Impact of the air filtration on indoor particle concentration by using combination filters in offices building

NASA Astrophysics Data System (ADS)

Kabrein, H.; Hariri, A.; Leman, A. M.; Noraini, N. M. R.; Yusof, M. Z. M.; Afandi, A.

2017-09-01

Heating ventilation and air conditioning system (HVAC) is very important for offices building and human health. The combining filter method was used to reduce the air pollution indoor such as that particulate matter and gases pollution that affected in health and productivity. Using particle filters in industrial HVAC systems (factories and manufacturing process) does not enough to remove all the indoor pollution. The main objective of this study is to investigate the impact of combination filters for particle and gases removal efficiency. The combining method is by using two filters (particulate filter pre-filter and carbon filter) to reduce particle matter and gases respectively. The purpose of this study is to use minimum efficiency reporting value (MERV filter) rating 13 and activated carbon filter (ACF) to remove indoor air pollution and controlling the air change rate to enhance the air quality and energy saving. It was concluded that the combination filter showed good removal efficiency of particle up to 90.76% and 89.25% for PM10 and PM2.5 respectively. The pressure drop across the filters was small compared with the high-efficiency filters. The filtration efficiency of combination filters after three months’ was better than efficiency by the new MERV filter alone.

Achieving 'excellent' indoor air quality in commercial offices equipped with air-handling unit--respirable suspended particulate.

PubMed

Lam, K S; Chan, F S; Fung, W Y; Lui, B S S; Lau, L W L

2006-04-01

A study was carried out to investigate the feasibility of achieving ultra low respirable suspended particulates (RSP) in commercial offices without major modification of existing ventilation systems by enhancing the particulates removal efficiency of existing central ventilation systems. Four types of filters which include pre-filters, cartridge filters, bag filters and high efficiency particulates air (HEPA) filters were tested in a commercial building in Causeway Bay. The results show that an RSP objective of <20 microg/m3 could be met by removing RSP from both the return air and outdoor air supply simultaneously. This level of performance is classed as 'excellent' by the Hong Kong Government, Environmental Protection Department. Filters with efficiency that exceed 80% placed both in the return air and outdoor air were sufficient to meet the objective. It is not necessary to install HEPA filters to achieve the 'excellent' class. The outdoor air filter has great influence on the steady state indoor RSP concentration while the effective cleaning rate is governed by the return air filter. Higher efficiency filters increased the static drop but the volume flow of the air fan was not affected significantly. The additional cost incurred was <5% of the existing operation cost. This paper reports a field study of RSP control for an indoor office environment. The results are directly applicable to building service engineering in the design of ventilation systems using air-handling units. Field observations indicated that indoor RSP in an office environment could be suppressed below 20 microg/m3 within 1 h by the simultaneous filtration of outdoor air and return air. Outdoor air filtration has a great influence on the steady state indoor concentration and return air filtration governs the cleaning rate. It is believed that the results of this study could be extended to the cleaning of other indoor pollutants such as volatile organic compounds.

Remotely serviced filter and housing

DOEpatents

Ross, M.J.; Zaladonis, L.A.

1987-07-22

A filter system for a hot cell comprises a housing adapted for input of air or other gas to be filtered, flow of the air through a filter element, and exit of filtered air. The housing is tapered at the top to make it easy to insert a filter cartridge holds the filter element while the air or other gas is passed through the filter element. Captive bolts in trunnion nuts are readily operated by electromechanical manipulators operating power wrenches to secure and release the filter cartridge. The filter cartridge is adapted to make it easy to change a filter element by using a master-slave manipulator at a shielded window station. 6 figs.

Simultaneous removal of formaldehyde and benzene in indoor air with a combination of sorption- and decomposition-type air filters.

PubMed

Sekine, Yoshika; Fukuda, Mitsuru; Takao, Yosuke; Ozano, Takahiro; Sakuramoto, Hikaru; Wang, Kuan Wei

2011-12-01

Urgent measures for indoor air pollution caused by volatile organic compounds are required in urban areas of China. Considering indoor air concentration levels and hazardous properties, formaldehyde and benzene should be given priority for pollution control in China. The authors proposed the use of air-cleaning devices, including stand-alone room air cleaners and in-duct devices. This study aimed to find the best combination of sorption and decomposition filters for the simultaneous removal of formaldehyde and benzene, employing four types of air filter units: an activated charcoal filter (ACF), an ACF impregnated with a trapping agent for acidic gases (ACID), a MnO2 filter (MDF) for oxidative decomposition of formaldehyde at room temperature and a photocatalyst filter (PHOTO) coupled with a parallel beam ultraviolet (UV) irradiation device. The performance of the combined systems under air flow rates of 35-165 m3 h(-1) was evaluated in a test chamber (2 m3) with a constant gas generation system. The experimental results and data analysis using a kinetic approach showed the combined system of ACF, PHOTO and MDF significantly reduced both concentrations of formaldehyde and benzene in air without any unpleasant odours caused by the UV-induced photocatalytic reaction. The system was then evaluated in a full-size laboratory (22 m3). This test proved the practical performance of the system even at full scale, and also suggested that the filters should be arranged in the order of PHOTO/ACF/MDF from upstream to downstream. The proposed system has the potential of being used for improving indoor air quality of houses and buildings in China.

Carbon fiber composite molecular sieve electrically regenerable air filter media

DOEpatents

Wilson, Kirk A.; Burchell, Timothy D.; Judkins, Roddie R.

1998-01-01

An electrically regenerable gas filter system includes a carbon fiber composite molecular sieve (CFCMS) filter medium. After a separate medium-efficiency pre-filter removes particulate from the supply airstream, the CFCMS filter sorbs gaseous air pollutants before the air is recirculated to the space. When saturated, the CFCMS media is regenerated utilizing a low-voltage current that is caused to pass through the filter medium.

Remotely serviced filter and housing

DOEpatents

Ross, Maurice J.; Zaladonis, Larry A.

1988-09-27

A filter system for a hot cell comprises a housing adapted for input of air or other gas to be filtered, flow of the air through a filter element, and exit of filtered air. The housing is tapered at the top to make it easy to insert a filter cartridge using an overhead crane. The filter cartridge holds the filter element while the air or other gas is passed through the filter element. Captive bolts in trunnion nuts are readily operated by electromechanical manipulators operating power wrenches to secure and release the filter cartridge. The filter cartridge is adapted to make it easy to change a filter element by using a master-slave manipulator at a shielded window station.

Effectiveness of photocatalytic filter for removing volatile organic compounds in the heating, ventilation, and air conditioning system.

PubMed

Yu, Kuo-Pin; Lee, Grace Whei-May; Huang, Wei-Ming; Wu, Chih-Cheng; Lou, Chia-ling; Yang, Shinhao

2006-05-01

Nowadays, the heating, ventilation, and air conditioning (HVAC) system has been an important facility for maintaining indoor air quality. However, the primary function of typical HVAC systems is to control the temperature and humidity of the supply air. Most indoor air pollutants, such as volatile organic compounds (VOCs), cannot be removed by typical HVAC systems. Thus, some air handling units for removing VOCs should be added in typical HVAC systems. Among all of the air cleaning techniques used to remove indoor VOCs, photocatalytic oxidation is an attractive alternative technique for indoor air purification and deodorization. The objective of this research is to investigate the VOC removal efficiency of the photocatalytic filter in a HVAC system. Toluene and formaldehyde were chosen as the target pollutants. The experiments were conducted in a stainless steel chamber equipped with a simplified HVAC system. A mechanical filter coated with Degussa P25 titania photocatalyst and two commercial photocatalytic filters were used as the photocatalytic filters in this simplified HVAC system. The total air change rates were controlled at 0.5, 0.75, 1, 1.25, and 1.5 hr(-1), and the relative humidity (RH) was controlled at 30%, 50%, and 70%. The ultraviolet lamp used was a 4-W, ultraviolet-C (central wavelength at 254 nm) strip light bulb. The first-order decay constant of toluene and formaldehyde found in this study ranged from 0.381 to 1.01 hr(-1) under different total air change rates, from 0.34 to 0.433 hr(-1) under different RH, and from 0.381 to 0.433 hr(-1) for different photocatalytic filters.

Room air monitor for radioactive aerosols

DOEpatents

Balmer, David K.; Tyree, William H.

1989-04-11

A housing assembly for use with a room air monitor for simultaneous collection and counting of suspended particles includes a casing containing a combination detector-preamplifier system at one end, a filter system at the other end, and an air flow system consisting of an air inlet formed in the casing between the detector-preamplifier system and the filter system and an air passageway extending from the air inlet through the casing and out the end opposite the detector-preamplifier combination. The filter system collects suspended particles transported directly through the housing by means of the air flow system, and these particles are detected and examined for radioactivity by the detector-pre The U.S. Government has rights in this invention pursuant to Contract No. DE-AC04-76DP03533 between the Department of Energy and Rockwell International Corporation.

40 CFR 90.407 - Engine inlet and exhaust systems.

Code of Federal Regulations, 2012 CFR

2012-07-01

... exhaust emission compliance over the full range of air inlet filter systems and exhaust muffler systems. (b) The air inlet filter system and exhaust muffler system combination used on the test engine must...

40 CFR 90.407 - Engine inlet and exhaust systems.

Code of Federal Regulations, 2013 CFR

2013-07-01

... exhaust emission compliance over the full range of air inlet filter systems and exhaust muffler systems. (b) The air inlet filter system and exhaust muffler system combination used on the test engine must...

40 CFR 90.407 - Engine inlet and exhaust systems.

Code of Federal Regulations, 2014 CFR

2014-07-01

... exhaust emission compliance over the full range of air inlet filter systems and exhaust muffler systems. (b) The air inlet filter system and exhaust muffler system combination used on the test engine must...

40 CFR 90.407 - Engine inlet and exhaust systems.

Code of Federal Regulations, 2011 CFR

2011-07-01

... exhaust emission compliance over the full range of air inlet filter systems and exhaust muffler systems. (b) The air inlet filter system and exhaust muffler system combination used on the test engine must...

40 CFR 90.407 - Engine inlet and exhaust systems.

Code of Federal Regulations, 2010 CFR

2010-07-01

... exhaust emission compliance over the full range of air inlet filter systems and exhaust muffler systems. (b) The air inlet filter system and exhaust muffler system combination used on the test engine must...

ARRANGEMENT FOR REPLACING FILTERS

DOEpatents

Blomgren, R.A.; Bohlin, N.J.C.

1957-08-27

An improved filtered air exhaust system which may be continually operated during the replacement of the filters without the escape of unfiltered air is described. This is accomplished by hermetically sealing the box like filter containers in a rectangular tunnel with neoprene covered sponge rubber sealing rings coated with a silicone impregnated pneumatic grease. The tunnel through which the filters are pushed is normal to the exhaust air duct. A number of unused filters are in line behind the filters in use, and are moved by a hydraulic ram so that a fresh filter is positioned in the air duct. The used filter is pushed into a waiting receptacle and is suitably disposed. This device permits a rapid and safe replacement of a radiation contaminated filter without interruption to the normal flow of exhaust air.

Air filters from HVAC systems as possible source of volatile organic compounds (VOC) - laboratory and field assays

NASA Astrophysics Data System (ADS)

Schleibinger, Hans; Rüden, Henning

The emission of volatile organic compounds (VOC) from air filters of HVAC systems was to be evaluated. In a first study carbonyl compounds (14 aldehydes and two ketones) were measured by reacting them with 2,4-dinitrophenylhydrazine (DNPH). Analysis was done by HPLC and UV detection. In laboratory experiments pieces of used and unused HVAC filters were incubated in test chambers. Filters to be investigated were taken from a filter bank of a large HVAC system in the centre of Berlin. First results show that - among those compounds - formaldehyde and acetone were found in higher concentrations in the test chambers filled with used filters in comparison to those with unused filters. Parallel field measurements were carried out at the prefilter and main filter banks of the two HVAC systems. Here measurements were carried out simultaneously before and after the filters to investigate whether those aldehydes or ketones arise from the filter material on site. Formaldehyde and acetone significantly increased in concentration after the filters of one HVAC system. In parallel experiments microorganisms were proved to be able to survive on air filters. Therefore, a possible source of formaldehyde and acetone might be microbes.

Problems in creation of modern air inlet filters of power gas turbine plants in Russia and methods of their solving

NASA Astrophysics Data System (ADS)

Mikhaylov, V. E.; Khomenok, L. A.; Sherapov, V. V.

2016-08-01

The main problems in creation and operation of modern air inlet paths of gas turbine plants installed as part of combined-cycle plants in Russia are presented. It is noted that design features of air inlet filters shall be formed at the stage of the technical assignment not only considering the requirements of gas turbine plant manufacturer but also climatic conditions, local atmospheric air dustiness, and a number of other factors. The recommendations on completing of filtration system for air inlet filter of power gas turbine plants depending on the facility location are given, specific defects in design and experience in operation of imported air inlet paths are analyzed, and influence of cycle air preparation quality for gas turbine plant on value of operating expenses and cost of repair works is noted. Air treatment equipment of various manufacturers, influence of aerodynamic characteristics on operation of air inlet filters, features of filtration system operation, anti-icing system, weather canopies, and other elements of air inlet paths are considered. It is shown that nonuniformity of air flow velocity fields in clean air chamber has a negative effect on capacity and aerodynamic resistance of air inlet filter. Besides, the necessity in installation of a sufficient number of differential pressure transmitters allowing controlling state of each treatment stage not being limited to one measurement of total differential pressure in the filtration system is noted in the article. According to the results of the analysis trends and methods for modernization of available equipment for air inlet path, the importance of creation and implementation of new technologies for manufacturing of filtering elements on sites of Russia within the limits of import substitution are given, and measures on reliability improvement and energy efficiency for air inlet filter are considered.

Development and testing of a portable wind sensitive directional air sampler

NASA Technical Reports Server (NTRS)

Deyo, J.; Toma, J.; King, R. B.

1975-01-01

A portable wind sensitive directional air sampler was developed as part of an air pollution source identification system. The system is designed to identify sources of air pollution based on the directional collection of field air samples and their analysis for TSP and trace element characteristics. Sources can be identified by analyzing the data on the basis of pattern recognition concepts. The unit, designated Air Scout, receives wind direction signals from an associated wind vane. Air samples are collected on filter slides using a standard high volume air sampler drawing air through a porting arrangement which tracks the wind direction and permits collection of discrete samples. A preset timer controls the length of time each filter is in the sampling position. At the conclusion of the sampling period a new filter is automatically moved into sampling position displacing the previous filter to a storage compartment. Thus the Air Scout may be set up at a field location, loaded with up to 12 filter slides, and left to acquire air samples automatically, according to the wind, at any timer interval desired from 1 to 30 hours.

Workplace Exposure to Titanium Dioxide Nanopowder Released from a Bag Filter System

PubMed Central

Ji, Jun Ho; Kim, Jong Bum; Lee, Gwangjae; Noh, Jung-Hun; Yook, Se-Jin; Cho, So-Hye; Bae, Gwi-Nam

2015-01-01

Many researchers who use laboratory-scale synthesis systems to manufacture nanomaterials could be easily exposed to airborne nanomaterials during the research and development stage. This study used various real-time aerosol detectors to investigate the presence of nanoaerosols in a laboratory used to manufacture titanium dioxide (TiO2). The TiO2 nanopowders were produced via flame synthesis and collected by a bag filter system for subsequent harvesting. Highly concentrated nanopowders were released from the outlet of the bag filter system into the laboratory. The fractional particle collection efficiency of the bag filter system was only 20% at particle diameter of 100 nm, which is much lower than the performance of a high-efficiency particulate air (HEPA) filter. Furthermore, the laboratory hood system was inadequate to fully exhaust the air discharged from the bag filter system. Unbalanced air flow rates between bag filter and laboratory hood systems could result in high exposure to nanopowder in laboratory settings. Finally, we simulated behavior of nanopowders released in the laboratory using computational fluid dynamics (CFD). PMID:26125024

Filters from taxis air conditioning system: A tool to characterize driver's occupational exposure to bioburden?

PubMed

Viegas, Carla; Monteiro, Ana; Dos Santos, Mateus; Faria, Tiago; Caetano, Liliana Aranha; Carolino, Elisabete; Quintal Gomes, Anita; Marchand, Geneviève; Lacombe, Nancy; Viegas, Susana

2018-07-01

Bioburden proliferation in filters from air conditioning systems of taxis represents a possible source of occupational exposure. The aim of this study was to determine the occurrence of fungi and bacteria in filters from the air conditioning system of taxis used for patient transportation and to assess the exposure of drivers to bioburden. Filters from the air conditioning systems of 19 taxis and 28 personal vehicles (used as controls) operating in three Portuguese cities including the capital Lisbon, were collected during the winter season. The occurrence and significance of bioburden detected in the different vehicles are reported and discussed in terms of colony-forming units (CFU) per 1 m 2 of filter area and by the identification of the most frequently detected fungal isolates based on morphology. Azole-resistant mycobiota, fungal biomass, and molecular detection of Aspergillus species/strains were also determined. Bacterial growth was more prevalent in taxis (63.2%) than in personal vehicles (26.3%), whereas fungal growth was more prevalent in personal vehicles (53.6%) than in taxis (21.1-31.6%). Seven different azole-resistant species were identified in this study in 42.1% taxi filters. Levels of fungal biomass were above the detection limit in 63% taxi filters and in 75% personal vehicle filters. No toxigenic species were detected by molecular analysis in the assessed filters. The results obtained show that bioburden proliferation occurs widely in filters from the air conditioning systems of taxis, including the proliferation of azole-resistant fungal species, suggesting that filters should be replaced more frequently. The use of culture based-methods and molecular tools combined enabled an improved risk characterization in this setting. Copyright © 2018 Elsevier Inc. All rights reserved.

78 FR 5773 - Notification of Proposed Production Activity, Generac Power Systems, Inc., Subzone 41J...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-01-28

... assemblies; oil/fuel filters; air/oil separation equipment; air filters/elements; catalytic converters... assemblies; AC line filters; dielectric items of paper/plastic; capacitors; circuit breakers; switching...

Protein-Based Nanofabrics for Multifunctional Air Filtering

NASA Astrophysics Data System (ADS)

Souzandeh, Hamid

With the fast development of economics and population, air pollution is getting worse and becomes a great concern worldwide. The release of chemicals, particulates and biological materials into air can lead to various diseases or discomfort to humans and other living organisms, alongside other serious impacts on the environment. Therefore, improving indoor air quality using various air filters is in critical need because people stay inside buildings most time of the day. However, current air filters using traditional polymers can only remove particles from the polluted air and disposing the huge amount of used air filters can cause serious secondary environmental pollution. Therefore, development of multi-functional air filter materials with environmental friendliness is significant. For this purpose, we developed "green" protein-based multifunctional air-filtering materials. The outstanding performance of the green materials in removal of multiple species of pollutants, including particulate matter, toxic chemicals, and biological hazards, simultaneously, will greatly facilitate the development of the next-generation air-filtration systems. First and foremost, we developed high-performance protein-based nanofabric air-filter mats. It was found that the protein-nanofabrics possess high-efficiency multifunctional air-filtering properties for both particles and various species of chemical gases. Then, the high-performance natural protein-based nanofabrics were promoted both mechanically and functionally by a textured cellulose paper towel. It is interestingly discovered that the textured cellulose paper towel not only can act as a flexible mechanical support, but also a type of airflow regulator which can improve the pollutant-nanofilter interactions. Furthermore, the protein-based nanofabrics were crosslinked in order to enhance the environmental-stability of the filters. It was found that the crosslinked protein-nanofabrics can significantly improve the structure stability against different moisture levels and temperatures, while maintain the multifunctional filtration performance. Moreover, it was demonstrated that the crosslinked protein-nanomaterials also possess antibacterial properties against the selected gram-negative and gram-positive bacteria. This provides a cost-effective solution for advanced "green" nanomaterials with excellent performance in both filtration functions and structure stability under varying environment. This work indicates that protein-based air-filters are promising "green" air-filtering materials for next-generation air-filtration systems.

Concentric Split Flow Filter

NASA Technical Reports Server (NTRS)

Stapleton, Thomas J. (Inventor)

2015-01-01

A concentric split flow filter may be configured to remove odor and/or bacteria from pumped air used to collect urine and fecal waste products. For instance, filter may be designed to effectively fill the volume that was previously considered wasted surrounding the transport tube of a waste management system. The concentric split flow filter may be configured to split the air flow, with substantially half of the air flow to be treated traveling through a first bed of filter media and substantially the other half of the air flow to be treated traveling through the second bed of filter media. This split flow design reduces the air velocity by 50%. In this way, the pressure drop of filter may be reduced by as much as a factor of 4 as compare to the conventional design.

Gross Alpha Beta Radioactivity in Air Filters Measured by Ultra Low Level α/β Counter

NASA Astrophysics Data System (ADS)

Cfarku, Florinda; Bylyku, Elida; Deda, Antoneta; Dhoqina, Polikron; Bakiu, Erjona; Perpunja, Flamur

2010-01-01

Study of radioactivity in air as very important for life is done regularly using different methods in every country. As a result of nuclear reactors, atomic centrals, institutions and laboratories, which use the radioactivity substances in open or closed sources, there are a lot radioactive wastes. Mixing of these wastes after treatment with rivers and lakes waters makes very important control of radioactivity. At the other side nuclear and radiological accidents are another source of the contamination of air and water. Due to their radio toxicity, especially those of Sr90, Pu239, etc. a contamination hazard for human begins exist even at low concentration levels. Measurements of radioactivity in air have been performed in many parts of the world mostly for assessment of the doses and risk resulting from consuming air. In this study we present the results of international comparison organized by IAEA Vienna, Austria for the air filters spiked with unknown Alpha and Beta Activity. For the calibration of system we used the same filters spiked: a) with Pu-239 as alpha source; b) Sr-90 as beta source and also the blank filter. The measurements of air filter samples after calibration of the system are done with Ultra Low Level α/β Counter (MPC 9604) Protean Instrument Corporation. The high sensitivity of the system for the determination of the Gross Alpha and Beta activity makes sure detection of low values activity of air filters. Our laboratory results are: Aα = (0.19±0.01) Bq/filter and Aα (IAEA) = (0.17±0.009) Bq/filter; Aβ = (0.33±0.009) Bq/filter and Aβ (IAEA) = (0.29±0.01) Bq/filter. As it seems our results are in good agreement with reference values given by IAEA (International Atomic Energy Agency).

Laboratory and on-road evaluations of cabin air filters using number and surface area concentration monitors.

PubMed

Qi, Chaolong; Stanley, Nick; Pui, David Y H; Kuehn, Thomas H

2008-06-01

An automotive cabin air filter's effectiveness for removing airborne particles was determined both in a laboratory wind tunnel and in vehicle on-road tests. The most penetrating particle size for the test filter was approximately 350 nm, where the filtration efficiency was 22.9 and 17.4% at medium and high fan speeds, respectively. The filtration efficiency increased for smaller particles and was 43.9% for 100 nm and 72.0% for 20 nm particles at a medium fan speed. We determined the reduction in passenger exposure to particles while driving in freeway traffic caused by a vehicle ventilation system with a cabin air filter installed. Both particle number and surface area concentration measurements were made inside the cabin and in the surrounding air. At medium fan speed, the number and surface area concentration-based exposure reductions were 65.6 +/- 6.0% and 60.6 +/- 9.4%, respectively. To distinguish the exposure reduction contribution from the filter alone and the remainder of the ventilation system, we also performed tests with and without the filter in place using the surface area monitors. The ventilation system operating in the recirculation mode with the cabin air filter installed provided the maximum protection, reducing the cabin particle concentration exponentially over time and usually taking only 3 min to reach 10 microm2/cm3 (a typical office air condition) under medium fan speed.

21 CFR 113.40 - Equipment and procedures.

Code of Federal Regulations, 2011 CFR

2011-04-01

... ensure a supply of clean, dry air. (3) Pressure gages. Each retort should be equipped with a pressure... should have adequate filter systems to ensure a supply of clean, dry air. (3) Pressure gages. (i) Each... controllers should have adequate filter systems to ensure a supply of clean, dry air. (3) Pressure gages. Each...

21 CFR 113.40 - Equipment and procedures.

Code of Federal Regulations, 2014 CFR

2014-04-01

... have adequate filter systems to ensure a supply of clean, dry air. A steam controller activated by the... ensure a supply of clean, dry air. (5) Steam introduction. Steam shall be distributed in the bottom of... temperature controllers should have adequate filter systems to ensure a supply of clean, dry air. (5) Bleeders...

21 CFR 113.40 - Equipment and procedures.

Code of Federal Regulations, 2013 CFR

2013-04-01

... have adequate filter systems to ensure a supply of clean, dry air. A steam controller activated by the... ensure a supply of clean, dry air. (5) Steam introduction. Steam shall be distributed in the bottom of... temperature controllers should have adequate filter systems to ensure a supply of clean, dry air. (5) Bleeders...

21 CFR 113.40 - Equipment and procedures.

Code of Federal Regulations, 2012 CFR

2012-04-01

... have adequate filter systems to ensure a supply of clean, dry air. A steam controller activated by the... ensure a supply of clean, dry air. (5) Steam introduction. Steam shall be distributed in the bottom of... temperature controllers should have adequate filter systems to ensure a supply of clean, dry air. (5) Bleeders...

System and Apparatus for Filtering Particles

NASA Technical Reports Server (NTRS)

Agui, Juan H. (Inventor); Vijayakumar, Rajagopal (Inventor)

2015-01-01

A modular pre-filtration apparatus may be beneficial to extend the life of a filter. The apparatus may include an impactor that can collect a first set of particles in the air, and a scroll filter that can collect a second set of particles in the air. A filter may follow the pre-filtration apparatus, thus causing the life of the filter to be increased.

Aircraft Recirculation Filter for Air-Quality and Incident Assessment

PubMed Central

Eckels, Steven J.; Jones, Byron; Mann, Garrett; Mohan, Krishnan R.; Weisel, Clifford P.

2015-01-01

The current research examines the possibility of using recirculation filters from aircraft to document the nature of air-quality incidents on aircraft. These filters are highly effective at collecting solid and liquid particulates. Identification of engine oil contaminants arriving through the bleed air system on the filter was chosen as the initial focus. A two-step study was undertaken. First, a compressor/bleed air simulator was developed to simulate an engine oil leak, and samples were analyzed with gas chromatograph-mass spectrometry. These samples provided a concrete link between tricresyl phosphates and a homologous series of synthetic pentaerythritol esters from oil and contaminants found on the sample paper. The second step was to test 184 used aircraft filters with the same gas chromatograph-mass spectrometry system; of that total, 107 were standard filters, and 77 were nonstandard. Four of the standard filters had both markers for oil, with the homologous series synthetic pentaerythritol esters being the less common marker. It was also found that 90% of the filters had some detectable level of tricresyl phosphates. Of the 77 nonstandard filters, 30 had both markers for oil, a significantly higher percent than the standard filters. PMID:25641977

Aircraft Recirculation Filter for Air-Quality and Incident Assessment.

PubMed

Eckels, Steven J; Jones, Byron; Mann, Garrett; Mohan, Krishnan R; Weisel, Clifford P

The current research examines the possibility of using recirculation filters from aircraft to document the nature of air-quality incidents on aircraft. These filters are highly effective at collecting solid and liquid particulates. Identification of engine oil contaminants arriving through the bleed air system on the filter was chosen as the initial focus. A two-step study was undertaken. First, a compressor/bleed air simulator was developed to simulate an engine oil leak, and samples were analyzed with gas chromatograph-mass spectrometry. These samples provided a concrete link between tricresyl phosphates and a homologous series of synthetic pentaerythritol esters from oil and contaminants found on the sample paper. The second step was to test 184 used aircraft filters with the same gas chromatograph-mass spectrometry system; of that total, 107 were standard filters, and 77 were nonstandard. Four of the standard filters had both markers for oil, with the homologous series synthetic pentaerythritol esters being the less common marker. It was also found that 90% of the filters had some detectable level of tricresyl phosphates. Of the 77 nonstandard filters, 30 had both markers for oil, a significantly higher percent than the standard filters.

Hemodialysis dialyzers contribute to contamination of air microemboli that bypass the alarm system in the air trap.

PubMed

Stegmayr, C; Jonsson, P; Forsberg, U; Stegmayr, B

2008-04-01

Previous studies have shown that micrometer-sized air bubbles are introduced into the patient during hemodialysis. The aim of this study was to investigate, in vitro, the influence of dialysis filters on the generation of air bubbles. Three different kind of dialyzers were tested: one high-flux FX80 dry filter (Fresenius Medical Care AG&Co. KGaA, Bad Homburg, Germany), one low-flux F8HPS dry filter (Fresenius Medical Care AG&Co. KGaA, Bad Homburg, Germany) and a wet-stored APS-18u filter (Asahi Kasei Medical, Tokyo, Japan). The F8HPS was tested with pump flow ranging between 100 to 400 ml/min. The three filters were compared using a constant pump flow of 300 ml/min. Measurements were performed using an ultrasound Doppler instrument. In 90% of the series, bubbles were measured after the outlet line of the air trap without triggering an alarm. There were significantly more bubbles downstream than upstream of the filters F8HPS and FX80, while there was a significant reduction using the APS-18u. There was no reduction in the number of bubbles after passage through the air trap versus before the air trap (after the dialyzer). Increased priming volume reduced the extent of bubbles in the system. Data indicate that the air trap does not prevent air microemboli from entering the venous outlet part of the dialysis tubing (entry to the patient). More extended priming of the dialysis circuit may reduce the extent of microemboli that originate from dialysis filters. A wet filter may be favorable instead of dry-steam sterilized filters.

Antimicrobial nanoparticle-coated electrostatic air filter with high filtration efficiency and low pressure drop.

PubMed

Sim, Kyoung Mi; Park, Hyun-Seol; Bae, Gwi-Nam; Jung, Jae Hee

2015-11-15

In this study, we demonstrated an antimicrobial nanoparticle-coated electrostatic (ES) air filter. Antimicrobial natural-product Sophora flavescens nanoparticles were produced using an aerosol process, and were continuously deposited onto the surface of air filter media. For the electrostatic activation of the filter medium, a corona discharge electrification system was used before and after antimicrobial treatment of the filter. In the antimicrobial treatment process, the deposition efficiency of S. flavescens nanoparticles on the ES filter was ~12% higher than that on the pristine (Non-ES) filter. In the evaluation of filtration performance using test particles (a nanosized KCl aerosol and submicron-sized Staphylococcus epidermidis bioaerosol), the ES filter showed better filtration efficiency than the Non-ES filter. However, antimicrobial treatment with S. flavescens nanoparticles affected the filtration efficiency of the filter differently depending on the size of the test particles. While the filtration efficiency of the KCl nanoparticles was reduced on the ES filter after the antimicrobial treatment, the filtration efficiency was improved after the recharging process. In summary, we prepared an antimicrobial ES air filter with >99% antimicrobial activity, ~92.5% filtration efficiency (for a 300-nm KCl aerosol), and a ~0.8 mmAq pressure drop (at 13 cm/s). This study provides valuable information for the development of a hybrid air purification system that can serve various functions and be used in an indoor environment. Copyright © 2015 Elsevier B.V. All rights reserved.

Indoor-outdoor relationships of PM2.5 in four residential dwellings in winter in the Yangtze River Delta, China.

PubMed

Wang, Fang; Meng, Dan; Li, Xiuwei; Tan, Junjie

2016-08-01

Indoor and outdoor air PM2.5 concentrations in four residential dwellings characterized with different building envelope air tightness levels and HVAC-filter configurations in Yangtze River Delta (YRD) were measured during winter periods in 2014-2015. Steady-state models for indoor PM2.5 were developed for each of the tested dwellings, based on mass balance equation. The indoor air PM2.5 concentrations in the four tested apartments were significantly different. The lowest geometric mean values of indoor air PM2.5 concentrations, I/O ratios, and infiltration factor were observed in D3 with high air tightness and without HVAC-filter system (26.0 μg/m(3), 0.197, and 0.167, respectively), while the highest geometric mean values of indoor air PM2.5 concentrations, I/O ratios, and infiltration factor were observed in D1 (64.9 μg/m(3), 0.876, and 0.867, respectively). For apartment D1 with normal air tightness and without any HVAC-filter system, indoor air PM2.5 concentrations were significantly correlated with outdoor PM2.5 concentrations, especially in severe ambient pollution days, when closed windows can only play a very weak role on the decline of indoor PM2.5 concentrations. With the enhancement of building air tightness, the indoor air PM2.5 concentrations can be decreased effectively and don't vary as much in response to fluctuations in ambient concentrations. For buildings with normal air tightness, the use of HVAC-filter combinations will decrease the indoor PM2.5 significantly. However, for buildings with enhanced air tightness, the only use of fresh makeup air supply system with filter may increase the indoor PM2.5 concentrations. The improvement of filter efficiency for both fresh makeup air and indoor recirculated air are very important. However, purifiers for indoor recirculated air were highly recommended for all buildings. Copyright © 2016 Elsevier Ltd. All rights reserved.

Improving indoor air quality and thermal comfort in office building by using combination filters

NASA Astrophysics Data System (ADS)

Kabrein, H.; Yusof, M. Z. M.; Hariri, A.; Leman, A. M.; Afandi, A.

2017-09-01

Poor indoor air quality and thermal comfort condition in the workspace affected the occupants’ health and work productivity, especially when adapting the recirculation of air in heating ventilation and air-conditioning (HVAC) system. The recirculation of air was implemented in this study by mixing the circulated returned indoor air with the outdoor fresh air. The aims of this study are to assess the indoor thermal comfort and indoor air quality (IAQ) in the office buildings, equipped with combination filters. The air filtration technique consisting minimum efficiency reporting value (MERV) filter and activated carbon fiber (ACF) filter, located before the fan coil units. The findings of the study show that the technique of mixing recirculation air with the fresh air through the combination filters met the recommended thermal comfort condition in the workspace. Furthermore, the result of the post-occupancy evaluation (POE) and the environmental measurements comply with the ASHRAE 55 standard. In addition, the level of CO2 concentration continued to decrease during the period of the measurement.

Air filtration systems and restrictive access conditions improve indoor air quality in clinical units: Penicillium as a general indicator of hospital indoor fungal levels.

PubMed

Araujo, Ricardo; Cabral, João Paulo; Rodrigues, Acácio Gonçalves

2008-03-01

High-efficiency particulate air (HEPA) filters do not completely prevent nosocomial fungal infections. The first aim of this study was to evaluate the impact of different filters and access conditions upon airborne fungi in hospital facilities. Additionally, this study identified fungal indicators of indoor air concentrations. Eighteen rooms and wards equipped with different air filter systems, and access conditions were sampled weekly, during 16 weeks. Tap water samples were simultaneously collected. The overall mean concentration of atmospheric fungi for all wards was 100 colony forming units/m(3). We found a direct proportionality between the levels of the different fungi in the studied atmospheres. Wards with HEPA filters at positive air flow yielded lower fungal levels. Also, the existence of an anteroom and the use of protective clothes were associated to the lowest fungal levels. Principal component analysis showed that penicillia afforded the best separation between wards' air fungal levels. Fungal strains were rarely recovered from tap water samples. In addition to air filtration systems, some access conditions to hospital units, like presence of anteroom and use of protective clothes, may prevent high fungal air load. Penicillia can be used as a general indicator of indoor air fungal levels at Hospital S. João.

Emergency sacrificial sealing method in filters, equipment, or systems

DOEpatents

Brown, Erik P

2014-09-30

A system seals a filter or equipment component to a base and will continue to seal the filter or equipment component to the base in the event of hot air or fire. The system includes a first sealing material between the filter or equipment component and the base; and a second sealing material between the filter or equipment component and the base and proximate the first sealing material. The first sealing material and the second seal material are positioned relative to each other and relative to the filter or equipment component and the base to seal the filter or equipment component to the base and upon the event of fire the second sealing material will be activated and expand to continue to seal the filter or equipment component to the base in the event of hot air or fire.

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

Fisk, William J.; Destaillats, H.; Apte, M.G.

Heating, ventilating, and cooling classrooms in California consume substantial electrical energy. Indoor air quality (IAQ) in classrooms affects studenthealth and performance. In addition to airborne pollutants that are emitted directly by indoor sources and those generated outdoors, secondary pollutants can be formed indoors by chemical reaction of ozone with other chemicals and materials. Filters are used in nearly all classroom heating, ventilation and air?conditioning (HVAC) systems to maintain energy-efficient HVAC performance and improve indoor air quality; however, recent evidence indicates that ozone reactions with filters may, in fact, be a source of secondary pollutants. This project quantitatively evaluated ozone depositionmore » in HVAC filters and byproduct formation, and provided a preliminary assessment of the extent towhich filter systems are degrading indoor air quality. The preliminary information obtained will contribute to the design of subsequent research efforts and the identification of energy efficient solutions that improve indoor air quality in classrooms and the health and performance of students.« less

Air-mass flux measurement system using Doppler-shifted filtered Rayleigh scattering

NASA Technical Reports Server (NTRS)

Shirley, John A.; Winter, Michael

1993-01-01

An optical system has been investigated to measure mass flux distributions in the inlet of a high speed air-breathing propulsion system. Rayleigh scattered light from air is proportional to the number density of molecules and hence can be used to ascertain the gas density in a calibrated system. Velocity field measurements are achieved by spectrally filtering the elastically-scattered Doppler-shifted light with an absorbing molecular filter. A novel anamorphic optical collection system is used which allows optical rays from different scattering angles, that have different Doppler shifts, to be recorded separately. This is shown to obviate the need to tune the laser through the absorption to determine velocities, while retaining the ability to make spatially-resolved measurements along a line. By properly selecting the laser tuning and filter parameters, simultaneous density measurements can be made. These properties are discussed in the paper and experiments demonstrating the velocimetry capability are described.

The impact of particle filtration on indoor air quality in a classroom near a highway.

PubMed

van der Zee, S C; Strak, M; Dijkema, M B A; Brunekreef, B; Janssen, N A H

2017-03-01

A pilot study was performed to investigate whether the application of a new mechanical ventilation system with a fine F8 (MERV14) filter could improve indoor air quality in a high school near the Amsterdam ring road. PM10, PM2.5, and black carbon (BC) concentrations were measured continuously inside an occupied intervention classroom and outside the school during three sampling periods in the winter of 2013/2014. Initially, 3 weeks of baseline measurements were performed, with the existing ventilation system and normal ventilation habits. Next, an intervention study was performed. A new ventilation system was installed in the classroom, and measurements were performed during 8 school weeks, in alternating 2-week periods with and without the filter in the ventilation system under otherwise identical ventilation conditions. Indoor/outdoor ratios measured during the weeks with filter were compared with those measured without filter to evaluate the ability of the F8 filter to improve indoor air quality. During teaching hours, the filter reduced BC exposure by, on average, 36%. For PM10 and PM2.5, a reduction of 34% and 30% was found, respectively. This implies that application of a fine filter can reduce the exposure of schoolchildren to traffic exhaust at hot spot locations by about one-third. © 2016 The Authors. Indoor Air published by John Wiley & Sons Ltd.

40 CFR 1068.261 - What provisions apply for selling or shipping certified engines that are not yet in the certified...

Code of Federal Regulations, 2010 CFR

2010-07-01

... without air filters or other portions of the air intake system that are specifically identified by part... appropriate aftertreatment device and/or air filter, but without completing the assembly with all the... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS GENERAL...

40 CFR 1068.261 - What provisions apply for selling or shipping certified engines that are not yet in the certified...

Code of Federal Regulations, 2011 CFR

2011-07-01

... without air filters or other portions of the air intake system that are specifically identified by part... appropriate aftertreatment device and/or air filter, but without completing the assembly with all the... Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS GENERAL...

Isokinetic air sampler

DOEpatents

Sehmel, George A.

1979-01-01

An isokinetic air sampler includes a filter, a holder for the filter, an air pump for drawing air through the filter at a fixed, predetermined rate, an inlet assembly for the sampler having an inlet opening therein of a size such that isokinetic air sampling is obtained at a particular wind speed, a closure for the inlet opening and means for simultaneously opening the closure and turning on the air pump when the wind speed is such that isokinetic air sampling is obtained. A system incorporating a plurality of such samplers provided with air pumps set to draw air through the filter at the same fixed, predetermined rate and having different inlet opening sizes for use at different wind speeds is included within the ambit of the present invention as is a method of sampling air to measure airborne concentrations of particulate pollutants as a function of wind speed.

Cleaner Air for Home and Office

NASA Technical Reports Server (NTRS)

1989-01-01

Increased insulation has led to higher concentrations in homes and offices of toxic chemicals caused by emissions from synthetic building components. Recent NASA research regarding future interplanetary manned spacecraft has shown that certain plants can absorb gasses, reducing indoor air pollution. After working with water purifying water hyacinths, Dr. B. C. Wolverton at NSTL developed a carbon/plant filter system to remove chemicals, smoke, etc. Two companies have commercialized the system. Bio-safe provides plants, a bed of activated carbon and an air pump installed near the plant's roots. Pollutants are trapped by the charcoal and either digested by the roots or broken down by microorganisms. Purified air is then directed back into the room. Applied Indoor Resource Company markets Bio-Pure, which includes plants on a layer of patented soil medium with activated carbon. Legumes and mosses filter the air; a blower moves air through the filtering system for cleansing by microorganisms. Research at NSTL continues, and the system may eventually be enlarged.

Aspergillus prevalence in air conditioning filters from vehicles: taxis for patient transportation, forklifts, and personal vehicles.

PubMed

Viegas, Carla; Moreira, Ricardo; Faria, Tiago; Caetano, Liliana Aranha; Carolino, Elisabete; Gomes, Anita Quintal; Viegas, Susana

2018-05-04

The frequency and importance of Aspergillus infections is increasing worldwide. This study aimed to assess the occupational exposure of forklifts and taxi drivers to Aspergillus spp. Nineteen filters from air conditioning system of taxis, 17 from forklifts and 37 from personal vehicles were assessed. Filters extract were streaked onto MEA, DG18 and in azole-supplemented media. Real-time quantitative PCR amplification of selected Aspergillus species-complex was also performed. Forklifts filter samples presented higher median values. Aspergillus section Nigri was the most observed in forklifts filters in MEA (28.2%) and in azole-supplemented media. DNA from Aspergillus sections Fumigati and Versicolores was successfully amplified by qPCR. This study enlightens the added value of using filters from the air conditioning system to assess Aspergillus spp. occupational exposure. Aspergillus azole resistance screening should be included in future occupational exposure assessments.

Emergency sacrificial sealing method in filters, equipment, or systems

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

Brown, Erik P.

A system seals a filter or equipment component to abase and will continue to seal the filter or equipment component to the base in the event of hot air or fire. The system includes a first sealing material between the filter or equipment component and the base; and a second sealing material between the filter or equipment component and the base and proximate the first sealing material. The first sealing material and the second seal material are positioned relative to each other and relative to the filter or equipment component and the base to seal the filter or equipment componentmore » to the base and upon the event of fire the second sealing material will be activated and expand to continue to seal the filter or equipment component to the base in the event of hot air or fire.« less

Whole house particle removal and clean air delivery rates for in-duct and portable ventilation systems.

PubMed

Macintosh, David L; Myatt, Theodore A; Ludwig, Jerry F; Baker, Brian J; Suh, Helen H; Spengler, John D

2008-11-01

A novel method for determining whole house particle removal and clean air delivery rates attributable to central and portable ventilation/air cleaning systems is described. The method is used to characterize total and air-cleaner-specific particle removal rates during operation of four in-duct air cleaners and two portable air-cleaning devices in a fully instrumented test home. Operation of in-duct and portable air cleaners typically increased particle removal rates over the baseline rates determined in the absence of operating a central fan or an indoor air cleaner. Removal rates of 0.3- to 0.5-microm particles ranged from 1.5 hr(-1) during operation of an in-duct, 5-in. pleated media filter to 7.2 hr(-1) for an in-duct electrostatic air cleaner in comparison to a baseline rate of 0 hr(-1) when the air handler was operating without a filter. Removal rates for total particulate matter less than 2.5 microm in aerodynamic diameter (PM2.5) mass concentrations were 0.5 hr(-1) under baseline conditions, 0.5 hr(-1) during operation of three portable ionic air cleaners, 1 hr(-1) for an in-duct 1-in. media filter, 2.4 hr(-1) for a single high-efficiency particle arrestance (HEPA) portable air cleaner, 4.6 hr(-1) for an in-duct 5-in. media filter, 4.7 hr(-1) during operation of five portable HEPA filters, 6.1 hr(-1) for a conventional in-duct electronic air cleaner, and 7.5 hr(-1) for a high efficiency in-duct electrostatic air cleaner. Corresponding whole house clean air delivery rates for PM2.5 attributable to the air cleaner independent of losses within the central ventilation system ranged from 2 m3/min for the conventional media filter to 32 m3/min for the high efficiency in-duct electrostatic device. Except for the portable ionic air cleaner, the devices considered here increased particle removal indoors over baseline deposition rates.

Stay away from asthma triggers

MedlinePlus

... cleaner with a HEPA (high-efficiency particulate arrestor) filter. Replace wall-to-wall carpet with wood or ... a central air conditioning system, use a HEPA filter to remove pet allergens from indoor air. Use ...

Cabin air filtration: helping to protect occupants from infectious diseases.

PubMed

Bull, Karen

2008-05-01

Presentation made at the Aviation Health Conference, London, November 2006. In modern aircraft, the air in the cabin is provided by the environmental control system (ECS) and consists of approximately 50% outside air (engine 'bleed air') mixed with approximately 50% filtered, recirculated air. This paper describes how modern aircraft cabin air filters are effective at removing airborne particulate contamination (such as bacteria and viruses) from the recirculated air system. It also describes one of the technological solutions that is currently available to treat any odours or volatile organic compounds (VOCs) that may be present in the aircraft ECS.

Instituting a filtration/pressurization system to reduce dust concentrations in a control room at a mineral processing plant

PubMed Central

Noll, J.; Cecala, A.; Hummer, J.

2016-01-01

The National Institute for Occupational Safety and Health has observed that many control rooms and operator compartments in the U.S. mining industry do not have filtration systems capable of maintaining low dust concentrations in these areas. In this study at a mineral processing plant, to reduce respirable dust concentrations in a control room that had no cleaning system for intake air, a filtration and pressurization system originally designed for enclosed cabs was modified and installed. This system was composed of two filtering units: one to filter outside air and one to filter and recirculate the air inside the control room. Eighty-seven percent of submicrometer particles were reduced by the system under static conditions. This means that greater than 87 percent of respirable dust particles should be reduced as the particle-size distribution of respirable dust particles is greater than that of submicrometer particles, and filtration systems usually are more efficient in capturing the larger particles. A positive pressure near 0.02 inches of water gauge was produced, which is an important component of an effective system and minimizes the entry of particles, such as dust, into the room. The intake airflow was around 118 cfm, greater than the airflow suggested by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) for acceptable indoor air quality. After one year, the loading of the filter caused the airflow to decrease to 80 cfm, which still produces acceptable indoor air quality. Due to the loading of the filters, the reduction efficiency for submicrometer particles under static conditions increased to 94 percent from 87 percent. PMID:26834293

Numerical study of canister filters with alternatives filter cap configurations

NASA Astrophysics Data System (ADS)

Mohammed, A. N.; Daud, A. R.; Abdullah, K.; Seri, S. M.; Razali, M. A.; Hushim, M. F.; Khalid, A.

2017-09-01

Air filtration system and filter play an important role in getting a good quality air into turbo machinery such as gas turbine. The filtration system and filter has improved the quality of air and protect the gas turbine part from contaminants which could bring damage. During separation of contaminants from the air, pressure drop cannot be avoided but it can be minimized thus helps to reduce the intake losses of the engine [1]. This study is focused on the configuration of the filter in order to obtain the minimal pressure drop along the filter. The configuration used is the basic filter geometry provided by Salutary Avenue Manufacturing Sdn Bhd. and two modified canister filter cap which is designed based on the basic filter model. The geometries of the filter are generated by using SOLIDWORKS software and Computational Fluid Dynamics (CFD) software is used to analyse and simulates the flow through the filter. In this study, the parameters of the inlet velocity are 0.032 m/s, 0.063 m/s, 0.094 m/s and 0.126 m/s. The total pressure drop produce by basic, modified filter 1 and 2 is 292.3 Pa, 251.11 Pa and 274.7 Pa. The pressure drop reduction for the modified filter 1 is 41.19 Pa and 14.1% lower compared to basic filter and the pressure drop reduction for modified filter 2 is 17.6 Pa and 6.02% lower compared to the basic filter. The pressure drops for the basic filter are slightly different with the Salutary Avenue filter due to limited data and experiment details. CFD software are very reliable in running a simulation rather than produces the prototypes and conduct the experiment thus reducing overall time and cost in this study.

Measuring Concentrations of Particulate 140La in the Air

DOE PAGES

Okada, Colin E.; Kernan, Warnick J.; Keillor, Martin E.; ...

2016-05-01

Air sampling systems were deployed to measure the concentration of radioactive material in the air during the Full-Scale Radiological Dispersal Device experiments. The air samplers were positioned 100-600 meters downwind of the release point. The filters were collected immediately and analyzed in the field. Quantities for total activity collected on the air filters are reported along with additional information to compute the average or integrated air concentrations.

76 FR 74708 - National Emission Standards for Hazardous Air Pollutants for Source Categories

Federal Register 2010, 2011, 2012, 2013, 2014

2011-12-01

... as follows: Bag leak detection system means a monitoring device for a fabric filter that identifies an increase in particulate matter emissions resulting from a broken filter bag or other malfunction... thermoset a binder on the mineral wool fiber used to make bonded products. Fabric filter means an air...

Electrospun Magnetic Nanoparticle-Decorated Nanofiber Filter and Its Applications to High-Efficiency Air Filtration.

PubMed

Kim, Juyoung; Chan Hong, Seung; Bae, Gwi Nam; Jung, Jae Hee

2017-10-17

Filtration technology has been widely studied due to concerns about exposure to airborne dust, including metal oxide nanoparticles, which cause serious health problems. The aim of these studies has been to develop mechanisms for the continuous and efficient removal of metal oxide dusts. In this study, we introduce a novel air filtration system based on the magnetic attraction force. The filtration system is composed of a magnetic nanoparticle (MNP)-decorated nanofiber (MNP-NF) filter. Using a simple electrospinning system, we fabricated continuous and smooth electrospun nanofibers with evenly distributed Fe 3 O 4 MNPs. Our electrospun MNP-NF filter exhibited high particle collection efficiency (∼97% at 300 nm particle size) compared to the control filter (w/o MNPs, ∼ 68%), with a ∼ 64% lower pressure drop (∼17 Pa) than the control filter (∼27 Pa). Finally, the filter quality factors of the MNP-NF filter were 4.7 and 11.9 times larger than those of the control filter and the conventional high-efficiency particulate air filters (>99% and ∼269 Pa), respectively. Furthermore, we successfully performed a field test of our MNP-NF filter using dust from a subway station tunnel. This work suggests that our novel MNP-NF filter can be used to facilitate effective protection against hazardous metal oxide dust in real environments.

Combined air and water pollution control system

NASA Technical Reports Server (NTRS)

Wolverton, Billy C. (Inventor); Jarrell, Lamont (Inventor)

1990-01-01

A bioaquatic air pollution control system for controlling both water and atmospheric pollution is disclosed. The pollution control system includes an exhaust for directing polluted gases out of a furnace and a fluid circulating system which circulates fluid, such as waste water, from a source, past the furnace where the fluid flow entrains the pollutants from the furnace. The combined fluid and pollutants are then directed through a rock/plant/microbial filtering system. A suction pump pumps the treated waste water from the filter system past the exhaust to again entrain more pollutants from the furnace where they are combined with the fluid (waste water) and directed to the filter system.

The effect of ambient ozone and humidity on the performance of nylon and Teflon filters used in ambient air monitoring filter-pack systems

Treesearch

PE Padgett

2010-01-01

Nylon and Teflon filter media are frequently used for monitoring ambient air pollutants. These media are subject to many environmental factors that may influence adsorption and retention of particulate and gaseous nitrogenous pollutants. This study evaluated the effects of ozone and humidity on the efficacy of nylon and Teflon filters used in the US dry deposition...

Optical air data systems and methods

NASA Technical Reports Server (NTRS)

Caldwell, Loren M. (Inventor); Tang, Shoou-Yu (Inventor); O'Brien, Martin J. (Inventor)

2009-01-01

A method for remotely sensing air outside a moving aircraft includes generating laser radiation within a swept frequency range. A portion of the laser radiation is projected from the aircraft into the air to induce scattered laser radiation. Filtered scattered laser radiation, filtered laser radiation, and unfiltered laser radiation are detected. At least one actual ratio is determined from data corresponding to the filtered scattered laser radiation and the unfiltered laser radiation. One or more air parameters are determined by correlating the actual ratio to at least one reference ratio.

Optical air data systems and methods

NASA Technical Reports Server (NTRS)

Caldwell, Loren M. (Inventor); O'Brien, Martin J. (Inventor); Tang, Shoou-Yu (Inventor)

2011-01-01

A method for remotely sensing air outside a moving aircraft includes generating laser radiation within a swept frequency range. A portion of the laser radiation is projected from the aircraft into the air to induce scattered laser radiation. Filtered scattered laser radiation, filtered laser radiation, and unfiltered laser radiation are detected. At least one actual ratio is determined from data corresponding to the filtered scattered laser radiation and the unfiltered laser radiation. One or more air parameters are determined by correlating the actual ratio to at least one reference ratio.

[Reduction of livestock-associated methicillin-resistant staphylococcus aureus (LA-MRSA) in the exhaust air of two piggeries by a bio-trickling filter and a biological three-step air cleaning system].

PubMed

Clauss, Marcus; Schulz, Jochen; Stratmann-Selke, Janin; Decius, Maja; Hartung, Jörg

2013-01-01

"Livestock-associated" Methicillin-resistent Staphylococcus aureus (LA-MRSA) are frequently found in the air of piggeries, are emitted into the ambient air of the piggeries and may also drift into residential areas or surrounding animal husbandries.. In order to reduce emissions from animal houses such as odour, gases and dust different biological air cleaning systems are commercially available. In this study the retention efficiencies for the culturable LA-MRSA of a bio-trickling filter and a combined three step system, both installed at two different piggeries, were investigated. Raw gas concentrations for LA-MRSA of 2.1 x 10(2) cfu/m3 (biotrickling filter) and 3.9 x 10(2) cfu/m3 (three step system) were found. The clean gas concentrations were in each case approximately one power of ten lower. Both systems were able to reduce the number of investigated bacteria in the air of piggeries on average about 90%. The investigated systems can contribute to protect nearby residents. However, considerable fluctuations of the emissions can occur.

Removal of viable bioaerosol particles with a low-efficiency HVAC filter enhanced by continuous emission of unipolar air ions.

PubMed

Huang, R; Agranovski, I; Pyankov, O; Grinshpun, S

2008-04-01

Continuous emission of unipolar ions has been shown to improve the performance of respirators and stationary filters challenged with non-biological particles. In this study, we investigated the ion-induced enhancement effect while challenging a low-efficiency heating, ventilation and air-conditioning (HVAC) filter with viable bacterial cells, bacterial and fungal spores, and viruses. The aerosol concentration was measured in real time. Samples were also collected with a bioaerosol sampler for viable microbial analysis. The removal efficiency of the filter was determined, respectively, with and without an ion emitter. The ionization was found to significantly enhance the filter efficiency in removing viable biological particles from the airflow. For example, when challenged with viable bacteria, the filter efficiency increased as much as four- to fivefold. For viable fungal spores, the ion-induced enhancement improved the efficiency by a factor of approximately 2. When testing with virus-carrying liquid droplets, the original removal efficiency provided by the filter was rather low: 9.09 +/- 4.84%. While the ion emission increased collection about fourfold, the efficiency did not reach 75-100% observed with bacteria and fungi. These findings, together with our previously published results for non-biological particles, demonstrate the feasibility of a new approach for reducing aerosol particles in HVAC systems used for indoor air quality control. Recirculated air in HVAC systems used for indoor air quality control in buildings often contains considerable number of viable bioaerosol particles because of limited efficiency of the filters installed in these systems. In the present study, we investigated - using aerosolized bacterial cells, bacterial and fungal spores, and virus-carrying particles - a novel idea of enhancing the performance of a low-efficiency HVAC filter utilizing continuous emission of unipolar ions in the filter vicinity. The findings described in this paper, together with our previously published results for non-biological particles, demonstrate the feasibility of the newly developed approach.

Low pressure EGR system having full range capability

DOEpatents

Easley, Jr., William Lanier; Milam, David Michael; Roozenboom, Stephan Donald; Bond, Michael Steven; Kapic, Amir

2009-09-22

An exhaust treatment system for an engine is disclosed and may have an air induction circuit, an exhaust circuit, and an exhaust recirculation circuit. The air induction circuit may be configured to direct air into the engine. The exhaust circuit may be configured to direct exhaust from the engine and include a turbine driven by the exhaust, a particulate filter disposed in series with and downstream of the turbine, and a catalytic device disposed in series with and downstream of the particulate filter. The exhaust recirculation circuit may be configured to selectively redirect at least some of the exhaust from between the particulate filter and the catalytic device to the air induction circuit. The catalytic device is selected to create backpressure within the exhaust circuit sufficient to ensure that, under normal engine operating conditions above low idle, exhaust can flow into the air induction circuit without throttling of the air.

Development of Test Protocols for International Space Station Particulate Filters

NASA Technical Reports Server (NTRS)

Green, Robert D.; Vijayakumar, R.; Agui, Juan H.

2014-01-01

Air quality control on the International Space Station (ISS) is a vital requirement for maintaining a clean environment for the crew and the hardware. This becomes a serious challenge in pressurized space compartments since no outside air ventilation is possible, and a larger particulate load is imposed on the filtration system due to lack of gravitational settling. The ISS Environmental Control and Life Support System (ECLSS) uses a filtration system that has been in use for over 14 years and has proven to meet this challenge. The heart of this system is a traditional High- Efficiency Particulate Air (HEPA) filter configured to interface with the rest of the life support elements and provide effective cabin filtration. Over the years, the service life of these filters has been re-evaluated based on limited post-flight tests of returned filters and risk factors. On earth, a well designed and installed HEPA filter will last for several years, e.g. in industrial and research clean room applications. Test methods for evaluating these filters are being developed on the basis of established test protocols used by the industry and the military. This paper will discuss the test methods adopted and test results on prototypes of the ISS filters. The results will assist in establishing whether the service life can be extended for these filters. Results from unused filters that have been in storage will also be presented to ascertain the shelf life and performance deterioration, if any and determine if the shelf life may be extended.

Airborne irritant contact dermatitis due to synthetic fibres from an air-conditioning filter.

PubMed

Patiwael, Jiska A; Wintzen, Marjolein; Rustemeyer, Thomas; Bruynzeel, Derk P

2005-03-01

We describe 8 cases of occupational airborne irritant contact dermatitis in intensive care unit (ICU) employees caused by synthetic (polypropylene and polyethylene) fibres from an air-conditioning filter. Not until a workplace investigation was conducted, was it possible to clarify the unusual sequence of events. High filter pressure in the intensive care air-conditioning system, maintained to establish an outward airflow and prevent microorganisms from entering the ward, probably caused fibres from the filter to become airborne. Upon contact with air-exposed skin, fibres subsequently provoked skin irritation. Test periods in the ICU with varying filter pressures, in an attempt to improve environmental conditions, led to even higher filter pressure levels and more complaints. The sometimes-very-low humidity might have contributed to development of skin irritation. The fact that most patients recovered quickly after treatment with emollients and changing the filters made it most likely that the airborne dermatitis was of an irritant nature.

Efficiency of automotive cabin air filters to reduce acute health effects of diesel exhaust in human subjects

PubMed Central

Rudell, B.; Wass, U.; Horstedt, P.; Levin, J. O.; Lindahl, R.; Rannug, U.; Sunesson, A. L.; Ostberg, Y.; Sandstrom, T.

1999-01-01

OBJECTIVES: To evaluate the efficiency of different automotive cabin air filters to prevent penetration of components of diesel exhaust and thereby reduce biomedical effects in human subjects. Filtered air and unfiltered diluted diesel exhaust (DDE) were used as negative and positive controls, respectively, and were compared with exposure to DDE filtered with four different filter systems. METHODS: 32 Healthy non- smoking subjects (age 21-53) participated in the study. Each subject was exposed six times for 1 hour in a specially designed exposure chamber: once to air, once to unfiltered DDE, and once to DDE filtered with the four different cabin air filters. Particle concentrations during exposure to unfiltered DDE were kept at 300 micrograms/m3. Two of the filters were particle filters. The other two were particle filters combined with active charcoal filters that might reduce certain gaseous components. Subjective symptoms were recorded and nasal airway lavage (NAL), acoustic rhinometry, and lung function measurements were performed. RESULTS: The two particle filters decreased the concentrations of diesel exhaust particles by about half, but did not reduce the intensity of symptoms induced by exhaust. The combination of active charcoal filters and a particle filter significantly reduced the symptoms and discomfort caused by the diesel exhaust. The most noticable differences in efficacy between the filters were found in the reduction of detection of an unpleasant smell from the diesel exhaust. In this respect even the two charcoal filter combinations differed significantly. The efficacy to reduce symptoms may depend on the abilities of the filters investigated to reduce certain hydrocarbons. No acute effects on NAL, rhinometry, and lung function variables were found. CONCLUSIONS: This study has shown that the use of active charcoal filters, and a particle filter, clearly reduced the intensity of symptoms induced by diesel exhaust. Complementary studies on vehicle cabin air filters may result in further diminishing the biomedical effects of diesel exhaust in subjects exposed in traffic and workplaces.   PMID:10450238

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

Smith, T; Graham, C L; Sundsmo, T

This procedure provides instructions for the calibration and use of the Canberra iSolo Low Background Alpha/Beta Counting System (iSolo) that is used for counting air filters and swipe samples. This detector is capable of providing radioisotope identification (e.g., it can discriminate between radon daughters and plutonium). This procedure includes step-by-step instructions for: (1) Performing periodic or daily 'Background' and 'Efficiency QC' checks; (2) Setting-up the iSolo for counting swipes and air filters; (3) Counting swipes and air filters for alpha and beta activity; and (4) Annual calibration.

Air Cleaning Devices for HVAC Supply Systems in Schools. Technical Bulletin.

ERIC Educational Resources Information Center

Wheeler, Arthur E.

Guidelines for maintaining indoor air quality in schools with HVAC air cleaning systems are provided in this document. Information is offered on the importance of air cleaning, sources of air contaminants and indoor pollutants, types of air cleaners and particulate filters used in central HVAC systems, vapor and gas removal, and performance…

Operation JANGLE. Particle Studies. Projects 2.5a-1, 2.5a-2, 2.5a-3, 2. 8,

DTIC Science & Technology

1979-10-01

air with time. 26.1 Brookhaven Air Monitor A filter paper feed system traveling at 4 inches per hour combined with a vacuum pump (3.5 ou ft/min) was...Monitor This Instrument also employs an air pumping system (2.6 cu.ft/min) with filter paper 6 Inohes wide traveling at 7 inches per hour or multiples...JANGLE of the Portable Air Sampler (PAS) used previously by Test Division, CRL and Dug.way Proving Ground, Utah. Its purpose was to pro- vde an

40 CFR 610.21 - Device functional category and vehicle system effects.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 1 Device categories Characteristics adversely affected Fuel-Air System Carburetors and fuel injection systems All. Air-fuel ratio modifiers (e.g., air bleeds) All. Atomization devices (acoustic and mechanical) All. Vapor Injectors All. Choke controls 1, 2, and 4. Air filters 1, 2, and 4. Fuel-air...

40 CFR 610.21 - Device functional category and vehicle system effects.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 1 Device categories Characteristics adversely affected Fuel-Air System Carburetors and fuel injection systems All. Air-fuel ratio modifiers (e.g., air bleeds) All. Atomization devices (acoustic and mechanical) All. Vapor Injectors All. Choke controls 1, 2, and 4. Air filters 1, 2, and 4. Fuel-air...

Composition of the excimer laser-induced plume produced during LASIK refractive surgery

NASA Astrophysics Data System (ADS)

Glickman, Randolph D.; Liu, Yun; Mayo, George L.; Baribeau, Alan D.; Starck, Tomy; Bankhead, Tom

2003-07-01

Because of concerns about potential hazards to surgical personnel of the plume associated with laser refractive surgery, this study was performed to characterize the composition of such plumes. Filter elements were removed from the smoke evacuator of a VISX S3 excimer laser (filter pore size ~0.3 microns) and from a Mastel Clean Room ( filter pore size ~0.2 microns) used with a LADARVISION excimer laser. The filters from both laser systems captured the laser-induced plumes from multiple, routine, LASIK patient procedures. Some filters were processed for scanning electron microscopy, while others were extracted with methanol and chloroform for biochemical analysis. Both the VISX "Final Air" filter and the Mastel "Clean Room" filter captured material that was not observed in filters that had clean operating room air only passed through them. In the VISX system, air flows through the filter unit parallel to the filter matrix. SEM analysis showed these filters captured discrete particles of 0.3 to 3.0 microns in size. In the Mastel Clean Room unit, air flows orthogonally through the filter, and the filter matrix was heavily layered with captured debris so that individual particles were not readily distinguished. Amino acid analysis and gel electrophoresis of extracted material revealed proteinaceous molecules as large as 5000 molecular weight. Such large molecules in the laser plume are not predicted by the existing theory of photochemical ablation. The presence of relatively large biomolecules may constitute a risk of allergenic reactions in personnel exposed to the plume, and also calls into question the precise mechanism of excimer laser photochemical ablation. Supported by the RMG Research Endowment, and Research to Prevent Blindness

The Fate of Mengovirus on Fiberglass Filter of Air Handling Units.

PubMed

Bandaly, Victor; Joubert, Aurélie; Le Cann, Pierre; Andres, Yves

2017-12-01

One of the most important topics that occupy public health problems is the air quality. That is the reason why mechanical ventilation and air handling units (AHU) were imposed by the different governments in the collective or individual buildings. Many buildings create an artificial climate using heating, ventilation, and air-conditioning systems. Among the existing aerosols in the indoor air, we can distinguish the bioaerosol with biological nature such as bacteria, viruses, and fungi. Respiratory viral infections are a major public health issue because they are usually highly infective. We spend about 90% of our time in closed environments such as homes, workplaces, or transport. Some studies have shown that AHU contribute to the spread and transport of viral particles within buildings. The aim of this work is to study the characterization of viral bioaerosols in indoor environments and to understand the fate of mengovirus eukaryote RNA virus on glass fiber filter F7 used in AHU. In this study, a set-up close to reality of AHU system was used. The mengovirus aerosolized was characterized and measured with the electrical low pressure impact and the scanner mobility particle size and detected with RT-qPCR. The results about quantification and the level of infectivity of mengovirus on the filter and in the biosampler showed that mengovirus can pass through the filter and remain infectious upstream and downstream the system. Regarding the virus infectivity on the filter under a constant air flow, mengovirus was remained infectious during 10 h after aerosolization.

System for controlling child safety seat environment

NASA Technical Reports Server (NTRS)

Elrod, Susan V. (Inventor); Dabney, Richard W. (Inventor)

2008-01-01

A system is provided to control the environment experienced by a child in a child safety seat. Each of a plurality of thermoelectric elements is individually controllable to be one of heated and cooled relative to an ambient temperature. A first portion of the thermoelectric elements are positioned on the child safety seat such that a child sitting therein is positioned thereover. A ventilator coupled to the child safety seat moves air past a second portion of the thermoelectric elements and filters the air moved therepast. One or more jets coupled to the ventilator receive the filtered air. Each jet is coupled to the child safety seat and can be positioned to direct the heated/cooled filtered air to the vicinity of the head of the child sitting in the child safety seat.

Reducing patients' exposures to asthma and allergy triggers in their homes: an evaluation of effectiveness of grades of forced air ventilation filters.

PubMed

Brown, Kathleen Ward; Minegishi, Taeko; Allen, Joseph G; McCarthy, John F; Spengler, John D; MacIntosh, David L

2014-08-01

Many interventions to reduce allergen levels in the home are recommended to asthma and allergy patients. One that is readily available and can be highly effective is the use of high performing filters in forced air ventilation systems. We conducted a modeling analysis of the effectiveness of filter-based interventions in the home to reduce airborne asthma and allergy triggers. This work used "each pass removal efficiency" applied to health-relevant size fractions of particles to assess filter performance. We assessed effectiveness for key allergy and asthma triggers based on applicable particle sizes for cat allergen, indoor and outdoor sources of particles <2.5 µm in diameter (PM2.5), and airborne influenza and rhinovirus. Our analysis finds that higher performing filters can have significant impacts on indoor particle pollutant levels. Filters with removal efficiencies of >70% for cat dander particles, fine particulate matter (PM2.5) and respiratory virus can lower concentrations of those asthma triggers and allergens in indoor air of the home by >50%. Very high removal efficiency filters, such as those rated a 16 on the nationally recognized Minimum Efficiency Removal Value (MERV) rating system, tend to be only marginally more effective than MERV12 or 13 rated filters. The results of this analysis indicate that use of a MERV12 or higher performing air filter in home ventilation systems can effectively reduce indoor levels of these common asthma and allergy triggers. These reductions in airborne allergens in turn may help reduce allergy and asthma symptoms, especially if employed in conjunction with other environmental management measures recommended for allergy and asthma patients.

Reducing patients’ exposures to asthma and allergy triggers in their homes: an evaluation of effectiveness of grades of forced air ventilation filters

PubMed Central

Minegishi, Taeko; Allen, Joseph G.; McCarthy, John F.; Spengler, John D.; MacIntosh, David L.

2014-01-01

Objective Many interventions to reduce allergen levels in the home are recommended to asthma and allergy patients. One that is readily available and can be highly effective is the use of high performing filters in forced air ventilation systems. Methods We conducted a modeling analysis of the effectiveness of filter-based interventions in the home to reduce airborne asthma and allergy triggers. This work used “each pass removal efficiency” applied to health-relevant size fractions of particles to assess filter performance. We assessed effectiveness for key allergy and asthma triggers based on applicable particle sizes for cat allergen, indoor and outdoor sources of particles <2.5 µm in diameter (PM2.5), and airborne influenza and rhinovirus. Results Our analysis finds that higher performing filters can have significant impacts on indoor particle pollutant levels. Filters with removal efficiencies of >70% for cat dander particles, fine particulate matter (PM2.5) and respiratory virus can lower concentrations of those asthma triggers and allergens in indoor air of the home by >50%. Very high removal efficiency filters, such as those rated a 16 on the nationally recognized Minimum Efficiency Removal Value (MERV) rating system, tend to be only marginally more effective than MERV12 or 13 rated filters. Conclusions The results of this analysis indicate that use of a MERV12 or higher performing air filter in home ventilation systems can effectively reduce indoor levels of these common asthma and allergy triggers. These reductions in airborne allergens in turn may help reduce allergy and asthma symptoms, especially if employed in conjunction with other environmental management measures recommended for allergy and asthma patients. PMID:24555523

78 FR 27951 - Foreign-Trade Zone (FTZ) 75-Phoenix, Arizona; Notification of Proposed Production Activity...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-05-13

... systems; duct temperature limiters; air/oil heat exchangers; oil cooler fans; fuel filter assemblies... assemblies; filter extractors; de- coupler/disassembly wrenches; torque wrench adaptors; test benches; drills...; filter assemblies; oil filter install kits; cartridge screens; filter housings; trim balance weights...

High Efficiency Particulate Air (HEPA) Filter Generation, Characterization, and Disposal Experiences at the Oak Ridge National Laboratory

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

Coffey, D. E.

2002-02-28

High Efficiency Particulate Air filtration is an essential component of the containment and ventilation systems supporting the research and development activities at the Oak Ridge National Laboratory. High Efficiency Particulate Air filters range in size from 7.6cm (3 inch) by 10.2 cm (4 inch) cylindrical shape filters to filter array assemblies up to 2.1 m (7 feet) high by 1.5 m (5 feet) wide. Spent filters are grouped by contaminates trapped in the filter media and become one of the components in the respective waste stream. Waste minimization and pollution prevention efforts are applied for both radiological and non-radiological applications.more » Radiological applications include laboratory hoods, glove boxes, and hot cells. High Efficiency Particulate Air filters also are generated from intake or pre-filtering applications, decontamination activities, and asbestos abatement applications. The disposal avenues include sanitary/industrial waste, Resource Conservation and Recovery Act and Toxic Substance Control Act, regulated waste, solid low-level waste, contact handled transuranic, and remote handled transuranic waste. This paper discusses characterization and operational experiences associated with the disposal of the spent filters across multiple applications.« less

Quantitative filter forensics for indoor particle sampling.

PubMed

Haaland, D; Siegel, J A

2017-03-01

Filter forensics is a promising indoor air investigation technique involving the analysis of dust which has collected on filters in central forced-air heating, ventilation, and air conditioning (HVAC) or portable systems to determine the presence of indoor particle-bound contaminants. In this study, we summarize past filter forensics research to explore what it reveals about the sampling technique and the indoor environment. There are 60 investigations in the literature that have used this sampling technique for a variety of biotic and abiotic contaminants. Many studies identified differences between contaminant concentrations in different buildings using this technique. Based on this literature review, we identified a lack of quantification as a gap in the past literature. Accordingly, we propose an approach to quantitatively link contaminants extracted from HVAC filter dust to time-averaged integrated air concentrations. This quantitative filter forensics approach has great potential to measure indoor air concentrations of a wide variety of particle-bound contaminants. Future studies directly comparing quantitative filter forensics to alternative sampling techniques are required to fully assess this approach, but analysis of past research suggests the enormous possibility of this approach. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

The long-term performance of electrically charged filters in a ventilation system.

PubMed

Raynor, Peter C; Chae, Soo Jae

2004-07-01

The efficiency and pressure drop of filters made from polyolefin fibers carrying electrical charges were compared with efficiency and pressure drop for filters made from uncharged glass fibers to determine if the efficiency of the charged filters changed with use. Thirty glass fiber filters and 30 polyolefin fiber filters were placed in different, but nearly identical, air-handling units that supplied outside air to a large building. Using two kinds of real-time aerosol counting and sizing instruments, the efficiency of both sets of filters was measured repeatedly for more than 19 weeks while the air-handling units operated almost continuously. Pressure drop was recorded by the ventilation system's computer control. Measurements showed that the efficiency of the glass fiber filters remained almost constant with time. However, the charged polyolefin fiber filters exhibited large efficiency reductions with time before the efficiency began to increase again toward the end of the test. For particles 0.6 microm in diameter, the efficiency of the polyolefin fiber filters declined from 85% to 45% after 11 weeks before recovering to 65% at the end of the test. The pressure drops of the glass fiber filters increased by about 0.40 in. H2O, whereas the pressure drop of the polyolefin fiber filters increased by only 0.28 in. H2O. The results indicate that dust loading reduces the effectiveness of electrical charges on filter fibers. Copyright 2004 JOEH, LLC

Incident-response monitoring technologies for aircraft cabin air quality

NASA Astrophysics Data System (ADS)

Magoha, Paul W.

Poor air quality in commercial aircraft cabins can be caused by volatile organophosphorus (OP) compounds emitted from the jet engine bleed air system during smoke/fume incidents. Tri-cresyl phosphate (TCP), a common anti-wear additive in turbine engine oils, is an important component in today's global aircraft operations. However, exposure to TCP increases risks of certain adverse health effects. This research analyzed used aircraft cabin air filters for jet engine oil contaminants and designed a jet engine bleed air simulator (BAS) to replicate smoke/fume incidents caused by pyrolysis of jet engine oil. Field emission scanning electron microscopy (FESEM) with X-ray energy dispersive spectroscopy (EDS) and neutron activation analysis (NAA) were used for elemental analysis of filters, and gas chromatography interfaced with mass spectrometry (GC/MS) was used to analyze used filters to determine TCP isomers. The filter analysis study involved 110 used and 90 incident filters. Clean air filter samples exposed to different bleed air conditions simulating cabin air contamination incidents were also analyzed by FESEM/EDS, NAA, and GC/MS. Experiments were conducted on a BAS at various bleed air conditions typical of an operating jet engine so that the effects of temperature and pressure variations on jet engine oil aerosol formation could be determined. The GC/MS analysis of both used and incident filters characterized tri- m-cresyl phosphate (TmCP) and tri-p-cresyl phosphate (TpCP) by a base peak of an m/z = 368, with corresponding retention times of 21.9 and 23.4 minutes. The hydrocarbons in jet oil were characterized in the filters by a base peak pattern of an m/z = 85, 113. Using retention times and hydrocarbon thermal conductivity peak (TCP) pattern obtained from jet engine oil standards, five out of 110 used filters tested had oil markers. Meanwhile 22 out of 77 incident filters tested positive for oil fingerprints. Probit analysis of jet engine oil aerosols obtained from BAS tests by optical particle counter (OPC) revealed lognormal distributions with the mean (range) of geometric mass mean diameter (GMMD) = 0.41 (0.39, 0.45) microm and geometric standard deviation (GSD), sigma g = 1.92 (1.87, 1.98). FESEM/EDS and NAA techniques found a wide range of elements on filters, and further investigations of used filters are recommended using these techniques. The protocols for air and filter sampling and GC/MS analysis used in this study will increase the options available for detecting jet engine oil on cabin air filters. Such criteria could support policy development for compliance with cabin air quality standards during incidents.

Evaluation of an air-filtration system for preventing aerosol transmission of Porcine reproductive and respiratory syndrome virus

PubMed Central

2005-01-01

Abstract The purpose of this study was to evaluate the ability of a commercial air-filtration system to reduce aerosol transmission of Porcine reproductive and respiratory syndrome virus (PRRSV). The system consisted of a pre-filter and 2 filters with EU8 and EU13 ratings. In each of 4 trials, 5 PRRSV-infected donor pigs and 1 naïve recipient pig (each 25 kg) were housed in opposing chambers connected by a 1.3-m-long duct. The system filtered air entering 1 recipient-pig chamber (filtered facility) from the donor- chamber but not a 2nd recipient-pig chamber (nonfiltered facility). The donor pigs had been experimentally infected with PRRSV MN-184, an isolate previously documented to be shed at a high frequency in contagious aerosols. On days 3 to 7 after infection of the donors, the 2 groups were housed in their respective chambers for 6 h and then in separate facilities, where samples were collected for testing by polymerase chain reaction and enzyme-linked immunosorbent assay over 14 d. Aerosol transmission was observed in 6 of the 20 replicates in the nonfiltered facility, whereas all pigs remained PRRSV-negative in the filtered facility; the difference was significant at P < 0.01. Thus, under the conditions of this study, the air-filtration system evaluated appeared to be highly effective at reducing aerosol transmission of PRRSV. PMID:16479728

Background culturable bacteria aerosol in two large public buildings using HVAC filters as long term, passive, high-volume air samplers.

PubMed

Stanley, Nicholas J; Kuehn, Thomas H; Kim, Seung Won; Raynor, Peter C; Anantharaman, Senthilvelan; Ramakrishnan, M A; Goyal, Sagar M

2008-04-01

Background culturable bacteria aerosols were collected and identified in two large public buildings located in Minneapolis, Minnesota and Seattle, Washington over a period of 5 months and 3 months, respectively. The installed particulate air filters in the ventilation systems were used as the aerosol sampling devices at each location. Both pre and final filters were collected from four air handing units at each site to determine the influence of location within the building, time of year, geographical location and difference between indoor and outdoor air. Sections of each loaded filter were eluted with 10 ml of phosphate buffered saline (PBS). The resulting solutions were cultured on blood agar plates and incubated for 24 h at 36 degrees C. Various types of growth media were then used for subculturing, followed by categorization using a BioLog MicroStation (Biolog, Hayward, CA, USA) and manual observation. Environmental parameters were gathered near each filter by the embedded on-site environmental monitoring systems to determine the effect of temperature, humidity and air flow. Thirty nine different species of bacteria were identified, 17 found only in Minneapolis and 5 only in Seattle. The hardy spore-forming genus Bacillus was the most commonly identified and showed the highest concentrations. A significant decrease in the number of species and their concentration occurred in the Minneapolis air handling unit supplying 100% outdoor air in winter, however no significant correlations between bacteria concentration and environmental parameters were found.

Numerical study on self-cleaning canister filter with modified filter cap

NASA Astrophysics Data System (ADS)

Mohammed, Akmal Nizam; Zolkhaely, Mohd Hafiz; Sahrudin, Mohd Sahrizan; Razali, Mohd Azahari; Sapit, Azwan; Hushim, Mohd Faisal

2017-04-01

Air filtration system plays an important role in getting good quality air into turbo machinery such as gas turbine. The filtration system and filters improve the quality of air and protect the gas turbine parts from contaminants which could bring damage. This paper is focused on the configuration of the self-cleaning canister filter in order to obtain the minimal pressure drop along the filter. The configuration includes a modified canister filter cap that is based on the basic geometry that conforms to industry standard. This paper describes the use of CFD to simulate and analyze the flow through the filter. This tool is also used to monitor variables such as pressure and velocity along the filter and to visualize them in the form of contours, vectors and streamlines. In this study, the main parameter varied is the inlet velocity set in the boundary condition during simulations, which are 0.032, 0.063, 0.094 and 0.126 m/s respectively. The data obtained from simulations are then validated with reference data sourced from the industry, and comparisons have subsequently been made for these two filters. As a result, the improvement of the pressure drop for the modified filter is found to be 11.47% to 14.82% compared to the basic filter at the inlet velocity from 0.032 to 0.126 m/s. the total pressure drop produced is 292.3 Pa by the basic filter and 251.11 Pa for modified filter. The pressure drop reduction is 41.19 Pa, which is 14.1% from the basic filter.

Testing Air-Filtering Systems

PubMed Central

Songer, Joseph R.; Sullivan, James F.; Hurd, James W.

1963-01-01

A procedure was developed for evaluating high-efficiency filters mounted in exhaust ducts at the National Animal Disease Laboratory. An aerosol of the test organism, Escherichia coli B T3 bacteriophage, was generated in a chamber attached to a ceiling exhaust register in concentrations of at least 1000 viable organisms per ft3 of air. Samples were collected from both the pre- and postfilter areas, and the number of organisms per ft3 of air was determined. The efficiency of the filter was calculated from these figures. A total of 269 high-efficiency filters were tested. Of these, 249 had efficiencies of 98% or greater. The remaining 20, with efficiencies of less than 98%, were repaired and retested. No filter was accepted with an efficiency of less than 98%. Images Fig. 2 PMID:14063779

Enhanced performance of a filter-sensor system.

PubMed

Sasaki, Isao; Josowicz, Mira; Janata, Jirí; Glezer, Ari

2006-06-01

In this paper are addressed two important, but seemingly unrelated issues: long term performance of a gas sensing array and performance of an air purification unit. It is shown that when considered together, the system can be regarded as a "smart filter". The enhancement is achieved by periodic differential sampling and measurement of the "upstream" and "downstream" gases of a filter. The correctly functioning filter supplies the "zero gas" from the downstream for the continuous sensor baseline correction. A key element in this scheme is the synthetic jet that delivers well-defined pulses of the two gases. The deterioration of the performance of the "smart filter" can be diagnosed from the response pattern of the sensor. The approach has been demonstrated on removal/sensing of ammonia gas from air.

40 CFR 63.864 - Monitoring requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... that uses an air pollution control system other than an ESP, wet scrubber, RTO, or fabric filter must... unit equipped with an alternative air pollution control system and monitoring operating parameters... affected source or process unit equipped with an alternative air pollution control system and monitoring...

40 CFR 63.864 - Monitoring requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... that uses an air pollution control system other than an ESP, wet scrubber, RTO, or fabric filter must... unit equipped with an alternative air pollution control system and monitoring operating parameters... affected source or process unit equipped with an alternative air pollution control system and monitoring...

40 CFR 63.864 - Monitoring requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... that uses an air pollution control system other than an ESP, wet scrubber, RTO, or fabric filter must... unit equipped with an alternative air pollution control system and monitoring operating parameters... affected source or process unit equipped with an alternative air pollution control system and monitoring...

Evaluation of environmental filtration control of engineered nanoparticles using the Harvard Versatile Engineered Nanomaterial Generation System (VENGES)

NASA Astrophysics Data System (ADS)

Tsai, Candace S.-J.; Echevarría-Vega, Manuel E.; Sotiriou, Georgios A.; Santeufemio, Christopher; Schmidt, Daniel; Demokritou, Philip; Ellenbecker, Michael

2012-05-01

Applying engineering controls to airborne engineered nanoparticles (ENPs) is critical to prevent environmental releases and worker exposure. This study evaluated the effectiveness of two air sampling and six air cleaning fabric filters at collecting ENPs using industrially relevant flame-made engineered nanoparticles generated using a versatile engineered nanomaterial generation system (VENGES), recently designed and constructed at Harvard University. VENGES has the ability to generate metal and metal oxide exposure atmospheres while controlling important particle properties such as primary particle size, aerosol size distribution, and agglomeration state. For this study, amorphous SiO2 ENPs with a 15.4 nm primary particle size were generated and diluted with HEPA-filtered air. The aerosol was passed through the filter samples at two different filtration face velocities (2.3 and 3.5 m/min). Particle concentrations as a function of particle size were measured upstream and downstream of the filters using a specially designed filter test system to evaluate filtration efficiency. Real time instruments (FMPS and APS) were used to measure particle concentration for diameters from 5 to 20,000 nm. Membrane-coated fabric filters were found to have enhanced nanoparticle collection efficiency by 20-46 % points compared to non-coated fabric and could provide collection efficiency above 95 %.

Evaluation of environmental filtration control of engineered nanoparticles using the Harvard Versatile Engineered Nanomaterial Generation System (VENGES)

PubMed Central

Echevarría-Vega, Manuel E.; Sotiriou, Georgios A.; Santeufemio, Christopher; Schmidt, Daniel; Demokritou, Philip; Ellenbecker, Michael

2013-01-01

Applying engineering controls to airborne engineered nanoparticles (ENPs) is critical to prevent environmental releases and worker exposure. This study evaluated the effectiveness of two air sampling and six air cleaning fabric filters at collecting ENPs using industrially relevant flame-made engineered nanoparticles generated using a versatile engineered nanomaterial generation system (VENGES), recently designed and constructed at Harvard University. VENGES has the ability to generate metal and metal oxide exposure atmospheres while controlling important particle properties such as primary particle size, aerosol size distribution, and agglomeration state. For this study, amorphous SiO2 ENPs with a 15.4 nm primary particle size were generated and diluted with HEPA-filtered air. The aerosol was passed through the filter samples at two different filtration face velocities (2.3 and 3.5 m/min). Particle concentrations as a function of particle size were measured upstream and downstream of the filters using a specially designed filter test system to evaluate filtration efficiency. Real time instruments (FMPS and APS) were used to measure particle concentration for diameters from 5 to 20,000 nm. Membrane-coated fabric filters were found to have enhanced nanoparticle collection efficiency by 20–46 % points compared to non-coated fabric and could provide collection efficiency above 95 %. PMID:23412707

Development of Test Protocols for International Space Station Particulate Filters

NASA Technical Reports Server (NTRS)

Vijayakumar, R.; Green, Robert D.; Agui, Juan H.

2015-01-01

Air quality control on the International Space Station (ISS) is a vital requirement for maintaining a clean environment for the crew and the hardware. This becomes a serious challenge in pressurized space compartments since no outside air ventilation is possible, and a larger particulate load is imposed on the filtration system due to lack of gravitational settling. The ISS Environmental Control and Life Support System (ECLSS) uses a filtration system that has been in use for over 14 years and has proven to meet this challenge. The heart of this system is a traditional High-Efficiency Particulate Air (HEPA) filter configured to interface with the rest of the life support elements and provide effective cabin filtration. The filter element for this system has a non-standard cross-section with a length-to-width ratio (LW) of 6.6. A filter test setup was designed and built to meet industry testing standards. A CFD analysis was performed to initially determine the optimal duct geometry and flow configuration. Both a screen and flow straighter were added to the test duct design to improve flow uniformity and face velocity profiles were subsequently measured to confirm. Flow quality and aerosol mixing assessments show that the duct flow is satisfactory for the intended leak testing. Preliminary leak testing was performed on two different ISS filters, one with known perforations and one with limited use, and results confirmed that the testing methods and photometer instrument are sensitive enough to detect and locate compromised sections of an ISS BFE.Given the engineering constraints in designing spacecraft life support systems, it is anticipated that non-industry standard filters will be required in future designs. This work is focused on developing test protocols for testing the ISS BFE filters, but the methodology is general enough to be extended to other present and future spacecraft filters. These techniques for characterizing the test duct and perform leak testing can be applied to conducting acceptance testing and inventory testing for future manned exploration programs with air revitalization filtration needs, possibly even for in-situ filter element integrity testing for extensively long-duration missions. We plan to address the unique needs for test protocols for crewed spacecraft particulate filters by preparing the initial version of a standard, to be documented as a NASA Technical Memorandum (TM).

Collection of biological and non-biological particles by new and used filters made from glass and electrostatically charged synthetic fibers.

PubMed

Raynor, P C; Kim, B G; Ramachandran, G; Strommen, M R; Horns, J H; Streifel, A J

2008-02-01

Synthetic filters made from fibers carrying electrostatic charges and fiberglass filters that do not carry electrostatic charges are both utilized commonly in heating, ventilating, and air-conditioning (HVAC) systems. The pressure drop and efficiency of a bank of fiberglass filters and a bank of electrostatically charged synthetic filters were measured repeatedly for 13 weeks in operating HVAC systems at a hospital. Additionally, the efficiency with which new and used fiberglass and synthetic filters collected culturable biological particles was measured in a test apparatus. Pressure drop measurements adjusted to equivalent flows indicated that the synthetic filters operated with a pressure drop less than half that of the fiberglass filters throughout the test. When measured using total ambient particles, synthetic filter efficiency decreased during the test period for all particle diameters. For particles 0.7-1.0 mum in diameter, efficiency decreased from 92% to 44%. It is hypothesized that this reduction in collection efficiency may be due to charge shielding. Efficiency did not change significantly for the fiberglass filters during the test period. However, when measured using culturable biological particles in the ambient air, efficiency was essentially the same for new filters and filters used for 13 weeks in the hospital for both the synthetic and fiberglass filters. It is hypothesized that the lack of efficiency reduction for culturable particles may be due to their having higher charge than non-biological particles, allowing them to overcome the effects of charge shielding. The type of particles requiring capture may be an important consideration when comparing the relative performance of electrostatically charged synthetic and fiberglass filters. Electrostatically charged synthetic filters with high initial efficiency can frequently replace traditional fiberglass filters with lower efficiency in HVAC systems because properly designed synthetic filters offer less resistance to air flow. Although the efficiency of charged synthetic filters at collecting non-biological particles declined substantially with use, the efficiency of these filters at collecting biological particles remained steady. These findings suggest that the merits of electrostatically charged synthetic HVAC filters relative to fiberglass filters may be more pronounced if collection of biological particles is of primary concern.

Determination of sub-part-per-million levels of formaldehyde in air using active or passive sampling on 2,4-dinitrophenylhydrazine-coated glass fiber filters and high-performance liquid chromatography

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

Levin, J.O.; Andersson, K.; Lindahl, R.

1985-05-01

Formaldehyde is sampled from air with the use of a standard miniature glass fiber filter impregnated with 2,4-dinitrophenylhydrazine and phosphoric acid. The formaldehyde hydrazone is desorbed from the filter with acetonitrile and determined by high-performance liquid chromatography using UV detection at 365 nm. Recovery of gas-phase-generated formaldehyde as hydrazone from a 13-mm impregnated filter is 80-100% in the range 0.3-30 ..mu..g of formaldehyde. This corresponds to 0.1-10 mg/m/sup 3/ in a 3-L air sample. When the filter sampling system is used in the active mode, air can be sampled at a rate of up to 1 L/min, affording an overallmore » sensitivity of about 1 ..mu..g/m/sup 3/ based on a 60-L air sample. Results are given from measurements of formaldehyde in indoor air. The DNP-coated filters were also evaluated for passive sampling. In this case 37-mm standard glass fibers were used and the sampling rate was 55-65 mL/min in two types of dosimeters. The diffusion samplers are especially useful for personal exposure monitoring in the work environment. 24 references, 2 figures, 4 tables.« less

Apparatus and method for removing particulate deposits from high temperature filters

DOEpatents

Nakaishi, Curtis V.; Holcombe, Norman T.; Micheli, Paul L.

1992-01-01

A combustion of a fuel-air mixture is used to provide a high-temperature and high-pressure pulse of gaseous combustion products for the back-flush cleaning of ceramic filter elements contained in a barrier filter system and utilized to separate particulates from particulate-laden process gases at high temperature and high pressure. The volume of gaseous combustion products provided by the combustion of the fuel-air mixture is preferably divided into a plurality of streams each passing through a sonic orifice and conveyed to the open end of each filter element as a high pressure pulse which passes through the filter elements and dislodges dust cake supported on a surface of the filter element.

Define and Quantify the Physics of Air Flow, Pressure Drop and Aerosol Collection in Nuclear Grade HEPA Filters

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

Moore, Murray E.

Objective: Develop a set of peer-review and verified analytical methods to adjust HEPA filter performance to different flow rates, temperatures and altitudes. Experimental testing will measure HEPA filter flow rate, pressure drop and efficiency to verify the analytical approach. Nuclear facilities utilize HEPA (High Efficiency Particulate Air) filters to purify air flow for workspace ventilation. However, the ASME AG-1 technical standard (Code on Nuclear Air and Gas Treatment) does not adequately describe air flow measurement units for HEPA filter systems. Specifically, the AG-1 standard does not differentiate between volumetric air flow in ACFM (actual cubic feet per minute)compared to massmore » flow measured in SCFM (standard cubic feet per minute). More importantly, the AG-1 standard has an overall deficiency for using HEPA filter devices at different air flow rates, temperatures, and altitudes. Technical Approach: The collection efficiency and pressure drops of 18 different HEPA filters will be measured over a range of flow rates, temperatures and altitudes. The experimental results will be compared to analytical scoping calculations. Three manufacturers have allocated six HEPA filters each for this effort. The 18 filters will be tested at two different flow rates, two different temperatures and two different altitudes. The 36 total tests will be conducted at two different facilities: the ATI Test facilities (Baltimore MD) and the Los Alamos National Laboratory (Los Alamos NM). The Radiation Protection RP-SVS group at Los Alamos has an aerosol wind tunnel that was originally designed to evaluate small air samplers. In 2010, modifications were started to convert the wind tunnel for HEPA filter testing. (Extensive changes were necessary for the required aerosol generators, HEPA test fixtures, temperature control devices and measurement capabilities.) To this date, none of these modification activities have been funded through a specific DOE or NNSA program. This is expected to require six months of time, after receipt of funding. Benefits: US DOE facilities that use HEPA filters will benefit from access to the new operational measurement methods. Uncertainty and guesswork will be removed from HEPA filter operations.« less

Apparatus for real-time airborne particulate radionuclide collection and analysis

DOEpatents

Smart, John E.; Perkins, Richard W.

2001-01-01

An improved apparatus for collecting and analyzing an airborne particulate radionuclide having a filter mounted in a housing, the housing having an air inlet upstream of the filter and an air outlet downstream of the filter, wherein an air stream flows therethrough. The air inlet receives the air stream, the filter collects the airborne particulate radionuclide and permits a filtered air stream to pass through the air outlet. The improvement which permits real time counting is a gamma detecting germanium diode mounted downstream of the filter in the filtered air stream. The gamma detecting germanium diode is spaced apart from a downstream side of the filter a minimum distance for a substantially maximum counting detection while permitting substantially free air flow through the filter and uniform particulate radionuclide deposition on the filter.

ETV TEST REPORT OF CONTROL OF BIOAEROSOLS IN HVAC SYSTEMS GLASFLOSS INDUSTRIES EXCEL FILTER, MODEL SBG24242898

EPA Science Inventory

The Environmental Technology Verification report discusses the technology and performance of the Excel Filter, Model SBG24242898 air filter for dust and bioaerosol filtration manufactured by Glasfloss Industries, Inc. The pressure drop across the filter was 82 Pa clean and 348 Pa...

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

Ottney, T.C.

Filtration systems that are incorrectly selected, installed and maintained can cause excessive particulates in occupied spaces. This article describes how to identify and correct problems. Particulate matter can be removed from ventilation air at several sites within a building. These sites include: on heat exchanger surfaces; inside ductwork, ceiling tiles and diffusers; and in the air filter. The cost associated with removing these unwanted contaminants is unavoidable. However, this removal cost varies depending on where the particulates have been deposited. Not all particulates that are generated by work-related activities are transported to the filter bank by return air currents beforemore » being deposited on other surfaces. Accordingly, walls still have to be repainted at varying intervals and carpeting vacuumed. Ceiling tiles will discolor at a rate that is influenced by their texture, the air outlet velocity, the amount of dirt in the ventilation air and how much contaminant is being generated in the room. It is estimated that 15% of ventilation air escapes the air filtration process. This leakage results in higher utility, janitorial and redecorating costs as well as contributing to employee absenteeism. When building management does not prevent it, air-conditioning coils and ductwork become an unintended part of the building's air filtration system. In time, this is much more expensive both in energy and cleaning costs than the steps available to keep them clean. Good particulate control can lower the total cost of building operation. However, a building operator may not have to upgrade to a higher efficiency filter to achieve higher system efficiency. Simply eliminating the source of leaks and better management of the existing filters may be all that is necessary.« less

40 CFR 60.5225 - What are the monitoring and calibration requirements for compliance with my operating limits?

Code of Federal Regulations, 2014 CFR

2014-07-01

... limited to the following: (i) Inspecting the fabric filter for air leaks, torn or broken bags or filter... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY... maintain your bag leak detection system in continuous operation according to your monitoring plan required...

40 CFR 60.5225 - What are the monitoring and calibration requirements for compliance with my operating limits?

Code of Federal Regulations, 2013 CFR

2013-07-01

... limited to the following: (i) Inspecting the fabric filter for air leaks, torn or broken bags or filter... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY... maintain your bag leak detection system in continuous operation according to your monitoring plan required...

Self-Cleaning Particulate Prefilter Media

NASA Technical Reports Server (NTRS)

Weber, Olivia; Lalwani, San-jiv; Sharma, Anjal

2012-01-01

A long-term space mission requires efficient air revitalization performance to sustain the crew. Prefilter and particulate air filter media are susceptible to rapid fouling that adversely affects their performance and can lead to catastrophic failure of the air revitalization system, which may result in mission failure. For a long-term voyage, it is impractical to carry replacement particulate prefilter and filter modules due to the usual limitations in size, volume, and weight. The only solution to this problem is to reagentlessly regenerate prefilter and filter media in place. A method was developed to modify the particulate prefilter media to allow them to regenerate reagentlessly, and in place, by the application of modest thermocycled transverse or reversed airflows. The innovation may allow NASA to close the breathing air loop more efficiently, thereby sustaining the vision for manned space exploration missions of the future. A novel, self-cleaning coatings technology was developed for air filter media surfaces that allows reagentless in-place regeneration of the surface. The technology grafts thermoresponsive and nonspecific adhesion minimizing polymer nanolayer brush coatings from the prefilter media. These polymer nanolayer brush architectures can be triggered to contract and expand to generate a "pushing-off" force by the simple application of modestly thermocycled (i.e. cycling from ambient cabin temperature to 40 C) air streams. The nonspecific adhesion-minimizing properties of the coatings do not allow the particulate foulants to adhere strongly to the filter media, and thermocycled air streams applied to the media allow easy detachment and in-place regeneration of the media with minimal impact in system downtime or astronaut involvement in overseeing the process.

Fungal spore concentrations in two haematopoietic stem cell transplantation (HSCT) units containing distinct air control systems.

PubMed

Brun, C P; Miron, D; Silla, L M R; Pasqualotto, A C

2013-04-01

Invasive fungal diseases have emerged as important causes of morbidity and mortality in haematological patients. In this study air samples were collected in two haematopoietic stem cell transplantation (HSCT) units, in which distinct air-control systems were in place. In hospital 1 no high-efficiency particulate air (HEPA) filter was available whereas in hospital 2 HSCT rooms were equipped with HEPA filters, with positive air pressure in relation to the corridor. A total of 117 samples from rooms, toilets and corridors were obtained during December 2009 to January 2011, using a six-stage Andersen sampler. In both hospitals, the concentration of potentially pathogenic fungi in the air was reduced in patients' rooms compared to corridors (P < 0·0001). Despite the presence of a HEPA filter in hospital 2, rooms in both hospitals showed similar concentrations of potentially pathogenic fungi (P = 0·714). These findings may be explained by the implementation of additional protective measures in hospital 1, emphasizing the importance of such measures in protected environments.

Wood dust particle and mass concentrations and filtration efficiency in sanding of wood materials.

PubMed

Welling, Irma; Lehtimäki, Matti; Rautio, Sari; Lähde, Tero; Enbom, Seppo; Hynynen, Pasi; Hämeri, Kaarle

2009-02-01

The importance of fine particles has become apparent as the knowledge of their effects on health has increased. Fine particle concentrations have been published for outside air, plasma arc cutting, welding, and grinding, but little data exists for the woodworking industry. Sanding was evaluated as the producer of the woodworking industry's finest particles, and was selected as the target study. The number of dust particles in different particle size classes and the mass concentrations were measured in the following environments: workplace air during sanding in plywood production and in the inlet and return air; in the dust emission chamber; and in filter testing. The numbers of fine particles were low, less than 10(4) particles/cm(3) (10(7) particles/L). They were much lower than typical number concentrations near 10(6) particles/cm(3) measured in plasma arc cutting, grinding, and welding. Ultrafine particles in the size class less than 100 nm were found during sanding of MDF (medium density fiberboard) sheets. When the cleaned air is returned to the working areas, the dust content in extraction systems must be monitored continuously. One way to monitor the dust content in the return air is to use an after-filter and measure pressure drop across the filter to indicate leaks in the air-cleaning system. The best after-filtration materials provided a clear increase in pressure drop across the filter in the loading of the filter. The best after-filtration materials proved to be quite effective also for fine particles. The best mass removal efficiencies for fine particles around 0.3 mum were over 80% for some filter materials loaded with sanding wood dust.

Washable antimicrobial polyester/aluminum air filter with a high capture efficiency and low pressure drop.

PubMed

Choi, Dong Yun; Heo, Ki Joon; Kang, Juhee; An, Eun Jeong; Jung, Soo-Ho; Lee, Byung Uk; Lee, Hye Moon; Jung, Jae Hee

2018-06-05

Here, we introduce a reusable bifunctional polyester/aluminum (PET/Al) air filter for the high efficiency simultaneous capture and inactivation of airborne microorganisms. Both bacteria of Escherichia coli and Staphylococcus epidermidis were collected on the PET/Al filter with a high efficiency rate (∼99.99%) via the electrostatic interactions between the charged bacteria and fibers without sacrificing pressure drop. The PET/Al filter experienced a pressure drop approximately 10 times lower per thickness compared with a commercial high-efficiency particulate air filter. As the Al nanograins grew on the fibers, the antimicrobial activity against airborne E. coli and S. epidermidis improved to ∼94.8% and ∼96.9%, respectively, due to the reinforced hydrophobicity and surface roughness of the filter. Moreover, the capture and antimicrobial performances were stably maintained during a cyclic washing test of the PET/Al filter, indicative of its reusability. The PET/Al filter shows great potential for use in energy-efficient bioaerosol control systems suitable for indoor environments. Copyright © 2018 Elsevier B.V. All rights reserved.

Quick-change filter cartridge

DOEpatents

Rodgers, John C.; McFarland, Andrew R.; Ortiz, Carlos A.

1995-01-01

A quick-change filter cartridge. In sampling systems for measurement of airborne materials, a filter element is introduced into the sampled airstream such that the aerosol constituents are removed and deposited on the filter. Fragile sampling media often require support in order to prevent rupture during sampling, and careful mounting and sealing to prevent misalignment, tearing, or creasing which would allow the sampled air to bypass the filter. Additionally, handling of filter elements may introduce cross-contamination or exposure of operators to toxic materials. Moreover, it is desirable to enable the preloading of filter media into quick-change cartridges in clean laboratory environments, thereby simplifying and expediting the filter-changing process in the field. The quick-change filter cartridge of the present invention permits the application of a variety of filter media in many types of instruments and may also be used in automated systems. The cartridge includes a base through which a vacuum can be applied to draw air through the filter medium which is located on a porous filter support and held there by means of a cap which forms an airtight seal with the base. The base is also adapted for receiving absorbing media so that both particulates and gas-phase samples may be trapped for investigation, the latter downstream of the aerosol filter.

Evaluation of a Shaker Dust Collector for Use in a Recirculating Ventilation System

PubMed Central

Sawvel, Russell A.; Park, Jae Hong; Anthony, T. Renée

2016-01-01

General ventilation with recirculated air may be cost-effective to control the concentration of low-toxicity, contaminants in workplaces with diffuse, dusty operations, such as in agriculture. Such systems are, however, rarely adopted with little evidence showing improved air quality and ability to operate under harsh conditions. The goal of this work was to examine the initial and long-term performance of a fabric-filter shaker dust collector (SDC) in laboratory tests and as deployed within a recirculating ventilation system in an agricultural building. In laboratory tests, collection efficiency and pressure drop were tracked over several filter loading cycles, and the recovery of filter capacity (pressure drop) from filter shaking was examined. Collection efficiencies of particles larger than 5 μm was high (>95%) even when the filter was pristine, showing effective collection of large particles that dominate inhalable concentrations typical of agricultural dusts. For respirable-sized particles, collection efficiencies were low when the filter was pristine (e.g., 27% for 1 μm) but much higher when a dust cake developed on the filter (>99% for all size particles), even after shaking (e.g., 90% for 1 μm). The first shake of a filter was observed to recovery a substantial fraction of filter capacity, with subsequent shakes providing little benefit. In field tests, the SDC performed effectively over a period of three months in winter when incorporated in a recirculating ventilation system of a swine farrowing room. Trends in collection efficiency and pressure drop with loading were similar to those observed in the laboratory with overall collection efficiencies high (>80%) when pressure drop exceeded 230 Pa, or 23% of the maximum loading recommended by the manufacturer. This work shows that the SDC can function effectively over the harsh winter in swine rearing operations. Together with findings of improved air quality in the farrowing room reported in a companion manuscript, this article provides evidence that an SDC represents a cost-effective solution to improve air quality in agricultural settings. PMID:25955507

Using liquid desiccant as a regenerable filter for capturing and deactivating contaminants

DOEpatents

Slayzak, Steven J.; Anderson, Ren S.; Judkoff, Ronald D.; Blake, Daniel M.; Vinzant, Todd B.; Ryan, Joseph P.

2007-12-11

A method, and systems for implementing such method, for purifying and conditioning air of weaponized contaminants. The method includes wetting a filter packing media with a salt-based liquid desiccant, such as water with a high concentration of lithium chloride. Air is passed through the wetted filter packing media and the contaminants in are captured with the liquid desiccant while the liquid desiccant dehumidifies the air. The captured contaminants are then deactivated in the liquid desiccant, which may include heating the liquid desiccant. The liquid desiccant is regenerated by applying heat to the liquid desiccant and then removing moisture. The method includes repeating the wetting with the regenerated liquid desiccant which provides a regenerable filtering process that captures and deactivates contaminants on an ongoing basis while also conditioning the air. The method may include filtration effectiveness enhancement by electrostatic or inertial means.

Development of an in-line filter to prevent intrusion of NO2 toxic vapors into A/C systems

NASA Technical Reports Server (NTRS)

Meneghelli, Barry; Mcnulty, R. J.; Springer, Mike; Lueck, Dale E.

1995-01-01

The hypergolic propellant nitrogen tetroxide (N2O4 or NTO) is routinely used in spacecraft launched at Kennedy Space Center (KSC) and Cape Canaveral Air Station (CCAS). In the case of a catastrophic failure of the spacecraft, there would be a release of the unspent propellant in the form of a toxic cloud. Inhalation of this material at downwind concentrations which may be as high as 20 parts per million (ppm) for 30 minutes in duration, may produce irritation to the eyes, nose and respiratory tract. Studies at both KSC and CCAS have shown that the indoor concentrations of N2O4 during a toxic release may range from 1 to 15 ppm and depend on the air change rate (ACR) for a particular building and whether or not the air conditioning (A/C) system has been shut down or left in an operating mode. This project was initiated in order to assess how current A/C systems could be easily modified to prevent personnel from being exposed to toxic vapors. A sample system has been constructed to test the ability of several types of filter material to capture the N2O4 vapors prior to their infiltration into the A/C system. Test results will be presented which compare the efficiencies of standard A/C filters, water wash systems, and chemically impregnated filter material in taking toxic vapors out of the incoming air stream.

ENVIRONMENTAL TECHNOLOGY VERIFICATION, TEST REPORT OF CONTROL OF BIOAEROSOLS IN HVAC SYSTEMS, FILTRATION GROUP, AEROSTAR "C-SERIES" POLYESTER PANEL FILTER

EPA Science Inventory

The Environmental Technology Verification report discusses the technology and performance of the AeroStar "C-Series" Polyester Panel Filter air filter for dust and bioaerosol filtration manufactured by Filtration Group. The pressure drop across the filter was 126 Pa clean and 267...

RadNet Air Data From Honolulu, HI

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RadNet Air Data From Yaphank, NY

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RadNet Air Data From Anaheim, CA

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RadNet Air Data From Riverside, CA

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RadNet Air Data From Detroit, MI

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RadNet Air Data From Wichita, KS

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RadNet Air Data From Columbia, SC

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RadNet Air Data From Milwaukee, WI

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RadNet Air Data From Richmond, VA

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RadNet Air Data From Tulsa, OK

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RadNet Air Data From Aurora, IL

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RadNet Air Data From Hartford, CT

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RadNet Air Data From Charleston, WV

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RadNet Air Data From Shawano, WI

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RadNet Air Data From Harlingen, TX

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RadNet Air Data From Springfield, MO

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RadNet Air Data From Olympia, WA

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RadNet Air Data From Memphis, TN

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RadNet Air Data From Lubbock, TX

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RadNet Air Data From Sacramento, CA

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RadNet Air Data From Lockport, NY

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RadNet Air Data From Jackson, MS

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RadNet Air Data From Seattle, WA

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RadNet Air Data From Pittsburgh, PA

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RadNet Air Data From Madison, WI

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RadNet Air Data From Ellensburg, WA

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RadNet Air Data From Harrisonburg, VA

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RadNet Air Data From Bismarck, ND

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RadNet Air Data From Denver, CO

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RadNet Air Data From Charlotte, NC

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RadNet Air Data From Lexington, KY

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RadNet Air Data From Casper, WY

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RadNet Air Data From Eureka, CA

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RadNet Air Data From Lincoln, NE

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RadNet Air Data From Orlando, FL

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RadNet Air Data From Mobile, AL

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RadNet Air Data From Spokane, WA

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RadNet Air Data From Atlanta, GA

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RadNet Air Data From Greensboro, NC

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RadNet Air Data From Chicago, IL

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RadNet Air Data From Worcester, MA

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RadNet Air Data From Austin, TX

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Ultrasmall multi-channel resonant-tunneling filter using mode gap of width-tuned photonic-crystal waveguide.

PubMed

Shinya, Akihiko; Mitsugi, Satoshi; Kuramochi, Eiichi; Notomi, Masaya

2005-05-30

We have devised an ultra-small multi-channel drop filter based on a two-port resonant tunneling system in a two-dimensional photonic crystal with a triangular air-hole lattice. This filter does not require careful consideration of the interference process to achieve a high dropping efficiency. First we develop three-port systems based on a two-port resonant tunneling filter. Next we devise a multi-port channel drop filter by cascading these three-port systems. In this paper, we demonstrate a ten-channel drop filter with an 18 mum device size by 2D-FDTD calculation, and a three-port resonant tunneling filter with 65+/- 20 % dropping efficiency by experiment.

Determination of polybrominated diphenyl ethers (PBDEs) in dust samples collected in air conditioning filters of different usage - method development.

PubMed

Śmiełowska, M; Zabiegała, B

2018-06-19

This study presents the results of studies aimed at the development of an analytical procedure for separation, identification, and determination of PBDEs compounds in dust samples collected from automotive cabin air filters and samples collected from filters installed as part of the air purification system in academic facilities. Ultrasound-assisted dispersive solid phase extraction (UA-dSPE) was found to perform better in terms of extract purification than the conventional SPE technique. GC-EIMS was used for final determination of analytes. The concentrations of PBDEs in car filters ranged from < LOD to 688 ng/g while from < LOD to 247 ng/g in dust from air conditioning filters. BDE-47 and BDE-100 were reported the dominating congeners. The estimated exposure to PBDEs via ingestion of dust from car filters varied from 0.00022 to 0.012 ng/day in toddlers and from 0.000036 to 0.0029 ng/day in adults; dust from air conditioning filters: from 0.017 to 0.25 ng/day in toddlers and from 0.0029 to 0.042 ng/day. In addition, an attempt was made at extracting PBDEs from a dust samples using the matrix solid-phase dispersion (MSPD) technique as a promising alternative to conventional SPE separations. Copyright © 2018 Elsevier B.V. All rights reserved.

Guide to Air Cleaners in the Home

MedlinePlus

... In-duct Particle Removal Flat or panel air filters Pleated or extended surface filters In-duct Gaseous Pollutant Removal In-duct Pollutant ... can remove particles from the air — mechanical air filters and electronic air cleaners. Mechanical air filters remove ...

Integration of air separation membrane and coalescing filter for use on an inlet air system of an engine

DOEpatents

Moncelle, Michael E.

2003-01-01

An intake air separation system suitable for combustion air of an internal combustion engine. An air separation device of the system includes a plurality of fibers, each fiber having a tube with a permeation barrier layer on the outer surface thereof and a coalescing layer on the inner surface thereof, to restrict fluid droplets from contacting the permeation barrier layer.

Interior Landscape Plants for Indoor Air Pollution Abatement

NASA Technical Reports Server (NTRS)

Wolverton, B. C.; Johnson, Anne; Bounds, Keith

1989-01-01

In this study, the leaves, roots, soil, and associated microorganisms of plants have been evaluated as a possible means of reducing indoor air pollutants. Additionally, a novel approach of using plant systems for removing high concentrations of indoor air pollutants such as cigarette smoke, organic solvents, and possibly radon has been designed from this work. This air filter design combines plants with an activated carbon filter. The rationale for this design, which evolved from wastewater treatment studies, is based on moving large volumes of contaminated air through an activated carbon bed where smoke, organic chemicals, pathogenic microorganisms (if present), and possibly radon are absorbed by the carbon filter. Plant roots and their associated microorganisms then destroy the pathogenic viruses, bacteria, and the organic chemicals, eventually converting all of these air pollutants into new plant tissue. It is believed that the decayed radon products would be taken up the plant roots and retained in the plant tissue.

Integrated photocatalytic filtration array for indoor air quality control.

PubMed

Denny, Frans; Permana, Eric; Scott, Jason; Wang, Jing; Pui, David Y H; Amal, Rose

2010-07-15

Photocatalytic and filtration technologies were integrated to develop a hybrid system capable of removing and oxidizing organic pollutants from an air stream. A fluidized bed aerosol generator (FBAG) was adapted to prepare TiO(2)-loaded ventilation filters for the photodegradation of gas phase ethanol. Compared to a manually loaded filter, the ethanol photodegradation rate constant for the FBAG coated filter increased by 361%. Additionally, the presence of the photogenerated intermediate product, acetaldehyde, was reduced and the time for mineralization to CO(2) was accelerated. These improvements were attributed to the FBAG system providing a more uniform distribution of TiO(2) particles across the filter surface leading to greater accessibility by the UV light. A dual-UV-lamp system, as opposed to a single-lamp system, enhanced photocatalytic filter performance demonstrating the importance of high light irradiance and light distribution across the filter surface. Substituting the blacklight blue lamps with a UV-light-emitting-diode (UV-LED) array led to further improvement as well as suppressed the electrical energy per order (EE/O) by a factor of 6. These improvements derived from the more uniform distribution of light irradiance as well as the higher efficiency of UV-LEDs in converting electrical energy to photons.

RadNet Air Data From San Juan, PR

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RadNet Air Data From Grand Rapids, MI

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RadNet Air Data From Corpus Christi, TX

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RadNet Air Data From Little Rock, AR

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RadNet Air Data From Des Moines, IA

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RadNet Air Data From Fort Madison, IA

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RadNet Air Data From Fort Wayne, IN

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RadNet Air Data From Navajo Lake, NM

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RadNet Air Data From Las Vegas, NV

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RadNet Air Data From St. George, UT

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RadNet Air Data From Jefferson City, MO

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RadNet Air Data From Fort Worth, TX

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RadNet Air Data From Kansas City, KS

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RadNet Air Data From San Angelo, TX

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RadNet Air Data From San Francisco, CA

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RadNet Air Data From Oklahoma City, OK

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RadNet Air Data From San Bernardino, CA

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RadNet Air Data From Idaho Falls, ID

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RadNet Air Data From Los Angeles, CA

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RadNet Air Data From El Paso, TX

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RadNet Air Data From Grand Junction, CO

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RadNet Air Data From St. Paul, MN

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RadNet Air Data From Virginia Beach, VA

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RadNet Air Data From La Crosse, WI

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RadNet Air Data From San Diego, CA

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RadNet Air Data From San Jose, CA

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RadNet Air Data From San Antonio, TX

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RadNet Air Data From Rapid City, SD

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RadNet Air Data From Dodge City, KS

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RadNet Air Data From Colorado Springs, CO

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RadNet Air Data From St. Louis, MO

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RadNet Air Data From Bay City, MI

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RadNet Air Data From Mason City, IA

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RadNet Air Data From Fort Smith, AR

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Air Sampling Filter

NASA Technical Reports Server (NTRS)

1980-01-01

General Metal Works' Accu-Vol is a high-volume air sampling system used by many government agencies to monitor air quality for pollution control purposes. Procedure prevents possible test-invalidating contamination from materials other than particulate pollutants, caused by manual handling or penetration of windblown matter during transit, a cassette was developed in which the filter is sealed within a metal frame and protected in transit by a snap-on aluminum cover, thus handled only under clean conditions in the laboratory.

A comparison of two nano-sized particle air filtration tests in the diameter range of 10 to 400 nanometers

NASA Astrophysics Data System (ADS)

Japuntich, Daniel A.; Franklin, Luke M.; Pui, David Y.; Kuehn, Thomas H.; Kim, Seong Chan; Viner, Andrew S.

2007-01-01

Two different air filter test methodologies are discussed and compared for challenges in the nano-sized particle range of 10-400 nm. Included in the discussion are test procedure development, factors affecting variability and comparisons between results from the tests. One test system which gives a discrete penetration for a given particle size is the TSI 8160 Automated Filter tester (updated and commercially available now as the TSI 3160) manufactured by the TSI, Inc., Shoreview, MN. Another filter test system was developed utilizing a Scanning Mobility Particle Sizer (SMPS) to sample the particle size distributions downstream and upstream of an air filter to obtain a continuous percent filter penetration versus particle size curve. Filtration test results are shown for fiberglass filter paper of intermediate filtration efficiency. Test variables affecting the results of the TSI 8160 for NaCl and dioctyl phthalate (DOP) particles are discussed, including condensation particle counter stability and the sizing of the selected particle challenges. Filter testing using a TSI 3936 SMPS sampling upstream and downstream of a filter is also shown with a discussion of test variables and the need for proper SMPS volume purging and filter penetration correction procedure. For both tests, the penetration versus particle size curves for the filter media studied follow the theoretical Brownian capture model of decreasing penetration with decreasing particle diameter down to 10 nm with no deviation. From these findings, the authors can say with reasonable confidence that there is no evidence of particle thermal rebound in the size range.

Energy Systems Integration Facility Office Space | Energy Systems

Science.gov Websites

unit has a design capacity of 24,000 cfm (with a minimum outside air of 6,500 cfm) and consists of a pre-filter, heating coil, fan section, cooling coil, and final filter. The office space also has

30 CFR 57.22210 - In-line filters (I-C mines).

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false In-line filters (I-C mines). 57.22210 Section... Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22210 In-line filters (I-C mines). Filters or separators shall be installed on air-lift fan systems to prevent explosive concentrations of...

30 CFR 57.22210 - In-line filters (I-C mines).

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false In-line filters (I-C mines). 57.22210 Section... Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22210 In-line filters (I-C mines). Filters or separators shall be installed on air-lift fan systems to prevent explosive concentrations of...

30 CFR 57.22210 - In-line filters (I-C mines).

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false In-line filters (I-C mines). 57.22210 Section... Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22210 In-line filters (I-C mines). Filters or separators shall be installed on air-lift fan systems to prevent explosive concentrations of...

30 CFR 57.22210 - In-line filters (I-C mines).

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false In-line filters (I-C mines). 57.22210 Section... Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22210 In-line filters (I-C mines). Filters or separators shall be installed on air-lift fan systems to prevent explosive concentrations of...

30 CFR 57.22210 - In-line filters (I-C mines).

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false In-line filters (I-C mines). 57.22210 Section... Standards for Methane in Metal and Nonmetal Mines Ventilation § 57.22210 In-line filters (I-C mines). Filters or separators shall be installed on air-lift fan systems to prevent explosive concentrations of...

ENVIRONMENTAL TECHNOLOGY VERIFICATION, TEST REPORT OF CONTROL OF BIOAEROSOLS IN HVAC SYSTEMS, FILTRATION GROUP, AEROSTAR FP-98 MINIPLEAT V-BLANK FILTER

EPA Science Inventory

The Environmental Technology Verification report discusses the technology and performance of the AeroStar FP-98 Minipleat V-Bank Filter air filter for dust and bioaerosol filtration manufactured by Filtration Group. The pressure drop across the filter was 137 Pa clean and 348 Pa ...

EFFECT OF VENTILATION SYSTEMS AND AIR FILTERS ON DECAY RATES OF PARTICLES PRODUCED BY INDOOR SOURCES IN AN OCCUPIED TOWNHOUSE

EPA Science Inventory

Several studies have shown the importance of particle losses in real homes due to deposition and filtration; however, none have quantitatively shown the impact of using a central forced air fan and in-duct filter on particle loss rates. In an attempt to provide such data, we me...

International Space Station (ISS) Bacterial Filter Elements (BFEs): Filter Efficiency and Pressure Drop Testing of Returned Units

NASA Technical Reports Server (NTRS)

Green, Robert D.; Agui, Juan H.; Vijayakumar, R.; Berger, Gordon M.; Perry, Jay L.

2017-01-01

The air quality control equipment aboard the International Space Station (ISS) and future deep space exploration vehicles provide the vital function of maintaining a clean cabin environment for the crew and the hardware. This becomes a serious challenge in pressurized space compartments since no outside air ventilation is possible, and a larger particulate load is imposed on the filtration system due to lack of sedimentation. The ISS Environmental Control and Life Support (ECLS) system architecture in the U.S. Segment uses a distributed particulate filtration approach consisting of traditional High-Efficiency Particulate Air (HEPA) filters deployed at multiple locations in each U.S. Seg-ment module; these filters are referred to as Bacterial Filter Elements, or BFEs. In our previous work, we presented results of efficiency and pressure drop measurements for a sample set of two returned BFEs with a service life of 2.5 years. In this follow-on work, we present similar efficiency, pressure drop, and leak tests results for a larger sample set of six returned BFEs. The results of this work can aid the ISS Program in managing BFE logistics inventory through the stations planned lifetime as well as provide insight for managing filter element logistics for future exploration missions. These results also can provide meaningful guidance for particulate filter designs under consideration for future deep space exploration missions.

Filter Efficiency and Pressure Testing of Returned ISS Bacterial Filter Elements (BFEs)

NASA Technical Reports Server (NTRS)

Green, Robert D.; Agui, Juan H.; Berger, Gordon M.; Vijayakumar, R.; Perry, Jay L.

2017-01-01

The air quality control equipment aboard the International Space Station (ISS) and future deep space exploration vehicles provide the vital function of maintaining a clean cabin environment for the crew and the hardware. This becomes a serious challenge in pressurized space compartments since no outside air ventilation is possible, and a larger particulate load is imposed on the filtration system due to lack of sedimentation. The ISS Environmental Control and Life Support (ECLS) system architecture in the U.S. Segment uses a distributed particulate filtration approach consisting of traditional High-Efficiency Particulate Air (HEPA) filters deployed at multiple locations in each U.S. Seg-ment module; these filters are referred to as Bacterial Filter Elements, or BFEs. In our previous work, we presented results of efficiency and pressure drop measurements for a sample set of two returned BFEs with a service life of 2.5 years. In this follow-on work, we present similar efficiency, pressure drop, and leak tests results for a larger sample set of six returned BFEs. The results of this work can aid the ISS Program in managing BFE logistics inventory through the stations planned lifetime as well as provide insight for managing filter element logistics for future exploration missions. These results also can provide meaningful guidance for particulate filter designs under consideration for future deep space exploration missions.

RadNet Air Data From Salt Lake City, UT

EPA Pesticide Factsheets

This page presents radiation air monitoring and air filter analysis data for Salt Lake City, UT from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

RadNet Air Data From New York City, NY

EPA Pesticide Factsheets

This page presents radiation air monitoring and air filter analysis data for New York City, NY from EPA's RadNet system. RadNet is a nationwide network of monitoring stations that measure radiation in air, drinking water and precipitation.

Construction, Testing, and Analysis of Radon Mitigation System

NASA Astrophysics Data System (ADS)

Jardin, Dan; Schnee, Richard; CDMS Collaboration

2011-10-01

The search for dark matter or other rare events such as neutrinoless double-beta decay is difficult in the presence of background radiation such as the alpha and beta emissions from the 222Rn decay chain. In order to reduce the radioactive background from Rn-daughters, an ultra-low radon clean room is being built at Syracuse University. A vacuum-swing adsorption system is used to mitigate the radon. Air flows through one of two tanks filled with charcoal that the radon adsorbs to, allowing the filtered air to pass into the clean room. Computer-controlled valves direct the airflow so that one tank filters the air while the other tank is purged of radon by circulating a small fraction of the cleaned airflow back through the tank at low pressure. The durations, pressures, and flow rates of each stage of building pressure, filtering, releasing pressure, and purging in the tanks are optimized in order to maximize the reduction of radon from the air. Professor.

Ultrafine particle removal by residential heating, ventilating, and air-conditioning filters.

PubMed

Stephens, B; Siegel, J A

2013-12-01

This work uses an in situ filter test method to measure the size-resolved removal efficiency of indoor-generated ultrafine particles (approximately 7-100 nm) for six new commercially available filters installed in a recirculating heating, ventilating, and air-conditioning (HVAC) system in an unoccupied test house. The fibrous HVAC filters were previously rated by the manufacturers according to ASHRAE Standard 52.2 and ranged from shallow (2.5 cm) fiberglass panel filters (MERV 4) to deep-bed (12.7 cm) electrostatically charged synthetic media filters (MERV 16). Measured removal efficiency ranged from 0 to 10% for most ultrafine particles (UFP) sizes with the lowest rated filters (MERV 4 and 6) to 60-80% for most UFP sizes with the highest rated filter (MERV 16). The deeper bed filters generally achieved higher removal efficiencies than the panel filters, while maintaining a low pressure drop and higher airflow rate in the operating HVAC system. Assuming constant efficiency, a modeling effort using these measured values for new filters and other inputs from real buildings shows that MERV 13-16 filters could reduce the indoor proportion of outdoor UFPs (in the absence of indoor sources) by as much as a factor of 2-3 in a typical single-family residence relative to the lowest efficiency filters, depending in part on particle size. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

International Space Station (ISS) Bacterial Filter Elements (BFEs): Filter Efficiency and Pressure Testing of Returned Units

NASA Technical Reports Server (NTRS)

Green, Robert D.; Agui, Juan H.; Vijayakumar, R.

2017-01-01

The air revitalization system aboard the International Space Station (ISS) provides the vital function of maintaining a clean cabin environment for the crew and the hardware. This becomes a serious challenge in pressurized space compartments since no outside air ventilation is possible, and a larger particulate load is imposed on the filtration system due to lack of sedimentation due to the microgravity environment in Low Earth Orbit (LEO). The ISS Environmental Control and Life Support (ECLS) system architecture in the U.S. Segment uses a distributed particulate filtration approach consisting of traditional High-Efficiency Particulate Adsorption (HEPA) media filters deployed at multiple locations in each U.S. Segment module; these filters are referred to as Bacterial Filter Elements, or BFEs. These filters see a replacement interval, as part of maintenance, of 2-5 years dependent on location in the ISS. In this work, we present particulate removal efficiency, pressure drop, and leak test results for a sample set of 8 BFEs returned from the ISS after filter replacement. The results can potentially be utilized by the ISS Program to ascertain whether the present replacement interval can be maintained or extended to balance the on-ground filter inventory with extension of the lifetime of ISS beyond 2024. These results can also provide meaningful guidance for particulate filter designs under consideration for future deep space exploration missions.

DNA accumulation on ventilation system filters in university buildings in Singapore

PubMed Central

Luhung, Irvan; Wu, Yan; Xu, Siyu; Yamamoto, Naomichi; Nazaroff, William W.

2017-01-01

Introduction Biological particles deposit on air handling system filters as they process air. This study reports and interprets abundance and diversity information regarding biomass accumulation on ordinarily used filters acquired from several locations in a university environment. Methods DNA-based analysis was applied both to quantify (via DNA fluorometry and qPCR) and to characterize (via high-throughput sequencing) the microbial material on filters, which mainly processed recirculated indoor air. Results were interpreted in relation to building occupancy and ventilation system operational parameters. Results Based on accumulated biomass, average DNA concentrations per AHU filter surface area across nine indoor locations after twelve weeks of filter use were in the respective ranges 1.1 to 41 ng per cm2 for total DNA, 0.02 to 3.3 ng per cm2 for bacterial DNA and 0.2 to 2.0 ng DNA per cm2 for fungal DNA. The most abundant genera detected on the AHU filter samples were Clostridium, Streptophyta, Bacillus, Acinetobacter and Ktedonobacter for bacteria and Aspergillus, Cladosporium, Nigrospora, Rigidoporus and Lentinus for fungi. Conditional indoor airborne DNA concentrations (median (range)) were estimated to be 13 (2.6–107) pg/m3 for total DNA, 0.4 (0.05–8.4) pg/m3 for bacterial DNA and 2.3 (1.0–5.1) pg/m3 for fungal DNA. Conclusion Conditional airborne concentrations and the relative abundances of selected groups of genera correlate well with occupancy level. Bacterial DNA was found to be more responsive than fungal DNA to differences in occupancy level and indoor environmental conditions. PMID:29023520

The impact of recirculation, ventilation and filters on secondary organic aerosols generated by indoor chemistry

NASA Astrophysics Data System (ADS)

Fadeyi, M. O.; Weschler, C. J.; Tham, K. W.

This study examined the impact of recirculation rates (7 and 14 h -1), ventilation rates (1 and 2 h -1), and filtration on secondary organic aerosols (SOAs) generated by ozone of outdoor origin reacting with limonene of indoor origin. Experiments were conducted within a recirculating air handling system that serviced an unoccupied, 236 m 3 environmental chamber configured to simulate an office; either no filter, a new filter or a used filter was located downstream of where outdoor air mixed with return air. For otherwise comparable conditions, the SOA number and mass concentrations at a recirculation rate of 14 h -1 were significantly smaller than at a recirculation rate of 7 h -1. This was due primarily to lower ozone concentrations, resulting from increased surface removal, at the higher recirculation rate. Increased ventilation increased outdoor-to-indoor transport of ozone, but this was more than offset by the increased dilution of SOA derived from ozone-initiated chemistry. The presence of a particle filter (new or used) strikingly lowered SOA number and mass concentrations compared with conditions when no filter was present. Even though the particle filter in this study had only 35% single-pass removal efficiency for 100 nm particles, filtration efficiency was greatly amplified by recirculation. SOA particle levels were reduced to an even greater extent when an activated carbon filter was in the system, due to ozone removal by the carbon filter. These findings improve our understanding of the influence of commonly employed energy saving procedures on occupant exposures to ozone and ozone-derived SOA.

[Microbial air purity in hospitals. Operating theatres with air conditioning system].

PubMed

Krogulski, Adam; Szczotko, Maciej

2010-01-01

The aim of this study was to show the influence of air conditioning control for microbial contamination of air inside the operating theatres equipped with correctly working air-conditioning system. This work was based on the results of bacteria and fungi concentration in hospital air obtained since 2001. Assays of microbial air purity conducted on atmospheric air in parallel with indoor air demonstrated that air filters applied in air-conditioning systems worked correctly in every case. To show the problem of fluctuation of bacteria concentration more precisely, every sequences of single results from successive measure series were examined independently.

Molecular comparison of the sampling efficiency of four types of airborne bacterial samplers.

PubMed

Li, Kejun

2011-11-15

In the present study, indoor and outdoor air samples were collected using four types of air samplers often used for airborne bacterial sampling. These air samplers included two solid impactors (BioStage and RCS), one liquid impinger (BioSampler), and one filter sampler with two kinds of filters (a gelatin and a cellulose acetate filter). The collected air samples were further processed to analyze the diversity and abundance of culturable bacteria and total bacteria through standard culture techniques, denaturing gradient gel electrophoresis (DGGE) fingerprinting and quantitative polymerase chain reaction (qPCR) analysis. The DGGE analysis indicated that the air samples collected using the BioStage and RCS samplers have higher culturable bacterial diversity, whereas the samples collected using the BioSampler and the cellulose acetate filter sampler have higher total bacterial diversity. To obtain more information on the sampled bacteria, some gel bands were excised and sequenced. In terms of sampling efficiency, results from the qPCR tests indicated that the collected total bacterial concentration was higher in samples collected using the BioSampler and the cellulose acetate filter sampler. In conclusion, the sampling bias and efficiency of four kinds of air sampling systems were compared in the present study and the two solid impactors were concluded to be comparatively efficient for culturable bacterial sampling, whereas the liquid impactor and the cellulose acetate filter sampler were efficient for total bacterial sampling. Copyright © 2011 Elsevier B.V. All rights reserved.

Proceedings of the 21st DOE/NRC Nuclear Air Cleaning Conference; Sessions 1--8

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

First, M.W.

1991-02-01

Separate abstracts have been prepared for the papers presented at the meeting on nuclear facility air cleaning technology in the following specific areas of interest: air cleaning technologies for the management and disposal of radioactive wastes; Canadian waste management program; radiological health effects models for nuclear power plant accident consequence analysis; filter testing; US standard codes on nuclear air and gas treatment; European community nuclear codes and standards; chemical processing off-gas cleaning; incineration and vitrification; adsorbents; nuclear codes and standards; mathematical modeling techniques; filter technology; safety; containment system venting; and nuclear air cleaning programs around the world. (MB)

ENVIRONMENTAL TECHNOLOGY VERIFICATION, TEST REPORT OF CONTROL OF BIOAEROSOLS IN HVAC SYSTEMS: TRI-DIM FILTER CORP. PREDATOR II MODEL 8VADTP123C23

EPA Science Inventory

The Environmental Technology Verification report discusses the technology and performance of the Predator II, Model 8VADTP123C23CC000 air filter for dust and bioaerosol filtration manufactured by Tri-Dim Filter Corporation. The pressure drop across the filter was 138 Pa clean and...

Development of an Indexing Media Filtration System for Long Duration Space Missions

NASA Technical Reports Server (NTRS)

Agui, Juan H.; Vijayakumar, R.

2013-01-01

The effective maintenance of air quality aboard spacecraft cabins will be vital to future human exploration missions. A key component will be the air cleaning filtration system which will need to remove a broad size range of particles derived from multiple biological and material sources. In addition, during surface missions any extraterrestrial planetary dust, including dust generated by near-by ISRU equipment, which is tracked into the habitat will also need to be managed by the filtration system inside the pressurized habitat compartments. An indexing media filter system is being developed to meet the demand for long-duration missions that will result in dramatic increases in filter service life and loading capacity, and will require minimal crew involvement. The filtration system consists of three stages: an inertial impactor stage, an indexing media stage, and a high-efficiency filter stage, packaged in a stacked modular cartridge configuration. Each stage will target a specific range of particle sizes that optimize the filtration and regeneration performance of the system. An 1/8th scale and full-scale prototype of the filter system have been fabricated and have been tested in the laboratory and reduced gravity environments that simulate conditions on spacecrafts, landers and habitats. Results from recent laboratory and reduce-gravity flight tests data will be presented. The features of the new filter system may also benefit other closed systems, such as submarines, and remote location terrestrial installations where servicing and replacement of filter units is not practical.

[Sick building syndrome and HVAC system: MVOC from air filters].

PubMed

Schleibinger, H W; Wurm, D; Möritz, M; Böck, R; Rüden, H

1997-08-01

Growth and emissions of volatile metabolites of microorganisms on air filters are suspected to contribute to health complaints in ventilated rooms. To prove the microbiological production of volatile organic compounds (MVOC), concentrations of aldehydes and ketones were determined in two large HVAC systems. The in situ derivated aldehydes and ketones (as 2,4-dinitrophenyl-hydrazones) were analysed by HPLC and UV detection. The detection limit of each compound was 1 ppb (margin of error < 10%). Field measurements were carried out before and after the prefilters and the main filters, respectively, to investigate whether aldehydes and ketones increase in concentration after filters of HVAC systems. First results show that the compounds formaldehyde, acetaldehyde and acetone could be detected before and after the filters. The concentrations of these VOC after the filters were significantly increased--as a mean over twenty measurements--, especially as far as filters made of glass fibre are concerned. However the found concentrations were low and mostly comparable to outdoor findings. In simultaneous laboratory experiments pieces of used filter material of one HVAC system and unused filter pieces (for blank values) were examined in small incubation chambers to investigate the possible production of MVOC. For the incubation a temperature of 20 degrees C and a relative humidity of 95% was chosen. In these experiments an almost identical spectrum of compounds (formaldehyde and acetone) was found as in the field measurements. The concentrations of these compounds were higher in the chambers with the used filter pieces. The concentration of acetone ranged up to almost 12 mg/m3.--As our field experiments correspond with our laboratory experiments, we assume that the microbial production of volatile organic compounds in HVAC systems under operating conditions is possible.

Influence of ventilation and filtration on indoor particle concentrations in urban office buildings

NASA Astrophysics Data System (ADS)

Quang, Tran Ngoc; He, Congrong; Morawska, Lidia; Knibbs, Luke D.

2013-11-01

This study aimed to quantify the efficiency of deep bag and electrostatic filters, and assess the influence of ventilation systems using these filters on indoor fine (<2.5 μm) and ultrafine particle concentrations in commercial office buildings. Measurements and modelling were conducted for different indoor and outdoor particle source scenarios at three office buildings in Brisbane, Australia. Overall, the in-situ efficiency, measured for particles in size ranges 6-3000 nm, of the deep bag filters ranged from 26.3 to 46.9% for the three buildings, while the in-situ efficiency of the electrostatic filter in one building was 60.2%. The highest PN and PM2.5 concentrations in one of the office buildings (up to 131% and 31% higher than the other two buildings, respectively) were due to the proximity of the building's HVAC air intakes to a nearby bus-only roadway, as well as its higher outdoor ventilation rate. The lowest PN and PM2.5 concentrations (up to 57% and 24% lower than the other two buildings, respectively) were measured in a building that utilised both outdoor and mixing air filters in its HVAC system. Indoor PN concentrations were strongly influenced by outdoor levels and were significantly higher during rush-hours (up to 41%) and nucleation events (up to 57%), compared to working-hours, for all three buildings. This is the first time that the influence of new particle formation on indoor particle concentrations has been identified and quantified. A dynamic model for indoor PN concentration, which performed adequately in this study also revealed that using mixing/outdoor air filters can significantly reduce indoor particle concentration in buildings where indoor air was strongly influenced by outdoor particle levels. This work provides a scientific basis for the selection and location of appropriate filters and outdoor air intakes, during the design of new, or upgrade of existing, building HVAC systems. The results also serve to provide a better understanding of indoor particle dynamics and behaviours under different ventilation and particle source scenarios, and highlight effective methods to reduce exposure to particles in commercial office buildings.

Summary of efficiency testing of standard and high-capacity high-efficiency particulate air filters subjected to simulated tornado depressurization and explosive shock waves

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

Smith, P.R.; Gregory, W.S.

1985-04-01

Pressure transients in nuclear facility air cleaning systems can originate from natural phenomena such as tornadoes or from accident-induced explosive blast waves. This study was concerned with the effective efficiency of high-efficiency particulate air (HEPA) filters during pressure surges resulting from simulated tornado and explosion transients. The primary objective of the study was to examine filter efficiencies at pressure levels below the point of structural failure. Both standard and high-capacity 0.61-m by 0.61-m HEPA filters were evaluated, as were several 0.2-m by 0.2-m HEPA filters. For a particular manufacturer, the material release when subjected to tornado transients is the samemore » (per unit area) for both the 0.2-m by 0.2-m and the 0.61-m by 0.61-m filters. For tornado transients, the material release was on the order of micrograms per square meter. When subjecting clean HEPA filters to simulated tornado transients with aerosol entrained in the pressure pulse, all filters tested showed a degradation of filter efficiency. For explosive transients, the material release from preloaded high-capacity filters was as much as 340 g. When preloaded high-capacity filters were subjected to shock waves approximately 50% of the structural limit level, 1 to 2 mg of particulate was released.« less

40 CFR 91.407 - Engine inlet and exhaust systems.

Code of Federal Regulations, 2010 CFR

2010-07-01

.... (b) The air inlet filter system and exhaust muffler system combination used on the test engine must... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Engine inlet and exhaust systems. 91.407 Section 91.407 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS...

40 CFR 204.55-3 - Configuration identification.

Code of Federal Regulations, 2011 CFR

2011-07-01

... compressor stages. (3) Maximum pressure (psi). (4) Air intake system of compressor: (i) Number of filters; (ii) Type of filters. (5) The engine system: (i) Number of cylinders and configuration (L-6, V-8, V-12..., water cooled. (7) Fan: (i) Diameter; (ii) Maximum fan rpm. (8) The compressor enclosure: (i) Height...

40 CFR 204.55-3 - Configuration identification.

Code of Federal Regulations, 2013 CFR

2013-07-01

... compressor stages. (3) Maximum pressure (psi). (4) Air intake system of compressor: (i) Number of filters; (ii) Type of filters. (5) The engine system: (i) Number of cylinders and configuration (L-6, V-8, V-12..., water cooled. (7) Fan: (i) Diameter; (ii) Maximum fan rpm. (8) The compressor enclosure: (i) Height...

40 CFR 204.55-3 - Configuration identification.

Code of Federal Regulations, 2014 CFR

2014-07-01

... compressor stages. (3) Maximum pressure (psi). (4) Air intake system of compressor: (i) Number of filters; (ii) Type of filters. (5) The engine system: (i) Number of cylinders and configuration (L-6, V-8, V-12..., water cooled. (7) Fan: (i) Diameter; (ii) Maximum fan rpm. (8) The compressor enclosure: (i) Height...

40 CFR 204.55-3 - Configuration identification.

Code of Federal Regulations, 2012 CFR

2012-07-01

... compressor stages. (3) Maximum pressure (psi). (4) Air intake system of compressor: (i) Number of filters; (ii) Type of filters. (5) The engine system: (i) Number of cylinders and configuration (L-6, V-8, V-12..., water cooled. (7) Fan: (i) Diameter; (ii) Maximum fan rpm. (8) The compressor enclosure: (i) Height...

Research and Development for Off-Road Fuel Cell Applications U.S. Department of Energy Grant DE-FG36-04GO14303 - Final Report

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

Hicks, Michael; Erickson, Paul; Lawrence, Richard

Off-road concerns are related to the effects of shock and vibration and air quality on fuel cell power requirements. Mechanical stresses on differing material makeup and mass distribution within the system may render some components susceptible to impulse trauma while others may show adverse effects from harmonic disturbances or broad band mechanical agitation. One of the recognized challenges in fuel cell systems air purification is in providing a highly efficient particulate and chemical filter with minimal pressure drop. PEM integrators do not want additional parasitic loads added to the system as compensation for a highly efficient yet highly restrictive filter.more » Additionally, there is challenge in integrating multiple functions into a single air intake module tasked with effectively filtering high dust loads, diesel soot, pesticides, ammonias, and other anticipated off-road contaminants. This project has investigated both off-road associated issues cumulating in the prototype build and testing of two light duty off-road vehicles with integrated fuel cell power plant systems.« less

Inhalation dose due to presence of 131I in air above septic tank system of an endocrinology hospital.

PubMed

Mietelski, J W; Grabowska, S; Nowak, T; Bogacz, J; Gaca, P; Bartyzel, M; Budzanowski, M

2005-01-01

We present here measurements of the 131I concentration for both: gaseous and aerosol fraction of 131I in the air above the septic tank containing wastes from medical application of this isotope. Aerosols were collected using air filters, whereas gaseous forms of iodine were trapped in KI impregnated charcoal double layer cartridge. Besides an active method (pumping of the air through system of filters) an attempt for using a passive method (charcoal traps) for monitoring of radio-iodine is described. For better characterisation of a site the external kerma was determined by means of G-M and TLD techniques as well as the activity kept in the septic tank was measured by gamma spectrometry. Results show that the activity of the aerosol fraction can be neglected compared to that of the gaseous fraction. He measured activity of air is low, on the level of 1 Bq m(-3), even during simulated failure of the ventilation system. Estimated inhalation dose for the serviceman of septic tanks is low ( approximately 10%) compared with external dose obtained by such person due to gamma radiation from the tank (on the level approximately 500 nSv h(-1)). Therefore, the concept of passive monitoring of the iodine in air was abandoned. Also estimated is the efficiency of 131I reduction by a charcoal filter of the ventilation system and 131I input to the environment by the ventilation chimney.

Detection of viruses in used ventilation filters from two large public buildings.

PubMed

Goyal, Sagar M; Anantharaman, Senthilvelan; Ramakrishnan, M A; Sajja, Suchitra; Kim, Seung Won; Stanley, Nicholas J; Farnsworth, James E; Kuehn, Thomas H; Raynor, Peter C

2011-09-01

Viral and bacterial pathogens may be present in the air after being released from infected individuals and animals. Filters are installed in the heating, ventilation, and air-conditioning (HVAC) systems of buildings to protect ventilation equipment and maintain healthy indoor air quality. These filters process enormous volumes of air. This study was undertaken to determine the utility of sampling used ventilation filters to assess the types and concentrations of virus aerosols present in buildings. The HVAC filters from 2 large public buildings in Minneapolis and Seattle were sampled to determine the presence of human respiratory viruses and viruses with bioterrorism potential. Four air-handling units were selected from each building, and a total of 64 prefilters and final filters were tested for the presence of influenza A, influenza B, respiratory syncytial, corona, parainfluenza 1-3, adeno, orthopox, entero, Ebola, Marburg, Lassa fever, Machupo, eastern equine encephalitis, western equine encephalitis, and Venezuelan equine encephalitis viruses. Representative pieces of each filter were cut and eluted with a buffer solution. Attempts were made to detect viruses by inoculation of these eluates in cell cultures (Vero, MDCK, and RK-13) and specific pathogen-free embryonated chicken eggs. Two passages of eluates in cell cultures or these eggs did not reveal the presence of any live virus. The eluates were also examined by polymerase chain reaction or reverse-transcription polymerase chain reaction to detect the presence of viral DNA or RNA, respectively. Nine of the 64 filters tested were positive for influenza A virus, 2 filters were positive for influenza B virus, and 1 filter was positive for parainfluenza virus 1. These findings indicate that existing building HVAC filters may be used as a method of detection for airborne viruses. As integrated long-term bioaerosol sampling devices, they may yield valuable information on the epidemiology and aerobiology of viruses in air that can inform the development of methods to prevent airborne transmission of viruses and possible deterrents against the spread of bioterrorism agents. Copyright © 2011 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Mosby, Inc. All rights reserved.

Semi-volatile organic compounds in heating, ventilation, and air-conditioning filter dust in retail stores.

PubMed

Xu, Y; Liang, Y; Urquidi, J R; Siegel, J A

2015-02-01

Retail stores contain a wide range of products that can emit a variety of indoor pollutants. Among these chemicals, phthalate esters and polybrominated diphenyl ethers (PBDEs) are two important categories of semi-volatile organic compounds (SVOCs). Filters in heating, ventilation, and air-conditioning (HVAC) system collect particles from large volumes of air and thus potentially provide spatially and temporally integrated SVOC concentrations. This study measured six phthalate and 14 PBDE compounds in HVAC filter dust in 14 retail stores in Texas and Pennsylvania, United States. Phthalates and PBDEs were widely found in the HVAC filter dust in retail environment, indicating that they are ubiquitous indoor pollutants. The potential co-occurrence of phthalates and PBDEs was not strong, suggesting that their indoor sources are diverse. The levels of phthalates and PBDEs measured in HVAC filter dust are comparable to concentrations found in previous investigations of settled dust in residential buildings. Significant correlations between indoor air and filter dust concentrations were found for diethyl phthalate, di-n-butyl phthalate, and benzyl butyl phthalate. Reasonable agreement between measurements and an equilibrium model to describe SVOC partitioning between dust and gas-phase is achieved. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

40 CFR 63.9804 - What are my monitoring system installation, operation, and maintenance requirements?

Code of Federal Regulations, 2011 CFR

2011-07-01

... pressure or induced air fabric filters, the bag leak detector must be installed downstream of the fabric... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS FOR SOURCE CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air...

Imaging spectrometer using a liquid crystal tunable filter

NASA Astrophysics Data System (ADS)

Chrien, Thomas G.; Chovit, Christopher; Miller, Peter J.

1993-09-01

A demonstration imaging spectrometer using a liquid crystal tunable filter (LCTF) was built and tested on a hot air balloon platform. The LCTF is a tunable polarization interference or Lyot filter. The LCTF enables a small, light weight, low power, band sequential imaging spectrometer design. An overview of the prototype system is given along with a description of balloon experiment results. System model performance predictions are given for a future LCTF based imaging spectrometer design. System design considerations of LCTF imaging spectrometers are discussed.

A cellphone based system for large-scale monitoring of black carbon

NASA Astrophysics Data System (ADS)

Ramanathan, N.; Lukac, M.; Ahmed, T.; Kar, A.; Praveen, P. S.; Honles, T.; Leong, I.; Rehman, I. H.; Schauer, J. J.; Ramanathan, V.

2011-08-01

Black carbon aerosols are a major component of soot and are also a major contributor to global and regional climate change. Reliable and cost-effective systems to measure near-surface black carbon (BC) mass concentrations (hereafter denoted as [BC]) globally are necessary to validate air pollution and climate models and to evaluate the effectiveness of BC mitigation actions. Toward this goal we describe a new wireless, low-cost, ultra low-power, BC cellphone based monitoring system (BC_CBM). BC_CBM integrates a Miniaturized Aerosol filter Sampler (MAS) with a cellphone for filter image collection, transmission and image analysis for determining [BC] in real time. The BC aerosols in the air accumulate on the MAS quartz filter, resulting in a coloration of the filter. A photograph of the filter is captured by the cellphone camera and transmitted by the cellphone to the analytics component of BC_CBM. The analytics component compares the image with a calibrated reference scale (also included in the photograph) to estimate [BC]. We demonstrate with field data collected from vastly differing environments, ranging from southern California to rural regions in the Indo-Gangetic plains of Northern India, that the total BC deposited on the filter is directly and uniquely related to the reflectance of the filter in the red wavelength, irrespective of its source or how the particles were deposited. [BC] varied from 0.1 to 1 μg m -3 in Southern California and from 10 to 200 μg m -3 in rural India in our field studies. In spite of the 3 orders of magnitude variation in [BC], the BC_CBM system was able to determine the [BC] well within the experimental error of two independent reference instruments for both indoor air and outdoor ambient air. Accurate, global-scale measurements of [BC] in urban and remote rural locations, enabled by the wireless, low-cost, ultra low-power operation of BC_CBM, will make it possible to better capture the large spatial and temporal variations in [BC], informing climate science, health, and policy.

Transparent air filter for high-efficiency PM2.5 capture.

PubMed

Liu, Chong; Hsu, Po-Chun; Lee, Hyun-Wook; Ye, Meng; Zheng, Guangyuan; Liu, Nian; Li, Weiyang; Cui, Yi

2015-02-16

Particulate matter (PM) pollution has raised serious concerns for public health. Although outdoor individual protection could be achieved by facial masks, indoor air usually relies on expensive and energy-intensive air-filtering devices. Here, we introduce a transparent air filter for indoor air protection through windows that uses natural passive ventilation to effectively protect the indoor air quality. By controlling the surface chemistry to enable strong PM adhesion and also the microstructure of the air filters to increase the capture possibilities, we achieve transparent, high air flow and highly effective air filters of ~90% transparency with >95.00% removal of PM2.5 under extreme hazardous air-quality conditions (PM2.5 mass concentration >250 μg m(-3)). A field test in Beijing shows that the polyacrylonitrile transparent air filter has the best PM2.5 removal efficiency of 98.69% at high transmittance of ~77% during haze occurrence.

Transparent air filter for high-efficiency PM2.5 capture

NASA Astrophysics Data System (ADS)

Liu, Chong; Hsu, Po-Chun; Lee, Hyun-Wook; Ye, Meng; Zheng, Guangyuan; Liu, Nian; Li, Weiyang; Cui, Yi

2015-02-01

Particulate matter (PM) pollution has raised serious concerns for public health. Although outdoor individual protection could be achieved by facial masks, indoor air usually relies on expensive and energy-intensive air-filtering devices. Here, we introduce a transparent air filter for indoor air protection through windows that uses natural passive ventilation to effectively protect the indoor air quality. By controlling the surface chemistry to enable strong PM adhesion and also the microstructure of the air filters to increase the capture possibilities, we achieve transparent, high air flow and highly effective air filters of ~90% transparency with >95.00% removal of PM2.5 under extreme hazardous air-quality conditions (PM2.5 mass concentration >250 μg m-3). A field test in Beijing shows that the polyacrylonitrile transparent air filter has the best PM2.5 removal efficiency of 98.69% at high transmittance of ~77% during haze occurrence.

Does the air condition system in busses spread allergic fungi into driver space?

PubMed

Sowiak, Małgorzata; Kozajda, Anna; Jeżak, Karolina; Szadkowska-Stańczyk, Irena

2018-02-01

The aim of this study was to establish whether the air-conditioning system in buses constitutes an additional source of indoor air contamination with fungi, and whether or not the fungi concentration depends on the period from the last disinfection of the system, combined with replacement of the cabin dust particle filter. The air samples to fungi analysis using impact method were taken in 30 buses (20 with an air-conditioning system, ACS; 10 with a ventilation system, VS) in two series: 1 and 22 weeks after cabin filter replacement and disinfection of the air-conditioning system. During one test in each bus were taken two samples: before the air-conditioning or ventilation system switched on and 6 min after operating of these systems. The atmospheric air was the external background (EB). After 1 week of use of the system, the fungi concentrations before starting of the ACS and VS system were 527.8 and 1053.0 cfu/m 3 , respectively, and after 22 weeks the concentrations were 351.9 and 1069.6 cfu/m 3 , respectively. While in the sample after 6 min of ACS and VS system operating, the fungi concentration after 1 week of use was 127.6 and 233.7 cfu/m 3 , respectively, and after 22 weeks it was 113.3 and 324.9 cfu/m 3 , respectively. Results do not provide strong evidence that air-conditioning system is an additional source of indoor air contamination with fungi. A longer operation of the system promoted increase of fungi concentration in air-conditioned buses only.

Commander Truly cleans ARS filters on middeck

NASA Image and Video Library

1983-09-05

STS008-13-336 (5 Sept 1983) --- On middeck, Richard M. Truly, STS-8 commander, uses vacuum cleaner to remove debris from air revitalization system (ARS) filter assembly. Open panel on middeck floor is the ARS access panel.

Particulate matter concentrations in residences: an intervention study evaluating stand-alone filters and air conditioners.

PubMed

Batterman, S; Du, L; Mentz, G; Mukherjee, B; Parker, E; Godwin, C; Chin, J-Y; O'Toole, A; Robins, T; Rowe, Z; Lewis, T

2012-06-01

This study, a randomized controlled trial, evaluated the effectiveness of free-standing air filters and window air conditioners (ACs) in 126 low-income households of children with asthma. Households were randomized into a control group, a group receiving a free-standing HEPA filter placed in the child's sleeping area, and a group receiving the filter and a window-mounted AC. Indoor air quality (IAQ) was monitored for week-long periods over three to four seasons. High concentrations of particulate matter (PM) and carbon dioxide were frequently seen. When IAQ was monitored, filters reduced PM levels in the child's bedroom by an average of 50%. Filter use varied greatly among households and declined over time, for example, during weeks when pollutants were monitored, filter use was initially high, averaging 84±27%, but dropped to 63±33% in subsequent seasons. In months when households were not visited, use averaged only 34±30%. Filter effectiveness did not vary in homes with central or room ACs. The study shows that measurements over multiple seasons are needed to characterize air quality and filter performance. The effectiveness of interventions using free-standing air filters depends on occupant behavior, and strategies to ensure filter use should be an integral part of interventions. Environmental tobacco smoke (ETS) increased particulate matter (PM) levels by about 14 μg/m3 and was often detected using ETS-specific tracers despite restrictions on smoking in the house as reported on questionnaires administered to caregivers. PM concentrations depended on season, filter usage, relative humidity, air exchange ratios, number of children, outdoor PM levels, sweeping/dusting, and presence of a central air conditioner (AC). Free-standing air filters can be an effective intervention that provides substantial reductions in PM concentrations if the filters are used. However, filter use was variable across the study population and declined over the study duration, and thus strategies are needed to encourage and maintain use of filters. The variability in filter use suggests that exposure misclassification is a potential problem in intervention studies using filters. The installation of a room AC in the bedroom, intended to limit air exchange ratios, along with an air filter, did not lower PM levels more than the filter alone. © 2011 John Wiley & Sons A/S.

Technical Facilities and Capabilities Assessment Report

DTIC Science & Technology

1990-06-01

ARMAMENT LABORATORY Air Force Systems Command I United States Air Force I Eglin Air Force Base , Florida Best Available Copy 90 0 8 20 026 NOTICE When...The Air Force Armament Laboratory (AFATL) provides the technology base for future armament systems and supports the other elements of the deputy...color and filter digital images once an image is on the system . The IPL and the RSPL are accessible over the base Ethernet. This allows users to logon to

Filter for on-line air monitor unaffected by radon progeny and method of using same

DOEpatents

Phillips, Terrance D.; Edwards, Howard D.

1999-01-01

An apparatus for testing air having contaminants and radon progeny therein. The apparatus includes a sampling box having an inlet for receiving the air and an outlet for discharging the air. The sampling box includes a filter made of a plate of sintered stainless steel. The filter traps the contaminants, yet allows at least a portion of the radon progeny to pass therethrough. A method of testing air having contaminants and radon progeny therein. The method includes providing a testing apparatus that has a sampling box with an inlet for receiving the air and an outlet for discharging the air, and has a sintered stainless steel filter disposed within said sampling box; drawing air from a source into the sampling box using a vacuum pump; passing the air through the filter; monitoring the contaminants trapped by the filter; and providing an alarm when a selected level of contaminants is reached. The filter traps the contaminants, yet allows at least a portion of the radon progeny to pass therethrough.

78 FR 46315 - Foreign-Trade Zone (FTZ) 247-Erie, Pennsylvania, Notification of Proposed Production Activity, GE...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-31

...; cover assemblies; strainer assemblies; oil filter assemblies; air filter assemblies; screen assemblies; filter assemblies; breather assemblies; filter box assemblies; sand trap assemblies; valve stems; brake... holders; staples; rivets; brazing alloys; diesel engines; frame assemblies; air inlets; filter box air...

Effects of diesel exhaust aftertreatment devices on concentrations and size distribution of aerosols in underground mine air.

PubMed

Bugarski, Aleksandar D; Schnakenberg, George H; Hummer, Ion A; Cauda, Emanuele; Janisko, Samuel I; Patts, Larry D

2009-09-01

Three types of uncatalyzed diesel particulate filter (DPF) systems, three types of high-temperature disposable filter elements (DFEs), and one diesel oxidation catalytic converter (DOC) were evaluated in underground mine conditions for their effects on the concentrations and size distributions of diesel aerosols. Those effects were compared with the effects of a standard muffler. The experimental work was conducted directly in an underground environment using a unique diesel laboratory developed in an underground experimental mine. The DPF systems reduced total mass of aerosols in the mine air approximately 10-fold for light-load and 20-fold or more for high-load test conditions. The DFEs offered similar reductions in aerosol mass concentrations. The efficiency of the new DFEs significantly increased with accumulation of operating time and buildup of diesel particulate matter in the porous structure of the filter elements. A single laundering process did not exhibit substantial effects on performance of the filter element The effectiveness of DPFs and DFEs in removing aerosols by number was strongly influenced by engine operating mode. The concentrations of nucleation mode aerosols in the mine air were found to be substantially higher for both DPFs and DFEs when the engine was operated at high-load modes than at low-load modes. The effects of the DOC on mass and number concentrations of aerosols in mine air were relatively minor when compared to those of the DPF and DFE systems.

True Measures

ERIC Educational Resources Information Center

Cox, Ron

2010-01-01

Air filters perform an important function in commercial and institutional facilities. Because indoor air typically is two to five times more polluted than outdoor air, air filters are needed to remove respirable particles such as microorganisms, dust and allergens from the breathing air. In fact, air filters provide the primary defense for…

Sampled-Data Kalman Filtering and Multiple Model Adaptive Estimation for Infinite-Dimensional Continuous-Time Systems

DTIC Science & Technology

2007-03-01

mathematical frame- 1-6 work of linear algebra and functional analysis [122, 33], while Kalman-Bucy filtering [96, 32] is an especially important...Engineering, Air Force Institute of Technology (AU), Wright- Patterson AFB, Ohio, March 2002. 85. Hoffman, Kenneth and Ray Kunze. Linear Algebra (Second Edition...Engineering, Air Force Institute of Technology (AU), Wright- Patterson AFB, Ohio, December 1989. 189. Strang, Gilbert. Linear Algebra and Its Applications

First report of Legionella pneumophila in car cabin air filters. Are these a potential exposure pathway for professional drivers?

PubMed

Alexandropoulou, Ioanna G; Konstantinidis, Theocharis G; Parasidis, Theodoros A; Nikolaidis, Christos; Panopoulou, Maria; Constantinidis, Theodoros C

2013-12-01

Recent findings have identified professional drivers as being at an increased risk of Legionnaires' disease. Our hypothesis was that used car cabin air filters represent a reservoir of Legionella bacteria, and thus a potential pathway for contamination. We analysed used cabin air filters from various types of car. The filters were analysed by culture and by molecular methods. Our findings indicated that almost a third of air filters were colonized with Legionella pneumophila. Here, we present the first finding of Legionella spp. in used car cabin air filters. Further investigations are needed in order to confirm this exposure pathway. The presence of Legionella bacteria in used cabin air filters may have been an unknown source of infection until now.

42 CFR 84.181 - Non-powered air-purifying particulate filter efficiency level determination.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 42 Public Health 1 2010-10-01 2010-10-01 false Non-powered air-purifying particulate filter...-purifying particulate filter efficiency level determination. (a) Twenty filters of each non-powered air-purifying particulate respirator model shall be tested for filter efficiency against: (1) A solid sodium...

42 CFR 84.181 - Non-powered air-purifying particulate filter efficiency level determination.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 42 Public Health 1 2011-10-01 2011-10-01 false Non-powered air-purifying particulate filter...-purifying particulate filter efficiency level determination. (a) Twenty filters of each non-powered air-purifying particulate respirator model shall be tested for filter efficiency against: (1) A solid sodium...

42 CFR 84.181 - Non-powered air-purifying particulate filter efficiency level determination.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 42 Public Health 1 2012-10-01 2012-10-01 false Non-powered air-purifying particulate filter...-purifying particulate filter efficiency level determination. (a) Twenty filters of each non-powered air-purifying particulate respirator model shall be tested for filter efficiency against: (1) A solid sodium...

42 CFR 84.181 - Non-powered air-purifying particulate filter efficiency level determination.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 42 Public Health 1 2014-10-01 2014-10-01 false Non-powered air-purifying particulate filter...-purifying particulate filter efficiency level determination. (a) Twenty filters of each non-powered air-purifying particulate respirator model shall be tested for filter efficiency against: (1) A solid sodium...

42 CFR 84.181 - Non-powered air-purifying particulate filter efficiency level determination.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 42 Public Health 1 2013-10-01 2013-10-01 false Non-powered air-purifying particulate filter...-purifying particulate filter efficiency level determination. (a) Twenty filters of each non-powered air-purifying particulate respirator model shall be tested for filter efficiency against: (1) A solid sodium...

Impact of different supply air and recirculating air filtration systems on stable climate, animal health, and performance of fattening pigs in a commercial pig farm

PubMed Central

Wenke, Cindy; Pospiech, Janina; Reutter, Tobias; Altmann, Bettina; Truyen, Uwe

2018-01-01

Biosecurity is defined as the implementation of measures that reduce the risk of disease agents being introduced and/or spread. For pig production, several of these measures are routinely implemented (e.g. cleaning, disinfection, segregation). However, air as a potential vector of pathogens has long been disregarded. Filters for incoming and recirculating air were installed into an already existing ventilation plant at a fattening piggery (3,840 pigs at maximum) in Saxony, Germany. Over a period of three consecutive fattening periods, we evaluated various parameters including air quality indices, environmental and operating parameters, and pig performance. Animal data regarding respiratory diseases, presence of antibodies against influenza A viruses, PRRSV, and Actinobacillus pleuropneumoniae and lung health score at slaughter were recorded, additionally. There were no significant differences (p = 0.824) in total bacterial counts between barns with and without air filtration. Recirculating air filtration resulted in the lowest total dust concentration (0.12 mg/m3) and lung health was best in animals from the barn equipped with recirculating air filtration modules. However, there was no difference in animal performance. Antibodies against all above mentioned pathogens were detected but mostly animals were already antibody-positive at re-stocking. We demonstrated that supply air filtration as well as recirculating air filtration technique can easily be implemented in an already existing ventilation system and that recirculating air filtration resulted in enhanced lung health compared to supply air-filtered and non-filtered barns. A more prominent effect might have been obtained in a breeding facility because of the longer life span of sows and a higher biosecurity level with air filtration as an add-on measure. PMID:29558482

High-efficiency particulate air filter test stand and aerosol generator for particle loading studies

NASA Astrophysics Data System (ADS)

Arunkumar, R.; Hogancamp, Kristina U.; Parsons, Michael S.; Rogers, Donna M.; Norton, Olin P.; Nagel, Brian A.; Alderman, Steven L.; Waggoner, Charles A.

2007-08-01

This manuscript describes the design, characterization, and operational range of a test stand and high-output aerosol generator developed to evaluate the performance of 30×30×29cm3 nuclear grade high-efficiency particulate air (HEPA) filters under variable, highly controlled conditions. The test stand system is operable at volumetric flow rates ranging from 1.5to12standardm3/min. Relative humidity levels are controllable from 5%-90% and the temperature of the aerosol stream is variable from ambient to 150°C. Test aerosols are produced through spray drying source material solutions that are introduced into a heated stainless steel evaporation chamber through an air-atomizing nozzle. Regulation of the particle size distribution of the aerosol challenge is achieved by varying source solution concentrations and through the use of a postgeneration cyclone. The aerosol generation system is unique in that it facilitates the testing of standard HEPA filters at and beyond rated media velocities by consistently providing, into a nominal flow of 7standardm3/min, high mass concentrations (˜25mg/m3) of dry aerosol streams having count mean diameters centered near the most penetrating particle size for HEPA filters (120-160nm). Aerosol streams that have been generated and characterized include those derived from various concentrations of KCl, NaCl, and sucrose solutions. Additionally, a water insoluble aerosol stream in which the solid component is predominantly iron (III) has been produced. Multiple ports are available on the test stand for making simultaneous aerosol measurements upstream and downstream of the test filter. Types of filter performance related studies that can be performed using this test stand system include filter lifetime studies, filtering efficiency testing, media velocity testing, evaluations under high mass loading and high humidity conditions, and determination of the downstream particle size distributions.

High-efficiency particulate air filter test stand and aerosol generator for particle loading studies.

PubMed

Arunkumar, R; Hogancamp, Kristina U; Parsons, Michael S; Rogers, Donna M; Norton, Olin P; Nagel, Brian A; Alderman, Steven L; Waggoner, Charles A

2007-08-01

This manuscript describes the design, characterization, and operational range of a test stand and high-output aerosol generator developed to evaluate the performance of 30 x 30 x 29 cm(3) nuclear grade high-efficiency particulate air (HEPA) filters under variable, highly controlled conditions. The test stand system is operable at volumetric flow rates ranging from 1.5 to 12 standard m(3)/min. Relative humidity levels are controllable from 5%-90% and the temperature of the aerosol stream is variable from ambient to 150 degrees C. Test aerosols are produced through spray drying source material solutions that are introduced into a heated stainless steel evaporation chamber through an air-atomizing nozzle. Regulation of the particle size distribution of the aerosol challenge is achieved by varying source solution concentrations and through the use of a postgeneration cyclone. The aerosol generation system is unique in that it facilitates the testing of standard HEPA filters at and beyond rated media velocities by consistently providing, into a nominal flow of 7 standard m(3)/min, high mass concentrations (approximately 25 mg/m(3)) of dry aerosol streams having count mean diameters centered near the most penetrating particle size for HEPA filters (120-160 nm). Aerosol streams that have been generated and characterized include those derived from various concentrations of KCl, NaCl, and sucrose solutions. Additionally, a water insoluble aerosol stream in which the solid component is predominantly iron (III) has been produced. Multiple ports are available on the test stand for making simultaneous aerosol measurements upstream and downstream of the test filter. Types of filter performance related studies that can be performed using this test stand system include filter lifetime studies, filtering efficiency testing, media velocity testing, evaluations under high mass loading and high humidity conditions, and determination of the downstream particle size distributions.

Nuclear air cleaning: the need for a change in emphasis

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

Carbaugh, E.H.

1982-11-01

The nuclear industry now has over 35 years of experience in nuclear air cleaning. This experience covers technology development, system design, operations, and maintenance. Much of the past experience has been directed towards technology development with particular emphasis on high efficiency particulate air (HEPA) filters. Implementation of this technology has lagged its development by a number of years. A recent study examines the cause and frequencies of HEPA filter changeouts and failures. These data lead to a conclusion that a shift in emphasis from technology development to the training of personnel and the designing and maintaining of such systems ismore » needed. Some highlights of the data and a discussion of topics which should be addressed in training will be presented.« less

Development of an Indexing Media Filtration System for Long Duration Space Missions

NASA Technical Reports Server (NTRS)

Agui, Juan H.; Vijayakumar, R.

2013-01-01

The effective maintenance of air quality aboard spacecraft cabins will be vital to future human exploration missions. A key component will be the air cleaning filtration system which will need to remove a broad size range of particles including skin flakes, hair and clothing fibers, other biological matter, and particulate matter derived from material and equipment wear. In addition, during surface missions any extraterrestrial planetary dust, including dust generated by near-by ISRU equipment, which is tracked into the habitat will also need to be managed by the filtration system inside the pressurized habitat compartments. An indexing media filter system is being developed to meet the demand for long-duration missions that will result in dramatic increases in filter service life and loading capacity, and will require minimal crew involvement. These features may also benefit other closed systems, such as submarines, and remote location terrestrial installations where servicing and replacement of filter units is not practical. The filtration system consists of three stages: an inertial impactor stage, an indexing media stage, and a high-efficiency filter stage, packaged in a stacked modular cartridge configuration. Each stage will target a specific range of particle sizes that optimize the filtration and regeneration performance of the system. An 1/8th scale and full-scale prototype of the filter system have been fabricated and have been tested in the laboratory and reduced gravity environments that simulate conditions on spacecrafts, landers and habitats. Results from recent laboratory and reducegravity flight tests data will be presented.

OPERATIONAL TEST AND EVALUATION OF PHOTOTROPIC GOGGLES.

DTIC Science & Technology

Irreversible Phototropic Filter Device is one of many such systems. Forty-nine Air Defense Command and twenty-four Tactical Air Command aircrews evaluated the...indicated that: The goggles do not integrate with the oxygen mask, helmet and visor; It is not practicable to carry additional phototropic lenses for...in-flight changes. The Irreversible Phototropic Filter Device is operationally unacceptable for use by aircrew members. Recommend that ASD continue efforts to develop a suitable device for flashblindness protection. (Author)

MO-FG-CAMPUS-IeP1-04: Kerma Area Product Calculation for Non-Uniform X-Ray Fields Using a Skin Dose Tracking System

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

Vijayan, S; Xiong, Z; Rudin, S

Purpose: The functionality of the Dose-Tracking System (DTS) has been expanded to include the calculation of the Kerma-Area Product (KAP) for non-uniform x-ray fields such as result from the use of compensation filters during fluoroscopic procedures Methods: The DTS calculates skin dose during fluoroscopic interventions and provides a color-coded dose map on a patient-graphic model. The KAP is the integral of air kerma over the x-ray field and is usually measured with a transmission-ionization chamber that intercepts the entire x-ray beam. The DTS has been modified to determine KAP when there are beam non-uniformities that can be modeled. For example,more » the DTS includes models of the three compensation filters with tapered edges located in the collimator assembly of the Toshiba Infinix fluoroscopic C-Arm and can track their movement. To determine the air kerma after the filters, DTS includes transmission factors for the compensation filters as a function of kVp and beam filtration. A virtual KAP dosimeter is simulated in the DTS by an array of graphic vertices; the air kerma at each vertex is corrected by the field non-uniformity, which in this case is the attenuation factor for those rays which pass through the filter. The products of individual vertex air-kerma values for all vertices within the beam times the effective-area-per-vertex are summed for each x-ray pulse to yield the KAP per pulse and the cumulative KAP for the procedure is then calculated. Results: The KAP values estimated by DTS with the compensation filter inserted into the x-ray field agree within ± 6% with the values displayed on the fluoroscopy unit monitor, which are measured with a transmission chamber. Conclusion: The DTS can account for field non-uniformities such as result from the use of compensation filters in calculating KAP and can obviate the need for a KAP transmission ionization chamber. Partial support from NIH Grant R01-EB002873 and Toshiba Medical Systems Corp.« less

Evaluation of BAUER High Pressure Breathing Air P-2 Purification System

DTIC Science & Technology

1991-08-01

and is a coalescing type separator that removes oil and water vapors suspended in the compressed air . The molecular sieve is made to adsorb oil and...filtering, moisture separation, and prevents compressed air return from the charged air storage flasks to the compressor during unit shutdown. A manual...1111111111111 1111 IE IH fil91i C NAVY EXPERIMENTAL DIVING UNIT REPORT NO. 10-91 EVALUATION OF BAUER HIGH PRESSURE BREATHING AIR P-2 PURIFICATION SYSTEM GEORGE D

Acaroid mite allergens from the filters of air-conditioning system in China.

PubMed

Li, Chao-Pin; Guo, Wei; Zhan, Xiao-Dong; Zhao, Bei-Bei; Diao, Ji-Dong; Li, Na; He, Lian-Ping

2014-01-01

Accumulation of acaroid mites in the filters of air-conditioners is harmful to human health. It is important to clarify the allergen components of mites from the filters of local air-conditioning system. The present study was to detect the allergen types in the filters of air-conditioners and assesse their allergenicity by asthmatic models. Sixty aliquots of dust samples were collected from air conditioning filters in civil houses in Wuhu area. Total protein was extracted from the dust samples using PBS and quantified by Bradford method. Allergens I and II were also detected by Western blot using primary antibody (anti-Der f1/2, Der p1/Der f2/Der p2, respectively). Ten aliquots of the positive samples were randomly selected for homogenization and sensitized the mice for developing asthmatic animal models. Total serum IgE level and IFN-γ, IL-4 and IL-5 in the bronchoalveolar lavage fluid (BALF). The allergenicity of the extraction was assessed using pathological sections developed from the mouse pulmonary tissues. The concentration of extract from the 60 samples was ranged from 4.37 μg/ml to 30.76 μg/ml. After analyzing with Western blot, 31 of 60 samples were positive for 4 allergens of acaroid mites, and yet 16 were negative. The levels of total IgE from serum IL-4 and IL-5 from the BALF in the experimental group were apparently higher than that of negative control and PBS group (P < 0.01), but there were no statistical difference compared to OVA group (P > 0.05). However,the IFN-γ level in BALF was lower compared with the negative control and PBS group (P < 0.05) but with the OVA group (P > 0.05). The pathological changes were evidently emerged in pulmonary tissues, which were similar to those of OVA group, compared with the PBS ground and negative controls. The air-conditioner filters in human dwellings of Wuhu area potentially contain the major group allergen 1 and 2 from D. farinae and D. pteronyssinus, which may be associated with seasonal prevalence of allergic disorders in this area.

Acaroid mite allergens from the filters of air-conditioning system in China

PubMed Central

Li, Chao-Pin; Guo, Wei; Zhan, Xiao-Dong; Zhao, Bei-Bei; Diao, Ji-Dong; Li, Na; He, Lian-Ping

2014-01-01

Accumulation of acaroid mites in the filters of air-conditioners is harmful to human health. It is important to clarify the allergen components of mites from the filters of local air-conditioning system. The present study was to detect the allergen types in the filters of air-conditioners and assesse their allergenicity by asthmatic models. Sixty aliquots of dust samples were collected from air conditioning filters in civil houses in Wuhu area. Total protein was extracted from the dust samples using PBS and quantified by Bradford method. Allergens I and II were also detected by Western blot using primary antibody (anti-Der f1/2, Der p1/Der f2/Der p2, respectively). Ten aliquots of the positive samples were randomly selected for homogenization and sensitized the mice for developing asthmatic animal models. Total serum IgE level and IFN-γ, IL-4 and IL-5 in the bronchoalveolar lavage fluid (BALF). The allergenicity of the extraction was assessed using pathological sections developed from the mouse pulmonary tissues. The concentration of extract from the 60 samples was ranged from 4.37 μg/ml to 30.76 μg/ml. After analyzing with Western blot, 31 of 60 samples were positive for 4 allergens of acaroid mites, and yet 16 were negative. The levels of total IgE from serum IL-4 and IL-5 from the BALF in the experimental group were apparently higher than that of negative control and PBS group (P < 0.01), but there were no statistical difference compared to OVA group (P > 0.05). However,the IFN-γ level in BALF was lower compared with the negative control and PBS group (P < 0.05) but with the OVA group (P > 0.05). The pathological changes were evidently emerged in pulmonary tissues, which were similar to those of OVA group, compared with the PBS ground and negative controls. The air-conditioner filters in human dwellings of Wuhu area potentially contain the major group allergen 1 and 2 from D. farinae and D. pteronyssinus, which may be associated with seasonal prevalence of allergic disorders in this area. PMID:25035772

78 FR 16604 - Airworthiness Directives; Diamond Aircraft Industries GmbH Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2013-03-18

... unsafe condition as the engine air inlet filter is subject to icing. We are issuing this AD to require... warmer air conditions. The subsequent investigation identified that the engine air inlet filter is... with a manually controlled alternate air valve which bypasses the inlet air filter and provides...

Preparation of Fiber Based Binder Materials to Enhance the Gas Adsorption Efficiency of Carbon Air Filter.

PubMed

Lim, Tae Hwan; Choi, Jeong Rak; Lim, Dae Young; Lee, So Hee; Yeo, Sang Young

2015-10-01

Fiber binder adapted carbon air filter is prepared to increase gas adsorption efficiency and environmental stability. The filter prevents harmful gases, as well as particle dusts in the air from entering the body when a human inhales. The basic structure of carbon air filter is composed of spunbond/meltblown/activated carbon/bottom substrate. Activated carbons and meltblown layer are adapted to increase gas adsorption and dust filtration efficiency, respectively. Liquid type adhesive is used in the conventional carbon air filter as a binder material between activated carbons and other layers. However, it is thought that the liquid binder is not an ideal material with respect to its bonding strength and liquid flow behavior that reduce gas adsorption efficiency. To overcome these disadvantages, fiber type binder is introduced in our study. It is confirmed that fiber type binder adapted air filter media show higher strip strength, and their gas adsorption efficiencies are measured over 42% during 60 sec. These values are higher than those of conventional filter. Although the differential pressure of fiber binder adapted air filter is relatively high compared to the conventional one, short fibers have a good potential as a binder materials of activated carbon based air filter.

Adequate model complexity for scenario analysis of VOC stripping in a trickling filter.

PubMed

Vanhooren, H; Verbrugge, T; Boeije, G; Demey, D; Vanrolleghem, P A

2001-01-01

Two models describing the stripping of volatile organic contaminants (VOCs) in an industrial trickling filter system are developed. The aim of the models is to investigate the effect of different operating conditions (VOC loads and air flow rates) on the efficiency of VOC stripping and the resulting concentrations in the gas and liquid phases. The first model uses the same principles as the steady-state non-equilibrium activated sludge model Simple Treat, in combination with an existing biofilm model. The second model is a simple mass balance based model only incorporating air and liquid and thus neglecting biofilm effects. In a first approach, the first model was incorporated in a five-layer hydrodynamic model of the trickling filter, using the carrier material design specifications for porosity, water hold-up and specific surface area. A tracer test with lithium was used to validate this approach, and the gas mixing in the filters was studied using continuous CO2 and O2 measurements. With the tracer test results, the biodegradation model was adapted, and it became clear that biodegradation and adsorption to solids can be neglected. On this basis, a simple dynamic mass balance model was built. Simulations with this model reveal that changing the air flow rate in the trickling filter system has little effect on the VOC stripping efficiency at steady state. However, immediately after an air flow rate change, quite high flux and concentration peaks of VOCs can be expected. These phenomena are of major importance for the design of an off-gas treatment facility.

Ground-Based Aerosol Measurements | Science Inventory ...

EPA Pesticide Factsheets

Atmospheric particulate matter (PM) is a complex chemical mixture of liquid and solid particles suspended in air (Seinfeld and Pandis 2016). Measurements of this complex mixture form the basis of our knowledge regarding particle formation, source-receptor relationships, data to test and verify complex air quality models, and how PM impacts human health, visibility, global warming, and ecological systems (EPA 2009). Historically, PM samples have been collected on filters or other substrates with subsequent chemical analysis in the laboratory and this is still the major approach for routine networks (Chow 2005; Solomon et al. 2014) as well as in research studies. In this approach, air, at a specified flow rate and time period, is typically drawn through an inlet, usually a size selective inlet, and then drawn through filters, 1 INTRODUCTION Atmospheric particulate matter (PM) is a complex chemical mixture of liquid and solid particles suspended in air (Seinfeld and Pandis 2016). Measurements of this complex mixture form the basis of our knowledge regarding particle formation, source-receptor relationships, data to test and verify complex air quality models, and how PM impacts human health, visibility, global warming, and ecological systems (EPA 2009). Historically, PM samples have been collected on filters or other substrates with subsequent chemical analysis in the laboratory and this is still the major approach for routine networks (Chow 2005; Solomo

Technology Solutions Case Study: Ventilation System Effectiveness and Tested Indoor Air Quality Impacts

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

A. Rudd and D. Bergey

Ventilation system effectiveness testing was conducted at two unoccupied, single-family, detached lab homes at the University of Texas - Tyler. Five ventilation system tests were conducted with various whole-building ventilation systems. Multizone fan pressurization testing characterized building and zone enclosure leakage. PFT testing showed multizone air change rates and interzonal airflow filtration. Indoor air recirculation by a central air distribution system can help improve the exhaust ventilation system by way of air mixing and filtration. In contrast, the supply and balanced ventilation systems showed that there is a significant benefit to drawing outside air from a known outside location, andmore » filtering and distributing that air. Compared to the Exhaust systems, the CFIS and ERV systems showed better ventilation air distribution and lower concentrations of particulates, formaldehyde and other VOCs.« less

Effect of Intake Air Filter Condition on Vehicle Fuel Economy

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

Norman, Kevin M; Huff, Shean P; West, Brian H

2009-02-01

The U.S. Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy and the U.S. Environmental Protection Agency (EPA) jointly maintain a fuel economy website (www.fueleconomy.gov), which helps fulfill their responsibility under the Energy Policy Act of 1992 to provide accurate fuel economy information [in miles per gallon (mpg)] to consumers. The site provides information on EPA fuel economy ratings for passenger cars and light trucks from 1985 to the present and other relevant information related to energy use such as alternative fuels and driving and vehicle maintenance tips. In recent years, fluctuations in the price of crude oilmore » and corresponding fluctuations in the price of gasoline and diesel fuels have renewed interest in vehicle fuel economy in the United States. (User sessions on the fuel economy website exceeded 20 million in 2008 compared to less than 5 million in 2004 and less than 1 million in 2001.) As a result of this renewed interest and the age of some of the references cited in the tips section of the website, DOE authorized the Oak Ridge National Laboratory (ORNL) Fuels, Engines, and Emissions Research Center (FEERC) to initiate studies to validate and improve these tips. This report documents a study aimed specifically at the effect of engine air filter condition on fuel economy. The goal of this study was to explore the effects of a clogged air filter on the fuel economy of vehicles operating over prescribed test cycles. Three newer vehicles (a 2007 Buick Lucerne, a 2006 Dodge Charger, and a 2003 Toyota Camry) and an older carbureted vehicle were tested. Results show that clogging the air filter has no significant effect on the fuel economy of the newer vehicles (all fuel injected with closed-loop control and one equipped with MDS). The engine control systems were able to maintain the desired AFR regardless of intake restrictions, and therefore fuel consumption was not increased. The carbureted engine did show a decrease in fuel economy with increasing restriction. However, the level of restriction required to cause a substantial (10-15%) decrease in fuel economy (such as that cited in the literature) was so severe that the vehicle was almost undrivable. Acceleration performance on all vehicles was improved with a clean air filter. Once it was determined how severe the restriction had to be to affect the carbureted vehicle fuel economy, the 2007 Buick Lucerne was retested in a similar manner. We were not able to achieve the level of restriction that was achieved with the 1972 Pontiac with the Lucerne. The Lucerne's air filter box would not hold the filter in place under such severe conditions. (It is believed that this testing exceeded the design limits of the air box.) Tests were conducted at a lower restriction level (although still considerably more severe than the initial clogged filter testing), allowing the air filter to stay seated in the air box, and no significant change was observed in the Lucerne's fuel economy or the AFR over the HFET cycle. Closed-loop control in modern fuel injected vehicle applications is sophisticated enough to keep a clogged air filter from affecting the vehicle fuel economy. However for older, open-loop, carbureted vehicles, a clogged air filter can affect the fuel economy. For the vehicle tested, the fuel economy with a new air filter improved as much as 14% over that with a severely clogged filter (in which the filter was so clogged that drivability was impacted). Under a more typical state of clog, the improvement with a new filter ranged from 2 to 6%.« less

Wildfire Smoke

MedlinePlus

... keep the fresh-air intake closed and the filter clean to prevent outdoor smoke from getting inside. ... inside with the windows closed. Use an air filter . Use a freestanding indoor air filter with particle ...

Efficiency of different air filter types for pig facilities at laboratory scale

PubMed Central

Wenke, Cindy; Pospiech, Janina; Reutter, Tobias; Truyen, Uwe

2017-01-01

Air filtration has been shown to be efficient in reducing pathogen burden in circulating air. We determined at laboratory scale the retention efficiency of different air filter types either composed of a prefilter (EU class G4) and a secondary fiberglass filter (EU class F9) or consisting of a filter mat (EU class M6 and F8-9). Four filter prototypes were tested for their capability to remove aerosol containing equine arteritis virus (EAV), porcine reproductive and respiratory syndrome virus (PRRSV), bovine enterovirus 1 (BEV), Actinobacillus pleuropneumoniae (APP), and Staphylococcus (S.) aureus from air. Depending on the filter prototype and utilisation, the airflow was set at 1,800 m3/h (combination of upstream prefilter and fiberglass filter) or 80 m3/h (filter mat). The pathogens were aerosolized and their concentration was determined in front of and behind the filter by culture or quantitative real-time RT-PCR. Furthermore, survival of the pathogens over time in the filter material was determined. Bacteria were most efficiently filtered with a reduction rate of up to 99.9% depending on the filter used. An approximately 98% reduction was achieved for the viruses tested. Viability or infectivity of APP or PRRSV in the filter material decreased below the detection limit after 4 h and 24 h, respectively, whereas S. aureus was still culturable after 4 weeks. Our results demonstrate that pathogens can efficiently be reduced by air filtration. Consequently, air filtration combined with other strict biosecurity measures markedly reduces the risk of introducing airborne transmitted pathogens to animal facilities. In addition, air filtration might be useful in reducing bioaerosols within a pig barn, hence improving respiratory health of pigs. PMID:29028843

Efficiency of different air filter types for pig facilities at laboratory scale.

PubMed

Wenke, Cindy; Pospiech, Janina; Reutter, Tobias; Truyen, Uwe; Speck, Stephanie

2017-01-01

Air filtration has been shown to be efficient in reducing pathogen burden in circulating air. We determined at laboratory scale the retention efficiency of different air filter types either composed of a prefilter (EU class G4) and a secondary fiberglass filter (EU class F9) or consisting of a filter mat (EU class M6 and F8-9). Four filter prototypes were tested for their capability to remove aerosol containing equine arteritis virus (EAV), porcine reproductive and respiratory syndrome virus (PRRSV), bovine enterovirus 1 (BEV), Actinobacillus pleuropneumoniae (APP), and Staphylococcus (S.) aureus from air. Depending on the filter prototype and utilisation, the airflow was set at 1,800 m3/h (combination of upstream prefilter and fiberglass filter) or 80 m3/h (filter mat). The pathogens were aerosolized and their concentration was determined in front of and behind the filter by culture or quantitative real-time RT-PCR. Furthermore, survival of the pathogens over time in the filter material was determined. Bacteria were most efficiently filtered with a reduction rate of up to 99.9% depending on the filter used. An approximately 98% reduction was achieved for the viruses tested. Viability or infectivity of APP or PRRSV in the filter material decreased below the detection limit after 4 h and 24 h, respectively, whereas S. aureus was still culturable after 4 weeks. Our results demonstrate that pathogens can efficiently be reduced by air filtration. Consequently, air filtration combined with other strict biosecurity measures markedly reduces the risk of introducing airborne transmitted pathogens to animal facilities. In addition, air filtration might be useful in reducing bioaerosols within a pig barn, hence improving respiratory health of pigs.

Screening system and method of using same

DOEpatents

Jones, David A; Gresham, Christopher A; Basiliere, Marc L; Spates, James J; Rodacy, Philip J

2014-04-15

An integrated apparatus and method for screening an object for a target material is provided. The integrated apparatus comprises a housing and an integrated screener. The housing is positionable adjacent the object, and has a channel therethrough. The integrated screener is positionable in the housing, and comprises a fan, at least one filter, a heater and an analyzer. The fan is for drawing air carrying particles and vapor through the channel of the housing. The filter(s) is/are positionable in the channel of the housing for passage of the air therethrough. The filter(s) comprise(s) at least one metal foam having a plurality of pores therein for collecting and adsorbing a sample from the particles and vapor passing therethrough. The heater is for applying heat to the at least one metal foam whereby the collected sample is desorbed from the metal foam. The analyzer detects the target material from the desorbed sample.

40 CFR 610.21 - Device functional category and vehicle system effects.

Code of Federal Regulations, 2012 CFR

2012-07-01

... device's category will be based on: (1) Engineering principles governing operation of the device; (2... mechanical) All. Vapor Injectors All. Choke controls 1, 2, and 4. Air filters 1, 2, and 4. Fuel-air...

40 CFR 610.21 - Device functional category and vehicle system effects.

Code of Federal Regulations, 2014 CFR

2014-07-01

... device's category will be based on: (1) Engineering principles governing operation of the device; (2... mechanical) All. Vapor Injectors All. Choke controls 1, 2, and 4. Air filters 1, 2, and 4. Fuel-air...

40 CFR 610.21 - Device functional category and vehicle system effects.

Code of Federal Regulations, 2013 CFR

2013-07-01

... device's category will be based on: (1) Engineering principles governing operation of the device; (2... mechanical) All. Vapor Injectors All. Choke controls 1, 2, and 4. Air filters 1, 2, and 4. Fuel-air...

Recirculating electric air filter

DOEpatents

Bergman, Werner

1986-01-01

An electric air filter cartridge has a cylindrical inner high voltage eleode, a layer of filter material, and an outer ground electrode formed of a plurality of segments moveably connected together. The outer electrode can be easily opened to remove or insert filter material. Air flows through the two electrodes and the filter material and is exhausted from the center of the inner electrode.

Recirculating electric air filter

DOEpatents

Bergman, W.

1985-01-09

An electric air filter cartridge has a cylindrical inner high voltage electrode, a layer of filter material, and an outer ground electrode formed of a plurality of segments moveably connected together. The outer electrode can be easily opened to remove or insert filter material. Air flows through the two electrodes and the filter material and is exhausted from the center of the inner electrode.

Air-flow regulation system for a coal gasifier

DOEpatents

Fasching, George E.

1984-01-01

An improved air-flow regulator for a fixed-bed coal gasifier is provided which allows close air-flow regulation from a compressor source even though the pressure variations are too rapid for a single primary control loop to respond. The improved system includes a primary controller to control a valve in the main (large) air supply line to regulate large slow changes in flow. A secondary controller is used to control a smaller, faster acting valve in a secondary (small) air supply line parallel to the main line valve to regulate rapid cyclic deviations in air flow. A low-pass filter with a time constant of from 20 to 50 seconds couples the output of the secondary controller to the input of the primary controller so that the primary controller only responds to slow changes in the air-flow rate, the faster, cyclic deviations in flow rate sensed and corrected by the secondary controller loop do not reach the primary controller due to the high frequency rejection provided by the filter. This control arrangement provides at least a factor of 5 improvement in air-flow regulation for a coal gasifier in which air is supplied by a reciprocating compressor through a surge tank.

Allergy-Proof Your House

MedlinePlus

... small-particle or high-efficiency particulate air (HEPA) filter. Shampoo the carpet frequently. Curtains and blinds. Use ... dander they shed. Air filtration. Choose an air filter that has a small-particle or HEPA filter. ...

Plants Clean Air and Water for Indoor Environments

NASA Technical Reports Server (NTRS)

2007-01-01

Wolverton Environmental Services Inc., founded by longtime government environmental scientist B.C. "Bill" Wolverton, is an environmental consulting firm that gives customers access to the results of his decades of cutting-edge bioremediation research. Findings about how to use plants to improve indoor air quality have been published in dozens of NASA technical papers and in the book, "How to Grow Fresh Air: 50 Houseplants That Purify Your Home or Office." The book has now been translated into 12 languages and has been on the shelves of bookstores for nearly 10 years. A companion book, "Growing Clean Water: Nature's Solution to Water Pollution," explains how plants can clean waste water. Other discoveries include that the more air that is allowed to circulate through the roots of the plants, the more effective they are at cleaning polluted air; and that plants play a psychological role in welfare in that people recover from illness faster in the presence of plants. Wolverton Environmental is also working in partnership with Syracuse University, to engineer systems consisting of modular wicking filters tied into duct work and water supplies, essentially tying plant-based filters into heating, ventilation, and air conditioning (HVAC) systems. Also, the company has recently begun to assess the ability of the EcoPlanter to remove formaldehyde from interior environments. Wolverton Environmental is also in talks with designers of the new Stennis Visitor's Center, who are interested in using its designs for indoor air-quality filters

Particulate matter concentrations in residences: an intervention study evaluating stand-alone filters and air conditioners

PubMed Central

Batterman, S.; Du, L.; Mentz, G.; Mukherjee, B.; Parker, E.; Godwin, C.; Chin, J.-Y.; O'Toole, A.; Robins, T.; Rowe, Z.; Lewis, T.

2014-01-01

This study, a randomized controlled trial, evaluated the effectiveness of free-standing air filters and window air conditioners (ACs) in 126 low-income households of children with asthma. Households were randomized into a control group, a group receiving a free-standing HEPA filter placed in the child's sleeping area, and a group receiving the filter and a window-mounted AC. Indoor air quality (IAQ) was monitored for week-long periods over three to four seasons. High concentrations of particulate matter (PM) and carbon dioxide were frequently seen. When IAQ was monitored, filters reduced PM levels in the child's bedroom by an average of 50%. Filter use varied greatly among households and declined over time, for example, during weeks when pollutants were monitored, filter use was initially high, averaging 84 ± 27%, but dropped to 63 ± 33% in subsequent seasons. In months when households were not visited, use averaged only 34 ± 30%. Filter effectiveness did not vary in homes with central or room ACs. The study shows that measurements over multiple seasons are needed to characterize air quality and filter performance. The effectiveness of interventions using free-standing air filters depends on occupant behavior, and strategies to ensure filter use should be an integral part of interventions. PMID:22145709

Looking into Generator Room, showing electromagnetic pulse (EMP) filter boxes ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Looking into Generator Room, showing electromagnetic pulse (EMP) filter boxes mounted above door - Beale Air Force Base, Perimeter Acquisition Vehicle Entry Phased-Array Warning System, Power Plant, End of Spencer Paul Road, north of Warren Shingle Road (14th Street), Marysville, Yuba County, CA

9 CFR 318.305 - Equipment and procedures for heat processing systems.

Code of Federal Regulations, 2011 CFR

2011-01-01

... ensure a supply of clean, dry air. The recorder timing mechanism shall be accurate. (i) Chart-type... filter systems to ensure a supply of clean, dry air. (ii) Pressure recording device. Each retort shall be... section. (2) Cooling canal water shall be chlorinated or treated with a chemical approved by the...

9 CFR 381.305 - Equipment and procedures for heat processing systems.

Code of Federal Regulations, 2011 CFR

2011-01-01

... supply of clean, dry air. The recorder timing mechanism shall be accurate. (i) Chart-type devices... filter systems to ensure a supply of clean, dry air. (ii) Pressure recording device. Each retort shall be... cooling except as provided for in paragraphs (h) (2) and (3) of this section. (2) Cooling canal water...

Experimental investigation of air pressure affecting filtration performance of fibrous filter sheet.

PubMed

Xu, Bin; Yu, Xiao; Wu, Ya; Lin, Zhongping

2017-03-01

Understanding the effect of air pressure on their filtration performance is important for assessing the effectiveness of fibrous filters under different practical circumstances. The effectiveness of three classes of air filter sheets were investigated in laboratory-based measurements at a wide range of air pressures (60-130 KPa). The filtration efficiency was found most sensitive to the air pressure change at smaller particle sizes. As the air pressure increased from 60 to 130 KPa, significant decrease in filtration efficiency (up to 15%) and increase in pressure drop (up to 90 Pa) were observed. The filtration efficiency of the filter sheet with largest fiber diameter and smallest solid volume fraction was affected most, while the pressure drop of the filter sheet with smallest fiber diameter and largest solid volume fraction was affected most. The effect of air pressure on the filtration efficiency was slightly larger at greater filter face air velocity. However, the effect of air pressure on the pressure drop was negligible. The filtration efficiency and pressure drop were explicitly expressed as functions of the air pressure. Two coefficients were empirically derived and successfully accounted for the effects of air pressure on filtration efficiency and pressure drop.

Two New Pieces of Emergency Response Equipment for use in Confined Space Environments

NASA Technical Reports Server (NTRS)

Graf, John

2011-01-01

NASA is developing two new pieces of emergency response equipment that recognize and address the constraints of a confined space environment. One piece of equipment is a respirator designed for use in a post fire environment. Traditional first responders generally use supplied air respirators - they provide cool, dry, safe breathing air to the first responder, and because they are supplied at above ambient pressure, the system is tolerant to a loose-fitting mask. Supplied air respirators have a limited supply of air, but because the traditional first responder intends to address the emergency from outside and then retreat, this limited air supply does not pose a serious problem. NASA uses a supplied oxygen respirator for first response to an emergency affecting air quality on the International Space Station. The air supply is rated for 15 minutes - ISS program managers sponsored a hardware development activity to provide the astronauts up to 8 hours of breathing protection after the supplied air system is exhausted. Size and weight limitations prevent the use of a supplied air system for 8 hours for six crew members. A trade study resulted in the selection of a filtering respirator system over a re-breather system; due to design simplicity, operational simplicity, and likely threats to air quality on ISS. The respirator cartridge that filters smoke particles, adsorbs organics and acid gases, and catalytically converts carbon monoxide to carbon dioxide has been qualified for use on ISS, and was delivered on STS-135, the final mission of the Space Shuttle Program.

Further evaluation of alternative air-filtration systems for reducing the transmission of Porcine reproductive and respiratory syndrome virus by aerosol

PubMed Central

Deen, John; Cano, Jean Paul; Batista, Laura; Pijoan, Carlos

2006-01-01

Abstract The purpose of this study was to compare 4 methods for the reduction of aerosol transmission of Porcine reproductive and respiratory syndrome virus (PRRSV): high-efficiency particulate air (HEPA) filtration, 2×-low-cost filtration, bag filtration, and use of a filter tested against particles derived from dioctylphthalate (DOP). The HEPA-filtration system used a prefilter screen, a bag filter (Eurovent [EU] 8 rating), and a HEPA filter (EU13 rating). The low-cost-filtration system contained mosquito netting (prefilter), 2 fiberglass furnace filters, and 2 electrostatic furnace filters. Bag filtration involved the use of a filter rated EU8 and a minimum efficiency reporting value (MERV) of 14. The 95%-DOP, 0.3-μm-filtration system involved a pleat-in-pleat V-bank disposable filter with a 95% efficiency rating for particles 0.3 μm or greater in diameter and ratings of EU9 and MERV 15. No form of intervention was used in the control group. The experimental facilities consisted of 2 chambers connected by a 1.3-m-long duct containing the treatments. Recipient pigs, housed in chamber 2, were exposed to artificial aerosols created by a mechanically operated mister containing modified live PRRSV vaccine located in chamber 1. Aerosol transmission of PRRSV occurred in 0 of the 10 HEPA-filtration replicates, 2 of the 10 bag-filtration replicates, 4 of the 10 low-cost-filtration replicates, 0 of the 10 95%-DOP, 0.3-μm-filtration replicates, and all 10 of the control replicates. Using a similar approach, we further evaluated the HEPA- and 95%-DOP, 0.3-μm-filtration systems. Infection was not observed in any of the 76 HEPA-filtration replicates but was observed in 2 of the 76 95%-DOP, 0.3-μm replicates and 42 of the 50 control replicates. Although the difference between the 95%-DOP, 0.3-μm and control replicates was significant (P < 0.0005), so was the level of failure of the 95%-DOP, 0.3-μm system (P = 0.02). In conclusion, under the conditions of this study, some methods of air filtration were significantly better than others in reducing aerosol transmission of PRRSV, and HEPA filtration was the only system that completely prevented transmission. PMID:16850938

Use of Whatman-41 filters in air quality sampling networks (with applications to elemental analysis)

NASA Technical Reports Server (NTRS)

Neustadter, H. E.; Sidik, S. M.; King, R. B.; Fordyce, J. S.; Burr, J. C.

1974-01-01

The operation of a 16-site parallel high volume air sampling network with glass fiber filters on one unit and Whatman-41 filters on the other is reported. The network data and data from several other experiments indicate that (1) Sampler-to-sampler and filter-to-filter variabilities are small; (2) hygroscopic affinity of Whatman-41 filters need not introduce errors; and (3) suspended particulate samples from glass fiber filters averaged slightly, but not statistically significantly, higher than from Whatman-41-filters. The results obtained demonstrate the practicability of Whatman-41 filters for air quality monitoring and elemental analysis.

Innovative Monitoring of Atmospheric Gaseous Hydrogen Fluoride

PubMed Central

Bonari, Alessandro; Pompilio, Ilenia; Monti, Alessandro; Arcangeli, Giulio

2016-01-01

Hydrogen fluoride (HF) is a basic raw material for a wide variety of industrial products, with a worldwide production capacity of more than three million metric tonnes. A novel method for determining particulate fluoride and gaseous hydrogen fluoride in air is presented herewith. Air was sampled using miniaturised 13 mm Swinnex two-stage filter holders in a medium-flow pumping system and through the absorption of particulate fluoride and HF vapours on cellulose ester filters uncoated or impregnated with sodium carbonate. Furthermore, filter desorption from the holders and the extraction of the pentafluorobenzyl ester derivative based on solid-phase microextraction were performed using an innovative robotic system installed on an xyz autosampler on-line with gas chromatography (GC)/mass spectrometry (MS). After generating atmospheres of a known concentration of gaseous HF, we evaluated the agreement between the results of our sampling method and those of the conventional preassembled 37 mm cassette (±8.10%; correlation coefficient: 0.90). In addition, precision (relative standard deviation for n = 10, 4.3%), sensitivity (0.2 μg/filter), and linearity (2.0–4000 μg/filter; correlation coefficient: 0.9913) were also evaluated. This procedure combines the efficiency of GC/MS systems with the high throughput (96 samples/day) and the quantitative accuracy of pentafluorobenzyl bromide on-sample derivatisation. PMID:27829835

Building the Brain's "Air Traffic Control" System: How Early Experiences Shape the Development of Executive Function. Working Paper 11

ERIC Educational Resources Information Center

National Scientific Council on the Developing Child, 2011

2011-01-01

Being able to focus, hold, and work with information in mind, filter distractions, and switch gears is like having an air traffic control system at a busy airport to manage the arrivals and departures of dozens of planes on multiple runways. In the brain, this air traffic control mechanism is called executive functioning, a group of skills that…

Joint Service Chemical and Biological Defense Program FY 08-09 Overview

DTIC Science & Technology

2007-10-01

of human plasma-derived butyrylcholinesterase Electronmicrograph of bacillus spores adhering to cell membrane processes Jo i n t Se rv i c e ch e m i...human performance within CB-protective systems. Carbon monolith for electro-swing adsorption Bacillus globigii spores collecting on an...integrated with the ship’s heating, ventilation, and air-conditioning ( HVAC ) systems and provides a filter air supply air for overpressurization of

Air filtration in the free molecular flow regime: a review of high-efficiency particulate air filters based on carbon nanotubes.

PubMed

Li, Peng; Wang, Chunya; Zhang, Yingying; Wei, Fei

2014-11-01

Air filtration in the free molecular flow (FMF) regime is important and challenging because a higher filtration efficiency and lower pressure drop are obtained when the fiber diameter is smaller than the gas mean free path in the FMF regime. In previous studies, FMF conditions have been obtained by increasing the gas mean free path through reducing the pressure and increasing the temperature. In the case of carbon nanotubes (CNTs) with nanoscale diameters, it is possible to filtrate in the FMF regime under normal conditions. This paper reviews recent progress in theoretical and experimental studies of air filtration in the FMF regime. Typical structure models of high-efficiency particulate (HEPA) air filters based on CNTs are introduced. The pressure drop in air filters operated in the FMF regime is less than that predicted by the conventional air filtration theory. The thinnest HEPA filters fabricated from single-walled CNT films have an extremely low pressure drop. CNT air filters with a gradient nanostructure are shown to give a much better filtration performance in dynamic filtration. CNT air filters with a hierarchical structure and an agglomerated CNT fluidized bed air filter are also introduced. Finally, the challenges and opportunities for the application of CNTs in air filtration are discussed. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bio-Defense Now: 56 Suggestions for Immediate Improvements

DTIC Science & Technology

2005-05-01

Air Education and Training Command HVAC Heating, Ventilation and Air Conditioning ICAM Improved Chemical Agent Monitor ICD-9-CM Internal...conditioning ( HVAC ) system capabilities, making a big difference in removal of many BW agents. High Efficiency Particulate Air (HEPA) filters are also...agents. This program has developed biological sensor-activated heating, ventilation, and air conditioning ( HVAC ) control sys- tems, high efficiency

Analysis of On-Board Oxygen and Nitrogen Generation Systems for Surface Vessels.

DTIC Science & Technology

1983-06-01

and Pressure Vessel Code SAE AIR 822 Oxygen for General Aviation Aircraft SAE AIR 825 Oxygen for Aircrafts SAE AIR 1059 Transportation and Maintenance...OF THE TITLE MIL-T-27730 Threaded Components MIL-P-27401 A 40 Micron Filter For Nitrogen MIL-V-33650 Internal Straight Threads ASME Code VIII Boiler

Atmospheric pollutants and trace gases

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

Ranieri, A.; Schenone, G.; Lencioni, L.

1994-03-01

Pumpkin [Cucurbita pepo (L.) cv. Ambassador] plants were grown under either nonfiltered or filtered ambient air in open-top field chambers (OTCs) near the urban area of Milan, Northern Italy. The effects of ambient air pollution on the enzymatic detoxfication system of the leaves, both in terms of activity and isoform pattern were investigated. The data on air quality showed that ozone was the main phytotoxic pollutant present in ambient air, reaching a 7 h mean of 63 nL L{sup -1} and a maximum hourly peak of 104 nL L{sup -1} The peroxidase and catalase activities increased fourfold and twofold, respectivelymore » in the nonfiltered air plants In comparison to the filtered air ones. The peroxidase patterns were very modified in the polluted plants. In contrast no significant changes were found in the activity and isoenzyme pattern of superoxide dismutase. The data reported here suggest that in field-grown pumpkin plants exposed to ambient levels of photooxidants, a stimulation of the peroxddase-catalase detoxification system takes place. 32 refs., 3 figs., 3 tabs.« less

Fan filter cleaning on the CHeCS AAA in the US Lab

NASA Image and Video Library

2009-05-05

ISS019-E-013710 (5 May 2009) --- Japan Aerospace Exploration Agency (JAXA) astronaut Koichi Wakata, Expedition 19/20 flight engineer, cleans a fan filter on the Crew Health Care System Avionics Air Assembly (CHeCS AAA) in the Destiny laboratory of the International Space Station.

ENVIRONMENTAL TECHNOLOGY VERIFICATION, TEST REPORT OF CONTROL OF BIOAEROSOLS IN HVAC SYSTEMS, AIRFLOW PRODUCTS AFP30

EPA Science Inventory

The Environmental Technology Verification report discusses the technology and performance of the AFP30 air filter for dust and bioaerosol filtration manufactured by Airflow Products. The pressure drop across the filter was 62 Pa clean and 247 Pa dust loaded. The filtration effici...

Unmanned. Evaluation of Bauer High Pressure Breathing Air P-5 Purification System

DTIC Science & Technology

1991-08-01

suspended in the compressed air . The molecular sieve is made to adsorb oil and water vapors. The second cylinder uses cartridge No. 058825 and is a...during compressor start up. This provides for optimum filtering, moisture separation and prevents compressed air return from the charged air storage...reciprocating, air -cooled unit. The compressor is rated to deliver 20 cfm of free air compressed to 5000 psig. - .. .. . .. ’,= .• .. . .. . -. . I

Method and apparatus for reducing cold-phase emissions by utilizing oxygen-enriched intake air

DOEpatents

Poola, Ramesh B.; Sekar, Ramanujam R.; Stork, Kevin C.

1997-01-01

An oxygen-enriched air intake control system for an internal combustion engine includes air directing apparatus to control the air flow into the intake of the engine. During normal operation of the engine, ambient air flowing from an air filter of the engine flows through the air directing apparatus into the intake of the engine. In order to decrease the amount of carbon monoxide (CO) and hydrocarbon (HC) emissions that tend to be produced by the engine during a short period of time after the engine is started, the air directing apparatus diverts for a short period of time following the start up of the engine at least a portion of the ambient air from the air filter through a secondary path. The secondary path includes a selectively permeable membrane through which the diverted portion of the ambient air flows. The selectively permeable membrane separates nitrogen and oxygen from the diverted air so that oxygen enriched air containing from about 23% to 25% oxygen by volume is supplied to the intake of the engine.

Effect of filter on average glandular dose and image quality in digital mammography

NASA Astrophysics Data System (ADS)

Songsaeng, C.; Krisanachinda, A.; Theerakul, K.

2016-03-01

To determine the average glandular dose and entrance surface air kerma in both phantoms and patients to assess image quality for different target-filters (W/Rh and W/Ag) in digital mammography system. The compressed breast thickness, compression force, average glandular dose, entrance surface air kerma, peak kilovoltage and tube current time were recorded and compared between W/Rh and W/Ag target filter. The CNR and the figure of merit were used to determine the effect of target filter on image quality. The mean AGD of the W/Rh target filter was 1.75 mGy, the mean ESAK was 6.67 mGy, the mean CBT was 54.1 mm, the mean CF was 14 1bs. The mean AGD of W/Ag target filter was 2.7 mGy, the mean ESAK was 12.6 mGy, the mean CBT was 75.5 mm, the mean CF was 15 1bs. In phantom study, the AGD was 1.2 mGy at 4 cm, 3.3 mGy at 6 cm and 3.83 mGy at 7 cm thickness. The FOM was 24.6, CNR was 9.02 at thickness 6 cm. The FOM was 18.4, CNR was 8.6 at thickness 7 cm. The AGD from Digital Mammogram system with W/Rh of thinner CBT was lower than the AGD from W/Ag target filter.

42 CFR 84.170 - Non-powered air-purifying particulate respirators; description.

Code of Federal Regulations, 2013 CFR

2013-10-01

... inhalation pressure to draw the ambient air through the air-purifying filter elements (filters) to remove... classified into three series, N-, R-, and P-series. The N-series filters are restricted to use in those workplaces free of oil aerosols. The R- and P-series filters are intended for removal of any particulate that...

42 CFR 84.170 - Non-powered air-purifying particulate respirators; description.

Code of Federal Regulations, 2011 CFR

2011-10-01

... inhalation pressure to draw the ambient air through the air-purifying filter elements (filters) to remove... classified into three series, N-, R-, and P-series. The N-series filters are restricted to use in those workplaces free of oil aerosols. The R- and P-series filters are intended for removal of any particulate that...

42 CFR 84.170 - Non-powered air-purifying particulate respirators; description.

Code of Federal Regulations, 2014 CFR

2014-10-01

... inhalation pressure to draw the ambient air through the air-purifying filter elements (filters) to remove... classified into three series, N-, R-, and P-series. The N-series filters are restricted to use in those workplaces free of oil aerosols. The R- and P-series filters are intended for removal of any particulate that...

42 CFR 84.170 - Non-powered air-purifying particulate respirators; description.

Code of Federal Regulations, 2012 CFR

2012-10-01

... inhalation pressure to draw the ambient air through the air-purifying filter elements (filters) to remove... classified into three series, N-, R-, and P-series. The N-series filters are restricted to use in those workplaces free of oil aerosols. The R- and P-series filters are intended for removal of any particulate that...

42 CFR 84.170 - Non-powered air-purifying particulate respirators; description.

Code of Federal Regulations, 2010 CFR

2010-10-01

... inhalation pressure to draw the ambient air through the air-purifying filter elements (filters) to remove... classified into three series, N-, R-, and P-series. The N-series filters are restricted to use in those workplaces free of oil aerosols. The R- and P-series filters are intended for removal of any particulate that...

Evaluation of BAUER UTILUS 10 and TRIPLEX Purification Systems

DTIC Science & Technology

1993-08-01

of the test was to: A. Determine if the compressor and Purification System provides compressed air at the required pressures, flow rates, quality and...optimum filtering, moisture separation, third stage piston ring expansion/cylinder sealing and prevents compressed air return from the storage flasks to the...551 COMPRESSED AIR PLANTS AND SYSTEMS S9086-SY-STM-O0O PARA 551-4.2.2.1. 6. Navy Experimental Diving Unit Test Plan Number 93-01, Jan 93. 7. NAVSEAINST

Assessment of zero-equation SGS models for simulating indoor environment

NASA Astrophysics Data System (ADS)

Taghinia, Javad; Rahman, Md Mizanur; Tse, Tim K. T.

2016-12-01

The understanding of air-flow in enclosed spaces plays a key role to designing ventilation systems and indoor environment. The computational fluid dynamics aspects dictate that the large eddy simulation (LES) offers a subtle means to analyze complex flows with recirculation and streamline curvature effects, providing more robust and accurate details than those of Reynolds-averaged Navier-Stokes simulations. This work assesses the performance of two zero-equation sub-grid scale models: the Rahman-Agarwal-Siikonen-Taghinia (RAST) model with a single grid-filter and the dynamic Smagorinsky model with grid-filter and test-filter scales. This in turn allows a cross-comparison of the effect of two different LES methods in simulating indoor air-flows with forced and mixed (natural + forced) convection. A better performance against experiments is indicated with the RAST model in wall-bounded non-equilibrium indoor air-flows; this is due to its sensitivity toward both the shear and vorticity parameters.

Evaluation of a commercial air filter for removal of viruses from the air.

PubMed

Roelants, P; Boon, B; Lhoest, W

1968-10-01

The effectiveness of a commercial absolute air filter for removal of viruses from air was tested with an actinophage, under the usual conditions of a laminar airflow clean room. A new method of dry phage dispersion is described. The filter showed an average reduction of 99.996% of airborne actinophage.

40 CFR 63.11468 - What are the monitoring requirements for new and existing sources?

Code of Federal Regulations, 2011 CFR

2011-07-01

... baghouse, including but not limited to air leaks, torn or broken bags or filter media, or any other...) Inspecting the fabric filter for air leaks, torn or broken bags or filter media, or any other condition that... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR...

40 CFR 63.11468 - What are the monitoring requirements for new and existing sources?

Code of Federal Regulations, 2013 CFR

2013-07-01

... baghouse, including but not limited to air leaks, torn or broken bags or filter media, or any other...) Inspecting the fabric filter for air leaks, torn or broken bags or filter media, or any other condition that... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR...

40 CFR 63.11468 - What are the monitoring requirements for new and existing sources?

Code of Federal Regulations, 2012 CFR

2012-07-01

... baghouse, including but not limited to air leaks, torn or broken bags or filter media, or any other...) Inspecting the fabric filter for air leaks, torn or broken bags or filter media, or any other condition that... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR...

40 CFR 63.11468 - What are the monitoring requirements for new and existing sources?

Code of Federal Regulations, 2014 CFR

2014-07-01

... baghouse, including but not limited to air leaks, torn or broken bags or filter media, or any other...) Inspecting the fabric filter for air leaks, torn or broken bags or filter media, or any other condition that... PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR...

Near-infrared spectroscopy (NIRS) as a tool to monitor exhaust air from poultry operations.

PubMed

Druckenmüller, Katharina; Günther, Klaus; Elbers, Gereon

2018-07-15

Intensive poultry operation systems emit a considerable volume of inorganic and organic matter in the surrounding environment. Monitoring cleaning properties of exhaust air cleaning systems and to detect small but significant changes in emission characteristics during a fattening cycle is important for both emission and fattening process control. In the present study, we evaluated the potential of near-infrared spectroscopy (NIRS) combined with chemometric techniques as a monitoring tool of exhaust air from poultry operation systems. To generate a high-quality data set for evaluation, the exhaust air of two poultry houses was sampled by applying state-of-the-art filter sampling protocols. The two stables were identical except for one crucial difference, the presence or absence of an exhaust air cleaning system. In total, twenty-one exhaust air samples were collected at the two sites to monitor spectral differences caused by the cleaning device, and to follow changes in exhaust air characteristics during a fattening period. The total dust load was analyzed by gravimetric determination and included as a response variable in multivariate data analysis. The filter samples were directly measured with NIR spectroscopy. Principal component analysis (PCA), linear discriminant analysis (LDA), and factor analysis (FA) were effective in classifying the NIR exhaust air spectra according to fattening day and origin. The results indicate that the dust load and the composition of exhaust air (inorganic or organic matter) substantially influence the NIR spectral patterns. In conclusion, NIR spectroscopy as a tool is a promising and very rapid way to detect differences between exhaust air samples based on still not clearly defined circumstances triggered during a fattening period and the availability of an exhaust air cleaning system. Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.

A CAM (continuous air monitor) sampler for collecting and assessing alpha-emitting aerosol particles

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

McFarland, A.R.; Bethel, E.L.; Ortiz, C.A.

1991-07-01

A new continuous air monitor (CAM) sampler for assessing alpha-emitting transuranic aerosol particles has been developed. The system has been designed to permit collection of particles that can potentially penetrate into the thoracic region of the human respiratory system. Wind tunnel testing of the sampler has been used to characterize the penetration of aerosol to the collection filter. Results show that greater than or equal to 50% of 10-micrograms aerodynamic equivalent diameter (AED) particles are collected by the filter at wind speeds of 0.3 to 2 m s-1 and at sampling flow rates of 28 to 113 L min-1 (1more » to 4 cfm). The deposition of 10-microns AED particles takes place primarily in the center of the filter, where the counting efficiency of the detector is highest.« less

Particle loading rates for HVAC filters, heat exchangers, and ducts.

PubMed

Waring, M S; Siegel, J A

2008-06-01

The rate at which airborne particulate matter deposits onto heating, ventilation, and air-conditioning (HVAC) components is important from both indoor air quality (IAQ) and energy perspectives. This modeling study predicts size-resolved particle mass loading rates for residential and commercial filters, heat exchangers (i.e. coils), and supply and return ducts. A parametric analysis evaluated the impact of different outdoor particle distributions, indoor emission sources, HVAC airflows, filtration efficiencies, coils, and duct system complexities. The median predicted residential and commercial loading rates were 2.97 and 130 g/m(2) month for the filter loading rates, 0.756 and 4.35 g/m(2) month for the coil loading rates, 0.0051 and 1.00 g/month for the supply duct loading rates, and 0.262 g/month for the commercial return duct loading rates. Loading rates are more dependent on outdoor particle distributions, indoor sources, HVAC operation strategy, and filtration than other considered parameters. The results presented herein, once validated, can be used to estimate filter changing and coil cleaning schedules, energy implications of filter and coil loading, and IAQ impacts associated with deposited particles. The results in this paper suggest important factors that lead to particle deposition on HVAC components in residential and commercial buildings. This knowledge informs the development and comparison of control strategies to limit particle deposition. The predicted mass loading rates allow for the assessment of pressure drop and indoor air quality consequences that result from particle mass loading onto HVAC system components.

DEVELOPMENT OF AG-1 SECTION FI ON METAL MEDIA FILTERS - 9061

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

Adamson, D; Charles A. Waggoner, C

Development of a metal media standard (FI) for ASME AG-1 (Code on Nuclear Air and Gas Treatment) has been under way for almost ten years. This paper will provide a brief history of the development process of this section and a detailed overview of its current content/status. There have been at least two points when dramatic changes have been made in the scope of the document due to feedback from the full Committee on Nuclear Air and Gas Treatment (CONAGT). Development of the proposed section has required resolving several difficult issues associated with scope; namely, filtering efficiency, operating conditions (mediamore » velocity, pressure drop, etc.), qualification testing, and quality control/acceptance testing. A proposed version of Section FI is currently undergoing final revisions prior to being submitted for balloting. The section covers metal media filters of filtering efficiencies ranging from medium (less than 99.97%) to high (99.97% and greater). Two different types of high efficiency filters are addressed; those units intended to be a direct replacement of Section FC fibrous glass HEPA filters and those that will be placed into newly designed systems capable of supporting greater static pressures and differential pressures across the filter elements. Direct replacements of FC HEPA filters in existing systems will be required to meet equivalent qualification and testing requirements to those contained in Section FC. A series of qualification and quality assurance test methods have been identified for the range of filtering efficiencies covered by this proposed standard. Performance characteristics of sintered metal powder vs. sintered metal fiber media are dramatically different with respect to parameters like differential pressures and rigidity of the media. Wide latitude will be allowed for owner specification of performance criteria for filtration units that will be placed into newly designed systems. Such allowances will permit use of the most appropriate metal media for a system as specified by the owner with respect to material of manufacture, media velocity, system maximum static pressure, maximum differential pressure across the filter, and similar parameters.« less

Bioaerosol DNA Extraction Technique from Air Filters Collected from Marine and Freshwater Locations

NASA Astrophysics Data System (ADS)

Beckwith, M.; Crandall, S. G.; Barnes, A.; Paytan, A.

2015-12-01

Bioaerosols are composed of microorganisms suspended in air. Among these organisms include bacteria, fungi, virus, and protists. Microbes introduced into the atmosphere can drift, primarily by wind, into natural environments different from their point of origin. Although bioaerosols can impact atmospheric dynamics as well as the ecology and biogeochemistry of terrestrial systems, very little is known about the composition of bioaerosols collected from marine and freshwater environments. The first step to determine composition of airborne microbes is to successfully extract environmental DNA from air filters. We asked 1) can DNA be extracted from quartz (SiO2) air filters? and 2) how can we optimize the DNA yield for downstream metagenomic sequencing? Aerosol filters were collected and archived on a weekly basis from aquatic sites (USA, Bermuda, Israel) over the course of 10 years. We successfully extracted DNA from a subsample of ~ 20 filters. We modified a DNA extraction protocol (Qiagen) by adding a beadbeating step to mechanically shear cell walls in order to optimize our DNA product. We quantified our DNA yield using a spectrophotometer (Nanodrop 1000). Results indicate that DNA can indeed be extracted from quartz filters. The additional beadbeating step helped increase our yield - up to twice as much DNA product was obtained compared to when this step was omitted. Moreover, bioaerosol DNA content does vary across time. For instance, the DNA extracted from filters from Lake Tahoe, USA collected near the end of June decreased from 9.9 ng/μL in 2007 to 3.8 ng/μL in 2008. Further next-generation sequencing analysis of our extracted DNA will be performed to determine the composition of these microbes. We will also model the meteorological and chemical factors that are good predictors for microbial composition for our samples over time and space.

40 CFR 204.55-3 - Configuration identification.

Code of Federal Regulations, 2010 CFR

2010-07-01

... PROGRAMS NOISE EMISSION STANDARDS FOR CONSTRUCTION EQUIPMENT Portable Air Compressors § 204.55-3... the following parameters: (1) The compressor type (screw, sliding vane, etc.). (2) Number of compressor stages. (3) Maximum pressure (psi). (4) Air intake system of compressor: (i) Number of filters...

Air-Gapped Structures as Magnetic Elements for Use in Power Processing Systems. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Ohri, A. K.

1977-01-01

Methodical approaches to the design of inductors for use in LC filters and dc-to-dc converters using air gapped magnetic structures are presented. Methods for the analysis and design of full wave rectifier LC filter circuits operating with the inductor current in both the continuous conduction and the discontinuous conduction modes are also described. In the continuous conduction mode, linear circuit analysis techniques are employed, while in the case of the discontinuous mode, the method of analysis requires computer solutions of the piecewise linear differential equations which describe the filter in the time domain. Procedures for designing filter inductors using air gapped cores are presented. The first procedure requires digital computation to yield a design which is optimized in the sense of minimum core volume and minimum number of turns. The second procedure does not yield an optimized design as defined above, but the design can be obtained by hand calculations or with a small calculator. The third procedure is based on the use of specially prepared magnetic core data and provides an easy way to quickly reach a workable design.

Magnetic analyses of powders from exhausted cabin air filters

NASA Astrophysics Data System (ADS)

Winkler, Aldo; Sagnotti, Leonardo

2013-04-01

The automotive cabin air filter is a pleated-paper filter placed in the outside-air intake for the car's passenger compartment. Dirty and saturated cabin air filters significantly reduce the airflow from the outside and introduce particulate matter (PM) and allergens (for example, pollen) into the cabin air stream. Magnetic measurements and analyses have been carried out on powders extracted from exhausted cabin air filters to characterize their magnetic properties and to compare them to those already reported for powders collected from disk brakes, gasoline exhaust pipes and Quercus ilex leaves. This study is also aimed at the identification and quantification of the contribution of the ultrafine fraction, superparamagnetic (SP) at room temperature, to the overall magnetic properties of these powders. This contribution was estimated by interpreting and comparing data from FORCs, isothermal remanent magnetization vs time decay curves, frequency and field dependence of the magnetic susceptibility and out-of-phase susceptibility. The magnetic properties and the distribution of the SP particles are generally homogenous and independent of the brand of the car, of the model of the filter and of its level of usage. The relatively high concentration of magnetic PM trapped in these filters poses relevant questions about the air quality inside a car.

Detection of respiratory viruses on air filters from aircraft.

PubMed

Korves, T M; Johnson, D; Jones, B W; Watson, J; Wolk, D M; Hwang, G M

2011-09-01

To evaluate the feasibility of identifying viruses from aircraft cabin air, we evaluated whether respiratory viruses trapped by commercial aircraft air filters can be extracted and detected using a multiplex PCR, bead-based assay. The ResPlex II assay was first tested for its ability to detect inactivated viruses applied to new filter material; all 18 applications of virus at a high concentration were detected. The ResPlex II assay was then used to test for 18 respiratory viruses on 48 used air filter samples from commercial aircraft. Three samples tested positive for viruses, and three viruses were detected: rhinovirus, influenza A and influenza B. For 33 of 48 samples, internal PCR controls performed suboptimally, suggesting sample matrix effect. In some cases, influenza and rhinovirus RNA can be detected on aircraft air filters, even more than 10 days after the filters were removed from aircraft. With protocol modifications to overcome PCR inhibition, air filter sampling and the ResPlex II assay could be used to characterize viruses in aircraft cabin air. Information about viruses in aircraft could support public health measures to reduce disease transmission within aircraft and between cities. © The MITRE corporation. Letters in Applied Microbiology © 2011 The Society for Applied Microbiology.

Evaluation of a Commercial Air Filter for Removal of Virus from the Air

PubMed Central

Roelants, P.; Boon, B.; Lhoest, W.

1968-01-01

The effectiveness of a commercial absolute air filter for removal of viruses from air was tested with an actinophage, under the usual conditions of a laminar airflow clean room. A new method of dry phage dispersion is described. The filter showed an average reduction of 99.996% of airborne actinophage. PMID:5684200

Exploring Potential ADS-B Vulnerabilites in the FAA’s Nextgen Air Transportation System

DTIC Science & Technology

2011-06-01

an online database of aircraft and the camera is used to filter the data, based on field of view, for display on the phone’s screen. The developers...34 December 28, 2009. [Online]. abcnews.go.com [5] P. Dempsey and L. Gesell , Air Transportation: Foundations for the 21st Century. Arizona: Coast Aire

Design of a small personal air monitor and its application in aircraft.

PubMed

van Netten, Chris

2009-01-15

A small air sampling system using standard air filter sampling technology has been used to monitor the air in aircraft. The device is a small ABS constructed cylinder 5 cm in diameter and 9 cm tall and can be operated by non technical individuals at an instant notice. It is completely self contained with a 4 AAA cell power supply, DC motor, a centrifugal fan, and accommodates standard 37 mm filters and backup pads. The monitor is totally enclosed and pre assembled in the laboratory. A 45 degrees twist of the cap switches on the motor and simultaneously opens up the intake ports and exhaust ports allowing air to pass through the filter. A reverse 45 degrees twist of the cap switches off the motor and closes all intake and exhaust ports, completely enclosing the filter. The whole monitor is returned to the laboratory by standard mail for analysis and reassembly for future use. The sampler has been tested for electromagnetic interference and has been approved for use in aircraft during all phases of flight. A set of samples taken by a BAe-146-300 crew member during two flights in the same aircraft and analyzed by GC-MS, indicated exposure to tricresyl phosphate (TCP) levels ranging from 31 to 83 nanograms/m(3) (detection limit <4.5 nanograms/m(3)). The latter elevated level was associated with the use of the auxiliary power unit (APU) in the aircraft. It was concluded that the air sampler was capable of monitoring air concentrations of TCP isomers in aircraft above 4.5 nanogram/m(3).

The effectiveness of stand alone air cleaners for shelter-in-place.

PubMed

Ward, M; Siegel, J A; Corsi, R L

2005-04-01

Stand-alone air cleaners may be efficient for rapid removal of indoor fine particles and have potential use for shelter-in-place (SIP) strategies following acts of bioterrorism. A screening model was employed to ascertain the potential significance of size-resolved particle (0.1-2 microm) removal using portable high efficiency particle arresting (HEPA) air cleaners in residential buildings following an outdoor release of particles. The number of stand-alone air cleaners, air exchange rate, volumetric flow rate through the heating, ventilating and air-conditioning (HVAC) system, and size-resolved particle removal efficiency in the HVAC filter were varied. The effectiveness of air cleaners for SIP was evaluated in terms of the outdoor and the indoor particle concentration with air cleaner(s) relative to the indoor concentration without air cleaners. Through transient and steady-state analysis of the model it was determined that one to three portable HEPA air cleaners can be effective for SIP following outdoor bioaerosol releases, with maximum reductions in particle concentrations as high as 90% relative to conditions in which an air cleaner is not employed. The relative effectiveness of HEPA air cleaners vs. other removal mechanisms was predicted to decrease with increasing particle size, because of increasing competition by particle deposition with indoor surfaces and removal to HVAC filters. However, the effect of particle size was relatively small for most scenarios considered here. The results of a screening analysis suggest that stand-alone (portable) air cleaners that contain high efficiency particle arresting (HEPA) filters can be effective for reducing indoor fine particle concentrations in residential dwellings during outdoor releases of biological warfare agents. The relative effectiveness of stand-alone air cleaners for reducing occupants' exposure to particles of outdoor origin depends on several factors, including the type of heating, ventilating and air-conditioning (HVAC) filter, HVAC operation, building air exchange rate, particle size, and duration of elevated outdoor particle concentration. Maximum particle reductions, relative to no stand-alone air cleaners, of 90% are predicted when three stand-alone air cleaners are employed.

Filter aids influence on pressure drop across a filtration system

NASA Astrophysics Data System (ADS)

Hajar, S.; Rashid, M.; Nurnadia, A.; Ammar, M. R.; Hasfalina, C. M.

2017-06-01

Filter aids is commonly used to reduce pressure drop across air filtration system as it helps to increase the efficiency of filtration of accumulated filter cake. Filtration velocity is one of the main parameters that affect the performance of filter aids material. In this study, a formulated filter aids consisting of PreKot™ and activated carbon mixture (designated as PrekotAC) was tested on PTFE filter media under various filtration velocities of 5, 6, and 8 m/min at a constant material loading of 0.2 mg/mm2. Results showed that pressure drop is highly influenced by filtration velocity where higher filtration velocity leads to a higher pressure drop across the filter cake. It was found that PrekotAC performed better in terms of reducing the pressure drop across the filter cake even at the highest filtration velocity. The diversity in different particle size distribution of non-uniform particle size in the formulated PrekotAC mixture presents a higher permeability causes a lower pressure drop across the accumulated filter cake. The finding suggests that PrekotAC is a promising filter aids material that helps reducing the pressure drop across fabric filtration system.

Nonwoven Fabric Uses and Prospects in Human Space Flight

NASA Technical Reports Server (NTRS)

Bacon, Jack

2001-01-01

The US space shuttle fleet has been flying for over 20 years. Although the shuttle operates in a unique exterior environment, the interior is intentionally made to be as close to the "normal" human environment as possible. The filtration needs of the shuttle are not substantially different from those of a large mobile home or camper, supporting the needs of a family of seven for up to two weeks. Therefore, most of the materials that are used to filter the air, water, and other fluids on the Shuttle are similar or identical to those employed in other sectors of the transportation industry. The only significantly different feature of the space environment is the unique "three-phase" nature of the air (with suspended liquids and solids ranging in size from aerosol droplets to binoculars). Such suspended debris contributes to the air filtration and waste management problem. Careful flow management and cleanliness practices help to mitigate the effect of debris, and liquid spills are rare, seldom making it to the filters. (It has been common on all spacecraft to look first for lost items on the air intake filters, since all objects ultimately migrate there in the flow. Liquids tend to seep rather than "spill", and so tend to aggregate in a ball near the source.) In addition to the basic fluids of the interior environment (water and water wastes, air, and its constituent supply gasses) the shuttle also has unfiltered fluid systems for Freon, hydrogen, helium, ammonia, hydraulic fluid, and propellants. Only the propellant system, owing to its uncommon chemistry, represents a fluid system that is not typical of household or medical applications. Careful external filtration prior to flight assures the cleanliness in these closed systems.

Quantification of the fungal fraction released from various preloaded fibrous filters during a simulated ventilation restart.

PubMed

Morisseau, K; Joubert, A; Le Coq, L; Andres, Y

2017-05-01

This study aimed to demonstrate that particles, especially those associated with fungi, could be released from fibrous filters used in the air-handling unit (AHU) of heating, ventilation and air-conditioning (HVAC) systems during ventilation restarts. Quantification of the water retention capacity and SEM pictures of the filters was used to show the potential for fungal proliferation in unused or preloaded filters. Five fibrous filters with various particle collection efficiencies were studied: classes G4, M5, M6, F7, and combined F7 according to European standard EN779:2012. Filters were clogged with micronized rice particles containing the fungus Penicillium chrysogenum and then incubated for three weeks at 25°C and 90% relative humidity. The results indicated that the five clogged tested filters had various fungal growth capacities depending on their water retention capacity. Preloaded filters were subjected to a simulated ventilation restart in a controlled filtration device to quantify that the fraction of particles released was around 1% for the G4, 0.1% for the M5 and the M6, and 0.001% for the F7 and the combined F7 filter. The results indicate that the likelihood of fungal particle release by low efficiency filters is significantly higher than by high efficiency filters. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Personal continuous air monitor

DOEpatents

Morgan, Ronald G.; Salazar, Samuel A.

2000-01-01

A personal continuous air monitor capable of giving immediate warning of the presence of radioactivity has a filter/detector head to be worn in the breathing zone of a user, containing a filter mounted adjacent to radiation detectors, and a preamplifier. The filter/detector head is connected to a belt pack to be worn at the waist or on the back of a user. The belt pack contains a signal processor, batteries, a multichannel analyzer, a logic circuit, and an alarm. An air pump also is provided in the belt pack for pulling air through the filter/detector head by way of an air tube.

Aerosol distribution apparatus

DOEpatents

Hanson, W.D.

An apparatus for uniformly distributing an aerosol to a plurality of filters mounted in a plenum, wherein the aerosol and air are forced through a manifold system by means of a jet pump and released into the plenum through orifices in the manifold. The apparatus allows for the simultaneous aerosol-testing of all the filters in the plenum.

40 CFR 63.11567 - Who implements and enforces this subpart?

Code of Federal Regulations, 2010 CFR

2010-07-01

... Processing and Asphalt Roofing Manufacturing Other Requirements and Information § 63.11567 Who implements and...). 2. A high-efficiency air filter or fiber bed filter a. Inlet gas temperature b, andb. Pressure drop... the inlet gas temperature and pressure drop, you can use a leak detection system that identifies when...

ENVIRONMENTAL TECHNOLOGY VERIFICATON: TEST REPORT OF CONTROL OF BIOAEROSOLS IN HVAC SYSTEMS AAF INTERNATIONAL DRIPAK 90/95%

EPA Science Inventory

The Environmental Technology Verification report discusses the technology and performance of the DriPak 90/95% air filter for dust and bioaerosol filtration manufactured by AAF International. The pressure drop across the filter was 104 Pa clean and 348 Pa dust loaded, and the fil...

ENVIRONMENTAL TECHNOLOGY VERIFICATIONTEST REPORT OF CONTROL OF BIOAEROSOLS IN HVAC SYSTEMS AAF INTERNATIONAL BIOCEL I (TYPE SH)

EPA Science Inventory

The Environmental Technology Verification report discusses the technology and performance of the BioCel I (Type SH) air filter for dust and bioaerosol filtration manufactured by AAF International. The pressure drop across the filter was 236 Pa clean and 478 Pa dust loaded, and th...

ENVIRONMENTAL TECHNOLOGY VERIFICATION, TEST REPORT OF CONTROL OF BIOAEROSOLS IN HVAC SYSTEMS:AAF INTERNATIONAL, PERFECTPLEAT ULTRA, 175-102-863

EPA Science Inventory

The Environmental Technology Verification report discusses the technology and performance of the PerfectPleat Ultra 175-102-863 air filter for dust and bioaerosol filtration manufactured by AAF International. The pressure drop across the filter was 112 Pa clean and 229 Pa dust lo...

ENVIRONMENTAL TECHNOLOGY VERIFICATION, TEST REPORT OF CONTROL OF BIOAEROSOLS IN HVAC SYSTEMS, COLUMBUS INDUSTRIES SL-3 RING PANEL

EPA Science Inventory

The Environmental Technology Verification report discusses the technology and performance of the High Efficiency Mini Pleat air filter for dust and bioaerosol filtration manufactured by Columbus Industries. The pressure drop across the filter was 142 Pa clean and 283 Pa dust load...

Receptacle for Optical-Fiber Scraps

NASA Technical Reports Server (NTRS)

Nevin, R.

1986-01-01

Small pieces of glass trapped by moving air. Device traps fibers in section of black air-conditioner filter material. Filter section rests on metal screen above axial fan, which pulls air down through filter. Fan is small, quiet unit of type ordinarily used to cool electronic equipment.

Fibrous Filter to Protect Building Environments from Polluting Agents: A Review

NASA Astrophysics Data System (ADS)

Chavhan, Md. Vaseem; Mukhopadhyay, Arunangshu

2016-04-01

This paper discusses the use of fibrous filter to protect the building environments from air born polluting agents and especially of concern chemical, biological and radiological agents. Air-filtration includes removal of particulate from air and toxic gases from air. In air filtration, particulate which are mostly biological and radioactive types of agents can be removed by using mechanical and electrostatic filters. Some biological agents, which cannot be removed by air filtration alone, special techniques like antimicrobial finish, UV germicides, coated filters etc. are required. Biocide agent can be added into the fibre itself by grafting reaction to impart antimicrobial activity. Chemical agents like toxic gases can be removed by integrating adsorbents and sorbents in filters or by fibre modifications. It is also possible to impart catalytic conversion properties into the fibre to remove volatile gasous. Radioactive agents can be removed by particulate filter if present in the form of aerosol or by gas cleaning by the use of specific fibre impregnate.

40 CFR 60.273 - Emission monitoring.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) Inspecting the baghouse for air leaks, torn or broken bags or filter media, or any other condition that may....273 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... installs and continuously operates a bag leak detection system according to paragraph (e) of this section...

40 CFR 60.273 - Emission monitoring.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) Inspecting the baghouse for air leaks, torn or broken bags or filter media, or any other condition that may....273 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... installs and continuously operates a bag leak detection system according to paragraph (e) of this section...

40 CFR 60.273 - Emission monitoring.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) Inspecting the baghouse for air leaks, torn or broken bags or filter media, or any other condition that may....273 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED... installs and continuously operates a bag leak detection system according to paragraph (e) of this section...

Carbon Dioxide Flush of an Integrated Minimized Perfusion Circuit Prior to Priming Prevents Spontaneous Air Release Into the Arterial Line During Clinical Use.

PubMed

Stehouwer, Marco C; de Vroege, Roel; Hoohenkerk, Gerard J F; Hofman, Frederik N; Kelder, Johannes C; Buchner, Bas; de Mol, Bastian A; Bruins, Peter

2017-11-01

Recently, an oxygenator with an integrated centrifugal blood pump (IP) was designed to minimize priming volume and to reduce blood foreign surface contact even further. The use of this oxygenator with or without integrated arterial filter was compared with a conventional oxygenator and nonintegrated centrifugal pump. To compare the air removal characteristics 60 patients undergoing coronary artery bypass grafting were alternately assigned into one of three groups to be perfused with a minimized extracorporeal circuit either with the conventional oxygenator, the oxygenator with IP, or the oxygenator with IP plus integrated arterial filter (IAF). Air entering and leaving the three devices was measured accurately with a bubble counter during cardiopulmonary bypass. No significant differences between all groups were detected, considering air entering the devices. Our major finding was that in both integrated devices groups incidental spontaneous release of air into the arterial line in approximately 40% of the patients was observed. Here, detectable bolus air (>500 µm) was shown in the arterial line, whereas in the minimal extracorporeal circulation circuit (MECC) group this phenomenon was not present. We decided to conduct an amendment of the initial design with METC-approval. Ten patients were assigned to be perfused with an oxygenator with IP and IAF. Importantly, the integrated perfusion systems used in these patients were flushed with carbon dioxide (CO 2 ) prior to priming of the systems. In the group with CO 2 flush no spontaneous air release was observed in all cases and this was significantly different from the initial study with the group with the integrated device and IAF. This suggests that air spilling may be caused by residual air in the integrated device. In conclusion, integration of a blood pump may cause spontaneous release of large air bubbles (>500 µm) into the arterial line, despite the presence of an integrated arterial filter. CO 2 flushing of an integrated cardiopulmonary bypass system prior to priming may prevent spontaneous air release and is strongly recommended to secure patient safety. © 2017 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

JSF/F-35 Pollution Prevention Activities

DTIC Science & Technology

2006-05-01

Liquid Oxygen •Produces Oxygen-Rich Breathing Gas From Engine Bleed Air Using Molecular Sieve Technology •No Exotic Cleaning Solutions •Military No...Explosion from Bullets/Shrapnel •On-Board Inert Gas Generating System (OBIGGS) Replaced Halon 1301 •Filters out Oxygen from Ambient Air to Create...Supply System •Supply System Must Be Perfectly Clean •Best Cleaning Solutions Freon CFC-113 and HCFC-141b •On-Board Oxygen Generating System Replaced

HEPA air filter (image)

MedlinePlus

... pet dander and other irritating allergens from the air. Along with other methods to reduce allergens, such ... controlling the amount of allergens circulating in the air. HEPA filters can be found in most air ...

Methodology for modeling the microbial contamination of air filters.

PubMed

Joe, Yun Haeng; Yoon, Ki Young; Hwang, Jungho

2014-01-01

In this paper, we propose a theoretical model to simulate microbial growth on contaminated air filters and entrainment of bioaerosols from the filters to an indoor environment. Air filter filtration and antimicrobial efficiencies, and effects of dust particles on these efficiencies, were evaluated. The number of bioaerosols downstream of the filter could be characterized according to three phases: initial, transitional, and stationary. In the initial phase, the number was determined by filtration efficiency, the concentration of dust particles entering the filter, and the flow rate. During the transitional phase, the number of bioaerosols gradually increased up to the stationary phase, at which point no further increase was observed. The antimicrobial efficiency and flow rate were the dominant parameters affecting the number of bioaerosols downstream of the filter in the transitional and stationary phase, respectively. It was found that the nutrient fraction of dust particles entering the filter caused a significant change in the number of bioaerosols in both the transitional and stationary phases. The proposed model would be a solution for predicting the air filter life cycle in terms of microbiological activity by simulating the microbial contamination of the filter.

Integrating biofiltration with SVE: A case study

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

Lesley, M.P.; Rangan, C.R.

1996-12-01

A prototype integrated soil vacuum extraction/biofiltration system has been designed and installed at a gasoline contaminated LUST site in southern Delaware. The prototype system remediates contaminated moisture entrained in the air stream, employs automatic water level controls in the filters, and achieves maximum vapor extraction and VOC destruction efficiency with an optimum power input. In addition, the valving and piping layout allows the direction of air flow through the filters to be reversed at a given time interval, which minimizes biofouling, thereby increasing efficiency by minimizing the need for frequent cleaning. This integrated system achieves constant VOC destruction rates ofmore » 40 to 70% while maintaining optimal VOC removal rates from the subsurface. The modular design allows for easy mobilization, setup and demobilization at state-lead LUST sites throughout Delaware.« less

Detection of Legionella-contaminated aerosols in the vicinity of a bio-trickling filter of a breeding sow facility - A pilot study.

PubMed

Walser, Sandra M; Brenner, Bernhard; Wunderlich, Anika; Tuschak, Christian; Huber, Stefanie; Kolb, Stefanie; Niessner, Reinhard; Seidel, Michael; Höller, Christiane; Herr, Caroline E W

2017-01-01

The urbanization of agricultural areas results in a reduction of distances between residential buildings and livestock farms. In the public debate, livestock farming is increasingly criticized due to environmental disturbance and odor nuisance originating from such facilities. One method to reduce odor and ammonia is by exhaust air treatment, for example, by biological exhaust air purification processes with bio-trickling filters filled with tap water. Higher temperatures in the summer time and the generation of biofilms are ideal growth conditions for Legionella. However, there are no studies on the presence of Legionella in the water of bio-trickling filters and the release of Legionella-containing aerosols. Therefore, the aim of this study was to investigate Legionella in wash water and emitted bioaerosols of a bio-trickling filter system of a breeding sow facility. For this purpose, measurements were carried out using a cyclone sampler. In addition, samples of wash water were taken. Legionella were not found by culture methods. However, using molecular biological methods, Legionella spp. could be detected in wash water as well as in bioaerosol samples. With antibody-based methods, Legionella pneumophila were identified. Further studies are needed to investigate the environmental health relevance of Legionella-containing aerosols emitted by such exhaust air purification systems. Copyright © 2016 Elsevier B.V. All rights reserved.

Air-drying of cells, the novel conditions for stimulated synthesis of triacylglycerol in a Green Alga, Chlorella kessleri.

PubMed

Shiratake, Takuma; Sato, Atsushi; Minoda, Ayumi; Tsuzuki, Mikio; Sato, Norihiro

2013-01-01

Triacylglycerol is used for the production of commodities including food oils and biodiesel fuel. Microalgae can accumulate triacylglycerol under adverse environmental conditions such as nitrogen-starvation. This study explored the possibility of air-drying of green algal cells as a novel and simple protocol for enhancement of their triacylglycerol content. Chlorella kessleri cells were fixed on the surface of a glass fibre filter and then subjected to air-drying with light illumination. The dry cell weight, on a filter, increased by 2.7-fold in 96 h, the corresponding chlorophyll content ranging from 1.0 to 1.3-fold the initial one. Concomitantly, the triacylglycerol content remarkably increased to 70.3 mole% of fatty acids and 15.9% (w/w), relative to total fatty acids and dry cell weight, respectively, like in cells starved of nitrogen. Reduction of the stress of air-drying by placing the glass filter on a filter paper soaked in H2O lowered the fatty acid content of triacylglycerol to 26.4 mole% as to total fatty acids. Moreover, replacement of the H2O with culture medium further decreased the fatty acid content of triacylglycerol to 12.2 mole%. It thus seemed that severe dehydration is required for full induction of triacylglycerol synthesis, and that nutritional depletion as well as dehydration are crucial environmental factors. Meanwhile, air-drying of Chlamydomonas reinhardtii cells increased the triacylglycerol content to only 37.9 mole% of fatty acids and 4.8% (w/w), relative to total fatty acids and dry cell weight, respectively, and a marked decrease in the chlorophyll content, on a filter, of 33%. Air-drying thus has an impact on triacylglycerol synthesis in C. reinhardtii also, however, the effect is considerably limited, owing probably to instability of the photosynthetic machinery. This air-drying protocol could be useful for the development of a system for industrial production of triacylglycerol with appropriate selection of the algal species.

29 CFR 1910.134 - Respiratory protection.

Code of Federal Regulations, 2012 CFR

2012-07-01

... impact and penetration. High efficiency particulate air (HEPA) filter means a filter that is at least 99... as a high efficiency particulate air (HEPA) filter, or an air-purifying respirator equipped with a... frequency of respirator use (including use for rescue and escape); (C) The expected physical work effort; (D...

29 CFR 1910.134 - Respiratory protection.

Code of Federal Regulations, 2014 CFR

2014-07-01

... impact and penetration. High efficiency particulate air (HEPA) filter means a filter that is at least 99... as a high efficiency particulate air (HEPA) filter, or an air-purifying respirator equipped with a... frequency of respirator use (including use for rescue and escape); (C) The expected physical work effort; (D...

29 CFR 1910.134 - Respiratory protection.

Code of Federal Regulations, 2013 CFR

2013-07-01

... impact and penetration. High efficiency particulate air (HEPA) filter means a filter that is at least 99... as a high efficiency particulate air (HEPA) filter, or an air-purifying respirator equipped with a... frequency of respirator use (including use for rescue and escape); (C) The expected physical work effort; (D...

Effect of Intake Air Filter Condition on Light-Duty Gasoline Vehicles

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

Thomas, John F; Huff, Shean P; West, Brian H

2012-01-01

Proper maintenance can help vehicles perform as designed, positively affecting fuel economy, emissions, and the overall drivability. This effort investigates the effect of one maintenance factor, intake air filter replacement, with primary focus on vehicle fuel economy, but also examining emissions and performance. Older studies, dealing with carbureted gasoline vehicles, have indicated that replacing a clogged or dirty air filter can improve vehicle fuel economy and conversely that a dirty air filter can be significantly detrimental to fuel economy. The effect of clogged air filters on the fuel economy, acceleration and emissions of five gasoline fueled vehicles is examined. Fourmore » of these were modern vehicles, featuring closed-loop control and ranging in model year from 2003 to 2007. Three vehicles were powered by naturally aspirated, port fuel injection (PFI) engines of differing size and cylinder configuration: an inline 4, a V6 and a V8. A turbocharged inline 4-cylinder gasoline direct injection (GDI) engine powered vehicle was the fourth modern gasoline vehicle tested. A vintage 1972 vehicle equipped with a carburetor (open-loop control) was also examined. Results reveal insignificant fuel economy and emissions sensitivity of modern vehicles to air filter condition, but measureable effects on the 1972 vehicle. All vehicles experienced a measured acceleration performance penalty with clogged intake air filters.« less

Spectral Cloud-Filtering of AIRS Data: Non-Polar Ocean

NASA Technical Reports Server (NTRS)

Aumann, Hartmut H.; Gregorich, David; Barron, Diana

2004-01-01

The Atmospheric Infrared Sounder (AIRS) is a grating array spectrometer which covers the thermal infrared spectral range between 640 and 1700/cm. In order to retain the maximum radiometric accuracy of the AIRS data, the effects of cloud contamination have to be minimized. We discuss cloud filtering which uses the high spectral resolution of AIRS to identify about 100,000 of 500,000 non-polar ocean spectra per day as relatively "cloud-free". Based on the comparison of surface channels with the NCEP provided global real time sst (rtg.sst), AIRS surface sensitive channels have a cold bias ranging from O.5K during the day to 0.8K during the night. Day and night spatial coherence tests show that the cold bias is due to cloud contamination. During the day the cloud contamination is due to a 2-3% broken cloud cover at the 1-2 km altitude, characteristic of low stratus clouds. The cloud-contamination effects surface sensitive channels only. Cloud contamination can be reduced to 0.2K by combining the spectral filter with a spatial coherence threshold, but the yield drops to 16,000 spectra per day. AIRS was launched in May 2002 on the Earth Observing System (EOS) Aqua satellite. Since September 2002 it has returned 4 million spectra of the globe each day.

COMPUTATIONS ON THE PERFORMANCE OF PARTICLE FILTERS AND ELECTRONIC AIR CLEANERS

EPA Science Inventory

The paper discusses computations on the performance of particle filters and electronic air cleaners (EACs). The collection efficiency of particle filters and ACs is calculable if certain factors can be assumed or calibrated. For fibrous particulate filters, measurement of colle...

AMBIENT CARBON MONOXIDE MONITOR

EPA Science Inventory

A portable instrument has been designed and two units have been built to monitor the concentration of CO in ambient air. The air flows through a sampling section that is approximately 43 cm long with a 28-pass optical system that produces a total path of 12 meters. Gas-filter cor...

Active Control of Wind Tunnel Noise

NASA Technical Reports Server (NTRS)

Hollis, Patrick (Principal Investigator)

1991-01-01

The need for an adaptive active control system was realized, since a wind tunnel is subjected to variations in air velocity, temperature, air turbulence, and some other factors such as nonlinearity. Among many adaptive algorithms, the Least Mean Squares (LMS) algorithm, which is the simplest one, has been used in an Active Noise Control (ANC) system by some researchers. However, Eriksson's results, Eriksson (1985), showed instability in the ANC system with an ER filter for random noise input. The Restricted Least Squares (RLS) algorithm, although computationally more complex than the LMS algorithm, has better convergence and stability properties. The ANC system in the present work was simulated by using an FIR filter with an RLS algorithm for different inputs and for a number of plant models. Simulation results for the ANC system with acoustic feedback showed better robustness when used with the RLS algorithm than with the LMS algorithm for all types of inputs. Overall attenuation in the frequency domain was better in the case of the RLS adaptive algorithm. Simulation results with a more realistic plant model and an RLS adaptive algorithm showed a slower convergence rate than the case with an acoustic plant as a delay plant. However, the attenuation properties were satisfactory for the simulated system with the modified plant. The effect of filter length on the rate of convergence and attenuation was studied. It was found that the rate of convergence decreases with increase in filter length, whereas the attenuation increases with increase in filter length. The final design of the ANC system was simulated and found to have a reasonable convergence rate and good attenuation properties for an input containing discrete frequencies and random noise.

Chemical Protection Testing of Sorbent-Based Air Purification Components (APCs)

DTIC Science & Technology

2016-06-24

APC’s ability to filter air in a chemically contaminated environment. 15. SUBJECT TERMS Air purification component; APC; filtration fabric...FF, filter media, collective protection; individual protection. 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT SAR 18...incoming air. The intent of this process is to produce traceable, quantifiable, and defensible data that can be used to analyze an APC’s ability to filter

A problem of hospital hygiene: the presence of aspergilli in hospital wards with different air-conditioning features.

PubMed

Perdelli, Fernanda; Sartini, Marina; Spagnolo, Anna Maria; Dallera, Maurizio; Lombardi, Roberto; Cristina, Maria Luisa

2006-06-01

A total of 1,030 microbiological samples were taken in 3 hospital wards with different air-conditioning features: no conditioning system (ward A), a conditioning system equipped with minimum efficiency reporting value (MERV) filters (ward B), and a conditioning system thoroughly maintained and equipped with high-efficiency particulate air (HEPA) filters (absolute) (ward C). The air in each ward was sampled, and the bacterial and fungal concentrations were determined by active and passive methods. The concentration of fungi on surfaces was also determined. Active sampling showed positive samples in wards A and B only, with average values of 0.50 colony-forming units (CFU)/m(3) (95% CI, 0.30 to 0.70) in A and 0.16 CFU/m(3) (95% CI, 0.13 to 0.20) in B. Passive sampling was positive only in ward A (mean, 0.14 CFU/cm(2)/h; 95% CI, 0.13 to 0.15). Aspergillus was found in 27% and 22% of sampled surfaces in wards A and B, respectively, but in no samples from ward C. The most commonly found species was A. fumigatus (76% of cases in A and 34% of cases in B). The results show that the use of air-conditioning systems markedly reduces the concentration of aspergilli in the environment. Proper maintenance of these systems is clearly fundamental if their efficacy is to be ensured.

A new approach to assess occupational exposure to airborne fungal contamination and mycotoxins of forklift drivers in waste sorting facilities.

PubMed

Viegas, Carla; Faria, Tiago; de Oliveira, Ana Cebola; Caetano, Liliana Aranha; Carolino, Elisabete; Quintal-Gomes, Anita; Twarużek, Magdalena; Kosicki, Robert; Soszczyńska, Ewelina; Viegas, Susana

2017-11-01

The waste management industry is an important employer, and exposure of waste-handling workers to microorganisms is considered an occupational health problem. Besides fungal contamination, it is important to consider the co-occurrence of mycotoxins in this setting. Forklifts with closed cabinet and air conditioner are commonly used in waste industry to transport waste and other products within the facilities, possibly increasing the risk of exposure under certain conditions. The aim of this study was to assess the fungal contamination and mycotoxin levels in filters from the air conditioning system of forklift cabinets, as an indicator to assess occupational exposure of the drivers working in a waste sorting facility. Cytotoxicity was also assessed to understand and characterize the toxicity of the complex mixtures as present in the forklift filters. Aqueous extracts of filters from 11 vehicles were streaked onto 2% malt extract agar (MEA) with chloramphenicol (0.05 g/L) media, and in dichloran glycerol (DG18) agar-based media for morphological identification of the mycobiota. Real-time quantitative PCR amplification of genes from Aspergillus sections Fumigati, Flavi, Circumdati, and Versicolores was also performed. Mycotoxins were analyzed using LC-MS/MS system. Cytotoxicity of filter extracts was analyzed by using a MTT cell culture test. Aspergillus species were found most frequently, namely Aspergillus sections Circumdati (MEA 48%; DG18 41%) and Nigri (MEA 32%; DG18 17.3%). By qPCR, only Aspergillus section Fumigati species were found, but positive results were obtained for all assessed filters. No mycotoxins were detected in aqueous filter extracts, but most extracts were highly cytotoxic (n = 6) or medium cytotoxic (n = 4). Although filter service life and cytotoxicity were not clearly correlated, the results suggest that observing air conditioner filter replacement frequency may be a critical aspect to avoid worker's exposure. Further research is required to check if the environmental conditions as present in the filters could allow the production of mycotoxins and their dissemination in the cabinet during the normal use of the vehicles.

Activated charcoal filters: Water treatment, pollution control, and industrial applications. (Latest citations from the Patent Bibliographic database with exemplary claims. ) Published Search

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

Not Available

The bibliography contains citations of selected patents concerning activated charcoal filters and their applications in water treatment, pollution control, and industrial processes. Filtering methods and equipment for air and water purification, industrial distillation and extraction, industrial leaching, and filtration of toxic materials and contaminants are described. Applications include drinking water purification, filtering beverages, production of polymer materials, solvent and metal recovery, waste conversion, automotive fuel and exhaust systems, swimming pool filtration, tobacco smoke filters, kitchen ventilators, medical filtration treatment, and odor absorbing materials. (Contains 250 citations and includes a subject term index and title list.)

Investigations into the application of a combination of bioventing and biotrickling filter technologies for soil decontamination processes--a transition regime between bioventing and soil vapour extraction.

PubMed

Magalhães, S M C; Ferreira Jorge, R M; Castro, P M L

2009-10-30

Bioventing has emerged as one of the most cost-effective in situ technologies available to address petroleum light-hydrocarbon spills, one of the most common sources of soil pollution. However, the major drawback associated with this technology is the extended treatment time often required. The present study aimed to illustrate how an intended air-injection bioventing technology can be transformed into a soil vapour extraction effort when the air flow rates are pushed to a stripping mode, thus leading to the treatment of the off-gas resulting from volatilisation. As such, a combination of an air-injection bioventing system and a biotrickling filter was applied for the treatment of contaminated soil, the latter aiming at the treatment of the emissions resulting from the bioventing process. With a moisture content of 10%, soil contaminated with toluene at two different concentrations, namely 2 and 14 mg g soil(-1), were treated successfully using an air-injection bioventing system at a constant air flow rate of ca. 0.13 dm(3) min(-1), which led to the removal of ca. 99% toluene, after a period of ca. 5 days of treatment. A biotrickling filter was simultaneously used to treat the outlet gas emissions, which presented average removal efficiencies of ca. 86%. The proposed combination of biotechnologies proved to be an efficient solution for the decontamination process, when an excessive air flow rate was applied, reducing both the soil contamination and the outlet gas emissions, whilst being able to reduce the treatment time required by bioventing only.

ENVIRONMENTAL TECHNOLOGY VERIFICATION: TEST REPORT OF CONTROL OF BIOAEROSOLS IN HLVAC SYSTEMS: AEOLUS CORPORATION SYNTHETIC MINIPLEAT V-CELL, SMV-M13-2424

EPA Science Inventory

The Environmental Technology Verification report discusses the technology and performance of the Synthetic Minipleat V-Cell, SMV-M13-2424 air filter for dust and bioaerosol filtration manufactured by Aeolus Corporation. The pressure drop across the filter was 77 Pa clean and 348 ...

ENVIRONMENTAL TECHNOLOGY VERIFICATION: TEST REPORT OF CONTROL OF BIOAEROSOLS IN HVAC SYSTEMS: AEOLUS CORPORATION SYNTHETIC MINIPLEAT V-CELL, SMV-M14-2424

EPA Science Inventory

The Environmental Technology Verification report discusses the technology and performance of the Synthetic Minipleat V-Cell, SMV-M14-2424 air filter for dust and bioaerosol filtration manufactured by Aeolus Corporation. The pressure drop across the filter was 104 Pa clean and 348...

ETV TEST REPORT OF CONTROL OF BIOAEROSOLS IN HVAC SYSTEMS GLASFLOSS INDUSTRIES Z-PAK SERIES S, MODEL ZPS24241295BO

EPA Science Inventory

The Environmental Technology Verification report discusses the technology and performance of the Z-Pak Series S, Model ZPS24241295B0 air filter for dust and bioaerosol filtration manufactured by Glasfloss Industries, Inc. The pressure drop across the filter was 91 Pa clean and 34...

Assessment of polycarbonate filter in a molecular analytical system for the microbiological quality monitoring of recycled waters onboard ISS.

PubMed

Bechy-Loizeau, Anne-Laure; Flandrois, Jean-Pierre; Abaibou, Hafid

2015-07-01

On the ISS, as on Earth, water is an essential element for life and its quality control on a regular basis allows to ensure the health of the crew and the integrity of equipment. Currently, microbial water analysis onboard ISS still relies on the traditional culture-based microbiology methods. Molecular methods based on the amplification of nucleic acids for microbiological analysis of water quality show enormous potential and are considered as the best alternative to culture-based methods. For this reason, the Midass, a fully integrated and automated prototype was designed conjointly by ESA and bioMérieux for a rapid monitoring of the microbiological quality of air. The prototype allows air sampling, sample processing and the amplification/detection of nucleic acids. We describe herein the proof of principle of an analytical approach based on molecular biology that could fulfill the ESA's need for a rapid monitoring of the microbiological quality of recycled water onboard ISS. Both concentration and recovery of microorganisms are the main critical steps when the microfiltration technology is used for water analysis. Among filters recommended standards for monitoring the microbiological quality of the water, the polycarbonate filter was fully in line with the requirements of the ISO 7704-1985 standard in terms of efficacy of capture and recovery of bacteria. Moreover, this filter does not retain nucleic acids on the surface and has no inhibitory effect on their downstream processing steps such as purification and amplification/detection. Although the Midass system was designed for the treatment of air samples, the first results on the integration of PC filters were encouraging. Nevertheless, system modifications are needed to better adapt the Midass system for the monitoring of the microbiological water quality. Copyright © 2015 The Committee on Space Research (COSPAR). Published by Elsevier Ltd. All rights reserved.

A dense cell retention culture system using stirred ceramic membrane reactor.

PubMed

Suzuki, T; Sato, T; Kominami, M

1994-11-20

A novel reactor design incorporating porous ceramic tubes into a stirred jar fermentor was developed. The stirred ceramic membrane reactor has two ceramic tubular membrane units inside the vessel and maintains high filtration flux by alternating use for filtering and recovering from clogging. Each filter unit was linked for both extraction of culture broth and gas sparging. High permeability was maintained for long periods by applying the periodical control between filtering and air sparging during the stirred retention culture of Saccharomyces cerevisiae. The ceramic filter aeration system increased the k(L)a to about five times that of ordinary gas sparing. Using the automatic feeding and filtering system, cell mass concentration reached 207 g/L in a short time, while it was 64 g/L in a fed-batch culture. More than 99% of the growing cells were retained in the fermentor by the filtering culture. Both yield and productivity of cells were also increased by controlling the feeding of fresh medium and filtering the supernatant of the dense cells culture. (c) 1994 John Wiley & Sons, Inc.

Particulate generation and control in the PREPP (Process Experimental Pilot Plant) incinerator

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

Stermer, D.L.; Gale, L.G.

1989-03-01

Particulate emissions in radioactive incineration systems using a wet scrubbing system are generally ultimately controlled by flowing the process offgas stream through a high-efficiency filter, such as a High Efficient Particulate Air (HEPA) filter. Because HEPA filters are capable of reducing particulate emissions over an order of magnitude below regulatory limits, they consequently are vulnerable to high loading rates. This becomes a serious handicap in radioactive systems when filter change-out is required at an unacceptably high rate. The Process Experimental Pilot Plant (PREPP) incineration system is designed for processing retrieved low level mixed hazardous waste. It has a wet offgasmore » treatment system consisting of a Quencher, Venturi Scrubber, Entrainment Eliminator, Mist Eliminator, two stages of HEPA filters, and induced draft fans. During previous tests, it was noted that the offgas filters loaded with particulate at a rate requiring replacement as often as every four hours. During 1988, PREPP conducted a series of tests which included an investigation of the causes of heavy particulate accumulation on the offgas filters in relation to various operating parameters. This was done by measuring the particulate concentrations in the offgas system, primarily as a function of scrub solution salt concentration, waste feed rate, and offgas flow rate. 2 figs., 9 tabs.« less

Comparison of nonwoven fiberglass and stainless steel microfiber media in aerosol coalescence filtration

NASA Astrophysics Data System (ADS)

Manzo, Gabriel

Coalescing filters are used to remove small liquid droplets from air streams. They have numerous industrial applications including dehumidification, cabin air filtration, compressed air filtration, metal working, CCV, and agriculture. In compressed air systems, oils used for lubrication of compressor parts can aerosolize into the main air stream causing potential contamination concerns for downstream applications. In many systems, humid air can present problems to sensitive equipment and sensors. As the humid air cools, small water drops condense and can disrupt components that need to be kept dry. Fibrous nonwoven filter media are commonly used to coalesce small drops into larger drops for easier removal. The coalescing performance of a medium is dependent upon several parameters including permeability, porosity, and wettability. In many coalescing filters, glass fibers are used. In this work, the properties of steel fiber media are measured to see how these properties compare to glass fiber media. Steel fiber media has different permeability, porosity and wettability to oil and water than fiber glass media. These differences can impact coalescence performance. The impact of these differences in properties on coalescence filtration performance was evaluated in a coalescence test apparatus. The overall coalescence performance of the steel and glass nonwoven fiber media are compared using a filtration efficiency and filtration index. In many cases, the stainless steel media performed comparably to fiber glass media with efficiencies near 90%. Since stainless steel media had lower pressure drops than fiber glass media, its filtration index values were significantly higher. Broader impact of this work is the use of stainless steel fiber media as an alternative to fiber glass media in applications where aerosol filtration is needed to protect the environment or sensitive equipment and sensors.

Modeling, Monitoring and Fault Diagnosis of Spacecraft Air Contaminants

NASA Technical Reports Server (NTRS)

Ramirez, W. Fred; Skliar, Mikhail; Narayan, Anand; Morgenthaler, George W.; Smith, Gerald J.

1996-01-01

Progress and results in the development of an integrated air quality modeling, monitoring, fault detection, and isolation system are presented. The focus was on development of distributed models of the air contaminants transport, the study of air quality monitoring techniques based on the model of transport process and on-line contaminant concentration measurements, and sensor placement. Different approaches to the modeling of spacecraft air contamination are discussed, and a three-dimensional distributed parameter air contaminant dispersion model applicable to both laminar and turbulent transport is proposed. A two-dimensional approximation of a full scale transport model is also proposed based on the spatial averaging of the three dimensional model over the least important space coordinate. A computer implementation of the transport model is considered and a detailed development of two- and three-dimensional models illustrated by contaminant transport simulation results is presented. The use of a well established Kalman filtering approach is suggested as a method for generating on-line contaminant concentration estimates based on both real time measurements and the model of contaminant transport process. It is shown that high computational requirements of the traditional Kalman filter can render difficult its real-time implementation for high-dimensional transport model and a novel implicit Kalman filtering algorithm is proposed which is shown to lead to an order of magnitude faster computer implementation in the case of air quality monitoring.

77 FR 60887 - Airworthiness Directives; Alpha Aviation Concept Limited Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-10-05

... possible installation of non-conforming air filter elements that are not fitted with metallic mesh and... finding a non conforming air filter fitted to an overseas aircraft during maintenance. Investigation revealed that air filters with P/N 57.34.00.010 supplied by CEAPR between June 2009 and April 2012 may not...

77 FR 44511 - Airworthiness Directives; Alpha Aviation Concept Limited Airplanes

Federal Register 2010, 2011, 2012, 2013, 2014

2012-07-30

... possible installation of non-conforming air filter elements that are not fitted with metallic mesh and... conforming air filter fitted to an overseas aircraft during maintenance. Investigation revealed that air filters with P/N 57.34.00.010 supplied by CEAPR between June 2009 and April 2012 may not have the metallic...

40 CFR 721.10411 - Alkanenitrile, bis(cyanoalkyl)amino (generic) (P-07-537).

Code of Federal Regulations, 2012 CFR

2012-07-01

... with N100 (if oil aerosols absent), R100, or P100 filters; NIOSH-certified powered air-purifying respirator equipped with a loose- fitting hood or helmet and high efficiency particulate air (HEPA) filters... HEPA filters; or NIOSH-certified supplied-air respirator operated in pressure demand or continuous flow...

40 CFR 721.10411 - Alkanenitrile, bis(cyanoalkyl)amino (generic) (P-07-537).

Code of Federal Regulations, 2013 CFR

2013-07-01

... with N100 (if oil aerosols absent), R100, or P100 filters; NIOSH-certified powered air-purifying respirator equipped with a loose- fitting hood or helmet and high efficiency particulate air (HEPA) filters... HEPA filters; or NIOSH-certified supplied-air respirator operated in pressure demand or continuous flow...

40 CFR 721.10411 - Alkanenitrile, bis(cyanoalkyl)amino (generic) (P-07-537).

Code of Federal Regulations, 2014 CFR

2014-07-01

... with N100 (if oil aerosols absent), R100, or P100 filters; NIOSH-certified powered air-purifying respirator equipped with a loose- fitting hood or helmet and high efficiency particulate air (HEPA) filters... HEPA filters; or NIOSH-certified supplied-air respirator operated in pressure demand or continuous flow...

TEST METHODS TO CHARACTERIZE PARTICULATE MATTER EMISSIONS AND DEPOSITION RATES IN A RESEARCH HOUSE

EPA Science Inventory

The paper discusses test methods to characterize particulate matter (PM) emissions and deposition rates in a research house. In a room in the research house, specially configured for PM source testing, a high-efficiency particulate air (HEPA)-filtered air supply system, used for...

Mold Occurring on the Air Cleaner High-Efficiency Particulate Air Filters Used in the Houses of Child Patients with Atopic Dermatitis

PubMed Central

Kim, Seong Hwan; Ahn, Geum Ran; Son, Seung Yeol; Bae, Gwi-Nam

2014-01-01

Fungi are the known sources of irritation associated with atopic diseases (e.g., asthma, allergic rhinoconjunctivitis, and atopic eczema). To quantitatively estimate their presence in the indoor environment of atopic dermatitis-inflicted child patient's houses (ADCPHs), the high-efficiency particulate air (HEPA) filters installed inside the air cleaners of three different ADCPHs were investigated for the presence of mold. The air cleaner HEPA filters obtained from the three different ADCPHs were coded as HEPA-A, -B, and -C, respectively, and tested for the presence of mold. The colony forming units (CFUs) corresponding to the HEPA-A, -B, and -C filters were estimated to be 6.51 × 102 ± 1.50 × 102 CFU/cm2, 8.72 × 102 ± 1.69 × 102 CFU/cm2, and 9.71 × 102 ± 1.35 × 102 CFU/cm2, respectively. Aspergillus, Penicillium, Alternaria, Cladosporium, Trichoderma, and other fungal groups were detected in the 2,494 isolates. The distribution of these fungal groups differed among the three filters. Cladosporium was the major fungal group in filters HEPA-A and -C, whereas Penicillium was the major fungal group in the filter HEPA-B. Nine fungal species, including some of the known allergenic species, were identified in these isolates. Cladosporium cladosporioides was the most common mold among all the three filters. This is the first report on the presence of fungi in the air cleaner HEPA filters from ADCPHs in Korea. PMID:25346608

Radon detection

DOEpatents

MacArthur, D.W.; Allander, K.S.; Bounds, J.A.

1994-01-25

A detector for atmospheric radon using a long range alpha detector as its sensing element is described. An electrostatic filter removes ions from ambient air, while allowing radon atoms to pass into a decay cavity. Here, radon atoms are allowed to decay, creating air ions. These air ions are drawn by a fan through a second electrostatic filter which can be activated or deactivated, and into the long range alpha detector. With the second electrostatic filter activated, no air ions are allowed to pass, and the signal output from the long range alpha detector consists of only the electronic background. With the second electrostatic filter deactivated, air ions and cosmic rays will be detected. The cosmic ray contribution can be minimized by shielding. 3 figures.

Radon detection

DOEpatents

MacArthur, Duncan W.; Allander, Krag S.; Bounds, John A.

1994-01-01

A detector for atmospheric radon using a long range alpha detector as its sensing element. An electrostatic filter removes ions from ambient air, while allowing radon atoms to pass into a decay cavity. Here, radon atoms are allowed to decay, creating air ions. These air ions are drawn by a fan through a second electrostatic filter which can be activated or deactivated, and into the long range alpha detector. With the second electrostatic filter activated, no air ions are allowed to pass, and the signal output from the long range alpha detector consists of only the electronic background. With the second electrostatic filter deactivated, air ions and cosmic rays will be detected. The cosmic ray contribution can be minimized by shielding.

Control of experimental uncertainties in filtered Rayleigh scattering measurements

NASA Technical Reports Server (NTRS)

Forkey, Joseph N.; Finkelstein, N. D.; Lempert, Walter R.; Miles, Richard B.

1995-01-01

Filtered Rayleigh Scattering is a technique which allows for measurement of velocity, temperature, and pressure in unseeded flows, spatially resolved in 2-dimensions. We present an overview of the major components of a Filtered Rayleigh Scattering system. In particular, we develop and discuss a detailed theoretical model along with associated model parameters and related uncertainties. Based on this model, we then present experimental results for ambient room air and for a Mach 2 free jet, including spatially resolved measurements of velocity, temperature, and pressure.

Methodology for Modeling the Microbial Contamination of Air Filters

PubMed Central

Joe, Yun Haeng; Yoon, Ki Young; Hwang, Jungho

2014-01-01

In this paper, we propose a theoretical model to simulate microbial growth on contaminated air filters and entrainment of bioaerosols from the filters to an indoor environment. Air filter filtration and antimicrobial efficiencies, and effects of dust particles on these efficiencies, were evaluated. The number of bioaerosols downstream of the filter could be characterized according to three phases: initial, transitional, and stationary. In the initial phase, the number was determined by filtration efficiency, the concentration of dust particles entering the filter, and the flow rate. During the transitional phase, the number of bioaerosols gradually increased up to the stationary phase, at which point no further increase was observed. The antimicrobial efficiency and flow rate were the dominant parameters affecting the number of bioaerosols downstream of the filter in the transitional and stationary phase, respectively. It was found that the nutrient fraction of dust particles entering the filter caused a significant change in the number of bioaerosols in both the transitional and stationary phases. The proposed model would be a solution for predicting the air filter life cycle in terms of microbiological activity by simulating the microbial contamination of the filter. PMID:24523908

Activated-charcoal filters: water treatment, pollution control, and industrial applications. January 1970-July 1988 (citations from the US Patent data base). Report for January 1970-July 1988

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

Not Available

This bibliography contains citations of selected patents concerning activated-charcoal filters and their applications in water treatment, pollution control, and industrial processes. Filtering methods and equipment for air and water purification, industrial distillation and extraction, industrial leaching, and filtration of toxic gases and pollutants are described. Applications include drinking water purification, filtering beverages, production of polymer materials, solvent and metal recovery, swimming pool filtration, waste conversion, automobile fuel and exhaust systems, and footwear deodorizing. (Contains 129 citations fully indexed and including a title list.)

Communication System Simulation Workstation

DTIC Science & Technology

1990-01-30

SIMULATION WORKSTATION Grant # AFOSR-89-0117 Submitted to: DEPARTMENT OF AIR FORCE AIR FORCE OFFICE OF SCIENTIFIC RESEARCH BOLLING AIR FORCE BASE , DC...CORRESPONOENCiA. PAGUETES. CONIIUCE. r ACTUHA. Y CONOCIMIENTO DE EMBAROUES. THIS PURCHASE ORDER [,rccion Cablegralica .1,1 Addrv~s NO MUST APPEAR ON ALL...sub-band decomposition was developed, PKX, based on the modulation of a single prototype filter. This technicde was introduced first by Nassbauner and

The transfer of carbon fibers through a commercial aircraft water separator and air cleaner

NASA Technical Reports Server (NTRS)

Meyers, J. A.

1979-01-01

The fraction of carbon fibers passing through a water separator and an air filter was determined in order to estimate the proportion of fibers outside a closed aircraft that are transmitted to the electronics through the air conditioning system. When both devices were used together and only fibers 3 mm or larger were considered, a transfer function of .001 was obtained.

Comparing charcoal and zeolite reflection filters for volatile anaesthetics: A laboratory evaluation.

PubMed

Sturesson, Louise W; Frennström, Jan O; Ilardi, Marcella; Reinstrup, Peter

2015-08-01

A modified heat-moisture exchanger that incorporates a reflecting filter for use with partial rebreathing of exhaled volatile anaesthetics has been commercially available since the 1990 s. The main advantages of the device are efficient delivery of inhaled sedation to intensive care patients and reduced anaesthetic consumption during anaesthesia. However, elevated arterial CO2 values have been observed with an anaesthetic conserving device compared with a conventional heat and moisture exchanger, despite compensation for larger apparatus dead space. The objective of this study is to thoroughly explore the properties of two reflecting materials (charcoal and zeolites). A controlled, prospective, observational laboratory study. Lund University Hospital, Sweden, from December 2011 to December 2012. None. Three filters, with identical volumes, were compared using different volatile anaesthetics at different conditions of temperature and moisture. The filtering materials were charcoal or zeolite. Glass spheres were used as an inert control. Consumption of volatile anaesthetics using different reflecting materials in filters at different conditions regarding temperature and moisture. CO2 reflection by the filtering materials: glass spheres, charcoal or zeolite. Isoflurane consumption in an open system was 60.8 g h(-1). The isoflurane consumption in dry, warm air was 39.8 g h(-1) with glass spheres. Changing to charcoal and zeolite had a profound effect on isoflurane consumption, 11.8 and 10.7 g h(-1), respectively. Heating and humidifying the air as well as the addition of N2O created only minor changes in consumption. The percentage of isoflurane conserved by the charcoal filter was independent of the isoflurane concentration (0.5 to 4.5%). Reflection of sevoflurane, desflurane and halothane by the charcoal filter was similar to reflection of isoflurane. Both charcoal and zeolite filters had CO2 reflecting properties and end-tidal CO2 increased by 3 to 3.7% compared with glass spheres. This increase was attenuated to 1 to 1.4% when the air was heated and humidified, and isoflurane was added. Charcoal and zeolite possess gas-reflecting properties, which can be used to conserve volatile anaesthetics. They also reflect CO2. The degree of CO2 reflection was reduced by heating and humidifying the air.

Test Operations Procedure (TOP) 08-2-197 Chemical Protection Testing of Sorbent-Based Air Purification Components (APCs)

DTIC Science & Technology

2016-06-24

APC’s ability to filter air in a chemically contaminated environment. 15. SUBJECT TERMS Air purification component; APC; filtration fabric...FF, filter media, collective protection; individual protection. 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT SAR 18...incoming air. The intent of this process is to produce traceable, quantifiable, and defensible data that can be used to analyze an APC’s ability to filter

40 CFR 721.10077 - 3H-1,2,4-Triazol-3-one, 1,2-dihydro-.

Code of Federal Regulations, 2011 CFR

2011-07-01

...-fitting respirator equipped with N100 (if aerosols absent), R100, or P100 filters (either half- or full... Efficiency Particulate Air (HEPA) filters; powered air-purifying respirator equipped with a tight-fitting facepiece (either half- or full-face) and HEPA filters; and supplied-air respirator operated in pressure...

40 CFR 721.10077 - 3H-1,2,4-Triazol-3-one, 1,2-dihydro-.

Code of Federal Regulations, 2013 CFR

2013-07-01

...-fitting respirator equipped with N100 (if aerosols absent), R100, or P100 filters (either half- or full... Efficiency Particulate Air (HEPA) filters; powered air-purifying respirator equipped with a tight-fitting facepiece (either half- or full-face) and HEPA filters; and supplied-air respirator operated in pressure...

40 CFR 721.10077 - 3H-1,2,4-Triazol-3-one, 1,2-dihydro-.

Code of Federal Regulations, 2012 CFR

2012-07-01

...-fitting respirator equipped with N100 (if aerosols absent), R100, or P100 filters (either half- or full... Efficiency Particulate Air (HEPA) filters; powered air-purifying respirator equipped with a tight-fitting facepiece (either half- or full-face) and HEPA filters; and supplied-air respirator operated in pressure...

40 CFR 721.10077 - 3H-1,2,4-Triazol-3-one, 1,2-dihydro-.

Code of Federal Regulations, 2014 CFR

2014-07-01

...-fitting respirator equipped with N100 (if aerosols absent), R100, or P100 filters (either half- or full... Efficiency Particulate Air (HEPA) filters; powered air-purifying respirator equipped with a tight-fitting facepiece (either half- or full-face) and HEPA filters; and supplied-air respirator operated in pressure...

Fractional kalman filter to estimate the concentration of air pollution

NASA Astrophysics Data System (ADS)

Vita Oktaviana, Yessy; Apriliani, Erna; Khusnul Arif, Didik

2018-04-01

Air pollution problem gives important effect in quality environment and quality of human’s life. Air pollution can be caused by nature sources or human activities. Pollutant for example Ozone, a harmful gas formed by NOx and volatile organic compounds (VOCs) emitted from various sources. The air pollution problem can be modeled by TAPM-CTM (The Air Pollution Model with Chemical Transport Model). The model shows concentration of pollutant in the air. Therefore, it is important to estimate concentration of air pollutant. Estimation method can be used for forecast pollutant concentration in future and keep stability of air quality. In this research, an algorithm is developed, based on Fractional Kalman Filter to solve the model of air pollution’s problem. The model will be discretized first and then it will be estimated by the method. The result shows that estimation of Fractional Kalman Filter has better accuracy than estimation of Kalman Filter. The accuracy was tested by applying RMSE (Root Mean Square Error).

[The use of individual protective devices for decreasing the microbial contamination of the inhaled air].

PubMed

Sedov, A V; Akin'shin, A V; Tregub, T I

1995-01-01

The work was aimed to justify application of gas masks and respirators with autonomous air source fo lower bacterial contamination of inhaled air. The studies also covered possible catch of bacteria by cotton and filters FPP-15-1.5, those composed of antimicrobial materials, containing furagin or copper ions. As the studies proved, for lower bacterial contaminations of inhaled air one can apply autonomous air source apparatus with filters made of Petrianov tissue, antimicrobial tissue (containing furagin or copper ions), as they reduce fungal content of the air. Such filters are self-disinfecting, but do not influence total contamination of the air.

Apparatus for measuring the decontamination factor of a multiple filter air-cleaning system

DOEpatents

Ortiz, John P.

1986-01-01

An apparatus for measuring the overall decontamination factor of first and second filters located in a plenum. The first filter separates the plenum's upstream and intermediate chambers. The second filter separates the plenum's intermediate and downstream chambers. The apparatus comprises an aerosol generator that generates a challenge aerosol. An upstream collector collects unfiltered aerosol which is piped to first and second dilution stages and then to a laser aerosol spectrometer. An intermediate collector collects challenge aerosol that penetrates the first filter. The filtered aerosol is piped to the first dilution stage, diluted, and then piped to the laser aerosol spectrometer which detects single particles. A downstream collector collects challenge aerosol that penetrates both filters. The twice-filtered aerosol is piped to the aerosol spectrometer. A pump and several valves control the movement of aerosol within the apparatus.

Apparatus for measuring the decontamination factor of a multiple filter air-cleaning system

DOEpatents

Ortiz, J.P.

1985-07-03

An apparatus for measuring the overall decontamination factors of first and second filters located in a plenum. The first filter separates the plenum's upstream and intermediate chambers. The second filter separates the plenum's intermediate and downstream chambers. The apparatus comprises an aerosol generator that generates a challenge aerosol. An upstream collector collects unfiltered aerosol which is piped to first and second dilution stages and then to a laser aerosol spectrometer. An intermediate collector collects challenge aerosol that penetrates the first filter. The filtered aerosol is piped to the first dilution stage, diluted, and then piped to the laser aerosol spectrometer which detects single particles. A downstream collector collects challenge aerosol that penetrates both filters. The twice-filtered aerosol is piped to the aerosol spectrometer. A pump and several valves control the movement of aerosol within the apparatus.

“A System for Automatically Maintaining Pressure in a Commercial Truck Tire”

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

Maloney, John

2017-07-07

Under-inflated tires significantly reduce a vehicle’s fuel efficiency by increasing rolling resistance (drag force). The Air Maintenance Technology (“AMT”) system developed through this project replenishes lost air and maintains optimal tire cavity pressure whenever the tire is rolling in service, thus improving overall fuel economy by reducing the tire’s rolling resistance. The system consists of an inlet air filter, an air pump driven by tire deformation during rotation, and a pressure regulating device. Pressurized air in the tire cavity naturally escapes by diffusion through the tire and wheel, leaks in tire seating, and through the filler valve and its seating.more » As a result, tires require constant maintenance to replenish lost air. Since manual tire inflation maintenance is both labor intensive and time consuming, it is frequently overlooked or ignored. By automating the maintenance of optimal tire pressure, the tire’s contribution to the vehicle’s overall fuel economy can be maximized. The work was divided into three phases. The objectives of Phase 1, Planning and Initial Design, resulted in an effective project plan and to create a baseline design. The objectives for Phase 2, Design and Process Optimization, were: to identify finalized design for the pump, regulator and filter components; identify a process to build prototype tires; assemble prototype tires; test prototype tires and document results. The objectives of Phase 3, Design Release and Industrialization, were to finalize system tire assembly, perform release testing and industrialize the assembly process.« less

Air cleaning technologies: an evidence-based analysis.

PubMed

2005-01-01

This health technology policy assessment will answer the following questions: When should in-room air cleaners be used?How effective are in-room air cleaners?Are in-room air cleaners that use combined HEPA and UVGI air cleaning technology more effective than those that use HEPA filtration alone?What is the Plasmacluster ion air purifier in the pandemic influenza preparation plan?The experience of severe acute respiratory syndrome (SARS) locally, nationally, and internationally underscored the importance of administrative, environmental, and personal protective infection control measures in health care facilities. In the aftermath of the SARS crisis, there was a need for a clearer understanding of Ontario's capacity to manage suspected or confirmed cases of airborne infectious diseases. In so doing, the Walker Commission thought that more attention should be paid to the potential use of new technologies such as in-room air cleaning units. It recommended that the Medical Advisory Secretariat of the Ontario Ministry of Health and Long-Term Care evaluate the appropriate use and effectiveness of such new technologies. Accordingly, the Ontario Health Technology Advisory Committee asked the Medical Advisory Secretariat to review the literature on the effectiveness and utility of in-room air cleaners that use high-efficiency particle air (HEPA) filters and ultraviolet germicidal irradiation (UVGI) air cleaning technology. Additionally, the Ontario Health Technology Advisory Committee prioritized a request from the ministry's Emergency Management Unit to investigate the possible role of the Plasmacluster ion air purifier manufactured by Sharp Electronics Corporation, in the pandemic influenza preparation plan. Airborne transmission of infectious diseases depends in part on the concentration of breathable infectious pathogens (germs) in room air. Infection control is achieved by a combination of administrative, engineering, and personal protection methods. Engineering methods that are usually carried out by the building's heating, ventilation, and air conditioning (HVAC) system function to prevent the spread of airborne infectious pathogens by diluting (dilution ventilation) and removing (exhaust ventilation) contaminated air from a room, controlling the direction of airflow and the air flow patterns in a building. However, general wear and tear over time may compromise the HVAC system's effectiveness to maintain adequate indoor air quality. Likewise, economic issues may curtail the completion of necessary renovations to increase its effectiveness. Therefore, when exposure to airborne infectious pathogens is a risk, the use of an in-room air cleaner to reduce the concentration of airborne pathogens and prevent the spread of airborne infectious diseases has been proposed as an alternative to renovating a HVAC system. Airborne transmission is the spread of infectious pathogens over large distances through the air. Infectious pathogens, which may include fungi, bacteria, and viruses, vary in size and can be dispersed into the air in drops of moisture after coughing or sneezing. Small drops of moisture carrying infectious pathogens are called droplet nuclei. Droplet nuclei are about 1 to 5μm in diameter. This small size in part allows them to remain suspended in the air for several hours and be carried by air currents over considerable distances. Large drops of moisture carrying infectious pathogens are called droplets. Droplets being larger than droplet nuclei, travel shorter distances (about 1 metre) before rapidly falling out of the air to the ground. Because droplet nuclei remain airborne for longer periods than do droplets, they are more amenable to engineering infection control methods than are droplets. Droplet nuclei are responsible for the airborne transmission of infectious diseases such as tuberculosis, chicken pox (varicella), measles (rubeola), and dessiminated herpes zoster, whereas close contact is required for the direct transmission of infectious diseases transmitted by droplets, such as influenza (the flu) and SARS. In-room air cleaners are supplied as portable or fixed devices. Fixed devices can be attached to either a wall or ceiling and are preferred over portable units because they have a greater degree of reliability (if installed properly) for achieving adequate room air mixing and airflow patterns, which are important for optimal effectiveness. Through a method of air recirculation, an in-room air cleaner can be used to increase room ventilation rates and if used to exhaust air out of the room it can create a negative-pressure room for airborne infection isolation (AII) when the building's HVAC system cannot do so. A negative-pressure room is one where clean air flows into the room but contaminated air does not flow out of it. Contaminated room air is pulled into the in-room air cleaner and cleaned by passing through a series of filters, which remove the airborne infectious pathogens. The cleaned air is either recirculated into the room or exhausted outside the building. By filtering contaminated room air and then recirculating the cleaned air into the room, an in-room air cleaner can improve the room's ventilation. By exhausting the filtered air to the outside the unit can create a negative-pressure room. There are many types of in-room air cleaners. They vary widely in the airflow rates through the unit, the type of air cleaning technology used, and the technical design. Crucial to maximizing the efficiency of any in-room air cleaner is its strategic placement and set-up within a room, which should be done in consultation with ventilation engineers, infection control experts, and/or industrial hygienists. A poorly positioned air cleaner may disrupt airflow patterns within the room and through the air cleaner, thereby compromising its air cleaning efficiency. The effectiveness of an in-room air cleaner to remove airborne pathogens from room air depends on several factors, including the airflow rate through the unit's filter and the airflow patterns in the room. Tested under a variety of conditions, in-room air cleaners, including portable or ceiling mounted units with either a HEPA or a non-HEPA filter, portable units with UVGI lights only, or ceiling mounted units with combined HEPA filtration and UVGI lights, have been estimated to be between 30% and 90%, 99% and 12% and 80% effective, respectively. However, and although their effectiveness is variable, the United States Centers for Disease Control and Prevention has acknowledged in-room air cleaners as alternative technology for increasing room ventilation when this cannot be achieved by the building's HVAC system with preference given to fixed recirculating systems over portable ones. Importantly, the use of an in-room air cleaner does not preclude either the need for health care workers and visitors to use personal protective equipment (N95 mask or equivalent) when entering AII rooms or health care facilities from meeting current regulatory requirements for airflow rates (ventilation rates) in buildings and airflow differentials for effective negative-pressure rooms. The Plasmacluster ion technology, developed in 2000, is an air purification technology. Its manufacturer, Sharp Electronics Corporation, says that it can disable airborne microorganisms through the generation of both positive and negative ions. (1) The functional unit is the hydroxyl, which is a molecule comprised of one oxygen molecule and one hydrogen atom. Plasmacluster ion air purifier uses a multilayer filter system composed of a prefilter, a carbon filter, an antibacterial filter, and a HEPA filter, combined with an ion generator to purify the air. The ion generator uses an alternating plasma discharge to split water molecules into positively and negatively charged ions. When these ions are emitted into the air, they are surrounded by water molecules and form cluster ions which are attracted to airborne particles. The cluster ion surrounds the airborne particle, and the positive and negative ions react to form hydroxyls. These hydroxyls steal the airborne particle's hydrogen atom, which creates a hole in the particle's outer protein membrane, thereby rendering it inactive. Because influenza is primarily acquired by large droplets and direct and indirect contact with an infectious person, any in-room air cleaner will have little benefit in controlling and preventing its spread. Therefore, there is no role for the Plasmacluster ion air purifier or any other in-room air cleaner in the control of the spread of influenza. Accordingly, for purposes of this review, the Medical Advisory Secretariat presents no further analysis of the Plasmacluster. The objective of the systematic review was to determine the effectiveness of in-room air cleaners with built in UVGI lights and HEPA filtration compared with those using HEPA filtration only. The Medical Advisory Secretariat searched the databases of MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, INAHATA (International Network of Agencies for Health Technology Assessment), Biosis Previews, Bacteriology Abstracts, Web of Science, Dissertation Abstracts, and NIOSHTIC 2. A meta-analysis was conducted if adequate data was available from 2 or more studies and where statistical and clinical heterogeneity among studies was not an issue. Otherwise, a qualitative review was completed. The GRADE system was used to summarize the quality of the body of evidence comprised of 1 or more studies. There were no existing health technology assessments on air cleaning technology located during the literature review. The literature search yielded 59 citations of which none were retained. (ABSTRACT TRUNCATED)

Exploration Mission Particulate Matter Filtration Technology Performance Testing in a Simulated Spacecraft Cabin Ventilation System

NASA Technical Reports Server (NTRS)

Agui, Juan H.; Vijayakumar, R.; Perry, Jay L.; Frederick, Kenneth R.; Mccormick, Robert M.

2017-01-01

Human deep space exploration missions will require advances in long-life, low maintenance airborne particulate matter filtration technology. As one of the National Aeronautics and Space Administrations (NASA) developments in this area, a prototype of a new regenerable, multi-stage particulate matter filtration technology was tested in an International Space Station (ISS) module simulation facility. As previously reported, the key features of the filter system include inertial and media filtration with regeneration and in-place media replacement techniques. The testing facility can simulate aspects of the cabin environment aboard the ISS and contains flight-like cabin ventilation system components. The filtration technology test article was installed at the inlet of the central ventilation system duct and instrumented to provide performance data under nominal flow conditions. In-place regeneration operations were also evaluated. The real-time data included pressure drop across the filter stages, process air flow rate, ambient pressure, humidity and temperature. In addition, two video cameras positioned at the filtration technology test articles inlet and outlet were used to capture the mechanical performance of the filter media indexing operation under varying air flow rates. Recent test results are presented and future design recommendations are discussed.

High Efficiency, Transparent, Reusable, and Active PM2.5 Filters by Hierarchical Ag Nanowire Percolation Network.

PubMed

Jeong, Seongmin; Cho, Hyunmin; Han, Seonggeun; Won, Phillip; Lee, Habeom; Hong, Sukjoon; Yeo, Junyeob; Kwon, Jinhyeong; Ko, Seung Hwan

2017-07-12

Air quality has become a major public health issue in Asia including China, Korea, and India. Particulate matters are the major concern in air quality. We present the first environmental application demonstration of Ag nanowire percolation network for a novel, electrical type transparent, reusable, and active PM2.5 air filter although the Ag nanowire percolation network has been studied as a very promising transparent conductor in optoelectronics. Compared with previous particulate matter air filter study using relatively weaker short-range intermolecular force in polar polymeric nanofiber, Ag nanowire percolation network filters use stronger long-range electrostatic force to capture PM2.5, and they are highly efficient (>99.99%), transparent, working on an active mode, low power consumption, antibacterial, and reusable after simple washing. The proposed new particulate matter filter can be applied for a highly efficient, reusable, active and energy efficient filter for wearable electronics application.

Depletion of liver glutathione levels in rats: a potential confound of nose-only inhalation.

PubMed

Fechter, Laurence D; Nelson-Miller, Alisa; Gearhart, Caroline

2008-07-01

Nose-only inhalation exposure chambers offer key advantages to whole-body systems, particularly when aerosol or mixed aerosol-vapor exposures are used. Specifically, nose-only chambers provide enhanced control over the route of exposure and dose by minimizing the deposition of particles either on the subjects skin/fur or on surfaces of a whole-body exposure system. In the current series of experiments, liver, brain, and lung total glutathione (GSH) levels were assessed following either nose-only or whole-body exposures to either jet fuel or to clean, filtered air. The data were compared to untreated control subjects. Acute nose-only inhalation exposures of rats resulted in a significant depletion of liver GSH levels both in subjects that were exposed to clean, filtered air as well as those exposed to JP-8 jet fuel and to a synthetic jet fuel. Glutathione levels were not altered in lung or brain tissue. Whole-body inhalation exposure had no effect on GSH levels in any tissue for any of the treatment groups. A second experiment demonstrated that the loss of GSH did not occur if rats were anaesthetized prior to and during nose-only exposure to clean, filtered air or to mixed hydrocarbons. These data appear to be consistent with studies demonstrating depletion in liver GSH levels among rats subjected to restraint stress. Finally, the depletion of GSH that was observed in liver following a single acute exposure was reduced following five daily exposures to clean, filtered air, suggesting the possibility of habituation to restraint in the nose-only exposure chamber. The finding that placement in a nose-only exposure chamber per se yields liver GSH depletion raises the possibility of an interaction between this mode of toxicant exposure and the toxicological effects of certain inhaled test substances.

Analysis of the plugging of the systems autonomy demonstration project brassboard filters

NASA Technical Reports Server (NTRS)

Clay, John C.

1989-01-01

A fine gray powder was clogging the brassboard filters. The powder appeared to be residue from a galvanic corrosive attack by ammonia of the aluminum and stainless steel components in the system. The corrosion was caused by water and chlorine that had entered into the system and combined with the ammonia. This combination made an electrolyte and a corrosive agent of the ammonia that attacked the metals in the system. The corroded material traveled through the system with the ammonia and clogged the filters. Key conclusions are: the debris collecting in the filters is a by-product of galvanic corrosion; the debris is principally corroded aluminum and stainless from the system; and galvanic corrosion occurred from water and chlorine that entered the system during normal and/or extreme operating and servicing conditions. Key recommendations are: use only one metal in the ammonia system-titanium, aluminum, or stainless steel; make the system as air-tight as possible (replace fittings with welded joints); and replace electron paramagnetic resonance (EPR) O-rings with neoprene O-rings, and do not use freon to clean system components.

Activated charcoal filters: Water treatment, pollution control, and industrial applications. October 1970-October 1989 (Citations from the US Patent data base). Report for October 1970-October 1989

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

Not Available

This bibliography contains citations of selected patents concerning activated charcoal filters and their applications in water treatment, pollution control, and industrial processes. Filtering methods and equipment for air and water purification, industrial distillation and extraction, industrial leaching, and filtration of toxic materials and contaminants are described. Applications include drinking water purification, filtering beverages, production of polymer materials, solvent and metal recovery, waste conversion, automotive fuel and exhaust systems, swimming-pool filtration, tobacco-smoke filters, kitchen ventilators, medical filtration treatment, and odor-absorbing materials. (This updated bibliography contains 173 citations, 12 of which are new entries to the previous edition.)

Activated-charcoal filters: Water treatment, pollution control, and industrial applications. January 1970-August 1989 (Citations from the US Patent data base). Report for January 1970-August 1989

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

Not Available

This bibliography contains citations of selected patents concerning activated charcoal filters and their applications in water treatment, pollution control, and industrial processes. Filtering methods and equipment for air and water purification, industrial distillation and extraction, industrial leaching, and filtration of toxic materials and contaminants are described. Applications include drinking-water purification, filtering beverages, production of polymer materials, solvent and metal recovery, waste conversion, automotive fuel and exhaust systems, swimming-pool filtration, tobacco-smoke filters, kitchen ventilators, medical-filtration treatment, and odor absorbing materials. (This updated bibliography contains 161 citations, 32 of which are new entries to the previous edition.)

Investigation of the practical aspects of an additional 0.1 mm copper x-ray spectral filter for cine acquisition mode imaging in a clinical care setting.

PubMed

Fetterly, Kenneth A

2010-11-01

Minimizing the x-ray radiation dose is an important aspect of patient safety during interventional fluoroscopy procedures. This work investigates the practical aspects of an additional 0.1 mm Cu x-ray beam spectral filter applied to cine acquisition mode imaging on patient dose and image quality. Measurements were acquired using clinical interventional imaging systems. Acquisition images of Solid Water phantoms (15-40 cm) were acquired using x-ray beams with the x-ray tube inherent filtration and using an additional 0.1 mm Cu x-ray beam spectral filter. The skin entrance air kerma (dose) rate was measured and the signal difference to noise ratio (SDNR) of an iodine target embedded into the phantom was calculated to assess image quality. X-ray beam parameters were recorded and analyzed and a primary x-ray beam simulation was performed to assess additional x-ray tube burden attributable to the Cu filter. For all phantom thicknesses, the 0.1 mm Cu filter resulted in a 40% reduction in the entrance air kerma rate to the phantoms and a 9% reduction in the SDNR of the iodine phantom. The expected additional tube load required by the 0.1 mm Cu filter ranged from 11% for a 120 kVp x-ray beam to 43% for a 60 kVp beam. For these clinical systems, use of the 0.1 mm Cu filter resulted in a favorable compromise between reduced skin dose rate and image quality and increased x-ray tube burden.

Evaluating the Long-Term Health and Economic Impacts of Central Residential Air Filtration for Reducing Premature Mortality Associated with Indoor Fine Particulate Matter (PM2.5) of Outdoor Origin

PubMed Central

Zhao, Dan; Azimi, Parham; Stephens, Brent

2015-01-01

Much of human exposure to fine particulate matter (PM2.5) of outdoor origin occurs in residences. High-efficiency particle air filtration in central heating, ventilating, and air-conditioning (HVAC) systems is increasingly being used to reduce concentrations of particulate matter inside homes. However, questions remain about the effectiveness of filtration for reducing exposures to PM2.5 of outdoor origin and adverse health outcomes. Here we integrate epidemiology functions and mass balance modeling to estimate the long-term health and economic impacts of HVAC filtration for reducing premature mortality associated with indoor PM2.5 of outdoor origin in residences. We evaluate 11 classifications of filters (MERV 5 through HEPA) using six case studies of single-family home vintages and ventilation system combinations located in 22 U.S. cities. We estimate that widespread use of higher efficiency filters would reduce premature mortality by 0.002–2.5% and increase life expectancy by 0.02–1.6 months, yielding annual monetary benefits ranging from $1 to $1348 per person in the homes and locations modeled herein. Large differences in the magnitude of health and economic impacts are driven largely by differences in rated filter efficiency and building and ventilation system characteristics that govern particle infiltration and persistence, with smaller influences attributable to geographic location. PMID:26197328

Evaluating the Long-Term Health and Economic Impacts of Central Residential Air Filtration for Reducing Premature Mortality Associated with Indoor Fine Particulate Matter (PM2.5) of Outdoor Origin.

PubMed

Zhao, Dan; Azimi, Parham; Stephens, Brent

2015-07-21

Much of human exposure to fine particulate matter (PM2.5) of outdoor origin occurs in residences. High-efficiency particle air filtration in central heating, ventilating, and air-conditioning (HVAC) systems is increasingly being used to reduce concentrations of particulate matter inside homes. However, questions remain about the effectiveness of filtration for reducing exposures to PM2.5 of outdoor origin and adverse health outcomes. Here we integrate epidemiology functions and mass balance modeling to estimate the long-term health and economic impacts of HVAC filtration for reducing premature mortality associated with indoor PM2.5 of outdoor origin in residences. We evaluate 11 classifications of filters (MERV 5 through HEPA) using six case studies of single-family home vintages and ventilation system combinations located in 22 U.S. cities. We estimate that widespread use of higher efficiency filters would reduce premature mortality by 0.002-2.5% and increase life expectancy by 0.02-1.6 months, yielding annual monetary benefits ranging from $1 to $1348 per person in the homes and locations modeled herein. Large differences in the magnitude of health and economic impacts are driven largely by differences in rated filter efficiency and building and ventilation system characteristics that govern particle infiltration and persistence, with smaller influences attributable to geographic location.

PubMed search filters for the study of putative outdoor air pollution determinants of disease

PubMed Central

Curti, Stefania; Gori, Davide; Di Gregori, Valentina; Farioli, Andrea; Baldasseroni, Alberto; Fantini, Maria Pia; Christiani, David C; Violante, Francesco S; Mattioli, Stefano

2016-01-01

Objectives Several PubMed search filters have been developed in contexts other than environmental. We aimed at identifying efficient PubMed search filters for the study of environmental determinants of diseases related to outdoor air pollution. Methods We compiled a list of Medical Subject Headings (MeSH) and non-MeSH terms seeming pertinent to outdoor air pollutants exposure as determinants of diseases in the general population. We estimated proportions of potentially pertinent articles to formulate two filters (one ‘more specific’, one ‘more sensitive’). Their overall performance was evaluated as compared with our gold standard derived from systematic reviews on diseases potentially related to outdoor air pollution. We tested these filters in the study of three diseases potentially associated with outdoor air pollution and calculated the number of needed to read (NNR) abstracts to identify one potentially pertinent article in the context of these diseases. Last searches were run in January 2016. Results The ‘more specific’ filter was based on the combination of terms that yielded a threshold of potentially pertinent articles ≥40%. The ‘more sensitive’ filter was based on the combination of all search terms under study. When compared with the gold standard, the ‘more specific’ filter reported the highest specificity (67.4%; with a sensitivity of 82.5%), while the ‘more sensitive’ one reported the highest sensitivity (98.5%; with a specificity of 47.9%). The NNR to find one potentially pertinent article was 1.9 for the ‘more specific’ filter and 3.3 for the ‘more sensitive’ one. Conclusions The proposed search filters could help healthcare professionals investigate environmental determinants of medical conditions that could be potentially related to outdoor air pollution. PMID:28003291

Effectiveness and cost of reducing particle-related mortality with particle filtration

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

Fisk, W. J.; Chan, W. R.

This study evaluates the mortality-related benefits and costs of improvements in particle filtration in U.S. homes and commercial buildings based on models with empirical inputs. The models account for time spent in various environments as well as activity levels and associated breathing rates. The scenarios evaluated include improvements in filter efficiencies in both forced-air heating and cooling systems of homes and heating, ventilating, and air conditioning systems of workplaces as well as use of portable air cleaners in homes. The predicted reductions in mortality range from approximately 0.25 to 2.4 per 10 000 population. The largest reductions in mortality were frommore » interventions with continuously operating portable air cleaners in homes because, given our scenarios, these portable air cleaners with HEPA filters most reduced particle exposures. For some interventions, predicted annual mortality-related economic benefits exceed $1000 per person. Economic benefits always exceed costs with benefit-to-cost ratios ranging from approximately 3.9 to 133. In conclusion, restricting interventions to homes of the elderly further increases the mortality reductions per unit population and the benefit-to-cost ratios.« less

Impact of asthma, exposure period, and filters on human responses during exposures to ozone and its initiated chemistry products.

PubMed

Fadeyi, M O; Tham, K W; Wu, W Y

2015-10-01

The impact of asthma, exposure period, and filter condition downstream of the mixing box of air-conditioning system on building occupants' perceptual response, work performance, and salivary α-amylase secretion during exposures to ozone and its initiated chemistry products is studied. The experiments were conducted in a field environmental chamber (FEC) (240 m(3)) simulating an office environment. Experiments were conducted during periods when the air-handling system operated with new or used pleated panel filters at constant recirculation (7/h) and ventilation (1/h) rates. Average ozone and secondary organic aerosols (ozone-initiated chemistry products) measured during non-asthmatic and asthmatic subjects' 3-h exposures in the FEC were in the ranges approximately 20-37 ppb and approximately 1.6-3 μg/m(3), respectively. Asthmatic subjects' perceived odor intensity and sensory (eye, nose, and throat) irritation ratings were generally lower than those of non-asthmatic subjects, possibly explaining why asthmatic subjects accept perceived air quality more than non-asthmatic subjects. However, asthmatic subjects' perceived physiological-like symptom ratings (flu, chest tightness, and headache) and concentrations of secreted salivary α-amylase were generally higher than those of non-asthmatic subjects. Asthmatic subjects had significantly lower accuracy than non-asthmatic subjects in a task that required higher concentration although they had higher work speed. Filter condition did not make any significant difference for subjects' responses. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

PCR Testing of IVC Filter Tops as a Method for Detecting Murine Pinworms and Fur Mites.

PubMed

Gerwin, Philip M; Ricart Arbona, Rodolfo J; Riedel, Elyn R; Henderson, Kenneth S; Lipman, Neil S

2017-11-01

We evaluated PCR testing of filter tops from cages maintained on an IVC system through which exhaust air is filtered at the cage level as a method for detecting parasite-infected and -infested cages. Cages containing 4 naïve Swiss Webster mice received 360 mL of uncontaminated aspen chip or α-cellulose bedding (n = 18 cages each) and 60 mL of the same type of bedding weekly from each of the following 4 groups of cages housing mice infected or infested with Syphacia obvelata (SO), Aspiculuris tetraptera (AT), Myocoptes musculinus (MC), or Myobia musculi (MB) and Radfordia affinis (RA; 240 mL bedding total). Detection rates were compared at 30, 60, and 90 d after initiating bedding exposure, by using PCR analysis of filter tops (media extract and swabs) and testing of mouse samples (fur swab [direct] PCR testing, fecal flotation, anal tape test, direct examination of intestinal contents, and skin scrape). PCR testing of filter media extract detected 100% of all parasites at 30 d (both bedding types) except for AT (α-cellulose bedding, 67% detection rate); identified more cages with fur mites (MB and MC) than direct PCR when cellulose bedding was used; and was better at detecting parasites than all nonmolecular methods evaluated. PCR analysis of filter media extract was superior to swab and direct PCR for all parasites cumulatively for each bedding type. Direct PCR more effectively detected MC and all parasites combined for aspen chip compared with cellulose bedding. PCR analysis of filter media extract for IVC systems in which exhaust air is filtered at the cage level was shown to be a highly effective environmental testing method.

PCR Testing of IVC Filter Tops as a Method for Detecting Murine Pinworms and Fur Mites

PubMed Central

Gerwin, Philip M; Arbona, Rodolfo J Ricart; Riedel, Elyn R; Henderson, Kenneth S; Lipman, Neil S

2017-01-01

We evaluated PCR testing of filter tops from cages maintained on an IVC system through which exhaust air is filtered at the cage level as a method for detecting parasite- infected and -infested cages. Cages containing 4 naïve Swiss Webster mice received 360 mL of uncontaminated aspen chip or α-cellulose bedding (n = 18 cages each) and 60 mL of the same type of bedding weekly from each of the following 4 groups of cages housing mice infected or infested with Syphacia obvelata (SO), Aspiculuris tetraptera (AT), Myocoptes musculinus (MC), or Myobia musculi (MB) and Radfordia affinis (RA; 240 mL bedding total). Detection rates were compared at 30, 60, and 90 d after initiating bedding exposure, by using PCR analysis of filter tops (media extract and swabs) and testing of mouse samples (fur swab [direct] PCR testing, fecal flotation, anal tape test, direct examination of intestinal contents, and skin scrape). PCR testing of filter media extract detected 100% of all parasites at 30 d (both bedding types) except for AT (α-cellulose bedding, 67% detection rate); identified more cages with fur mites (MB and MC) than direct PCR when cellulose bedding was used; and was better at detecting parasites than all nonmolecular methods evaluated. PCR analysis of filter media extract was superior to swab and direct PCR for all parasites cumulatively for each bedding type. Direct PCR more effectively detected MC and all parasites combined for aspen chip compared with cellulose bedding. PCR analysis of filter media extract for IVC systems in which exhaust air is filtered at the cage level was shown to be a highly effective environmental testing method. PMID:29256370

76 FR 13661 - In the Matter of Certain Connecting Devices (“Quick Clamps”) for Use With Modular Compressed Air...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-03-14

... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-587] In the Matter of Certain Connecting Devices (``Quick Clamps'') for Use With Modular Compressed Air Conditioning Units, Including Filters, Regulators, and Lubricators (``FRL's'') That Are Part of Larger Pneumatic Systems and the FRL Units They...

75 FR 63198 - In the Matter of Certain Connecting Devices (“Quick Clamps”) for Use With Modular Compressed Air...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-10-14

... INTERNATIONAL TRADE COMMISSION [Investigation No. 337-TA-587] In the Matter of Certain Connecting Devices (``Quick Clamps'') for Use With Modular Compressed Air Conditioning Units, Including Filters, Regulators, and Lubricators (``Frl's'') That Are Part of Larger Pneumatic Systems and the FRL Units They...

75 FR 24945 - Agency Information Collection Activities; Submission to OMB for Review and Approval; Comment...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-06

... Emission Standards for Hazardous Air Pollutants (NESHAP) for Mineral Wool Production (40 CFR part 63... wool production plants are required to install fabric filter bag leak detection systems and then... Air Act. The required information consists of emissions data and other information that have been...

40 CFR 62.14690 - What monitoring equipment must I install and what parameters must I monitor?

Code of Federal Regulations, 2012 CFR

2012-07-01

... each baghouse compartment or cell. For negative pressure or induced air fabric filters, the bag leak... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF STATE PLANS... subpart, you must install, calibrate, maintain, and continuously operate a bag leak detection system as...

40 CFR 62.14690 - What monitoring equipment must I install and what parameters must I monitor?

Code of Federal Regulations, 2014 CFR

2014-07-01

... each baghouse compartment or cell. For negative pressure or induced air fabric filters, the bag leak... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF STATE PLANS... subpart, you must install, calibrate, maintain, and continuously operate a bag leak detection system as...

40 CFR 62.14690 - What monitoring equipment must I install and what parameters must I monitor?

Code of Federal Regulations, 2013 CFR

2013-07-01

... each baghouse compartment or cell. For negative pressure or induced air fabric filters, the bag leak... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) APPROVAL AND PROMULGATION OF STATE PLANS... subpart, you must install, calibrate, maintain, and continuously operate a bag leak detection system as...

75 FR 26898 - Determination of Attainment for PM-10; Fort Hall PM-10 Nonattainment Area, Idaho

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-13

... 2009. \\9\\ FRMs are manual samplers that pull air through a filter for 24 hours (midnight to midnight... of the filter and the volume of air drawn through it. In 2008, an additional filter-based PM-10... Agency (EPA). ACTION: Proposed rule. SUMMARY: EPA is proposing under the Clean Air Act (CAA) to determine...

40 CFR 721.10575 - 1-Propanone, 1,1'-(oxydi-4,1-phenylene)bis[2-hydroxy-2-methyl-.

Code of Federal Regulations, 2013 CFR

2013-07-01

...), R100, or P100 filters. (B) NIOSH-certified air-purifying, tight-fitting full-face respirator equipped with N100 (if oil aerosols absent), R100, or P100 filters. (C) NIOSH-certified powered air-purifying respirator equipped with a loose-fitting hood or helmet and high efficiency particulate air (HEPA) filters...

40 CFR 721.10575 - 1-Propanone, 1,1'-(oxydi-4,1-phenylene)bis[2-hydroxy-2-methyl-.

Code of Federal Regulations, 2014 CFR

2014-07-01

...), R100, or P100 filters. (B) NIOSH-certified air-purifying, tight-fitting full-face respirator equipped with N100 (if oil aerosols absent), R100, or P100 filters. (C) NIOSH-certified powered air-purifying respirator equipped with a loose-fitting hood or helmet and high efficiency particulate air (HEPA) filters...

122. View in subway showing air filters for unit turbinegenerator ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

122. View in subway showing air filters for unit turbine-generator unit no. 3; looking north. To the left is opening through wall which brings fresh air into the filters; this opening is above the tailrace. Photo by Jet Lowe, HAER, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

Infiltration of forest fire and residential wood smoke: an evaluation of air cleaner effectiveness.

PubMed

Barn, Prabjit; Larson, Timothy; Noullett, Melanie; Kennedy, Susan; Copes, Ray; Brauer, Michael

2008-09-01

Communities impacted by fine-particle air pollution (particles with an aerodynamic diameter less than 2.5 microm; PM(2.5)) from forest fires and residential wood burning require effective, evidence-based exposure-reduction strategies. Public health recommendations during smoke episodes typically include advising community members to remain indoors and the use of air cleaners, yet little information is available on the effectiveness of these measures. Our study attempted to address the following objectives: to measure indoor infiltration factor (F(inf)) of PM(2.5) from forest fires/wood smoke, to determine the effectiveness of high-efficiency particulate air (HEPA) filter air cleaners in reducing indoor PM(2.5), and to analyze the home determinants of F(inf) and air cleaner effectiveness (ACE). We collected indoor/outdoor 1-min PM(2.5) averages and 48-h outdoor PM(2.5) filter samples for 21 winter and 17 summer homes impacted by wood burning and forest fire smoke, respectively, during 2004-2005. A portable HEPA filter air cleaner was operated indoors with the filter removed for one of two sampling days. Particle F(inf) and ACE were calculated for each home using a recursive model. We found mean F(inf)+/-SD was 0.27+/-0.18 and 0.61+/-0.27 in winter (n=19) and summer (n=13), respectively, for days when HEPA filters were not used. Lower F(inf)+/-SD values of 0.10+/-0.08 and 0.19+/-0.20 were found on corresponding days when HEPA filters were in place. Mean+/-SD ACE ([F(inf) without filter-F(inf) with filter]/F(inf) without filter) in winter and summer were 55+/-38% and 65+/-35%, respectively. Number of windows and season predicted F(inf) (P<0.001). No significant predictors of ACE were identified. Our findings show that remaining indoors combined with use of air cleaner can effectively reduce PM(2.5) exposure during forest fires and residential wood burning.

Mold occurring on the air cleaner high-efficiency particulate air filters used in the houses of child patients with atopic dermatitis.

PubMed

Kim, Seong Hwan; Ahn, Geum Ran; Son, Seung Yeol; Bae, Gwi-Nam; Yun, Yeo Hong

2014-09-01

Fungi are the known sources of irritation associated with atopic diseases (e.g., asthma, allergic rhinoconjunctivitis, and atopic eczema). To quantitatively estimate their presence in the indoor environment of atopic dermatitis-inflicted child patient's houses (ADCPHs), the high-efficiency particulate air (HEPA) filters installed inside the air cleaners of three different ADCPHs were investigated for the presence of mold. The air cleaner HEPA filters obtained from the three different ADCPHs were coded as HEPA-A, -B, and -C, respectively, and tested for the presence of mold. The colony forming units (CFUs) corresponding to the HEPA-A, -B, and -C filters were estimated to be 6.51 × 10(2) ± 1.50 × 10(2) CFU/cm(2), 8.72 × 10(2) ± 1.69 × 10(2) CFU/cm(2), and 9.71 × 10(2) ± 1.35 × 10(2) CFU/cm(2), respectively. Aspergillus, Penicillium, Alternaria, Cladosporium, Trichoderma, and other fungal groups were detected in the 2,494 isolates. The distribution of these fungal groups differed among the three filters. Cladosporium was the major fungal group in filters HEPA-A and -C, whereas Penicillium was the major fungal group in the filter HEPA-B. Nine fungal species, including some of the known allergenic species, were identified in these isolates. Cladosporium cladosporioides was the most common mold among all the three filters. This is the first report on the presence of fungi in the air cleaner HEPA filters from ADCPHs in Korea.

Anti-air pollution & energy conservation system for automobiles using leaded or unleaded gasoline, diesel or alternate fuel

DOEpatents

Bose, Ranendra K.

2002-06-04

Exhaust gases from an internal combustion engine operating with leaded or unleaded gasoline or diesel or natural gas, are used for energizing a high-speed gas turbine. The convoluting gas discharge causes a first separation stage by stratifying of heavier and lighter exhaust gas components that exit from the turbine in opposite directions, the heavier components having a second stratifying separation in a vortex tube to separate combustible pollutants from non-combustible components. The non-combustible components exit a vortex tube open end to atmosphere. The lighter combustible, pollutants effected in the first separation are bubbled through a sodium hydroxide solution for dissolving the nitric oxide, formaldehyde impurities in this gas stream before being piped to the engine air intake for re-combustion, thereby reducing the engine's exhaust pollution and improving its fuel economy. The combustible, heavier pollutants from the second separation stage are piped to air filter assemblies. This gas stream convoluting at a high-speed through the top stator-vanes of the air filters, centrifugally separates the coalescent water, aldehydes, nitrogen dioxides, sulfates, sulfur, lead particles which collect at the bottom of the bowl, wherein it is periodically released to the roadway. Whereas, the heavier hydrocarbon, carbon particles are piped through the air filter's porous element to the engine air intake for re-combustion, further reducing the engine's exhaust pollution and improving its fuel economy.

Chronic exposure to air pollution particles increases the risk of obesity and metabolic syndrome: findings from a natural experiment in Beijing.

PubMed

Wei, Yongjie; Zhang, Junfeng Jim; Li, Zhigang; Gow, Andrew; Chung, Kian Fan; Hu, Min; Sun, Zhongsheng; Zeng, Limin; Zhu, Tong; Jia, Guang; Li, Xiaoqian; Duarte, Marlyn; Tang, Xiaoyan

2016-06-01

Epidemiologic evidence suggests that air pollution is a risk factor for childhood obesity. Limited experimental data have shown that early-life exposure to ambient particles either increases susceptibility to diet-induced weight gain in adulthood or increases insulin resistance, adiposity, and inflammation. However, no data have directly supported a link between air pollution and non-diet-induced weight increases. In a rodent model, we found that breathing Beijing's highly polluted air resulted in weight gain and cardiorespiratory and metabolic dysfunction. Compared to those exposed to filtered air, pregnant rats exposed to unfiltered Beijing air were significantly heavier at the end of pregnancy. At 8 wk old, the offspring prenatally and postnatally exposed to unfiltered air were significantly heavier than those exposed to filtered air. In both rat dams and their offspring, after continuous exposure to unfiltered air we observed pronounced histologic evidence for both perivascular and peribronchial inflammation in the lungs, increased tissue and systemic oxidative stress, dyslipidemia, and an enhanced proinflammatory status of epididymal fat. Results suggest that TLR2/4-dependent inflammatory activation and lipid oxidation in the lung can spill over systemically, leading to metabolic dysfunction and weight gain.-Wei, Y., Zhang, J., Li, Z., Gow, A., Chung, K. F., Hu, M., Sun, Z., Zeng, L., Zhu, T., Jia, G., Li, X., Duarte, M., Tang, X. Chronic exposure to air pollution particles increases the risk of obesity and metabolic syndrome: findings from a natural experiment in Beijing. © FASEB.

System optimization of a field-widened Michelson interferometric spectral filter for high spectral resolution lidar

NASA Astrophysics Data System (ADS)

Liu, Dong; Miller, Ian; Hostetler, Chris; Cook, Anthony; Hair, Johnathan

2011-06-01

High spectral resolution lidars (HSRLs) have recently shown great value in aerosol measurements form aircraft and are being called for in future space-based aerosol remote sensing applications. A quasi-monolithic field-widened, off-axis Michelson interferometer had been developed as the spectral discrimination filter for an HSRL currently under development at NASA Langley Research Center (LaRC). The Michelson filter consists of a cubic beam splitter, a solid arm and an air arm. The input light is injected at 1.5° off-axis to provide two output channels: standard Michelson output and the reflected complementary signal. Piezo packs connect the air arm mirror to the main part of the filter that allows it to be tuned within a small range. In this paper, analyses of the throughput wavephase, locking error, AR coating, and tilt angle of the interferometer are described. The transmission ratio for monochromatic light at the transmitted wavelength is used as a figure of merit for assessing each of these parameters.

A comparative study of sensor fault diagnosis methods based on observer for ECAS system

NASA Astrophysics Data System (ADS)

Xu, Xing; Wang, Wei; Zou, Nannan; Chen, Long; Cui, Xiaoli

2017-03-01

The performance and practicality of electronically controlled air suspension (ECAS) system are highly dependent on the state information supplied by kinds of sensors, but faults of sensors occur frequently. Based on a non-linearized 3-DOF 1/4 vehicle model, different methods of fault detection and isolation (FDI) are used to diagnose the sensor faults for ECAS system. The considered approaches include an extended Kalman filter (EKF) with concise algorithm, a strong tracking filter (STF) with robust tracking ability, and the cubature Kalman filter (CKF) with numerical precision. We propose three filters of EKF, STF, and CKF to design a state observer of ECAS system under typical sensor faults and noise. Results show that three approaches can successfully detect and isolate faults respectively despite of the existence of environmental noise, FDI time delay and fault sensitivity of different algorithms are different, meanwhile, compared with EKF and STF, CKF method has best performing FDI of sensor faults for ECAS system.

Formaldehyde emissions from ventilation filters under different relative humidity conditions.

PubMed

Sidheswaran, Meera; Chen, Wenhao; Chang, Agatha; Miller, Robert; Cohn, Sebastian; Sullivan, Douglas; Fisk, William J; Kumagai, Kazukiyo; Destaillats, Hugo

2013-05-21

Formaldehyde emissions from fiberglass and polyester filters used in building heating, ventilation, and air conditioning (HVAC) systems were measured in bench-scale tests using 10 and 17 cm(2) coupons over 24 to 720 h periods. Experiments were performed at room temperature and four different relative humidity settings (20, 50, 65, and 80% RH). Two different air flow velocities across the filters were explored: 0.013 and 0.5 m/s. Fiberglass filters emitted between 20 and 1000 times more formaldehyde than polyester filters under similar RH and airflow conditions. Emissions increased markedly with increasing humidity, up to 10 mg/h-m(2) at 80% RH. Formaldehyde emissions from fiberglass filters coated with tackifiers (impaction oils) were lower than those from uncoated fiberglass media, suggesting that hydrolysis of other polymeric constituents of the filter matrix, such as adhesives or binders was likely the main formaldehyde source. These laboratory results were further validated by performing a small field study in an unoccupied office. At 80% RH, indoor formaldehyde concentrations increased by 48-64%, from 9-12 μg/m(3) to 12-20 μg/m(3), when synthetic filters were replaced with fiberglass filtration media in the HVAC units. Better understanding of the reaction mechanisms and assessing their overall contributions to indoor formaldehyde levels will allow for efficient control of this pollution source.

[Appropriate dust control measures for jade carving operations].

PubMed

Liu, Jiang; Wang, Qiushui; Liu, Guangquan

2002-12-01

To provide the appropriate dust control measures for jade carving operations. Dust concentrations in the workplace were measured according to GB/T 5748-85. Ventilation system of dust control were measured according to GB/T 16157-1996. Dust particle size distributions for different sources and particle size fraction collecting efficiencies of the dust collectors were measured with WY-1 in-stack 7 stage cascade impactors. On the basis of adopting wet process in the carving operations, local exhaust ventilation system for dust control was installed, which included: the special designed slot exhaust hoods with hood face velocity of 2.5 m/s and exhaust volume of 600 m3/h. The pipe sizes were determined according to the air volume passing through the pipe and the reasonable air velocities. Impinging scrubber or bag filter dust collector were selected to treat the dust laden air from the local exhaust ventilation system, which gave a total collecting efficiency of 97% for impinging scrubber and 98% for bag filter; The type of fan and its size were selected according to the total air volume of the ventilation system and maximum total pressure needed for the longest pipe line plus the pressure drop of the dust collector. Practical application showed that, after installation and use of the appropriate dust control measures, the dust concentrations in the workplaces could meet or nearly meet the national hygienic standard and the dust laden air at the local exhaust ventilation system could meet the national emission standard.

Application of acoustic agglomeration to enhance air filtration efficiency in air-conditioning and mechanical ventilation (ACMV) systems.

PubMed

Ng, Bing Feng; Xiong, Jin Wen; Wan, Man Pun

2017-01-01

The recent episodes of haze in Southeast Asia have caused some of the worst regional atmospheric pollution ever recorded in history. In order to control the levels of airborne fine particulate matters (PM) indoors, filtration systems providing high PM capturing efficiency are often sought, which inadvertently also results in high airflow resistance (or pressure drop) that increases the energy consumption for air distribution. A pre-conditioning mechanism promoting the formation of particle clusters to enhance PM capturing efficiency without adding flow resistance in the air distribution ductwork could provide an energy-efficient solution. This pre-conditioning mechanism can be fulfilled by acoustic agglomeration, which is a phenomenon that promotes the coagulation of suspended particles by acoustic waves propagating in the fluid medium. This paper discusses the basic mechanisms of acoustic agglomeration along with influencing factors that could affect the agglomeration efficiency. The feasibility to apply acoustic agglomeration to improve filtration in air-conditioning and mechanical ventilation (ACMV) systems is investigated experimentally in a small-scale wind tunnel. Experimental results indicate that this novel application of acoustic pre-conditioning improves the PM2.5 filtration efficiency of the test filters by up to 10% without introducing additional pressure drop. The fan energy savings from not having to switch to a high capturing efficiency filter largely outstrip the additional energy consumed by the acoustics system. This, as a whole, demonstrates potential energy savings from the combined acoustic-enhanced filtration system without compromising on PM capturing efficiency.

Application of acoustic agglomeration to enhance air filtration efficiency in air-conditioning and mechanical ventilation (ACMV) systems

PubMed Central

Xiong, Jin Wen; Wan, Man Pun

2017-01-01

The recent episodes of haze in Southeast Asia have caused some of the worst regional atmospheric pollution ever recorded in history. In order to control the levels of airborne fine particulate matters (PM) indoors, filtration systems providing high PM capturing efficiency are often sought, which inadvertently also results in high airflow resistance (or pressure drop) that increases the energy consumption for air distribution. A pre-conditioning mechanism promoting the formation of particle clusters to enhance PM capturing efficiency without adding flow resistance in the air distribution ductwork could provide an energy-efficient solution. This pre-conditioning mechanism can be fulfilled by acoustic agglomeration, which is a phenomenon that promotes the coagulation of suspended particles by acoustic waves propagating in the fluid medium. This paper discusses the basic mechanisms of acoustic agglomeration along with influencing factors that could affect the agglomeration efficiency. The feasibility to apply acoustic agglomeration to improve filtration in air-conditioning and mechanical ventilation (ACMV) systems is investigated experimentally in a small-scale wind tunnel. Experimental results indicate that this novel application of acoustic pre-conditioning improves the PM2.5 filtration efficiency of the test filters by up to 10% without introducing additional pressure drop. The fan energy savings from not having to switch to a high capturing efficiency filter largely outstrip the additional energy consumed by the acoustics system. This, as a whole, demonstrates potential energy savings from the combined acoustic-enhanced filtration system without compromising on PM capturing efficiency. PMID:28594862