and the gas-particle partitioning of nitrate and ammonium are affected by atmospheric acidity, which in turn depends on the concentration of these species. We examine these couplings with GEOS-Chem, and assess the response of wintertime PM1 concentrations to further emission reductions based on the U.S. EPA projections for the year 2023. For OA, we find that the standard GEOS-Chem simulation underestimates the observed concentrations, but a simple parameterization developed from previous summer field campaigns is able to reproduce the observations and the contribution of primary and secondary OA. We find that residential wood combustion accounts for about 25% of the OA, while secondary production from urban anthropogenic VOCs accounts for the rest. We examine how OA concentrations may change as a result of changing emissions for the year 2023.

Influence factors and forecast of carbon emission in China: structure adjustment for emission peak

NASA Astrophysics Data System (ADS)

Wang, B.; Cui, C. Q.; Li, Z. P.

2018-02-01

This paper introduced Principal Component Analysis and Multivariate Linear Regression Model to verify long-term balance relationships between Carbon Emissions and the impact factors. The integrated model of improved PCA and multivariate regression analysis model is attainable to figure out the pattern of carbon emission sources. Main empirical results indicate that among all selected variables, the role of energy consumption scale was largest. GDP and Population follow and also have significant impacts on carbon emission. Industrialization rate and fossil fuel proportion, which is the indicator of reflecting the economic structure and energy structure, have a higher importance than the factor of urbanization rate and the dweller consumption level of urban areas. In this way, some suggestions are put forward for government to achieve the peak of carbon emissions.

Gaseous emissions from compressed natural gas buses in urban road and highway tests in China.

PubMed

Yue, Tingting; Chai, Fahe; Hu, Jingnan; Jia, Ming; Bao, Xiaofeng; Li, Zhenhua; He, Liqang; Zu, Lei

2016-10-01

The natural gas vehicle market is rapidly developing throughout the world, and the majority of such vehicles operate on compressed natural gas (CNG). However, most studies on the emission characteristics of CNG vehicles rely on laboratory chassis dynamometer measurements, which do not accurately represent actual road driving conditions. To further investigate the emission characteristics of CNG vehicles, two CNG city buses and two CNG coaches were tested on public urban roads and highway sections. Our results show that when speeds of 0-10km/hr were increased to 10-20km/hr, the CO 2 , CO, nitrogen oxide (NO x ), and total hydrocarbon (THC) emission factors decreased by (71.6±4.3)%, (65.6±9.5)%, (64.9±9.2)% and (67.8±0.3)%, respectively. In this study, The Beijing city buses with stricter emission standards (Euro IV) did not have lower emission factors than the Chongqing coaches with Euro II emission standards. Both the higher emission factors at 0-10km/hr speeds and the higher percentage of driving in the low-speed regime during the entire road cycle may have contributed to the higher CO 2 and CO emission factors of these city buses. Additionally, compared with the emission factors produced in the urban road tests, the CO emission factors of the CNG buses in highway tests decreased the most (by 83.2%), followed by the THC emission factors, which decreased by 67.1%. Copyright © 2016. Published by Elsevier B.V.

TESTING CMAQ CHEMISTRY SENSITIVITIES IN BASE CHASE AND EMISSION CONTROL RUNS AT SEARCH AND SOS 99 SURFACE SITES IN THE SOUTHEASTERN UNITED STATES

EPA Science Inventory

CMAQ was run to simulate urban conditions in the southeastern U.S. in July 1999 at 32, 8, and 2 km grid spacings. Runs were made with two older mechanisms, Carbon Bond IV (CB4) and the Regional Acid Deposition Model, version 2 (RADM2), and with the more recent California Statewid...

Fossil Fuel Combustion-Related Emissions Dominate Atmospheric Ammonia Sources during Severe Haze Episodes: Evidence from 15N-Stable Isotope in Size-Resolved Aerosol Ammonium

NASA Astrophysics Data System (ADS)

Pan, Y.; Tian, S.; Liu, D.; Fang, Y.; Zhu, X.; Zhang, Q.; Zheng, B.; Michalski, G. M.; Wang, Y.

2016-12-01

The reduction of ammonia (NH3) emissions is urgently needed due to its major contributions to nitrogen deposition and particle pollution. However, the relative contributions of individual NH3 sources are unclear, and debate remains over whether agricultural emissions dominate atmospheric NH3 in urban areas. Based on the chemical and isotopic measurements of size-resolved aerosols in urban Beijing, China, we find that the natural abundance of 15N (expressed using δ15N values) of ammonium (NH4+) in fine particles varies with the development of haze episodes, ranging from -37.1‰ to -21.7‰ during clean/dusty days (relative humidity: ˜ 40%), to -13.1‰ to +5.8‰ during hazy days (relative humidity: 70-90%). After factoring the isotope exchange between NH3 gas and aerosol NH4+, the δ15N value of the initial NH3 during hazy days is found to be -14.5‰ to -1.6‰, which indicates fossil fuel-based emissions. These emissions contribute 90% of the total NH3 during hazy days in urban Beijing. This work demonstrates the analysis of δ15N values of aerosol NH4+ to be a promising new tool for partitioning atmospheric NH3 sources, providing policy makers with insights into NH3 emissions and secondary aerosols for regulation in urban environments. This work also shed lights on the sources of nitrogen deposition in downwind ecosystems.

Fossil Fuel Combustion-Related Emissions Dominate Atmospheric Ammonia Sources during Severe Haze Episodes: Evidence from (15)N-Stable Isotope in Size-Resolved Aerosol Ammonium.

PubMed

Pan, Yuepeng; Tian, Shili; Liu, Dongwei; Fang, Yunting; Zhu, Xiaying; Zhang, Qiang; Zheng, Bo; Michalski, Greg; Wang, Yuesi

2016-08-02

The reduction of ammonia (NH3) emissions is urgently needed due to its role in aerosol nucleation and growth causing haze formation during its conversion into ammonium (NH4(+)). However, the relative contributions of individual NH3 sources are unclear, and debate remains over whether agricultural emissions dominate atmospheric NH3 in urban areas. Based on the chemical and isotopic measurements of size-resolved aerosols in urban Beijing, China, we find that the natural abundance of (15)N (expressed using δ(15)N values) of NH4(+) in fine particles varies with the development of haze episodes, ranging from -37.1‰ to -21.7‰ during clean/dusty days (relative humidity: ∼ 40%), to -13.1‰ to +5.8‰ during hazy days (relative humidity: 70-90%). After accounting for the isotope exchange between NH3 gas and aerosol NH4(+), the δ(15)N value of the initial NH3 during hazy days is found to be -14.5‰ to -1.6‰, which indicates fossil fuel-based emissions. These emissions contribute 90% of the total NH3 during hazy days in urban Beijing. This work demonstrates the analysis of δ(15)N values of aerosol NH4(+) to be a promising new tool for partitioning atmospheric NH3 sources, providing policy makers with insights into NH3 emissions and secondary aerosols for regulation in urban environments.

Atmospheric emissions of typical toxic heavy metals from open burning of municipal solid waste in China

NASA Astrophysics Data System (ADS)

Wang, Yan; Cheng, Ke; Wu, Weidong; Tian, Hezhong; Yi, Peng; Zhi, Guorui; Fan, Jing; Liu, Shuhan

2017-03-01

Municipal solid waste (MSW) contains considerable hazardous components and the widely-distributed open MSW burning in heavily-populated urban areas can cause direct exposure of hazardous materials to citizens. By determining the best available representation of composition-varying and time-varying emission factors with fuzzy mathematics method and S-shape curves, a comprehensive atmospheric emission inventories of 9 typical toxic heavy metals (THMs, e.g. mercury (Hg), arsenic (As), lead (Pb), cadmium (Cd), chromium (Cr), selenium (Se), copper (Cu), zinc (Zn), and nickel (Ni)) from open MSW burning activities in China is established during the period of 2000-2013 for the first time. Further, the emissions in 2013 are allocated at a high spatial resolution of 0.5° × 0.5° grid by surrogate indexes. The results show that 9 typical THMs emissions from open MSW burning are estimated at 21.25 t for Hg, 131.52 t for As, 97.12 t for Pb, 10.12 t for Cd, 50.58 t for Cr, 81.95 t for Se, 382.42 t for Cu, 1790.70 t for Zn, and 43.50 t for Ni, respectively. In terms of spatial variation, the majority of emissions are concentrated in relatively developed and densely-populated regions, especially for the eastern, central and southern regions. Moreover, future emissions are also projected for the period of 2015-2030 based on different scenarios of the independent and collaborative effects of control proposals including minimizing waste, improving MSW incineration ratio, and enhancing waste sorting and recycling, etc. The collaborative effect of the above proposals is expected to bring the most effective reduction to THMs emissions from open MSW burning in China except for Hg. The results will be supplementary to all anthropogenic emissions and useful for relevant policy-making and the improvement of urban air quality as well as human health.

Quantifying Uncontrolled Air Emissions from Two Florida Landfills

EPA Science Inventory

Landfill gas emissions, if left uncontrolled, contribute to air toxics, climate change, trospospheric ozone, and urban smog. Measuring emissions from landfills presents unique challenges due to the large and variable source area, spatial and temporal variability of emissions, and...

Emission factor of ammonia (NH3) from on-road vehicles in China: tunnel tests in urban Guangzhou

NASA Astrophysics Data System (ADS)

Liu, Tengyu; Wang, Xinming; Wang, Boguang; Ding, Xiang; Deng, Wei; Lü, Sujun; Zhang, Yanli

2014-05-01

Ammonia (NH3) is the primary alkaline gas in the atmosphere that contributes to formation of secondary particles. Emission of NH3 from vehicles, particularly gasoline powered light duty vehicles equipped with three-way catalysts, is regarded as an important source apart from emissions from animal wastes and soils, yet measured emission factors for motor vehicles are still not available in China, where traffic-related emission has become an increasingly important source of air pollutants in urban areas. Here we present our tunnel tests for NH3 from motor vehicles under ‘real world conditions’ in an urban roadway tunnel in Guangzhou, a central city in the Pearl River Delta (PRD) region in south China. By attributing all NH3 emissions in the tunnel to light-duty gasoline vehicles, we obtained a fuel-based emission rate of 2.92 ± 0.18 g L-1 and a mileage-based emission factor of 229.5 ± 14.1 mg km-1. These emission factors were much higher than those measured in the United States while measured NO x emission factors (7.17 ± 0.60 g L-1 or 0.56 ± 0.05 g km-1) were contrastingly near or lower than those previously estimated by MOBILE/PART5 or COPERT IV models. Based on the NH3 emission factors from this study, on-road vehicles accounted for 8.1% of NH3 emissions in the PRD region in 2006 instead of 2.5% as estimated in a previous study using emission factors taken from the Emission Inventory Improvement Program (EIIP) in the United States.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nyhan, Marguerite; Sobolevsky, Stanislav; Kang, Chaogui

Air pollution related to traffic emissions pose an especially significant problem in cities; this is due to its adverse impact on human health and well-being. Previous studies which have aimed to quantify emissions from the transportation sector have been limited by either simulated or coarsely resolved traffic volume data. Emissions inventories form the basis of urban pollution models, therefore in this study, Global Positioning System (GPS) trajectory data from a taxi fleet of over 15,000 vehicles were analyzed with the aim of predicting air pollution emissions for Singapore. This novel approach enabled the quantification of instantaneous drive cycle parameters inmore » high spatio-temporal resolution, which provided the basis for a microscopic emissions model. Carbon dioxide (CO2), nitrogen oxides (NOx), volatile organic compounds (VOCs) and particulate matter (PM) emissions were thus estimated. Highly localized areas of elevated emissions levels were identified, with a spatio-temporal precision not possible with previously used methods for estimating emissions. Relatively higher emissions areas were mainly concentrated in a few districts that were the Singapore Downtown Core area, to the north of the central urban region and to the east of it. Daily emissions quantified for the total motor vehicle population of Singapore were found to be comparable to another emissions dataset Results demonstrated that high resolution spatio-temporal vehicle traces detected using GPS in large taxi fleets could be used to infer highly localized areas of elevated acceleration and air pollution emissions in cities, and may become a complement to traditional emission estimates, especially in emerging cities and countries where reliable fine-grained urban air quality data is not easily available. This is the first study of its kind to investigate measured microscopic vehicle movement in tandem with microscopic emissions modeling for a substantial study domain.« less

Trace Gases and Aerosol Optical Properties Over the US Mid-Atlantic During Summer 2001

NASA Astrophysics Data System (ADS)

Doddridge, B. G.; Piety, C. A.

2001-12-01

Anthropogenic emissions from rapid urban sprawl, commuter/commercial traffic and industrialization along the East Coast of the United States have a profound effect on urban and regional air quality. During summer 2001 we used a light aircraft research platform operated from North Carolina northward through Pennsylvania measuring meteorological scalars, selected trace gases and aerosol optical properties on selected pollution episode days. The goal of this research is to gain an improved understanding of the sources, sinks, transport and photochemical transformations controlling the observed abundance of photochemical oxidants and fine particulate haze over the U.S. Mid-Atlantic region. The aircraft research capabilities will be described, over 60 research flights totaling in excess of 160 flight hours summarized, and key findings presented. Although westerly transport of remnant ozone and haze along with precursors can make substantial contributions to observed urban corridor air quality aloft, significant production downwind of the urban center often can occur within the planetary boundary layer during the afternoon hours.

Correction of Measured Taxicab Exhaust Emission Data Based on Cmem Modle

NASA Astrophysics Data System (ADS)

Li, Q.; Jia, T.

2017-09-01

Carbon dioxide emissions from urban road traffic mainly come from automobile exhaust. However, the carbon dioxide emissions obtained by the instruments are unreliable due to time delay error. In order to improve the reliability of data, we propose a method to correct the measured vehicles' carbon dioxide emissions from instrument based on the CMEM model. Firstly, the synthetic time series of carbon dioxide emissions are simulated by CMEM model and GPS velocity data. Then, taking the simulation data as the control group, the time delay error of the measured carbon dioxide emissions can be estimated by the asynchronous correlation analysis, and the outliers can be automatically identified and corrected using the principle of DTW algorithm. Taking the taxi trajectory data of Wuhan as an example, the results show that (1) the correlation coefficient between the measured data and the control group data can be improved from 0.52 to 0.59 by mitigating the systematic time delay error. Furthermore, by adjusting the outliers which account for 4.73 % of the total data, the correlation coefficient can raise to 0.63, which suggests strong correlation. The construction of low carbon traffic has become the focus of the local government. In order to respond to the slogan of energy saving and emission reduction, the distribution of carbon emissions from motor vehicle exhaust emission was studied. So our corrected data can be used to make further air quality analysis.

Influence of Self-emissions on a Mobile Laboratory and Implications for Urban Sampling

NASA Astrophysics Data System (ADS)

Wendt, L. P.

2017-12-01

The importance of urban systems as a large source of greenhouse gases has led to an increase in ground-based campaigns designed to identify and quantify sources. However, plume emissions from vehicle tailpipes can affect emissions for a stationary vehicle or if a tailwind lofts the plume over the car particularly in an urban canyons where wind flow is constrained [1]. Advances in battery technology allow for electric vehicles to sample without self-emissions. Chevrolet has released the Bolt with an estimated range of 238 miles per charge. We are designing a mobile lab using a Chevrolet Bolt with the sensors 5 ft above the ground to reduce drag. Here we investigate the occurrence of self-emissions from a gasoline mobile laboratory set-up that has been optimized to reduce self-emissions and the potential benefits of switching to an electric vehicle for urban sampling. A 2002 Toyota Sienna van and a Licor 7500 CO2/H2O analyzer were deployed to quantify self-emissions. A custom-designed rack elevated the sensors to a height of 8 feet above the tailpipe to minimize self-emission samples [1]. Emissions were sampled over 5 intervals near a relatively isolated field with the van oriented in five directions. A south-easterly wind ( 131o) provided a self-sample opportunity by orienting the car with the tailpipe between the oncoming wind and the sensors. Over 1.5 hours of measurement, 7.8 % of CO2 measurements exceeded 420 ppmv. Of these, four possible self-sample events were observed, or less than 1% with other enhancements attributed to passing cars. These were observed in mild wind conditions averaging 2.8 m/s and only with the tail pipe directly facing into the wind. Results suggest that self-sampling is small in an environment with mild sustained winds and open surroundings. Given the challenge of identifying self-emissions in an isolated environment, urban self-sampling could impact the overall sample especially as these signals may be hard to distinguish from the sources of interest. 1. L. Tao, K. Sun, D. Miller, D. Pan, L. Golston, M. Zondlo, Low power, open-path mobile sensing platform for high-resolution measurements of greenhouse gases and air pollutant, Applied Physics B (2015) 119:153-164s

Impacts of Aging Emission Control Systems on In-Use Heavy-Duty Diesel Truck Emission Rates

NASA Astrophysics Data System (ADS)

Preble, C.; Cados, T.; Harley, R.; Kirchstetter, T.

2017-12-01

Heavy-duty diesel trucks are a major source of nitrogen oxides (NOx) and black carbon (BC) in urban environments, contributing to persistent ozone and particulate matter air quality problems. Recently, diesel particle filter (DPF) and selective catalytic reduction (SCR) emission control systems have become standard equipment on new trucks. Particle filters can also be installed as a retrofit on older engines. Prior work has shown that exhaust filters and SCR systems effectively reduce BC and NOx emission rates by up to 90 and 80%, respectively (Preble et al., ES&T 2015). There is concern, however, that DPFs may promote the formation of ultrafine particles (UFP) and increase tailpipe emissions of nitrogen dioxide (NO2). Additionally, urea-based SCR systems for NOx control may form nitrous oxide (N2O), an important contributor to stratospheric ozone depletion. The effectiveness of these emission controls has been thoroughly evaluated in the laboratory, but the long-term durability of in-use systems and their impacts on co-emitted species have not been well characterized. To evaluate the in-use performance of DPF and SCR systems, pollutant emissions from thousands of diesel trucks were measured over several years at the Port of Oakland and the Caldecott Tunnel in the San Francisco Bay Area. Pollutants present in the exhaust plumes of individual trucks were measured at high time resolution (≥1 Hz) as trucks passed under a mobile lab stationed on an overpass. Fuel-based emission factors (g pollutant emitted per kg fuel burned) were calculated for individual trucks and linked via recorded license plates to vehicle attributes, including engine model year and installed emission control systems. Use of DPFs reduced the BC emission rate by up to 95% at both locations. SCR systems were more effective at reducing NOx emissions under the uphill, highway driving conditions at the Caldecott Tunnel. The emission rates of co-emitted species NO2, UFP, and N2O depended on driving mode. Some DPFs on trucks with 2007-2009 model year engines showed deterioration or failure in filter performance, leading to higher BC emission rates compared to the average for trucks without filters. Emission inventories may underestimate total on-road emissions from diesel trucks, especially if particle filter failure rates continue to increase over time.

Assessing the Gap Between Top-down and Bottom-up Measured Methane Emissions in Indianapolis, IN.

NASA Astrophysics Data System (ADS)

Prasad, K.; Lamb, B. K.; Cambaliza, M. O. L.; Shepson, P. B.; Stirm, B. H.; Salmon, O. E.; Lavoie, T. N.; Lauvaux, T.; Ferrara, T.; Howard, T.; Edburg, S. L.; Whetstone, J. R.

2014-12-01

Releases of methane (CH4) from the natural gas supply chain in the United States account for approximately 30% of the total US CH4 emissions. However, there continues to be large questions regarding the accuracy of current emission inventories for methane emissions from natural gas usage. In this paper, we describe results from top-down and bottom-up measurements of methane emissions from the large isolated city of Indianapolis. The top-down results are based on aircraft mass balance and tower based inverse modeling methods, while the bottom-up results are based on direct component sampling at metering and regulating stations, surface enclosure measurements of surveyed pipeline leaks, and tracer/modeling methods for other urban sources. Mobile mapping of methane urban concentrations was also used to identify significant sources and to show an urban-wide low level enhancement of methane levels. The residual difference between top-down and bottom-up measured emissions is large and cannot be fully explained in terms of the uncertainties in top-down and bottom-up emission measurements and estimates. Thus, the residual appears to be, at least partly, attributed to a significant wide-spread diffusive source. Analyses are included to estimate the size and nature of this diffusive source.

In-vitro and In-vivo approaches for the measurement of oral bioavailability of lead (Pb) in soil: A critical review

USDA-ARS?s Scientific Manuscript database

Urban soils are commonly contaminated by Pb and some other elements from house paint, automotive emissions, and general urban emissions. Soil Pb near painted houses can exceed 10,000 mg/kg, while commonly ranging from 500 to 1000 mg/kg. Such high soil Pb levels raise concerns about exposure of chi...

CO2 Urban Synthesis and Analysis ("CO2-USA") Network

NASA Astrophysics Data System (ADS)

Lin, J. C.; Hutyra, L.; Loughner, C.; Stein, A. F.; Lusk, K.; Mitchell, L.; Gately, C.; Wofsy, S. C.

2017-12-01

Emissions of carbon associated with cities comprise a large component of the anthropogenic source. A number of cities have announced plans to reduce greenhouse gas emissions, but the scientific knowledge to quantitatively track emissions and assess the efficacy of mitigation is lacking. As the global population increasingly resides in urban regions, scientific knowledge about how much, where, and why a particular city emits carbon becomes increasingly important. To address this gap, researchers have initiated studies of carbon emissions and cycling in several U.S. cities, making it timely to develop a collaborative network to exchange information on community standards and common measurements, facilitate data sharing, and create analysis frameworks and cross-city syntheses to catalyze a new generation of researchers and enable new collaborations tackling important objectives that are difficult to address in isolation. We describe initial results from an incipient network focusing initially on cities in the U.S. with low barriers of entry that entrains a cross-section of U.S. urban centers with varying characteristics: size, population density, vegetation, urban form, infrastructure, development rates, climate, and meteorological patterns. Results will be reported that emerge from an initial workshop covering data harmonization & integration, inventory comparison, stakeholder outreach, network design, inverse modeling, and collaboration.

Modelling the Contribution of Long-range Transport of Ammonium Nitrates to Urban Air Pollution and Human Exposure in the United Kingdom

NASA Astrophysics Data System (ADS)

Reis, S.; Vieno, M.; Beck, R.; Ots, R.; Moring, A.; Steinle, S.; Heal, M. R.; Doherty, R. M.

2014-12-01

Urban air pollution and its effects on human health remain to be a challenge in spite of substantial reductions in the emissions of air pollutants (e.g. sulphur dioxide, nitrogen oxides) over the past decades in Europe. While primary pollutants play a vital role in urban air pollution, recent model studies highlight and quantify the relevance of long-range transport of secondary pollution (e.g. secondary inorganic aerosols such as ammonium sulphates and nitrates, or ground level ozone) for the exceedance of local air quality limit values in urban areas across Europe. This contribution can be seen in recurring episodes, for instance in spring 2014, with very high levels of fine particulate matter (PM2.5) in Paris, London and other European cities, as well as in elevated background levels throughout the year. While we will focus on the contribution to exceedances of PM2.5 limit values here, this transboundary transport has wider implications for the deposition of reactive nitrogen far from the source as well. As local authorities are tasked with ensuring the attainment of air quality limit values, exceedances caused by long-range transport, with emissions originating from sources outside of their jurisdiction present substantial challenges. Furthermore, while policy measures have successfully addressed emissions from large point sources in the past, and made progress towards reducing pollution from road vehicles, emissions of ammonia from agricultural sources - a key component for the long-range transport of secondary inorganic aerosols - have remained relatively stable in Europe. Using the example of Europe and the UK, we demonstrate in our presentation how atmospheric chemistry transport modelling across different scales (from regional to local) can provide vital insight in the mechanisms of and relative contributions to the formation of secondary inorganic aerosols. In addition, we illustrate how this modelling capability can inform the design of efficient control strategies by quantifying the effect of different policy measures targeted at specific source sectors, and highlight the role of transboundary air pollution to local air pollution challenges.

Urban ecosystems and the North American carbon cycle

Treesearch

D.E. Pataki; R.J. Alig; A.S. Fung; N.E. Golubiewski; C.A. Kennedy; E.G. McPherson; D.J. Nowak; R.V. Pouyat; P.R. Lankao

2006-01-01

Approximately 75–80% of the population of North America currently lives in urban areas as defined by national census bureaus, and urbanization is continuing to increase. Future trajectories of fossil fuel emissions are associated with a high degree of uncertainty; however, if the activities of urban residents and the rate of urban land conversion can be captured in...

Urbanization and its implications for food and farming.

PubMed

Satterthwaite, David; McGranahan, Gordon; Tacoli, Cecilia

2010-09-27

This paper discusses the influences on food and farming of an increasingly urbanized world and a declining ratio of food producers to food consumers. Urbanization has been underpinned by the rapid growth in the world economy and in the proportion of gross world product and of workers in industrial and service enterprises. Globally, agriculture has met the demands from this rapidly growing urban population, including food that is more energy-, land-, water- and greenhouse gas emission-intensive. But hundreds of millions of urban dwellers suffer under-nutrition. So the key issues with regard to agriculture and urbanization are whether the growing and changing demands for agricultural products from growing urban populations can be sustained while at the same time underpinning agricultural prosperity and reducing rural and urban poverty. To this are added the need to reduce greenhouse gas emissions and to build resilience in agriculture and urban development to climate change impacts. The paper gives particular attention to low- and middle-income nations since these have more than three-quarters of the world's urban population and most of its largest cities and these include nations where issues of food security are most pressing.

Emission characteristics of atmospheric carbon dioxide in Xi'an, China based on the measurements of CO2 concentration, △14C and δ13C.

PubMed

Wang, Peng; Zhou, Weijian; Niu, Zhenchuan; Cheng, Peng; Wu, Shugang; Xiong, Xiaohu; Lu, Xuefeng; Du, Hua

2018-04-01

Given that cities contributed most of China's CO 2 emissions, understanding the emission characteristics of urban atmospheric CO 2 is critical for regulating CO 2 emissions. Regular observations of atmospheric CO 2 concentration, △ 14 C and δ 13 C values were performed at four different sites in Xi'an, China in 2016 to illustrate the temporal and spatial variations of CO 2 emissions and recognize their sources and sinks in urban carbon cycles. We found seasonal variations in CO 2 concentration and δ 13 C values, the peak to peak amplitude of which was 80.8ppm for CO 2 concentration and 4.0‰ for its δ 13 C. With regard to the spatial variations, the urban CO 2 "dome" effect was the most pronounced during the winter season. The use of △ 14 C combines with δ 13 C measurements aid in understanding the emission patterns. The results show that in the winter season, emissions from fossil fuel derived CO 2 (CO 2ff ) contributed 61.8±10.6% and 57.4±9.7% of the excess CO 2 (CO 2ex ) in urban and suburban areas respectively. Combining with the result of estimated δ 13 C value of fossil fuel (δ 13 C ff =-24‰), which suggest coal burning was the dominant source of fossil fuel emissions. In contrast, the proportions of CO 2ff in CO 2ex varied more in the summer season than that in the winter season, ranging from 42.3% to >100% with the average contributions of 82.5±23.8% and 90.0±24.8%. Given the estimation of δ 13 C value of local sources (δ 13 C s ) was -21.9‰ indicates that the intensively biogenic activities, such as soil respiration and corn growth have significantly impacted urban carbon cycles, and occasionally played a role of carbon sink. Copyright © 2017 Elsevier B.V. All rights reserved.

Contribution of flowering trees to urban atmospheric biogenic volatile organic compound emissions

NASA Astrophysics Data System (ADS)

Baghi, R.; Helmig, D.; Guenther, A.; Duhl, T.; Daly, R.

2012-03-01

Emissions of biogenic volatile organic compounds (BVOC) from urban trees during and after blooming were measured during spring and early summer 2009 in Boulder, Colorado. Air samples were collected onto solid adsorbent cartridges from branch enclosures on the tree species crabapple, horse chestnut, honey locust, and hawthorn. These species constitute ~65 % of the insect-pollinated fraction of the flowering tree canopy (excluding catkin-producing trees) from the street area managed by the City of Boulder. Samples were analyzed for C10-C15 BVOC by thermal desorption and gas chromatography coupled to a flame ionization detector and a mass spectrometer (GC/FID/MS). Identified emissions and emission rates from these four tree species during the flowering phase were found to vary over a wide range. Monoterpene emissions were identified for honey locust, horse chestnut and hawthorn. Sesquiterpene emissions were observed in horse chestnut and hawthorn samples. Crabapple flowers were found to emit significant amounts of benzyl alcohol and benzaldehyde. Floral BVOC emissions increased with temperature, generally exhibiting exponential temperature dependence. Changes in BVOC speciation during and after the flowering period were observed for every tree studied. Emission rates were significantly higher during the blooming compared to the vegetative state for crabapple and honey locust. Total normalized (30 °C) monoterpene emissions from honey locust were higher during flowering (5.26 μg Cg-1 h-1) than after flowering (1.23 μg Cg-1 h-1). The total normalized BVOC emission rate from crabapple (93 μg Cg-1 h-1) during the flowering period is of the same order as isoprene emissions from oak trees, which are among the highest BVOC emissions observed from plants to date. These findings illustrate that during the relatively brief springtime flowering period, floral emissions constitute by far the most significant contribution to the BVOC flux from these tree species, some of which are leafless at this time. Experimental results were integrated into the MEGAN biogenic emission model and simulations were performed to estimate the contribution of floral BVOC emissions to the total urban BVOC flux during the spring flowering period. The floral BVOC emitted during this three-month simulation are equivalent to 11 % of the cumulative monoterpene flux for the Boulder urban area.

Contribution of flowering trees to urban atmospheric biogenic volatile organic compound emissions

NASA Astrophysics Data System (ADS)

Baghi, R.; Helmig, D.; Guenther, A.; Duhl, T.; Daly, R.

2012-04-01

Emissions of biogenic volatile organic compounds (BVOC) from urban trees during and after blooming were measured during spring and early summer 2009 in Boulder, Colorado. Air samples were collected onto solid adsorbent cartridges from branch enclosures on the following trees: crabapple, horse chestnut, honey locust and hawthorn. These species constitute ~65% of the insect-pollinated fraction of the flowering tree canopy (excluding catkin-producing trees) from the total street area managed by the City of Boulder. Samples were subsequently analyzed for C10 - C15 BVOC by thermal desorption and gas chromatography coupled to a flame ionization detector and a mass spectrometer (GC/FID/MS). Identified emissions and emission rates from these four tree species during the flowering phase were found to vary over a wide range. Monoterpene emissions were identified for honey locust, horse chestnut and hawthorn. Sesquiterpene emissions were observed in horse chestnut and hawthorn samples. Crabapple flowers were found to emit significant amounts of benzyl alcohol and benzaldehyde. Floral BVOC emissions were found to increase with temperature, generally exhibiting exponential temperature dependence. Changes in BVOC speciation during and after the flowering period were observed for every tree studied. Emission rates were significantly higher during the blooming compared to the vegetative state for crabapple and honey locust. Total normalized (30oC) monoterpene emissions from honey locust were 4.3 fold higher during flowering (5.26 μgC g-1h-1) than after flowering (1.23 μgC g-1h-1). The total normalized BVOC emission rate from crabapple (93 μgC g-1h-1) during the flowering period is of the same order as isoprene emissions from oak trees, which are among the highest BVOC emissions observed to date. These findings illustrate that during the relatively brief springtime flowering period, floral emissions constitute by far the most significant contribution to the BVOC flux from these tree species, some of which are leafless at this time. These experimental results were integrated into the MEGAN biogenic emission model and simulations were performed to estimate the contribution of floral BVOC emissions to the total urban BVOC flux during the spring flowering period. The floral BVOC emitted during this three-month simulation constitute eleven percent of the cumulative monoterpene flux for the Boulder urban area.

Large Uncertainties in Urban-Scale Carbon Emissions

NASA Astrophysics Data System (ADS)

Gately, C. K.; Hutyra, L. R.

2017-10-01

Accurate estimates of fossil fuel carbon dioxide (FFCO2) emissions are a critical component of local, regional, and global climate agreements. Current global inventories of FFCO2 emissions do not directly quantify emissions at local scales; instead, spatial proxies like population density, nighttime lights, and power plant databases are used to downscale emissions from national totals. We have developed a high-resolution (hourly, 1 km2) bottom-up Anthropogenic Carbon Emissions System (ACES) for FFCO2, based on local activity data for the year 2011 across the northeastern U.S. We compare ACES with three widely used global inventories, finding significant differences at regional (20%) and city scales (50-250%). At a spatial resolution of 0.1°, inventories differ by over 100% for half of the grid cells in the domain, with the largest differences in urban areas and oil and gas production regions. Given recent U.S. federal policy pull backs regarding greenhouse gas emissions reductions, inventories like ACES are crucial for U.S. actions, as the impetus for climate leadership has shifted to city and state governments. The development of a robust carbon monitoring system to track carbon fluxes is critical for emissions benchmarking and verification. We show that existing downscaled inventories are not suitable for urban emissions monitoring, as they do not consider important local activity patterns. The ACES methodology is designed for easy updating, making it suitable for emissions monitoring under most city, regional, and state greenhouse gas mitigation initiatives, in particular, for the small- and medium-sized cities that lack the resources to regularly perform their own bottom-up emissions inventories.

Carbon footprints of cities and other human settlements in the UK

NASA Astrophysics Data System (ADS)

Minx, Jan; Baiocchi, Giovanni; Wiedmann, Thomas; Barrett, John; Creutzig, Felix; Feng, Kuishuang; Förster, Michael; Pichler, Peter-Paul; Weisz, Helga; Hubacek, Klaus

2013-09-01

A growing body of literature discusses the CO2 emissions of cities. Still, little is known about emission patterns across density gradients from remote rural places to highly urbanized areas, the drivers behind those emission patterns and the global emissions triggered by consumption in human settlements—referred to here as the carbon footprint. In this letter we use a hybrid method for estimating the carbon footprints of cities and other human settlements in the UK explicitly linking global supply chains to local consumption activities and associated lifestyles. This analysis comprises all areas in the UK, whether rural or urban. We compare our consumption-based results with extended territorial CO2 emission estimates and analyse the driving forces that determine the carbon footprint of human settlements in the UK. Our results show that 90% of the human settlements in the UK are net importers of CO2 emissions. Consumption-based CO2 emissions are much more homogeneous than extended territorial emissions. Both the highest and lowest carbon footprints can be found in urban areas, but the carbon footprint is consistently higher relative to extended territorial CO2 emissions in urban as opposed to rural settlement types. The impact of high or low density living remains limited; instead, carbon footprints can be comparatively high or low across density gradients depending on the location-specific socio-demographic, infrastructural and geographic characteristics of the area under consideration. We show that the carbon footprint of cities and other human settlements in the UK is mainly determined by socio-economic rather than geographic and infrastructural drivers at the spatial aggregation of our analysis. It increases with growing income, education and car ownership as well as decreasing household size. Income is not more important than most other socio-economic determinants of the carbon footprint. Possibly, the relationship between lifestyles and infrastructure only impacts carbon footprints significantly at higher spatial granularity.

The potential impacts of electric vehicles on air quality in the urban areas of Barcelona and Madrid (Spain)

NASA Astrophysics Data System (ADS)

Soret, A.; Guevara, M.; Baldasano, J. M.

2014-12-01

This work analyses the potential air quality improvements resulting from three fleet electrification scenarios (∼13, 26 and 40%) by replacing conventional vehicles with Electric Battery Vehicles (EBVs), Plug-in Hybrid Electric Vehicles (PHEVs) and Hybrid Electric Vehicles (HEVs). This study has been performed for the cities of Barcelona and Madrid (Spain), where road transport is the primary emission source. In these urban areas, several air quality problems are present, mainly related to NO2 and particulate matter. The WRF-ARW/HERMESv2/CMAQ model system has been applied at high spatial (1 × 1 km2) and temporal (1 h) resolution. The results show that fleet electrification offers a potential for emission abatement, especially related to NOx and CO. Regarding the more ambitious scenario (∼40% fleet electrification), reductions of 11% and 17% of the total NOx emissions are observed in Barcelona and Madrid respectively. These emissions reductions involve air quality improvements in NO2 maximum hourly values up to 16%: reductions up to 30 and 35 μg m-3 in Barcelona and Madrid, respectively. Furthermore, an additional scenario has been defined considering electric generation emissions associated with EBVs and PHEVs charging from a combined-cycle power plant. These charging emissions would produce slight NO2 increases in the downwind areas of <3 μg m-3. Thus, fleet electrification would improve urban air quality even when considering emissions associated with charging electric vehicles. However, two further points should be considered. First, fleet electrification cannot be considered a unique solution, and other management strategies may be defined. This is especially important with respect to particulate matter emissions, which are not significantly reduced by fleet electrification (<5%) due to the high weight of non-exhaust emissions. Second, a significant introduction of electric vehicles (26-40%) involving all vehicle categories is required to improve urban air quality.

Toward a Multi-City Framework for Urban GHG Estimation in the United States: Methods, Uncertainties, and Future Goals

NASA Astrophysics Data System (ADS)

Mueller, K. L.; Callahan, W.; Davis, K. J.; Dickerson, R. R.; Duren, R. M.; Gurney, K. R.; Karion, A.; Keeling, R. F.; Kim, J.; Lauvaux, T.; Miller, C. E.; Shepson, P. B.; Turnbull, J. C.; Weiss, R. F.; Whetstone, J. R.

2017-12-01

City and State governments are increasingly interested in mitigating greenhouse gas (GHG) emissions to improve sustainability within their jurisdictions. Estimation of urban GHG emissions remains an active research area with many sources of uncertainty. To support the effort of improving measurement of trace gas emissions in city environments, several federal agencies along with academic, research, and private entities have been working within a handful of domestic metropolitan areas to improve both (1) the assessment of GHG emissions accuracy using a variety of measurement technologies, and (2) the tools that can better assess GHG inventory data at urban mitigation scales based upon these measurements. The National Institute of Standards and Technology (NIST) activities have focused on three areas, or testbeds: Indianapolis (INFLUX experiment), Los Angeles (the LA Megacities project), and the Northeastern Corridor areas encompassing Washington and Baltimore (the NEC/BW GHG Measurements project). These cities represent diverse meteorological, terrain, demographic, and emissions characteristics having a broad range of complexities. To date this research has involved multiple measurement systems and integrated observing approaches, all aimed at advancing development of a robust, science-base upon which higher accuracy quantification approaches can rest. Progress toward such scientifically robust, widely-accepted emissions quantification methods will rely upon continuous performance assessment. Such assessment is challenged by the complexities of cities themselves (e.g., population, urban form) along with the many variables impacting a city's technological ability to estimate its GHG emissions (e.g., meteorology, density of observations). We present the different NIST testbeds and a proposal to initiate conceptual development of a reference framework supporting the comparison of multi-city GHG emissions estimates. Such a reference framework has potential to provide the basis for city governments to choose the measurements and methods that can quantify their GHG and related trace gas emissions at levels commensurate with their needs.

Waste management activities and carbon emissions in Africa.

PubMed

Couth, R; Trois, C

2011-01-01

This paper summarizes research into waste management activities and carbon emissions from territories in sub-Saharan Africa with the main objective of quantifying emission reductions (ERs) that can be gained through viable improvements to waste management in Africa. It demonstrates that data on waste and carbon emissions is poor and generally inadequate for prediction models. The paper shows that the amount of waste produced and its composition are linked to national Gross Domestic Product (GDP). Waste production per person is around half that in developed countries with a mean around 230 kg/hd/yr. Sub-Saharan territories produce waste with a biogenic carbon content of around 56% (+/-25%), which is approximately 40% greater than developed countries. This waste is disposed in uncontrolled dumps that produce large amounts of methane gas. Greenhouse gas (GHG) emissions from waste will rise with increasing urbanization and can only be controlled through funding mechanisms from developed countries. Copyright © 2010 Elsevier Ltd. All rights reserved.

Growing cooler : the evidence on urban development and climate change

DOT National Transportation Integrated Search

1997-10-01

This new book documents how key changes in land development patterns could help reduce vehicle : greenhouse gas emissions. Based on a comprehensive review of dozens of studies by leading urban : planning researchers, the book concludes that urban dev...

Estimating the health benefits from natural gas use in transport and heating in Santiago, Chile.

PubMed

Mena-Carrasco, Marcelo; Oliva, Estefania; Saide, Pablo; Spak, Scott N; de la Maza, Cristóbal; Osses, Mauricio; Tolvett, Sebastián; Campbell, J Elliott; Tsao, Tsao Es Chi-Chung; Molina, Luisa T

2012-07-01

Chilean law requires the assessment of air pollution control strategies for their costs and benefits. Here we employ an online weather and chemical transport model, WRF-Chem, and a gridded population density map, LANDSCAN, to estimate changes in fine particle pollution exposure, health benefits, and economic valuation for two emission reduction strategies based on increasing the use of compressed natural gas (CNG) in Santiago, Chile. The first scenario, switching to a CNG public transportation system, would reduce urban PM2.5 emissions by 229 t/year. The second scenario would reduce wood burning emissions by 671 t/year, with unique hourly emission reductions distributed from daily heating demand. The CNG bus scenario reduces annual PM2.5 by 0.33 μg/m³ and up to 2 μg/m³ during winter months, while the residential heating scenario reduces annual PM2.5 by 2.07 μg/m³, with peaks exceeding 8 μg/m³ during strong air pollution episodes in winter months. These ambient pollution reductions lead to 36 avoided premature mortalities for the CNG bus scenario, and 229 for the CNG heating scenario. Both policies are shown to be cost-effective ways of reducing air pollution, as they target high-emitting area pollution sources and reduce concentrations over densely populated urban areas as well as less dense areas outside the city limits. Unlike the concentration rollback methods commonly used in public policy analyses, which assume homogeneous reductions across a whole city (including homogeneous population densities), and without accounting for the seasonality of certain emissions, this approach accounts for both seasonality and diurnal emission profiles for both the transportation and residential heating sectors. Copyright © 2012 Elsevier B.V. All rights reserved.

City-level variations in NOx emissions derived from hourly monitoring data in Chicago

NASA Astrophysics Data System (ADS)

de Foy, Benjamin

2018-03-01

Control on emissions of nitrogen oxides (NOx) in the United States of America have led to reductions in concentrations in urban areas by up to a factor of two in the last decade. The Air Quality System monitoring network provides surface measurements of concentrations at hourly resolution over multiple years, revealing variations at the annual, seasonal, day of week and diurnal time scales. A multiple linear regression model was used to estimate the temporal profiles in the NOx concentrations as well as the impact of meteorology, ozone concentrations, and boundary layer heights. The model is applied to data from 2005 to 2016 available at 6 sites in Chicago, Illinois. Results confirm the 50% decrease in NOx over the length of the time series. The weekend effect is found to be stronger in more commercial areas, with 32% reductions on Saturdays and 45% on Sundays and holidays; and weaker in more residential areas with 20% reductions on Saturdays and 30% reductions on Sundays. Weekday diurnal profiles follow a double hump with emission peaks during the morning and afternoon rush hours, but only a shallow drop during the middle day. Difference in profiles from the 6 sites suggest that there are different emission profiles within the urban area. Diurnal profiles on Saturdays have less variation throughout the day and more emissions in the evening. Sundays are very different from both weekdays and Saturdays with a gradual increase until the early evening. The results suggest that in addition to vehicle type and vehicle miles traveled, vehicle speed and congestion must be taken into account to correctly quantify morning rush hour emissions and the weekend effect.

Assessment of uncertainties of an aircraft-based mass balance approach for quantifying urban greenhouse gas emissions

NASA Astrophysics Data System (ADS)

Cambaliza, M. O. L.; Shepson, P. B.; Caulton, D. R.; Stirm, B.; Samarov, D.; Gurney, K. R.; Turnbull, J.; Davis, K. J.; Possolo, A.; Karion, A.; Sweeney, C.; Moser, B.; Hendricks, A.; Lauvaux, T.; Mays, K.; Whetstone, J.; Huang, J.; Razlivanov, I.; Miles, N. L.; Richardson, S. J.

2014-09-01

Urban environments are the primary contributors to global anthropogenic carbon emissions. Because much of the growth in CO2 emissions will originate from cities, there is a need to develop, assess, and improve measurement and modeling strategies for quantifying and monitoring greenhouse gas emissions from large urban centers. In this study the uncertainties in an aircraft-based mass balance approach for quantifying carbon dioxide and methane emissions from an urban environment, focusing on Indianapolis, IN, USA, are described. The relatively level terrain of Indianapolis facilitated the application of mean wind fields in the mass balance approach. We investigate the uncertainties in our aircraft-based mass balance approach by (1) assessing the sensitivity of the measured flux to important measurement and analysis parameters including wind speed, background CO2 and CH4, boundary layer depth, and interpolation technique, and (2) determining the flux at two or more downwind distances from a point or area source (with relatively large source strengths such as solid waste facilities and a power generating station) in rapid succession, assuming that the emission flux is constant. When we quantify the precision in the approach by comparing the estimated emissions derived from measurements at two or more downwind distances from an area or point source, we find that the minimum and maximum repeatability were 12 and 52%, with an average of 31%. We suggest that improvements in the experimental design can be achieved by careful determination of the background concentration, monitoring the evolution of the boundary layer through the measurement period, and increasing the number of downwind horizontal transect measurements at multiple altitudes within the boundary layer.

Isotopic evidence for enhanced fossil fuel sources of aerosol ammonium in the urban atmosphere.

PubMed

Pan, Yuepeng; Tian, Shili; Liu, Dongwei; Fang, Yunting; Zhu, Xiaying; Gao, Meng; Gao, Jian; Michalski, Greg; Wang, Yuesi

2018-07-01

The sources of aerosol ammonium (NH 4 + ) are of interest because of the potential of NH 4 + to impact the Earth's radiative balance, as well as human health and biological diversity. Isotopic source apportionment of aerosol NH 4 + is challenging in the urban atmosphere, which has excess ammonia (NH 3 ) and where nitrogen isotopic fractionation commonly occurs. Based on year-round isotopic measurements in urban Beijing, we show the source dependence of the isotopic abundance of aerosol NH 4 + , with isotopically light (-33.8‰) and heavy (0 to +12.0‰) NH 4 + associated with strong northerly winds and sustained southerly winds, respectively. On an annual basis, 37-52% of the initial NH 3 concentrations in urban Beijing arises from fossil fuel emissions, which are episodically enhanced by air mass stagnation preceding the passage of cold fronts. These results provide strong evidence for the contribution of non-agricultural sources to NH 3 in urban regions and suggest that priority should be given to controlling these emissions for haze regulation. This study presents a carefully executed application of existing stable nitrogen isotope measurement and mass-balance techniques to a very important problem: understanding source contributions to atmospheric NH 3 in Beijing. This question is crucial to informing environmental policy on reducing particulate matter concentrations, which are some of the highest in the world. However, the isotopic source attribution results presented here still involve a number of uncertain assumptions and they are limited by the incomplete set of chemical and isotopic measurements of gas NH 3 and aerosol NH 4 + . Further field work and lab experiments are required to adequately characterize endmember isotopic signatures and the subsequent isotopic fractionation process under different air pollution and meteorological conditions. Copyright © 2018 Elsevier Ltd. All rights reserved.

Fast Identification of Methane and Other Atmospheric Contaminant Sources in Complex Urban Settings

NASA Astrophysics Data System (ADS)

Jacobson, G. A.; Crosson, E.; Tan, S. M.

2012-12-01

The identification and quantification of greenhouse gas emissions (fluxes) from urban centers have become of increasing interest over the last few years. This interest is driven by recent measurements indicating that urban emissions are a significant source of methane (CH4) and in fact may be substantially higher than current inventory estimates(1). Urban CH4 emissions could contribute 7-15% to the global anthropogenic budget of methane. Although it is known that the per capita carbon footprint of compact cities, such as New York City, Boston, and San Francisco, are smaller than sprawling cities, such as Houston, the strengths of individual sources within these cities are not well known. Such information is of use to policy makers because it can be used to incentivize changes in transportation and land use patterns. The work discussed here will highlight a vehicle-based methodology for characterizing urban emissions that enables extremely fast identification of methane sources in complex urban settings. Measurements were taken while driving at speeds from 20 to 40 miles per hour in stop and go traffic and were able to not only identify methane plumes but in addition, provide information about the location of the sources generating these methane plumes. Results showed that a large number of highly localized methane sources were found in Boston and San Francisco. For example, leaks from natural gas production, transmission and distribution lines were found in both cities. Flux chamber measurements of these leaks indicate that the methane flux ranged from 40 to 300 standard cubic feet of natural gas per day. For reference, the average American home uses approximately 200-300 cubic feet of natural gas per day. These leaks increase cost to natural gas suppliers, add to greenhouse gas concentrations, and in extreme cases pose a safety hazard. In this work, results showing the identification, location, and quantifying methane sources in urban settings will be presented. We will also present how these techniques could be extended for use in further identification of urban emissions, for example, by measuring H2S produced by sewage, landfills or industrial processes. (1) Wunch, D., P.O. Wennberg, G.C. Toon, G. Keppel-Aleks, and Y.G. Yavin, Emissions of Greenhouse Gases from a North American Megacity, Geophysical Research Letters, Vol. 36, L15810, doi:10.1029/2009GL)39825, 2009.; Mobile methane survey results showing how plume signatures can be used to identify natural gas leaks as a source of methane.

Modelling of the urban concentrations of PM2.5 on a high resolution for a period of 35 years, for the assessment of lifetime exposure and health effects

NASA Astrophysics Data System (ADS)

Kukkonen, Jaakko; Kangas, Leena; Kauhaniemi, Mari; Sofiev, Mikhail; Aarnio, Mia; Jaakkola, Jouni J. K.; Kousa, Anu; Karppinen, Ari

2018-06-01

Reliable and self-consistent data on air quality are needed for an extensive period of time for conducting long-term, or even lifetime health impact assessments. We have modelled the urban-scale concentrations of fine particulate matter (PM2.5) in the Helsinki Metropolitan Area for a period of 35 years, from 1980 to 2014. The regional background concentrations were evaluated based on reanalyses of the atmospheric composition on global and European scales, using the SILAM model. The high-resolution urban computations included both the emissions originated from vehicular traffic (separately exhaust and suspension emissions) and those from small-scale combustion, and were conducted using the road network dispersion model CAR-FMI and the multiple-source Gaussian dispersion model UDM-FMI. The modelled concentrations of PM2.5 agreed fairly well with the measured data at a regional background station and at four urban measurement stations, during 1999-2014. The modelled concentration trends were also evaluated for earlier years, until 1988, using proxy analyses. There was no systematic deterioration of the agreement of predictions and data for earlier years (the 1980s and 1990s), compared with the results for more recent years (2000s and early 2010s). The local vehicular emissions were about 5 times higher in the 1980s, compared with the emissions during the latest considered years. The local small-scale combustion emissions increased slightly over time. The highest urban concentrations of PM2.5 occurred in the 1980s; these have since decreased to about to a half of the highest values. In general, regional background was the largest contribution in this area. Vehicular exhaust has been the most important local source, but the relative shares of both small-scale combustion and vehicular non-exhaust emissions have increased in time. The study has provided long-term, high-resolution concentration databases on regional and urban scales that can be used for the assessment of health effects associated with air pollution.

Radiocarbon Records of Fossil Fuel Emissions From Urban Trees in the Greater Salt Lake Valley From Mid-Century to Present.

NASA Astrophysics Data System (ADS)

Chritz, K.; Buchert, M.; Walker, J. C.; Mendoza, D.; Pataki, D. E.; Xu, X.; Lin, J. C.

2017-12-01

Generating long term records of fossil fuel emissions of urban environments is complicated by the fact that direct observations of emissions and urban atmospheric CO2 concentrations were only collected in the recent past. Radiocarbon (14C) in tree rings from urban trees can provide archives of fossil fuel emissions that may track population growth over time, as higher population density is typically correlated with increased vehicular traffic and associated CO2 emissions, which are radiocarbon dead. We present radiocarbon measurements (n=125) from five roadside green ash trees (Fraxinus pennsylvanica) located in three cities of northern Utah - Salt Lake City (urban, 2016 population: 193,744), Logan City (agricultural, 2016 population: 49,110) and Heber (rural, 2016 population: 14,969). Urban trees were cored in four cardinal directions and ring widths were measured and counted to establish a chronology. One ring from every third year in a single core from each tree was removed and holocellulose was extracted from bulk wood of individual rings for 14C analysis. Fraction CO2 from fossil fuel burning (CO2-ff) was calculated using a simple mass-balance calculation from measured 14C values and remote background atmospheric 14CO2 values for NH Zone 2. The data from all three cities indicate a general trend of increasing CO2-ff uptake by the trees from 1980s to present, as expected with increased population growth and vehicular traffic. However, records in all three cities show unique elevated CO2-ff prior to the 1980s, assuming similar climate patterns through time, diverging from historic population size. We employed atmospheric simulations from the STILT (Stochastic Time-Inverted Lagrangian Transport) models for each of these trees to create footprints to determine source areas for CO2. These footprints reveal that atmospheric sampling areas can be large for certain trees, and other sources of 14C dead carbon, such as coal and natural gas from industrial emissions, should also be considered when building these records.

Primary and secondary sources of formaldehyde in urban atmospheres: Houston Texas region

NASA Astrophysics Data System (ADS)

Parrish, D. D.; Ryerson, T. B.; Mellqvist, J.; Johansson, J.; Fried, A.; Richter, D.; Walega, J. G.; Washenfelder, R. A.; de Gouw, J. A.; Peischl, J.; Aikin, K. C.; McKeen, S. A.; Frost, G. J.; Fehsenfeld, F. C.; Herndon, S. C.

2011-12-01

We evaluate the rates of secondary production and primary emission of formaldehyde (CH2O) from petrochemical industrial facilities and on-road vehicles in the Houston Texas region. This evaluation is based upon ambient measurements collected during field studies in 2000, 2006 and 2009. The predominant CH2O source (92 ± 4% of total) is secondary production formed during the atmospheric oxidation of highly reactive volatile organic compounds (HRVOCs) emitted from the petrochemical facilities. Smaller contributions are primary emissions from these facilities (4 ± 2%), and secondary production (~3%) and primary emissions (~1%) from vehicles. The primary emissions from both sectors are well quantified by current emission inventories. Since secondary production dominates, control efforts directed at primary CH2O emissions cannot address the large majority of CH2O sources in the Houston area, although there may still be a role for such efforts. Ongoing efforts to control alkene emissions from the petrochemical facilities, as well as volatile organic compound emissions from the motor vehicle fleet, will effectively reduce the CH2O concentrations in the Houston region. We have not addressed other emission sectors, such as off-road mobile sources or secondary formation from biogenic hydrocarbons. Previous analyses based on correlations between ambient concentrations of CH2O and various marker species have suggested much larger primary emissions of CH2O, but those results neglect confounding effects of dilution and loss processes, and do not demonstrate the causes of the observed correlations. Similar problems must be suspected in any source apportionment analysis of secondary species based upon correlations of ambient concentrations of pollutants.

Primary and secondary sources of formaldehyde in urban atmospheres: Houston Texas region

NASA Astrophysics Data System (ADS)

Parrish, D. D.; Ryerson, T. B.; Mellqvist, J.; Johansson, J.; Fried, A.; Richter, D.; Walega, J. G.; Washenfelder, R. A.; de Gouw, J. A.; Peischl, J.; Aikin, K. C.; McKeen, S. A.; Frost, G. J.; Fehsenfeld, F. C.; Herndon, S. C.

2012-04-01

We evaluate the rates of secondary production and primary emission of formaldehyde (CH2O) from petrochemical industrial facilities and on-road vehicles in the Houston Texas region. This evaluation is based upon ambient measurements collected during field studies in 2000, 2006 and 2009. The predominant CH2O source (92 ± 4% of total) is secondary production formed during the atmospheric oxidation of highly reactive volatile organic compounds (HRVOCs) emitted from the petrochemical facilities. Smaller contributions are primary emissions from these facilities (4 ± 2%), and secondary production (~3%) and primary emissions (~1%) from vehicles. The primary emissions from both sectors are well quantified by current emission inventories. Since secondary production dominates, control efforts directed at primary CH2O emissions cannot address the large majority of CH2O sources in the Houston area, although there may still be a role for such efforts. Ongoing efforts to control alkene emissions from the petrochemical facilities, as well as volatile organic compound emissions from the motor vehicle fleet, will effectively reduce the CH2O concentrations in the Houston region. We do not address other emission sectors, such as off-road mobile sources or secondary formation from biogenic hydrocarbons. Previous analyses based on correlations between ambient concentrations of CH2O and various marker species have suggested much larger primary emissions of CH2O, but those results neglect confounding effects of dilution and loss processes, and do not demonstrate the causes of the observed correlations. Similar problems must be suspected in any source apportionment analysis of secondary species based upon correlations of ambient concentrations of pollutants.

[Quantitative estimation source of urban atmospheric CO2 by carbon isotope composition].

PubMed

Liu, Wei; Wei, Nan-Nan; Wang, Guang-Hua; Yao, Jian; Zeng, You-Shi; Fan, Xue-Bo; Geng, Yan-Hong; Li, Yan

2012-04-01

To effectively reduce urban carbon emissions and verify the effectiveness of currently project for urban carbon emission reduction, quantitative estimation sources of urban atmospheric CO2 correctly is necessary. Since little fractionation of carbon isotope exists in the transportation from pollution sources to the receptor, the carbon isotope composition can be used for source apportionment. In the present study, a method was established to quantitatively estimate the source of urban atmospheric CO2 by the carbon isotope composition. Both diurnal and height variations of concentrations of CO2 derived from biomass, vehicle exhaust and coal burning were further determined for atmospheric CO2 in Jiading district of Shanghai. Biomass-derived CO2 accounts for the largest portion of atmospheric CO2. The concentrations of CO2 derived from the coal burning are larger in the night-time (00:00, 04:00 and 20:00) than in the daytime (08:00, 12:00 and 16:00), and increase with the increase of height. Those derived from the vehicle exhaust decrease with the height increase. The diurnal and height variations of sources reflect the emission and transport characteristics of atmospheric CO2 in Jiading district of Shanghai.

Improving the environment in urban areas

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adamkus, V.V.

1994-12-31

The author discusses the need for improvements to the environment in urban areas, and efforts being made under the direction of the Environmental Protection Agency (EPA) to address these problems. The impact the new Clean Air Act can have on emissions from gasoline powered autos, diesel burning trucks, fixed emission sources ranging from utilities to chemical plants, and consumer products like hair sprays and charcoal starters, will all work together to improve air quality in urban areas. The author also discusses Brownfields Economic Redevelopment Plan efforts being supported by the EPA in a coordinated plan to get municipalities involved inmore » cleaning up areas with pollution, to remove the blight on the urban areas, provide new land for development, and promote additional jobs.« less

Impact on air quality of measures to reduce CO2 emissions from road traffic in Basel, Rotterdam, Xi'an and Suzhou

NASA Astrophysics Data System (ADS)

Keuken, M. P.; Jonkers, S.; Verhagen, H. L. M.; Perez, L.; Trüeb, S.; Okkerse, W.-J.; Liu, J.; Pan, X. C.; Zheng, L.; Wang, H.; Xu, R.; Sabel, C. E.

2014-12-01

Two traffic scenarios to reduce CO2 emissions from road traffic in two European cities (Basel and Rotterdam) and two Chinese cities (Xi'an and Suzhou) were evaluated in terms of their impact on air quality. The two scenarios, one modelling a reduction of private vehicle kilometres driven by 10% on urban streets and the other modelling the introduction of 50% electric-powered private vehicle kilometres on urban streets, were both compared to a scenario following “business-as-usual”: 2020-BAU. The annual average concentrations of NO2, PM2.5, PM10 and elemental carbon (EC) were modelled separately in busy street canyons, near urban motorways and in the remainder of the urban area. It was concluded that traffic-related CO2 emissions in 2020-BAU could be expected to remain at the levels of 2010 in Basel and Rotterdam, while in Xi'an and Suzhou to increase 30-50% due to growth in the traffic volume. Traffic-related CO2 emissions may be reduced by up to 5% and 25%, respectively using the first and second scenarios. Air pollution in the Chinese cities is a factor 3 to 5 higher than in the European cities in 2010 and 2020-BAU. The impact of both CO2 reduction scenarios on air quality in 2020-BAU is limited. In Europe, due to implementation of stringent emission standards in all sectors, air quality is expected to improve at both the urban background and near busy road traffic. In China, the regional background is expected to improve for EC, stabilize for PM2.5 and PM10, and decrease for NO2. The urban background follows this regional trend, while near busy road traffic, air pollution will remain elevated due to the considerable growth in traffic volume. A major constraint for modelling air quality in China is access to the input data required and lack of measurements at ground level for validation.

Vehicle NOx emission plume isotopic signatures: Spatial variability across the eastern United States

NASA Astrophysics Data System (ADS)

Miller, David J.; Wojtal, Paul K.; Clark, Sydney C.; Hastings, Meredith G.

2017-04-01

On-road vehicle nitrogen oxide (NOx) sources currently dominate the U.S. anthropogenic emission budgets, yet vehicle NOx emissions have uncertain contributions to oxidized nitrogen (N) deposition patterns. Isotopic signatures serve as a potentially valuable observational tool to trace source contributions to NOx chemistry and N deposition, yet in situ emission signatures are underconstrained. We characterize the spatiotemporal variability of vehicle NOx emission isotopic signatures (δ15N-NOx) representative of U.S. vehicle fleet-integrated emission plumes. A novel combination of on-road mobile and stationary urban measurements is performed using a field and laboratory-verified technique for actively capturing NOx in solution to quantify δ15N-NOx at hourly resolution. On-road δ15N-NOx upwind of Providence, RI, ranged from -7 to -3‰. Simultaneous urban background δ15N-NOx observations showed comparable range and variations with on-road measurements, suggesting that vehicles dominate NOx emissions in the Providence area. On-road spatial δ15N-NOx variations of -9 to -2‰ were observed under various driving conditions in six urban metropolitan areas and rural interstate highways during summer and autumn in the U.S. Northeast and Midwest. Although isotopic signatures were insensitive to on-road driving mode variations, statistically significant correlations were found between δ15N-NOx and NOx emission factor extremes associated with heavy diesel emitter contributions. Overall, these results constrain an isotopic signature of fleet-integrated roadway NOx emission plumes, which have important implications for distinguishing vehicle NOx from other sources and tracking emission contributions to NOx chemistry and N deposition.

Source apportionment of PM2.5 at urban and suburban areas of the Pearl River Delta region, south China - With emphasis on ship emissions.

PubMed

Tao, Jun; Zhang, Leiming; Cao, Junji; Zhong, Liuju; Chen, Dongsheng; Yang, Yihong; Chen, Duohong; Chen, Laiguo; Zhang, Zhisheng; Wu, Yunfei; Xia, Yunjie; Ye, Siqi; Zhang, Renjian

2017-01-01

Daily PM 2.5 samples were collected at an urban site in Guangzhou in 2014 and at a suburban site in Zhuhai in 2014-2015. Samples were subject to chemical analysis for various chemical components including organic carbon (OC), element carbon (EC), major water-soluble inorganic ions, and trace elements. The annual average PM 2.5 mass concentration was 48±22μgm -3 and 45±25μgm -3 in Guangzhou and Zhuhai, respectively, with the highest seasonal average concentration in winter and the lowest in summer at both sites. Regional transport of pollutants accompanied with different air mass origins arriving at the two sites and pollution sources in between the two cities caused larger seasonal variations in Zhuhai (>a factor of 3.5) than in Guangzhou (17% of PM 2.5 mass concentrations. Copyright © 2016 Elsevier B.V. All rights reserved.

U.S. EPA'S RESEARCH TO UPDATE GUIDANCE FOR QUANTIFYING LANDFILL GAS EMISSIONS

EPA Science Inventory

Landfill emissions, if left uncontrolled, contribute to air toxics, climate change, tropospheric ozone, and urban smog. EPA's Office of Research and Development is conducting research to help update EPA's landfill gas emission factors. The last update to EPA's landfill gas emiss...

Urbanization-induced population migration has reduced ambient PM2.5 concentrations in China

PubMed Central

Shen, Huizhong; Tao, Shu; Chen, Yilin; Ciais, Philippe; Güneralp, Burak; Ru, Muye; Zhong, Qirui; Yun, Xiao; Zhu, Xi; Huang, Tianbo; Tao, Wei; Chen, Yuanchen; Li, Bengang; Wang, Xilong; Liu, Wenxin; Liu, Junfeng; Zhao, Shuqing

2017-01-01

Direct residential and transportation energy consumption (RTC) contributes significantly to ambient fine particulate matter with a diameter smaller than 2.5 μm (PM2.5) in China. During massive rural-urban migration, population and pollutant emissions from RTC have evolved in terms of magnitude and geographic distribution, which was thought to worsen PM2.5 levels in cities but has not been quantitatively addressed. We quantify the temporal trends and spatial patterns of migration to cities and evaluate their associated pollutant emissions from RTC and subsequent health impact from 1980 to 2030. We show that, despite increased urban RTC emissions due to migration, the net effect of migration in China has been a reduction of PM2.5 exposure, primarily because of an unequal distribution of RTC energy mixes between urban and rural areas. After migration, people have switched to cleaner fuel types, which considerably lessened regional emissions. Consequently, the national average PM2.5 exposure concentration in 2010 was reduced by 3.9 μg/m3 (90% confidence interval, 3.0 to 5.4 μg/m3) due to migration, corresponding to an annual reduction of 36,000 (19,000 to 47,000) premature deaths. This reduction was the result of an increase in deaths by 142,000 (78,000 to 181,000) due to migrants swarming into cities and decreases in deaths by 148,000 (76,000 to 194,000) and 29,000 (15,000 to 39,000) due to transitions to a cleaner energy mix and lower urban population densities, respectively. Locally, however, megacities such as Beijing and Shanghai experienced increases in PM2.5 exposure associated with migration because these cities received massive immigration, which has driven a large increase in local emissions. PMID:28776030

Siting Background Towers to Characterize Incoming Air for Urban Greenhouse Gas Estimation: A Case Study in the Washington, DC/Baltimore Area

NASA Astrophysics Data System (ADS)

Mueller, K.; Yadav, V.; Lopez-Coto, I.; Karion, A.; Gourdji, S.; Martin, C.; Whetstone, J.

2018-03-01

There is increased interest in understanding urban greenhouse gas (GHG) emissions. To accurately estimate city emissions, the influence of extraurban fluxes must first be removed from urban greenhouse gas (GHG) observations. This is especially true for regions, such as the U.S. Northeastern Corridor-Baltimore/Washington, DC (NEC-B/W), downwind of large fluxes. To help site background towers for the NEC-B/W, we use a coupled Bayesian Information Criteria and geostatistical regression approach to help site four background locations that best explain CO2 variability due to extraurban fluxes modeled at 12 urban towers. The synthetic experiment uses an atmospheric transport and dispersion model coupled with two different flux inventories to create modeled observations and evaluate 15 candidate towers located along the urban domain for February and July 2013. The analysis shows that the average ratios of extraurban inflow to total modeled enhancements at urban towers are 21% to 36% in February and 31% to 43% in July. In July, the incoming air dominates the total variability of synthetic enhancements at the urban towers (R2 = 0.58). Modeled observations from the selected background towers generally capture the variability in the synthetic CO2 enhancements at urban towers (R2 = 0.75, root-mean-square error (RMSE) = 3.64 ppm; R2 = 0.43, RMSE = 4.96 ppm for February and July). However, errors associated with representing background air can be up to 10 ppm for any given observation even with an optimal background tower configuration. More sophisticated methods may be necessary to represent background air to accurately estimate urban GHG emissions.

Global time trends in PAH emissions from motor vehicles

NASA Astrophysics Data System (ADS)

Shen, Huizhong; Tao, Shu; Wang, Rong; Wang, Bin; Shen, Guofeng; Li, Wei; Su, Shenshen; Huang, Ye; Wang, Xilong; Liu, Wenxin; Li, Bengang; Sun, Kang

2011-04-01

Emission from motor vehicles is the most important source of polycyclic aromatic hydrocarbons (PAHs) in urban areas. Emission factors of individual PAHs for motor vehicles reported in the literature varied 4 to 5 orders of magnitude, leading to high uncertainty in emission inventory. In this study, key factors affecting emission factors of PAHs (EF PAH) for motor vehicles were evaluated quantitatively based on thousands of EF PAH measured in 16 countries for over 50 years. The result was used to develop a global emission inventory of PAHs from motor vehicles. It was found that country and vehicle model year are the most important factors affecting EF PAH, which can be quantified using a monovariate regression model with per capita gross domestic production (purchasing power parity) as a sole independent variable. On average, 29% of variation in log-transformed EF PAH could be explained by the model, which was equivalent to 90% reduction in overall uncertainty on arithmetic scale. The model was used to predict EF PAH and subsequently PAH emissions from motor vehicles for various countries in the world during a period from 1971 to 2030. It was estimated that the global emission reached its peak value of approximate 101 Gg in 1978 and decreased afterwards due to emission control in developed countries. The annual emission picked up again since 1990 owing to accelerated energy consumption in China and other developing countries. With more and more rigid control measures taken in the developing world, global emission of PAHs is currently passing its second peak. It was predicted that the emission would decrease from 77 Gg in 2010 to 42 Gg in 2030.

Projection of anthropogenic volatile organic compounds (VOCs) emissions in China for the period 2010-2020

NASA Astrophysics Data System (ADS)

Wei, Wei; Wang, Shuxiao; Hao, Jiming; Cheng, Shuiyuan

2011-12-01

The future (2010-2020) anthropogenic volatile organic compounds (VOCs) emissions in China were projected in this study using 2005 as the reference year. The projections are based on the assumptions of a lower population growth rate (less than 1%), continuous economic development with high GDP growth, and increased urbanization. The results show that the national VOCs emissions would continuously increase from 19.4 Tg in 2005 to 25.9 Tg in 2020, even if China's legislative standards for VOCs emissions are implemented effectively in the future (assumed as control scenario I). The contributions of various emission sources were found to differ greatly in the period of 2010-2020. Solvent utilization would become the largest contributor rising from 22% to 37%, along with an increase for industrial processes from 17% to 24%. However, road vehicle emissions would rapidly decrease from 25% to 11% due to the strict VOCs emission limit standards in China, along with the decrease for stationary fuel combustion from 23% to 16% caused by the reduction of domestic biofuel consumption. Additionally, there would be a notable divergence among provincial emissions. The developed eastern and coastal regions would emit more VOCs than the relatively underdeveloped western and inland regions. Moreover, this divergence grows in the future. When we assumed stricter control measures for solvent utilization and industrial processes (control scenario II) for that period, the projections revealed national VOCs emissions per year would remain at about 20 Tg, if exhaust after-treatment systems are installed in newly-built factories (after 2005) for the most important industrial sources, and the market shares of "low/zero-VOCs" products in paints, adhesives and printing ink raise to the present levels of developed countries. The emission abatements of the two types of measures were estimated to be similar. While scenario II indicates that the sectoral and provincial differences of VOCs emissions would still exist, they would be smaller than in scenario I.

Climate change and developing-country cities: implications for environmental health and equity.

PubMed

Campbell-Lendrum, Diarmid; Corvalán, Carlos

2007-05-01

Climate change is an emerging threat to global public health. It is also highly inequitable, as the greatest risks are to the poorest populations, who have contributed least to greenhouse gas (GHG) emissions. The rapid economic development and the concurrent urbanization of poorer countries mean that developing-country cities will be both vulnerable to health hazards from climate change and, simultaneously, an increasing contributor to the problem. We review the specific health vulnerabilities of urban populations in developing countries and highlight the range of large direct health effects of energy policies that are concentrated in urban areas. Common vulnerability factors include coastal location, exposure to the urban heat-island effect, high levels of outdoor and indoor air pollution, high population density, and poor sanitation. There are clear opportunities for simultaneously improving health and cutting GHG emissions most obviously through policies related to transport systems, urban planning, building regulations and household energy supply. These influence some of the largest current global health burdens, including approximately 800,000 annual deaths from ambient urban air pollution, 1.2 million from road-traffic accidents, 1.9 million from physical inactivity, and 1.5 million per year from indoor air pollution. GHG emissions and health protection in developing-country cities are likely to become increasingly prominent in policy development. There is a need for a more active input from the health sector to ensure that development and health policies contribute to a preventive approach to local and global environmental sustainability, urban population health, and health equity.

Quantifying nonpoint source emissions and their water quality responses in a complex catchment: A case study of a typical urban-rural mixed catchment

NASA Astrophysics Data System (ADS)

Chen, Lei; Dai, Ying; Zhi, Xiaosha; Xie, Hui; Shen, Zhenyao

2018-04-01

As two key threats to receiving water bodies, the generation mechanisms and processes of urban and agricultural nonpoint sources (NPSs) show clear differences, which lead to distinct characteristics of water quality responses with mixed land-uses catchments compared to single land-use ones. However, few studies have provided such insights in these characteristic or quantified different water environment responses to NPS pollution. In this study, an integrated modelling approach was developed for those complex catchments by combining three commonly used models: SWMM (Storm Water Management Model), SWAT (Soil and Water Assessment Tool) and MIKE 11. A case study was performed in a typical urban-rural catchment of Chao Lake, China. The simulated results indicated that urban NPS pollution responded sensitively to rainfall events and was greatly affected by the antecedent dry days. Compare to urban NPS, agricultural NPS pollution was characterized with the time-lag to rainfall depended on soil moisture and the post-rain-season emissions carried by lateral flows, and were also affected by the local farm-practice schedule. With comprehensive impacts from urban-rural land-uses, the time-interleaved urban and agricultural NPS pollution emissions and more abundant pollution accumulation both led to a decrease in the responsive time and an increase in the frequency of peak pollution concentration values even during the dry season. These obtained characteristics can provide guidance for drafting watershed management plans in similar mixed land use catchments.

Effects of canyon geometry on the distribution of traffic-related air pollution in a large urban area: Implications of a multi-canyon air pollution dispersion model

NASA Astrophysics Data System (ADS)

Fu, Xiangwen; Liu, Junfeng; Ban-Weiss, George A.; Zhang, Jiachen; Huang, Xin; Ouyang, Bin; Popoola, Olalekan; Tao, Shu

2017-09-01

Street canyons are ubiquitous in urban areas. Traffic-related air pollutants in street canyons can adversely affect human health. In this study, an urban-scale traffic pollution dispersion model is developed considering street distribution, canyon geometry, background meteorology, traffic assignment, traffic emissions and air pollutant dispersion. In the model, vehicle exhausts generated from traffic flows first disperse inside street canyons along the micro-scale wind field generated by computational fluid dynamics (CFD) model. Then, pollutants leave the street canyon and further disperse over the urban area. On the basis of this model, the effects of canyon geometry on the distribution of NOx and CO from traffic emissions were studied over the center of Beijing. We found that an increase in building height leads to heavier pollution inside canyons and lower pollution outside canyons at pedestrian level, resulting in higher domain-averaged concentrations over the area. In addition, canyons with highly even or highly uneven building heights on each side of the street tend to lower the urban-scale air pollution concentrations at pedestrian level. Further, increasing street widths tends to lead to lower pollutant concentrations by reducing emissions and enhancing ventilation simultaneously. Our results indicate that canyon geometry strongly influences human exposure to traffic pollutants in the populated urban area. Carefully planning street layout and canyon geometry while considering traffic demand as well as local weather patterns may significantly reduce inhalation of unhealthy air by urban residents.

A Numerical Simulation of Traffic-Related Air Pollution Exposures in Urban Street Canyons

NASA Astrophysics Data System (ADS)

Liu, J.; Fu, X.; Tao, S.

2016-12-01

Urban street canyons are usually associated with intensive vehicle emissions. However, the high buildings successively along both sides of a street block the dispersion of traffic-generated air pollutants, which enhances human exposure and adversely affects human health. In this study, an urban scale traffic pollution dispersion model is developed with the consideration of street distribution, canyon geometry, background meteorology, traffic assignment, traffic emissions and air pollutant dispersion. Vehicle exhausts generated from traffic flows will first disperse inside a street canyon along the micro-scale wind field (generated by computational fluid dynamics (CFD) model) and then leave the street canyon and further disperse over the urban area. On the basis of this model, the effects of canyon geometry on the distribution of NOx and CO from traffic emissions were studied over the center of Beijing, China. We found that an increase of building height along the streets leads to higher pollution levels inside streets and lower pollution levels outside, resulting in higher domain-averaged concentrations over the area. In addition, street canyons with equal (or highly uneven) building heights on two sides of a street tend to lower the urban-scale air pollution concentrations at pedestrian level. Our results indicate that canyon geometry strongly influences human exposure to traffic pollutants in the populated urban area. Carefully planning street layout and canyon geometry in consideration of traffic demand as well as local weather pattern may significantly reduce the chances of unhealthy air being inhaled by urban residents.

The impact of traffic emissions on air quality in the Berlin-Brandenburg region - a case study on cycling scenarios

NASA Astrophysics Data System (ADS)

Kuik, F.; Lauer, A.; von Schneidemesser, E.; Butler, T. M.

2016-12-01

Many European cities continue to struggle with exceedances of NO2 limit values at measurement sites near roads, of which a large contribution is attributed to emissions from traffic. In this study, we explore how urban air quality can be improved with different traffic measures using the example of the Berlin-Brandenburg region. In order to simulate urban background air quality we use the Weather Research and Forecasting model with chemistry (WRF-Chem) at a horizontal resolution of 1km. We use emission input data at a horizontal resolution of 1km obtained by downscaling TNO-MACC III emissions based on local proxy data including population and traffic densities. In addition we use a statistical approach combining the simulated urban background concentrations with information on traffic densities to estimate NO2 at street level. This helps assessing whether the emission scenarios studied here can lead to significant reductions in NO2 concentrations at street level. The emission scenarios in this study represent a range of scenarios in which car traffic is replaced with bicycle traffic. Part of this study was an initial discussion phase with stakeholders, including policy makers and NGOs. The discussions have shown that the different stakeholders are interested in a scientific assessment of the impact of replacing car traffic with bicycle traffic in the Berlin-Brandenburg urban area. Local policy makers responsible for city planning and implementing traffic measures can make best use of scientific modeling results if input data and scenarios are as realistic as possible. For these reasons, the scenarios cover very idealized optimistic ("all passenger cars are replaced by bicycles") and pessimistic ("all cyclists are replaced by cars") scenarios to explore the sensitivity of simulated urban background air quality to these changes, as well as additional scenarios based on city-specific data to analyze more realistic situations. Of particular interest is how these impact street level NO2 concentrations.

Urban impact on air quality in RegCM/CAMx couple for MEGAPOLI project - high resolution sensitivity study

NASA Astrophysics Data System (ADS)

Halenka, T.; Huszar, P.; Belda, M.

2010-09-01

Recent studies show considerable effect of atmospheric chemistry and aerosols on climate on regional and local scale. For the purpose of qualifying and quantifying the magnitude of climate forcing due to atmospheric chemistry/aerosols on regional scale, the development of coupling of regional climate model and chemistry/aerosol model was started on the Department of Meteorology and Environmental Protection, Charles University, Prague, for the EC FP6 Project QUANTIFY and EC FP6 Project CECILIA. For this coupling, existing regional climate model and chemistry transport model have been used at very high resolution of 10km grid. Climate is calculated using RegCM while chemistry is solved by CAMx. The experiments with the couple have been prepared for EC FP7 project MEGAPOLI assessing the impact of the megacities and industrialized areas on climate. Meteorological fields generated by RCM drive CAMx transport, chemistry and a dry/wet deposition. A preprocessor utility was developed for transforming RegCM provided fields to CAMx input fields and format. New domain have been settled for MEGAPOLI purpose in 10km resolution including all the European "megacities" regions, i.e. London metropolitan area, Paris region, industrialized Ruhr area, Po valley etc. There is critical issue of the emission inventories available for 10km resolution including the urban hot-spots, TNO emissions are adopted for this sensitivity study in 10km resolution for comparison of the results with the simulation based on merged TNO emissions, i.e. basically original EMEP emissions at 50 km grid. The sensitivity test to switch on/off Paris area emissions is analysed as well. Preliminary results for year 2005 are presented and discussed to reveal whether the concept of effective emission indices could help to parameterize the urban plume effects in lower resolution models. Interactive coupling is compared to study the potential of possible impact of urban air-pollution to the urban area climate.

Natural gas consumption, income, urbanization, and CO2 emissions in China and India.

PubMed

Solarin, Sakiru Adebola; Lean, Hooi Hooi

2016-09-01

The objective of this study is to examine the impact of natural gas consumption, output, and urbanization on CO2 emission in China and India for the period, 1965-2013. A cointegraton test, which provides for endogenously determined structural breaks, has been applied to examine the long-run relationship and to investigate the presence of environmental Kuznets curve (EKC) in the two countries. The presence of causal relationship between the variables is also investigated. The findings show that there is a long-run relationship in the variables and natural gas, real GDP, and urbanization have long-run positive impact on emission in both countries. There is no evidence for EKC in China and India. The findings further suggest that there is a long-run feedback relationship between the variables. The policy inferences of these findings are discussed.

Assessing the air quality impact of nitrogen oxides and benzene from road traffic and domestic heating and the associated cancer risk in an urban area of Verona (Italy)

NASA Astrophysics Data System (ADS)

Schiavon, Marco; Redivo, Martina; Antonacci, Gianluca; Rada, Elena Cristina; Ragazzi, Marco; Zardi, Dino; Giovannini, Lorenzo

2015-11-01

Simulations of emission and dispersion of nitrogen oxides (NOx) are performed in an urban area of Verona (Italy), characterized by street canyons and typical sources of urban pollutants. Two dominant source categories are considered: road traffic and, as an element of novelty, domestic heaters. Also, to assess the impact of urban air pollution on human health and, in particular, the cancer risk, simulations of emission and dispersion of benzene are carried out. Emissions from road traffic are estimated by the COPERT 4 algorithm, whilst NOx emission factors from domestic heaters are retrieved by means of criteria provided in the technical literature. Then maps of the annual mean concentrations of NOx and benzene are calculated using the AUSTAL2000 dispersion model, considering both scenarios representing the current situation, and scenarios simulating the introduction of environmental strategies for air pollution mitigation. The simulations highlight potentially critical situations of human exposure that may not be detected by the conventional network of air quality monitoring stations. The proposed methodology provides a support for air quality policies, such as planning targeted measurement campaigns, re-locating monitoring stations and adopting measures in favour of better air quality in urban planning. In particular, the estimation of the induced cancer risk is an important starting point to conduct zoning analyses and to detect the areas where population is more directly exposed to potential risks for health.

The relationship between airborne small ions and particles in urban environments

NASA Astrophysics Data System (ADS)

Ling, Xuan; Jayaratne, Rohan; Morawska, Lidia

2013-11-01

Ions play an important role in affecting climate and particle formation in the atmosphere. Small ions rapidly attach to particles in the air and, therefore, studies have shown that they are suppressed in polluted environments. Urban environments, in particular, are dominated by motor vehicle emissions and, since motor vehicles are a source of both particles and small ions, the relationship between these two parameters is not well known. In order to gain a better understanding of this relationship, an intensive campaign was undertaken where particles and small ions of both signs were monitored over two week periods at each of three sites A, B and C that were affected to varying degrees by vehicle emissions. Site A was close to a major road and reported the highest particle number and lowest small ion concentrations. Precursors from motor vehicle emissions gave rise to clear particle formation events on five days and, on each day this was accompanied by a suppression of small ions. Observations at Site B, which was located within the urban airshed, though not adjacent to motor traffic, showed particle enhancement but no formation events. Site C was a clean site, away from urban sources. This site reported the lowest particle number and highest small ion concentration. The positive small ion concentration was 10%-40% higher than the corresponding negative value at all sites. These results confirm previous findings that there is a clear inverse relationship between small ions and particles in urban environments dominated by motor vehicle emissions.

Urbanization and the Carbon Cycle: Synthesis of Ongoing Research

NASA Astrophysics Data System (ADS)

Gurney, K. R.; Duren, R. M.; Hutyra, L.; Ehleringer, J. R.; Patarasuk, R.; Song, Y.; Huang, J.; Davis, K.; Kort, E. A.; Shepson, P. B.; Turnbull, J. C.; Lauvaux, T.; Rao, P.; Eldering, A.; Miller, C. E.; Wofsy, S.; McKain, K.; Mendoza, D. L.; Lin, J. C.; Sweeney, C.; Miles, N. L.; Richardson, S.; Cambaliza, M. O. L.

2015-12-01

Given the explosive growth in urbanization and its dominant role in current and future global greenhouse gas emissions, urban areas have received increasing research attention from the carbon cycle science community. The emerging focus is driven by the increasingly dense atmospheric observing capabilities - ground and space-based - in addition to the rising profile of cities within international climate change policymaking. Dominated by anthropogenic emissions, urban carbon cycle research requires a cross-disciplinary perspective with contributions from disciplines such as engineering, economics, social theory, and atmospheric science. We review the recent results from a sample of the active urban carbon research efforts including the INFLUX experiment (Indianapolis), the Megacity carbon project (Los Angeles), Salt Lake City, and Boston. Each of these efforts represent unique approaches in pursuit of different scientific and policy questions and assist in setting priorities for future research. From top-down atmospheric measurement systems to bottom-up estimation, these research efforts offer a view of the challenges and opportunities in urban carbon cycle research.

High-resolution atmospheric inversion of urban CO2 emissions during the dormant season of the Indianapolis Flux Experiment (INFLUX)

NASA Astrophysics Data System (ADS)

Lauvaux, Thomas; Miles, Natasha L.; Deng, Aijun; Richardson, Scott J.; Cambaliza, Maria O.; Davis, Kenneth J.; Gaudet, Brian; Gurney, Kevin R.; Huang, Jianhua; O'Keefe, Darragh; Song, Yang; Karion, Anna; Oda, Tomohiro; Patarasuk, Risa; Razlivanov, Igor; Sarmiento, Daniel; Shepson, Paul; Sweeney, Colm; Turnbull, Jocelyn; Wu, Kai

2016-05-01

Based on a uniquely dense network of surface towers measuring continuously the atmospheric concentrations of greenhouse gases (GHGs), we developed the first comprehensive monitoring systems of CO2 emissions at high resolution over the city of Indianapolis. The urban inversion evaluated over the 2012-2013 dormant season showed a statistically significant increase of about 20% (from 4.5 to 5.7 MtC ± 0.23 MtC) compared to the Hestia CO2 emission estimate, a state-of-the-art building-level emission product. Spatial structures in prior emission errors, mostly undetermined, appeared to affect the spatial pattern in the inverse solution and the total carbon budget over the entire area by up to 15%, while the inverse solution remains fairly insensitive to the CO2 boundary inflow and to the different prior emissions (i.e., ODIAC). Preceding the surface emission optimization, we improved the atmospheric simulations using a meteorological data assimilation system also informing our Bayesian inversion system through updated observations error variances. Finally, we estimated the uncertainties associated with undetermined parameters using an ensemble of inversions. The total CO2 emissions based on the ensemble mean and quartiles (5.26-5.91 MtC) were statistically different compared to the prior total emissions (4.1 to 4.5 MtC). Considering the relatively small sensitivity to the different parameters, we conclude that atmospheric inversions are potentially able to constrain the carbon budget of the city, assuming sufficient data to measure the inflow of GHG over the city, but additional information on prior emission error structures are required to determine the spatial structures of urban emissions at high resolution.

Urbanisation and greening of Indian cities: Problems, practices, and policies.

PubMed

Imam, Aabshar U K; Banerjee, Uttam Kumar

2016-05-01

Progress of the Indian economy is threatened by the impact of climate change. Generation of urban heat islands (UHIs), waning of urban green cover, increase in carbon emissions and air pollution deteriorate the living environment. Rise in urban temperatures and heat stress induced mortality remain major concerns. Although the National Action Plan on Climate Change emphasises the national missions of 'enhanced energy efficiency', and 'green India', little research has been devoted to explore the passive cooling potential of urban greenery in India, thus lending uniqueness to this study. The manifestations of unplanned urban development (UHIs, escalated carbon emissions, air pollution) are discussed and corroborated with identification of contributory factors. Contemporary greening practices and bye-laws in four major Indian cities (New Delhi, Pune, Chennai, and Visakhapatnam) are analysed and compared with global best practices. The findings are used to propose planning guidelines which are expected to assist in consolidating natural sustainability of emerging economies.

A Comparative Study on Ozone Photochemical Formation in the Megacities of Tianjin and Shanghai, China

NASA Astrophysics Data System (ADS)

Ran, L.; Zhao, C.; Xu, W.; Geng, F.; Lu, X.; Han, M.; Lin, W.; Xu, X.

2011-12-01

As one of the most widespread and stubborn environmental issues, the ozone problem has been of particular concern for many years, given the potential adverse effects of high ozone concentrations on public health and agricultural productivity. In the past decades, rapid urbanization and industrialization have given rise to a significant increase in ozone precursor emissions in many regions of China, especially in the densely populated megacities. Due to the highly nonlinear impacts of ozone precursors including nitrogen oxides (NOx) and various volatile organic compounds (VOCs) on ozone photochemistry, formation of ozone affected by different precursor emission patterns in those megacities has exhibited different characteristics. A comparative analysis of ozone photochemical production in the megacities of Tianjin and Shanghai has thus been carried out, using the data sets of surface ozone and its precursors measured respectively at an urban and a suburban site of the two megacities during the summertime. Observation-based analysis indicated an elevated ozone daily peak under photochemistry dominant conditions from the urban center to the suburb in both regions, nevertheless bearing different reasons. Ozone production was generally sensitive to VOCs in the Tianjin region, leading to a relatively higher level of ozone in the suburb where reactive VOCs were abundantly released from a number of industrial facilities, whereas a sensitivity of ozone production to NOx was found in Shanghai. The high level of NOx emitted mainly by motor vehicles in urban Shanghai largely inhibited ozone formation and resulted in a much more rapid decrease in ozone concentrations after reaching the daily maximum around midday compared with the other three areas. Ozone pollution in the megacity of Tianjin was more representative of the regional condition, implying that combined efforts would be needed to bring the ozone problem under control within this region. Improved understanding of ozone formation in the two megacities would be quite imperative and critical to provide a solid scientific basis for designing effective ozone control strategies.

Photo-chemical transport modelling of tropospheric ozone: A review

NASA Astrophysics Data System (ADS)

Sharma, Sumit; Sharma, Prateek; Khare, Mukesh

2017-06-01

Ground level ozone (GLO), a secondary pollutant having adverse impact on human health, ecology, and agricultural productivity, apart from being a major contributor to global warming, has been a subject matter of several studies. In order to identify appropriate strategies to control GLO levels, accurate assessment and prediction is essential, for which elaborate simulation and modelling is required. Several studies have been undertaken in the past to simulate GLO levels at different scales and for various applications. It is important to evaluate these studies, widely spread over in literature. This paper aims to critically review various studies that have been undertaken, especially in the past 15 years (2000-15) to model GLO. The review has been done of the studies that range over different spatial scales - urban to regional and continental to global. It also includes a review of performance evaluation and sensitivity analysis of photo-chemical transport models in order to assess the extent of application of these models and their predictive capability. The review indicates following major findings: (a) models tend to over-estimate the night-time GLO concentrations due to limited titration of GLO with NO within the model; (b) dominance of contribution from far-off regional sources to average ozone concentration in the urban region and higher contribution of local sources during days of high ozone episodes; requiring strategies for controlling precursor emissions at both regional and local scales; (c) greater influence of NOx over VOC in export of ozone from urban regions due to shifting of urban plumes from VOC-sensitive regime to NOx-sensitive as they move out from city centres to neighbouring rural regions; (d) models with finer resolution inputs perform better to a certain extent, however, further improvement in resolutions (beyond 10 km) did not show improvement always; (e) future projections show an increase in GLO concentrations mainly due to rise in temperatures and biogenic VOC emissions.

Water Soluble Organic Nitrogen (WSON) in Ambient Fine Particles Over a Megacity in South China: Spatiotemporal Variations and Source Apportionment

NASA Astrophysics Data System (ADS)

Yu, Xu; Yu, Qingqing; Zhu, Ming; Tang, Mingjin; Li, Sheng; Yang, Weiqiang; Zhang, Yanli; Deng, Wei; Li, Guanghui; Yu, Yuegang; Huang, Zhonghui; Song, Wei; Ding, Xiang; Hu, Qihou; Li, Jun; Bi, Xinhui; Wang, Xinming

2017-12-01

Organic nitrogen aerosols are complex mixtures and important compositions in ambient fine particulate matters (PM2.5), yet their sources and spatiotemporal patterns are not well understood particularly in regions influenced by intensive human activities. In this study, filter-based ambient PM2.5 samples at four stations (one urban, two rural, plus one urban roadside) and PM samples from combustion sources (vehicle exhaust, ship emission, and biomass burning) were collected in the coastal megacity Guangzhou, south China, for determining water soluble organic nitrogen (WSON) along with other organic and inorganic species. The annual average WSON concentrations, as well as the ratios of WSON to water soluble total nitrogen, were all significantly higher at rural sites than urban sites. Average WSON concentrations at the four sites during the wet season were quite near each other, ranging from 0.41 to 0.49 μg/m3; however, they became 2 times higher at the rural sites than at the urban sites during the dry season. Five major sources for WSON were identified through positive matrix factorization analysis. Vehicle emission (29.3%), biomass burning (22.8%), and secondary formation (20.2%) were three dominant sources of WSON at the urban station, while vehicle emission (45.4%) and dust (28.6%) were two dominant sources at the urban roadside station. At the two rural sites biomass burning (51.1% and 34.1%, respectively) and secondary formation (17.8% and 30.5%, respectively) were dominant sources of WSON. Ship emission contributed 8-12% of WSON at the four sites. Natural vegetation seemed to have very minor contribution to WSON.

Nonzero-Sum Relationships in Mitigating Urban Carbon Emissions: A Dynamic Network Simulation.

PubMed

Chen, Shaoqing; Chen, Bin; Su, Meirong

2015-10-06

The "stove-pipe" way of thinking has been mostly used in mitigating carbon emissions and managing socioeconomics because of its convenience of implementation. However, systems-oriented approaches become imperative in pursuit of an efficient regulation of carbon emissions from systems as complicated as urban systems. The aim of this paper is to establish a dynamic network approach that is capable of assessing the effectiveness of carbon emissions mitigation in a more holistic way. A carbon metabolic network is constructed by modeling the carbon flows between economic sectors and environment. With the network shocked by interventions to the sectoral carbon flows, indirect emissions from the city are accounted for under certain carbon mitigation strategies. The nonzero-sum relationships between sectors and environmental components are identified based on utility analysis, which synthesize the nature of direct and indirect network interactions. The results of the case study of Beijing suggest that the stove-pipe mitigation strategies targeted the economic sectors might be not as efficient as they were expected. A direct cutting in material or energy import to the sectors may result in a rebound in indirect emissions and thus fails to achieve the carbon mitigation goal of the city as a whole. A promising way of foreseeing the dynamic mechanism of emissions is to analyze the nonzero-sum relationships between important urban components. Thinking cities as systems of interactions, the network approach is potentially a strong tool for appraising and filtering mitigation strategies of carbon emissions.

Occupational exposure to roadway emissions and inside informal settlements in sub-Saharan Africa: A pilot study in Nairobi, Kenya

PubMed Central

Ngo, Nicole S.; Gatari, Michael; Yan, Beizhan; Chillrud, Steven N.; Bouhamam, Kheira; Kinneym, Patrick L.

2015-01-01

Few studies examine urban air pollution in sub-Saharan Africa (SSA), yet urbanization rates there are among the highest in the world. In this study, we measured 8-hr average occupational exposure levels of fine particulate matter (PM2.5), black carbon (BC), ultra violet active-particulate matter (UV-PM), and trace elements for individuals who worked along roadways in Nairobi, specifically bus drivers, garage workers, street vendors, and women who worked inside informal settlements. We found BC and re-suspended dust were important contributors to PM2.5 levels for all study populations, particularly among bus drivers, while PM2.5 exposure levels for garage workers, street vendors, and informal settlement residents were not statistically different from each other. We also found a strong signal for biomass emissions and trash burning, which is common in Nairobi’s low-income areas and open-air garages. These results suggest that the large portion of urban residents in SSA who walk along roadways would benefit from air quality regulations targeting roadway emissions from diesel vehicles, dust, and trash burning. This is the first study to measure occupational exposure to urban air pollution in SSA and results imply that roadway emissions are a serious public health concern. PMID:26034383

Occupational exposure to roadway emissions and inside informal settlements in sub-Saharan Africa: A pilot study in Nairobi, Kenya

NASA Astrophysics Data System (ADS)

Ngo, Nicole S.; Gatari, Michael; Yan, Beizhan; Chillrud, Steven N.; Bouhamam, Kheira; Kinney, Patrick L.

2015-06-01

Few studies examine urban air pollution in sub-Saharan Africa (SSA), yet urbanization rates there are among the highest in the world. In this study, we measured 8-hr average occupational exposure levels of fine particulate matter (PM2.5), black carbon (BC), ultra violet active-particulate matter (UV-PM), and trace elements for individuals who worked along roadways in Nairobi, specifically bus drivers, garage workers, street vendors, and women who worked inside informal settlements. We found BC and re-suspended dust were important contributors to PM2.5 levels for all study populations, particularly among bus drivers, while PM2.5 exposure levels for garage workers, street vendors, and informal settlement residents were not statistically different from each other. We also found a strong signal for biomass emissions and trash burning, which is common in Nairobi's low-income areas and open-air garages. These results suggest that the large portion of urban residents in SSA who walk along roadways would benefit from air quality regulations targeting roadway emissions from diesel vehicles, dust, and trash burning. This is the first study to measure occupational exposure to urban air pollution in SSA and results imply that roadway emissions are a serious public health concern.

Occupational exposure to roadway emissions and inside informal settlements in sub-Saharan Africa: A pilot study in Nairobi, Kenya.

PubMed

Ngo, Nicole S; Gatari, Michael; Yan, Beizhan; Chillrud, Steven N; Bouhamam, Kheira; Kinneym, Patrick L

2015-06-01

Few studies examine urban air pollution in sub-Saharan Africa (SSA), yet urbanization rates there are among the highest in the world. In this study, we measured 8-hr average occupational exposure levels of fine particulate matter (PM 2.5 ), black carbon (BC), ultra violet active-particulate matter (UV-PM), and trace elements for individuals who worked along roadways in Nairobi, specifically bus drivers, garage workers, street vendors, and women who worked inside informal settlements. We found BC and re-suspended dust were important contributors to PM 2.5 levels for all study populations, particularly among bus drivers, while PM 2.5 exposure levels for garage workers, street vendors, and informal settlement residents were not statistically different from each other. We also found a strong signal for biomass emissions and trash burning, which is common in Nairobi's low-income areas and open-air garages. These results suggest that the large portion of urban residents in SSA who walk along roadways would benefit from air quality regulations targeting roadway emissions from diesel vehicles, dust, and trash burning. This is the first study to measure occupational exposure to urban air pollution in SSA and results imply that roadway emissions are a serious public health concern.

Short-Chain Chlorinated Paraffins in Zurich, Switzerland--Atmospheric Concentrations and Emissions.

PubMed

Diefenbacher, Pascal S; Bogdal, Christian; Gerecke, Andreas C; Glüge, Juliane; Schmid, Peter; Scheringer, Martin; Hungerbühler, Konrad

2015-08-18

Short-chain chlorinated paraffins (SCCPs) are of concern due to their potential for adverse health effects, bioaccumulation, persistence, and long-range transport. Data on concentrations of SCCPs in urban areas and underlying emissions are still scarce. In this study, we investigated the levels and spatial distribution of SCCPs in air, based on two separate, spatially resolved sampling campaigns in the city of Zurich, Switzerland. SCCP concentrations in air ranged from 1.8 to 17 ng·m(-3) (spring 2011) and 1.1 to 42 ng·m(-3) (spring 2013) with medians of 4.3 and 2.7 ng·m(-3), respectively. Both data sets show that atmospheric SCCP levels in Zurich can vary substantially and may be influenced by a number of localized sources within this urban area. Additionally, continuous measurements of atmospheric concentrations performed at one representative sampling site in the city center from 2011 to 2013 showed strong seasonal variations with high SCCP concentrations in summer and lower levels in winter. A long-term dynamic multimedia environmental fate model was parametrized to simulate the seasonal trends of SCCP concentrations in air and to back-calculate urban emissions. Resulting annual SCCP emissions in the city of Zurich accounted for 218-321 kg, which indicates that large SCCP stocks are present in urban areas of industrialized countries.

Air quality modelling in the Berlin-Brandenburg region using WRF-Chem v3.7.1: sensitivity to resolution of model grid and input data

NASA Astrophysics Data System (ADS)

Kuik, Friderike; Lauer, Axel; Churkina, Galina; Denier van der Gon, Hugo A. C.; Fenner, Daniel; Mar, Kathleen A.; Butler, Tim M.

2016-12-01

Air pollution is the number one environmental cause of premature deaths in Europe. Despite extensive regulations, air pollution remains a challenge, especially in urban areas. For studying summertime air quality in the Berlin-Brandenburg region of Germany, the Weather Research and Forecasting Model with Chemistry (WRF-Chem) is set up and evaluated against meteorological and air quality observations from monitoring stations as well as from a field campaign conducted in 2014. The objective is to assess which resolution and level of detail in the input data is needed for simulating urban background air pollutant concentrations and their spatial distribution in the Berlin-Brandenburg area. The model setup includes three nested domains with horizontal resolutions of 15, 3 and 1 km and anthropogenic emissions from the TNO-MACC III inventory. We use RADM2 chemistry and the MADE/SORGAM aerosol scheme. Three sensitivity simulations are conducted updating input parameters to the single-layer urban canopy model based on structural data for Berlin, specifying land use classes on a sub-grid scale (mosaic option) and downscaling the original emissions to a resolution of ca. 1 km × 1 km for Berlin based on proxy data including traffic density and population density. The results show that the model simulates meteorology well, though urban 2 m temperature and urban wind speeds are biased high and nighttime mixing layer height is biased low in the base run with the settings described above. We show that the simulation of urban meteorology can be improved when specifying the input parameters to the urban model, and to a lesser extent when using the mosaic option. On average, ozone is simulated reasonably well, but maximum daily 8 h mean concentrations are underestimated, which is consistent with the results from previous modelling studies using the RADM2 chemical mechanism. Particulate matter is underestimated, which is partly due to an underestimation of secondary organic aerosols. NOx (NO + NO2) concentrations are simulated reasonably well on average, but nighttime concentrations are overestimated due to the model's underestimation of the mixing layer height, and urban daytime concentrations are underestimated. The daytime underestimation is improved when using downscaled, and thus locally higher emissions, suggesting that part of this bias is due to deficiencies in the emission input data and their resolution. The results further demonstrate that a horizontal resolution of 3 km improves the results and spatial representativeness of the model compared to a horizontal resolution of 15 km. With the input data (land use classes, emissions) at the level of detail of the base run of this study, we find that a horizontal resolution of 1 km does not improve the results compared to a resolution of 3 km. However, our results suggest that a 1 km horizontal model resolution could enable a detailed simulation of local pollution patterns in the Berlin-Brandenburg region if the urban land use classes, together with the respective input parameters to the urban canopy model, are specified with a higher level of detail and if urban emissions of higher spatial resolution are used.

Carbon dioxide fluxes from an urban area in Beijing

NASA Astrophysics Data System (ADS)

Song, Tao; Wang, Yuesi

2012-03-01

A better understanding of urban carbon dioxide (CO 2) emissions is important for quantifying urban contributions to the global carbon budget. From January to December 2008, CO 2 fluxes were measured, by eddy covariance at 47 m above ground on a meteorological tower in a high-density residential area in Beijing. The results showed that the urban surface was a net source of CO 2 in the atmosphere. Diurnal flux patterns were similar to those previously observed in other cities and were largely influenced by traffic volume. Carbon uptake by both urban vegetation during the growing season and the reduction of fuel consumption for domestic heating resulted in less-positive daily fluxes in the summer. The average daily flux measured in the summer was 0.48 mg m - 2 s - 1 , which was 82%, 35% and 36% lower than those in the winter, spring and autumn, respectively. The reduction of vehicles on the road during the 29th Olympic and Paralympic Games had a significant impact on CO 2 flux. The flux of 0.40 mg m - 2 s - 1 for September 2008 was approximately 0.17 mg m - 2 s - 1 lower than the flux for September 2007. Annual CO 2 emissions from the study site were estimated at 20.6 kg CO 2 m - 2 y - 1 , considerably higher than yearly emissions obtained from other urban and suburban landscapes.

Air-Quality and Climate Coupling in High Resolution for Urban Heat Island Study

NASA Astrophysics Data System (ADS)

Halenka, T.; Huszar, P.; Belda, M.

2012-04-01

Recent studies show considerable effect of atmospheric chemistry and aerosols on climate on regional and local scale. For the purpose of qualifying and quantifying the magnitude of climate forcing due to atmospheric chemistry/aerosols on regional scale and climate change effects on air-quality the regional climate model RegCM and chemistry/aerosol model CAMx was coupled. Climate change impacts on air-quality have been studied in high resolution of 10km with interactive two-way coupling of the effects of air-quality on climate. The experiments with the couple were performed for EC FP7 project MEGAPOLI assessing the impact of the megacities and industrialized areas on climate. New experiments in high resolution are prepared andsimulated for Urban Heat Island studies within the OP Central Europe Project UHI. Meteorological fields generated by RCM drive CAMx transport, chemistry and a dry/wet deposition. A preprocessor utility was developed for transforming RegCM provided fields to CAMx input fields and format. There is critical issue of the emission inventories available for 10km resolution including the urban hot-spots, TNO emissions are adopted for the experiments. Sensitivity tests switching on/off urban areas emissions are analysed as well. The results for year 2005 are presented and discussed, interactive coupling is compared to study the potential of possible impact of urban air-pollution to the urban area climate.

Multi-Sensor Constrained Time Varying Emissions Estimation of Black Carbon: Attributing Urban and Fire Sources Globally

NASA Astrophysics Data System (ADS)

Cohen, J. B.

2015-12-01

The short lifetime and heterogeneous distribution of Black Carbon (BC) in the atmosphere leads to complex impacts on radiative forcing, climate, and health, and complicates analysis of its atmospheric processing and emissions. Two recent papers have estimated the global and regional emissions of BC using advanced statistical and computational methods. One used a Kalman Filter, including data from AERONET, NOAA, and other ground-based sources, to estimate global emissions of 17.8+/-5.6 Tg BC/year (with the increase attributable to East Asia, South Asia, Southeast Asia, and Eastern Europe - all regions which have had rapid urban, industrial, and economic expansion). The second additionally used remotely sensed measurements from MISR and a variance maximizing technique, uniquely quantifying fire and urban sources in Southeast Asia, as well as their large year-to-year variability over the past 12 years, leading to increases from 10% to 150%. These new emissions products, when run through our state-of-the art modelling system of chemistry, physics, transport, removal, radiation, and climate, match 140 ground stations and satellites better in both an absolute and a temporal sense. New work now further includes trace species measurements from OMI, which are used with the variance maximizing technique to constrain the types of emissions sources. Furthermore, land-use change and fire estimation products from MODIS are also included, which provide other constraints on the temporal and spatial nature of the variations of intermittent sources like fires or new permanent sources like expanded urbanization. This talk will introduce a new, top-down constrained, weekly varying BC emissions dataset, show that it produces a better fit with observations, and draw conclusions about the sources and impacts from urbanization one hand, and fires on another hand. Results specific to the Southeast and East Asia will demonstrate inter- and intra-annual variations, such as the function of the wet and dry seasons. Further, the impacts of missing data due to cloud coverage and of long-range transport from highly polluted areas to relatively clean downwind areas will be demonstrated. More general results will also be discussed in relation to the global anthropogenic aerosol distribution.

Effect of land use activities on PAH contamination in urban soils of Rawalpindi and Islamabad, Pakistan.

PubMed

Ud Din, Ikhtiar; Rashid, Audil; Mahmood, Tariq; Khalid, Azeem

2013-10-01

Urbanization can increase the vulnerability of soils to various types of contamination. Increased contamination of urban soils with polycyclic aromatic hydrocarbon (PAH) could relate to increased number of petrol pump stations and mechanical workshops-a phenomenon that needs to be constantly monitored. This study was undertaken to explore the soil PAH levels in Rawalpindi and Islamabad urban areas in relation to land use activities. Composite soil samples from petrol pump stations and mechanical workshops (n = 32) areas were evaluated for five PAHs--naphthalene, phenanthrene, pyrene, benzo[a]pyrene, and indeno(1,2,3-cd)pyrene-and compared with control area locations with minimum petroleum-related activity (n = 16). Surface samples up to 3 cm depth were collected and extraction of analytes was carried out using n-hexane and dichloromethane. Prior to running the samples, standards (100 μg ml(-1)) were run on HPLC to optimize signal to noise ratio using acetonitrile as mobile phase at a flow rate of 1.25 ml/min at 40 °C. Significant differences between petrol pump stations and mechanical workshop areas were observed for individual PAH as well as with control area soil samples. Naphthalene was found to be the most abundant PAH in soil, ranging from 2.47 to 24.36 mg kg(-1). Correlation between the benzo[a]pyrene (BaP) level in soil and the total PAH concentration (r = 0.82, P < 0.0001) revealed that BaP can be used as a potential marker for PAH pollution. A clear segregation between petrogenic and pyrogenic sources of contamination was observed when low molecular weight PAHs detected in soil was plotted against high molecular weight PAHs. The former source comprised lubricants and used engine oil found at mechanical workshops, whereas the latter could be mostly attributed to vehicular emission at petrol pumps. The results indicate that PAH contamination in urban areas of Rawalpindi and Islamabad has direct relevance with land use for petroleum activity. We conclude that in order to reduce the soil PAH exposure in urban environment, petrol pumps and mechanical workshops must be shifted to less densely populated areas because of their role as important point sources for PAH emission.

Multi-year levels and trends of non-methane hydrocarbon concentrations observed in ambient air in France

NASA Astrophysics Data System (ADS)

Waked, Antoine; Sauvage, Stéphane; Borbon, Agnès; Gauduin, Julie; Pallares, Cyril; Vagnot, Marie-Pierre; Léonardis, Thierry; Locoge, Nadine

2016-09-01

Measurements of 31 non-methane hydrocarbons (NMHCs) were carried out at three urban (Paris, 2003-2014, Strasbourg, 2002-2014 and Lyon, 2007-2014) sites in France over the period of a decade. A trend analysis was applied by means of the Mann-Kendall non-parametric test to annual and seasonal mean concentrations in order to point out changes in specific emission sources and to assess the impact of emission controls and reduction strategies. The trends were compared to those from three rural sites (Peyrusse-Vieille, 2002-2013, Tardière, 2003-2013 and Donon, 1997-2007). The results obtained showed a significant yearly decrease in pollutant concentrations over the study period and for the majority of species in the range of -1 to -7% in accordance with the decrease of NMHC emissions in France (-5 to -9%). Concentrations of long-lived species such as ethane and propane which are recognized as tracers of distant sources and natural gas remained constant. Compounds associated with combustion processes such as acetylene, propene, ethylene and benzene showed a significant decline in the range of -2% to -5% yr-1. These trends are consistent with those recently described at urban and background sites in the northern mid-latitudes and with emission inventories. C7-C9 aromatics such as toluene and xylenes as well as C4-C5 alkanes such as isopentane and isobutane also showed a significant decrease in the range of -3% to -7% yr-1. The decreasing trends in terms of % yr-1 observed at these French urban sites were typically higher for acetylene, ethylene and benzene than those reported for French rural sites of the national observatory of Measurement and Evaluation in Rural areas of trans-boundary Air pollution (MERA). The study also highlighted the difficult choice of a long term sampling site representative of the general trends of pollutant concentrations.

2001-2012 trends on air quality in Spain.

PubMed

Querol, X; Alastuey, A; Pandolfi, M; Reche, C; Pérez, N; Minguillón, M C; Moreno, T; Viana, M; Escudero, M; Orio, A; Pallarés, M; Reina, F

2014-08-15

This study aims at interpreting the 2001-2012 trends of major air pollutants in Spain, with a major focus on evaluating their relationship with those of the national emission inventories (NEI) and policy actions. Marked downward concentration trends were evidenced for PM10, PM2.5 and CO. Concentrations of NO2 and NOx also declined but in a lesser proportion at rural and traffic sites. At rural sites O3 has been kept constant, whereas it clearly increased at urban and industrial sites. Comparison of the air quality trends and major inflection points with those from NEIs, the National Energy Consumption and the calendar of the implementation of major policy actions allowed us to clearly identify major benefits of European directives on power generation and industrial sources (such as the Large Combustion Plants and the Integrated Pollution Prevention and Control Directives). This, together with a sharp 2007-2008 decrease of coal consumption has probably caused the marked parallel decline of SO2, NOx and for PM2.5 concentrations. Also the effect of the EURO 4 and 5 vehicle emission standards on decreasing emissions of PM and CO from vehicles is noticeable. The smooth decline in NO2-NOx levels is mostly attributed to the low efficiency of EURO 4 and 5 standards in reducing real life urban driving NO2 emissions. The low NOx decrease together with the complexity of the reactions of O3 formation is responsible for the constant O3 concentrations, or even the urban increase. The financial crisis has also contributed to the decrease of the ambient concentration of pollutants; however this caused a major reduction of the primary energy consumption from 2008 to 2009, and not from 2007 to 2008 when ambient air PM and SO2 sharply decreased. The meteorological influence was characterized by a 2008-2012 period favorable to the dispersion of pollutants when compared to the 2001-2007. Copyright © 2014. Published by Elsevier B.V.

Quantification of fossil fuel CO2 at the building/street level for large US cities

NASA Astrophysics Data System (ADS)

Gurney, K. R.; Razlivanov, I. N.; Song, Y.

2012-12-01

Quantification of fossil fuel CO2 emissions from the bottom-up perspective is a critical element in emerging plans on a global, integrated, carbon monitoring system (CMS). A space/time explicit emissions data product can act as both a verification and planning system. It can verify atmospheric CO2 measurements (in situ and remote) and offer detailed mitigation information to management authorities in order to optimize the mix of mitigation efforts. Here, we present the Hestia Project, an effort aimed at building a high resolution (eg. building and road link-specific, hourly) fossil fuel CO2 emissions data product for the urban domain as a pilot effort to a CMS. A complete data product has been built for the city of Indianapolis and preliminary quantification has been completed for Los Angeles and Phoenix (see figure). The effort in Indianapolis is now part of a larger effort aimed at a convergent top-down/bottom-up assessment of greenhouse gas emissions, called INFLUX. Our urban-level quantification relies on a mixture of data and modeling structures. We start with the sector-specific Vulcan Project estimate at the mix of geocoded and county-wide levels. The Hestia aim is to distribute the Vulcan result in space and time. Two components take the majority of effort: buildings and onroad emissions. In collaboration with our INFLUX colleagues, we are transporting these high resolution emissions through an atmospheric transport model for a forward comparison of the Hestia data product with atmospheric measurements, collected on aircraft and cell towers. In preparation for a formal urban-scale inversion, these forward comparisons offer insights into both improving our emissions data product and measurement strategies. A key benefit of the approach taken in this study is the tracking and archiving of fuel and process-level detail (eg. combustion process, other pollutants), allowing for a more thorough understanding and analysis of energy throughputs in the urban environment. Quantification of fossil fuel emissions, however, is one piece in a larger conception of cities as complex dynamic socio-technological systems and the Hestia effort is at the very beginning stages of connecting to the large community of research approaching cities from other perspectives and utilizing other tools. Through analysis of the three cities for which we have quantified fossil fuel CO2 emissions and recognition of the current threads emerging in urban research, we are attempting to offer insight into understanding cities via the mechanistic quantification of energy and CO2 emissions.

Predicted impact of thermal power generation emission control measures in the Beijing-Tianjin-Hebei region on air pollution over Beijing, China.

PubMed

Wang, Liqiang; Li, Pengfei; Yu, Shaocai; Mehmood, Khalid; Li, Zhen; Chang, Shucheng; Liu, Weiping; Rosenfeld, Daniel; Flagan, Richard C; Seinfeld, John H

2018-01-17

Widespread economic growth in China has led to increasing episodes of severe air pollution, especially in major urban areas. Thermal power plants represent a particularly important class of emissions. Here we present an evaluation of the predicted effectiveness of a series of recently proposed thermal power plant emission controls in the Beijing-Tianjin-Hebei (BTH) region on air quality over Beijing using the Community Multiscale Air Quality(CMAQ) atmospheric chemical transport model to predict CO, SO 2 , NO 2 , PM 2.5 , and PM 10 levels. A baseline simulation of the hypothetical removal of all thermal power plants in the BTH region is predicted to lead to 38%, 23%, 23%, 24%, and 24% reductions in current annual mean levels of CO, SO 2 , NO 2 , PM 2.5 , and PM 10 in Beijing, respectively. Similar percentage reductions are predicted in the major cities in the BTH region. Simulations of the air quality impact of six proposed thermal power plant emission reduction strategies over the BTH region provide an estimate of the potential improvement in air quality in the Beijing metropolitan area, as a function of the time of year.

Changes in land use driven by urbanization impact nitrogen cycling and the microbial community composition in soils

NASA Astrophysics Data System (ADS)

Wang, Haitao; Marshall, Christopher W.; Cheng, Minying; Xu, Huijuan; Li, Hu; Yang, Xiaoru; Zheng, Tianling

2017-03-01

Transition of populations from rural to urban living causes landscape changes and alters the functionality of soil ecosystems. It is unclear how this urbanization disturbs the microbial ecology of soils and how the disruption influences nitrogen cycling. In this study, microbial communities in turfgrass-grown soils from urban and suburban areas around Xiamen City were compared to microbial communities in the soils from rural farmlands. The potential N2O emissions, potential denitrification activity, and abundances of denitrifiers were higher in the rural farmland soils compared with the turfgrass soils. Ammonia oxidizing archaea (AOA) were more abundant than ammonia oxidizing bacteria (AOB) in turfgrass soils. Within turfgrass soils, the potential nitrification activities and AOA abundances were higher in the urban than in the suburban soils. These results indicate a more pivotal role of AOA in nitrification, especially in urban soils. Microbial community composition was distinctly grouped along urbanization categories (urban, suburban, and rural) classified according to the population density, which can in part be attributed to the differences in soil properties. These observed changes could potentially have a broader impact on soil nutrient availability and greenhouse gas emissions.

Validation of the measure automobile emissions model : a statistical analysis

DOT National Transportation Integrated Search

2000-09-01

The Mobile Emissions Assessment System for Urban and Regional Evaluation (MEASURE) model provides an external validation capability for hot stabilized option; the model is one of several new modal emissions models designed to predict hot stabilized e...

Urban-rural variations in air quality and health impacts in northern India

NASA Astrophysics Data System (ADS)

Karambelas, A. N.; Holloway, T.; Fiore, A. M.; Kinney, P.; DeFries, R. S.; Kiesewetter, G.; Heyes, C.

2017-12-01

Ambient air pollution in India is a severe problem, contributing to negative health impacts and early death. Ground-based monitors often used to quantify health impacts are often located in urban regions, however approximately 70% of India's population resides in rural areas. We use high-resolution concentrations from the regional Community Multi-scale Air Quality (CMAQ) model over densely-populated northern India to estimate air quality and health impacts due to anthropogenic emission sectors separately for urban and rural regions. Modeled concentrations inform relative risk calculations and exposure estimates as performed in the Global Burden of Disease. Anthropogenic emissions from the International Institute for Applied Systems Analysis (IIASA) Greenhouse Gas-Air Pollution Interactions and Synergies (GAINS) model following version 5a of the Evaluating the Climate and Air Quality Impacts of Short-Lived Pollutants project gridding structure are updated to reflect urban- and rural-specific activity information for transportation and residential combustion, and industrial and electrical generating unit location and magnitude information. We estimate 314,000 (95% Confidence Interval: 304,000—323,000) and 58,000 (CI: 39,000—70,000) adults (25 years or older) die prematurely each year from PM2.5 and O3 respectively in northern India, with the greatest impacts along the Indo-Gangetic Plain. Using urban and rural population distributions, we estimate that the majority of premature deaths resulting from PM2.5 and O3 are in rural (292,000) as opposed to urban (79,000) regions. These findings indicate the need for designing monitoring networks and ground-based health studies in rural areas of India to more accurately quantify the true health implications of ambient air pollution, in addition to supporting model evaluation. Using this urban-versus-rural emissions framework, we are assessing anthropogenic contributions to regional air quality and health impacts, and examining mitigation strategies to reduce anthropogenic emissions, improve air quality, and reduce PM2.5 and O3 attributable premature death in the near-term.

Los Angeles megacity: a high-resolution land–atmosphere modelling system for urban CO 2 emissions

DOE PAGES

Feng, Sha; Lauvaux, Thomas; Newman, Sally; ...

2016-07-22

Megacities are major sources of anthropogenic fossil fuel CO 2 (FFCO 2) emissions. The spatial extents of these large urban systems cover areas of 10 000 km 2 or more with complex topography and changing landscapes. We present a high-resolution land–atmosphere modelling system for urban CO 2 emissions over the Los Angeles (LA) megacity area. The Weather Research and Forecasting (WRF)-Chem model was coupled to a very high-resolution FFCO 2 emission product, Hestia-LA, to simulate atmospheric CO 2 concentrations across the LA megacity at spatial resolutions as fine as ~1 km. We evaluated multiple WRF configurations, selecting one that minimizedmore » errors in wind speed, wind direction, and boundary layer height as evaluated by its performance against meteorological data collected during the CalNex-LA campaign (May–June 2010). Our results show no significant difference between moderate-resolution (4 km) and high-resolution (1.3 km) simulations when evaluated against surface meteorological data, but the high-resolution configurations better resolved planetary boundary layer heights and vertical gradients in the horizontal mean winds. We coupled our WRF configuration with the Vulcan 2.2 (10 km resolution) and Hestia-LA (1.3 km resolution) fossil fuel CO 2 emission products to evaluate the impact of the spatial resolution of the CO 2 emission products and the meteorological transport model on the representation of spatiotemporal variability in simulated atmospheric CO 2 concentrations. We find that high spatial resolution in the fossil fuel CO 2 emissions is more important than in the atmospheric model to capture CO 2 concentration variability across the LA megacity. Finally, we present a novel approach that employs simultaneous correlations of the simulated atmospheric CO 2 fields to qualitatively evaluate the greenhouse gas measurement network over the LA megacity. Spatial correlations in the atmospheric CO 2 fields reflect the coverage of individual measurement sites when a statistically significant number of sites observe emissions from a specific source or location. We conclude that elevated atmospheric CO 2 concentrations over the LA megacity are composed of multiple fine-scale plumes rather than a single homogenous urban dome. Furthermore, we conclude that FFCO 2 emissions monitoring in the LA megacity requires FFCO 2 emissions modelling with ~1 km resolution because coarser-resolution emissions modelling tends to overestimate the observational constraints on the emissions estimates.« less

Los Angeles megacity: a high-resolution land–atmosphere modelling system for urban CO 2 emissions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Feng, Sha; Lauvaux, Thomas; Newman, Sally

Megacities are major sources of anthropogenic fossil fuel CO 2 (FFCO 2) emissions. The spatial extents of these large urban systems cover areas of 10 000 km 2 or more with complex topography and changing landscapes. We present a high-resolution land–atmosphere modelling system for urban CO 2 emissions over the Los Angeles (LA) megacity area. The Weather Research and Forecasting (WRF)-Chem model was coupled to a very high-resolution FFCO 2 emission product, Hestia-LA, to simulate atmospheric CO 2 concentrations across the LA megacity at spatial resolutions as fine as ~1 km. We evaluated multiple WRF configurations, selecting one that minimizedmore » errors in wind speed, wind direction, and boundary layer height as evaluated by its performance against meteorological data collected during the CalNex-LA campaign (May–June 2010). Our results show no significant difference between moderate-resolution (4 km) and high-resolution (1.3 km) simulations when evaluated against surface meteorological data, but the high-resolution configurations better resolved planetary boundary layer heights and vertical gradients in the horizontal mean winds. We coupled our WRF configuration with the Vulcan 2.2 (10 km resolution) and Hestia-LA (1.3 km resolution) fossil fuel CO 2 emission products to evaluate the impact of the spatial resolution of the CO 2 emission products and the meteorological transport model on the representation of spatiotemporal variability in simulated atmospheric CO 2 concentrations. We find that high spatial resolution in the fossil fuel CO 2 emissions is more important than in the atmospheric model to capture CO 2 concentration variability across the LA megacity. Finally, we present a novel approach that employs simultaneous correlations of the simulated atmospheric CO 2 fields to qualitatively evaluate the greenhouse gas measurement network over the LA megacity. Spatial correlations in the atmospheric CO 2 fields reflect the coverage of individual measurement sites when a statistically significant number of sites observe emissions from a specific source or location. We conclude that elevated atmospheric CO 2 concentrations over the LA megacity are composed of multiple fine-scale plumes rather than a single homogenous urban dome. Furthermore, we conclude that FFCO 2 emissions monitoring in the LA megacity requires FFCO 2 emissions modelling with ~1 km resolution because coarser-resolution emissions modelling tends to overestimate the observational constraints on the emissions estimates.« less

Fuels for urban transit buses: a cost-effectiveness analysis.

PubMed

Cohen, Joshua T; Hammitt, James K; Levy, Jonathan I

2003-04-15

Public transit agencies have begun to adopt alternative propulsion technologies to reduce urban transit bus emissions associated with conventional diesel (CD) engines. Among the most popular alternatives are emission controlled diesel buses (ECD), defined here to be buses with continuously regenerating diesel particle filters burning low-sulfur diesel fuel, and buses burning compressed natural gas (CNG). This study uses a series of simplifying assumptions to arrive at first-order estimates for the incremental cost-effectiveness (CE) of ECD and CNG relative to CD. The CE ratio numerator reflects acquisition and operating costs. The denominator reflects health losses (mortality and morbidity) due to primary particulate matter (PM), secondary PM, and ozone exposure, measured as quality adjusted life years (QALYs). We find that CNG provides larger health benefits than does ECD (nine vs six QALYs annually per 1000 buses) but that ECD is more cost-effective than CNG (dollar 270 000 per QALY for ECD vs dollar 1.7 million to dollar 2.4 million for CNG). These estimates are subject to much uncertainty. We identify assumptions that contribute most to this uncertainty and propose potential research directions to refine our estimates.

Increasing Intelligence in Inter-Vehicle Communications to Reduce Traffic Congestions: Experiments in Urban and Highway Environments.

PubMed

Meneguette, Rodolfo I; Filho, Geraldo P R; Guidoni, Daniel L; Pessin, Gustavo; Villas, Leandro A; Ueyama, Jó

2016-01-01

Intelligent Transportation Systems (ITS) rely on Inter-Vehicle Communication (IVC) to streamline the operation of vehicles by managing vehicle traffic, assisting drivers with safety and sharing information, as well as providing appropriate services for passengers. Traffic congestion is an urban mobility problem, which causes stress to drivers and economic losses. In this context, this work proposes a solution for the detection, dissemination and control of congested roads based on inter-vehicle communication, called INCIDEnT. The main goal of the proposed solution is to reduce the average trip time, CO emissions and fuel consumption by allowing motorists to avoid congested roads. The simulation results show that our proposed solution leads to short delays and a low overhead. Moreover, it is efficient with regard to the coverage of the event and the distance to which the information can be propagated. The findings of the investigation show that the proposed solution leads to (i) high hit rate in the classification of the level of congestion, (ii) a reduction in average trip time, (iii) a reduction in fuel consumption, and (iv) reduced CO emissions.

Increasing Intelligence in Inter-Vehicle Communications to Reduce Traffic Congestions: Experiments in Urban and Highway Environments

PubMed Central

Filho, Geraldo P. R.; Guidoni, Daniel L.; Pessin, Gustavo; Villas, Leandro A.; Ueyama, Jó

2016-01-01

Intelligent Transportation Systems (ITS) rely on Inter-Vehicle Communication (IVC) to streamline the operation of vehicles by managing vehicle traffic, assisting drivers with safety and sharing information, as well as providing appropriate services for passengers. Traffic congestion is an urban mobility problem, which causes stress to drivers and economic losses. In this context, this work proposes a solution for the detection, dissemination and control of congested roads based on inter-vehicle communication, called INCIDEnT. The main goal of the proposed solution is to reduce the average trip time, CO emissions and fuel consumption by allowing motorists to avoid congested roads. The simulation results show that our proposed solution leads to short delays and a low overhead. Moreover, it is efficient with regard to the coverage of the event and the distance to which the information can be propagated. The findings of the investigation show that the proposed solution leads to (i) high hit rate in the classification of the level of congestion, (ii) a reduction in average trip time, (iii) a reduction in fuel consumption, and (iv) reduced CO emissions PMID:27526048

Effectiveness of green infrastructure for improvement of air quality in urban street canyons.

PubMed

Pugh, Thomas A M; Mackenzie, A Robert; Whyatt, J Duncan; Hewitt, C Nicholas

2012-07-17

Street-level concentrations of nitrogen dioxide (NO(2)) and particulate matter (PM) exceed public health standards in many cities, causing increased mortality and morbidity. Concentrations can be reduced by controlling emissions, increasing dispersion, or increasing deposition rates, but little attention has been paid to the latter as a pollution control method. Both NO(2) and PM are deposited onto surfaces at rates that vary according to the nature of the surface; deposition rates to vegetation are much higher than those to hard, built surfaces. Previously, city-scale studies have suggested that deposition to vegetation can make a very modest improvement (<5%) to urban air quality. However, few studies take full account of the interplay between urban form and vegetation, specifically the enhanced residence time of air in street canyons. This study shows that increasing deposition by the planting of vegetation in street canyons can reduce street-level concentrations in those canyons by as much as 40% for NO(2) and 60% for PM. Substantial street-level air quality improvements can be gained through action at the scale of a single street canyon or across city-sized areas of canyons. Moreover, vegetation will continue to offer benefits in the reduction of pollution even if the traffic source is removed from city centers. Thus, judicious use of vegetation can create an efficient urban pollutant filter, yielding rapid and sustained improvements in street-level air quality in dense urban areas.

Diurnal, synoptic and seasonal variability of atmospheric CO2 in the Paris megacity area

NASA Astrophysics Data System (ADS)

Xueref-Remy, Irène; Dieudonné, Elsa; Vuillemin, Cyrille; Lopez, Morgan; Lac, Christine; Schmidt, Martina; Delmotte, Marc; Chevallier, Frédéric; Ravetta, François; Perrussel, Olivier; Ciais, Philippe; Bréon, François-Marie; Broquet, Grégoire; Ramonet, Michel; Spain, T. Gerard; Ampe, Christophe

2018-03-01

Most of the global fossil fuel CO2 emissions arise from urbanized and industrialized areas. Bottom-up inventories quantify them but with large uncertainties. In 2010-2011, the first atmospheric in situ CO2 measurement network for Paris, the capital of France, began operating with the aim of monitoring the regional atmospheric impact of the emissions coming from this megacity. Five stations sampled air along a northeast-southwest axis that corresponds to the direction of the dominant winds. Two stations are classified as rural (Traînou - TRN; Montgé-en-Goële - MON), two are peri-urban (Gonesse - GON; Gif-sur-Yvette - GIF) and one is urban (EIF, located on top of the Eiffel Tower). In this study, we analyze the diurnal, synoptic and seasonal variability of the in situ CO2 measurements over nearly 1 year (8 August 2010-13 July 2011). We compare these datasets with remote CO2 measurements made at Mace Head (MHD) on the Atlantic coast of Ireland and support our analysis with atmospheric boundary layer height (ABLH) observations made in the center of Paris and with both modeled and observed meteorological fields. The average hourly CO2 diurnal cycles observed at the regional stations are mostly driven by the CO2 biospheric cycle, the ABLH cycle and the proximity to urban CO2 emissions. Differences of several µmol mol-1 (ppm) can be observed from one regional site to the other. The more the site is surrounded by urban sources (mostly residential and commercial heating, and traffic), the more the CO2 concentration is elevated, as is the associated variability which reflects the variability of the urban sources. Furthermore, two sites with inlets high above ground level (EIF and TRN) show a phase shift of the CO2 diurnal cycle of a few hours compared to lower sites due to a strong coupling with the boundary layer diurnal cycle. As a consequence, the existence of a CO2 vertical gradient above Paris can be inferred, whose amplitude depends on the time of the day and on the season, ranging from a few tenths of ppm during daytime to several ppm during nighttime. The CO2 seasonal cycle inferred from monthly means at our regional sites is driven by the biospheric and anthropogenic CO2 flux seasonal cycles, the ABLH seasonal cycle and also synoptic variations. Enhancements of several ppm are observed at peri-urban stations compared to rural ones, mostly from the influence of urban emissions that are in the footprint of the peri-urban station. The seasonal cycle observed at the urban station (EIF) is specific and very sensitive to the ABLH cycle. At both the diurnal and the seasonal scales, noticeable differences of several ppm are observed between the measurements made at regional rural stations and the remote measurements made at MHD, that are shown not to define background concentrations appropriately for quantifying the regional ( ˜ 100 km) atmospheric impact of urban CO2 emissions. For wind speeds less than 3 m s-1, the accumulation of local CO2 emissions in the urban atmosphere forms a dome of several tens of ppm at the peri-urban stations, mostly under the influence of relatively local emissions including those from the Charles de Gaulle (CDG) Airport facility and from aircraft in flight. When wind speed increases, ventilation transforms the CO2 dome into a plume. Higher CO2 background concentrations of several ppm are advected from the remote Benelux-Ruhr and London regions, impacting concentrations at the five stations of the network even at wind speeds higher than 9 m s-1. For wind speeds ranging between 3 and 8 m s-1, the impact of Paris emissions can be detected in the peri-urban stations when they are downwind of the city, while the rural stations often seem disconnected from the city emission plume. As a conclusion, our study highlights a high sensitivity of the stations to wind speed and direction, to their distance from the city, but also to the ABLH cycle depending on their elevation. We learn some lessons regarding the design of an urban CO2 network: (1) careful attention should be paid to properly setting regional (˜ 100 km) background sites that will be representative of the different wind sectors; (2) the downwind stations should be positioned as symmetrically as possible in relation to the city center, at the peri-urban/rural border; (3) the stations should be installed at ventilated sites (away from strong local sources) and the air inlet set up above the building or biospheric canopy layer, whichever is the highest; and (4) high-resolution wind information should be available with the CO2 measurements.

Chemical characterization and source identification of PM2.5 at multiple sites in the Beijing-Tianjin-Hebei region, China

NASA Astrophysics Data System (ADS)

Huang, Xiaojuan; Liu, Zirui; Liu, Jingyun; Hu, Bo; Wen, Tianxue; Tang, Guiqian; Zhang, Junke; Wu, Fangkun; Ji, Dongsheng; Wang, Lili; Wang, Yuesi

2017-11-01

The simultaneous observation and analysis of atmospheric fine particles (PM2.5) on a regional scale is an important approach to develop control strategies for haze pollution. In this study, samples of filtered PM2.5 were collected simultaneously at three urban sites (Beijing, Tianjin, and Shijiazhuang) and at a regional background site (Xinglong) in the Beijing-Tianjin-Hebei (BTH) region from June 2014 to April 2015. The PM2.5 at the four sites was mainly comprised of organic matter, secondary inorganic ions, and mineral dust. Positive matrix factorization (PMF) demonstrated that, on an annual basis, secondary inorganic aerosol was the largest PM2.5 source in this region, accounting for 29.2-40.5 % of the PM2.5 mass at the urban sites; the second-largest PM2.5 source was motor vehicle exhaust, particularly in Beijing (24.9 %), whereas coal combustion was also a large source in Tianjin (12.4 %) and Shijiazhuang (15.5 %), with particular dominance in winter. Secondary inorganic aerosol plays a vital role in the haze process, with the exception of the spring haze in Shijiazhuang and Tianjin, for which the dust source was crucial. In addition to secondary transformations, local direct emissions (coal combustion and motor vehicle exhaust) significantly contribute to the winter haze at the urban sites. Moreover, with the aggravation of haze pollution, the OC / EC mass ratio of PM2.5 decreased considerably and the nitrate-rich secondary aerosol increased during all four seasons in Beijing, both of which indicate that local motor vehicle emissions significantly contribute to the severe haze episodes in Beijing. To assess the impacts of regional transport on haze pollution, the PMF results were further processed with backward-trajectory cluster analysis, revealing that haze pollution usually occurred when air masses originating from polluted industrial regions in the south prevailed and is characterized by high PM2.5 loadings with considerable contributions from secondary aerosols. This study suggests that control strategies to mitigate haze pollution in the BTH region should focus on the reduction of gaseous precursor emissions from fossil fuel combustion (motor vehicle emissions in Beijing and coal combustion in Tianjin, Hebei, and nearby provinces).

Simultaneous measurements of particle number size distributions at ground level and 260 m on a meteorological tower in urban Beijing, China

NASA Astrophysics Data System (ADS)

Du, Wei; Zhao, Jian; Wang, Yuying; Zhang, Yingjie; Wang, Qingqing; Xu, Weiqi; Chen, Chen; Han, Tingting; Zhang, Fang; Li, Zhanqing; Fu, Pingqing; Li, Jie; Wang, Zifa; Sun, Yele

2017-06-01

Despite extensive studies into the characterization of particle number size distributions at ground level, real-time measurements above the urban canopy in the megacity of Beijing have never been performed to date. Here we conducted the first simultaneous measurements of size-resolved particle number concentrations at ground level and 260 m in urban Beijing from 22 August to 30 September. Our results showed overall similar temporal variations in number size distributions between ground level and 260 m, yet periods with significant differences were also observed. Particularly, accumulation-mode particles were highly correlated (r2 = 0. 85) at the two heights, while Aitken-mode particles presented more differences. Detailed analysis suggests that the vertical differences in number concentrations strongly depended on particle size, and particles with a mobility diameter between 100 and 200 nm generally showed higher concentrations at higher altitudes. Particle growth rates and condensation sinks were also calculated, which were 3.2 and 3.6 nm h-1, and 2.8 × 10-2 and 2.9 × 10-2 s-1, at ground level and 260 m, respectively. By linking particle growth with aerosol composition, we found that organics appeared to play an important role in the early stage of the growth (09:00-12:00 LT) while sulfate was also important during the later period. Positive matrix factorization of size-resolved number concentrations identified three common sources at ground level and 260 m, including a factor associated with new particle formation and growth events (NPEs), and two secondary factors that represent photochemical processing and regional transport. Cooking emission was found to have a large contribution to small particles and showed much higher concentration at ground level than 260 m in the evening. These results imply that investigation of NPEs at ground level in megacities needs to consider the influences of local cooking emissions. The impacts of regional emission controls on particle number concentrations were also illustrated. Our results showed that regional emission controls have a dominant impact on accumulation-mode particles by decreasing gas precursors and particulate matter loadings, and hence suppressing particle growth. In contrast, the influences on Aitken particles were much smaller due to the enhanced new particle formation (NPF) events.

Diuranl variations and characteristics of organic molecular composition and stable carbon isotope ratios of PM2.5 in Beijing during the "APEC Blue"

NASA Astrophysics Data System (ADS)

Ren, H.; Fan, S.; Fu, P.

2016-12-01

Fine particulate matters (PM2.5) were collected before and during the 2014 Asian-Pacific Economic Cooperation (2014 APEC) (15 October-12 November) in Beijing to study their sources, diurnal variations, and the effects of region controls on the improving of the air quality. Organic molecular compositions of lipids, saccharides, polyacids, ligin & resin products, aromatic acids, phthalate esters, hopanes, PAHs and sterols were analyzed by GC-MS), while stable carbon isotope ratio (δ13C) of total carbon (TC) were determination using Gas Isotope Ratio MS (IRMS, MAT 253). Results indicated that five aerosol episodes were founded before and during the APEC event. Concentrations of most organic compounds showed maxima at nighttime and were obviously decreased during the APEC. These features were associated with meteorological conditions (especially high relative humidity and low wind speed), reginal emission controls (carried out during APEC), urban boundary layer movement and mountain/valley breezes in Beijing. Before the APEC, the main sources of organic aerosols in Beijing were long-range transport from surrounding cities together with local emission sources, while local emissions became the dominant source during the APEC. Biomass burning, motor emissions, fossil fuel combustion such as coal and petroleum, open-burning of municipal wastes during night significantly contributed to organic aerosols in Beijing. Our results suggest that anthropogenic emissions are important sources of aerosols in Beijing, and the regional controls is an efficient way to improve the air quality.

Carbon dynamics and sequestration in urban turfgrass ecosystems

USDA-ARS?s Scientific Manuscript database

Urbanization is a global trend. Turfgrass covers 1.9% of land in the continental US. Here we review existing literature associated with carbon (C) pools, sequestration, and nitrous oxide emission of urban turfgrass ecosystems. Turfgrasses exhibit significant carbon sequestration (0.34–1.4 Mg ha-1 ye...

[Comparison Analysis of Economic and Engineering Control of Industrial VOCs].

PubMed

Wang, Yu-fei; Liu, Chang-xin; Cheng, Jie; Hao, Zheng-ping; Wang, Zheng

2015-04-01

Volatile organic compounds (VOCs) pollutant has become China's major air pollutant in key urban areas like sulfur dioxide, nitrogen oxides and particulate matter. It is mainly produced from industry sectors, and engineering control is one of the most important reduction measures. During the 12th Five-Year Plan, China decides to invest 40 billion RMB to build pollution control projects in key industry sectors with annual emission reduction of 605 000 t x a(-1). It shows that China attaches a great importance to emission reduction by engineering projects and highlights the awareness of engineering reduction technologies. In this paper, a macroeconomic model, namely computable general equilibrium model, (CGE model) was employed to simulate engineering control and economic control (imposing environmental tax). We aim to compare the pros and cons of the two reduction policies. Considering the economic loss of the whole country, the environmental tax has more impacts on the economy system than engineering reduction measures. We suggest that the central government provides 7 500 RMB x t(-1) as subsidy for enterprises in industry sectors to encourage engineering reduction.

Source Characterization of Volatile Organic Compounds Affecting the Air Quality in a Coastal Urban Area of South Texas

PubMed Central

Sanchez, Marciano; Karnae, Saritha; John, Kuruvilla

2008-01-01

Selected Volatile Organic Compounds (VOC) emitted from various anthropogenic sources including industries and motor vehicles act as primary precursors of ozone, while some VOC are classified as air toxic compounds. Significantly large VOC emission sources impact the air quality in Corpus Christi, Texas. This urban area is located in a semi-arid region of South Texas and is home to several large petrochemical refineries and industrial facilities along a busy ship-channel. The Texas Commission on Environmental Quality has setup two continuous ambient monitoring stations (CAMS 633 and 634) along the ship channel to monitor VOC concentrations in the urban atmosphere. The hourly concentrations of 46 VOC compounds were acquired from TCEQ for a comprehensive source apportionment study. The primary objective of this study was to identify and quantify the sources affecting the ambient air quality within this urban airshed. Principal Component Analysis/Absolute Principal Component Scores (PCA/APCS) was applied to the dataset. PCA identified five possible sources accounting for 69% of the total variance affecting the VOC levels measured at CAMS 633 and six possible sources affecting CAMS 634 accounting for 75% of the total variance. APCS identified natural gas emissions to be the major source contributor at CAMS 633 and it accounted for 70% of the measured VOC concentrations. The other major sources identified at CAMS 633 included flare emissions (12%), fugitive gasoline emissions (9%), refinery operations (7%), and vehicle exhaust (2%). At CAMS 634, natural gas sources were identified as the major source category contributing to 31% of the observed VOC. The other sources affecting this site included: refinery operations (24%), flare emissions (22%), secondary industrial processes (12%), fugitive gasoline emissions (8%) and vehicle exhaust (3%). PMID:19139530

VOC species and emission inventory from vehicles and their SOA formation potentials estimation in Shanghai, China

NASA Astrophysics Data System (ADS)

Huang, C.; Wang, H. L.; Li, L.; Wang, Q.; Lu, Q.; de Gouw, J. A.; Zhou, M.; Jing, S. A.; Lu, J.; Chen, C. H.

2015-10-01

Volatile organic compound (VOC) species from vehicle exhausts and gas evaporation were investigated by chassis dynamometer and on-road measurements of nine gasoline vehicles, seven diesel vehicles, five motorcycles, and four gas evaporation samples. The secondary organic aerosol (SOA) mass yields of gasoline, diesel, motorcycle exhausts, and gas evaporation were estimated based on the mixing ratio of measured C2-C12 VOC species and inferred carbon number distributions. High aromatic contents were measured in gasoline exhausts and contributed comparatively more SOA yield. A vehicular emission inventory was compiled based on a local survey of on-road traffic in Shanghai and real-world measurements of vehicle emission factors from previous studies in the cities of China. The inventory-based vehicular organic aerosol (OA) productions to total CO emissions were compared with the observed OA to CO concentrations (ΔOA / ΔCO) in the urban atmosphere. The results indicate that vehicles dominate the primary organic aerosol (POA) emissions and OA production, which contributed about 40 and 60 % of OA mass in the urban atmosphere of Shanghai. Diesel vehicles, which accounted for less than 20 % of vehicle kilometers of travel (VKT), contribute more than 90 % of vehicular POA emissions and 80-90 % of OA mass derived by vehicles in urban Shanghai. Gasoline exhaust could be an important source of SOA formation. Tightening the limit of aromatic content in gasoline fuel will be helpful to reduce its SOA contribution. Intermediate-volatile organic compounds (IVOCs) in vehicle exhausts greatly contribute to SOA formation in the urban atmosphere of China. However, more experiments need to be conducted to determine the contributions of IVOCs to OA pollution in China.

Detecting small scale CO2 emission structures using OCO-2

NASA Astrophysics Data System (ADS)

Schwandner, Florian M.; Eldering, Annmarie; Verhulst, Kristal R.; Miller, Charles E.; Nguyen, Hai M.; Oda, Tomohiro; O'Dell, Christopher; Rao, Preeti; Kahn, Brian; Crisp, David; Gunson, Michael R.; Sanchez, Robert M.; Ashok, Manasa; Pieri, David; Linick, Justin P.; Yuen, Karen

2016-04-01

Localized carbon dioxide (CO2) emission structures cover spatial domains of less than 50 km diameter and include cities and transportation networks, as well as fossil fuel production, upgrading and distribution infra-structure. Anthropogenic sources increasingly upset the natural balance between natural carbon sources and sinks. Mitigation of resulting climate change impacts requires management of emissions, and emissions management requires monitoring, reporting and verification. Space-borne measurements provide a unique opportunity to detect, quantify, and analyze small scale and point source emissions on a global scale. NASA's first satellite dedicated to atmospheric CO2 observation, the July 2014 launched Orbiting Carbon Observatory (OCO-2), now leads the afternoon constellation of satellites (A-Train). Its continuous swath of 2 to 10 km in width and eight footprints across can slice through coincident emission plumes and may provide momentary cross sections. First OCO-2 results demonstrate that we can detect localized source signals in the form of urban total column averaged CO2 enhancements of ~2 ppm against suburban and rural backgrounds. OCO-2's multi-sounding swath observing geometry reveals intra-urban spatial structures reflected in XCO2 data, previously unobserved from space. The transition from single-shot GOSAT soundings detecting urban/rural differences (Kort et al., 2012) to hundreds of soundings per OCO-2 swath opens up the path to future capabilities enabling urban tomography of greenhouse gases. For singular point sources like coal fired power plants, we have developed proxy detections of plumes using bands of imaging spectrometers with sensitivity to SO2 in the thermal infrared (ASTER). This approach provides a means to automate plume detection with subsequent matching and mining of OCO-2 data for enhanced detection efficiency and validation. © California Institute of Technology

Determining air quality and greenhouse gas impacts of hydrogen infrastructure and fuel cell vehicles.

PubMed

Stephens-Romero, Shane; Carreras-Sospedra, Marc; Brouwer, Jacob; Dabdub, Donald; Samuelsen, Scott

2009-12-01

Adoption of hydrogen infrastructure and hydrogen fuel cell vehicles (HFCVs) to replace gasoline internal combustion engine (ICE) vehicles has been proposed as a strategy to reduce criteria pollutant and greenhouse gas (GHG) emissions from the transportation sector and transition to fuel independence. However, it is uncertain (1) to what degree the reduction in criteria pollutants will impact urban air quality, and (2) how the reductions in pollutant emissions and concomitant urban air quality impacts compare to ultralow emission gasoline-powered vehicles projected for a future year (e.g., 2060). To address these questions, the present study introduces a "spatially and temporally resolved energy and environment tool" (STREET) to characterize the pollutant and GHG emissions associated with a comprehensive hydrogen supply infrastructure and HFCVs at a high level of geographic and temporal resolution. To demonstrate the utility of STREET, two spatially and temporally resolved scenarios for hydrogen infrastructure are evaluated in a prototypical urban airshed (the South Coast Air Basin of California) using geographic information systems (GIS) data. The well-to-wheels (WTW) GHG emissions are quantified and the air quality is established using a detailed atmospheric chemistry and transport model followed by a comparison to a future gasoline scenario comprised of advanced ICE vehicles. One hydrogen scenario includes more renewable primary energy sources for hydrogen generation and the other includes more fossil fuel sources. The two scenarios encompass a variety of hydrogen generation, distribution, and fueling strategies. GHG emissions reductions range from 61 to 68% for both hydrogen scenarios in parallel with substantial improvements in urban air quality (e.g., reductions of 10 ppb in peak 8-h-averaged ozone and 6 mug/m(3) in 24-h-averaged particulate matter concentrations, particularly in regions of the airshed where concentrations are highest for the gasoline scenario).

Understanding NOx emission trends in China based on OMI observations

NASA Astrophysics Data System (ADS)

Wang, Y.; Ga, D.; Smeltzer, C. D.; Yi, R.; Liu, Z.

2012-12-01

We analyze OMI observations of NO2 columns over China from 2005 to 2010. Simulations using a regional 3-D chemical transport model (REAM) are used to derive the top-down anthropogenic NOx emissions. The Kendall method is then applied to derive the emission trend. The emission trend is affected by the economic slowdown in 2009. After removing the effect of one year abnormal data, the overall emission trend is 4.35±1.42% per year, which is slower than the linear-regression trend of 5.8-10.8% per year reported for previous years. We find large regional, seasonal, and urban-rural variations in emission trend. The annual emission trends of Northeast China, Central China Plain, Yangtze River Delta and Pearl River Delta are 44.98±1.39%, 5.24±1.63%, 3.31±1.02% and -4.02±1.87%, respectively. The annual emission trends of four megacities, Beijing, Shanghai, Guangzhou and Shenzhen are 0.7±0.27%, -0.75±0.31%, -4.08±1.21% and -6.22±2.85%,, considerably lower than the regional averages. These results appear to suggest that a number of factors, including migration of high-emission industries, vehicle emission regulations, emission control measures of thermal power plants, increased hydro-power usage, have reduced or reversed the increasing trend of NOx emissions in more economically developed megacities and southern coastal regions.

Source diagnostics of polycyclic aromatic hydrocarbons in urban road runoff, dust, rain and canopy throughfall.

PubMed

Zhang, Wei; Zhang, Shucai; Wan, Chao; Yue, Dapan; Ye, Youbin; Wang, Xuejun

2008-06-01

Diagnostic ratios and multivariate analysis were utilized to apportion polycyclic aromatic hydrocarbon (PAH) sources for road runoff, road dust, rain and canopy throughfall based on samples collected in an urban area of Beijing, China. Three sampling sites representing vehicle lane, bicycle lane and branch road were selected. For road runoff and road dust, vehicular emission and coal combustion were identified as major sources, and the source contributions varied among the sampling sites. For rain, three principal components were apportioned representing coal/oil combustion (54%), vehicular emission (34%) and coking (12%). For canopy throughfall, vehicular emission (56%), coal combustion (30%) and oil combustion (14%) were identified as major sources. Overall, the PAH's source for road runoff mainly reflected that for road dust. Despite site-specific sources, the findings at the study area provided a general picture of PAHs sources for the road runoff system in urban area of Beijing.

The estimated impact of California’s urban water conservation mandate on electricity consumption and greenhouse gas emissions

NASA Astrophysics Data System (ADS)

Spang, Edward S.; Holguin, Andrew J.; Loge, Frank J.

2018-01-01

In April 2015, the Governor of California mandated a 25% statewide reduction in water consumption (relative to 2013 levels) by urban water suppliers. The more than 400 public water agencies affected by the regulation were also required to report monthly progress towards the conservation goal to the State Water Resources Control Board. This paper uses the reported data to assess how the water utilities have responded to this mandate and to estimate the electricity savings and greenhouse gas (GHG) emissions reductions associated with reduced operation of urban water infrastructure systems. The results show that California succeeded in saving 524 000 million gallons (MG) of water (a 24.5% decrease relative to the 2013 baseline) over the mandate period, which translates into 1830 GWh total electricity savings, and a GHG emissions reduction of 521 000 metric tonnes of carbon dioxide equivalents (MT CO2e). For comparison, the total electricity savings linked to water conservation are approximately 11% greater than the savings achieved by the investor-owned electricity utilities’ efficiency programs for roughly the same time period, and the GHG savings represent the equivalent of taking about 111 000 cars off the road for a year. These indirect, large-scale electricity and GHG savings were achieved at costs that were competitive with existing programs that target electricity and GHG savings directly and independently. Finally, given the breadth of the results produced, we built a companion website, called ‘H2Open’ (https://cwee.shinyapps.io/greengov/), to this research effort that allows users to view and explore the data and results across scales, from individual water utilities to the statewide summary.

Assessment of hydrogen sulfide emission from a sewage treatment plant using AERMOD.

PubMed

Baawain, Mahad; Al-Mamun, Abdullah; Omidvarborna, Hamid; Al-Jabri, Abdullah

2017-06-01

Air quality modeling plays an important role in prediction of air pollutants in urban areas. Moreover, it is also an essential component to make crucial decisions in environmental management. In this study, environmental protection agency (EPA) regulatory model (AERMOD) was implemented in order to assess the urban air quality in the city of Muscat, Sultanate of Oman. Dispersion modeling was employed for the prediction of hydrogen sulfide (H 2 S) emissions, a neighborhood claimed issue, from Al-Ansab sewage treatment plant (STP). Meteorological, elevation data, and H 2 S survey results were implemented into the model. From the site survey study, four different H 2 S emission sources were identified as sewage tanker connection points, biofilter, old odor control unit (OCU), and open channels of raw sewage. It was observed that based on maximum 24-h analysis, the ground level concentration outside the STP exceeded the concentration limit, 40 μg/m 3 , recommended by the local regulating agency in Oman. By applying a sensitivity analysis study, the locations with the highest predicted H 2 S levels were identified. The most affected area in the worst-case scenario was the nearby expressway with 450.9 μg/m 3 of H 2 S. The highest ground level concentration of H 2 S was detected in March, while the lowest was measured in December. The model also predicted that the impact of odor nuisance is greater at the summer season than that of other seasons due to the elevated temperatures. The study revealed an adverse environmental impact from the STPs on urban air quality, which may pose a threat to the public health.

Analysis of the potential of near ground measurements of CO2 and CH4 in London, UK for the monitoring of city-scale emissions using an atmospheric transport model

NASA Astrophysics Data System (ADS)

Boon, A.; Broquet, G.; Clifford, D. J.; Chevallier, F.; Butterfield, D. M.; Pison, I.; Ramonet, M.; Paris, J. D.; Ciais, P.

2015-11-01

Carbon dioxide (CO2) and methane (CH4) mole fractions were measured at four near ground sites located in and around London during the summer of 2012 in view to investigate the potential of assimilating such measurements in an atmospheric inversion system for the monitoring of the CO2 and CH4 emissions in the London area. These data were analysed and compared with simulations using a modelling framework suited to building an inversion system: a 2 km horizontal resolution South of England configuration of the transport model CHIMERE driven by European Centre for Medium-Range Weather Forecasting (ECMWF) meteorological forcing, coupled to a 1 km horizontal resolution emission inventory (the UK National Atmospheric Emission Inventory). First comparisons reveal that local sources have a large impact on measurements and these local sources cannot be represented in the model at 2 km resolution. We evaluate methods to minimise some of the other critical sources of misfits between the observation data and the model simulation that overlap the signature of the errors in the emission inventory. These methods should make it easier to identify the corrections that should be applied to the inventory. Analysis is supported by observations from meteorological sites around the city and a three-week period of atmospheric mixing layer height estimations from lidar measurements. The difficulties of modelling the mixing layer depth and thus CO2 and CH4 concentrations during the night, morning and late afternoon led us to focus on the afternoon period for all further analyses. The misfits between observations and model simulations are high for both CO2 and CH4 (i.e., their root mean square (RMS) is between 8 and 12 parts per million (ppm) for CO2 and between 30 and 55 parts per billion (ppb) for CH4 at a given site). By analysing the gradients between the urban sites and a suburban or rural reference site, we are able to decrease the impact of uncertainties in the fluxes and transport outside the London area and in the model domain boundary conditions, and to better focus attention on the signature of London urban CO2 and CH4 emissions. This considerably improves the statistical agreement between the model and observations for CO2 (model-data RMS misfit of between 3 and 7 ppm) and to a lesser degree for CH4 (model-data RMS misfit of between 29 and 38 ppb). Between one of the urban sites and either reference site, selecting the gradients during periods wherein the reference site is upwind of the urban site further decreases the statistics of the misfits in general even though not systematically. In a final attempt to focus on the signature of the city anthropogenic emission in the mole fraction measurements, we use a theoretical ratio of gradients of CO to gradients of CO2 from fossil fuel emissions in the London area to diagnose observation based fossil fuel CO2 gradients, and compare them with the modelled ones. This estimate increases the consistency between the model and the measurements when considering one of the urban sites, but not when considering the other. While this study evaluates different approaches for increasing the consistency between the mesoscale model and the near ground data, and manages to decrease the random component of the analysed model data misfits to an extent that should not be prohibitive to extracting the signal from the London urban emissions, large biases remain in the final misfits. These biases are likely to be due to local emissions, to which the urban near ground sites are highly sensitive. This questions our current ability to exploit urban near ground data for the atmospheric inversion of city emissions based on models at spatial resolution coarser than 2 km.

Wastewater treatment and reuse in urban agriculture: exploring the food, energy, water, and health nexus in Hyderabad, India

NASA Astrophysics Data System (ADS)

Miller-Robbie, Leslie; Ramaswami, Anu; Amerasinghe, Priyanie

2017-07-01

Nutrients and water found in domestic treated wastewater are valuable and can be reutilized in urban agriculture as a potential strategy to provide communities with access to fresh produce. In this paper, this proposition is examined by conducting a field study in the rapidly developing city of Hyderabad, India. Urban agriculture trade-offs in water use, energy use and GHG emissions, nutrient uptake, and crop pathogen quality are evaluated, and irrigation waters of varying qualities (treated wastewater, versus untreated water and groundwater) are compared. The results are counter-intuitive, and illustrate potential synergies and key constraints relating to the food-energy-water-health (FEW-health) nexus in developing cities. First, when the impact of GHG emissions from untreated wastewater diluted in surface streams is compared with the life cycle assessment of wastewater treatment with reuse in agriculture, the treatment-plus-reuse case yields a 33% reduction in life cycle system-wide GHG emissions. Second, despite water cycling benefits in urban agriculture, only <1% of the nutrients are able to be captured in urban agriculture, limited by the small proportion of effluent divertible to urban agriculture due to land constraints. Thus, water treatment plus reuse in urban farms can enhance GHG mitigation and also directly save groundwater; however, very large amounts of land are needed to extract nutrients from dilute effluents. Third, although energy use for wastewater treatment results in pathogen indicator organism concentrations in irrigation water to be reduced by 99.9% (three orders of magnitude) compared to the untreated case, crop pathogen content was reduced by much less, largely due to environmental contamination and farmer behavior and harvesting practices. The study uncovers key physical, environmental, and behavioral factors that constrain benefits achievable at the FEW-health nexus in urban areas.

Chemical and stable carbon isotopic composition of PM2.5 from on-road vehicle emissions in the PRD region and implication for vehicle emission control policy

NASA Astrophysics Data System (ADS)

Dai, S.; Bi, X.; Chan, L. Y.; He, J.; Wang, B.; Wang, X.; Sheng, G.; Fu, J.

2014-11-01

Vehicle emission is a major source of urban air pollution. In recent decade, the Chinese government has introduced a range of policies to reduce the vehicle emission. In order to understand the chemical characteristics of PM2.5 from on-road vehicle emission in the Pearl River Delta (PRD) region and to evaluate the effectiveness of control policies on vehicles emission, the emission factors of PM2.5 mass, elemental carbon (EC), organic carbon (OC), water-soluble organic carbon (WSOC), water-soluble inorganic ions (WSII), metal elements, organic compounds and stable carbon isotopic composition were measured in the Zhujiang Tunnel of Guangzhou, the PRD region of China in 2013. Emission factors of PM2.5 mass, OC, EC, and WSOC were 92.4, 16.7, 16.4, and 1.31 mg vehicle-1 km-1 respectively. Emission factors of WSII were 0.016 (F-) ~4.17 (Cl-) mg vehicle-1 km-1, totally contributing about 9.8% to the PM2.5 emissions. The sum of 27 measured metal elements accounted for 15.2% of the PM2.5 emissions. Fe was the most abundant metal element, with an emission factor of 3.91 mg vehicle-1 km-1. Emission factors of organic compounds including n-alkanes, PAHs, hopanes, and steranes were 91.9, 5.02, 32.0 and 7.59 μg vehicle-1 km-1, respectively. Stable carbon isotopic composition δ13C value was measured and it was -25.0‰ on average. An isotopic fractionation of 3.2‰ was found during fuel combustion. Compared with a previous study in Zhujiang Tunnel in year 2004, emission factors of PM2.5 mass, EC, OC, WSII except Cl-, and organic compounds decreased by 16.0-93.4%, which could be attributed to emission control policy from 2004 to 2013. However, emission factors of most of the metal elements increased significantly, which could be partially attributed to the changes in motor oil additives and vehicle condition. There are no mandatory national standards to limit metal content from vehicle emission, which should be a concern of the government. A snapshot of the 2013 characteristic emission of PM2.5 and its constituents from on-road vehicular fleet in the PRD region retrieved from our study was found to be useful for the assessment of past and future implementation of vehicle emission control policy.

Chemical and stable carbon isotopic composition of PM2.5 from on-road vehicle emissions in the PRD region and implications for vehicle emission control policy

NASA Astrophysics Data System (ADS)

Dai, S.; Bi, X.; Chan, L. Y.; He, J.; Wang, B.; Wang, X.; Peng, P.; Sheng, G.; Fu, J.

2015-03-01

Vehicle emissions are a major source of urban air pollution. In recent decade, the Chinese government has introduced a range of policies to reduce vehicle emissions. In order to understand the chemical characteristics of PM2.5 from on-road vehicle emissions in the Pearl River Delta (PRD) region and to evaluate the effectiveness of control policies on vehicle emissions, the emission factors of PM2.5 mass, elemental carbon (EC), organic carbon (OC), water-soluble organic carbon (WSOC), water-soluble inorganic ions (WSII), metal elements, organic compounds and stable carbon isotopic composition were measured in the Zhujiang tunnel of Guangzhou, in the PRD region of China in 2013. Emission factors of PM2.5 mass, OC, EC and WSOC were 92.4, 16.7, 16.4 and 1.31 mg vehicle-1 km-1 respectively. Emission factors of WSII were 0.016 (F-) ~ 4.17 (Cl-) mg vehicle-1 km-1, contributing about 9.8% to the PM2.5 emissions. The sum of 27 measured metal elements accounted for 15.2% of PM2.5 emissions. Fe was the most abundant metal element, with an emission factor of 3.91 mg vehicle-1 km-1. Emission factors of organic compounds including n-alkanes, polycyclic aromatic hydrocarbons, hopanes and steranes were 91.9, 5.02, 32.0 and 7.59 μg vehicle-1 km-1, respectively. Stable carbon isotopic composition δ13C value was -25.0‰ on average. An isotopic fractionation of 3.2‰ was found during fuel combustion. Compared to a previous study in Zhujiang tunnel in 2004, emission factors of PM2.5mass, EC, OC, WSII except Cl- and organic compounds decreased by 16.0 ~ 93.4%, which could be attributed to emission control policy from 2004 to 2013. However, emission factors of most of the metal elements increased significantly, which could be partially attributed to the changes in motor oil additives and vehicle conditions. There are no mandatory national standards to limit metal content from vehicle emissions, which should be a concern of the government. A snapshot of the 2013 characteristic emissions of PM2.5 and its constituents from the on-road vehicular fleet in the PRD region retrieved from our study would be helpful for the assessment of past and future implementations of vehicle emission control policy.

Differentiating local and regional sources of Chinese urban air pollution based on the effect of the Spring Festival

NASA Astrophysics Data System (ADS)

Wang, Chuan; Huang, Xiao-Feng; Zhu, Qiao; Cao, Li-Ming; Zhang, Bin; He, Ling-Yan

2017-07-01

The emission of pollutants is extremely reduced during the annual Chinese Spring Festival (SF) in Shenzhen, China. During the SF, traffic flow drops by ˜ 50 % and the industrial plants are almost entirely shut down in Shenzhen. To characterize the variation in ambient air pollutants due to the Spring Festival effect, various gaseous and particulate pollutants were measured in real time in urban Shenzhen over three consecutive winters (2014-2016). The results indicate that the concentrations of NOx, volatile organic compounds (VOCs), black carbon (BC), primary organic aerosols, chloride, and nitrate in submicron aerosols decrease by 50-80 % during SF periods relative to non-Spring Festival periods, regardless of meteorological conditions. This decrease suggests that these pollutants are mostly emitted or secondarily formed from urban local emissions. The concentration variation in species mostly from regional or natural sources, however, is found to be much less, such as for bulk fine particulate matter (PM2. 5). More detailed analysis of the Spring Festival effect reveals an urgent need to reduce emissions of SO2 and VOCs on a regional scale rather than on an urban scale to reduce urban PM2. 5 in Shenzhen, which can also be useful as a reference for other megacities in China.

A new method for modelling roofing materials emissions on the city scale: application for zinc in the City of Créteil (France).

PubMed

Sellami-Kaaniche, Emna; de Gouvello, Bernard; Gromaire, Marie-Christine; Chebbo, Ghassan

2014-04-01

Today, urban runoff is considered as an important source of environmental pollution. Roofing materials, in particular, the metallic ones, are considered as a major source of urban runoff metal contaminations. In the context of the European Water Directive (2000/60 CE), an accurate evaluation of contaminant flows from roofs is thus required on the city scale, and therefore the development of assessment tools is needed. However, on this scale, there is an important diversity of roofing materials. In addition, given the size of a city, a complete census of the materials of the different roofing elements represents a difficult task. Information relating roofing materials and their surfaces on an urban district do not currently exist in urban databases. The objective of this paper is to develop a new method of evaluating annual contaminant flow emissions from the different roofing material elements (e.g., gutter, rooftop) on the city scale. This method is based on using and adapting existing urban databases combined with a statistical approach. Different rules for identifying the materials of the different roofing elements on the city scale have been defined. The methodology is explained through its application to the evaluation of zinc emissions on the scale of the city of Créteil.

Occurrence and sources of natural and anthropogenic lipid tracers in surface soils from arid urban areas of Saudi Arabia.

PubMed

Rushdi, Ahmed I; Al-Mutlaq, Khalid F; El-Mubarak, Aarif H; Al-Saleh, Mohammed A; El-Otaibi, Mubarak T; Ibrahim, Sami M M; Simoneit, Bernd R T

2016-01-01

Soil particles contain a variety of natural and anthropogenic organic components, and in urban areas can be considered as local collectors of pollutants. Surface soil samples were taken from ten urban areas in Riyadh during early winter of 2007. They were extracted with dichloromethane-methanol mixture and the extracts were analyzed by gas chromatography-mass spectrometry. The major compounds were unresolved complex mixture (UCM), plasticizers, n-alkanes, carbohydrates, n-alkanoic acids, hopanes, n-alkanols, and sterols. Vegetation detritus was the major natural source of organic compounds (24.0 ± 15.7%) in samples from areas with less human activities and included n-alkanes, n-alkanoic acids, n-alkanols, sterols and carbohydrates. Vehicular emission products and discarded plastics were the major anthropogenic sources in the soil particles (53.3 ± 21.3% and 22.7 ± 10.7%, respectively). The anthropogenic tracers were UCM, plasticizers, n-alkanes, hopanes and traces of steranes. Vegetation and human activities control the occurrence and distribution of natural and anthropogenic extractable organic matter in this arid urban area. Copyright © 2015 Elsevier Ltd. All rights reserved.

Key factors controlling ozone production in wildfire plumes

NASA Astrophysics Data System (ADS)

Jaffe, D. A.

2017-12-01

Production of ozone in wildfire plumes is complex and highly variable. As a wildfire plume mixes into an urban area, ozone is often, but not always, produced. We have examined multiple factors that can help explain some of this variability. This includes CO/NOy enhancement ratios, photolysis rates, PAN/NOy fraction and degree of NOx oxidation. While fast ozone production is well known, on average, ozone production increases downwind in a plume for several days. Peroxyacetyl nitrate (PAN) is likely a key cause for delayed ozone formation. Recent observations at the Mt. Bachelor Observatory a mountain top observatory relatively remote from nearby anthropogenic influence and in Boise Idaho, an urban setting, show the importance of PAN in wildfire plumes. From these observations we can devise a conceptual model that considers four factors in ozone production: NOx/VOC emission ratio; degree of NOx oxidation; transport time and pathway; and mixing with urban pollutants. Using this conceptual model, we can then devise a lagrangian modeling strategy that can be used to improve our understanding of ozone production in wildfire plumes, both in remote and urban settings.

Climate Change and Developing-Country Cities: Implications For Environmental Health and Equity

PubMed Central

Corvalán, Carlos

2007-01-01

Climate change is an emerging threat to global public health. It is also highly inequitable, as the greatest risks are to the poorest populations, who have contributed least to greenhouse gas (GHG) emissions. The rapid economic development and the concurrent urbanization of poorer countries mean that developing-country cities will be both vulnerable to health hazards from climate change and, simultaneously, an increasing contributor to the problem. We review the specific health vulnerabilities of urban populations in developing countries and highlight the range of large direct health effects of energy policies that are concentrated in urban areas. Common vulnerability factors include coastal location, exposure to the urban heat-island effect, high levels of outdoor and indoor air pollution, high population density, and poor sanitation. There are clear opportunities for simultaneously improving health and cutting GHG emissions most obviously through policies related to transport systems, urban planning, building regulations and household energy supply. These influence some of the largest current global health burdens, including approximately 800,000 annual deaths from ambient urban air pollution, 1.2 million from road-traffic accidents, 1.9 million from physical inactivity, and 1.5 million per year from indoor air pollution. GHG emissions and health protection in developing-country cities are likely to become increasingly prominent in policy development. There is a need for a more active input from the health sector to ensure that development and health policies contribute to a preventive approach to local and global environmental sustainability, urban population health, and health equity. PMID:17393341

Greenhouse gas emissions and the interrelation of urban and forest sectors in reclaiming one hectare of land in the Pacific Northwest.

PubMed

Trlica, Andrew; Brown, Sally

2013-07-02

The interrelation between urban areas and land use options for greenhouse gas mitigation was evaluated by assessing the utility of urban residuals for soil reclamation. Long-term impacts on soil C storage for mine lands restored with urban organic residuals were quantified by sampling historic sites reclaimed both conventionally and with residuals-based amendments. Use of amendments resulted in greater C storage compared to conventional practices for all sites sampled, with increases ranging from 14.2 Mg C ha(-1) in a coalmine in WA to 38.4 Mg C ha(-1) for a copper mine in British Columbia. Expressed as Mg C per Mg amendment, effective C increases ranged from 0.03 to 0.31 Mg C per Mg amendment. Results were applied to three alternative land-use scenarios to model the net GHG balance for a site restored to forest or low-density development. The model included construction of 3.9 243 m(2)-homes, typical of urban sprawl. Emissions for home and road construction and use over a 30-year period resulted in net emissions of 1269 Mg CO2. In contrast, conventional reclamation to forestland or reclamation with 100 Mg of residuals resulted in net GHG reductions of -293 and -475 Mg CO2. Construction of an equivalent number of smaller homes in an urban core coupled with restoration of 1 ha with amendments was close to carbon neutral. These results indicate that targeted use of urban residuals for forest reclamation, coupled with high-density development, can increase GHG mitigation across both sectors.

Assessment of primary and secondary ambient particle trends using satellite aerosol optical depth and ground speciation data in the New England region, United States

PubMed Central

Lee, Hyung Joo; Kang, Choong-Min; Coull, Brent A.; Bell, Michelle L.; Koutrakis, Petros

2014-01-01

The effectiveness of air pollution emission control policies can be evaluated by examining ambient pollutant concentration trends that are observed at a large number of ground monitoring sites over time. In this paper, we used ground monitoring measurements in conjunction with satellite aerosol optical depth (AOD) data to investigate fine particulate matter (PM2.5; particulate matter with aerodynamic diameter ≤2.5 μm) trends and their spatial patterns over a large U.S. region, New England, during 2000–2008. We examined the trends in rural and urban areas to get a better insight about the trends of regional and local source emissions. Decreases in PM2.5 concentrations (μg/m3) were more pronounced in urban areas than in rural ones. In addition, the highest and lowest PM2.5 decreases (μg/m3) were observed for winter and summer, respectively. Together, these findings suggest that primary particle concentrations decreased more relative to secondary ones. This is also supported by the analysis of the speciation data which showed that downward trends of primary pollutants including black carbon were stronger than those of secondary pollutants including sulfate. Furthermore, this study found that ambient primary pollutants decreased at the same rate as their respective source emissions. This was not the case for secondary pollutants which decreased at a slower rate than that of their precursor emissions. This indicates that concentrations of secondary pollutants depend not only on the primary emissions but also on the availability of atmospheric oxidants which might not change during the study period. This novel approach of investigating spatially varying concentration trends, in combination with ground PM2.5 species trends, can be of substantial regulatory importance. PMID:24906074

The role of composition, invasives, and maintenance emissions on urban forest carbon stocks.

PubMed

Horn, Josh; Escobedo, Francisco J; Hinkle, Ross; Hostetler, Mark; Timilsina, Nilesh

2015-02-01

There are few field-based, empirical studies quantifying the effect of invasive trees and palms and maintenance-related carbon emissions on changes in urban forest carbon stocks. We estimated carbon (C) stock changes and tree maintenance-related C emissions in a subtropical urban forest by re-measuring a subsample of residential permanent plots during 2009 and 2011, using regional allometric biomass equations, and surveying residential homeowners near Orlando, FL, USA. The effect of native, non-native, invasive tree species and palms on C stocks and sequestration was also quantified. Findings show 17.8 tC/ha in stocks and 1.2 tC/ha/year of net sequestration. The most important species both by frequency of C stocks and sequestration were Quercus laurifolia Michx. and Quercus virginiana Mill., accounting for 20% of all the trees measured; 60% of carbon stocks and over 75% of net C sequestration. Palms contributed to less than 1% of the total C stocks. Natives comprised two-thirds of the tree population and sequestered 90% of all C, while invasive trees and palms accounted for 5 % of net C sequestration. Overall, invasive and exotic trees had a limited contribution to total C stocks and sequestration. Annual tree-related maintenance C emissions were 0.1% of total gross C sequestration. Plot-level tree, palm, and litter cover were correlated to C stocks and net sequestration. Findings can be used to complement existing urban forest C offset accounting and monitoring protocols and to better understand the role of invasive woody plants on urban ecosystem service provision.

The Role of Composition, Invasives, and Maintenance Emissions on Urban Forest Carbon Stocks

NASA Astrophysics Data System (ADS)

Horn, Josh; Escobedo, Francisco J.; Hinkle, Ross; Hostetler, Mark; Timilsina, Nilesh

2015-02-01

There are few field-based, empirical studies quantifying the effect of invasive trees and palms and maintenance-related carbon emissions on changes in urban forest carbon stocks. We estimated carbon (C) stock changes and tree maintenance-related C emissions in a subtropical urban forest by re-measuring a subsample of residential permanent plots during 2009 and 2011, using regional allometric biomass equations, and surveying residential homeowners near Orlando, FL, USA. The effect of native, non-native, invasive tree species and palms on C stocks and sequestration was also quantified. Findings show 17.8 tC/ha in stocks and 1.2 tC/ha/year of net sequestration. The most important species both by frequency of C stocks and sequestration were Quercus laurifolia Michx. and Quercus virginiana Mill., accounting for 20 % of all the trees measured; 60 % of carbon stocks and over 75 % of net C sequestration. Palms contributed to less than 1 % of the total C stocks. Natives comprised two-thirds of the tree population and sequestered 90 % of all C, while invasive trees and palms accounted for 5 % of net C sequestration. Overall, invasive and exotic trees had a limited contribution to total C stocks and sequestration. Annual tree-related maintenance C emissions were 0.1 % of total gross C sequestration. Plot-level tree, palm, and litter cover were correlated to C stocks and net sequestration. Findings can be used to complement existing urban forest C offset accounting and monitoring protocols and to better understand the role of invasive woody plants on urban ecosystem service provision.

A Comparison of Inventoried and Measured U.S. Urban/Industrial Hg Emission Factors during the NOMADSS Experiment

NASA Astrophysics Data System (ADS)

Ambrose, J. L., II; Gratz, L.; Jaffe, D. A.; Apel, E. C.; Campos, T. L.; Flocke, F. M.; Guenther, A. B.; Hornbrook, R. S.; Karl, T.; Kaser, L.; Knapp, D. J.; Weinheimer, A. J.; Cantrell, C. A.; Mauldin, L.; Yuan, B.

2014-12-01

We performed an airborne survey of some large anthropogenic mercury (Hg) emission sources in the Southeast U.S. during the 2013 Nitrogen, Oxidants, Mercury and Aerosol Distribution, Sources, and Sinks (NOMADSS) experiment. The observations included speciated atmospheric Hg, and tracers of urban/industrial emissions and associated photochemistry (e.g., carbon monoxide, CO; carbon dioxide, CO2; sulfur dioxide, SO2; nitrogen oxides (NOx); volatile organic compounds, VOCs; ozone, O3; hydroxyl radical, HO·; sulfuric acid, H2SO4) and were made from the National Science Foundation's/National Center for Atmospheric Research's C-130 research aircraft. Mercury was measured using the University of Washington's Detector for Oxidized Hg Species. We derived Hg emission factors (EF) for several U.S. urban areas and large industrial point sources, including coal-fired power plants (CFPPs) in Louisiana, Pennsylvania, Texas, and West Virginia. We compared our measured Hg EFs with inventory-based values from two separate Hg emission inventories provided by the U.S. Environmental Protection Agency - the National Emissions Inventory (NEI) and the Toxics Release Inventory (TRI). We also performed an inter-comparison of the inventory-based Hg EFs. For the CFPPs sampled, we find that actual Hg emissions differed from inventoried values by more than a factor of two in some cases. Measured Hg EFs were weakly correlated with values reported in the NEI: m = 0.71; r2 = 0.47 (p = 0.06; n = 8), whereas EFs derived from the TRI were not meaningfully predictive of the measured values: m = -3.3; r2 = 0.61 (p < 0.05; n = 8). Median absolute differences between measured and inventory-based EFs were ≥50%, relative to the inventory values. The median absolute average difference between the Hg EFs reported in the two inventories was approximately 40%. Our results place quantitative constraints on uncertainties associated with the inventoried Hg emissions. Additionally, our results suggest that the current formulation of the Hg emission inventories critically limits our ability to accurately predict the transport and fate of U.S. urban/industrial emissions of Hg to the atmosphere. These findings are broadly relevant to the design and use of emission inventories for industrial hazardous air pollutants.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aden, Nathaniel T.; Zheng, Nina; Fridley, David G.

Urbanization has re-shaped China's economy, society, and energy system. Between 1990 and 2007 China added 290 million new urban residents, bringing the total urbanization rate to 45%. This population adjustment spurred energy demand for construction of new buildings and infrastructure, as well as additional residential use as rural biomass was replaced with urban commercial energy services. Primary energy demand grew at an average annual rate of 10% between 2000 and 2007. Urbanization's effect on energy demand was compounded by the boom in domestic infrastructure investment, and in the export trade following World Trade Organization (WTO) accession in 2001. Industry energymore » consumption was most directly affected by this acceleration. Whereas industry comprised 32% of 2007 U.S. energy use, it accounted for 75% of China's 2007 energy consumption. Five sub-sectors accounted for 78% of China's industry energy use in 2007: iron and steel, energy extraction and processing, chemicals, cement, and non-ferrous metals. Ferrous metals alone accounted for 25% of industry and 18% of total primary energy use. The rapid growth of heavy industry has led China to become by far the world's largest producer of steel, cement, aluminum, and other energy-intensive commodities. However, the energy efficiency of heavy industrial production continues to lag world best practice levels. This study uses scenario analysis to quantify the impact of urbanization and trade on industrial and residential energy consumption from 2000 to 2025. The BAU scenario assumed 67% urbanization, frozen export amounts of heavy industrial products, and achievement of world best practices by 2025. The China Lightens Up (CLU) scenario assumed 55% urbanization, zero net exports of heavy industrial products, and more aggressive efficiency improvements by 2025. The five dominant industry sub-sectors were modeled in both scenarios using a LEAP energy end-use accounting model. The results of this study show that a CLU-style development path would avoid 430 million tonnes coal-equivalent energy use by 2025. More than 60% of these energy savings would come from reduced activity and production levels. In carbon terms, this would amount to more than a billion-tonne reduction of energy-related carbon emissions compared with the BAU scenario in 2025, though the absolute level of emissions rises in both scenarios. Aside from the energy and carbon savings related to CLU scenario development, this study showed impending saturation effects in commercial construction, urban appliance ownership, and fertilizer application. The implication of these findings is that urbanization will have a direct impact on future energy use and emissions - policies to guide urban growth can play a central role in China's efforts to mitigate emissions growth.« less

Building a Multivariable Linear Regression Model of On-road Traffic for Creation of High Resolution Emission Inventories

NASA Astrophysics Data System (ADS)

Powell, James Eckhardt

Emissions inventories are an important tool, often built by governments, and used to manage emissions. To build an inventory of urban CO2 emissions and other fossil fuel combustion products in the urban atmosphere, an inventory of on-road traffic is required. In particular, a high resolution inventory is necessary to capture the local characteristics of transport emissions. These emissions vary widely due to the local nature of the fleet, fuel, and roads. Here we show a new model of ADT for the Portland, OR metropolitan region. The backbone is traffic counter recordings made by the Portland Bureau of Transportation at 7,767 sites over 21 years (1986-2006), augmented with PORTAL (The Portland Regional Transportation Archive Listing) freeway traffic count data. We constructed a regression model to fill in traffic network gaps using GIS data such as road class and population density. An EPA-supplied emissions factor was used to estimate transportation CO2 emissions, which is compared to several other estimates for the city's CO2 footprint.

Design and application of a mobile ground-based observatory for continuous measurements of atmospheric trace-gas and criteria pollutant species

NASA Astrophysics Data System (ADS)

Bush, S. E.; Hopkins, F. M.; Randerson, J. T.; Lai, C.-T.; Ehleringer, J. R.

2015-01-01

Ground-based measurements of atmospheric trace gas species and criteria pollutants are essential for understanding emissions dynamics across space and time. Gas composition in the surface 50 m has the greatest direct impacts on human health as well as ecosystem processes, hence data at this level is necessary for addressing carbon cycle and public health related questions. However, such surface data are generally associated with stationary measurement towers, where spatial representation is limited due to the high cost of establishing and maintaining an extensive network of measurement stations. We describe here a compact mobile laboratory equipped to provide high-precision, high-frequency, continuous, on-road synchronous measurements of CO2, CO, CH4, H2O, NOx, O3, aerosol, meteorological, and geospatial position data. The mobile laboratory has been deployed across the western USA. In addition to describing the vehicle and its capacity, we present data that illustrate the use of the laboratory as a powerful tool for investigating the spatial structure of urban trace gas emissions and criteria pollutants at spatial scales ranging from single streets to whole ecosystem and regional scales. We identify fugitive urban CH4 emissions and assess the magnitude of CH4 emissions from known point sources. We illustrate how such a mobile laboratory can be used to better understand emissions dynamics and quantify emissions ratios associated with trace gas emissions from wildfire incidents. Lastly, we discuss additional mobile laboratory applications in health and urban metabolism.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhu Qin, E-mail: zhuqin@fudan.edu.cn; Peng Xizhe, E-mail: xzpeng@fudan.edu.cn

This study examines the impacts of population size, population structure, and consumption level on carbon emissions in China from 1978 to 2008. To this end, we expanded the stochastic impacts by regression on population, affluence, and technology model and used the ridge regression method, which overcomes the negative influences of multicollinearity among independent variables under acceptable bias. Results reveal that changes in consumption level and population structure were the major impact factors, not changes in population size. Consumption level and carbon emissions were highly correlated. In terms of population structure, urbanization, population age, and household size had distinct effects onmore » carbon emissions. Urbanization increased carbon emissions, while the effect of age acted primarily through the expansion of the labor force and consequent overall economic growth. Shrinking household size increased residential consumption, resulting in higher carbon emissions. Households, rather than individuals, are a more reasonable explanation for the demographic impact on carbon emissions. Potential social policies for low carbon development are also discussed. - Highlights: Black-Right-Pointing-Pointer We examine the impacts of population change on carbon emissions in China. Black-Right-Pointing-Pointer We expand the STIRPAT model by containing population structure factors in the model. Black-Right-Pointing-Pointer The population structure includes age structure, urbanization level, and household size. Black-Right-Pointing-Pointer The ridge regression method is used to estimate the model with multicollinearity. Black-Right-Pointing-Pointer The population structure plays a more important role compared with the population size.« less

Mapping Atmospheric Ammonia Emissions Using a Mobile Quantum Cascade Laser-based Open-path Sensor

NASA Astrophysics Data System (ADS)

Sun, K.; Tao, L.; Miller, D. J.; Khan, M. A.; Zondlo, M. A.

2012-12-01

Ammonia (NH3) is a key precursor to atmospheric fine particulate matter, with strong implications for regional air quality and global climate change. Despite the importance of atmospheric ammonia, its spatial/temporal variation is poorly characterized, and the knowledge of its sources, sinks, and transport is severely limited. Existing measurements suggest that traffic exhaust may provide significant amounts of ammonia in urban areas, which cause greater impacts on particulate matter formation and urban air quality. To capture the spatial and temporal variation of ammonia emissions, a portable, low power sensor with high time resolution is necessary. We have developed a portable open-path ammonia sensor with a detection limit of 0.5 ppbv ammonia for 1 s measurements. The sensor has a power consumption of about 60 W and is capable of running on a car battery continuously for 24 hours. An additional laser has been coupled to the sensor to yield concurrent N2O and CO measurements as tracers for determining various sources. The overall sensor prototype fits on a 60 cm × 20 cm aluminum breadboard. Roadside measurements indicated NH3/CO emission ratios of 4.1±5.4 ppbv/ppmv from a fleet of 320 vehicles, which agree with existing on-ramp measurements. Urban measurements in the Baltimore and Washington, DC metropolitan areas have shown significant ammonia mixing ratios concurrent with carbon monoxide levels from the morning and evening rush hours. On-road measurements of our open-path sensor have also been performed continuously from the Midwest to Princeton, NJ including urban areas such as Pittsburgh, tunnels, and relatively clean conditions. The emission ratios of ammonia against CO and/or CO2 help identify the sources and amounts of both urban and agricultural ammonia emissions. Preliminary data from both spatial mapping, monitoring, and vehicle exhaust measurements suggest that urban ammonia emissions from fossil fuel combustion are significant and may provide an unrecognized source in the atmospheric ammonia budget. Ongoing efforts include spatial mapping of ammonia and other tracers in the New York City and Philadelphia metropolitan areas. Further comparison with TES satellite ammonia retrieval will help to put the measurements into a larger geographical and temporal context.

Anthropogenic and volcanic emission impacts on SO2 dynamics and acid rain profiles. Numerical study using WRF-Chem in a high-resolution modeling

NASA Astrophysics Data System (ADS)

Vela, A. V.; González, C. M.; Ynoue, R.; Rojas, N. Y.; Aristizábal, B. H.; Wahl, M.

2017-12-01

Eulerian 3-D chemistry transport models (CTM) have been widely used for the study of air quality in urban environments, becoming an essential tool for studying the impacts and dynamics of gases and aerosols on air quality. However, their use in Colombia is scarce, especially in medium-sized cities, which are experimenting a fast urban growth, increasing the risk associated with possible air pollution episodes. In the densely populated medium-sized Andean city of Manizales, Colombia - a city located on the western slopes of the central range of the Andes (urban population 368000; 2150 m.a.s.l), there is an influence of the active Nevado del Ruiz volcano, located 28 km to the southwest. This natural source emits daily gas and particle fluxes, which could influence the atmospheric chemistry of the city and neighboring towns. Hence, the zone presents a unique combination of anthropogenic and volcanic sulfur gas emissions, which affects SO2 dynamics in the urban area, influencing also in the formation of acid rain phenomenon in the city. Therefore, studies analyzing the relative contribution of anthropogenic and volcanic emission could contribute with a deep understanding about causes and dynamics of both acid rain phenomenon and ambient SO2 levels in Manizales. This work aimed to analyze the influence of anthropogenic (on-road vehicular and industrial point-sources) and volcanic sulfur emissions in SO2 atmospheric chemistry dynamics, evaluating its possible effects on acid rain profiles. Ambient SO2 levels and day-night rain samples were measured and used to analyze results obtained from the application of the fully-coupled on-line WRF-Chem model. Two high-resolution simulations were performed during two dry and wet one-week periods in 2015. Analysis of SO2 dispersion patterns and comparison with SO2 observations in the urban area were performed for three different scenarios in which natural and anthropogenic emissions were simulated separately. Results suggest that industrial point-source emissions had a higher influence in urban SO2 formation, suggesting also reasons of higher acidity levels during daytime periods, pattern obtained when comparing acid rain day-night profiles from rain samples measurements.

Economics of pollution trading for SO{sub 2} and NOx

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dallas Burtraw; David A. Evans; Alan Krupnick

2005-03-15

For years economists have urged policymakers to use market-based approaches such as cap-and-trade programs or emission taxes to control pollution. The sulphur dioxide (SO{sub 2}) allowance market created by Title IV of the 1990 US Clean Air Act Amendments represents the first real test of the wisdom of economists' advice. Subsequent urban and regional applications of NOx emission allowance trading took shape in the 1990s in the United States, culminating in a second large experiment in emission trading in the eastern United States that began in 2003. This paper provides an overview of the economic rationale for emission trading andmore » a description of the major US programs for SO{sub 2} and nitrogen oxides. These programs are evaluated along measures of performance including cost savings, environmental integrity, and incentives for technological innovation. The authors offer lessons for the design of future programs including, most importantly, those reducing carbon dioxide. 128 refs., 1 fig., 1 tab.« less

CO2 fluxes from a tropical neighborhood: sources and sinks

NASA Astrophysics Data System (ADS)

Velasco, E.; Roth, M.; Tan, S.; Quak, M.; Britter, R.; Norford, L.

2011-12-01

Cities are the main contributors to the CO2 rise in the atmosphere. The CO2 released from the various emission sources is typically quantified by a bottom-up aggregation process that accounts for emission factors and fossil fuel consumption data. This approach does not consider the heterogeneity and variability of the urban emission sources, and error propagation can result in large uncertainties. In this context, direct measurements of CO2 fluxes that include all major and minor anthropogenic and natural sources and sinks from a specific district can be used to evaluate emission inventories. This study reports and compares CO2 fluxes measured directly using the eddy covariance method with emissions estimated by emissions factors and activity data for a residential neighborhood of Singapore, a highly populated and urbanized tropical city. The flux measurements were conducted during one year. No seasonal variability was found as a consequence of the constant climate conditions of tropical places; but a clear diurnal pattern with morning and late afternoon peaks in phase with the rush-hour traffic was observed. The magnitude of the fluxes throughout daylight hours is modulated by the urban vegetation, which is abundant in terms of biomass but not of land-cover (15%). Even though the carbon uptake by vegetation is significant, it does not exceed the anthropogenic emissions and the monitored district is a net CO2 source of 20.3 ton km-2 day-1 on average. The carbon uptake by vegetation is investigated as the difference between the estimated emissions and the measured fluxes during daytime.

AMMONIA EMISSIONS FROM THE EPA'S LIGHT DUTY TEST VEHICLE

EPA Science Inventory

The paper discusses measurements of ammonia (NH3) emissions from EPA's light duty test vehicle while operated on a dynamometer. The vehicle's (1993 Chevrolet equipped with a three-way catalyst) emissions were measured for three transient (urban driving, highway fuel economy, and ...