Science.gov

Sample records for 1-hour ozone standard

  1. 40 CFR 50.9 - National 1-hour primary and secondary ambient air quality standards for ozone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... ambient air quality standards for ozone. 50.9 Section 50.9 Protection of Environment ENVIRONMENTAL....9 National 1-hour primary and secondary ambient air quality standards for ozone. (a) The level of the national 1-hour primary and secondary ambient air quality standards for ozone measured by...

  2. 40 CFR 50.9 - National 1-hour primary and secondary ambient air quality standards for ozone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... ambient air quality standards for ozone. 50.9 Section 50.9 Protection of Environment ENVIRONMENTAL....9 National 1-hour primary and secondary ambient air quality standards for ozone. (a) The level of the national 1-hour primary and secondary ambient air quality standards for ozone measured by...

  3. 40 CFR 50.9 - National 1-hour primary and secondary ambient air quality standards for ozone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... ambient air quality standards for ozone. 50.9 Section 50.9 Protection of Environment ENVIRONMENTAL....9 National 1-hour primary and secondary ambient air quality standards for ozone. (a) The level of the national 1-hour primary and secondary ambient air quality standards for ozone measured by...

  4. 40 CFR 50.9 - National 1-hour primary and secondary ambient air quality standards for ozone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ambient air quality standards for ozone. 50.9 Section 50.9 Protection of Environment ENVIRONMENTAL....9 National 1-hour primary and secondary ambient air quality standards for ozone. (a) The level of the national 1-hour primary and secondary ambient air quality standards for ozone measured by...

  5. 40 CFR 50.9 - National 1-hour primary and secondary ambient air quality standards for ozone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... ambient air quality standards for ozone. 50.9 Section 50.9 Protection of Environment ENVIRONMENTAL....9 National 1-hour primary and secondary ambient air quality standards for ozone. (a) The level of the national 1-hour primary and secondary ambient air quality standards for ozone measured by...

  6. Guidance on Developing Fee Programs Required by Clean Air Act Section 185 for the 1997 1-hour Ozone National Ambient Air Quality Standards (NAAQS)

    EPA Pesticide Factsheets

    This January 2010 memorandum provides additional guidance on fee collection programs for the 1997 1-hour ozone NAAQS, which are required as anti-backsliding measures during transition to the 1997 8-hour ozone standard.

  7. 77 FR 64036 - Determination of Attainment of the 1-Hour Ozone National Ambient Air Quality Standards in the...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-18

    ...-hour ozone NAAQS or standard), and to exclude certain 2008 data caused by wildfire exceptional events... occurred due to wildfire exceptional events in 2008.\\1\\ In making its proposed determination, EPA proposed... ozone exceptional events that are caused by wildfires. These air quality determinations were...

  8. 76 FR 28661 - Interim Final Determination To Defer Sanctions, Sacramento Metro 1-Hour Ozone Nonattainment Area...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-18

    ... AGENCY 40 CFR Part 52 Interim Final Determination To Defer Sanctions, Sacramento Metro 1-Hour Ozone... the Sacramento Metro 1- hour Ozone nonattainment area (Sacramento Metro Area) to satisfy anti- backsliding requirements for the 1-hour Ozone standard. DATES: This interim final determination is...

  9. 40 CFR Appendix H to Part 50 - Interpretation of the 1-Hour Primary and Secondary National Ambient Air Quality Standards for Ozone

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... and Secondary National Ambient Air Quality Standards for Ozone H Appendix H to Part 50 Protection of... Secondary National Ambient Air Quality Standards for Ozone 1. General This appendix explains how to... associated examples are contained in the “Guideline for Interpretation of Ozone Air Quality Standards.”...

  10. 40 CFR Appendix H to Part 50 - Interpretation of the 1-Hour Primary and Secondary National Ambient Air Quality Standards for Ozone

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... and Secondary National Ambient Air Quality Standards for Ozone H Appendix H to Part 50 Protection of... Secondary National Ambient Air Quality Standards for Ozone 1. General This appendix explains how to... associated examples are contained in the “Guideline for Interpretation of Ozone Air Quality Standards.”...

  11. 40 CFR Appendix H to Part 50 - Interpretation of the 1-Hour Primary and Secondary National Ambient Air Quality Standards for Ozone

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... and Secondary National Ambient Air Quality Standards for Ozone H Appendix H to Part 50 Protection of... Secondary National Ambient Air Quality Standards for Ozone 1. General This appendix explains how to... associated examples are contained in the “Guideline for Interpretation of Ozone Air Quality Standards.”...

  12. 40 CFR Appendix H to Part 50 - Interpretation of the 1-Hour Primary and Secondary National Ambient Air Quality Standards for Ozone

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... and Secondary National Ambient Air Quality Standards for Ozone H Appendix H to Part 50 Protection of... Secondary National Ambient Air Quality Standards for Ozone 1. General This appendix explains how to... associated examples are contained in the “Guideline for Interpretation of Ozone Air Quality Standards.”...

  13. 40 CFR Appendix H to Part 50 - Interpretation of the 1-Hour Primary and Secondary National Ambient Air Quality Standards for Ozone

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... and Secondary National Ambient Air Quality Standards for Ozone H Appendix H to Part 50 Protection of... Secondary National Ambient Air Quality Standards for Ozone 1. General This appendix explains how to... associated examples are contained in the “Guideline for Interpretation of Ozone Air Quality Standards.”...

  14. 75 FR 232 - Finding of Failure To Submit Certain State Implementation Plans Required for the 1-Hour Ozone NAAQS

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-05

    ... Ozone NAAQS AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule. SUMMARY: The EPA is... Implementation Plans (SIPs) for three ozone nonattainment areas to satisfy certain requirements of the Clean Air Act (CAA) for the 1-hour ozone National Ambient Air Quality Standards (NAAQS). To accompany...

  15. 75 FR 51960 - Proposed Rule To Implement the 1997 8-Hour Ozone National Ambient Air Quality Standard: New...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-24

    ... AGENCY 40 CFR Part 51 RIN 2060-AP30 Proposed Rule To Implement the 1997 8-Hour Ozone National Ambient Air Quality Standard: New Source Review Anti-Backsliding Provisions for Former 1-Hour Ozone Standard AGENCY... designated nonattainment for the 1997 8-hour ozone national ambient air quality standard (NAAQS). The...

  16. 75 FR 57220 - Rule To Implement the 1997 8-Hour Ozone National Ambient Air Quality Standard: New Source Review...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-20

    ... AGENCY 40 CFR Part 51 RIN 2060-AP30 Rule To Implement the 1997 8-Hour Ozone National Ambient Air Quality Standard: New Source Review Anti-Backsliding Provisions for Former 1-Hour Ozone Standard--Public Hearing... is announcing a public hearing to be held for the proposed ``Rule to Implement the 1997 8-Hour...

  17. 78 FR 34177 - Implementation of the 2008 National Ambient Air Quality Standards for Ozone: State Implementation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-06

    ... the 2008 National Ambient Air Quality Standards for Ozone: State Implementation Plan Requirements... Ambient Air Quality Standards for Ozone: State Implementation Plan Requirements AGENCY: Environmental... 2008 ozone national ambient air quality standards (NAAQS) (the ``2008 ozone NAAQS'') that...

  18. A new ozone standard - The vapor pressure of ozone at liquid argon temperatures

    NASA Technical Reports Server (NTRS)

    Mauersberger, K.; Hanson, D.; Morton, J.

    1985-01-01

    The vapor pressure of ozone has been measured at liquid argon temperatures. At the normal boiling point of argon (-185.9 C) an ozone pressure of 0.0405 torr was obtained with an accuracy of + or - 1.5 percent. Increases and decreases in liquid argon temperatures raised and lowered the ozone vapor pressure, respectively. During the vapor pressure measurements the purity of ozone was monitored with a mass spectrometer. The proposed ozone standard will considerably improve the calibration of experiments for atmospheric research, the determination of absorption cross sections and other laboratory ozone studies.

  19. Setting and Reviewing Standards to Control Ozone Pollution

    EPA Pesticide Factsheets

    Ozone standards are part of the National Ambient Air Quality Standards (NAAQS), which limit air pollution to protect health and the environment. Standards are periodically reviewed and updated, and air quality across the U.S. is measured against them.

  20. 77 FR 34810 - Determination of Failure To Attain by 2005 and Determination of Current Attainment of the 1-Hour...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-12

    .... 2004); and Our Children's Earth Foundation v. EPA, No. 04-73032 (9th Cir. June 28, 2005) (memorandum... attaining the revoked 1-hour ozone standard since 2008. EPA's determination that the area has attained the 1... inspection during normal business hours at the Air Protection Division, U.S. Environmental Protection...

  1. 78 FR 34964 - Implementation of the 2008 National Ambient Air Quality Standards for Ozone: State Implementation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-11

    ... for Ozone: State Implementation Plan Requirements AGENCY: Environmental Protection Agency (EPA... proposed rule ``Implementation of the 2008 National Ambient Air Quality Standards for Ozone: State... proposed rulemaking proposes to implement the 2008 ozone national ambient air quality standards...

  2. 2008 Ozone National Ambient Air Quality Standards (NAAQS) Infrastructure Actions

    EPA Pesticide Factsheets

    Read about the EPA's infrastructure actions for the 2008 Ozone NAAQS. These actions are regarding states' failure to submit SIPs addressing various parts of the standards. Here you can read the federal register notices, fact sheets, and the docket folder.

  3. 77 FR 8197 - Implementation of the 2008 National Ambient Air Quality Standards for Ozone: Nonattainment Area...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-14

    ... 1997 Ozone Standards for Transportation Conformity Purposes AGENCY: Environmental Protection Agency... designations for the 2008 ozone NAAQS for transportation conformity purposes only. DATES: Comments must be... NAAQS D. Transportation Conformity and the 1997 Ozone NAAQS III. What are the proposed...

  4. 40 CFR 50.15 - National primary and secondary ambient air quality standards for ozone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... air quality standards for ozone. 50.15 Section 50.15 Protection of Environment ENVIRONMENTAL....15 National primary and secondary ambient air quality standards for ozone. (a) The level of the national 8-hour primary and secondary ambient air quality standards for ozone (O3) is 0.075 parts...

  5. 40 CFR 50.15 - National primary and secondary ambient air quality standards for ozone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... air quality standards for ozone. 50.15 Section 50.15 Protection of Environment ENVIRONMENTAL....15 National primary and secondary ambient air quality standards for ozone. (a) The level of the national 8-hour primary and secondary ambient air quality standards for ozone (O3) is 0.075 parts...

  6. 40 CFR 50.15 - National primary and secondary ambient air quality standards for ozone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... air quality standards for ozone. 50.15 Section 50.15 Protection of Environment ENVIRONMENTAL....15 National primary and secondary ambient air quality standards for ozone. (a) The level of the national 8-hour primary and secondary ambient air quality standards for ozone (O3) is 0.075 parts...

  7. 40 CFR 50.15 - National primary and secondary ambient air quality standards for ozone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... air quality standards for ozone. 50.15 Section 50.15 Protection of Environment ENVIRONMENTAL....15 National primary and secondary ambient air quality standards for ozone. (a) The level of the national 8-hour primary and secondary ambient air quality standards for ozone (O3) is 0.075 parts...

  8. 40 CFR 50.15 - National primary and secondary ambient air quality standards for ozone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... air quality standards for ozone. 50.15 Section 50.15 Protection of Environment ENVIRONMENTAL....15 National primary and secondary ambient air quality standards for ozone. (a) The level of the national 8-hour primary and secondary ambient air quality standards for ozone (O3) is 0.075 parts...

  9. Overview of ozone human exposure and health risk analyses used in the U.S. EPA's review of the ozone air quality standard.

    SciTech Connect

    Whitfield, R. G.

    1999-03-04

    This paper presents an overview of the ozone human exposure and health risk analyses developed under sponsorship of the U.S. Environmental Protection Agency (EPA). These analyses are being used in the current review of the national ambient air quality standards (NAAQS) for ozone. The analyses consist of three principal steps: (1) estimating short-term ozone exposure for particular populations (exposure model); (2) estimating population response to exposures or concentrations (exposure-response or concentration-response models); and (3) integrating concentrations or exposure with concentration-response or exposure-response models to produce overall risk estimates (risk model). The exposure model, called the probabilistic NAAQS exposure model for ozone (pNEM/03), incorporates the following factors: hourly ambient ozone concentrations; spatial distribution of concentrations; ventilation state of individuals at time of exposure; and movement of people through various microenvironments (e.g., outdoors, indoors, inside a vehicle) of varying air quality. Exposure estimates are represented by probability distributions. Exposure-response relationships have been developed for several respiratory symptom and lung function health effects, based on the results of controlled human exposure studies. These relationships also are probabilistic and reflect uncertainties associated with sample size and variability of response among subjects. The analyses also provide estimates of excess hospital admissions in the New York City area based on results from an epidemiology study. Overall risk results for selected health endpoints and recently analyzed air quality scenarios associated with alternative 8-hour NAAQS and the current 1-hour standard for outdoor children are used to illustrate application of the methodology.

  10. 77 FR 30160 - Implementation of the 2008 National Ambient Air Quality Standards for Ozone: Nonattainment Area...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-21

    ... 1997 Ozone Standards for Transportation Conformity Purposes AGENCY: Environmental Protection Agency... provides for the revocation of the 1997 ozone NAAQS for transportation conformity purposes to occur 1 year... Received C. Final Action VI. When is the EPA revoking the 1997 ozone NAAQS for transportation...

  11. 78 FR 44485 - Implementation of the 2008 National Ambient Air Quality Standards for Ozone: State Implementation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-24

    ... for Ozone: State Implementation Plan Requirements AGENCY: Environmental Protection Agency (EPA... Standards for Ozone: State Implementation Plan Requirements'' (June 6, 2013). The EPA is extending the...) and nitrogen oxides (NO X )) that contribute to ground-level ozone formation. B. What should...

  12. Development of KRISS standard reference photometer (SRP) for ambient ozone measurement

    NASA Astrophysics Data System (ADS)

    Lee, S.; Lee, J.

    2014-12-01

    Surface ozone has adverse impacts on human health and ecosystem. Accurate measurement of ambient ozone concentration is essential for developing effective mitigation strategies and understanding atmospheric chemistry. Korea Research Institute of Standards and Science (KRISS) has developed new ozone standard reference photometers (SRPs) for the calibration of ambient ozone instruments. The basic principle of the KRISS ozone SRPs is to determine the absorption of ultraviolet radiation at a specific wavelength, 253.7 nm, by ozone in the atmosphere. Ozone concentration is calculated by converting UV transmittance through the Beer-Lambert Law. This study introduces the newly developed ozone SRPs and characterizes their performance through uncertainty analysis and comparison with BIPM (International Bureau of Weights and Measures) SRP.

  13. 77 FR 30087 - Air Quality Designations for the 2008 Ozone National Ambient Air Quality Standards

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-21

    ... 21, 2012 Part III Environmental Protection Agency 40 CFR Parts 50, 51 and 81 Air Quality Designations for the 2008 Ozone National Ambient Air Quality Standards; Implementation of the 2008 National Ambient Air Quality Standards for Ozone: Nonattainment Area Classifications Approach, Attainment Deadlines...

  14. Geostatistics as a validation tool for setting ozone standards for durum wheat.

    PubMed

    De Marco, Alessandra; Screpanti, Augusto; Paoletti, Elena

    2010-02-01

    Which is the best standard for protecting plants from ozone? To answer this question, we must validate the standards by testing biological responses vs. ambient data in the field. A validation is missing for European and USA standards, because the networks for ozone, meteorology and plant responses are spatially independent. We proposed geostatistics as validation tool, and used durum wheat in central Italy as a test. The standards summarized ozone impact on yield better than hourly averages. Although USA criteria explained ozone-induced yield losses better than European criteria, USA legal level (75 ppb) protected only 39% of sites. European exposure-based standards protected > or =90%. Reducing the USA level to the Canadian 65 ppb or using W126 protected 91% and 97%, respectively. For a no-threshold accumulated stomatal flux, 22 mmol m(-2) was suggested to protect 97% of sites. In a multiple regression, precipitation explained 22% and ozone explained <0.9% of yield variability.

  15. Regulatory Impact Analysis of the Final Revisions to the National Ambient Air Quality Standards for Ground-Level Ozone

    EPA Pesticide Factsheets

    The EPA performed an illustrative analysis of the potential costs, human health benefits, and welfare benefits of nationally attaining a revised primary ozone standard of 70 ppb and a primary alternative ozone standard level of 65 ppb.

  16. 40 CFR 50.10 - National 8-hour primary and secondary ambient air quality standards for ozone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... ambient air quality standards for ozone. 50.10 Section 50.10 Protection of Environment ENVIRONMENTAL....10 National 8-hour primary and secondary ambient air quality standards for ozone. (a) The level of the national 8-hour primary and secondary ambient air quality standards for ozone, measured by...

  17. 40 CFR Appendix P to Part 50 - Interpretation of the Primary and Secondary National Ambient Air Quality Standards for Ozone

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Secondary National Ambient Air Quality Standards for Ozone P Appendix P to Part 50 Protection of Environment... Air Quality Standards for Ozone 1. General (a) This appendix explains the data handling conventions... air quality standards for ozone (O3) specified in § 50.15 are met at an ambient O3 air...

  18. 75 FR 1566 - Public Hearings for Reconsideration of the 2008 National Ambient Air Quality Standards for Ozone

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-12

    ... Ambient Air Quality Standards for Ozone AGENCY: Environmental Protection Agency (EPA). ACTION... proposed rule, ``Reconsideration of the 2008 National Ambient Air Quality Standards for Ozone,'' which was... the following Web site: http://www.epa.gov/ttn/naaqs/standards/ozone/s_o3_cr_fr.html for the...

  19. 40 CFR 50.10 - National 8-hour primary and secondary ambient air quality standards for ozone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... ambient air quality standards for ozone. 50.10 Section 50.10 Protection of Environment ENVIRONMENTAL....10 National 8-hour primary and secondary ambient air quality standards for ozone. (a) The level of the national 8-hour primary and secondary ambient air quality standards for ozone, measured by...

  20. 40 CFR Appendix P to Part 50 - Interpretation of the Primary and Secondary National Ambient Air Quality Standards for Ozone

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Secondary National Ambient Air Quality Standards for Ozone P Appendix P to Part 50 Protection of Environment... Air Quality Standards for Ozone 1. General (a) This appendix explains the data handling conventions... air quality standards for ozone (O3) specified in § 50.15 are met at an ambient O3 air...

  1. 40 CFR 50.10 - National 8-hour primary and secondary ambient air quality standards for ozone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... ambient air quality standards for ozone. 50.10 Section 50.10 Protection of Environment ENVIRONMENTAL....10 National 8-hour primary and secondary ambient air quality standards for ozone. (a) The level of the national 8-hour primary and secondary ambient air quality standards for ozone, measured by...

  2. 40 CFR 50.10 - National 8-hour primary and secondary ambient air quality standards for ozone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... ambient air quality standards for ozone. 50.10 Section 50.10 Protection of Environment ENVIRONMENTAL....10 National 8-hour primary and secondary ambient air quality standards for ozone. (a) The level of the national 8-hour primary and secondary ambient air quality standards for ozone, measured by...

  3. 40 CFR Appendix P to Part 50 - Interpretation of the Primary and Secondary National Ambient Air Quality Standards for Ozone

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Secondary National Ambient Air Quality Standards for Ozone P Appendix P to Part 50 Protection of Environment... Air Quality Standards for Ozone 1. General (a) This appendix explains the data handling conventions... air quality standards for ozone (O3) specified in § 50.15 are met at an ambient O3 air...

  4. 40 CFR Appendix P to Part 50 - Interpretation of the Primary and Secondary National Ambient Air Quality Standards for Ozone

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Secondary National Ambient Air Quality Standards for Ozone P Appendix P to Part 50 Protection of Environment... Air Quality Standards for Ozone 1. General (a) This appendix explains the data handling conventions... air quality standards for ozone (O3) specified in § 50.15 are met at an ambient O3 air...

  5. 40 CFR 50.10 - National 8-hour primary and secondary ambient air quality standards for ozone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ambient air quality standards for ozone. 50.10 Section 50.10 Protection of Environment ENVIRONMENTAL....10 National 8-hour primary and secondary ambient air quality standards for ozone. (a) The level of the national 8-hour primary and secondary ambient air quality standards for ozone, measured by...

  6. 40 CFR Appendix P to Part 50 - Interpretation of the Primary and Secondary National Ambient Air Quality Standards for Ozone

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Secondary National Ambient Air Quality Standards for Ozone P Appendix P to Part 50 Protection of Environment... Air Quality Standards for Ozone 1. General (a) This appendix explains the data handling conventions... air quality standards for ozone (O3) specified in § 50.15 are met at an ambient O3 air...

  7. 2:30 PM EDT: EPA to Hold Media Call on Updated Ozone Standards

    EPA Pesticide Factsheets

    WASHINGTON- Today at 2:30 p.m. EDT, U.S. Environmental Protection Agency (EPA) Administrator Gina McCarthy will hold a press call on the updated ozone standards. Exposure to ozone can harm the respiratory system (the upper airways and lungs), aggrav

  8. 77 FR 4940 - Determination of Failure To Attain by 2005 and Determination of Current Attainment of the 1-Hour...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-02-01

    .... EPA, 375 F.3d 537(7th Cir. 2004) and Our Children's Earth Foundation v. EPA, No. 04-73032 (9thCir... monitored attainment of the 1-hour ozone NAAQS. EPA's review shows that the area has attained the 1-hour..., Associate Director, Office of Air Program Planning, Mailcode 3AP30, U.S. Environmental Protection...

  9. Ozone

    MedlinePlus

    ... reactive form of oxygen. In the upper atmosphere, ozone forms a protective layer that shields us from the sun’s ultraviolet rays. At ground level, ozone is a harmful air pollutant and a primary ...

  10. Ozone

    MedlinePlus

    Ozone is a gas. It can be good or bad, depending on where it is. "Good" ozone occurs naturally about 10 to 30 miles above ... the sun's ultraviolet rays. Part of the good ozone layer is gone. Man-made chemicals have destroyed ...

  11. 77 FR 35285 - Approval of Air Quality Implementation Plan; Arizona; Attainment Plan for 1997 8-Hour Ozone Standard

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-13

    ... Ozone Standard AGENCY: U.S. Environmental Protection Agency (EPA). ACTION: Final rule. SUMMARY: EPA is... demonstrate attainment of the 1997 8-hour ozone national ambient air quality standards (NAAQS) in the Phoenix... the SIP elements required for ozone nonattainment areas under title I, part D, subpart 1 of the...

  12. EPA Proposes to Redesignate Crittenden County, Ark., as Attaining the Ozone Standard

    EPA Pesticide Factsheets

    DALLAS - (Jan. 28, 2016) The U.S. Environmental Protection Agency (EPA) is proposing to approve the state of Arkansas' request to designate Crittenden County, Ark., as attaining the federal 2008 ozone standard. Crittenden County lies within the tri-

  13. PREDICTING THE IMPACT OF TROPOSPHERIC OZONE ON ECOLOGICAL RESOURCES FOR SETTING NATIONAL AMBIENT AIR QUALITY STANDARDS

    EPA Science Inventory

    The Clean Air Act provides for establishing National Ambient Air Quality Standards (NAAQS) to protect public welfare (including crops, forests, ecosystems, and soils) from adverrse effects of air pollutants, including tropospheric ozone. The formulation of policies is science-bas...

  14. Ozone (O3) Standards - Policy Assessments from Current Review

    EPA Pesticide Factsheets

    The policy assessment (PA) provides a transparent staff analysis of the scientific basis for alternative policy options for consideration by senior EPA management prior to rulemaking. These are the policy assessments used to develop the ozone NAAQS.

  15. 40 CFR Appendix I to Part 50 - Interpretation of the 8-Hour Primary and Secondary National Ambient Air Quality Standards for Ozone

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... and Secondary National Ambient Air Quality Standards for Ozone I Appendix I to Part 50 Protection of... Secondary National Ambient Air Quality Standards for Ozone 1. General. This appendix explains the data... secondary ambient air quality standards for ozone specified in § 50.10 are met at an ambient ozone...

  16. 40 CFR Appendix I to Part 50 - Interpretation of the 8-Hour Primary and Secondary National Ambient Air Quality Standards for Ozone

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... and Secondary National Ambient Air Quality Standards for Ozone I Appendix I to Part 50 Protection of... Secondary National Ambient Air Quality Standards for Ozone 1. General. This appendix explains the data... secondary ambient air quality standards for ozone specified in § 50.10 are met at an ambient ozone...

  17. 40 CFR Appendix I to Part 50 - Interpretation of the 8-Hour Primary and Secondary National Ambient Air Quality Standards for Ozone

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... and Secondary National Ambient Air Quality Standards for Ozone I Appendix I to Part 50 Protection of... Secondary National Ambient Air Quality Standards for Ozone 1. General. This appendix explains the data... secondary ambient air quality standards for ozone specified in § 50.10 are met at an ambient ozone...

  18. 40 CFR Appendix I to Part 50 - Interpretation of the 8-Hour Primary and Secondary National Ambient Air Quality Standards for Ozone

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... and Secondary National Ambient Air Quality Standards for Ozone I Appendix I to Part 50 Protection of... Secondary National Ambient Air Quality Standards for Ozone 1. General. This appendix explains the data... secondary ambient air quality standards for ozone specified in § 50.10 are met at an ambient ozone...

  19. 40 CFR Appendix I to Part 50 - Interpretation of the 8-Hour Primary and Secondary National Ambient Air Quality Standards for Ozone

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... and Secondary National Ambient Air Quality Standards for Ozone I Appendix I to Part 50 Protection of... Secondary National Ambient Air Quality Standards for Ozone 1. General. This appendix explains the data... secondary ambient air quality standards for ozone specified in § 50.10 are met at an ambient ozone...

  20. The path toward clean air: implementing new standards for ozone and fine particles

    SciTech Connect

    Lydia Wegman; Erika Sasser

    2005-04-01

    Many areas in the United States have air pollution that exceeds the levels allowed by the U.S. Environmental Protection Agency (EPA) under its revised National Ambient Air Quality Standards for ozone and fine particles. This article provides an overview of the steps EPA and states are taking to implement the new standards. 17 refs., 3 figs., 2 tabs.

  1. Standard Gibbs free energies of reactions of ozone with free radicals in aqueous solution: quantum-chemical calculations.

    PubMed

    Naumov, Sergej; von Sonntag, Clemens

    2011-11-01

    Free radicals are common intermediates in the chemistry of ozone in aqueous solution. Their reactions with ozone have been probed by calculating the standard Gibbs free energies of such reactions using density functional theory (Jaguar 7.6 program). O(2) reacts fast and irreversibly only with simple carbon-centered radicals. In contrast, ozone also reacts irreversibly with conjugated carbon-centered radicals such as bisallylic (hydroxycylohexadienyl) radicals, with conjugated carbon/oxygen-centered radicals such as phenoxyl radicals, and even with nitrogen- oxygen-, sulfur-, and halogen-centered radicals. In these reactions, further ozone-reactive radicals are generated. Chain reactions may destroy ozone without giving rise to products other than O(2). This may be of importance when ozonation is used in pollution control, and reactions of free radicals with ozone have to be taken into account in modeling such processes.

  2. EPA Approves Redesignation of Knoxville Area to Attainment for the 2008 8-Hour Ozone Standard

    EPA Pesticide Factsheets

    (07/13/15 - ATLANTA ) - Today, the U.S. Environmental Protection Agency announced that it is taking final action to approve the state of Tennessee's request to redesignate the Knoxville area to attainment for the 2008 8-hour ozone standard. This actio

  3. 78 FR 52893 - Implementation of the 2008 National Ambient Air Quality Standards for Ozone: State Implementation...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-27

    ... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION AGENCY 40 CFR Parts 50, 51, 70 and 71 RIN 2060-AR34 Implementation of the 2008 National Ambient Air Quality Standards for Ozone: State Implementation Plan Requirements Correction In proposed rule...

  4. An approach for evaluating the effectiveness of various ozone air quality standards for protecting trees.

    PubMed

    Hogsett, William E; Tingey, David T; Lee, E Henry; Beedlow, Peter A; Andersen, Christian P

    2008-06-01

    We demonstrate an approach for evaluating the level of protection attained using a variety of forms and levels of past, current, and proposed Air Quality Standards (AQSs). The U.S. Clean Air Act requires the establishment of ambient air quality standards to protect health and public welfare. However, determination of attainment of these standards is based on ambient pollutant concentrations rather than prevention of adverse effects. To determine if a given AQS protected against adverse effects on vegetation, hourly ozone concentrations were adjusted to create exposure levels that "just attain" a given standard. These exposures were used in combination with a physiologically-based tree growth model to account for the interactions of climate and ozone. In the evaluation, we used ozone concentrations from two 6-year time periods from the San Bernardino Mountains in California. There were clear differences in the level of vegetation protection achieved with the various AQSs. Based on modeled plant growth, the most effective standards were the California 8-hr average maximum of 70 ppb and a seasonal, cumulative, concentration-weighted index (SUM06), which if attained, resulted in annual growth reductions of 1% or less. Least effective was the 1-hr maximum of 120 ppb which resulted in a 7% annual reduction. We conclude that combining climate, exposure scenarios, and a process-based plant growth simulator was a useful approach for evaluating effectiveness of current or proposed air quality standards, or evaluating the form and/or level of a standard based on preventing adverse growth effects.

  5. Potential Interference Bias in Ozone Standard Compliance Monitoring.

    PubMed

    Leston, Alan R; Ollison, Will M; Spicer, Chester W; Satola, Jan

    2005-10-01

    The U.S. Environmental Protection Agency has established a federal reference method (FRM) for ozone (O3) and allowed for designation of federal equivalent methods (FEMs). However, the ethylene-chemiluminescence FRM for O3 has been replaced by the UV photometric FEM by most state and local monitoring agencies because of its relative ease of operation. Accumulating evidence indicates that the FEM is prone to bias under the hot, humid, and stagnant conditions conducive to high O3 formation. This bias may lead to overreporting hourly O3 concentrations by as much as 20-40 ppb. Measurement bias is caused by contamination of the O3 scrubber, a problem that is not detected by dry air calibration. An adequate wet test has not been codified, although a procedure has been proposed for agency consideration. This paper includes documentation of laboratory tests quantifying specific interferant responses, collocated ambient FRM/FEM monitoring results, and smog chamber comparisons of the FRM and FEMs with alternative scrubber designs. As the numbers of reports on monitor interferences have grown, interested parties have called for agency recognition and correction of these biases.

  6. Ozone

    SciTech Connect

    Not Available

    1988-06-01

    The author discusses the debate over whether concern about a hole in the ozone layer in Antarctic is real or science fiction. There is a growing consensus that efforts must be taken to protect the ozone layer. The issue now is not whether chlorofluorocarbons (CFCs) should be controlled and regulated but how much and how soon. The United States has urged that the production of dangerous CFCs, and any other chemicals that affect the ozone layer, be restricted immediately to current levels and that their use be reduced 95 percent over the next decade. The American position was too strong for many European nations and the Japanese. Negotiations at an international conference on the matter broke down. The breakdown is due in part to a more acute concern for environmental matters in the United States than exists in many countries. Meanwhile CFCs are linked to another environmental problem that equally threatens the world - the Greenhouse Effect. The earth is in a natural warming period, but man could be causing it to become even warmer. The Greenhouse Effect could have a catastrophic impact on mankind, although nothing has been proven yet.

  7. A direct sensitivity approach to predict hourly ozone resulting from compliance with the National Ambient Air Quality Standard.

    PubMed

    Simon, Heather; Baker, Kirk R; Akhtar, Farhan; Napelenok, Sergey L; Possiel, Norm; Wells, Benjamin; Timin, Brian

    2013-03-05

    In setting primary ambient air quality standards, the EPA's responsibility under the law is to establish standards that protect public health. As part of the current review of the ozone National Ambient Air Quality Standard (NAAQS), the US EPA evaluated the health exposure and risks associated with ambient ozone pollution using a statistical approach to adjust recent air quality to simulate just meeting the current standard level, without specifying emission control strategies. One drawback of this purely statistical concentration rollback approach is that it does not take into account spatial and temporal heterogeneity of ozone response to emissions changes. The application of the higher-order decoupled direct method (HDDM) in the community multiscale air quality (CMAQ) model is discussed here to provide an example of a methodology that could incorporate this variability into the risk assessment analyses. Because this approach includes a full representation of the chemical production and physical transport of ozone in the atmosphere, it does not require assumed background concentrations, which have been applied to constrain estimates from past statistical techniques. The CMAQ-HDDM adjustment approach is extended to measured ozone concentrations by determining typical sensitivities at each monitor location and hour of the day based on a linear relationship between first-order sensitivities and hourly ozone values. This approach is demonstrated by modeling ozone responses for monitor locations in Detroit and Charlotte to domain-wide reductions in anthropogenic NOx and VOCs emissions. As seen in previous studies, ozone response calculated using HDDM compared well to brute-force emissions changes up to approximately a 50% reduction in emissions. A new stepwise approach is developed here to apply this method to emissions reductions beyond 50% allowing for the simulation of more stringent reductions in ozone concentrations. Compared to previous rollback methods, this

  8. 75 FR 68736 - Approval of One-Year Extension for Attaining the 1997 8-Hour Ozone Standard for the Delaware...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-09

    ... .067 42-045-0002 Delaware/Pennsylvania 2009 .065 42-091-0013 Montgomery/Pennsylvania......... 2009 .070... standard (NAAQS). This extension is based in part on air quality data recorded during the 2009 ozone season. Specifically, the Philadelphia Area's 4th highest daily 8-hour monitored ozone value during the 2009...

  9. 76 FR 33647 - Approval and Promulgation of Determination of Attainment for the 1997 8-Hour Ozone Standard...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-06-09

    ... 51.918, a final determination that the area has met the 1997 8-hour ozone standard suspends the state... nonattainment area has attained the 1997 8-hour ozone NAAQS. This determination, in accordance with 40 CFR 51... (MO-IL) metropolitan nonattainment area has attained the 1997 8-hour National Ambient Air...

  10. Ozone emissions from a "personal air purifier".

    PubMed

    Phillips, T J; Bloudoff, D P; Jenkins, P L; Stroud, K R

    1999-01-01

    Ozone emissions were measured above a "personal air purifier" (PAP) designed to be worn on a lapel, shirt pocket, or neck strap. The device is being marketed as a negative ion generator that purifies the air. However, it also produces ozone within the person's immediate breathing zone. In order to assess worst-case potential human exposure to ozone at the mouth and nose, we measured ozone concentrations in separate tests at 1, 3, 5, and 6 in. above each of two PAPs in a closed office. One PAP was new, and one had been used slightly for 3 months. Temperature, relative humidity, atmospheric pressure, room ozone concentration, and outdoor ozone concentration also were measured concurrently during the tests. Average ozone levels measured directly above the individual PAPs ranged from 65-71 ppb at 6 in. above the device to 268-389 ppb at 1 in. above the device. Ozone emission rates from the PAPs were estimated to be 1.7-1.9 microg/minute. When house dust was sprinkled on the top grid of the PAPs, one showed an initial peak of 522 ppb ozone at 1 in., and then returned to the 200-400 ppb range. Room ozone levels increased by only 0-5 ppb during the tests. Even when two PAPs were left operating over a weekend, room ozone levels did not noticeably increase beyond background room ozone levels. These results indicate that this "PAP," even without significant background ozone, can potentially elevate the user's exposures to ozone levels greater than the health-based air quality standards for outdoor air in California (0.09 ppm, 1-hour average) and the United States (0.08 ppm, 8-hour average).

  11. Ozone Basics

    EPA Pesticide Factsheets

    Learn the difference between good (stratospheric) and bad (tropospheric) ozone, how bad ozone affects our air quality, health, and environment, and what EPA is doing about it through regulations and standards.

  12. PREDICTING THE IMPACT OF TROPOSPHERIC OZONE ON PLANTS AND ECOSYSTEMS AS A BASIS FOR SETTING NATIONAL AIR QUALITY STANDARDS

    EPA Science Inventory

    The Clean Air Act provides for establishing National Ambient Air Quality Standards (NAAQS) to protect public welfare (including crops, forests, ecosystems, and soils) from adverse effects of air pollutants, including tropospheric ozone. The formulation of policies is science-base...

  13. EPA Strengthens Ozone Standards to Protect Public Health/Science-based standards to reduce sick days, asthma attacks, emergency room visits, greatly outweigh costs

    EPA Pesticide Factsheets

    WASHINGTON - Based on extensive scientific evidence on effects that ground-level ozone pollution, or smog, has on public health and welfare, the U.S. Environmental Protection Agency (EPA) has strengthened the National Ambient Air Quality Standards (

  14. Proposed standardized definitions for vertical resolution and uncertainty in the NDACC lidar ozone and temperature algorithms - Part 2: Ozone DIAL uncertainty budget

    NASA Astrophysics Data System (ADS)

    Leblanc, Thierry; Sica, Robert J.; van Gijsel, Joanna A. E.; Godin-Beekmann, Sophie; Haefele, Alexander; Trickl, Thomas; Payen, Guillaume; Liberti, Gianluigi

    2016-08-01

    A standardized approach for the definition, propagation, and reporting of uncertainty in the ozone differential absorption lidar data products contributing to the Network for the Detection for Atmospheric Composition Change (NDACC) database is proposed. One essential aspect of the proposed approach is the propagation in parallel of all independent uncertainty components through the data processing chain before they are combined together to form the ozone combined standard uncertainty. The independent uncertainty components contributing to the overall budget include random noise associated with signal detection, uncertainty due to saturation correction, background noise extraction, the absorption cross sections of O3, NO2, SO2, and O2, the molecular extinction cross sections, and the number densities of the air, NO2, and SO2. The expression of the individual uncertainty components and their step-by-step propagation through the ozone differential absorption lidar (DIAL) processing chain are thoroughly estimated. All sources of uncertainty except detection noise imply correlated terms in the vertical dimension, which requires knowledge of the covariance matrix when the lidar signal is vertically filtered. In addition, the covariance terms must be taken into account if the same detection hardware is shared by the lidar receiver channels at the absorbed and non-absorbed wavelengths. The ozone uncertainty budget is presented as much as possible in a generic form (i.e., as a function of instrument performance and wavelength) so that all NDACC ozone DIAL investigators across the network can estimate, for their own instrument and in a straightforward manner, the expected impact of each reviewed uncertainty component. In addition, two actual examples of full uncertainty budget are provided, using nighttime measurements from the tropospheric ozone DIAL located at the Jet Propulsion Laboratory (JPL) Table Mountain Facility, California, and nighttime measurements from the JPL

  15. 40 CFR 52.977 - Control strategy and regulations: Ozone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 3 2012-07-01 2012-07-01 false Control strategy and regulations: Ozone... and regulations: Ozone. (a) Determination of Attainment. Effective March 12, 2010 EPA has determined the Baton Rouge 1-hour ozone nonattainment area has attained the 1-hour ozone National Ambient...

  16. 40 CFR 52.282 - Control strategy and regulations: Ozone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 3 2014-07-01 2014-07-01 false Control strategy and regulations: Ozone... and regulations: Ozone. (a) Attainment determination. EPA has determined that the Ventura County severe 1-hour ozone nonattainment area attained the 1-hour ozone NAAQS by the applicable attainment...

  17. 40 CFR 52.977 - Control strategy and regulations: Ozone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy and regulations: Ozone... and regulations: Ozone. Determination of Attainment. Effective March 12, 2010 EPA has determined the Baton Rouge 1-hour ozone nonattainment area has attained the 1-hour ozone National Ambient Air...

  18. 40 CFR 52.977 - Control strategy and regulations: Ozone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 3 2013-07-01 2013-07-01 false Control strategy and regulations: Ozone... and regulations: Ozone. (a) Determination of Attainment. Effective March 12, 2010 EPA has determined the Baton Rouge 1-hour ozone nonattainment area has attained the 1-hour ozone National Ambient...

  19. 40 CFR 52.282 - Control strategy and regulations: Ozone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 3 2012-07-01 2012-07-01 false Control strategy and regulations: Ozone... and regulations: Ozone. (a) Attainment determination. EPA has determined that the Ventura County severe 1-hour ozone nonattainment area attained the 1-hour ozone NAAQS by the applicable attainment...

  20. 40 CFR 52.977 - Control strategy and regulations: Ozone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 3 2011-07-01 2011-07-01 false Control strategy and regulations: Ozone... and regulations: Ozone. (a) Determination of Attainment. Effective March 12, 2010 EPA has determined the Baton Rouge 1-hour ozone nonattainment area has attained the 1-hour ozone National Ambient...

  1. 40 CFR 52.282 - Control strategy and regulations: Ozone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy and regulations: Ozone... and regulations: Ozone. (a) Attainment determination. EPA has determined that the Ventura County severe 1-hour ozone nonattainment area attained the 1-hour ozone NAAQS by the applicable attainment...

  2. 40 CFR 52.282 - Control strategy and regulations: Ozone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 3 2013-07-01 2013-07-01 false Control strategy and regulations: Ozone... and regulations: Ozone. (a) Attainment determination. EPA has determined that the Ventura County severe 1-hour ozone nonattainment area attained the 1-hour ozone NAAQS by the applicable attainment...

  3. 40 CFR 52.977 - Control strategy and regulations: Ozone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 3 2014-07-01 2014-07-01 false Control strategy and regulations: Ozone... and regulations: Ozone. (a) Determination of Attainment. Effective March 12, 2010 EPA has determined the Baton Rouge 1-hour ozone nonattainment area has attained the 1-hour ozone National Ambient...

  4. 40 CFR 52.282 - Control strategy and regulations: Ozone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 3 2011-07-01 2011-07-01 false Control strategy and regulations: Ozone... and regulations: Ozone. (a) Attainment determination. EPA has determined that the Ventura County severe 1-hour ozone nonattainment area attained the 1-hour ozone NAAQS by the applicable attainment...

  5. A Direct sensitivity approach to predict hourly ozone resulting from compliance with the National Ambient Air Quality Standard

    EPA Science Inventory

    In setting primary ambient air quality standards, the EPA’s responsibility under the law is to establish standards that protect public health. As part of the current review of the ozone National Ambient Air Quality Standard (NAAQS), the US EPA evaluated the health exposure and ...

  6. Does one size fit all? The suitability of standard ozone exposure metric conversion ratios and implications for epidemiology.

    PubMed

    Anderson, G Brooke; Bell, Michelle L

    2010-01-01

    Several exposure metrics have been applied in health research and policy settings to represent ozone exposure, such as the 24 h average and daily 8 h maximum. Frequently, results calculated using one exposure metric are converted using a simple ratio to compare or combine findings with results using a different metric. This conversion, however, assumes that such a ratio is constant across locations and time periods. We investigated the appropriateness of this conversion method by examining the relationships among various forms of ozone concentrations (24 h average, daily 1 h maximum, and daily 8 h maximum) within and between communities for 78 US communities from 2000 to 2004 and compared results to commonly used conversion ratios. We explored whether the relationships between ozone exposure metrics differ by region, weather, season, and city-specific characteristics. Analysis revealed variation in the relationship among ozone metrics, both across communities and across time within individual communities, indicating that conversion of ozone exposure metrics with a standard ratio introduces uncertainty. For example, the average ratio of the daily 8 h maximum to the daily concentration ranged from 1.23 to 1.83. Within a community, days with higher ozone levels had lower ratios. Relationships among metrics within a community were associated with daily temperature. The community-average exposure metric ratios were lower for communities with higher long-term ozone levels. Ozone metric ratios differed by season because of the different rate of change of ozone metrics throughout the year. We recommend that health effects studies present results from multiple ozone exposure metrics, if possible. When conversions are necessary, more accurate estimates can be obtained using summaries of data for a given location and time period if available, or by basing conversion ratios on data from a similar city and season, such as the results provided in this study.

  7. Long-term changes in the total ozone mapping spectrometer relative to world primary standard Dobson spectrometer 83

    SciTech Connect

    McPeters, R.D. ); Komhyr, W.D. )

    1991-02-20

    The authors have examined the stability of the calibration of the Nimbus 7 solar backscatter ultraviolet (SBUV) and total ozone mapping spectrometer (TOMS) instruments by comparing their ozone measurements with those made by a single, very stable Dobson instrument: the world primary standard Dobson spectrometer number 83. Measurements of ozone made with instrument 83 at Mauna Loa observatory in eight summers between 1979 and 1989 were compared with coincident TOMS ozone measurements. The comparison shows that relative to instrument 83, ozone measured by TOMS (and SBUV) was stable between 1979 and approximately 1983, had decreased by 3% by 1986, and had decreased by almost 7% by 1989. A similar time dependence is seen when data from an ensemble of 39 Dobson stations throughout the world is compared with TOMS over the period 1979-1987. The most likely reason for the relative drift is that the diffuser plate used by both SBUV and TOMS to measure solar flux has suffered an uncorrected wavelength dependent degradation, with most of the degradation occurring after 1983. The recently released version 6 TOMS data, corrected using the internal pair justification technique, show almost no drift relative to Dobson instrument 83. The authors conclude from these comparisons that accurate measurements of long-term global ozone change will require a coherent system incorporating both ground based and satellite based ozone measurements.

  8. Important considerations for establishing a secondary ozone standard to protect vegetation

    SciTech Connect

    Lefohn, A.S. ); Runeckles, V.C. ); Krupa, S.V. ); Shadwick, D.S. )

    1989-08-01

    Based on recent evidence published in the literature, as well as retrospective studies using data from the National Crop Loss Assessment Network (NCLAN), cumulative indices can be used to describe exposures of ozone for predicting agricultural crop effects. However, the mathematical form of the standard that may be proposed to protect crops does not necessarily have to be of the same form as that used in the statistical or process oriented mathematical models that relate ambient ozone exposures with vegetation effects. This paper discusses the limitations associated with applying a simple statistic that may take the place of a more biologically meaningful exposure parameter. While the NCLAN data have been helpful in identifying identifying indices that may be appropriate for establishing exposure-response relationships, the limitations associated with the NCLAN protocol need to be considered when attempting to apply these relationships in the establishment of a secondary national ambient air quality standard. The Weibull model derived from NCLAN experiments must demonstrate its generality and universal applicability. Furthermore, its predictive power must be tested using independent sets of field data.

  9. Are the elements of the proposed ozone National Ambient Air Quality Standards informed by the best available science?

    PubMed

    Goodman, Julie E; Sax, Sonja N; Lange, Sabine; Rhomberg, Lorenz R

    2015-06-01

    The United States Environmental Protection Agency (US EPA) issues National Ambient Air Quality Standards (NAAQS) for six criteria pollutants, including ozone. Each standard has four elements: an indicator, level, averaging time, and form. Ozone levels (i.e., air concentrations) alone in scientific studies are not directly comparable to the "level" element of the NAAQS because the standard considers the level in the context of its relation to the remaining elements. Failure to appreciate this has led to misunderstandings regarding NAAQS that would be health-protective. This can be seen with controlled human ozone exposure studies, which often involved small numbers of people exercising quasi-continuously for a long duration at an intensity not common in the general population (and unlikely achievable by most sensitive individuals), under worst-case exposure profiles. In addition, epidemiology studies have used different averaging times and have had methodological limitations that may have biased results. Such considerations can make it difficult to compare ozone levels and results across studies and to appropriately apply them in a NAAQS evaluation. Relating patterns and circumstances of exposure, and exposure measurements, to all elements of the NAAQS can be challenging, but if US EPA fully undertook this, it would be evident that available evidence does not indicate that proposed lower ozone standards would be more health protective than the current one.

  10. 2008 Ozone National Ambient Air Quality Standards (NAAQS) Findings of Failure to Submit

    EPA Pesticide Factsheets

    This final action finds that 15 states and the District of Columbia have failed to submit specific state implementation plan (SIP) elements to satisfy certain nonattainment area, and/or Ozone Transport Region (OTR), planning requirements for the 2008 ozone

  11. 2015 Revision to 2008 Ozone National Ambient Air Quality Standards (NAAQS) Supporting Documents

    EPA Pesticide Factsheets

    Find tools for background ozone, maps of nonattainment areas, an overview of the proposal, and information on designations, monitoring and permitting requirements and a presentation on the 2015 ozone NAAQS revision.

  12. 2014 Proposed Revision to 2008 Ozone National Ambient Air Quality Standards (NAAQS) Supporting Documents

    EPA Pesticide Factsheets

    Find information on the 2014 proposed ozone NAAQS revision, and find tools for background ozone, maps of nonattainment areas, an overview of the proposal, and information on designations, monitoring and permitting requirements

  13. Estimating potential productivity cobenefits for crops and trees from reduced ozone with U.S. coal power plant carbon standards

    NASA Astrophysics Data System (ADS)

    Capps, Shannon L.; Driscoll, Charles T.; Fakhraei, Habibollah; Templer, Pamela H.; Craig, Kenneth J.; Milford, Jana B.; Lambert, Kathleen F.

    2016-12-01

    A standard for carbon dioxide emissions from power plants in the United States, known as the Clean Power Plan, has been finalized by the Environmental Protection Agency. Decreases in carbon dioxide emissions from fossil fuel combustion have the potential cobenefit of reductions in emissions of oxides of nitrogen, which contribute to the formation of ground-level ozone. Emissions of ozone precursors may result in elevated ozone concentrations nearby or downwind. Chronic exposure of sensitive vegetation to tropospheric ozone reduces its potential productivity. To evaluate the cobenefits of the Clean Power Plan to sensitive vegetation, we estimate ozone concentrations in the continental U.S. in 2020 with a chemical transport model in accordance with reference and alternative Clean Power Plan policy scenarios, which represent a range of possible approaches to reducing carbon dioxide emissions from power plants. The reductions in biomass, or the potential productivity losses, due to the exposure of 4 crops and 11 tree species to ozone are as large as 1.9% and 32%, respectively, in the reference scenario. The least stringent policy scenario reduces these losses by less than 3% for any given species; however, the scenarios consistent with policies resulting in more rigorous nitrogen oxide reductions produce potential productivity losses lower than the reference scenario by as much as 16% and 13% for individual crops or tree species, respectively. This analysis affords the opportunity to consider public welfare cobenefits of a regulation that is designed to reduce carbon dioxide emissions from power plants.

  14. OZONE TOXICOLOGY: HISTORICAL PERSPECTIVES OF HTE SCIENCE THAT SHAPED THE REGULATORY STANDARDS

    EPA Science Inventory

    Ozone can be found in essentially all locations in the troposphere. Too much exposure of vegetation and humans to this potent oxidizing gas can prove toxic. Reports of human toxicity to ozone first appeared in the 1800's from accidental occupational exposures when ozone was fir...

  15. Using the World Primary Standard Dobson Spectrometer to Monitor the Stability of a Multi-Instrument Satellite Ozone Dataset

    NASA Technical Reports Server (NTRS)

    McPeters, R.D.; Oltmans, Samuel J.

    2000-01-01

    NASA is creating a long term satellite ozone time series by combining data from multiple instruments: Nimbus 7 Total Ozone Mapping Spectrometer (TOMS) (1978 - 1993), Meteor 3 TOMS (1991 - 1994), Earth Probe TOMS (1996 - present), Nimbus 7 SB-JV (1978 - 1990), NOAA-9 Solar Backscatter UV Spectrometer (SBUV/2) (1984 - 1997), NOAA-11 SBUV/2 (1989 - 1994), and NOAA-14 SBUV/2 (1995 - present). The stability of individual data sets and possible instrument-to-instrument differences are best checked by comparison with ground-based measurements. We have examined the time dependence of the calibrations of these instruments by comparing satellite derived ozone with that measured by the world primary standard Dobson spectrometer No. 83. This instrument has been maintained since 1962 as a standard for total ozone to an uncertainty of plus or minus 0.5%. Measurements of AD pair ozone made with instrument No. 83 at Mauna Loa observatory most summers since 1979 were compared with coincident TOMS and SBUV(/2) ozone measurements. The comparison shows that the various instruments were stable relative to instrument No. 83 to within about plus or minus 1%, but that there are instrument-to-instrument biases of as much as 3%. Earth Probe TOMS, for example, is 1% to 2% high relative to Nimbus 7 TOMS when the world standard instrument is used as a transfer standard. Similar results are seen when comparisons are made with an ensemble of 41 Dobson stations throughout the world, demonstrating that the ensemble as a whole is stable despite the fact that many instruments within the ensemble have clear calibration changes.

  16. Comparison of UV/ozone cleaning of platinum/iridium kilogram mass standards with nettoyage-lavage cleaning

    NASA Astrophysics Data System (ADS)

    Berry, James; Davidson, Stuart; Barat, Pauline; Davis, Richard

    2011-06-01

    A cleaning method using ultraviolet activated ozone has been developed at the National Physical Laboratory (NPL). A comparison to test the effectiveness of this cleaning method with nettoyage-lavage cleaning on platinum-iridium artefacts and kilogram mass standards was undertaken at the Bureau International des Poids et Mesures (BIPM). Three cleaning trials were performed to compare the effectiveness of the two methods at removing natural, medium and heavy levels of surface contamination. Both the ultraviolet light/ozone method and the nettoyage-lavage method successfully removed both natural levels and medium levels of surface contamination. However, in the medium contamination trial nettoyage-lavage cleaning removed additional mass from the Pt/Ir mass standard under test that could not be accounted for in terms of surface contamination. In the heavy contamination trial nettoyage-lavage cleaning successfully removed most of the contamination from the surface of the contaminated Pt/Ir mass standard. The ultraviolet light/ozone method removed about two thirds of the surface contamination and therefore for heavily contaminated mass standards it is advisable to pre-clean them with a solvent before ultraviolet/ozone cleaning.

  17. Effects of light duty gasoline vehicle emission standards in the United States on ozone and particulate matter

    NASA Astrophysics Data System (ADS)

    Vijayaraghavan, Krish; Lindhjem, Chris; DenBleyker, Allison; Nopmongcol, Uarporn; Grant, John; Tai, Edward; Yarwood, Greg

    2012-12-01

    More stringent motor vehicle emission standards are being considered in the United States to attain national air quality standards for ozone and PM2.5. We modeled past, present and potential future US emission standards for on-road gasoline-fueled light duty vehicles (including both cars and light trucks) (LDVs) to assess incremental air quality benefits in the eastern US in 2022. The modeling results show that large benefits in ozone and PM2.5 (up to 16 ppb (14%) reductions in daily maximum 8-h ozone, up to 10 ppb (11%) reductions in the monthly mean of daily maximum 8-h ozone, up to 4.5 μg m-3 (9%) reductions in maximum 24-h PM2.5 and up to 2.1 μg m-3 (10%) reductions in the monthly mean PM2.5) accrued from the transition from Tier 1 to Tier 2 standards. However, the implementation of additional nationwide LDV controls similar to draft proposed California LEV III regulations would result in very small additional improvements in air quality by 2022 (up to 0.3 ppb (0.3%) reductions in daily maximum 8-h ozone, up to 0.2 ppb (0.2%) reductions in the monthly mean of daily maximum 8-h ozone, up to 0.1 μg m-3 (0.5%) reductions in maximum 24-h PM2.5 and up to 0.1 μg m-3 (0.5%) reductions in the monthly mean PM2.5). The complete elimination of gasoline-fueled LDV emissions in 2022 is predicted to result in improvements in air quality (up to 7 ppb (8%) reductions in daily maximum 8-h ozone, up to 4 ppb (6%) reductions in the monthly mean of daily maximum 8-h ozone, up to 2.8 μg m-3 (7%) reductions in maximum 24-h PM2.5 and up to 1.8 μg m-3 (8%) reductions in the monthly mean PM2.5) from Tier 2 levels, that are generally smaller than the improvements obtained in switching from Tier 1 to Tier 2.

  18. Ozone (O3) Standards - Other Technical Documents from the Current Review

    EPA Pesticide Factsheets

    These memoranda were each sent in to the Ozone NAAQS Review Docket, EPA-HQ-OAR-2008-0699, after the proposed rule was published. They present technical data on the methods, monitoring stations, and metrics used to estimate ozone concentrations.

  19. Fact Sheets on Review of National Ambient Air Quality Standards for Ozone Staff Papers

    EPA Pesticide Factsheets

    The second draft Staff Paper points to an expanded body of health effects evidence suggesting a wide range of adverse health effects associated with exposure to ambient ozone. This is part of the process for review of the NAAQS for ground-level ozone.

  20. Emission reductions and urban ozone responses under more stringent US standards

    NASA Astrophysics Data System (ADS)

    Downey, Nicole; Emery, Chris; Jung, Jaegun; Sakulyanontvittaya, Tanarit; Hebert, Laura; Blewitt, Doug; Yarwood, Greg

    2015-01-01

    We use a photochemical grid model instrumented with the high-order Decoupled Direct Method (HDDM) to evaluate the response of ozone (O3) to reductions in US-wide anthropogenic emissions, and to estimate emission reductions necessary to meet more stringent National Ambient Air Quality Standards (NAAQS) for O3. We simulate hourly O3 response to nationwide reductions in nitrogen oxides (NOx) and volatile organic compound (VOC) emissions throughout 2006 and compare O3 responses in 4 US cities: Los Angeles, Sacramento, St. Louis, and Philadelphia. We compare O3 responses between NOx-rich, O3-inhibited urban core sites and NOx-sensitive, higher O3 suburban sites and analyze projected O3 frequency distributions, which can be used to drive health effect models. We find that 2006 anthropogenic NOx and VOC emissions must be reduced by 60-70% to reach annual 4th highest (H4) maximum daily 8-h (MDA8) O3 of 75 ppb (the current US standard) in Sacramento, St. Louis, and Philadelphia, and by 80-85% to reach an H4 MDA8 of 60 ppb. Los Angeles requires larger emissions reductions and achieves an H4 MDA8 of 75 ppb with 92% reductions and 60 ppb with 97% reductions. As emissions are reduced, hourly and MDA8 frequency distributions tend toward mid-level background distributions. Mid-level O3 exposure is an important driver of O3 health impacts calculated by epidemiological models. A significant fraction (at least 48%) of summertime integrated MDA8 O3 at all sites remains after complete elimination of US anthropogenic NOx and VOC emissions, implying that mid-level O3 exposure due to background will become more important as domestic precursor emissions are controlled.

  1. Role of Concentration and Time of Day in Developing Ozone Exposure Indices for a Secondary Standard.

    PubMed

    Lee, E H; Hogsett, W E

    1999-06-01

    Evidence from exposure-response studies and a turbulent transfer model demonstrate that plant response is differential to concentration, duration, temporal pattern, and time of day of exposure. Reductions in productivity of crops and trees as seedlings are greater when plants are exposed to higher daytime ozone (O3) concentrations (0800-2000 hr standard time) or for longer durations. Primary evidence on the greater role of concentration comes from exposure-response experiments where plants are exposed to a series of pollutant concentrations in open-top chambers under field conditions. These studies demonstrate that the integrated exposure indices that give preferential weight to higher concentrations are better predictors of response than mean or peak indices. Evidence suggesting that mid-range O3 concentrations (0.05-0.09 parts per million, ppm) play a greater role than higher concentrations (>0.09 ppm) in biological response could not be justified. The time of day when O3 concentrations and atmospheric and stomatal conductances of gas exchange are optimal is a key to understanding plant response because plants respond only to O3 entering the leaf via stomata. A turbulent transfer model that describes the resistance of pollutant gas exchange from the atmosphere to the boundary layer of a forest canopy, as a function of micrometeorological variables, is developed to determine when flux of O3 is optimal. Based on meteorological and ambient air quality monitoring data at remote forest sites in the United States, it appears that O3 flux densities to the forest boundary layer are optimal during the 0800-2000 hr window. It is concluded that descriptors of ambient air quality for use in setting a federal standard should (1) cumulate hourly O3 concentrations, (2) give preferential weight to daytime concentrations between 0800 and 2000 hr, and (3) give preferential weight to higher O3 concentrations.

  2. Ozone Pollution

    EPA Pesticide Factsheets

    Known as tropospheric or ground-level ozone, this gas is harmful to human heath and the environment. Since it forms from emissions of volatile organic compounds (VOCs) and nitrogen oxides (NOx), these pollutants are regulated under air quality standards.

  3. Ozone and plants: need for a biologically based air quality standard.

    PubMed

    Manning, William J

    2002-02-01

    For the past 10 years, I have spent parts of late July and early August in central Europe, assessing ozone injury symptom expression on native plants in upland meadows and along forest edges. Much of this work has been done with local colleagues in and near the Tatra Mountains in southern Poland and eastern Slovakia and in the Carpathian Mountains in western Ukraine. Active and passive ozone air monitors and samplers were also used at most of the study sites.

  4. Standardizing Interfaces for External Access to Data and Processing for the NASA Ozone Product Evaluation and Test Element (PEATE)

    NASA Technical Reports Server (NTRS)

    Tilmes, Curt A.; Fleig, Albert J.

    2008-01-01

    NASA's traditional science data processing systems have focused on specific missions, and providing data access, processing and services to the funded science teams of those specific missions. Recently NASA has been modifying this stance, changing the focus from Missions to Measurements. Where a specific Mission has a discrete beginning and end, the Measurement considers long term data continuity across multiple missions. Total Column Ozone, a critical measurement of atmospheric composition, has been monitored for'decades on a series of Total Ozone Mapping Spectrometer (TOMS) instruments. Some important European missions also monitor ozone, including the Global Ozone Monitoring Experiment (GOME) and SCIAMACHY. With the U.S.IEuropean cooperative launch of the Dutch Ozone Monitoring Instrument (OMI) on NASA Aura satellite, and the GOME-2 instrumental on MetOp, the ozone monitoring record has been further extended. In conjunction with the U.S. Department of Defense (DoD) and the National Oceanic and Atmospheric Administration (NOAA), NASA is now preparing to evaluate data and algorithms for the next generation Ozone Mapping and Profiler Suite (OMPS) which will launch on the National Polar-orbiting Operational Environmental Satellite System (NPOESS) Preparatory Project (NPP) in 2010. NASA is constructing the Science Data Segment (SDS) which is comprised of several elements to evaluate the various NPP data products and algorithms. The NPP SDS Ozone Product Evaluation and Test Element (PEATE) will build on the heritage of the TOMS and OM1 mission based processing systems. The overall measurement based system that will encompass these efforts is the Atmospheric Composition Processing System (ACPS). We have extended the system to include access to publically available data sets from other instruments where feasible, including non-NASA missions as appropriate. The heritage system was largely monolithic providing a very controlled processing flow from data.ingest of

  5. Setting Spacecraft Maximum Allowable Concentrations for 1 hour or 24 hour contingency exposures to airborne chemicals

    NASA Technical Reports Server (NTRS)

    Garcia, Hector D.; Limero, Thomas F.; James, John T.

    1992-01-01

    Since the early years of the manned space program, NASA has developed and used exposure limits called Spacecraft Maximum Allowable Concentrations (SMACs) to help protect astronauts from airborne toxicants. Most of these SMACS are based on an exposure duration of 7 days, since this is the duration of a 'typical' mission. A set of 'contingency SMACs' is also being developed for scenarios involving brief (1-hour or 24- hour) exposures to relatively high levels of airborne toxicants from event-related 'contingency' releases of contaminants. The emergency nature of contingency exposures dictates the use of different criteria for setting exposure limits. The NASA JSC Toxicology Group recently began a program to document the rationales used to set new SMACs and plans to review the older, 7-day SMACs. In cooperation with the National Research Council's Committee on Toxicology, a standard procedure has been developed for researching, setting, and documenting SMAC values.

  6. Intercomparison of ultraviolet photometry and gas-phase titration techniques for ozone reference standards at ambient levels

    NASA Astrophysics Data System (ADS)

    Tanimoto, Hiroshi; Mukai, Hitoshi; Hashimoto, Shigeru; Norris, James E.

    2006-08-01

    Intercomparison experiments were made between two independent techniques for ozone (O3) reference standards often used as the primary standards in air quality monitoring networks. These techniques include ultraviolet absorption photometry of O3 at the 253.7-nm Hg line and gas-phase titration of O3 with excess NO. For ultraviolet photometry, a well-designed and maintained standard reference photometer (SRP) built by the National Institute of Standards and Technology (USA) was employed. For gas-phase titration (GPT), an existing system was significantly modified by the National Institute for Environmental Studies (Japan) by using gravimetric NO/N2 standard gases, accurate flow measurement systems based on laminar flow elements, and two chemiluminescence NO detectors to minimize uncertainty in the measurements, which had previously been a major shortcoming of this method. Uncertainty in the improved GPT system was reduced to less than 0.4% above 100 nmol mol-1 O3 mole fraction. A series of comparison runs between the two methods over the course of 13 months from August 2004 to August 2005 showed a significant discrepancy, which cannot be explained by the measurement uncertainties attributed to either SRP or GPT in the range of 80-800 nmol mol-1 O3, where GPT was about 2% higher than SRP. This result indicates possible biases in the currently existing O3 reference standards and warrants further studies to identify and characterize possible sources of the systematic discrepancy.

  7. 77 FR 51798 - First Draft Documents Related to the Review of the National Ambient Air Quality Standards for Ozone

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-27

    ... Ozone AGENCY: Environmental Protection Agency (EPA). ACTION: Notice of extension of comment period... documents titled, Health Risk and Exposure Assessment for Ozone, First External Review Draft; Welfare Risk and Exposure Assessment for Ozone, First External Review Draft; and Policy Assessment for the...

  8. 77 FR 21690 - Approval and Promulgation of Air Quality Implementation Plan for 1997 8-Hour Ozone Standard; Arizona

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-11

    ... Ozone Nonattainment Area A. Background on the 1997 8-Hour Ozone NAAQS Ground-level ozone pollution is... by many types of pollution sources including on- and off-road motor vehicles and engines, power plants and industrial facilities, and smaller area sources such as lawn and garden equipment and...

  9. Impacts of extra-regional pollutants on summertime California ozone levels and the implications on the secondary ozone standard design values

    NASA Astrophysics Data System (ADS)

    Huang, M.; Carmichael, G. R.; Kulkarni, S.; Spak, S.; Chai, T.; Pierce, R.

    2011-12-01

    Transported ozone (O3) from outside of the North America (NA) as well as the lower stratospheric O3 (referred to as extra-regional O3 in this paper), together with the locally-formed O3 from anthropogenic and natural emissions, affect the O3 variability over California. Quantification of the contributions from these sources is important as it helps define national emission reductions strategies. The impact of extra-regional anthropogenic and fire sources on California surface air quality during summer 2008 is evaluated using a multi-scale STEM modeling system. Several forward sensitivity simulations are conducted to estimate the contributions of extra-regional O3 and precursors on California O3 levels, indicating the direct transport of O3 through the model boundaries is the largest single extra-regional contributor, and peroxyacetyl nitrate (PAN) plays an important role among several precursors. Weak impacts from stratospheric O3 are shown during this period. The impacts of extra-regional pollution from each of these contributing factors present regional differences over California and other western US states. The O3 sensitivity to extra-regional pollution is also compared with a sensitivity simulation with local emissions perturbed. The secondary O3 standard design value is the 3-year average of the annual maximum consecutive 3-month sum of adjusted monthly W126 index values, and is recommended to be set at a level in the range of 7 to 21 ppm-hours. Many of the areas violate the proposed secondary O3 standard without violating the primary O3 standard are located in rural areas due to long-range transport of O3 and its precursors. Here we calculate the sensitivity of monthly-based W126 index to extra-regional pollution based on the model forward sensitivity simulations. The surface O3 sensitivity to trans-boundary pollution over California is further interpreted by trajectories and adjoint sensitivity analysis. Probability of airmasses originating from northern

  10. 40 CFR 52.350 - Control strategy: Ozone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 3 2014-07-01 2014-07-01 false Control strategy: Ozone. 52.350 Section...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Colorado § 52.350 Control strategy: Ozone. (a) Revisions to the Colorado State Implementation Plan, 1-hour ozone NAAQS Redesignation Request and...

  11. 40 CFR 52.2275 - Control strategy and regulations: Ozone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 4 2011-07-01 2011-07-01 false Control strategy and regulations: Ozone... strategy and regulations: Ozone. (a) Section 510.3 of revised Regulation V, which was submitted by the..., concerning the Victoria County 1-hour ozone maintenance plan. This SIP revision was adopted by TCEQ...

  12. 40 CFR 52.350 - Control strategy: Ozone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 3 2013-07-01 2013-07-01 false Control strategy: Ozone. 52.350 Section...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Colorado § 52.350 Control strategy: Ozone. (a) Revisions to the Colorado State Implementation Plan, 1-hour ozone NAAQS Redesignation Request and...

  13. 40 CFR 52.2275 - Control strategy and regulations: Ozone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 5 2014-07-01 2014-07-01 false Control strategy and regulations: Ozone... strategy and regulations: Ozone. (a) Section 510.3 of revised Regulation V, which was submitted by the... Areas Did Not Attain the 1-Hour Ozone NAAQS. EPA has determined that the...

  14. 40 CFR 52.350 - Control strategy: Ozone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 3 2011-07-01 2011-07-01 false Control strategy: Ozone. 52.350 Section...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Colorado § 52.350 Control strategy: Ozone. (a) Revisions to the Colorado State Implementation Plan, 1-hour ozone NAAQS Redesignation Request and...

  15. 40 CFR 52.350 - Control strategy: Ozone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 3 2012-07-01 2012-07-01 false Control strategy: Ozone. 52.350 Section...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Colorado § 52.350 Control strategy: Ozone. (a) Revisions to the Colorado State Implementation Plan, 1-hour ozone NAAQS Redesignation Request and...

  16. 40 CFR 52.2275 - Control strategy and regulations: Ozone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 5 2013-07-01 2013-07-01 false Control strategy and regulations: Ozone... strategy and regulations: Ozone. (a) Section 510.3 of revised Regulation V, which was submitted by the... Areas Did Not Attain the 1-Hour Ozone NAAQS. EPA has determined that the...

  17. 40 CFR 52.2275 - Control strategy and regulations: Ozone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 5 2012-07-01 2012-07-01 false Control strategy and regulations: Ozone... strategy and regulations: Ozone. (a) Section 510.3 of revised Regulation V, which was submitted by the..., concerning the Victoria County 1-hour ozone maintenance plan. This SIP revision was adopted by TCEQ...

  18. 40 CFR 52.2275 - Control strategy and regulations: Ozone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy and regulations: Ozone... strategy and regulations: Ozone. (a) Section 510.3 of revised Regulation V, which was submitted by the..., concerning the Victoria County 1-hour ozone maintenance plan. This SIP revision was adopted by TCEQ...

  19. 40 CFR 52.350 - Control strategy: Ozone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.350 Section...) APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS Colorado § 52.350 Control strategy: Ozone. (a) Revisions to the Colorado State Implementation Plan, 1-hour ozone NAAQS Redesignation Request and...

  20. Guidance for 1-Hour Sulfur Dioxide (SO2) Nonattainment Area State Implementation Plans (SIP) Submissions

    EPA Pesticide Factsheets

    The document is intended to provide guidance and recommendations to state, local and tribal governments for the development of SIPs and tribal implementation plans (TIPs) under the 2010 1-hour primary NAAQS for Sulfur Dioxide (SO2).

  1. AN APPROACH FOR EVALUATING THE EFFECTIVENESS OF VARIOUS OZONE AIR QUALITY STANDARDS FOR PROTECTING TREES

    EPA Science Inventory

    We demonstrate an approach for evaluating the level of protection attained using a variety of forms and levels of past, current, and proposed Air Quality Standards (AQSs). The U.S. Clean Air Act requires the establishment of ambient air quality standards to protect health and pub...

  2. OZONE AMBIENT AIR QUALITY STANDARD HAS BENEFICIAL EFFECT ON PONDEROSA PINE IN CALIFORNIA

    EPA Science Inventory

    Ambient air quality standards and control strategies are implemented to protect humans and vegetation from adverse effects. However, to date there has not been a simple and objective method to determine if the standards and resultant control strategies have reduced O3 impacts on ...

  3. Direct assessment of international consistency of standards for ground-level ozone: strategy and implementation toward metrological traceability network in Asia.

    PubMed

    Tanimoto, H; Mukai, H; Sawa, Y; Matsueda, H; Yonemura, S; Wang, T; Poon, S; Wong, A; Lee, G; Jung, J Y; Kim, K R; Lee, M H; Lin, N H; Wang, J L; Ou-Yang, C F; Wu, C F; Akimoto, H; Pochanart, P; Tsuboi, K; Doi, H; Zellweger, C; Klausen, J

    2007-11-01

    An international exercise to directly assess consistency of standards for ground-level ozone in East Asia was conducted as part of the East Asian Regional Experiment 2005 (EAREX 2005) in the framework of the Atmospheric Brown Clouds (ABC) project. Ten organizations collaboratively participated in the intercomparison. Four groups representing Japan, Korea, Hong Kong, and Taiwan made comparisons at the Gosan super observatory, Jeju Island, Korea, in March 2005, with ozone instruments calibrated to their national standards, and four Japanese groups made off-site comparisons with laboratory-level standards. All comparisons generally indicated good agreement with the standard reference photometer (SRP) 35, built by the National Institute of Standards and Technology (USA) and maintained by the National Institute for Environmental Studies (Japan). The assessment was expanded to measurement networks contributing to the World Meteorological Organization's Global Atmospheric Watch (WMO/GAW) program as part of off-site comparisons, and excellent agreement was achieved. These efforts contribute to propagating traceability of the national metrology standards among the atmospheric science community, to ensuring comparability of the existing ozone measurements, and to establishing an integrated network of air quality monitoring in Asia.

  4. 75 FR 68733 - Approval and Promulgation of One-Year Extension for Attaining the 1997 8-Hour Ozone Standard for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-11-09

    .../Pennsylvania 2009 .065 42-091-0013 Montgomery/Pennsylvania......... 2009 .070 42-101-0004 Philadelphia..., quality-assured air quality data recorded during the 2009 ozone season. In accordance with requirements... the 2009 ozone season at each monitor in the area is less than 0.084 parts per million (ppm). If...

  5. 75 FR 10420 - Approval and Promulgation of Implementation Plans: 1-Hour Ozone Extreme Area Plan for San Joaquin...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-08

    ... approval/limited disapproval of SJVAPCD's Rule 4570, Confined Animal Facilities at 74 FR 33948 (July 14... ``aspirational goal.'' In addition, Earthjustice singles out El Comite Para El Bienestar de Earlimart...

  6. Standardization of the Definitions of Vertical Resolution and Uncertainty in the NDACC-archived Ozone and Temperature Lidar Measurements

    NASA Technical Reports Server (NTRS)

    Leblanc, T.; Godin-Beekmann, S.; Payen, Godin-Beekmann; Gabarrot, Franck; vanGijsel, Anne; Bandoro, J.; Sica, R.; Trickl, T.

    2012-01-01

    The international Network for the Detection of Atmospheric Composition Change (NDACC) is a global network of high-quality, remote-sensing research stations for observing and understanding the physical and chemical state of the Earth atmosphere. As part of NDACC, over 20 ground-based lidar instruments are dedicated to the long-term monitoring of atmospheric composition and to the validation of space-borne measurements of the atmosphere from environmental satellites such as Aura and ENVISAT. One caveat of large networks such as NDACC is the difficulty to archive measurement and analysis information consistently from one research group (or instrument) to another [1][2][3]. Yet the need for consistent definitions has strengthened as datasets of various origin (e.g., satellite and ground-based) are increasingly used for intercomparisons, validation, and ingested together in global assimilation systems.In the framework of the 2010 Call for Proposals by the International Space Science Institute (ISSI) located in Bern, Switzerland, a Team of lidar experts was created to address existing issues in three critical aspects of the NDACC lidar ozone and temperature data retrievals: signal filtering and the vertical filtering of the retrieved profiles, the quantification and propagation of the uncertainties, and the consistent definition and reporting of filtering and uncertainties in the NDACC- archived products. Additional experts from the satellite and global data standards communities complement the team to help address issues specific to the latter aspect.

  7. 40 CFR 51.905 - How do areas transition from the 1-hour NAAQS to the 1997 8-hour NAAQS and what are the anti...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... NAAQS to the 1997 8-hour NAAQS and what are the anti-backsliding provisions? 51.905 Section 51.905... National Ambient Air Quality Standard § 51.905 How do areas transition from the 1-hour NAAQS to the 1997 8... implement the applicable requirements as defined in § 51.900(f), except as provided in paragraph...

  8. Concentration measurements of ozone in the 1200-300ppbv range: an intercomparison between the BNM ultraviolet standard and infrared methods.

    PubMed

    Dufour, Gaëlle; Valentin, Alain; Henry, Annie; Hurtmans, Daniel; Camy-Peyret, Claude

    2004-12-01

    Simultaneous ultraviolet (UV) and infrared (IR) measurements of ozone concentration in air in the 1200-300 ppbv range have been performed using the ultraviolet absorption in the Hartley band at 0.2537 microm and the infrared absorption of a doublet at 9.507 microm in the nu(3) vibration-rotation band. Infrared concentration measurements were achieved using the tunable diode laser spectrometer of LPMA in Paris with interferometric control of the emitted wavelength while the UV concentration measurements were performed with the 49PS Megatec ozone generator of the Bureau National de Metrologie (BNM). The simultaneous recording of spectra of a reference cell filled with pure distilled ozone and of a low concentration mixture inside a long absorbing path Herriott cell allows to carry out infrared concentration measurements with an accuracy of the same order as the ultraviolet ones and provides the instrumental parameters of the spectrometer corresponding to each concentration measurement, which reduces systematic errors. Within the respective absolute uncertainties proper to the two techniques, no systematic discrepancy was evidenced between the IR and the UV measurements. The ozone ultraviolet absorption coefficient value determined by Hearn (308.3 +/- 4 cm(-1)atm(-1)) and used by the BNM and the National Institute of Standards and Technology (NIST) is confirmed by the present work.

  9. Concentration measurements of ozone in the 1200-300 ppbv range: an intercomparison between the BNM ultraviolet standard and infrared methods

    NASA Astrophysics Data System (ADS)

    Dufour, Gaëlle; Valentin, Alain; Henry, Annie; Hurtmans, Daniel; Camy-Peyret, Claude

    2004-12-01

    Simultaneous ultraviolet (UV) and infrared (IR) measurements of ozone concentration in air in the 1200-300 ppbv range have been performed using the ultraviolet absorption in the Hartley band at 0.2537 μm and the infrared absorption of a doublet at 9.507 μm in the ν3 vibration-rotation band. Infrared concentration measurements were achieved using the tunable diode laser spectrometer of LPMA in Paris with interferometric control of the emitted wavelength while the UV concentration measurements were performed with the 49PS Megatec ozone generator of the Bureau National de Métrologie (BNM). The simultaneous recording of spectra of a reference cell filled with pure distilled ozone and of a low concentration mixture inside a long absorbing path Herriott cell allows to carry out infrared concentration measurements with an accuracy of the same order as the ultraviolet ones and provides the instrumental parameters of the spectrometer corresponding to each concentration measurement, which reduces systematic errors. Within the respective absolute uncertainties proper to the two techniques, no systematic discrepancy was evidenced between the IR and the UV measurements. The ozone ultraviolet absorption coefficient value determined by Hearn (308.3±4 cm -1 atm -1) and used by the BNM and the National Institute of Standards and Technology (NIST) is confirmed by the present work.

  10. Proposed standardized definitions for vertical resolution and uncertainty in the NDACC lidar ozone and temperature algorithms - Part 1: Vertical resolution

    NASA Astrophysics Data System (ADS)

    Leblanc, Thierry; Sica, Robert J.; van Gijsel, Joanna A. E.; Godin-Beekmann, Sophie; Haefele, Alexander; Trickl, Thomas; Payen, Guillaume; Gabarrot, Frank

    2016-08-01

    A standardized approach for the definition and reporting of vertical resolution of the ozone and temperature lidar profiles contributing to the Network for the Detection for Atmospheric Composition Change (NDACC) database is proposed. Two standardized definitions homogeneously and unequivocally describing the impact of vertical filtering are recommended. The first proposed definition is based on the width of the response to a finite-impulse-type perturbation. The response is computed by convolving the filter coefficients with an impulse function, namely, a Kronecker delta function for smoothing filters, and a Heaviside step function for derivative filters. Once the response has been computed, the proposed standardized definition of vertical resolution is given by Δz = δz × HFWHM, where δz is the lidar's sampling resolution and HFWHM is the full width at half maximum (FWHM) of the response, measured in sampling intervals. The second proposed definition relates to digital filtering theory. After applying a Laplace transform to a set of filter coefficients, the filter's gain characterizing the effect of the filter on the signal in the frequency domain is computed, from which the cut-off frequency fC, defined as the frequency at which the gain equals 0.5, is computed. Vertical resolution is then defined by Δz = δz/(2fC). Unlike common practice in the field of spectral analysis, a factor 2fC instead of fC is used here to yield vertical resolution values nearly equal to the values obtained with the impulse response definition using the same filter coefficients. When using either of the proposed definitions, unsmoothed signals yield the best possible vertical resolution Δz = δz (one sampling bin). Numerical tools were developed to support the implementation of these definitions across all NDACC lidar groups. The tools consist of ready-to-use "plug-in" routines written in several programming languages that can be inserted into any lidar data processing software and

  11. Aerosolized Red Tide Toxins (Brevetoxins) and Asthma: Continued health effects after 1 hour beach exposure.

    PubMed

    Kirkpatrick, Barbara; Fleming, Lora E; Bean, Judy A; Nierenberg, Kate; Backer, Lorraine C; Cheng, Yung Sung; Pierce, Richard; Reich, Andrew; Naar, Jerome; Wanner, Adam; Abraham, William M; Zhou, Yue; Hollenbeck, Julie; Baden, Daniel G

    2011-01-01

    Blooms of the toxic dinoflagellate, Karenia brevis, produce potent neurotoxins in marine aerosols. Recent studies have demonstrated acute changes in both symptoms and pulmonary function in asthmatics after only 1 hour of beach exposure to these aerosols. This study investigated if there were latent and/or sustained effects in asthmatics in the days following the initial beach exposure during periods with and without an active Florida red tide.Symptom data and spirometry data were collected before and after 1 hour of beach exposure. Subjects kept daily symptom diaries and measured their peak flow each morning for 5 days following beach exposure. During non-exposure periods, there were no significant changes in symptoms or pulmonary function either acutely or over 5 days of follow-up. After the beach exposure during an active Florida red tide, subjects had elevated mean symptoms which did not return to the pre-exposure baseline for at least 4 days. The peak flow measurements decreased after the initial beach exposure, decreased further within 24 hours, and continued to be suppressed even after 5 days. Asthmatics may continue to have increased symptoms and delayed respiratory function suppression for several days after 1 hour of exposure to the Florida red tide toxin aerosols.

  12. 40 CFR 52.1683 - Control strategy: Ozone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 4 2013-07-01 2013-07-01 false Control strategy: Ozone. 52.1683...: Ozone. (a) The State of New York has certified to the satisfaction of the EPA that no sources are... Polystyrene Resins. (b)-(e) (f) Attainment Determination. (1) EPA is determining that the 1-hour...

  13. 40 CFR 52.1683 - Control strategy: Ozone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 4 2011-07-01 2011-07-01 false Control strategy: Ozone. 52.1683...: Ozone. (a) The State of New York has certified to the satisfaction of the EPA that no sources are... Polystyrene Resins. (b)-(e) (f) Attainment Determination. (1) EPA is determining that the 1-hour...

  14. 40 CFR 52.1683 - Control strategy: Ozone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.1683...: Ozone. (a) The State of New York has certified to the satisfaction of the EPA that no sources are... Polystyrene Resins. (b)-(e) (f) Attainment Determination. (1) EPA is determining that the 1-hour...

  15. 40 CFR 52.1683 - Control strategy: Ozone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 4 2012-07-01 2012-07-01 false Control strategy: Ozone. 52.1683...: Ozone. (a) The State of New York has certified to the satisfaction of the EPA that no sources are... Polystyrene Resins. (b)-(e) (f) Attainment Determination. (1) EPA is determining that the 1-hour...

  16. 40 CFR 52.1683 - Control strategy: Ozone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 4 2014-07-01 2014-07-01 false Control strategy: Ozone. 52.1683...: Ozone. (a) The State of New York has certified to the satisfaction of the EPA that no sources are... Manufacturing Materials. (2) (c)-(e) (f) Attainment Determination. (1) EPA is determining that the 1-hour...

  17. 75 FR 43069 - Approval of One-Year Extension for Attaining the 1997 8-Hour Ozone Standard in the Baltimore...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-23

    .... 40 CFR 51.907 sets forth how sections 172(a)(2)(C) and 181(a)(5) apply to an area subject to the 1997 8-hour ozone NAAQS. Under 40 CFR 51.907, an area will meet the requirement of section 172(a)(2)(C... Baltimore Moderate Nonattainment Area AGENCY: Environmental Protection Agency (EPA). ACTION: Direct...

  18. 76 FR 13289 - Approval of One-Year Extension for Attaining the 1997 8-Hour Ozone Standard in the Baltimore...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-11

    ... Appendix A can be found in the ``Quality Assurance Handbook for Air Pollution Measurement Systems,'' volume...).) List of Subjects in 40 CFR Part 81 Environmental protection, Air pollution control, National parks... Baltimore nonattainment area, which is classified as moderate for the 1997 8-hour ozone National Ambient...

  19. Ozone in the Atmosphere: II. The Lower Atmosphere.

    ERIC Educational Resources Information Center

    Phillips, Paul; Pickering, Pam

    1991-01-01

    Described are the problems caused by the increased concentration of ozone in the lower atmosphere. Photochemical pollution, mechanisms of ozone production, ozone levels in the troposphere, effects of ozone on human health and vegetation, ozone standards, and control measures are discussed. (KR)

  20. Observations of the Temperature Dependent Response of Ozone to NOx Reductions in an Urban Plume

    SciTech Connect

    LaFranchi, B W; Goldstein, A H; Cohen, R C

    2011-01-25

    Observations of NO{sub x} in the Sacramento, CA region show that mixing ratios decreased by 30% between 2001 and 2008. Here we use an observation-based method to quantify net ozone production rates in the outflow from the Sacramento metropolitan region and examine the O{sub 3} decrease resulting from reductions in NO{sub x} emissions. This observational method does not rely on assumptions about detailed chemistry of ozone production, rather it is an independent means to verify and test these assumptions. We use an instantaneous steady-state model as well as a detailed 1-D plume model to aid in interpretation of the ozone production inferred from observations. In agreement with the models, the observations show that early in the plume, the NO{sub x} dependence for O{sub x} (O{sub x} = O{sub 3}+NO{sub 2}) production is strongly coupled with temperature, suggesting that temperature dependent biogenic VOC emissions can drive O{sub x} production between NO{sub x}-limited and NO{sub x}-suppressed regimes. As a result, NO{sub x} reductions were found to be most effective at higher temperatures over the 7 year period. We show that violations of the California 1-hour O{sub 3} standard (90 ppb) in the region have been decreasing linearly with decreases in NO{sub x} (at a given temperature) and predict that reductions of NO{sub x} concentrations (and presumably emissions) by an additional 30% (relative to 2007 levels) will eliminate violations of the state 1 hour standard in the region. If current trends continue, a 30% decrease in NO{sub x} is expected by 2012, and an end to violations of the 1 hour standard in the Sacramento region appears to be imminent.

  1. Karlson ozone sterilizer. Final report

    SciTech Connect

    Karlson, E.

    1984-05-07

    The authors have a functional sterilization system employing ozone as a sterilization agent. This final report covers the work that led to the first medical sterilizer using ozone as the sterilizing agent. The specifications and the final design were set by hospital operating room personnel and public safety standards. Work on kill tests using bacteria, viruses and fungi determined the necessary time and concentration of ozone necessary for sterilization. These data were used in the Karlson Ozone Sterilizer to determine the length of the steps of the operating cycle and the concentration of ozone to be used. 27 references.

  2. Investigation of Ground-Level Ozone and High-Pollution Episodes in a Megacity of Eastern China

    PubMed Central

    Zhao, Heng; Wang, Shanshan; Wang, Wenxin; Liu, Rui; Zhou, Bin

    2015-01-01

    Differential Optical Absorption Spectroscopy (DOAS) was used for the long-term observation of ground-level ozone (O3) from March 2010 to March 2013 over Shanghai, China. The 1-hour average concentration of O3 was 27.2 ± 17.0 ppbv. O3 level increased during spring, reached the peak in late spring and early summer, and then decreased in autumn and finally dropped to the bottom in winter. The highest monthly average O3 concentration in June (41.1 ppbv) was nearly three times as high as the lowest level recorded in December (15.2 ppbv). In terms of pollution episodes, 56 hourly samples (on 14 separate days) in 2010 exceeded the 1-hour ozone limit of 200 μg/m3 specified by the Grade II of the Chinese Ambient Air Quality Standards (CAAQS, revised GB 3095-2012). Utilizing the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model, the primary contribution to high ozone days (HODs) was identified as the regional transportation of volatile organic compounds (VOC) and high concentrations of O3 from the chemical industrial zone in the Jinshan district of Shanghai. HODs showed higher concentrations of HONO and NO2 than non-episode conditions, implying that HONO at high concentration during HODs was capable of increasing the O3 concentration. The photolysis rate of HONO was estimated, suggesting that the larger number of OH radicals resulting from high concentrations of HONO have a considerable impact on ozone concentrations. PMID:26121146

  3. NODA for EPA's Updated Ozone Transport Modeling

    EPA Pesticide Factsheets

    Find EPA's NODA for the Updated Ozone Transport Modeling Data for the 2008 Ozone National Ambient Air Quality Standard (NAAQS) along with the ExitExtension of Public Comment Period on CSAPR for the 2008 NAAQS.

  4. Stratospheric ozone is decreasing

    NASA Astrophysics Data System (ADS)

    Kerr, Richard A.

    1988-03-01

    The recent discovery that chlorofluorocarbons create the Antarctic ozone hole every October through reactions mediated by ice particles formed at the lowest temperatures of the stratosphere is discussed. A large-scale reanalysis of measurements reveals that protective stratospheric ozone has decreased during the past 17 yrs with some decreases greatly exceeding predictions. It is noted that standard models did not, and still do not, include the ice in their reaction schemes. A tendency toward larger losses at higher colder latitudes is seen.

  5. UV/ozone cleaning of mass standards: results on the correlation between mass and surface chemical state

    NASA Astrophysics Data System (ADS)

    Fuchs, P.; Marti, K.; Grgić, G.; Russi, S.

    2014-10-01

    UV/ozone cleaning of 1 kg Au and steel mass artefacts was studied by direct mass comparison and surface chemical analysis by XPS. Both materials are oxidized with an increasing oxide layer thickness upon prolonged exposure time. The gain in mass is significant. The gold oxides are not stable and decompose with time in part at ambient. As shown for artefacts of stacked discs, cavities and interspaces were also cleaned, but with a much longer cleaning time. Stacked discs, having a completely different cleaning time, are questionable for the determination of sorption phenomena.

  6. Dose-response study of healthy, heavily exercising men exposed to ozone at concentrations near the ambient air quality standard

    SciTech Connect

    Linn, W.S.; Avol, E.L.; Shamoo, D.A.; Spier, C.E.; Valencia, L.M.; Venet, T.G.; Fischer, D.A.; Hackney, J.D.

    1986-07-01

    Twenty-four healthy, well-conditioned young adult male volunteers, free of asthma or clinical respiratory allergies, were exposed to purified air containing ozone (O3) at 0.16, 0.14, 0.12, 0.10, 0.08, and 0.00 part per million (ppm). Exposures were separated by 2-week intervals, occurred in random order, and lasted 2 hours each. Temperature was 32 +/- 1/sup 0/C and relative humidity was 38 +/- 3%, simulating Los Angeles area smog conditions. Subjects exercised 15 minutes of each half hour, attaining ventilation rates averaging 68 L/min (approximately 35 L/min per m2 body surface area). Lung function was measured pre-exposure and after 1 hr and 2 hr of exposure. Airway responsiveness to a cold-air challenge was measured immediately following the 2-hr exposure. Symptoms were recorded before, during, and for one-week periods following exposures. For the group as a whole, no meaningful untoward effects were found except for a mild typical respiratory irritant response after 2 hr exposure to 0.16 ppm O3. Two individual subjects showed possible responses at 0.14 ppm, and one of them also at 0.12 ppm. In comparison to some previous investigations, this study showed generally less response to O3. The comparative lack of response may relate to the favorable clinical status of the subjects, the pattern of exercise during exposure, or some other factor not yet identified.

  7. 40 CFR 52.2235 - Control strategy: Ozone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 4 2011-07-01 2011-07-01 false Control strategy: Ozone. 52.2235... strategy: Ozone. (a) Determination—EPA is determining that, as of August 8, 1995, the Nashville ozone nonattainment area has attained the ozone standard and that the reasonable further progress and...

  8. 40 CFR 52.2235 - Control strategy: Ozone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 5 2012-07-01 2012-07-01 false Control strategy: Ozone. 52.2235... strategy: Ozone. (a) Determination—EPA is determining that, as of August 8, 1995, the Nashville ozone nonattainment area has attained the ozone standard and that the reasonable further progress and...

  9. 40 CFR 52.2332 - Control Strategy: Ozone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 5 2013-07-01 2013-07-01 false Control Strategy: Ozone. 52.2332...: Ozone. Determinations—EPA is determining that, as of July 18, 1995, the Salt Lake and Davis Counties ozone nonattainment area has attained the ozone standard based on air quality monitoring data from...

  10. 40 CFR 52.1023 - Control strategy: Ozone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 4 2011-07-01 2011-07-01 false Control strategy: Ozone. 52.1023...: Ozone. (a) Determination. EPA is determining that, as of July 21, 1995, the Lewiston-Auburn ozone nonattainment area has attained the ozone standard and that the reasonable further progress and...

  11. 40 CFR 52.1023 - Control strategy: Ozone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.1023...: Ozone. (a) Determination. EPA is determining that, as of July 21, 1995, the Lewiston-Auburn ozone nonattainment area has attained the ozone standard and that the reasonable further progress and...

  12. 40 CFR 52.2332 - Control Strategy: Ozone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control Strategy: Ozone. 52.2332...: Ozone. Determinations—EPA is determining that, as of July 18, 1995, the Salt Lake and Davis Counties ozone nonattainment area has attained the ozone standard based on air quality monitoring data from...

  13. 40 CFR 52.1023 - Control strategy: Ozone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 4 2014-07-01 2014-07-01 false Control strategy: Ozone. 52.1023...: Ozone. (a) Determination. EPA is determining that, as of July 21, 1995, the Lewiston-Auburn ozone nonattainment area has attained the ozone standard and that the reasonable further progress and...

  14. 40 CFR 52.2332 - Control Strategy: Ozone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 5 2014-07-01 2014-07-01 false Control Strategy: Ozone. 52.2332...: Ozone. Determinations—EPA is determining that, as of July 18, 1995, the Salt Lake and Davis Counties ozone nonattainment area has attained the ozone standard based on air quality monitoring data from...

  15. 40 CFR 52.2332 - Control Strategy: Ozone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 4 2011-07-01 2011-07-01 false Control Strategy: Ozone. 52.2332...: Ozone. Determinations—EPA is determining that, as of July 18, 1995, the Salt Lake and Davis Counties ozone nonattainment area has attained the ozone standard based on air quality monitoring data from...

  16. 40 CFR 52.2235 - Control strategy: Ozone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 5 2014-07-01 2014-07-01 false Control strategy: Ozone. 52.2235... strategy: Ozone. (a) Determination—EPA is determining that, as of August 8, 1995, the Nashville ozone nonattainment area has attained the ozone standard and that the reasonable further progress and...

  17. 40 CFR 52.2332 - Control Strategy: Ozone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 5 2012-07-01 2012-07-01 false Control Strategy: Ozone. 52.2332...: Ozone. Determinations—EPA is determining that, as of July 18, 1995, the Salt Lake and Davis Counties ozone nonattainment area has attained the ozone standard based on air quality monitoring data from...

  18. 40 CFR 52.2235 - Control strategy: Ozone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 5 2013-07-01 2013-07-01 false Control strategy: Ozone. 52.2235... strategy: Ozone. (a) Determination—EPA is determining that, as of August 8, 1995, the Nashville ozone nonattainment area has attained the ozone standard and that the reasonable further progress and...

  19. 40 CFR 52.1023 - Control strategy: Ozone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 4 2013-07-01 2013-07-01 false Control strategy: Ozone. 52.1023...: Ozone. (a) Determination. EPA is determining that, as of July 21, 1995, the Lewiston-Auburn ozone nonattainment area has attained the ozone standard and that the reasonable further progress and...

  20. 40 CFR 52.1023 - Control strategy: Ozone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 4 2012-07-01 2012-07-01 false Control strategy: Ozone. 52.1023...: Ozone. (a) Determination. EPA is determining that, as of July 21, 1995, the Lewiston-Auburn ozone nonattainment area has attained the ozone standard and that the reasonable further progress and...

  1. 40 CFR 52.2235 - Control strategy: Ozone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Control strategy: Ozone. 52.2235... strategy: Ozone. (a) Determination—EPA is determining that, as of August 8, 1995, the Nashville ozone nonattainment area has attained the ozone standard and that the reasonable further progress and...

  2. The effect of the Standard Nomenclature for Air Pollution (SNAP) categories on ozone and PM2.5 concentrations over Europe

    NASA Astrophysics Data System (ADS)

    Tagaris, Efthimios; Sotiropoulou, Rafaella-Eleni P.; Gounaris, Nikos; Andronopoulos, Spyros; Vlachogiannis, Diamando

    2015-04-01

    The objective of this study is to estimate the contribution of different anthropogenic emission sources on ozone and PM2.5 concentrations over Europe since anthropogenic activities (and the related emissions) are the reason of air quality degradation. Gridded yearly averaged anthropogenic emissions for the year 2006 over Europe are provided by TNO at a 0.1×0.1 degree resolution. Emission sources have been classified into different activities according to the Standard Nomenclature for Air Pollution (SNAP). The available data include annual total emissions of CH4, CO, NH3, NMVOC, NOx, PM10, PM2.5, and SO2 for both area and point sources in ten (10) SNAP categories: power generation, residential-commercial and other combustion, industrial combustion, industrial processes, extraction distribution of fossil fuels, solvent use, road transport, other mobile sources, waste treatment and disposal, agriculture. Mobile sources and road transport are the major sources of NOx emissions followed by power generation units. Power generation is also the major source for SO2 emissions followed by mobile sources. Agricultural activities dominate NH3 emissions while combustion sources followed by mobile sources and road transport are the main sources for primary PM2.5. Emissions are processed by the Sparse Matrix Operator Kernel Emissions (SMOKE) v2.6 modeling system to convert their resolution to the resolution needed by the air quality model The Community Multiscale Air Quality (CMAQ) v4.7 Modeling System with the Carbon Bond mechanism (CB05) is used for the regional air quality modeling over Europe at 35km grid spacing. Results quantify the contribution of each SNAP category on ozone and PM2.5 concentrations, locally, across Europe.

  3. Ozone modeling in an ethanol, gasoline and diesel fuels environment: The metropolitan area of Sao Paulo, Brazil

    SciTech Connect

    Andrade, M.F.; Miguel, A.H.; Seinfeld, J.H.

    1995-12-01

    Over the past several years, in the Metropolitan Area of Sao Paulo (MASP), ambient ozone concentrations have reached over five times the concentration considered protective of public health by the World Health Organization, with routine occurrence of levels that exceed Brazil`s 1 hour National Ambient Air Quality Standard (160 {mu}g/m{sup 3}). For the past 19 years, ethanol has been used both as fuel (E95) and as gasoline additive (E20G80) in light duty vehicles. This talk will discuss the results of the application of the CIT photochemical airshed model to the February 16-17, 1989 meteorological experiment carried out in the MASP. Simulated hourly ozone concentrations for the 1989 vehicular fleet included three cases: (1) the actual fleet (F.95, E20G80, and diesels), (2) a light duty fleet fueled with E95 only, and (3) entirely with gasoline.

  4. 76 FR 72919 - Draft Integrated Science Assessment for Ozone and Related Photochemical Oxidants

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-28

    ... AGENCY Draft Integrated Science Assessment for Ozone and Related Photochemical Oxidants AGENCY..., ``Second External Review Draft Integrated Science Assessment for Ozone and Related Photochemical Oxidants... review of the national ambient air quality standards (NAAQS) for ozone. DATES: The public comment...

  5. 76 FR 17121 - Draft Integrated Science Assessment for Ozone and Related Photochemical Oxidants

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-03-28

    ... AGENCY Draft Integrated Science Assessment for Ozone and Related Photochemical Oxidants AGENCY..., ``First External Review Draft Integrated Science Assessment for Ozone and Related Photochemical Oxidants... review of the national ambient air quality standards (NAAQS) for ozone. DATES: The public comment...

  6. [Surface-enhanced Raman spectra of oxidation damnification of fetal bovine serum by ozone].

    PubMed

    Zou, Zu-Quan; Liu, Yan-Nan; Wu, Ying; Li, Qi-Nan; Chen, Mei-Zong; Sun, Hai-Ying; Lee, Imshik

    2007-06-01

    Fetal bovine serum was treated by ozone for 1 hour and 3 hours before getting its surface-enhanced Raman spectra from 200 to 1 800 cm(-1). Treated with ozone for 1 hour, it shows a significant decrease in band intensity. Treated with ozone for 3 hours, the band intensity has a further decrease but not so obviously, which means that oxidation of ozone is short lived. Treated with ozone, the orderly conformations of main chains in protein such as alpha-helix, beta-sheet and beta-corner are damaged seriously. Aromatic side chains and C-S of Cys and Met also are damnified greatly. All this means that strong oxidation of ozone results in denaturation, conformational changes and even degradation in protein.

  7. Investigating ozone in rural Nevada, USA: Results from the first year of the Nevada Rural Ozone Initiative (NVROI)

    NASA Astrophysics Data System (ADS)

    Gustin, M. S.; Fine, R.; Miller, M. B.; Peterson, C.; Burley, J. D.; Jaffe, D. A.

    2013-12-01

    Ozone has been measured at Great Basin National Park, located in a rural area of eastern Nevada, USA, since 1993. Observations at the Park indicate that the area likely will not be able to meet a revised U.S. National Ambient Air Quality Standard (NAAQS) of ≤ 70 ppbv. Routine ozone monitoring outside of the Park in Nevada has been limited to the two major metropolitan areas in the state, Reno and Las Vegas, and surrounding communities. To address this limitation, a research project, the Nevada Rural Ozone Initiative (NVROI), was put into place. The NVROI goals are to characterize ozone concentrations, and to determine the sources contributing to observed concentrations in Nevada, and regions of the western United States. The first year of the project focused on establishing a network of ozone monitoring sites. Based on the measurements from 5 sites across the state where data were collected from July 2011 to June 2012, seasonal mean (× s) concentrations ranged from 39×15 to 54×9 ppbv (spring); 36×14 to 54×8 ppbv (summer); 27×13 to 44×6 ppbv (fall); and 23×11 to 41×5 ppbv (winter) across the state, with higher mean concentrations observed at the high elevation sites. The average daily maximum 1-hour concentrations of ozone (× s) were similar across these sites ranging from 58×6 to 69×7 ppbv (spring); 53×6 to 62×9 ppbv (summer); 44×7 to 49×6 ppbv (fall); and 37×5 to 45×4 ppbv (winter). Periods of elevated ozone were observed at these 5 NVROI network sites (1513 to 2082 m above sea level (asl)). There were 15, 28, and 81 days with at least one NVROI site experiencing a Maximum Daily 8-hour Average (MDA8) greater than 70, 65, and 60 ppbv, respectively. Events (MDA8 > 60 ppbv) were coincident with (1) passage of frontal systems (spring and early summer events), or (2) the presence of smoke generated by regional wildfires and an area of low pressure over Nevada (summer events). Atmospheric turbulence and vertical lifting is associated with frontal

  8. Chlorophyll fluorescence quenching during ozone exposure of leaves of Phaseolus vulgaris (pinto)

    SciTech Connect

    Guralnick, L.J. ); Miller, R.; Heath, R.L. )

    1990-05-01

    During ozone exposure, observations have noted an initial decrease in CO{sub 2} uptake followed by a decrease in stomatal conductance. We examined this response utilizing the technique of fluorescence quenching. Fourteen day old plants were exposed to 0.3 ul/l ozone for 1 hour. Fluorescence quenching was monitored using the Hanstech modulated fluorescence system. This enabled us to measure changes in photochemical quenching (qQ) and non-photochemical quenching (qE) in control and ozone treated plants. Results have indicated no differences in qQ and qE between ozone treated and control plants. We are initiating further studies utilizing different ozone levels.

  9. Ozone Layer Protection

    MedlinePlus

    ... EPA United States Environmental Protection Agency Search Search Ozone Layer Protection Share Facebook Twitter Google+ Pinterest Contact Us Ozone Layer Protection Welcome to EPA's ozone layer protection web ...

  10. 40 CFR 51.905 - How do areas transition from the 1-hour NAAQS to the 1997 8-hour NAAQS and what are the anti...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... met its obligation to have a fully-approved attainment demonstration SIP for the 1-hour NAAQS, the... SIP at the time of the effective date of designation and in addition to national or regional measures... obligation for an approved 1-hour ROP SIP, it must develop and submit to EPA all outstanding 1-hour ROP...

  11. Ozone decomposition.

    PubMed

    Batakliev, Todor; Georgiev, Vladimir; Anachkov, Metody; Rakovsky, Slavcho; Zaikov, Gennadi E

    2014-06-01

    Catalytic ozone decomposition is of great significance because ozone is a toxic substance commonly found or generated in human environments (aircraft cabins, offices with photocopiers, laser printers, sterilizers). Considerable work has been done on ozone decomposition reported in the literature. This review provides a comprehensive summary of the literature, concentrating on analysis of the physico-chemical properties, synthesis and catalytic decomposition of ozone. This is supplemented by a review on kinetics and catalyst characterization which ties together the previously reported results. Noble metals and oxides of transition metals have been found to be the most active substances for ozone decomposition. The high price of precious metals stimulated the use of metal oxide catalysts and particularly the catalysts based on manganese oxide. It has been determined that the kinetics of ozone decomposition is of first order importance. A mechanism of the reaction of catalytic ozone decomposition is discussed, based on detailed spectroscopic investigations of the catalytic surface, showing the existence of peroxide and superoxide surface intermediates.

  12. Ozone decomposition

    PubMed Central

    Batakliev, Todor; Georgiev, Vladimir; Anachkov, Metody; Rakovsky, Slavcho

    2014-01-01

    Catalytic ozone decomposition is of great significance because ozone is a toxic substance commonly found or generated in human environments (aircraft cabins, offices with photocopiers, laser printers, sterilizers). Considerable work has been done on ozone decomposition reported in the literature. This review provides a comprehensive summary of the literature, concentrating on analysis of the physico-chemical properties, synthesis and catalytic decomposition of ozone. This is supplemented by a review on kinetics and catalyst characterization which ties together the previously reported results. Noble metals and oxides of transition metals have been found to be the most active substances for ozone decomposition. The high price of precious metals stimulated the use of metal oxide catalysts and particularly the catalysts based on manganese oxide. It has been determined that the kinetics of ozone decomposition is of first order importance. A mechanism of the reaction of catalytic ozone decomposition is discussed, based on detailed spectroscopic investigations of the catalytic surface, showing the existence of peroxide and superoxide surface intermediates. PMID:26109880

  13. Polar ozone

    NASA Technical Reports Server (NTRS)

    Solomon, S.; Grose, W. L.; Jones, R. L.; Mccormick, M. P.; Molina, Mario J.; Oneill, A.; Poole, L. R.; Shine, K. P.; Plumb, R. A.; Pope, V.

    1990-01-01

    The observation and interpretation of a large, unexpected ozone depletion over Antarctica has changed the international scientific view of stratospheric chemistry. The observations which show the veracity, seasonal nature, and vertical structure of the Antarctic ozone hole are presented. Evidence for Arctic and midlatitude ozone loss is also discussed. The chemical theory for Antarctic ozone depletion centers around the occurrence of polar stratospheric clouds (PSCs) in Antarctic winter and spring; the climatology and radiative properties of these clouds are presented. Lab studies of the physical properties of PSCs and the chemical processes that subsequently influence ozone depletion are discussed. Observations and interpretation of the chemical composition of the Antarctic stratosphere are described. It is shown that the observed, greatly enhanced abundances of chlorine monoxide in the lower stratosphere are sufficient to explain much if not all of the ozone decrease. The dynamic meteorology of both polar regions is given, interannual and interhemispheric variations in dynamical processes are outlined, and their likely roles in ozone loss are discussed.

  14. Local fluctuations of ozone from 16 km to 45 km deduced from in situ vertical ozone profile

    NASA Technical Reports Server (NTRS)

    Moreau, G.; Robert, C.

    1994-01-01

    A vertical ozone profile obtained by an in situ ozone sonde from 16 km to 45 km, has allowed to observe local ozone concentration variations. These variations can be observed, thanks to a fast measurement system based on a UV absorption KrF excimer laser beam in a multipass cell. Ozone standard deviation versus altitude calculated from the mean is derived. Ozone variations or fluctuations are correlated with the different dynamic zones of the stratosphere.

  15. Ozone inhibits prostacyclin synthesis in pulmonary endothelium.

    PubMed

    Friedman, M; Madden, M C; Saunders, D S; Gammon, K; White, G C; Kwock, L

    1985-12-01

    The effects of ozone on lung arachidonate metabolism in-vitro were studied in cultured bovine pulmonary endothelial cells exposed for 2 hours to ozone in concentrations up to 1.0 ppm. A concentration-dependent decrease in prostacyclin synthesis was found (90% decrease at the highest ozone level of 1.0 ppm). The inhibition of prostacyclin synthesis was not due to a decreased release of arachidonic acid from membrane lipids. We also examined the hypoxic pulmonary vasoconstrictive response to 10% oxygen inhalation in anesthetized dogs in-vivo after exposure to 1.0 ppm ozone for 1 hour. Pulmonary vascular resistance was significantly increased after ozone exposure, similar to the findings in dogs given indomethacin (15 mg/kg). The percentage change in the hypoxic pulmonary pressor response was similar between the ozone exposure and indomethacin-treated groups, although due to the variance of the pulmonary vascular resistance values during hypoxia the results did not reach statistical significance. These results suggest that ozone inhalation affects pulmonary endothelial arachidonate metabolism in-vivo as well as in-vitro.

  16. Ozone Reductions Using Residential Building Envelopes

    SciTech Connect

    Walker, Iain S.; Sherman, Max; Nazaroff, William W.

    2009-02-01

    Ozone is an air pollutant with that can have significant health effects and a significant source of ozone in some regions of California is outdoor air. Because people spend the vast majority of their time indoors, reduction in indoor levels of ozone could lead to improved health for many California residents. Ozone is removed from indoor air by surface reactions and can also be filtered by building envelopes. The magnitude of the envelope impact depends on the specific building materials that the air flows over and the geometry of the air flow paths through the envelope that can be changes by mechanical ventilation operation. The 2008 Residential Building Standards in California include minimum requirements for mechanical ventilation by referencing ASHRAE Standard 62.2. This study examines the changes in indoor ozone depending on the mechanical ventilation system selected to meet these requirements. This study used detailed simulations of ventilation in a house to examine the impacts of different ventilation systems on indoor ozone concentrations. The simulation results showed that staying indoors reduces exposure to ozone by 80percent to 90percent, that exhaust ventilation systems lead to lower indoor ozone concentrations, that opening of windows should be avoided at times of high outdoor ozone, and that changing the time at which mechanical ventilation occurs has the ability to halve exposure to ozone. Future work should focus on the products of ozone reactions in the building envelope and the fate of these products with respect to indoor exposures.

  17. Ozone absorption coefficients' role in Dobson instrument ozone measurement accuracy

    NASA Astrophysics Data System (ADS)

    Basher, R. E.

    1982-11-01

    The differences of 10% or more between the laboratory measurements of UV absorption coefficients by different investigators indicate accuracies that are quite inadequate for current needs in the measurement of atmospheric ozone. The standard band-integrated set of coefficients now used with the Dobson instrument are mutually consistent to about 2%, but their absolute accuracy is still in question. The accurate calculation of band-integrated coefficients must take account of their dependence on source spectral irradiance, atmospheric spectral transmittance, mean ozone temperature, and instrument spectral transmittance. A careful examination shows that Komhyr's (1980) case for an error of about +5% in the standard Dobson AD ozone estimation is subject to large uncertainties and certain lacks of independence. The obvious solution to this accuracy problem lies in better laboratory measurements of ozone absorption.

  18. Electroencephalogram (EEG) duration needed to detect abnormalities in angelman syndrome: is 1 hour of overnight recording sufficient?

    PubMed

    Robinson, Althea A; Goldman, Suzanne; Barnes, Gregory; Goodpaster, Luke; Malow, Beth A

    2015-01-01

    Approximately, 90% of patients with Angelman syndrome present with epileptic seizures. Obtaining an electroencephalogram (EEG) with sleep improves the chances of detecting ictal, interictal, and benign abnormal rhythms in Angelman syndrome. However, electroencephalograms, even when obtained during sleep, can be challenging in this population because of tactile sensitivities as well as anxiety related to a novel environment. We tested the hypothesis that 1 hour of sleep on an electroencephalogram would provide as much information as an entire night of electroencephalogram recording, yet more than a routine electroencephalogram conducted during the day. Overnight polysomnograms were collected in 14 children with Angelman syndrome seen at Vanderbilt University. All patients who obtained sleep within the first hour of the overnight electroencephalogram had interictal discharges recorded. Our results show that when sleep is obtained, a 1-hour electroencephalogram yields just as much information as recording an entire night.

  19. Ozone, Tropospheric

    NASA Technical Reports Server (NTRS)

    Fishman, Jack

    1995-01-01

    In the early part of the 20th century, ground-based and balloon-borne measurements discovered that most of atmosphere's ozone is located in the stratosphere with highest concentrations located between 15 and 30 km (9,3 and 18.6 miles). For a long time, it was believed that tropospheric ozone originated from the stratosphere and that most of it was destroyed by contact with the earth's surface. Ozone, O3, was known to be produced by the photo-dissociation of molecular oxygen, O2, a process that can only occur at wavelengths shorter than 242 nm. Because such short-wave-length radiation is present only in the stratosphere, no tropospheric ozone production is possible by this mechanism. In the 1940s, however, it became obvious that production of ozone was also taking place in the troposphere. The overall reaction mechanism was eventually identified by Arie Haagen-Smit of the California Institute of Technology, in highly polluted southern California. The copious emissions from the numerous cars driven there as a result of the mass migration to Los Angeles after World War 2 created the new unpleasant phenomenon of photochemical smog, the primary component of which is ozone. These high levels of ozone were injuring vegetable crops, causing women's nylons to run, and generating increasing respiratory and eye-irritation problems for the populace. Our knowledge of tropospheric ozone increased dramatically in the early 1950s as monitoring stations and search centers were established throughout southern California to see what could be done to combat this threat to human health and the environment.

  20. 40 CFR 52.1174 - Control strategy: Ozone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    .... Appropriateness of a contingency measure will be determined by an urban airshed modeling analysis. The Governor or... NAAQS, determined not to be attributable to transport from upwind areas, is monitored, Michigan will... the area records a violation of the 1-hour ozone NAAQS, determined not to be attributable to...

  1. Electrical stimulation of embryonic neurons for 1 hour improves axon regeneration and the number of reinnervated muscles that function.

    PubMed

    Liu, Yang; Grumbles, Robert M; Thomas, Christine K

    2013-07-01

    Motoneuron death after spinal cord injury or disease results in muscle denervation, atrophy, and paralysis. We have previously transplanted embryonic ventral spinal cord cells into the peripheral nerve to reinnervate denervated muscles and to reduce muscle atrophy, but reinnervation was incomplete. Here, our aim was to determine whether brief electrical stimulation of embryonic neurons in the peripheralnerve changes motoneuron survival, axon regeneration, and muscle reinnervation and function because neural depolarization is crucial for embryonic neuron survival and may promote activity-dependent axon growth. At 1 week after denervation by sciatic nerve section, embryonic day 14 to 15 cells were purified for motoneurons, injected into the tibial nerve of adult Fischer rats, and stimulated immediatelyfor up to 1 hour. More myelinated axons were present in tibial nerves 10 weeks after transplantation when transplants had been stimulated acutely at 1 Hz for 1 hour. More muscles were reinnervated if the stimulation treatment lasted for 1 hour. Reinnervation reduced muscle atrophy, with or without the stimulation treatment. These data suggest that brief stimulation of embryonic neurons promotes axon growth, which has a long-term impact on muscle reinnervation and function. Muscle reinnervation is important because it may enable the use of functional electrical stimulation to restore limb movements.

  2. Electrical Stimulation of Embryonic Neurons for 1 Hour Improves Axon Regeneration and the Number of Reinnervated Muscles that Function

    PubMed Central

    Liu, Yang; Grumbles, Robert M.; Thomas, Christine K.

    2013-01-01

    Motoneuron death following spinal cord injury or disease results in muscle denervation, atrophy, and paralysis. We have previously transplanted embryonic ventral spinal cord cells into peripheral nerve to reinnervate denervated muscles and to reduce muscle atrophy, but reinnervation was incomplete. Here, our aim was to determine whether brief electrical stimulation of embryonic neurons in peripheral nerve changes motoneuron survival, axon regeneration, and muscle reinnervation and function because neural depolarization is crucial for embryonic neuron survival and may promote activity-dependent axon growth. At 1 week after denervation by sciatic nerve section, embryonic day 14-15 cells were purified for motoneurons, injected into the tibial nerve of adult Fischer rats, and stimulated immediately for up to 1 hour. More myelinated axons were present in tibial nerves when transplants had been stimulated at 1 Hz for 1 hour at 10 weeks following transplantation. More muscles were reinnervated if the stimulation treatment lasted for 1 hour. Reinnervation reduced muscle atrophy, with or without the stimulation treatment. These data suggest that brief stimulation of embryonic neurons promotes axon growth, which has a long-term impact on muscle reinnervation and function. Muscle reinnervation is important because it may enable the use of functional electrical stimulation to restore limb movements. PMID:23771218

  3. Computer model predictions of the local effects of large, solid-fuel rocket motors on stratospheric ozone. Technical report

    SciTech Connect

    Zittel, P.F.

    1994-09-10

    The solid-fuel rocket motors of large space launch vehicles release gases and particles that may significantly affect stratospheric ozone densities along the vehicle's path. In this study, standard rocket nozzle and flowfield computer codes have been used to characterize the exhaust gases and particles through the afterburning region of the solid-fuel motors of the Titan IV launch vehicle. The models predict that a large fraction of the HCl gas exhausted by the motors is converted to Cl and Cl2 in the plume afterburning region. Estimates of the subsequent chemistry suggest that on expansion into the ambient daytime stratosphere, the highly reactive chlorine may significantly deplete ozone in a cylinder around the vehicle track that ranges from 1 to 5 km in diameter over the altitude range of 15 to 40 km. The initial ozone depletion is estimated to occur on a time scale of less than 1 hour. After the initial effects, the dominant chemistry of the problem changes, and new models are needed to follow the further expansion, or closure, of the ozone hole on a longer time scale.

  4. Stricter clean air standards

    SciTech Connect

    Schell, D.

    1997-07-01

    New standards for ozone and particulate matter stir a debate between the EPA and industrial groups. The article discusses both the history of the ozone and particulates standards, the goal of the EPA to protect health and evaluation of what the standards mean to health, and the industrial response.

  5. 40 CFR 51.905 - How do areas transition from the 1-hour NAAQS to the 8-hour NAAQS and what are the anti...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS REQUIREMENTS FOR PREPARATION, ADOPTION, AND SUBMITTAL OF IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National...) Submit an 8-hour ozone attainment demonstration no later than 1 year following designations...

  6. 40 CFR 51.905 - How do areas transition from the 1-hour NAAQS to the 8-hour NAAQS and what are the anti...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS REQUIREMENTS FOR PREPARATION, ADOPTION, AND SUBMITTAL OF IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National...) Submit an 8-hour ozone attainment demonstration no later than 1 year following designations...

  7. Tropopause Ozone

    NASA Astrophysics Data System (ADS)

    Prather, M.; Zhu, X.; Hsu, J.; Neu, J.; Tang, Q.

    2009-04-01

    The tropopause, however defined, is meant to describe the boundary between the well mixed troposphere and the stably stratified stratosphere. Ozone abundances in the vicinity of the tropopause exhibit large variations with latitude and season, being controlled by a combination of large-scale transport like the Brewer-Dobson circulation, small-scale turbulent mixing unresolved by global models, and photochemistry. A clear, instantaneous, 3-D definition of the tropopause is needed for diagnostics that separate stratosphere from troposphere, e.g., strat-trop exchange fluxes. In the UCI CTM, we define the stratosphere-troposphere boundary with what is effectively an age-of-air tracer: a tracer emitted uniformly from the surface with a uniform e-fold of 90 days (designated e90). Where the abundance of e90 falls below about 70% of the mass-median value (i.e., 33 days-old), we define as the stratosphere. With this diagnostic of the mixing barrier between stratosphere and troposphere the CTM with EC IFS forecast meteorology is able to match much of the observed seasonal cycle of the tropopause pressure and ozone abundance. With the CTM we examine the importance of chemistry vs. transport in controlling tropopause ozone. For example, we note that photolysis of molecular oxygen in the upper troposphere contributes significantly to tropopause ozone in the tropics and sub-tropics.

  8. 40 CFR 52.1486 - Control strategy: Hydrocarbons and ozone.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ozone. 52.1486 Section 52.1486 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... strategy: Hydrocarbons and ozone. (a) The requirements of subpart G of this chapter are not met since the plan does not provide for the attainment and maintenance of the national standard for ozone in the...

  9. 40 CFR 52.1486 - Control strategy: Hydrocarbons and ozone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... ozone. 52.1486 Section 52.1486 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... strategy: Hydrocarbons and ozone. (a) The requirements of subpart G of this chapter are not met since the plan does not provide for the attainment and maintenance of the national standard for ozone in the...

  10. 40 CFR 52.1486 - Control strategy: Hydrocarbons and ozone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... ozone. 52.1486 Section 52.1486 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... strategy: Hydrocarbons and ozone. (a) The requirements of subpart G of this chapter are not met since the plan does not provide for the attainment and maintenance of the national standard for ozone in the...

  11. 40 CFR 52.1486 - Control strategy: Hydrocarbons and ozone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... ozone. 52.1486 Section 52.1486 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... strategy: Hydrocarbons and ozone. (a) The requirements of subpart G of this chapter are not met since the plan does not provide for the attainment and maintenance of the national standard for ozone in the...

  12. 40 CFR 52.1486 - Control strategy: Hydrocarbons and ozone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... ozone. 52.1486 Section 52.1486 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... strategy: Hydrocarbons and ozone. (a) The requirements of subpart G of this chapter are not met since the plan does not provide for the attainment and maintenance of the national standard for ozone in the...

  13. Nonattainment and Ozone Transport Region (OTR) SIP Requirements

    EPA Pesticide Factsheets

    The Clean Air Act (CAA) requires a group of northeast states, which make up the Ozone Transport Region (OTR), to submit a SIP and install a certain level of controls for the pollutants that form ozone, even if they meet ozone standards.

  14. Y-12 Plant Stratospheric Ozone Protection plan

    SciTech Connect

    1995-09-01

    The Y-12 Plant staff is required by Lockheed Martin Energy Systems (Energy Systems) (formerly Martin Marietta Energy Systems) standard ESS-EP-129 to develop and implement a Stratospheric Ozone Protection Program which will minimize emissions of ozone-depleting substances to the environment and maximize the use of ozone-safe alternatives in order to comply with Title VI of the 1990 Clean Air Act (CAA) Amendments and the implementing regulations promulgated by the Environmental Protection Agency (EPA). This plan describes the requirements, initiatives, and accomplishments of the Y-12 Plant Stratospheric Ozone Protection Program.

  15. The Antarctic Ozone Hole

    ERIC Educational Resources Information Center

    Jones, Anna E.

    2008-01-01

    Since the mid 1970s, the ozone layer over Antarctica has experienced massive destruction during every spring. In this article, we will consider the atmosphere, and what ozone and the ozone layer actually are. We explore the chemistry responsible for the ozone destruction, and learn about why conditions favour ozone destruction over Antarctica. For…

  16. Proposed standardized definitions for vertical resolution and uncertainty in the NDACC lidar ozone and temperature algorithms - Part 3: Temperature uncertainty budget

    NASA Astrophysics Data System (ADS)

    Leblanc, Thierry; Sica, Robert J.; van Gijsel, Joanna A. E.; Haefele, Alexander; Payen, Guillaume; Liberti, Gianluigi

    2016-08-01

    A standardized approach for the definition, propagation, and reporting of uncertainty in the temperature lidar data products contributing to the Network for the Detection for Atmospheric Composition Change (NDACC) database is proposed. One important aspect of the proposed approach is the ability to propagate all independent uncertainty components in parallel through the data processing chain. The individual uncertainty components are then combined together at the very last stage of processing to form the temperature combined standard uncertainty. The identified uncertainty sources comprise major components such as signal detection, saturation correction, background noise extraction, temperature tie-on at the top of the profile, and absorption by ozone if working in the visible spectrum, as well as other components such as molecular extinction, the acceleration of gravity, and the molecular mass of air, whose magnitudes depend on the instrument, data processing algorithm, and altitude range of interest. The expression of the individual uncertainty components and their step-by-step propagation through the temperature data processing chain are thoroughly estimated, taking into account the effect of vertical filtering and the merging of multiple channels. All sources of uncertainty except detection noise imply correlated terms in the vertical dimension, which means that covariance terms must be taken into account when vertical filtering is applied and when temperature is integrated from the top of the profile. Quantitatively, the uncertainty budget is presented in a generic form (i.e., as a function of instrument performance and wavelength), so that any NDACC temperature lidar investigator can easily estimate the expected impact of individual uncertainty components in the case of their own instrument. Using this standardized approach, an example of uncertainty budget is provided for the Jet Propulsion Laboratory (JPL) lidar at Mauna Loa Observatory, Hawai'i, which is

  17. Evidence for vertical ozone redistribution since 1967

    NASA Astrophysics Data System (ADS)

    Furrer, R.; Döhler, W.; Kirsch, H.-J.; Plessing, P.; Görsdorf, U.

    1993-03-01

    Long-term measurements of the ozone concentration in the vicinity of the city of Berlin have been performed with ground based Dobson spectrophotometers and balloon borne systems. The respective experiments cover the past 24 years. All data have been reevaluated and corrected towards uniform calibration standards, leading to the longest European data set of total column density, altitude-dependent ozone partial pressures and the corresponding temperatures. Smoothing algorithms unravel significant long-term trends. The analysis shows an increase of ozone concentration within the middle stratosphere (below 31 km height) as well as in the troposphere over the past 24 years. On the contrary, ongoing ozone depletion in the lower stratosphere has been found. The large scale vertical redistribution of atmospheric ozone in the troposphere and the lower stratosphere seems to be in agreement with model calculations and trend predictions that have their roots in changes of the chemical composition and the ozone photochemistry due to anthropogenically induced trace gas concentrations.

  18. Evidence for vertical ozone redistribution since 1967

    NASA Astrophysics Data System (ADS)

    Furrer, R.; Döhler, W.; Kirsch, H.-J.; Plessing, P.; Görsdorf, U.

    1993-01-01

    Long-term measurements of ozone concentration in the vicinity of the city of Berlin have been performed with ground-based Dobson spectrophotometers and balloon borne systems. The respective experiments cover the past 24 yr. All data have been re-evaluated and corrected towards uniform calibration standards, leading to the longest lasting European data set of total column density, altitude-dependent ozone partial pressures and the corresponding temperatures. Smoothing algorithms reveal significant longterm trends. The analysis shows an increase of ozone concentration within the middle stratosphere (below 31 km height) as well as in the troposphere over the past 24 yr. On the contrary, ongoing ozone depletion in the lower stratosphere became evident. The large scale vertical redistribution of atmospheric ozone in the troposphere and the lower stratosphere seems to be in agreement with model calculations and trend predictions that have their roots in changes of the chemical composition and the ozone photochemistry due to anthropogenically induced tracer gas concentrations.

  19. Ozone Risk Assessment Utilities

    SciTech Connect

    Whitfield, R. G.; Jusko, M. J.; Clemmons, M. A.

    1999-08-10

    ORAMUS is a user-friendly, menu-driven software system that calculates and displays user-selected risk estimates for health effects attributable to short-term exposure to tropospheric ozone. Inputs to the risk assessment are estimates of exposure to ozone and exposure-response relationships to produce overall risk estimates in the form of probability distributions. Three fundamental models are included: headcount risk, benchmark risk, and hospital admissions. Exposure-response relationships are based on results of controlled human exposure studies. Exposure estimates are based on the EPA''s probabilistic national ambient air quality standards (NAAQS) exposure model, pNEM/Osub3, which simulates air quality associated with attainment of alternative NAAQS. Using ORAMUS, risk results for 27 air quality scenarios, air quality in 9 urban areas, 33 health endpoints, and 4 chronic health endpoints can be calculated.

  20. In vitro testing of a denture cleaning method using ozone.

    PubMed

    Oizumi, M; Suzuki, T; Uchida, M; Furuya, J; Okamoto, Y

    1998-06-01

    The purpose of this study was to compare the microbicidal effect of gaseous ozone with that of ozonated water in order to determine its usefulness as a method for disinfecting dentures. Although a large number of research studies have been done on the bactericidal effect of ozone, little is known about its microbicidal effects on oral microorganisms. Therefore, we tested the effect of ozone on three standard strains of oral microorganisms: Streptococcus mutans (strain IID 973), Staphylococcus aureus (strain 209-P), and Candida albicans (strain LAM 14322). When the gaseous ozone injection method was used, the numbers of cells of all three strains decreased to 1/10(5) at 1 min, and by 3 min they were below the detection limit. Thus, the microbicidal effect of gaseous ozone was ascertained in a short time. In contrast, when ozonated water at 1 ppm and 3 ppm was used, C. albicans decreased to 1/10. A 700 mg/h ozone production level was needed to prepare 1 ppm ozonated water, whereas 20 mg/h of ozone was required by the gaseous ozone generator. These findings indicate that direct exposure to gaseous ozone seems to be a more effective microbicide compared with ozonated water, and that gaseous ozone can be clinically useful for disinfection of dentures.

  1. Sensitivity modeling study for an ozone occurrence during the 1996 Paso Del Norte Ozone Campaign.

    PubMed

    Lu, Duanjun; Reddy, Remata S; Fitzgerald, Rosa; Stockwell, William R; Williams, Quinton L; Tchounwou, Paul B

    2008-12-01

    Surface ozone pollution has been a persistent environmental problem in the US and Europe as well as the developing countries. A key prerequisite to find effective alternatives to meeting an ozone air quality standard is to understand the importance of local anthropogenic emissions, the significance of biogenic emissions, and the contribution of long-range transport. In this study, an air quality modeling system that includes chemistry and transport, CMAQ, an emission processing model, SMOKE, and a mesoscale numerical meteorological model, WRF, has been applied to investigate an ozone event occurring during the period of the 1996 Paso del Norte Ozone Campaign. The results show that the modeling system exhibits the capability to simulate this high ozone occurrence by providing a comparable temporal variation of surface ozone concentration at one station and to capture the spatial evolution of the event. Several sensitivity tests were also conducted to identify the contributions to high surface ozone concentration from eight VOC subspecies, biogenic VOCs, anthropogenic VOCs and long-range transportation of ozone and its precursors. It is found that the reductions of ETH, ISOP, PAR, OLE and FORM help to mitigate the surface ozone concentration, and like anthropogenic VOCs, biogenic VOC plays a nonnegligible role in ozone formation. But for this case, long-range transport of ozone and its precursors appears to produce an insignificant contribution.

  2. Earth's Endangered Ozone

    ERIC Educational Resources Information Center

    Panofsky, Hans A.

    1978-01-01

    Included are (1) a discussion of ozone chemistry; (2) the effects of nitrogen fertilizers, fluorocarbons, and high level aircraft on the ozone layer; and (3) the possible results of a decreasing ozone layer. (MR)

  3. 75 FR 2935 - Extension of Deadline for Promulgating Designations for the 2008 Ozone National Ambient Air...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-01-19

    ... Protection Agency 40 CFR Parts 50, 58 and 81 Ozone National Ambient Air Quality Standards; Final Rule and... Designations for the 2008 Ozone National Ambient Air Quality Standards AGENCY: Environmental Protection Agency... promulgating initial area designations for the ozone national ambient air quality standards (NAAQS) that...

  4. Ozone NAAQS Review: Policy Assessment

    EPA Science Inventory

    Ozone is one of the six major air pollutants for which EPA has issued air quality criteria and established national ambient air quality standards (NAAQS) based on those criteria. The Clean Air Act (CAA) requires EPA to periodically review and revise, as appropriate, existing air...

  5. An Integrated 0-1 Hour First-Flash Lightning Nowcasting, Lightning Amount and Lightning Jump Warning Capability

    NASA Technical Reports Server (NTRS)

    Mecikalski, John; Jewett, Chris; Carey, Larry; Zavodsky, Brad; Stano, Geoffrey; Chronis, Themis

    2015-01-01

    Using satellite-based methods that provide accurate 0-1 hour convective initiation (CI) nowcasts, and rely on proven success coupling satellite and radar fields in the Corridor Integrated Weather System (CIWS; operated and developed at MIT-Lincoln Laboratory), to subsequently monitor for first-flash lightning initiation (LI) and later period lightning trends as storms evolve. Enhance IR-based methods within the GOES-R CI Algorithm (that must meet specific thresholds for a given cumulus cloud before the cloud is considered to have an increased likelihood of producing lightning next 90 min) that forecast LI. Integrate GOES-R CI and LI fields with radar thresholds (e.g., first greater than or equal to 40 dBZ echo at the -10 C altitude) and NWP model data within the WDSS-II system for LI-events from new convective storms. Track ongoing lightning using Lightning Mapping Array (LMA) and pseudo-Geostationary Lightning Mapper (GLM) data to assess per-storm lightning trends (e.g., as tied to lightning jumps) and outline threat regions. Evaluate the ability to produce LI nowcasts through a "lightning threat" product, and obtain feedback from National Weather Service forecasters on its value as a decision support tool.

  6. A periodicity of approximately 1 hour in X-ray emission from the active galaxy RE J1034+396.

    PubMed

    Gierliński, Marek; Middleton, Matthew; Ward, Martin; Done, Chris

    2008-09-18

    Active galactic nuclei and quasars are thought to be scaled-up versions of Galactic black hole binaries, powered by accretion onto supermassive black holes with masses of 10(6)-10(9) M[symbol: see text], as opposed to the approximately 10 M [symbol: see text] in binaries (here M [symbol: see text] is the solar mass). One example of the similarities between these two types of systems is the characteristic rapid X-ray variability seen from the accretion flow. The power spectrum of this variability in black hole binaries consists of a broad noise with multiple quasi-periodic oscillations superimposed on it. Although the broad noise component has been observed in many active galactic nuclei, there have hitherto been no significant detections of quasi-periodic oscillations. Here we report the discovery of an approximately 1-hour X-ray periodicity in a bright active galaxy, RE J1034+396. The signal is highly statistically significant (at the 5.6 sigma level) and very coherent, with quality factor Q > 16. The X-ray modulation arises from the direct vicinity of the black hole.

  7. Impact of enhanced ozone deposition and halogen chemistry on tropospheric ozone over the Northern Hemisphere

    EPA Science Inventory

    Fate of ozone in marine environments has been receiving increased attention due to the tightening of ambient air quality standards. The role of deposition and halogen chemistry is examined through incorporation of an enhanced ozone deposition algorithm and inclusion of halogen ch...

  8. Ozone Hole Over Antarctica

    NASA Technical Reports Server (NTRS)

    2002-01-01

    These images from the Total Ozone Mapping Spectrometer (TOMS) show the progressive depletion of ozone over Antarctica from 1979 to 1999. This 'ozone hole' has extended to cover an area as large as 10.5 million square miles in September 1998. The previous record of 10.0 million square miles was set in 1996. The Antarctic ozone hole develops each year between late August and early October. Regions with higher levels of ozone are shown in red. NASA and NOAA instruments have been measuring Antarctic ozone levels since the early 1970s. Large regions of depleted ozone began to develop over Antarctica in the early 1980s. Ozone holes of substantial size and depth are likely to continue to form during the next few years, scientists hope to see a reduction in ozone loss as levels of ozone-destroying CFCs (chlorofluorocarbons) are gradually reduced. Credit: Images by Greg Shirah, NASA Goddard Space Flight Center Scientific Visualization Studio

  9. The Antarctic ozone hole

    NASA Astrophysics Data System (ADS)

    Molina, Mario J.

    Observations of Antarctic ozone levels and the discovery of a hole in the Antarctic region are examined. The effects of chlorofluorocarbons (CFCs) on the level of stratospheric ozone are analyzed. Three cycles explaining the cause of ozone depletion in the poles are proposed. A comparison of field data and proposed depletion cycles reveals that the chemical origin of the ozone hole is due to CFCs. The potential global effects of the Antarctic ozone hole are discussed.

  10. Variations in the Martian Ozone Layer during 2004-2012

    NASA Astrophysics Data System (ADS)

    Lefevre, F.; Bertaux, J.; Montmessin, F.

    2012-12-01

    Ozone on Mars is a secondary product of CO2 photolysis and is rapidly destroyed (~1 hour) by H, OH, and HO2 radicals. This tight coupling between ozone and HOx species makes ozone a useful tracer of the hydrogen chemistry that stabilizes the CO2 atmosphere of Mars, and ozone measurements offer a powerful constraint for photochemical models. We present observations of the Martian ozone layer performed during 2004-2012 from the SPICAM spectrometer on board Mars Express. SPICAM measures the ultraviolet spectrum transmitted by the atmosphere between 118 and 320 nm in various modes of observation. We will focus here on the data acquired in nadir mode allowing the determination of the vertically-integrated ozone column. The dataset acquired since January 2004 has a near-global coverage and covers more than 4 Martian years. We will discuss the variability of ozone at the day-to-day, seasonal and interannual scales, and the measurements will be compared to three-dimensional model simulations to evaluate our quantitative understanding of Mars photochemistry.

  11. Assessing Ozone Forecast Uncertainty with a Data Assimilation System

    NASA Astrophysics Data System (ADS)

    Coy, L.; Allen, D.; Eckermann, S. D.; McCormack, J.; Stajner, I.; Hogan, T.

    2006-12-01

    The increments or observation minus forecast (O-F) statistics produced by a data assimilation system provides a ready-made method of evaluating forecast skill. In this study, O-F statistics from the Global Ozone Assimilation Testing System (GOATS) are used to examine how ozone assimilation products and their associated O-F statistics depend on input data biases, ozone chemistry parameterizations, and forecast model variances. All the GOATS results shown are based on a 6-hour forecast and analysis cycle using observations from SBUV/2 (Solar Backscatter Ultraviolet Radiometer-2) during September--October~2002. Results show that using an ozone chemistry parameterization can provide a built-in standard for assessing observational bias that is lacking in a passive ozone advection model. This is because a passive tracer advection model is usually limited in how strongly it can change mean values, leaving global mean ozone to be data driven. These results answer the problem of why ozone assimilation with parameterized chemistry often have larger mean 0-Fs than passive ozone assimilation: the larger mean O-Fs with a chemistry parameterization reflects the ozone model's active contribution to the ozone assimilation. Results also show that including an ozone chemistry parameterization can lead to a significant reduction of the RMS O-Fs by both reducing the ozone forecast model variance as well as improving the covariance between the ozone forecast and observations. Understanding the O-F statistics from an ozone data assimilation system can lead to improved use of O-F statistics in diagnosing ozone and other tracer forecast skill and in monitoring operational ozone assimilation systems.

  12. Statistical analysis and multi-instrument overview of the quasi-periodic 1-hour pulsations in Saturn's outer magnetosphere

    NASA Astrophysics Data System (ADS)

    Palmaerts, B.; Roussos, E.; Krupp, N.; Kurth, W. S.; Mitchell, D. G.; Yates, J. N.

    2016-06-01

    The in-situ exploration of the magnetospheres of Jupiter and Saturn has revealed different periodic processes. In particular, in the Saturnian magnetosphere, several studies have reported pulsations in the outer magnetosphere with a periodicity of about 1 h in the measurements of charged particle fluxes, plasma wave, magnetic field strength and auroral emissions brightness. The Low-Energy Magnetospheric Measurement System detector of the Magnetospheric Imaging Instrument (MIMI/LEMMS) on board Cassini regularly detects 1-hour quasi-periodic enhancements in the intensities of electrons with an energy range from a hundred keV to several MeV. We extend an earlier survey of these relativistic electron injections using 10 years of LEMMS observations in addition to context measurements by several other Cassini magnetospheric experiments. The one-year extension of the data and a different method of detection of the injections do not lead to a discrepancy with the results of the previous survey, indicating an absence of a long-term temporal evolution of this phenomenon. We identified 720 pulsed events in the outer magnetosphere over a wide range of latitudes and local times, revealing that this phenomenon is common and frequent in Saturn's magnetosphere. However, the distribution of the injection events presents a strong local time asymmetry with ten times more events in the duskside than in the dawnside. In addition to the study of their topology, we present a first statistical analysis of the pulsed events properties. The morphology of the pulsations shows a weak local time dependence which could imply a high-latitude acceleration source. We provide some clues that the electron population associated with this pulsed phenomenon is distinct from the field-aligned electron beams previously observed in Saturn's magnetosphere, but both populations can be mixed. We have also investigated the signatures of each electron injection event in the observations acquired by the Radio

  13. GOES Infrared and Reflectance 0-1 hour Lightning Initiation Indicators: Development and Initial Testing within a Convective Nowcasting System

    NASA Astrophysics Data System (ADS)

    Mecikalski, J. R.; Harris, R.; MacKenzie, W.; Durkee, P. A.; Iskenderian, H.; Bickmeier, L.; Nielsen, K. E.

    2010-12-01

    Within cumulus cloud fields that develop in conditionally unstable air masses, only a fraction of the cumuli may eventually develop into deep convection. Identifying which of these convective clouds most likely to generate lightning often starts with little more than a qualitative visual satellite analysis. The goal of this study is to identify the observed satellite infrared (IR) signatures associated with growing cumulus clouds prior to the first lightning strike, so-called lightning initiation (LI). This study quantifies the behavior of ten Geostationary Operational Environmental Satellite (GOES-12) IR interest fields in the 1-hour in advance of LI. A total of 172 lightning-producing storms that occurred during the 2009 convective season are manually tracked and studied over four regions: Northern Alabama, Central Oklahoma, the Kennedy Space Center and Washington D.C. Four-dimensional and cloud-to-ground lightning array data provide a total cloud lightning picture (in-cloud, cloud-to-cloud, cloud-to-air, cloud-to-ground) and thus precise LI points for each storm in both time and space. Statistical significance tests are conducted on observed trends for each of the ten LI fields to determine the unique information each field provides in terms of behavior prior to LI. Eight out of ten LI fields exhibited useful information at least 15 min in advance of LI, with 35 min being the average. Statistical tests on these eight fields are compared for separate large geographical areas. IR temperature thresholds are then determined as an outcome, which may be valuable when implementing a LI prediction algorithm into real-time satellite-based systems. The key LI indicators from GOES IR data (as well as 3.9 μm reflectance) will be presented. Beginning in 2010, the feasibility of using the satellite-based LI indicators found in the above analysis to forecast first lightning will be assessed within the Federal Aviation Administration’s (FAA) CoSPA nowcasting system. The goal

  14. Ground-level Ozone (Smog) Information | New England | US ...

    EPA Pesticide Factsheets

    2017-02-16

    Ground-level ozone presents a serious air quality problem in New England. In 2008, EPA revised the ozone standard to a level of 0.075 parts per million, 8-hour average. Over the last 5 years (2006 through 2010), there have been an average of 31 days per summer when New England's air exceeded this standard.

  15. Ground-level Ozone (Smog) Information | New England | US ...

    EPA Pesticide Factsheets

    2017-04-10

    Ground-level ozone presents a serious air quality problem in New England. In 2008, EPA revised the ozone standard to a level of 0.075 parts per million, 8-hour average. Over the last 5 years (2006 through 2010), there have been an average of 31 days per summer when New England's air exceeded this standard.

  16. An Integrated 0-1 Hour First-Flash Lightning Nowcasting, Lightning Amount and Lightning Jump Warning Capability

    NASA Technical Reports Server (NTRS)

    Mecikalski, John; Jewett, Chris; Carey, Larry; Zavodsky, Brad; Stano, Geoffrey

    2015-01-01

    Lightning one of the most dangerous weather-related phenomena, especially as many jobs and activities occur outdoors, presenting risk from a lightning strike. Cloud-to-ground (CG) lightning represents a considerable safety threat to people at airfields, marinas, and outdoor facilities-from airfield personnel, to people attending outdoor stadium events, on beaches and golf courses, to mariners, as well as emergency personnel. Holle et al. (2005) show that 90% of lightning deaths occurred outdoors, while 10% occurred indoors despite the perception of safety when inside buildings. Curran et al. (2000) found that nearly half of fatalities due to weather were related to convective weather in the 1992-1994 timeframe, with lightning causing a large component of the fatalities, in addition to tornadoes and flash flooding. Related to the aviation industry, CG lightning represents a considerable hazard to baggage-handlers, aircraft refuelers, food caterers, and emergency personnel, who all become exposed to the risk of being struck within short time periods while convective storm clouds develop. Airport safety protocols require that ramp operations be modified or discontinued when lightning is in the vicinity (typically 16 km), which becomes very costly and disruptive to flight operations. Therefore, much focus has been paid to nowcasting the first-time initiation and extent of lightning, both of CG and of any lightning (e.g, in-cloud, cloud-to-cloud). For this project three lightning nowcasting methodologies will be combined: (1) a GOESbased 0-1 hour lightning initiation (LI) product (Harris et al. 2010; Iskenderian et al. 2012), (2) a High Resolution Rapid Refresh (HRRR) lightning probability and forecasted lightning flash density product, such that a quantitative amount of lightning (QL) can be assigned to a location of expected LI, and (3) an algorithm that relates Pseudo-GLM data (Stano et al. 2012, 2014) to the so-called "lightning jump" (LJ) methodology (Shultz et al

  17. The 1996 Paso del Norte Ozone Study: analysis of meteorological and air quality data that influence local ozone concentrations.

    PubMed

    MacDonal, C P; Roberts, P T; Main, H H; Dye, T S; Coe, D L; Yarbrough, J

    2001-08-10

    The 1996 Paso del Norte Ozone Study and subsequent data analyses were implemented to develop an understanding of the chemical and physical processes which lead to high concentrations of ozone in the Paso del Norte study area which includes El Paso County, Texas, Sunland Park, New Mexico, and Ciudad Juárez, Mexico. Both the data and data analysis results are being used to support photochemical grid modeling. El Paso County and Sunland Park fail to meet the National Ambient Air Quality Standard (NAAQS) for ozone, and neighboring Ciudad Juárez fails to meet the Mexican ambient standard for ozone. This paper summarizes the measurement campaigns of the 1996 Paso del Norte Ozone Study and the findings and conclusions that arose from subsequent data analyses. Data analyses showed that high ozone concentrations resulted from a combination of conditions, including high surface temperatures, strong sunlight with few clouds, light surface winds and high concentrations of ozone precursors at ground level in the morning, and slow convective boundary layer (CBL) growth. Synoptic-scale meteorological conditions observed during high ozone episodes included an aloft high-pressure system and aloft warming. Aloft carryover of ozone and ozone precursors did not significantly contribute to high concentrations of ozone at the surface.

  18. Antarctic Ozone Hole, 2000

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Each spring the ozone layer over Antarctica nearly disappears, forming a 'hole' over the entire continent. The hole is created by the interaction of some man-made chemicals-freon, for example-with Antarctica's unique weather patterns and extremely cold temperatures. Ozone in the stratosphere absorbs ultraviolet radiation from the sun, thereby protecting living things. Since the ozone hole was discovered many of the chemicals that destroy ozone have been banned, but they will remain in the atmosphere for decades. In 2000, the ozone hole grew quicker than usual and exceptionally large. By the first week in September the hole was the largest ever-11.4 million square miles. The top image shows the average total column ozone values over Antarctica for September 2000. (Total column ozone is the amount of ozone from the ground to the top of the atmosphere. A relatively typical measurement of 300 Dobson Units is equivalent to a layer of ozone 0.12 inches thick on the Earth's surface. Levels below 220 Dobson Units are considered to be significant ozone depletion.) The record-breaking hole is likely the result of lower than average ozone levels during the Antarctic fall and winter, and exceptionally cold temperatures. In October, however (bottom image), the hole shrank dramatically, much more quickly than usual. By the end of October, the hole was only one-third of it's previous size. In a typical year, the ozone hole does not collapse until the end of November. NASA scientists were surprised by this early shrinking and speculate it is related to the region's weather. Global ozone levels are measured by the Total Ozone Mapping Spectrometer (TOMS). For more information about ozone, read the Earth Observatory's ozone fact sheet, view global ozone data and see these ozone images. Images by Greg Shirah, NASA GSFC Scientific Visualization Studio.

  19. Children's and adults' knowledge and models of reasoning about the ozone layer and its depletion

    NASA Astrophysics Data System (ADS)

    Leighton, Jacqueline P.; Bisanz, Gay L.

    2003-01-01

    As environmental concepts, the ozone layer and ozone hole are important to understand because they can profoundly influence our health. In this paper, we examined: (a) children's and adults' knowledge of the ozone layer and its depletion, and whether this knowledge increases with age' and (b) how the 'ozone layer' and 'ozone hole' might be structured as scientific concepts. We generated a standardized set of questions and used it to interview 24 kindergarten students, 48 Grade 3 students, 24 Grade 5 students, and 24 adults in university, in Canada. An analysis of participants' responses revealed that adults have more knowledge than children about the ozone layer and ozone hole, but both adults and children exhibit little knowledge about protecting themselves from the ozone hole. Moreover, only some participants exhibited 'mental models' in their conceptual understanding of the ozone layer and ozone hole. The implications of these results for health professionals, educators, and scientists are discussed.

  20. Plasmadynamic ozone generator

    NASA Astrophysics Data System (ADS)

    Gordeev, Yu. N.; Ogurechnikov, V. A.; Chizhov, Yu. L.

    2009-10-01

    The formation of ozone in a low-temperature supersonic flow of a mixture of air and partly dissociated oxygen supplied from a discharge plasmatron has been experimentally studied. For an oxygen mass fraction of 1.1% in the total gas flow supplied to this ozone generator, an ozone-air mixture containing 4.88 × 10-3 kg/m3 ozone is obtained at a specific energy consumption of 25.8 MJ/(kg ozone). In this regime, the ozone generator could operate for several dozen minutes.

  1. The Antarctic ozone hole

    NASA Astrophysics Data System (ADS)

    Jones, Anna E.

    2008-07-01

    Since the mid 1970s, the ozone layer over Antarctica has experienced massive destruction during every spring. In this article, we will consider the atmosphere, and what ozone and the ozone layer actually are. We explore the chemistry responsible for the ozone destruction, and learn about why conditions favour ozone destruction over Antarctica. For the historical perspective, the events leading up to the discovery of the 'hole' are presented, as well as the response from the international community and the measures taken to protect the ozone layer now and into the future.

  2. Tropospheric Ozone and Photochemical Smog

    NASA Astrophysics Data System (ADS)

    Sillman, S.

    2003-12-01

    emitted species, in a process that is driven by sunlight and is accelerated by warm temperatures. This smog is largely the product of gasoline-powered engines (especially automobiles), although coal-fired industry can also generate photochemical smog. The process of photochemical smog formation was first identified by Haagen-Smit and Fox (1954) in association with Los Angeles, a city whose geography makes it particularly susceptible to this type of smog formation. Sulfate aerosols and organic particulates are often produced concurrently with ozone, giving rise to a characteristic milky-white haze associated with this type of air pollution.Today ozone and particulates are recognized as the air pollutants that are most likely to affect human health adversely. In the United States, most major metropolitan areas have periodic air pollution events with ozone in excess of government health standards. Violations of local health standards also occur in major cities in Canada and in much of Europe. Other cities around the world (especially Mexico City) also experience very high ozone levels. In addition to urban-scale events, elevated ozone occurs in region-wide events in the eastern USA and in Western Europe, with excess ozone extending over areas of 1,000 km2 or more. Ozone plumes of similar extent are found in the tropics (especially in Central Africa) at times of high biomass burning (e.g., Jenkins et al., 1997; Chatfield et al., 1998). In some cases ozone associated with biomass burning has been identified at distances up to 104 km from its sources (Schultz et al., 1999).Ozone also has a significant impact on the global troposphere, and ozone chemistry is a major component of global tropospheric chemistry. Global background ozone concentrations are much lower than urban or regional concentrations during pollution events, but there is evidence that the global background has increased as a result of human activities (e.g., Wang and Jacob, 1998; Volz and Kley, 1988). A rise in

  3. Basic Ozone Layer Science

    EPA Pesticide Factsheets

    Learn about the ozone layer and how human activities deplete it. This page provides information on the chemical processes that lead to ozone layer depletion, and scientists' efforts to understand them.

  4. Surface Ozone evolution in Coastal Continental Antarctica

    NASA Astrophysics Data System (ADS)

    Navarro-Comas, M.; Yela, M.; Gil, M.; Parrondo, M. C.; Ochoa, H.

    2009-04-01

    Surface ozone measurements from two complete years (February 2007 to February 2009) at Belgrano station (Antarctica, 78°S, 35°W) are presented. Belgrano is a coastal station lying approximately 20 km from the Weddell Sea coast and located 256 m above sea level. A UV photometric ozone analyzer, model TEI 49C, was deployed with the double purpose of, in the first place, perform the quality control of ozonesounding before launching and, on second place, background ozone monitoring in a long term basis. The two years data analysis shows an annual ozone cycle with one month lag on surface ozone data and the solstices. The ozone maximum is reached in mid-winter (in July), while the minimum is attained in summer (in January) in opposition of typical mid-latitude continental observatories, but in agreement with other coastal observatories in Antarctica. The daily mean maximum observed during the whole period peaks at 36.5 ppbv in July and the minimum value observed was found to be 6.9 ppbv, in December. The mean surface ozone concentration value calculated during the observational period was 24.3 ppbv with a standard deviation of 7.7 ppbv. The fast transition night to day that takes place in Belgrano does not correlate with the seasonal ozone distribution suggesting that distribution may be controlled by transport mechanisms with a minor contribution of the photochemistry. It is also observed a higher day to day variation after the polar night, during the Antarctic spring and summer. Several depleted ozone events have been found along the observational period during the Austral spring (October-December) season, attributable to photochemical catalyzed ozone depletion from halogen chemistry. During those days, the ozone mixing ration drops until only a few ppbv in a short period of time (within a few hours). BrO observation from the satellite instrument SCIAMACHY shows large patterns of enhancements of BrO in the Weddell Sea during those days and calculated HYSPLIT

  5. [Analysis on prevalence of physical activity time <1 hour and related factors in students aged 9-22 years in China, 2014].

    PubMed

    Wang, Z H; Dong, Y H; Song, Y; Yang, Z P; Ma, J

    2017-03-10

    Objective: To explore the prevalence of physical activity time <1 hour and related factors in students aged 9-22 years in China. Methods: A total of 220 159 students (110 039 boys and 110 120 girls) aged 9-22 years who completed the questionnaire of physical activity and lifestyle behaviors were selected from " 2014 National Physical Fitness and Health Surveillance" for the current study. All the participants were divided into 2 groups, i.e. physical activity time <1 hour and physical activity time ≥1 hour according the suggestion of Central Government, stratified by age and gender. χ(2) tests were used to compare the difference in the prevalence of physical activity time <1 hour between boys and girls in every age groups. Univariate and multivariate log-binomial regression models were used to explore the factors that influenced the prevalence of physical activity time <1 hour. Results: The boy's prevalence of physical activity time <1 hour was 73.3%, with the lowest (57.0%) in 9-years-old group, and highest (82.5%) in 18 years old group. The girl's prevalence of physical activity time <1 hour was 79.1%, with the lowest (60.1%) in 9-years-old group, and highest (89.8%) in 21 years old group. Overall, The prevalence of physical activity time <1 hour was significantly higher in girls than in boys (P<0.001), and the prevalence were significantly higher in girls than in boys in all the age groups (P<0.001), and it was observed that the prevalence of physical activity <1 hour increased with age in both boys and girls (P<0.001). Multivariate log-binomial regression model found that being girl (PR=1.05, 95%CI: 1.05-1.06), parents' disliking children to participate physical activity (PR=1.08, 95% CI: 1.07-1.09), heavy homework (PR=1.13, 95% CI: 1.12-1.14), long homework time (PR =1.08, 95%CI: 1.07-1.08), long time spending on electronic screen watching (PR=1.01, 95%CI: 1.00-1.01) and disliking physical class (PR=1.11, 95%CI: 1.10-1.12) could be the risk factors for

  6. Effect of Ventilation Strategies on Residential Ozone Levels

    SciTech Connect

    Walker, Iain S.; Sherman, Max H.

    2012-08-01

    Elevated outdoor ozone levels are associated with adverse health effects. Because people spend the vast majority of their time indoors, reduction in indoor levels of ozone of outdoor origin would lower population exposures and might also lead to a reduction in ozone-associated adverse health effects. In most buildings, indoor ozone levels are diminished with respect to outdoor levels to an extent that depends on surface reactions and on the degree to which ozone penetrates the building envelope. Ozone enters buildings from outdoors together with the airflows that are driven by natural and mechanical means, including deliberate ventilation used to reduce concentrations of indoor-generated pollutants. When assessing the effect of deliberate ventilation on occupant health one should consider not only the positive effects on removing pollutants of indoor origin but also the possibility that enhanced ventilation might increase indoor levels of pollutants originating outdoors. This study considers how changes in residential ventilation that are designed to comply with ASHRAE Standard 62.2 might influence indoor levels of ozone. Simulation results show that the building envelope can contribute significantly to filtration of ozone. Consequently, the use of exhaust ventilation systems is predicted to produce lower indoor ozone concentrations than would occur with balanced ventilation systems operating at the same air-­exchange rate. We also investigated a strategy for reducing exposure to ozone that would deliberately reduce ventilation rates during times of high outdoor ozone concentration while still meeting daily average ventilation requirements.

  7. Airliner cabin ozone: An updated review. Final report

    SciTech Connect

    Melton, C.E.

    1989-12-01

    The recent literature pertaining to ozone contamination of airliner cabins is reviewed. Measurements in airliner cabins without filters showed that ozone levels were about 50 percent of atmospheric ozone. Filters were about 90 percent effective in destroying ozone. Ozone (0.12 to 0.14 ppmv) caused mild subjective respiratory irritation in exercising men, but 0.20 to 0.30 ppmv did not have adverse effects on patients with chronic heart or lung disease. Ozone (1.0 to 2.0 ppmv) decreased survival time of influenza-infected rats and mice and suppressed the capacity of lung macrophages to destroy Listeria. Airway responses to ozone are divided into an early parasympathetically mediated bronchoconstrictive phase and a later histamine-mediated congestive phase. Evidence indicates that intracellular free radicals are responsible for ozone damage and that the damage may be spread to other cells by toxic intermediate products: Antioxidants provide some protection to cells in vitro from ozone but dietary intake of antioxidant vitamins by humans has only a weak effect, if any. This review indicates that earlier findings regarding ozone toxicity do not need to be corrected. Compliance with existing FAA ozone standards appears to provide adequate protection to aircrews and passengers.

  8. Ozone Trend Detectability

    NASA Technical Reports Server (NTRS)

    Campbell, J. W. (Editor)

    1981-01-01

    The detection of anthropogenic disturbances in the Earth's ozone layer was studied. Two topics were addressed: (1) the level at which a trend in total ozoning is detected by existing data sources; and (2) empirical evidence in the prediction of the depletion in total ozone. Error sources are identified. The predictability of climatological series, whether empirical models can be trusted, and how errors in the Dobson total ozone data impact trend detectability, are discussed.

  9. Ozone Layer Observations

    NASA Technical Reports Server (NTRS)

    McPeters, Richard; Bhartia, P. K. (Technical Monitor)

    2002-01-01

    The US National Aeronautics and Space Administration (NASA) has been monitoring the ozone layer from space using optical remote sensing techniques since 1970. With concern over catalytic destruction of ozone (mid-1970s) and the development of the Antarctic ozone hole (mid-1980s), long term ozone monitoring has become the primary focus of NASA's series of ozone measuring instruments. A series of TOMS (Total Ozone Mapping Spectrometer) and SBUV (Solar Backscatter Ultraviolet) instruments has produced a nearly continuous record of global ozone from 1979 to the present. These instruments infer ozone by measuring sunlight backscattered from the atmosphere in the ultraviolet through differential absorption. These measurements have documented a 15 Dobson Unit drop in global average ozone since 1980, and the declines in ozone in the antarctic each October have been far more dramatic. Instruments that measure the ozone vertical distribution, the SBUV and SAGE (Stratospheric Aerosol and Gas Experiment) instruments for example, show that the largest changes are occurring in the lower stratosphere and upper troposphere. The goal of ozone measurement in the next decades will be to document the predicted recovery of the ozone layer as CFC (chlorofluorocarbon) levels decline. This will require a continuation of global measurements of total column ozone on a global basis, but using data from successor instruments to TOMS. Hyperspectral instruments capable of measuring in the UV will be needed for this purpose. Establishing the relative roles of chemistry and dynamics will require instruments to measure ozone in the troposphere and in the stratosphere with good vertical resolution. Instruments that can measure other chemicals important to ozone formation and destruction will also be needed.

  10. Ozone columns obtained by ground-based remote sensing in Kiev for Aura Ozone Measuring Instrument validation

    NASA Astrophysics Data System (ADS)

    Shavrina, A. V.; Pavlenko, Y. V.; Veles, A.; Syniavskyi, I.; Kroon, M.

    2007-12-01

    Ground-based observations with a Fourier transform spectrometer in the infrared region (FTIR) were performed in Kiev (Ukraine) during the time frames August-October 2005 and June-October 2006 within the Ozone Monitoring Instrument (OMI) validation project 2907 entitled "OMI validation by ground based remote sensing: ozone columns and profiles" in the frame of the international European Space Agency/Netherlands Agency for Aerospace Programmes/Royal Dutch Meteorological Institute OMI Announcement of Opportunity effort. Ozone column data for 2005 were obtained by modeling the ozone spectral band at 9.6 μm with the radiative transfer code MODTRAN3.5. Our total ozone column values were found to be lower than OMI Differential Optical Absorption Spectroscopy (DOAS) total ozone column data by 8-10 Dobson units (DU, 1 DU = 0.001 atm cm) on average, while our observations have a relatively small standard error of about 2 DU. Improved modeling of the ozone spectral band, now based on HITRAN-2004 spectral data as calculated by us, moves our results toward better agreement with the OMI DOAS total ozone column data. The observations made during 2006 with a modernized FTIR spectrometer and higher signal-to-noise ratio were simulated by the MODTRAN4 model computations. For ozone column estimates the Aqua Atmospheric Infrared Sounder satellite water vapor and temperature profiles were combined with the Aura Microwave Limb Sounder stratospheric ozone profiles and Tropospheric Emission Monitoring Internet Service-Koninklijk Nederlands Meteorologisch Instituut climatological profiles to create a priori input files for spectral modeling. The MODTRAN4 estimates of ozone columns from the 2006 observations compare rather well with the OMI total ozone column data: standard errors are of 1.11 DU and 0.68 DU, standard deviation are of 8.77 DU and 5.37 DU for OMI DOAS and OMI Total Ozone Mapping Spectrometer, respectively.

  11. Ozone drinking water treatment handbook

    SciTech Connect

    Rice, R.G.

    1990-01-01

    This book explains how ozone can be used to provide primary disinfection, while minimizing halogenated by-products. This is of use to those who design pilot plant studies in full scale ozone plants-and those who employ ozone and regulatory personnel. Detailed section on components of an ozonization system outlines feed gas preparation (air and oxygen), ozone generation, ozone contacting, ozone off gas destruction, monitoring and control of ozonation systems, engineering aspects of ozone, cost factors in ozone technology, case histories (European and U.S.).

  12. Ozone Antimicrobial Efficacy

    EPA Science Inventory

    Ozone is a potent germicide that has been used extensively for water purification. In Europe, 90 percent of the municipal water systems are treated with ozone, and in France, ozone has been used to treat drinking water since 1903. However, there is limited information on the bioc...

  13. Decadal Changes in Ozone and Emissions in Central California and Current Issues

    NASA Astrophysics Data System (ADS)

    Tanrikulu, S.; Beaver, S.; Soong, S.; Tran, C.; Cordova, J.; Palazoglu, A.

    2011-12-01

    The relationships among ozone, emissions, and meteorology are very complex in central California, and must be well studied and understood in order to facilitate better air quality planning. Factors significantly impacting changes in emissions such as economic and population growth, and adopted emission controls make the matter even more complex. Here we review the history of ozone pollution in central California since the 1970s to plan for the future. Since the 1970s, changes in emissions have been accompanied by likewise dramatic changes in region-to-region differences in air quality. We focus on the coastal San Francisco Bay Area (SFBA) and the inland San Joaquin Valley (SJV). In the 1970s, the SFBA population was approaching 5 million people while the considerably larger and more rural SJV population remained below 2 million. The SFBA population was mostly confined to coastal locations. Peak ozone levels occurred mostly around the population centers and especially over the Bay itself. Hourly average ozone levels routinely approached 160 ppb. These high ozone levels promoted regulations under which SFBA emissions were continuously reduced through the present. By the 1990s, SFBA emissions had been reduced considerably despite the region's population growing to around 6 million. Relative to the 1970s, in 1990s the SFBA had lower peak ozone levels that were shifted to inland locations where much of the population growth was occurring. The SFBA still exceeded the federal 1-hour standard. A rapidly changing economic landscape in the 1970s promoted vast changes in the central California population distribution. In the SJV, the OPEC oil crisis promoted significant development of petroleum resources. Meanwhile, family farms were quickly being replaced with commercial-scale farming operations. The SJV population rapidly expanded to around 3 million people by the early 1990s. During this time, SJV emissions increased considerably, largely from increases in mobile source

  14. 40 CFR 60.1265 - How do I convert my 1-hour arithmetic averages into the appropriate averaging times and units?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... geometric average concentrations of sulfur dioxide emissions. If you are monitoring the percent reduction of... daily geometric average percent reduction of potential sulfur dioxide emissions. (c) If you operate a... Continuous Emission Monitoring § 60.1265 How do I convert my 1-hour arithmetic averages into the...

  15. Dynamic contrast-enhanced magnetic resonance imaging of osseous spine metastasis before and 1 hour after high-dose image-guided radiation therapy.

    PubMed

    Lis, Eric; Saha, Atin; Peck, Kyung K; Zatcky, Joan; Zelefsky, Michael J; Yamada, Yoshiya; Holodny, Andrei I; Bilsky, Mark H; Karimi, Sasan

    2017-01-01

    OBJECTIVE High-dose image-guided radiation therapy (HD IGRT) has been instrumental in mitigating some limitations of conventional RT. The recent emergence of dynamic contrast-enhanced (DCE) MRI to investigate tumor physiology can be used to verify the response of human tumors to HD IGRT. The purpose of this study was to evaluate the near-immediate effects of HD IGRT on spine metastases through the use of DCE MRI perfusion studies. METHODS Six patients with spine metastases from prostate, thyroid, and renal cell carcinoma who underwent HD IGRT were studied using DCE MRI prior to and 1 hour after HD IGRT. The DCE perfusion parameters plasma volume (Vp) and vascular permeability (Ktrans) were measured to assess the near-immediate and long-term tumor response. A Mann-Whitney U-test was performed to compare significant changes (at p ≤ 0.05) in perfusion parameters before and after RT. RESULTS The authors observed a precipitous drop in Vp within 1 hour of HD IGRT, with a mean decrease of 65.2%. A significant difference was found between Vp values for before and 1 hour after RT (p ≤ 0.05). No significant change was seen in Vp (p = 0.31) and Ktrans (p = 0.1) from 1 hour after RT to the first follow-up. CONCLUSIONS The data suggest that there is an immediate effect of HD IGRT on the vascularity of spine metastases, as demonstrated by a precipitous decrease in Vp. The DCE MRI studies can detect such changes within 1 hour after RT, and findings are concordant with existing animal models.

  16. Using Ozone Lidar to Investigate Sources of High Ozone Concentrations in the Western United States

    NASA Astrophysics Data System (ADS)

    Senff, C. J.; Langford, A. O.; Alvarez, R. J.; Brewer, Wm. A.; Banta, R. M.; Marchbanks, R. D.; Sandberg, S. P.; Weickmann, A. M.; Holloway, J. S.; Williams, E. J.

    2016-06-01

    We have used NOAA's Tunable Optical Profiler for Aerosol and oZone (TOPAZ) ozone lidar to investigate the sources of high surface ozone concentrations in two different regions of the western United States (US): the Uintah Basin in northeast Utah and Clark County in southern Nevada, which includes the city of Las Vegas. The Uintah Basin is a booming oil and gas producing region that often suffers from very high wintertime ozone concentrations. Clark County experiences violations of the US ozone standard primarily in spring and early summer despite a lack of any major local pollution sources. TOPAZ lidar observations, in conjunction with surface in situ measurements and model results, provided strong evidence that the high wintertime ozone concentrations in the Uintah Basin are primarily driven by local emissions associated with oil and gas exploration, whereas the Clark County ozone exceedances are often caused by ozone-rich air that is transported from the lower stratosphere all the way down to the earth's surface.

  17. Tropospheric Ozone Pollution from Space: New Views from the TOMS (Total Ozone Mapping Spectrometer) Instrument

    NASA Technical Reports Server (NTRS)

    Thompson, Anne M.; Hudson, Robert D.; Frolov, Alexander D.; Witte, Jacquelyn C.; Kucsera, Tom L.; Einaudi, Franco (Technical Monitor)

    2000-01-01

    New products from the TOMS (Total Ozone Mapping Spectrometer) >satellite instrument can resolve pollution events in tropical and mid-latitudes, Over the past several years, we have developed tropospheric ozone data sets by two methods. The modified-residual technique [Hudson and Thompson, 1998; Thompson and Hudson, 1999] uses v. 7 TOMS total ozone and is applicable to tropical regimes in which the wave-one pattern in total ozone is observed. The TOMSdirect method [Hudson et at., 2000] represents a new algorithm that uses TOMS radiances to extract tropospheric ozone in regions of constant stratospheric ozone and tropospheric ozone displaying high mixing ratios and variability characteristic of pollution, Absorbing aerosols (dust and smoke; Herman et at., 1997 Hsu et al., 1999), a standard TOMS product, provide transport and/or source marker information to interpret tropospheric ozone. For the Nimbus 7/TOMS observing period (1979-1992), modified-residual TTO (tropical tropospheric ozone) appears as two maps/month at I-degree latitude 2-degree longitude resolution at a homepage and digital data are available (20S to 20N) by ftp at http://metosrv2. umd.edu/tropo/ 14y_data.d. Preliminary modified-residual TTO data from the operational Earth-Probe/TOMS (1996- present) are posted in near-real-time at the same website. Analyses with the new tropospheric ozone and aerosol data are illustrated by the following (I)Signals in tropical tropospheric ozone column and smoke amount during ENSO (El Nino-Southern Oscillation) events, e.g. 1982-1983 and the intense ENSO induced biomass fires of 1997-1998 over the Indonesian region [Thompson et a[, 2000a, Thompson and Hudson, 1999]. (2) Trends in tropospheric ozone and smoke aerosols in various tropical regions (Atlantic, Pacific, Africa, Brazil). No significant trends were found for ozone from1980-1990 [Thompson and Hudson, 19991 although smoke aerosols increased during the period [Hsu et al.,1999]. (3) Temporal and spatial offsets

  18. Efficacy and Safety of 1-Hour Infusion of Recombinant Human Atrial Natriuretic Peptide in Patients With Acute Decompensated Heart Failure

    PubMed Central

    Wang, Guogan; Wang, Pengbo; Li, Yishi; Liu, Wenxian; Bai, Shugong; Zhen, Yang; Li, Dongye; Yang, Ping; Chen, Yu; Hong, Lang; Sun, Jianhui; Chen, Junzhu; Wang, Xian; Zhu, Jihong; Hu, Dayi; Li, Huimin; Wu, Tongguo; Huang, Jie; Tan, Huiqiong; Zhang, Jian; Liao, Zhongkai; Yu, Litian; Mao, Yi; Ye, Shaodong; Feng, Lei; Hua, Yihong; Ni, Xinhai; Zhang, Yuhui; Wang, Yang; Li, Wei; Luan, Xiaojun; Sun, Xiaolu; Wang, Sijia

    2016-01-01

    Abstract The aim of the study was to evaluate the efficacy and safety of 1-h infusion of recombinant human atrial natriuretic peptide (rhANP) in combination with standard therapy in patients with acute decompensated heart failure (ADHF). This was a phase III, randomized, double-blind, placebo-controlled, multicenter trial. Eligible patients with ADHF were randomized to receive a 1-h infusion of either rhANP or placebo at a ratio of 3:1 in combination with standard therapy. The primary endpoint was dyspnea improvement (a decrease of at least 2 grades of dyspnea severity at 12 h from baseline). Reduction in pulmonary capillary wedge pressure (PCWP) 1 h after infusion was the co-primary endpoint for catheterized patients. Overall, 477 patients were randomized: 358 (93 catheterized) patients received rhANP and 118 (28 catheterized) received placebo. The percentage of patients with dyspnea improvement at 12 h was higher, although not statistically significant, in the rhANP group than in the placebo group (32.0% vs 25.4%, odds ratio=1.382, 95% confidence interval [CI]: 0.863–2.212, P = 0.17). Reduction in PCWP at 1 h was significantly greater in patients treated with rhANP than in patients treated with placebo (−7.74 ± 5.95 vs −1.82 ± 4.47 mm Hg, P < 0.001). The frequencies of adverse events and renal impairment within 3 days of treatment were similar between the 2 groups. Mortality at 1 month was 3.1% in the rhANP group vs 2.5% in the placebo group (hazard ratio = 1.21, 95% CI: 0.34–4.26; P > 0.99). 1-h rhANP infusion appears to result in prompt, transient hemodynamic improvement with a small, nonsignificant, effect on dyspnea in ADHF patients receiving standard therapy. The safety of 1-h infusion of rhANP seems to be acceptable. (WHO International Clinical Trials Registry Platform [ICTRP] number, ChiCTR-IPR-14005719.) PMID:26945407

  19. Rocket Ozone Data Recovery for Digital Archival

    NASA Astrophysics Data System (ADS)

    Hwang, S. H.; Krueger, A. J.; Hilsenrath, E.; Haffner, D. P.; Bhartia, P. K.

    2014-12-01

    Ozone distributions in the photochemically-controlled upper stratosphere and mesosphere were first measured using spectrometers on V-2 rockets after WWII. The IGY(1957-1958) spurred development of new optical and chemical instruments for flight on meteorological and sounding rockets. In the early 1960's, the US Navy developed an Arcas rocket-borne optical ozonesonde and NASA GSFC developed chemiluminescent ozonesonde onboard Nike_Cajun and Arcas rocket. The Navy optical ozone program was moved in 1969 to GSFC where rocket ozone research was expanded and continued until 1994 using Super Loki-Dart rocket at 11 sites in the range of 0-65N and 35W-160W. Over 300 optical ozone soundings and 40 chemiluminescent soundings were made. The data have been used to produce the US Standard Ozone Atmosphere, determine seasonal and diurnal variations, and validate early photochemical models. The current effort includes soundings conducted by Australia, Japan, and Korea using optical techniques. New satellite ozone sounding techniques were initially calibrated and later validated using the rocket ozone data. As satellite techniques superseded the rocket methods, the sponsoring agencies lost interest in the data and many of those records have been discarded. The current task intends to recover as much of the data as possible from the private records of the experimenters and their publications, and to archive those records in the WOUDC (World Ozone and Ultraviolet Data Centre). The original data records are handwritten tabulations, computer printouts that are scanned with OCR techniques, and plots digitized from publications. This newly recovered digital rocket ozone profile data from 1965 to 2002 could make significant contributions to the Earth science community in atmospheric research including long-term trend analysis.

  20. Overview of ozone bleaching

    SciTech Connect

    Sonnenberg, L.B.

    1995-12-31

    The potential impact of the pulp and paper industry on the environment may be reduced by replacing chlorine-based bleaching reagents with ozone. The reactivity of ozone coupled with the heterogeneity of pulp allows many types of reactions to occur during pulp bleaching. Ozone cleaves the aromatic rings and side chain double bonds in lignin in Criegee-type mechanisms. Activated carbon-hydrogen bonds are fragmented in lignin side chains, as well as Cl carbons of {beta}-glycosides, by way of a 1,3 dipolar insertion forming a hydrotrioxide intermediate. Ozone also attacks carbohydrates at acetal oxygens, depolymerizing at the glycosidic bond. Unsaturated sites are ozonated before aliphatic sites resulting in a predominance of lignin reactions over carbohydrate reactions until lignin is substantially removed from the pulp. Important factors in the successful application of ozone bleaching include minimizing ozone decomposition and other secondary reactions, reducing exposure of cellulose to high concentrations of ozone and radicals, and promoting uniform exposure of ozone to lignin. The quantity of chlorinated organic compounds in effluents can be drastically reduced by replacing chlorine-based bleaching reagents with ozone; less organochlorine is formed and there can be greater recycle of bleach plant wastes back to the recovery cycle. Recycling of bleach plant waste also reduces total organic loading in the effluent. The toxicity of ozone filtrates is variable compared to conventional filtrates and depends on several parameters including bleaching conditions, biological treatment, and target organisms.

  1. Spring polar ozone behavior

    NASA Technical Reports Server (NTRS)

    Aikin, Arthur C.

    1992-01-01

    Understanding of the springtime behavior of polar stratospheric ozone as of mid 1990 is summarized. Heterogeneous reactions on polar stratospheric clouds as hypothesis for ozone loss are considered and a simplified description of the behavior of Antarctic ozone in winter and spring is given. Evidence that the situation is more complicated than described by the theory is produced. Many unresolved scientific issues remain and some of the most important problems are identified. Ozone changes each spring since 1979 have clearly established for the first time that man made chlorine compounds influence stratospheric ozone. Long before important advances in satellite and in situ investigations, it was Dobson's decision to place a total ozone measuring spectrometer at Halley Bay in Antarctica during the International Geophysical Year and subsequent continuous monitoring which led to the discovery that ozone was being destroyed each spring by chlorine processed by polar stratospheric clouds.

  2. Ozone and the stratosphere

    NASA Technical Reports Server (NTRS)

    Shimazaki, Tatsuo

    1987-01-01

    It is shown that the stratospheric ozone is effective in absorbing almost all radiation below 300 nm at heights below 300 km. The distribution of global ozone in the troposphere and the lower stratosphere, and the latitudinal variations of the total ozone column over four seasons are considered. The theory of the ozone layer production is discussed together with catalytic reactions for ozone loss and the mechanisms of ozone transport. Special attention is given to the anthropogenic perturbations, such as SST exhaust gases and freon gas from aerosol cans and refrigerators, that may cause an extensive destruction of the stratospheric ozone layer and thus have a profound impact on the world climate and on life.

  3. On the "ozone deficit problem": what are Ox and HOx catalytic cycles for ozone depletion hiding?

    PubMed

    Varandas, António J C

    2002-05-17

    Studies on the role of vibrational excitation in the reactants for the O2 + O2, OH + O2, and HO2 + O2 reactions show that they can be important sources of ozone in the stratosphere, particularly at conditions of local thermodynamic disequilibrium. The results suggest that the Ox and HOx cycles commonly viewed as catalytic sinks of ozone may actually lead to its production, and hence help to clarify the "ozone deficit problem". This paper also presents an explanation for the general overestimation of the OH abundance in the upper stratosphere and lower mesosphere through standard HOx chemistry.

  4. Probabilistic aspects of meteorological and ozone regional ensemble forecasts

    SciTech Connect

    Monache, L D; Hacker, J; Zhou, Y; Deng, X; Stull, R

    2006-03-20

    This study investigates whether probabilistic ozone forecasts from an ensemble can be made with skill; i.e., high verification resolution and reliability. Twenty-eight ozone forecasts were generated over the Lower Fraser Valley, British Columbia, Canada, for the 5-day period 11-15 August 2004, and compared with 1-hour averaged measurements of ozone concentrations at five stations. The forecasts were obtained by driving the CMAQ model with four meteorological forecasts and seven emission scenarios: a control run, {+-} 50% NO{sub x}, {+-} 50% VOC, and {+-} 50% NO{sub x} combined with VOC. Probabilistic forecast quality is verified using relative operating characteristic curves, Talagrand diagrams, and a new reliability index. Results show that both meteorology and emission perturbations are needed to have a skillful probabilistic forecast system--the meteorology perturbation is important to capture the ozone temporal and spatial distribution, and the emission perturbation is needed to span the range of ozone-concentration magnitudes. Emission perturbations are more important than meteorology perturbations for capturing the likelihood of high ozone concentrations. Perturbations involving NO{sub x} resulted in a more skillful probabilistic forecast for the episode analyzed, and therefore the 50% perturbation values appears to span much of the emission uncertainty for this case. All of the ensembles analyzed show a high ozone concentration bias in the Talagrand diagrams, even when the biases from the unperturbed emissions forecasts are removed from all ensemble members. This result indicates nonlinearity in the ensemble, which arises from both ozone chemistry and its interaction with input from particular meteorological models.

  5. Probabilistic aspects of meteorological and ozone regional ensemble forecasts

    NASA Astrophysics Data System (ADS)

    Delle Monache, Luca; Hacker, Joshua P.; Zhou, Yongmei; Deng, Xingxiu; Stull, Roland B.

    2006-12-01

    This study investigates whether probabilistic ozone forecasts from an ensemble can be made with skill: i.e., high verification resolution and reliability. Twenty-eight ozone forecasts were generated over the Lower Fraser Valley, British Columbia, Canada, for the 5-day period 11-15 August 2004 and compared with 1-hour averaged measurements of ozone concentrations at five stations. The forecasts were obtained by driving the Community Multiscale Air Quality Model (CMAQ) model with four meteorological forecasts and seven emission scenarios: a control run, ±50% NOx, ±50% volatile organic compounds (VOC), and ±50% NOx combined with VOC. Probabilistic forecast quality is verified using relative operating characteristic curves, Talagrand diagrams, and a new reliability index. Results show that both meteorology and emission perturbations are needed to have a skillful probabilistic forecast system: the meteorology perturbation is important to capture the ozone temporal and spatial distribution and the emission perturbation is needed to span the range of ozone concentration magnitudes. Emission perturbations are more important than meteorology perturbations for capturing the likelihood of high ozone concentrations. Perturbations involving NOx resulted in a more skillful probabilistic forecast for the episode analyzed, and therefore the 50% perturbation values appear to span much of the emission uncertainty for this case. All of the ensembles analyzed show a high ozone concentration bias in the Talagrand diagrams, even when the biases from the unperturbed emissions forecasts are removed from all ensemble members. This result indicates nonlinearity in the ensemble, which arises from both ozone chemistry and its interaction with input from particular meteorological models.

  6. Multi-Model Comparison of Lateral Boundary Contributions to Surface Ozone Over the United States

    EPA Science Inventory

    As the National Ambient Air Quality Standards (NAAQS) for ozone become more stringent, there has been growing attention on characterizing the contributions and the uncertainties in ozone from outside the US to the ozone concentrations within the US. The third phase of the Air Qua...

  7. Multi-model Comparison of Lateral Boundary Contributions to Ozone Concentrations over the United States (CM

    EPA Science Inventory

    As the National Ambient Air Quality Standards (NAAQS) for ozone become more stringent, there has been growing attention on characterizing the contributions and the uncertainties in ozone from outside the US to the ozone concentrations within the US. The third phase of the Air Qua...

  8. 76 FR 54412 - Determination of Nonattainment and Reclassification of the Baltimore 1997 8-Hour Ozone...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-01

    ... Ozone Nonattainment Area; MD AGENCY: Environmental Protection Agency (EPA). ACTION: Proposed rule. SUMMARY: EPA is proposing to determine that the Baltimore moderate 8- hour ozone nonattainment area (the Baltimore Area) did not attain the 1997 8-hour ozone national ambient air quality standard (NAAQS) by...

  9. Multi-model Comparison of Lateral Boundary Contributions to Ozone Concentrations over the United States

    EPA Science Inventory

    As the National Ambient Air Quality Standards (NAAQS) for ozone become more stringent, there has been growing attention on characterizing the contributions and the uncertainties in ozone from outside the US to the ozone concentrations within the US. The third phase of the Air Qua...

  10. 77 FR 13974 - Approval and Promulgation of Implementation Plans; New York State Ozone Implementation Plan Revision

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-08

    ... AGENCY 40 CFR Part 52 Approval and Promulgation of Implementation Plans; New York State Ozone... (SIP) for ozone concerning the control of volatile organic compounds. The proposed SIP revision... will help attain and maintain the national ambient air quality standards for ozone. DATES:...

  11. 78 FR 9596 - Approval and Promulgation of Implementation Plans; New Jersey and New York Ozone Attainment...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-11

    ... AGENCY 40 CFR Part 52 Approval and Promulgation of Implementation Plans; New Jersey and New York Ozone... Environmental Protection Agency (EPA) is approving the ozone attainment demonstration portion of comprehensive... requirements for attaining the 1997 8-hour ozone national ambient air quality standard. EPA is approving...

  12. 76 FR 60820 - Draft Integrated Science Assessment for Ozone and Related Photochemical Oxidants

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-30

    ... AGENCY Draft Integrated Science Assessment for Ozone and Related Photochemical Oxidants AGENCY... titled, ``Second External Review Draft Integrated Science Assessment for Ozone and Related Photochemical... ambient air quality standards (NAAQS) for ozone. EPA is releasing this draft document to seek review...

  13. 77 FR 73570 - Approval and Promulgation of Implementation Plans; New Jersey and New York Ozone Attainment...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-11

    ...-0840, FRL-9761-7] Approval and Promulgation of Implementation Plans; New Jersey and New York Ozone... Environmental Protection Agency (EPA) is proposing action on the ozone attainment demonstration portion of... requirements for attaining the 1997 8-hour ozone national ambient air quality standard. EPA is proposing...

  14. 77 FR 36534 - Third External Review Draft Integrated Science Assessment for Ozone and Related Photochemical...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-19

    ... AGENCY Third External Review Draft Integrated Science Assessment for Ozone and Related Photochemical... External Review Draft Integrated Science Assessment for Ozone and Related Photochemical Oxidants'' (EPA/600... Standards (NAAQS) for ozone. EPA is releasing this draft document to seek review by the Clean Air...

  15. 76 FR 77178 - Approval and Promulgation of Implementation Plans; New York State Ozone Implementation Plan Revision

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-12

    ... AGENCY 40 CFR Part 52 Approval and Promulgation of Implementation Plans; New York State Ozone... Implementation Plan (SIP) for ozone concerning the control of volatile organic compounds. The proposed SIP... reductions that will help attain and maintain the national ambient air quality standards for ozone....

  16. 76 FR 10893 - Draft Integrated Science Assessment for Ozone and Related Photochemical Oxidants

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-28

    ... AGENCY Draft Integrated Science Assessment for Ozone and Related Photochemical Oxidants AGENCY... review draft of a document titled, ``First External Review Draft Integrated Science Assessment for Ozone... review of the national ambient air quality standards (NAAQS) for ozone. EPA is releasing this...

  17. Children's and Adults' Knowledge and Models of Reasoning about the Ozone Layer and Its Depletion.

    ERIC Educational Resources Information Center

    Leighton, Jacqueline P.; Bisanz, Gay L.

    2003-01-01

    Examines children's and adults' knowledge of the ozone layer and its depletion, whether this knowledge increases with age, and how the ozone layer and ozone hole might be structured as scientific concepts. Uses a standardized set of questions to interview children and adults in Canada. Discusses implications of the results for health…

  18. Integrated Science Assessment (ISA) of Ozone and Related ...

    EPA Pesticide Factsheets

    EPA has released the Integrated Science Assessment of Ozone and Related Photochemical Oxidants (Second External Review Draft) for independent peer review and public review. This draft document represents a concise synthesis and evaluation of the most policy-relevant science and will ultimately provide the scientific bases for EPA’s decision regarding the adequacy of the current national ambient air quality standards for ozone to protect human health, public welfare, and the environment. Critical evaluation and integration of the evidence on health and environmental effects of ozone to provide scientific support for the review of the NAAQS for ozone.

  19. Integrated Science Assessment (ISA) of Ozone and Related ...

    EPA Pesticide Factsheets

    EPA has released the Integrated Science Assessment of Ozone and Related Photochemical Oxidants (Third External Review Draft) for independent peer review and public review. This draft document represents a concise synthesis and evaluation of the most policy-relevant science and will ultimately provide the scientific bases for EPA’s decision regarding the adequacy of the current national ambient air quality standards for ozone to protect human health, public welfare, and the environment. Critical evaluation and integration of the evidence on health and environmental effects of ozone to provide scientific support for the review of the NAAQS for ozone.

  20. Integrated Science Assessment (ISA) of Ozone and Related ...

    EPA Pesticide Factsheets

    EPA announced that the First External Review Draft of the Integrated Science Assessment for Ozone and Related Photochemical Oxidants has been made available for independent peer review and public review. This draft document represents a concise synthesis and evaluation of the most policy-relevant science and will ultimately provide the scientific bases for EPA’s decision regarding the adequacy of the current national ambient air quality standards for ozone to protect human health, public welfare, and the environment. Critical evaluation and integration of the evidence on health and environmental effects of ozone to provide scientific support for the review of the NAAQS for ozone.

  1. 2013 Final Report: Integrated Science Assessment of Ozone ...

    EPA Pesticide Factsheets

    EPA is announcing the availability of the Integrated Science Assessment of Ozone and Related Photochemical Oxidants (Final Report). This document represents a concise synthesis and evaluation of the most policy-relevant science and will ultimately provide the scientific bases for EPA’s decision regarding the adequacy of the current national ambient air quality standards for ozone to protect human health, public welfare, and the environment. Critical evaluation and integration of the evidence on health and environmental effects of ozone to provide scientific support for the review of the NAAQS for ozone.

  2. Integrated Science Assessment (ISA) of Ozone and Related ...

    EPA Pesticide Factsheets

    EPA announced the availability of the final report, Integrated Science Assessment of Ozone and Related Photochemical Oxidants. This document represents a concise synthesis and evaluation of the most policy-relevant science and will ultimately provide the scientific bases for EPA’s decision regarding the adequacy of the current national ambient air quality standards for ozone to protect human health, public welfare, and the environment. Critical evaluation and integration of the evidence on health and environmental effects of ozone to provide scientific support for the review of the NAAQS for ozone.

  3. AIR QUALITY CRITERIA FOR OZONE AND RELATED PHOTOCHEMICAL OXIDANTS

    EPA Science Inventory

    The Clean Air Act requires periodic (5-year) update revision of criteria and National Ambient Air Quality Standards (NAAQS) for Ozone. The previous revision of the criteria contained in the Air Quality Criteria Document (AQCD) for Ozone and Related Photochemical Oxidants was co...

  4. Oxidation of polynuclear aromatic hydrocarbons in water. 1: Ozonation

    SciTech Connect

    Beltran, F.J.; Encinar, J.M.; Rivas, J.; Ovejero, G.

    1995-05-01

    The oxidation of three polynuclear aromatic hydrocarbons (PAHs), fluorene, phenanthrene, and acenaphthene, in aqueous solution with ozone has been studied. The influence of hydroxyl radical inhibitors, pH, ozone partial pressure, and temperature was investigated. All the PAHs studied show high oxidation rates with ozone. The ozonation of fluorene seems to be due to both direct and hydroxyl radical reactions while for the rest of the PAHs the ozonation develops only through direct reactions with ozone. Rate constants for the direct reaction between these PAHs and ozone have also been calculated. The reactivity with ozone goes in the following order: fluorene < phenanthrene < acenaphthene. The contribution of radical reactions represents more than 90% in the ozonation of fluorene in most cases except in the presence of hydroxyl radical inhibitors. In a standard agitated reactor the kinetic regime of the absorption of ozone corresponds to a slow reaction in the case of fluorene and phenanthrene and to a fast reaction in the case of acenaphthene.

  5. 40 CFR 96.306 - Standard requirements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... NOX Ozone Season Trading Program General Provisions § 96.306 Standard requirements. (a) Permit requirements. (1) The CAIR designated representative of each CAIR NOX Ozone Season source required to have a title V operating permit and each CAIR NOX Ozone Season unit required to have a title V operating...

  6. 40 CFR 96.306 - Standard requirements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... NOX Ozone Season Trading Program General Provisions § 96.306 Standard requirements. (a) Permit requirements. (1) The CAIR designated representative of each CAIR NOX Ozone Season source required to have a title V operating permit and each CAIR NOX Ozone Season unit required to have a title V operating...

  7. 40 CFR 96.306 - Standard requirements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... NOX Ozone Season Trading Program General Provisions § 96.306 Standard requirements. (a) Permit requirements. (1) The CAIR designated representative of each CAIR NOX Ozone Season source required to have a title V operating permit and each CAIR NOX Ozone Season unit required to have a title V operating...

  8. 40 CFR 96.306 - Standard requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... NOX Ozone Season Trading Program General Provisions § 96.306 Standard requirements. (a) Permit requirements. (1) The CAIR designated representative of each CAIR NOX Ozone Season source required to have a title V operating permit and each CAIR NOX Ozone Season unit required to have a title V operating...

  9. 40 CFR 96.306 - Standard requirements.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... NOX Ozone Season Trading Program General Provisions § 96.306 Standard requirements. (a) Permit requirements. (1) The CAIR designated representative of each CAIR NOX Ozone Season source required to have a title V operating permit and each CAIR NOX Ozone Season unit required to have a title V operating...

  10. 75 FR 80420 - Reasonable Further Progress Requirements for the 1997 8-Hour Ozone National Ambient Air Quality...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-22

    ... Ozone National Ambient Air Quality Standard AGENCY: Environmental Protection Agency (EPA). ACTION... 1997 8-hour ozone national ambient air quality standards (NAAQS). Specifically, EPA is proposing that... nitrogen oxides (NO X )] that contribute to ground-level ozone concentrations. B. What should I consider...

  11. Low-Dose-Rate Irradiation for 1 Hour Induces Protection Against Lethal Radiation Doses but Does Not Affect Life Span of DBA/2 Mice

    PubMed Central

    Altaner, Čestmír; Altanerova, Veronika; Ebbesen, Peter; Pettersen, Erik O.

    2016-01-01

    Prior findings showed that serum from DBA/2 mice that had been given whole-body irradiation for 1 hour at a low dose rate (LDR) of 30 cGy/h induced protection against radiation in reporter cells by a mechanism depending on transforming growth factor β3 and inducible nitric oxide synthase activity. In the present study, the effect of the 1 hour of LDR irradiation on the response of the preirradiated mice to a subsequent lethal dose and on the life span is examined. These DBA/2 mice were prime irradiated for 1 hour at 30 cGy/h. Two experiments with 9 and 9.5 Gy challenge doses given 6 weeks after priming showed increased survival in primed mice compared to unprimed mice followed up to 225 and 81 days after challenge irradiation, respectively. There was no overall significant difference in life span between primed and unprimed mice when no challenge irradiation was given. The males seemed to have a slight increase in lifespan after priming while the opposite was seen for the females. PMID:27867323

  12. Total ozone trend significance from space time variability of daily Dobson data

    NASA Technical Reports Server (NTRS)

    Wilcox, R. W.

    1981-01-01

    Estimates of standard errors of total ozone time and area means, as derived from ozone's natural temporal and spatial variability and autocorrelation in middle latitudes determined from daily Dobson data are presented. Assessing the significance of apparent total ozone trends is equivalent to assessing the standard error of the means. Standard errors of time averages depend on the temporal variability and correlation of the averaged parameter. Trend detectability is discussed, both for the present network and for satellite measurements.

  13. Ozone therapy in periodontics.

    PubMed

    Gupta, G; Mansi, B

    2012-02-22

    Gingival and Periodontal diseases represent a major concern both in dentistry and medicine. The majority of the contributing factors and causes in the etiology of these diseases are reduced or treated with ozone in all its application forms (gas, water, oil). The beneficial biological effects of ozone, its anti-microbial activity, oxidation of bio-molecules precursors and microbial toxins implicated in periodontal diseases and its healing and tissue regeneration properties, make the use of ozone well indicated in all stages of gingival and periodontal diseases. The primary objective of this article is to provide a general review about the clinical applications of ozone in periodontics. The secondary objective is to summarize the available in vitro and in vivo studies in Periodontics in which ozone has been used. This objective would be of importance to future researchers in terms of what has been tried and what the potentials are for the clinical application of ozone in Periodontics.

  14. Ozone therapy in periodontics

    PubMed Central

    Gupta, G; Mansi, B

    2012-01-01

    Gingival and Periodontal diseases represent a major concern both in dentistry and medicine. The majority of the contributing factors and causes in the etiology of these diseases are reduced or treated with ozone in all its application forms (gas, water, oil). The beneficial biological effects of ozone, its anti-microbial activity, oxidation of bio-molecules precursors and microbial toxins implicated in periodontal diseases and its healing and tissue regeneration properties, make the use of ozone well indicated in all stages of gingival and periodontal diseases. The primary objective of this article is to provide a general review about the clinical applications of ozone in periodontics. The secondary objective is to summarize the available in vitro and in vivo studies in Periodontics in which ozone has been used. This objective would be of importance to future researchers in terms of what has been tried and what the potentials are for the clinical application of ozone in Periodontics. PMID:22574088

  15. The High Resolution Tropospheric Ozone Residual

    NASA Technical Reports Server (NTRS)

    Schoeberl, Mark R.

    2006-01-01

    The co-flight of the MLS stratospheric limb sounder and the Ozone Monitoring Instrument (OMI) provides the capability of computing the Tropospheric Ozone Residual (TOR) in much greater detail [Ziemke et al., 2006]. Using forward trajectory calculations of MLS ozone measurements combined with OMI column ozone we have developed a high horizontal resolution tropospheric ozone residual (HTOR) which can provide even more detail than the standard TOR product. HTOR is especially useful for extra-tropical studies of tropospheric ozone transport. We find that both the Pacific pollution corridor (East Asia to Alaska) and the Atlantic pollution corridor (North America east coast to Europe) are also preferred locations for strat-trop folds leading to systematic overestimates of pollution amounts. In fact, fold events appear to dominate extra-tropical Northern Hemisphere day-to-day maps of HTOR. Model estimates of the tropospheric column are in reasonable agreement with the HTOR amounts when offsets due to different tropopause height calculations are taken into consideration.

  16. Evidence for vertical ozone redistribution since 1967

    NASA Astrophysics Data System (ADS)

    Furrer, R.; Doehler, W.; Kirsch, H.-J.; Plessing, P.; Goersdorf, U.

    1992-12-01

    Long-term measurements of ozone concentration in the vicinity of the city of Berlin have been performed with ground-based Dobson spectrophotometers and balloon borne systems. The respective experiments cover the past 24 yr. All data have been re-evaluated and corrected towards uniform calibration standards, leading to the longest lasting European data set of total column density, altitude-dependent ozone partial pressures and the corresponding temperatures. Smoothing algorithms reveal significant long-term trends. The analysis shows an increase of ozone concentration within the middle stratosphere (below 31 km height) as well as in the troposphere over the past 24 yr. On the contrary, ongoing ozone depletion in the lower stratosphere became evident. The large scale vertical redistribution of atmospheric ozone in the troposphere and the lower stratosphere seems to be in agreement with model calculations and trend predictions that have their roots in changes of the chemical composition and the ozone photochemistry due to anthropogenically induced tracer gas concentrations.

  17. The High Resolution Tropospheric Ozone Residual

    NASA Astrophysics Data System (ADS)

    Schoeberl, M. R.; Ziemke, J.; Bhartia, P.; Froidevaux, L.; Levelt, P.

    2006-12-01

    The co-flight of the MLS stratospheric limb sounder and the Ozone Monitoring Instrument (OMI) provides the capability of computing the Tropospheric Ozone Residual (TOR) in much greater detail [Ziemke et al., 2006]. Using forward trajectory calculations of MLS ozone measurements combined with OMI column ozone we have developed a high horizontal resolution tropospheric ozone residual (HTOR) which can provide even more detail than the standard TOR product. HTOR is especially useful for extra-tropical studies of tropospheric ozone transport. We find that both the Pacific pollution corridor (East Asia to Alaska) and the Atlantic pollution corridor (North America east coast to Europe) are also preferred locations for strat-trop folds leading to systematic over-estimates of pollution amounts. In fact, fold events appear to dominate extra-tropical Northern Hemisphere day-to-day maps of HTOR. Model estimates of the tropospheric column are in reasonable agreement with the HTOR amounts when offsets due to different tropopause height calculations are taken into consideration.

  18. Tropospheric Ozone Changes

    NASA Astrophysics Data System (ADS)

    Oltmans, S. J.; Lefohn, A. S.; Scheel, H.; Brunke, E. G.; Claude, H.; Tarasick, D. W.; Galbally, I.; Bodeker, G.; Redondas, A.; Simmonds, P.; Koide, T.; Schmidlin, F. J.; Harris, J. M.; Johnson, B. J.; Davies, J.; Cuevas, E.; Meyer, C.; Shadwick, D.

    2008-12-01

    Growing recognition of the role of "background" tropospheric ozone on climate forcing and as a boundary condition for air quality changes highlights the importance of obtaining a broad picture of tropospheric ozone changes. Key surface and ozonesonde observing sites with tropospheric ozone measurement records longer than ~15 years have been selected to characterize longer term tropospheric ozone changes over broad geographic regions. The sites chosen vary from those with minimal impact by local ozone pollution sources to those that are in relatively close proximity to ozone precursor emissions and are thus affected in part by these sources. Consideration is given to the extent to which various time series represent broad geographic scales. Some series with more limited geographic representativeness can provide valuable information because of the length of the record, particularly in an underrepresented region. The vertical profile information from the ozonesonde stations, which have some of the longest tropospheric ozone records, provides a unique perspective on ozone in the free troposphere that is much less influenced by more local conditions. The general slowing or flattening of ozone increases seen at a number of locations beginning in the early 1990s has generally continued. At Naha, Japan there has been a significant increase in recent years that has not been seen at other Japanese ozonesonde locations. At high latitudes over North America a decade long decline in tropospheric ozone beginning in the 1980s has generally reversed with amounts now similar to those at the beginning of the record. In the S.H. several sites in the mid latitudes have shown significant increases. Although some overall patterns on changes emerge on regional scales and in some cases on continental scales, more general conclusions on hemispheric and global scales do not emerge. This is likely consistent with the varied pattern of ozone lifetimes, precursor emission changes, and

  19. The Antarctic ozone hole

    NASA Technical Reports Server (NTRS)

    Stolarski, Richard S.

    1988-01-01

    Processes that may be responsible for the thinning in the ozone layer above the South Pole are described. The chlorine catalytic cycle which destroys ozone is described, as are the major types of reactions that are believed to interfere with this cycle by forming chlorine reservoirs. The suspected contributions of polar stratospheric clouds to these processes are examined. Finally, the possibility that the ozone hole may be due more to a shift in atmospheric dynamics than to chemical destruction is addressed.

  20. Multi sensor reanalysis of total ozone

    NASA Astrophysics Data System (ADS)

    van der A, R. J.; Allaart, M. A. F.; Eskes, H. J.

    2010-11-01

    A single coherent total ozone dataset, called the Multi Sensor Reanalysis (MSR), has been created from all available ozone column data measured by polar orbiting satellites in the near-ultraviolet Huggins band in the last thirty years. Fourteen total ozone satellite retrieval datasets from the instruments TOMS (on the satellites Nimbus-7 and Earth Probe), SBUV (Nimbus-7, NOAA-9, NOAA-11 and NOAA-16), GOME (ERS-2), SCIAMACHY (Envisat), OMI (EOS-Aura), and GOME-2 (Metop-A) have been used in the MSR. As first step a bias correction scheme is applied to all satellite observations, based on independent ground-based total ozone data from the World Ozone and Ultraviolet Data Center. The correction is a function of solar zenith angle, viewing angle, time (trend), and effective ozone temperature. As second step data assimilation was applied to create a global dataset of total ozone analyses. The data assimilation method is a sub-optimal implementation of the Kalman filter technique, and is based on a chemical transport model driven by ECMWF meteorological fields. The chemical transport model provides a detailed description of (stratospheric) transport and uses parameterisations for gas-phase and ozone hole chemistry. The MSR dataset results from a 30-year data assimilation run with the 14 corrected satellite datasets as input, and is available on a grid of 1× 1 1/2° with a sample frequency of 6 h for the complete time period (1978-2008). The Observation-minus-Analysis (OmA) statistics show that the bias of the MSR analyses is less than 1% with an RMS standard deviation of about 2% as compared to the corrected satellite observations used.

  1. Air Quality Criteria for Ozone and Related Photochemical ...

    EPA Pesticide Factsheets

    In February 2006, EPA released the final document, Air Quality Criteria for Ozone and Other Photochemical Oxidants. Tropospheric or surface-level ozone (O3) is one of six major air pollutants regulated by National Ambient Air Quality Standards (NAAQS) under the U.S. Clean Air Act. As mandated by the Clean Air Act, the U.S. Environmental Protection Agency (EPA) must periodically review the scientific bases (or criteria) for the various NAAQS by assessing newly available scientific information on a given criteria air pollutant. This document, Air Quality Criteria for Ozone and Other Photochemical Oxidants, is an updated revision of the 1996 Ozone Air Quality Criteria Document (O3 AQCD) that provided scientific bases for the current O3 NAAQS set in 1997. The Clean Air Act mandates periodic review of the National Ambient Air Quality Standards (NAAQS) for six common air pollutants, also referred to as criteria pollutants, including ozone.

  2. SMM mesospheric ozone measurements

    NASA Technical Reports Server (NTRS)

    Aikin, A. C.

    1990-01-01

    The main objective was to understand the secular and seasonal behavior of ozone in the lower mesosphere, 50 to 70 km. This altitude region is important in understanding the factors which determine ozone behavior. A secondary objective is the study of stratospheric ozone in the polar regions. Use is made of results from the SBUV satellite borne instrument. In the Arctic the interaction between chlorine compounds and low molecular weight hydrocarbons is studied. More than 30,000 profiles were obtained using the UVSP instrument on the SMM spacecraft. Several orbits of ozone data per day were obtained allowing study of the current rise in solar activity from the minimum until the present. Analysis of Nimbus 7 SBUV data in Antarctic spring indicates that ozone is depleted within the polar vortex relative to ozone outside the vortex. This depletion confirms the picture of ozone loss at altitudes where polar stratospheric clouds exist. In addition, there is ozone loss above the cloud level indicating that there is another mechanism in addition to ozone loss initiated by heterogeneous chlorine reactions on cloud particles.

  3. Ozone: Stage Two Vapor Recovery Rule and Guidance

    EPA Pesticide Factsheets

    This page includes the guidance document, fact sheet, memorandum, and final rule on removing Stage II Gasoline Vapor Control Programs from State Implementation Plans (SIP) for the Ozone National Ambient Air Quality Standards (NAAQS)

  4. Ozone trends in Atlanta, Georgia - Have emission controls been effective?

    NASA Technical Reports Server (NTRS)

    Lindsay, Ronald W.; Richardson, Jennifer L.; Chameldes, William L.

    1989-01-01

    Nine years of summertime ozone data from the Atlanta metropolitan area are analyzed and compared to local emissions of volatile organic carbon and nitrogen oxides. Trends from 1979 to 1987 were studied for the number of days per year ozone exceeded the NAAQS standard, the second-highest ozone level observed per year, and the first quartile summertime average ozone observed, as well as the mean difference between the ozone level observed downwind and upwind of the city. Because this last parameter is sensitive to chemical factors but relatively insensitive to the number of days each year with meteorological conditions conducive to ozone formation, its trend may be best suited for determining how effective emission controls have been in reducing O3 in the Atlanta area. In spite of the fact that sizeable reductions have been claimed for volatile organic carbon emissions over the past several years, the data give no indication that ozone levels have decreased and in fact, imply that summertime ozone production may have increased. The results imply that either emissions have not decreased as much as has been claimed or that ozone is not sensitive to anthropogenic volatile organic carbon emissions.

  5. Vertical ozone characteristics in urban boundary layer in Beijing.

    PubMed

    Ma, Zhiqiang; Xu, Honghui; Meng, Wei; Zhang, Xiaoling; Xu, Jing; Liu, Quan; Wang, Yuesi

    2013-07-01

    Vertical ozone and meteorological parameters were measured by tethered balloon in the boundary layer in the summer of 2009 in Beijing, China. A total of 77 tethersonde soundings were taken during the 27-day campaign. The surface ozone concentrations measured by ozonesondes and TEI 49C showed good agreement, albeit with temporal difference between the two instruments. Two case studies of nocturnal secondary ozone maxima are discussed in detail. The development of the low-level jet played a critical role leading to the observed ozone peak concentrations in nocturnal boundary layer (NBL). The maximum of surface ozone was 161.7 ppbv during the campaign, which could be attributed to abundant precursors storage near surface layer at nighttime. Vertical distribution of ozone was also measured utilizing conventional continuous analyzers on 325-m meteorological observation tower. The results showed the NBL height was between 47 and 280 m, which were consistent with the balloon data. Southerly air flow could bring ozone-rich air to Beijing, and the ozone concentrations exceeded the China's hourly ozone standard (approximately 100 ppb) above 600 m for more than 12 h.

  6. Ozone as a bioregulator. Pharmacology and toxicology of ozonetherapy today.

    PubMed

    Bocci, V

    1996-01-01

    The disinfectant activity of ozone is well recognized and ozone is used worldwide for sterilization of water. The use of ozone as a complementary medical approach is less known, because it has mostly been used in an empirical fashion without a rational basis and appropriate controls. In spite of this drawback, the use of judicious and standardized ozone dosages can elicit the formation of ROS acting as natural physiological activators of several biological functions. There is now a reasonable understanding of a few mechanisms of action and, using classical pharmacological concepts, it appears possible to formulate a rationale for optimizing clinical applications. A further exciting development is that ozone, being an oxidizer, can upregulate the intracellular anti-oxidant enzymes eventually inhibiting the constant, life-long oxidative stress responsible for degenerative diseases and aging. Among various routes for the administration of ozone, the autohemotransfusion procedure, consisting in exposing blood to ozone, i.e. to a calculated and brief oxidative stress, appears safe, simple, inexpensive and amenable to be adjusted to different pathological states It is hoped that this review will help to dispel prejudices, to clarify that ozone toxicity can be tamed, to show that ozone can act as a bioregulator and to encourage controlled clinical investigations to evaluate definitely the validity of ozonetherapy.

  7. The impact of meteorological persistence on the distribution and extremes of ozone

    NASA Astrophysics Data System (ADS)

    Sun, Wenxiu; Hess, Peter; Liu, Chengji

    2017-02-01

    CASTNET (Clean Air Status and Trends Network) ozone and temperature data and large-scale meteorological analysis are used to quantify the extent to which meteorological events and their persistence impact ozone with an emphasis on the high end of the ozone distribution (greater than the 90th percentile). Ozone increases with each successive stagnation day in all regions of the U.S., with the highest increase in the Northeastern U.S. (0.4 standard deviation or ˜4.7 ppb per successive stagnation day). Ozone increases with days since cyclone passage only in the Northeastern and Mid-Atlantic regions of the U.S., but on average not enough to reach the 90th percentile concentration. Persistent high temperature does not result in further ozone increases in any region. On the interannual timescale there is little evidence that summers with large numbers of the above events increase ozone preferentially on the high end of the ozone distribution.

  8. An evaluation of electrochemical concentration Cell (ECC) sonde measurements of atmospheric ozone

    NASA Technical Reports Server (NTRS)

    Geraci, M. J.; Luers, J. K.

    1978-01-01

    Using Dobson spectrophotometer measurements of total ozone as a comparison, an analysis of the electrochemical concentration cell (ECC) ozonesonde's measurement accuracy is presented. Days of conjunctive ECC-Dobson observations (from 1970 to 1976 at Wallops Flight Center) provide a set of 123 pairs of total ozone values. Sample set statistics are generated with means and standard deviations of total ozone values and differences being noted. An in-depth study of factors such as time assumptions used in calculating residual ozone, and other possible sources of errors are examined. A study of ECC ozone profiles is also presented with an evaluation of sonde measurement of seasonal trends, altitude or peak ozone concentration, and other important ozone parameters. Short-period changes in total ozone using Dobson data during the observational period are also described.

  9. Ozone NAAQS Review: Risk/Exposure Assessment

    EPA Science Inventory

    Ozone is one of the six major air pollutants for which EPA has issued air quality criteria and established national ambient air quality standards (NAAQS) based on those criteria. The Clear Air Act (CAA) requires EPA to periodically review and revise, as appropriate, existing air ...

  10. Sensitivity analysis of ground level ozone in India using WRF-CMAQ models

    NASA Astrophysics Data System (ADS)

    Sharma, Sumit; Chatani, Satoru; Mahtta, Richa; Goel, Anju; Kumar, Atul

    2016-04-01

    Ground level ozone is emerging as a pollutant of concern in India. Limited surface monitoring data reveals that ozone concentrations are well above the prescribed national standards. This study aims to simulate the regional and urban scale ozone concentrations in India using WRF-CMAQ models. Sector-specific emission inventories are prepared for the ozone precursor species at a finer resolution (36 × 36 km2) than used in previous studies. Meteorological fields developed using the WRF model are fed into the CMAQ model along with the precursor emissions to simulate ozone concentrations at a regional scale. The model is validated using observed ozone dataset. Sensitivity analysis is carried out to understand the effect of different precursor species and sources on prevailing ozone concentrations in India. The results show that NOx sensitive conditions prevail in India and control of NOx will result in more reduction in ozone than VOCs. However, further growth in the transport and power sector and decreasing VOC emissions from the residential sector may increase the sensitivity of VOCs towards ozone in the future. At the urban scale, presence of high NOx emissions form VOC limited conditions and reduction of NOx results in increase in ozone concentrations. However, this will help in improving regional scale ozone pollution in the downwind regions. A non-linear response has been observed while assessing the sectoral sensitivities of ozone formation. Transport sector is found to have the maximum potential for reducing ozone concentrations in India.

  11. Ozone and temperature trends

    NASA Technical Reports Server (NTRS)

    Stolarski, Richard S.; Fioletov, Vitali; Bishop, Lane; Godin, Sophie; Bojkov, Rumen D.; Kirchhoff, Volker; Chanin, Marie-Lise; Zawodny, Joseph M.; Zerefos, Christos S.; Chu, William

    1991-01-01

    An update of the extensive reviews of the state of knowledge of measured ozone trends published in the Report of the International Ozone Trends Panel is presented. The update contains a review of progress since these reports, including reviewing of the ozone records, in most cases through March 1991. Also included are some new, unpublished reanalyses of these records including a complete reevaluation of 29 stations located in the former Soviet Union. The major new advance in knowledge of the measured ozone trend is the existence of independently calibrated satellite data records from the Total Ozone Mapping Spectrometer (TOMS) and Stratospheric Aerosol and Gas Experiment (SAG) instruments. These confirm many of the findings, originally derived from the Dobson record, concerning northern mid-latitude changes in ozone. We now have results from several instruments, whereas the previously reported changes were dependent on the calibration of a single instrument. This update will compare the ozone records from many different instruments to determine whether or not they provide a consistent picture of the ozone change that has occurred in the atmosphere. The update also briefly considers the problem of stratospheric temperature change. As in previous reports, this problem received significantly less attention, and the report is not nearly as complete. This area needs more attention in the future.

  12. Saving Our Ozone Shield.

    ERIC Educational Resources Information Center

    Lacoste, Beatrice

    1992-01-01

    Discusses the introduction and continued use of chlorofluorocarbons (CFCs) as related to stratospheric ozone depletion. Presents the characteristics of CFCs conducive to the chemical reaction with ozone, the history of CFC use and detection of related environmental problems, health hazards, and alternatives to CFC use. (MCO)

  13. Polar Ozone Workshop. Abstracts

    NASA Technical Reports Server (NTRS)

    Aikin, Arthur C.

    1988-01-01

    Results of the proceedings of the Polar Ozone Workshop held in Snowmass, CO, on May 9 to 13, 1988 are given. Topics covered include ozone depletion, ozonometry, polar meteorology, polar stratospheric clouds, remote sensing of trace gases, atmospheric chemistry and dynamical simulations.

  14. The Antarctic Ozone Hole.

    ERIC Educational Resources Information Center

    Stolarski, Richard S.

    1988-01-01

    Discusses the Airborne Antarctic Ozone Experiment (1987) and the findings of the British Antarctic Survey (1985). Proposes two theories for the appearance of the hole in the ozone layer over Antarctica which appears each spring; air pollution and natural atmospheric shifts. Illustrates the mechanics of both. Supports worldwide chlorofluorocarbon…

  15. Observing trends in total ozone and extreme ozone events

    NASA Astrophysics Data System (ADS)

    Balcerak, Ernie

    2014-05-01

    The ozone layer in the stratosphere has been recovering since the 1989 Montreal Protocol reduced the use of ozone-destroying chlorofluorocarbons. Fitzka et al. observed trends in total ozone levels and the vertical distribution of ozone at Hoher Sonnblick, a mountain in Austria, from 1994 to 2011.

  16. The Hole in the Ozone Layer.

    ERIC Educational Resources Information Center

    Hamers, Jeanne S.; Jacob, Anthony T.

    This document contains information on the hole in the ozone layer. Topics discussed include properties of ozone, ozone in the atmosphere, chlorofluorocarbons, stratospheric ozone depletion, effects of ozone depletion on life, regulation of substances that deplete the ozone layer, alternatives to CFCs and Halons, and the future of the ozone layer.…

  17. Air sampling of aromatic hydrocarbons in the presence of ozone by solid-phase microextraction.

    PubMed

    Xiong, Gouhua; Koziel, Jacek A; Pawliszyn, Janusz

    2004-01-30

    Effects of ozone on air sampling of standard gas mixtures of aromatic hydrocarbons were tested using solid-phase microextraction (SPME). Standard concentrations of ozone ranging from 10 ppb (v/v) to 6400 ppm (v/v) were generated using an in-house built ozone generator based on corona discharge. Effects of temperature, discharge voltage, and oxygen flow on the ozone generation were tested. The working dc voltage had the greatest effect on generated ozone concentration and was proportional to the ozone concentration. Generation temperature and oxygen flow rate were inversely proportional to ozone concentrations. Produced ozone was mixed with standard benzene, toluene, ethylbenzene, and xylenes (BTEX) gas at less than 100 ppb (v/v). Air samples were collected with poly(dimethylsiloxane) (PDMS) 100 microm SPME fibers and analyzed by gas chromatography (GC)-flame ionization detection (FID) and GC-MS. Significant reductions of BTEX concentrations were observed. In addition, some products of BTEX-ozone-oxygen reactions were identified. SPME worked well as a rapid sampler for BTEX and BTEX-ozone-oxygen reaction products. No significant deterioration of the PDMS coating and no significant reduction of absorption capacity were observed after repeated exposure to ozone.

  18. The ASSET intercomparison of ozone analyses: method and first results

    NASA Astrophysics Data System (ADS)

    Geer, A. J.; Lahoz, W. A.; Bekki, S.; Bormann, N.; Errera, Q.; Eskes, H. J.; Fonteyn, D.; Jackson, D. R.; Juckes, M. N.; Massart, S.; Peuch, V.-H.; Rharmili, S.; Segers, A.

    2006-12-01

    This paper aims to summarise the current performance of ozone data assimilation (DA) systems, to show where they can be improved, and to quantify their errors. It examines 11 sets of ozone analyses from 7 different DA systems. Two are numerical weather prediction (NWP) systems based on general circulation models (GCMs); the other five use chemistry transport models (CTMs). The systems examined contain either linearised or detailed ozone chemistry, or no chemistry at all. In most analyses, MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) ozone data are assimilated; two assimilate SCIAMACHY (Scanning Imaging Absorption Spectrometer for Atmospheric Chartography) observations instead. Analyses are compared to independent ozone observations covering the troposphere, stratosphere and lower mesosphere during the period July to November 2003. Biases and standard deviations are largest, and show the largest divergence between systems, in the troposphere, in the upper-troposphere/lower-stratosphere, in the upper-stratosphere and mesosphere, and the Antarctic ozone hole region. However, in any particular area, apart from the troposphere, at least one system can be found that agrees well with independent data. In general, none of the differences can be linked to the assimilation technique (Kalman filter, three or four dimensional variational methods, direct inversion) or the system (CTM or NWP system). Where results diverge, a main explanation is the way ozone is modelled. It is important to correctly model transport at the tropical tropopause, to avoid positive biases and excessive structure in the ozone field. In the southern hemisphere ozone hole, only the analyses which correctly model heterogeneous ozone depletion are able to reproduce the near-complete ozone destruction over the pole. In the upper-stratosphere and mesosphere (above 5 hPa), some ozone photochemistry schemes caused large but easily remedied biases. The diurnal cycle of ozone in the

  19. The Two Faces of Ozone.

    ERIC Educational Resources Information Center

    Monastersky, Richard

    1989-01-01

    Provides answers to questions regarding the ozone problem: (1) nature of ozone in the troposphere and stratosphere; (2) possibility of sending the excess ozone at ground level to the stratosphere; (3) possibility of producing pure ozone and carrying it to the stratosphere; and (4) banning chlorofluorocarbons. (YP)

  20. Fundamentals of ISCO Using Ozone

    EPA Science Inventory

    In situ chemical oxidation (ISCO) using ozone involves the introduction of ozone gas (O3) into the subsurface to degrade organic contaminants of concern. Ozone is tri-molecular oxygen (O2) that is a gas under atmospheric conditions and is a strong oxidant. Ozone may react with ...

  1. A video atlas of TOMS ozone data, 1978-88

    NASA Technical Reports Server (NTRS)

    Chesters, D.; Krueger, A. J.

    1989-01-01

    The Total Ozone Mapping Spectrometer (TOMS), on-board NASA's Nimbus-7 weather satellite, has been observing ozone over the earth once daily for the last 10 yr. A time-lapse atlas of 3440 color-coded images drawn from the TOMS archive from 1978 to 1988 has been visualized on a standard VHS videotape that is now available from NASA. The rapid and complex ozone variations presented demonstrate the difficulty of separating man-induced climate changes from natural variability. This article presents a few images from the atlas and describes interesting features in the animation, such as the correlation between ozone and 'the weather', and the recent deepening of the annual ozone hole over the South Pole. Originally intended as a browsing tool for the TOMS digital database, the videotape is a vivid presentation of the earth's atmospheric dynamics and chemistry that is recommended for scientists, educators, policy makers, and citizens concerned about the global environment.

  2. Minireview: the health implications of water treatment with ozone

    SciTech Connect

    Carmichael, N.G.; Winder, C.; Borges, S.H.; Backhouse, B.L.; Lewis, P.D.

    1982-01-11

    Ozone is a highly efficient disinfectant which may have significant advantages in water treatment compared to chlorine. It has, however, been shown that mutagenic and possibly carcinogenic byproducts may be produced under certain conditions of ozonation. Light chlorination following ozonization may meet the highest standards of disinfection. In addition the destruction of much of the organic matter by prior ozone treatment may well result in less harmful chlorinated and brominated products in the finished water. In many cases ozone treatment alone may suffice. It would be desirable to test with long term in vivo experiments which of the alternatives produces the best combination of microbiologically clean and pleasant water with minimum mutagenic and carcinogenic effect.

  3. Ozone - plant surface reactions an important ozone loss term?

    NASA Astrophysics Data System (ADS)

    Hansel, Armin; Jud, Werner; Fischer, Lukas; Canaval, Eva; Wohlfahrt, Georg; Tissier, Alain

    2015-04-01

    Elevated tropospheric ozone concentrations are considered a toxic threat to plants responsible for global crop losses with associated economic costs of several billions dollar per year. Plant injuries have been related to the uptake of ozone through stomatal pores and oxidative effects damaging the internal leaf tissue. But a striking question remains: How much ozone enters the plant through open stomata and how much ozone is lost by chemical reactions at the plant surface? Until now surface losses are estimated from measured total ozone deposition fluxes and calculated stomatal conductance values. While stomatal conductance of CO2 and H2O is well understood and extensively used in describing plant atmosphere gas exchange, stomatal conductance of ozone is not well known. Here we use different Nicotiana tabacum varieties and find that surface reactions of ozone with diterpenoids synthesized by glandular trichomes reduce ozone flux through open stomata. Our measurements reveal that fast ozone loss at the plant surface is accompanied with prompt release of oxygenated volatile compounds. In the ozone fumigation experiments of different Nicotiana tabacum varieties the release of specific volatile oxy-VOCs allowed to identify the semi volatile precursor compounds at the plant surface. Ozone fumigation experiments with Norway spruce (Picea abies) and Scots Pine (Pinus sylvestris), two common species in the Northern Hemisphere, show also a significant ozone loss at the plant surface for Picea abies. Fluid dynamic calculations of ozone transport in the diffusive leaf boundary layer reveal a vertical but no horizontal ozone gradient thus reducing ozone fluxes through the pores in case of efficient ozone scavenging plant surfaces. We explain this efficient ozone protection mechanism by the porous surface architecture of plants in combination with unsaturated semi-volatile compounds deposited at the plant surface. These results show that unsaturated semi-volatile compounds at

  4. Record low global ozone in 1992

    SciTech Connect

    Gleason, J.F. ); Bhartia, P.K.; Herman, J.R.; McPeters, R.; Newman, P.; Stolarski, R.S. ); Flynn, L. ); Labow, G.; Larko, D.; Seftor, C.; Wellemeyer, C. ); Komhyr, W.D. ); Miller, A.J.; Planet, W. )

    1993-04-23

    The 1992 global average total ozone, measured by the Total Ozone Mapping Spectrometer (TOMS) on the Nimbus-7 satellite, was 2 to 3 percent lower than any earlier year observed by TOMS (1979 to 1991). Ozone amounts were low in a wide range of latitudes in both the Northern and Southern hemispheres, and the largest decreases were in the regions from 10[degrees]S to 20[degrees]S and 10[degrees]N to 60[degrees]N. Global ozone in 1992 is at least 1.5 percent lower than would be predicted by a statistical model that includes a linear trend and accounts for solar cycle variation and the quasi-biennial oscillation. These results are confirmed by comparisons with data from other ozone monitoring instruments: the SBUV/2 instrument on the NOAA-11 satellite, the TOMS instrument on the Russian Meteor-3 satellite, the World Standard Dobson instrument 83, and a collection of 22 ground-based Dobson instruments.

  5. Stratospheric ozone depletion

    PubMed Central

    Rowland, F. Sherwood

    2006-01-01

    Solar ultraviolet radiation creates an ozone layer in the atmosphere which in turn completely absorbs the most energetic fraction of this radiation. This process both warms the air, creating the stratosphere between 15 and 50 km altitude, and protects the biological activities at the Earth's surface from this damaging radiation. In the last half-century, the chemical mechanisms operating within the ozone layer have been shown to include very efficient catalytic chain reactions involving the chemical species HO, HO2, NO, NO2, Cl and ClO. The NOX and ClOX chains involve the emission at Earth's surface of stable molecules in very low concentration (N2O, CCl2F2, CCl3F, etc.) which wander in the atmosphere for as long as a century before absorbing ultraviolet radiation and decomposing to create NO and Cl in the middle of the stratospheric ozone layer. The growing emissions of synthetic chlorofluorocarbon molecules cause a significant diminution in the ozone content of the stratosphere, with the result that more solar ultraviolet-B radiation (290–320 nm wavelength) reaches the surface. This ozone loss occurs in the temperate zone latitudes in all seasons, and especially drastically since the early 1980s in the south polar springtime—the ‘Antarctic ozone hole’. The chemical reactions causing this ozone depletion are primarily based on atomic Cl and ClO, the product of its reaction with ozone. The further manufacture of chlorofluorocarbons has been banned by the 1992 revisions of the 1987 Montreal Protocol of the United Nations. Atmospheric measurements have confirmed that the Protocol has been very successful in reducing further emissions of these molecules. Recovery of the stratosphere to the ozone conditions of the 1950s will occur slowly over the rest of the twenty-first century because of the long lifetime of the precursor molecules. PMID:16627294

  6. Stratospheric ozone depletion.

    PubMed

    Rowland, F Sherwood

    2006-05-29

    Solar ultraviolet radiation creates an ozone layer in the atmosphere which in turn completely absorbs the most energetic fraction of this radiation. This process both warms the air, creating the stratosphere between 15 and 50 km altitude, and protects the biological activities at the Earth's surface from this damaging radiation. In the last half-century, the chemical mechanisms operating within the ozone layer have been shown to include very efficient catalytic chain reactions involving the chemical species HO, HO2, NO, NO2, Cl and ClO. The NOX and ClOX chains involve the emission at Earth's surface of stable molecules in very low concentration (N2O, CCl2F2, CCl3F, etc.) which wander in the atmosphere for as long as a century before absorbing ultraviolet radiation and decomposing to create NO and Cl in the middle of the stratospheric ozone layer. The growing emissions of synthetic chlorofluorocarbon molecules cause a significant diminution in the ozone content of the stratosphere, with the result that more solar ultraviolet-B radiation (290-320 nm wavelength) reaches the surface. This ozone loss occurs in the temperate zone latitudes in all seasons, and especially drastically since the early 1980s in the south polar springtime-the 'Antarctic ozone hole'. The chemical reactions causing this ozone depletion are primarily based on atomic Cl and ClO, the product of its reaction with ozone. The further manufacture of chlorofluorocarbons has been banned by the 1992 revisions of the 1987 Montreal Protocol of the United Nations. Atmospheric measurements have confirmed that the Protocol has been very successful in reducing further emissions of these molecules. Recovery of the stratosphere to the ozone conditions of the 1950s will occur slowly over the rest of the twenty-first century because of the long lifetime of the precursor molecules.

  7. Decadal evolution of atmospheric ozone and remote sensing of tropospheric ozone

    NASA Astrophysics Data System (ADS)

    Jiang, Yibo

    1997-09-01

    In chapter 1, the decadal evolution of the Antarctic ozone hole is studied by using ozone column amounts obtained by the total ozone mapping spectrometer (TOMS) in the southern polar region during late austral winter and spring (Days 240-300) for 1980-1991 using area- mapping techniques and area-weighted vortex averages. The vortex here is defined using the -50 PVU contour on the 500 K isentropic surface. There is a distinct change after 1985 in the vortex averaged column ozone depletion rate during September and October, the period of maximum ozone loss. The mean ozone depletion rate in the vortex between Day 240 and the day of minimum vortex-averaged ozone is about 1 DU/day at the beginning of the decade, increasing to about 1.8 DU/day by 1985, and then apparently saturating thereafter. The vortex-average column ozone during September and October has declined at the rate of 11.3 DU/yr (3.8%) from 1980 to 1987 and at a smaller rate of 2 DU/yr (0.9%) from 1987 to 1991. In chapter 2, we show that standard deviation of column ozone from the zonal mean (COSDZ) provides a measure of the longitudinal inhomogeneity in column ozone and dynamical wave activities in the atmosphere. Simulation of this quantity by three-dimensional (3-D) models could provide a sensitive check on the wave activities in the stratosphere that are responsible for ozone transport. Analysis of the TOMS data shows a profound secular change in COSDZ from 1979 to 1992. In the southern higher latitudes, COSDZ shows a significant increase around 65o in August and September, whereas the changes are much smaller in the northern higher latitudes in the boreal spring. In chapter 3, an estimate of tropospheric ozone levels over tropical pacific South America is obtained from the difference in the TOMS data between the high Andes and the Pacific Ocean. From 1979 to 1992 tropospheric ozone apparently increased by 1.47 ± 0.40 %/yr or 0.21 ± 0.06 DU/yr over South America and the surrounding oceans. We model

  8. A Holistic Evaluation of the Houston, Texas Ozone Attainment Episode

    NASA Astrophysics Data System (ADS)

    Biton, L.; Vizuete, W.; Kim, B.; Jeffries, H. E.

    2006-12-01

    In early 2006, the Texas Commission on Environmental Quality (TCEQ) released a simulation episode to form the basis for its 8-Hour Ozone State Implementation Plan (SIP). The SIP details steps to be taken to bring the Houston-Galveston-Brazoria region into attainment of the National Ambient Air Quality Standard for ozone (O3). The modeling episode will have significant impacts on regulatory decision-making, thus affecting the regional economy and human health. At present model performance evaluations (MPEs) are based on guidelines set by the Environmental Protection Agency (EPA) that rely heavily on statistical measures. While the episode falls within the recommended range for these EPA statistical metrics, examining the level of agreement between model predictions and observations for O3 is not a sufficient method to assess model accuracy. We have discovered severe inaccuracies in the 8-Hour modeling episode with an evaluation methodology that recognizes that (1) the formation of tropospheric O3 system is non-linear with respect to its precursors and (2) is the result of a multitude of chemical, emission, and meteorological processes. This paper presents the results of this improved evaluation method using new tools and software developed at the University of North Carolina at Chapel Hill. These tools were designed specifically to compensate for inadequacies in the existing statistical methods currently used for MPE. These tools enable investigators to review O3 production and concentrations in the context of meteorological and chemical conditions, allowing more holistic analytical techniques, not captured by traditional statistical metrics. In our analysis all modeling results are compared with high-resolution data from multiple sources, including an extensive ground-monitoring network, automatic gas-chromatographs (auto-GCs), and aircraft. First in our investigation, as a measure of progress, the latest 8-Hour episode is compared to TCEQ"s previous 1-Hour O3 SIP

  9. Photoenhanced degradation of veratraldehyde upon the heterogeneous ozone reactions.

    PubMed

    Net, Sopheak; Gligorovski, Sasho; Pietri, Sylvia; Wortham, Henri

    2010-07-21

    Light-induced heterogeneous reactions between gas-phase ozone and veratraldehyde adsorbed on silica particles were performed. At an ozone mixing ratio of 250 ppb, the loss of veratraldehyde largely increased from 1.81 x 10(-6) s(-1) in the dark to 2.54 x 10(-5) s(-1) upon exposure to simulated sunlight (lambda > 300 nm). The observed rates of degradation exhibited linear dependence with the ozone in the dark ozonolysis experiments which change in the non-linear Langmuir-Hinshelwood dependence in the experiments with simultaneous ozone and light exposure of the coated particles. When the coated silica particles were exposed only to simulated sunlight in absence of ozone the loss of veratraldehyde was about three times higher i.e. 5.97 x 10(-6) s(-1) in comparison to the ozonolysis experiment under dark conditions at 250 ppb ozone mixing ratio, 1.81 x 10(-6) s(-1).These results clearly show that the most important loss of veratraldehyde occurs under simultaneous ozone and light exposure of the coated silica particles. The main identified product in the heterogeneous reactions between gaseous ozone and adsorbed veratraldehyde under dark conditions and in presence of light was veratric acid.Carbon yields of veratric acid were calculated and the obtained results indicated that at low ozone mixing ratio (250 ppb) the carbon yield obtained under dark conditions is 70% whereas the carbon yield obtained in the experiments with simultaneous ozone and light exposure of the coated particles is 40%. In both cases the carbon yield of veratric acid exponentially decayed leading to the plateau ( approximately 35% of carbon yield) at an ozone mixing ratio of 6 ppm. Two reaction products i.e. 3-hydroxy-4-methoxybenzoic acid and 4-hydroxy-3-methoxybenzoic acid were identified (confirmed with the standards) only in the experiments performed under simultaneous ozonolysis and light irradiation of the particles.

  10. Ozone Profiles and Tropospheric Ozone from Global Ozone Monitoring Experiment

    NASA Technical Reports Server (NTRS)

    Liu, X.; Chance, K.; Sioris, C. E.; Sparr, R. J. D.; Kuregm, T. P.; Martin, R. V.; Newchurch, M. J.; Bhartia, P. K.

    2003-01-01

    Ozone profiles are derived from backscattered radiances in the ultraviolet spectra (290-340 nm) measured by the nadir-viewing Global Ozone Monitoring Experiment using optimal estimation. Tropospheric O3 is directly retrieved with the tropopause as one of the retrieval levels. To optimize the retrieval and improve the fitting precision needed for tropospheric O3, we perform extensive wavelength and radiometric calibrations and improve forward model inputs. Retrieved O3 profiles and tropospheric O3 agree well with coincident ozonesonde measurements, and the integrated total O3 agrees very well with Earth Probe TOMS and Dobson/Brewer total O3. The global distribution of tropospheric O3 clearly shows the influences of biomass burning, convection, and air pollution, and is generally consistent with our current understanding.

  11. Multi-model Comparison of Lateral Boundary Contributions to Ozone Concentrations over the United States (CMAS Presentation)

    EPA Science Inventory

    As the National Ambient Air Quality Standards (NAAQS) for ozone become more stringent, there has been growing attention on characterizing the contributions and the uncertainties in ozone from outside the US to the ozone concentrations within the US. The third phase of the Air Qua...

  12. 40 CFR 51.914 - What new source review requirements apply for 8-hour ozone nonattainment areas?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... apply for 8-hour ozone nonattainment areas? 51.914 Section 51.914 Protection of Environment... OF IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient Air Quality Standard § 51.914 What new source review requirements apply for 8-hour ozone nonattainment areas?...

  13. 40 CFR 51.916 - What are the requirements for an Ozone Transport Region under the 8-hour NAAQS?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 2 2013-07-01 2013-07-01 false What are the requirements for an Ozone... IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient Air Quality Standard § 51.916 What are the requirements for an Ozone Transport Region under the 8-hour NAAQS? (a) In...

  14. 40 CFR 51.916 - What are the requirements for an Ozone Transport Region under the 8-hour NAAQS?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 2 2014-07-01 2014-07-01 false What are the requirements for an Ozone... IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient Air Quality Standard § 51.916 What are the requirements for an Ozone Transport Region under the 8-hour NAAQS? (a) In...

  15. 40 CFR 51.914 - What new source review requirements apply for 8-hour ozone nonattainment areas?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... apply for 8-hour ozone nonattainment areas? 51.914 Section 51.914 Protection of Environment... OF IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient Air Quality Standard § 51.914 What new source review requirements apply for 8-hour ozone nonattainment areas?...

  16. 40 CFR 51.914 - What new source review requirements apply for 8-hour ozone nonattainment areas?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... apply for 8-hour ozone nonattainment areas? 51.914 Section 51.914 Protection of Environment... OF IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient Air Quality Standard § 51.914 What new source review requirements apply for 8-hour ozone nonattainment areas?...

  17. 40 CFR 51.916 - What are the requirements for an Ozone Transport Region under the 8-hour NAAQS?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 2 2011-07-01 2011-07-01 false What are the requirements for an Ozone... IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient Air Quality Standard § 51.916 What are the requirements for an Ozone Transport Region under the 8-hour NAAQS? (a) In...

  18. 40 CFR 51.916 - What are the requirements for an Ozone Transport Region under the 8-hour NAAQS?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 2 2012-07-01 2012-07-01 false What are the requirements for an Ozone... IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient Air Quality Standard § 51.916 What are the requirements for an Ozone Transport Region under the 8-hour NAAQS? (a) In...

  19. 40 CFR 51.914 - What new source review requirements apply for 8-hour ozone nonattainment areas?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... apply for 8-hour ozone nonattainment areas? 51.914 Section 51.914 Protection of Environment... OF IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient Air Quality Standard § 51.914 What new source review requirements apply for 8-hour ozone nonattainment areas?...

  20. 40 CFR 51.916 - What are the requirements for an Ozone Transport Region under the 8-hour NAAQS?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 2 2010-07-01 2010-07-01 false What are the requirements for an Ozone... IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient Air Quality Standard § 51.916 What are the requirements for an Ozone Transport Region under the 8-hour NAAQS? (a) In...

  1. 40 CFR 51.914 - What new source review requirements apply for 8-hour ozone nonattainment areas?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... apply for 8-hour ozone nonattainment areas? 51.914 Section 51.914 Protection of Environment... OF IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient Air Quality Standard § 51.914 What new source review requirements apply for 8-hour ozone nonattainment areas?...

  2. The impact of meteorology on ozone in Houston

    SciTech Connect

    Eder, B.K.; Davis, J.M.; Nychka, D.

    1997-12-31

    This paper compares the results from both a one-stage hierarchical clustering technique (average linkage) and a two-stage technique (average linkage then k-means) as part of an objective meteorological Classification scheme designed to better elucidate ozone`s dependence on meteorology in the Houston, Texas, area. When applied to twelve years of meteorological data (1981-1992), each technique identified seven statistically distinct meteorological regimes, the majority of which exhibited significantly different daily 1-hour maximum ozone (O{sub 3}) concentrations. While both clustering approaches proved successful, the two-stage approach did appear superior in terms of better segregation of the mean O{sub 3}, concentrations. Both approaches indicated that the largest mean daily one-hour maximum concentrations are associated with migrating anticyclones and not with the quasi-permanent Bermuda High that often dominates the southeastern United States during the summer. As a result, maximum ozone concentrations are just as likely during the months of April, May, September and October as they are during the summer months. These findings support and help explain the unique O{sub 3}, climatology experienced by the Houston area.

  3. Polar Ozone Losses

    NASA Technical Reports Server (NTRS)

    Newman, Paul A.; Bhartia, P. K. (Technical Monitor)

    2001-01-01

    Since the discovery of the Antarctic ozone hole, a great deal of attention has been focused on the polar regions to both identify the chemistry and physics of the large losses, and to provide an understanding of the future of polar ozone. In this review talk, I will discuss the secular trends of ozone in both the Antarctic and Arctic regions, and I will review some of the principal research results of the last few years. In particular, I will emphasize some of the results from the SOLVE-THESEO 2000 campaign that occurred over the course of the winter of 1999-2000.

  4. Tropical tropospheric ozone: Processes highlighted by covariations of ozone and its sources

    NASA Astrophysics Data System (ADS)

    Chatfield, R.; Guan, H.; Thompson, A.; Hudson, R.; Witte, J.

    2003-04-01

    Wavelet and spectral analyses techniques provide promising early results which empirically highlight those processes which determine upper tropospheric ozone. Tropical and subtropical tropospheric ozone are important radiatively active species, with particularly large effects in the upper third of the troposphere. Atmospheric chemistry investigations using 3-D models and local analyses have corroborated roles for large scale dynamics, vertical mixing and redistribution through convection, and advection of pollution ozone or its precursors. Temporal variability of O_3 has proved difficult to simulate. Thus, individual roles of lightning, biomass burning, and other pollution in providing precursor NO_x, radicals, and chain carriers (CO, hydrocarbons) remain unquantified by simulation, and it is theoretically reasonable that individual roles are magnified by a joint synergy. We report on empirical studies linking time variations apparent in several datasets: a TTO (Tropical Tropospheric Ozone) product derived from TOMS (the Total Ozone Mapping Spectrometer), the SHADOZ (Southern Hemisphere Additional Ozonesondes) network stations (Nairobi, Fiji), and auxiliary series with power to explain ozone-deterimining processes. These auxliary series are The OTD/LIS (Optical Transient Detector/Lightning Imaging Sensor) measurements of the lightning NO_x source, the OLR (Outgoing Longwave Radiation) measurement of high-topped clouds, and standard meteorological variables from the United States NCEP and Data Assimilation Office analyses. Concentrating on equatorial ozone, we compare the statistical evidence on the variability of tropospheric ozone. Important variations occur on approximately two-week, two-month (Madden-Julian Oscillation) and annual scales. We report initial results defining relative roles of the processed mentioned affecting O_3 using their covariance properties.

  5. Response of Federal Land Management Agencies to ozone impacts on vegetation

    SciTech Connect

    Musselman, R.C.; Fisher, R.W.

    1999-07-01

    The FLAG (Federal Land Manager's AQRV WorkGroup) Ozone Subgroup was organized to compile information known about response of vegetation to ozone in federally managed parks, forests, and wildlife refuges; to document areas of agreement among federal agencies regarding identification of ozone sensitive Air Quality Related Values (AQRVs); and standardize agency responses to New Source Review (NSR) permit applications. Subgroup members included air resource managers and ozone effects scientists from several agencies that manage federal lands. The subgroup identified sensitive AQRV receptors, determined information needed to evaluate permit applications under the NSR process, determined the form of an ozone parameter to use to relate plant response to ambient ozone, and agreed on specific definitions for vegetation injury and damage from ozone. The subgroup developed specific protocols for federal agencies to follow in response to NSR permit applications. These protocols were based on (1) ambient levels of ozone as measured by the W126 ozone metric and the number of peak ozone concentrations $100 ppb (N100), and (2) the presence or absence of ozone sensitive plant species and ozone-induced damage to vegetation.

  6. Forecasting of daily total atmospheric ozone in Isfahan.

    PubMed

    Yazdanpanah, H; Karimi, M; Hejazizadeh, Z

    2009-10-01

    A neural network combined to an artificial neural network model is used to forecast daily total atmospheric ozone over Isfahan city in Iran. In this work, in order to forecast the total column ozone over Isfahan, we have examined several neural networks algorithms with different meteorological predictors based on the ozone-meteorological relationships with previous day's ozone value. The meteorological predictors consist of temperatures (dry and dew point) and geopotential heights at standard levels of 100, 50, 30, 20 and 10 hPa with their wind speed and direction. These data together with previous day total ozone forms the input matrix of the neural model that is based on the back propagation algorithm (BPA) structure. The output matrix is the daily total atmospheric ozone. The model was build based on daily data from 1997 to 2004 obtained from Isfahan ozonometric station data. After modeling these data we used 3 year (from 2001 to 2003) of daily total ozone for testing the accuracy of model. In this experiment, with the final neural network, the total ozone are fairly well predicted, with an Agreement Index 76%.

  7. Increasing Springtime Ozone Mixing Ratios in the Free Troposphere Over Western North America

    NASA Technical Reports Server (NTRS)

    Cooper, O. R.; Parrish, D. D.; Stohl, A.; Trainer, M.; Nedelec, P.; Thouret, V.; Cammas, J. P.; Oltmans, S. J.; Johnson, B. J.; Tarasick, D.; Leblanc, T.; McDermid, I. S.; Jaffe, D.; Gao, R.; Stith, J.; Ryerson, T.; Aikin, K.; Campos, T.; Weinheimer, A.; Avery, M. A.

    2010-01-01

    In the lowermost layer of the atmosphere - the troposphere - ozone is an important source of the hydroxyl radical, an oxidant that breaks down most pollutants and some greenhouse gases. High concentrations of tropospheric ozone are toxic, however, and have a detrimental effect on human health and ecosystem productivity1. Moreover, tropospheric ozone itself acts as an effective greenhouse gas. Much of the present tropospheric ozone burden is a consequence of anthropogenic emissions of ozone precursors resulting in widespread increases in ozone concentrations since the late 1800s. At present, east Asia has the fastest-growing ozone precursor emissions. Much of the springtime east Asian pollution is exported eastwards towards western North America. Despite evidence that the exported Asian pollution produces ozone, no previous study has found a significant increase in free tropospheric ozone concentrations above the western USA since measurements began in the late 1970s. Here we compile springtime ozone measurements from many different platforms across western North America. We show a strong increase in springtime ozone mixing ratios during 1995-2008 and we have some additional evidence that a similar rate of increase in ozone mixing ratio has occurred since 1984. We find that the rate of increase in ozone mixing ratio is greatest when measurements are more heavily influenced by direct transport from Asia. Our result agrees with previous modelling studies, which indicate that global ozone concentrations should be increasing during the early part of the twenty-first century as a result of increasing precursor emissions, especially at northern mid-latitudes, with western North America being particularly sensitive to rising Asian emissions. We suggest that the observed increase in springtime background ozone mixing ratio may hinder the USA s compliance with its ozone air quality standard.

  8. Altitude troposphere ozone profiles over Kyiv-Goloseyev station by simultaneous Umkehr and FTIR observations

    NASA Astrophysics Data System (ADS)

    Milinevsky, Gennadi; Shavrina, Angelina; Udodov, Evgeny; Liptuga, Anatoly; Kyslyi, Volodymyr; Danylevsky, Vassyl; Kravchenko, Volodymyr; Ivanov, Yuri; Synyavski, Ivan; Romanyuk, Yaroslav; Pavlenko, Yakov; Veles, Oleksandr

    2016-04-01

    Total ozone column and ozone profile data have been obtained from both: (1) standard Dobson measurements and Umkehr method, and (2) using modeling of the ozone absorption spectral band profile near 9.6 microns with the MODTRAN4.3 Atmospheric Radiation Transfer Model based on the HITRAN molecular absorption database from Fourier transform infrared spectroscopy (FTIR) observations. The simultaneous ground-based Dobson/Umkehr and FTIR ozone observations have been performed in 2014-2015 at the mid-latitude Kyiv-Goloseyev KGV GAW station for joint altitude troposphere ozone profiles analysis. To retrieve ozone column estimates and ozone profiles from FTIR observations, we used the satellite Aqua-AIRS water vapor, temperature and ozone profiles, and the simultaneous with FTIR observations the Umkehr ozone profiles and surface ozone measurements as input a priori information for the MODTRAN4.3 model. The altitude ozone profiles retrieved from Umkehr method and satellite measurements are in good correspondence in stratosphere layer. However the troposphere part of ozone profiles is uncertain and reproduced with large errors. Therefore we use the MODTRAN4.3 model for interpretation of observed FTIR absorption spectrum to retrieve and improve the troposphere part of ozone altitude distribution. The synergy of Umkehr, satellite and FTIR simultaneous observations including surface ozone measurements allows rendering the ozone profile features in troposphere that indicate the stratosphere-troposphere exchange processes. Season ozone profile variations observed from Umkehr measurements are discussed as well. This work was partly supported by the Polar FORCeS project no. 4012 of the Australian Antarctic Science Program.

  9. Increasing springtime ozone mixing ratios in the free troposphere over western North America.

    PubMed

    Cooper, O R; Parrish, D D; Stohl, A; Trainer, M; Nédélec, P; Thouret, V; Cammas, J P; Oltmans, S J; Johnson, B J; Tarasick, D; Leblanc, T; McDermid, I S; Jaffe, D; Gao, R; Stith, J; Ryerson, T; Aikin, K; Campos, T; Weinheimer, A; Avery, M A

    2010-01-21

    In the lowermost layer of the atmosphere-the troposphere-ozone is an important source of the hydroxyl radical, an oxidant that breaks down most pollutants and some greenhouse gases. High concentrations of tropospheric ozone are toxic, however, and have a detrimental effect on human health and ecosystem productivity. Moreover, tropospheric ozone itself acts as an effective greenhouse gas. Much of the present tropospheric ozone burden is a consequence of anthropogenic emissions of ozone precursors resulting in widespread increases in ozone concentrations since the late 1800s. At present, east Asia has the fastest-growing ozone precursor emissions. Much of the springtime east Asian pollution is exported eastwards towards western North America. Despite evidence that the exported Asian pollution produces ozone, no previous study has found a significant increase in free tropospheric ozone concentrations above the western USA since measurements began in the late 1970s. Here we compile springtime ozone measurements from many different platforms across western North America. We show a strong increase in springtime ozone mixing ratios during 1995-2008 and we have some additional evidence that a similar rate of increase in ozone mixing ratio has occurred since 1984. We find that the rate of increase in ozone mixing ratio is greatest when measurements are more heavily influenced by direct transport from Asia. Our result agrees with previous modelling studies, which indicate that global ozone concentrations should be increasing during the early part of the twenty-first century as a result of increasing precursor emissions, especially at northern mid-latitudes, with western North America being particularly sensitive to rising Asian emissions. We suggest that the observed increase in springtime background ozone mixing ratio may hinder the USA's compliance with its ozone air quality standard.

  10. An investigation on the origin of regional springtime ozone episodes in the western Mediterranean

    NASA Astrophysics Data System (ADS)

    Kalabokas, Pavlos; Hjorth, Jens; Foret, Gilles; Dufour, Gaëlle; Eremenko, Maxim; Siour, Guillaume; Cuesta, Juan; Beekmann, Matthias

    2017-03-01

    photochemically produced ozone there, resulting in exceedances of the 60 ppb standard.

  11. Tropical tropospheric ozone from total ozone mapping spectrometer by a modified residual method

    NASA Astrophysics Data System (ADS)

    Hudson, Robert D.; Thompson, Anne M.

    1998-09-01

    A modified residual method for deriving time-averaged tropical tropospheric ozone (TTO) from total ozone mapping spectrometer (TOMS) has been refined [cf Kim et al., 1996] and applied to a 2-year period, 1991-1992. This period was selected because of the availability of a unique sonde record at tropical Atlantic and near-Atlantic sites: Natal, Brazil; Ascension Island; and Brazzaville. The essentials of the modified-residual method are (1) Fourier analysis to identify the latitude range for use of the method; (2) use of the wave-like pattern to estimate stratospheric ozone column and a background tropospheric ozone column, which is defined as the amount of ozone expected in the absence of chemical pollution; (3) assumption that the wave-one feature is tropospheric; and (4) the stratospheric and background tropospheric ozone amounts consistent with the constraint of the three station ozonesonde measurements for total tropospheric ozone. An excess ozone (pollution) signal is also derived from TOMS total ozone. Parameters derived from the modified residual method are evaluated with independent data to verify the quality of the TTO. Derived tropical stratospheric column ozone for 1991-1992 agrees very well with the corresponding UARS Microwave Limb Sounder and Stratospheric Aerosol and Gas Experiment records (to within 5 Dobson units (DU) for the latter). Background tropospheric ozone, which exhibits a seasonally in 1991-1992, has a 24±4.8 DU mean value at wave maximum (˜0° longitude) and a 15.2±6.0 DU mean value at 180° longitude. The Atlantic value is remarkably similar to the climatological 26 DU previously inferred from subtropical sondes [Kim et al., 1996; Komhyr et al., 1989]. The ˜5 DU standard deviation is the accuracy of the modified-residual method and is the best that can be achieved given the 15-day averaging of the sondes (1σ = 5.3 DU). The wave-like pattern in 1991-1992 has a semiannual periodicity with zero wave amplitude in June and December.

  12. A phase 2 safety study of accelerated elotuzumab infusion, over less than 1 hour, in combination with lenalidomide and dexamethasone, in patients with multiple myeloma.

    PubMed

    Berenson, James; Manges, Robert; Badarinath, Suprith; Cartmell, Alan; McIntyre, Kristi; Lyons, Roger; Harb, Wael; Mohamed, Hesham; Nourbakhsh, Ali; Rifkin, Robert

    2017-02-18

    Elotuzumab, an immunostimulatory SLAMF7-targeting monoclonal antibody, induces myeloma cell death with minimal effects on normal tissue. In a previous phase 3 study in patients with relapsed/refractory multiple myeloma (RRMM), elotuzumab (10 mg/kg, ∼3-hour infusion), combined with lenalidomide and dexamethasone, demonstrated durable efficacy and acceptable safety; 10% (33/321) of patients had infusion reactions (IRs; Grade 1/2: 29; Grade 3: 4). This phase 2 study (NCT02159365) investigated an accelerated infusion schedule in 70 patients with newly diagnosed multiple myeloma or RRMM. The primary endpoint was cumulative incidence of Grade 3/4 IRs by completion of treatment Cycle 2. Dosing comprised elotuzumab 10 mg/kg intravenously (weekly, Cycles 1-2; biweekly, Cycles 3+), lenalidomide 25 mg (daily, Days 1-21) and dexamethasone (28 mg orally and 8 mg intravenously, weekly, Cycles 1-2; 40 mg orally, weekly, Cycles 3+), in 28-day cycles. Premedication with diphenhydramine, acetaminophen, and ranitidine (or their equivalents) was given as in previous studies. If no IRs occurred, infusion rate was increased in Cycle 1 from 0.5 to 2 mL/min during dose 1 (∼2 hours 50 min duration) to 5 mL/min for the entire infusion by dose 3 and also during all subsequent infusions (∼1-hour duration). Median number of treatment cycles was six. No Grade 3/4 IRs occurred; only one Grade 1 and one Grade 2 IR occurred, both during the first infusion. These data support the safety of a faster infusion of elotuzumab administered over ∼1 hour by the third dose, providing a more convenient alternative dosing option for patients. This article is protected by copyright. All rights reserved.

  13. Ozone Therapy in Dentistry

    PubMed Central

    Domb, William C

    2014-01-01

    Summary The 21st century dental practice is quite dynamic. New treatment protocols and new materials are being developed at a rapid pace. Ozone dental therapy falls into the category of new treatment protocols in dentistry, yet ozone is not new at all. Ozone therapy is already a major treatment modality in Europe, South America and a number of other countries. What is provided here will not be an exhaustive scientific treatise so much as a brief general introduction into what dentists are now doing with ozone therapies and the numerous oral/systemic links that make this subject so important for physicians so that, ultimately, they may serve their patients more effectively and productively. PMID:25363268

  14. Addressing Ozone Layer Depletion

    EPA Pesticide Factsheets

    Access information on EPA's efforts to address ozone layer depletion through regulations, collaborations with stakeholders, international treaties, partnerships with the private sector, and enforcement actions under Title VI of the Clean Air Act.

  15. Ozone Correlative Measurements Workshop

    NASA Technical Reports Server (NTRS)

    Hilsenrath, E. (Editor)

    1985-01-01

    A study was conducted to determine the necessary parameters for the correlation of data on Earth ozone. Topics considered were: (1) measurement accuracy; (2) equipment considerations (SBUV); and (3) ground based measurements to support satellite data.

  16. Clean Cities ozone air quality attainment and maintenance strategies that employ alternative fuel vehicles, with special emphasis on natural gas and propane

    SciTech Connect

    Santini, D.J.; Saricks, C.L.

    1998-08-04

    -fueled for gasoline-fueled heavy-duty vehicles. Finally, it raises and expands on the relevance of AFVs and their deployment to some other provisions embedded in EPA`s current guidance for implementing 1-hour NAAQS--standards which currently remain in effect--as tools to provide immediate reductions in ozone, without waiting for promised future clean technologies.

  17. The ozone backlash

    SciTech Connect

    Taubes, G.

    1993-06-11

    While evidence for the role of chlorofluorocarbons in ozone depletion grows stronger, researchers have recently been subjected to vocal public criticism of their theories-and their motives. Their understanding of the mechanisms of ozone destruction-especially the annual ozone hole that appears in the Antarctic-has grown stronger, yet everywhere they go these days, they seem to be confronted by critics attacking their theories as baseless. For instance, Rush Limbaugh, the conservative political talk-show host and now-best-selling author of The Way Things Ought to Be, regularly insists that the theory of ozone depletion by CFCs is a hoax: bladerdash and poppycock. Zoologist Dixy Lee Ray, former governor of the state of Washington and former head of the Atomic Energy Commission, makes the same argument in her book, Trashing the Planet. The Wall Street Journal and National Review have run commentaries by S. Fred Singer, a former chief scientists for the Department of Transportation, purporting to shoot holes in the theory of ozone depletion. Even the June issue of Omni, a magazine with a circulation of more than 1 million that publishes a mixture of science and science fiction, printed a feature article claiming to expose ozone research as a politically motivated scam.

  18. Ensuring equity in reducing regional ozone

    SciTech Connect

    Harper, S.F.

    1996-12-31

    Substantial progress has been made in improving air quality throughout the US over the last 25 years. Nonetheless, ozone nonattainment remains a concern, especially in california and the eastern US. What is especially clear fin the eastern half of the US is that the long-distance transport of ozone and its precursors from one area to another may make it impossible for some areas to meet the federal health standard by taking actions only in their jurisdiction. The air coming into some metropolitan areas already is near or above the standard, even before local pollution is added. The Ozone Transport Assessment Group (OTAG) has been established as a cooperative effort among 37 states, EPA, and many private interests to address the phenomenon of regional ozone pollution in the eastern half of the US. Discussions about how to achieve this goal also have focused on the concept of equity as a consideration in shaping the best strategy and suite of specific control programs. These discussions have been conceptual to date; no concrete definition of equity has emerged. The purpose of this paper is to suggest some key elements of what equity might mean in the OTAG context.

  19. Treatment of Ammonia Nitrogen Wastewater in Low Concentration by Two-Stage Ozonization.

    PubMed

    Luo, Xianping; Yan, Qun; Wang, Chunying; Luo, Caigui; Zhou, Nana; Jian, Chensheng

    2015-09-23

    Ammonia nitrogen wastewater (about 100 mg/L) was treated by two-stage ozone oxidation method. The effects of ozone flow rate and initial pH on ammonia removal were studied, and the mechanism of ammonia nitrogen removal by ozone oxidation was discussed. After the primary stage of ozone oxidation, the ammonia removal efficiency reached 59.32% and pH decreased to 6.63 under conditions of 1 L/min ozone flow rate and initial pH 11. Then, the removal efficiency could be over 85% (the left ammonia concentration was lower than 15 mg/L) after the second stage, which means the wastewater could have met the national discharge standards of China. Besides, the mechanism of ammonia removal by ozone oxidation was proposed by detecting the products of the oxidation: ozone oxidation directly and ·OH oxidation; ammonia was mainly transformed into NO₃(-)-N, less into NO₂(-)-N, not into N₂.

  20. The Ozone Problem | Ground-level Ozone | New England | US ...

    EPA Pesticide Factsheets

    2017-04-10

    Many factors impact ground-level ozone development, including temperature, wind speed and direction, time of day, and driving patterns. Due to its dependence on weather conditions, ozone is typically a summertime pollutant and a chief component of summertime smog.

  1. Ozone risk for crops and pastures in present and future climates

    NASA Astrophysics Data System (ADS)

    Fuhrer, Jürg

    2009-02-01

    most at risk from ozone in a future climate and to set robust effect-based ozone standards.

  2. The ASSET intercomparison of ozone analyses: method and first results

    NASA Astrophysics Data System (ADS)

    Geer, A. J.; Lahoz, W. A.; Bekki, S.; Bormann, N.; Errera, Q.; Eskes, H. J.; Fonteyn, D.; Jackson, D. R.; Juckes, M. N.; Massart, S.; Peuch, V.-H.; Rharmili, S.; Segers, A.

    2006-06-01

    This paper examines 11 sets of ozone analyses from 7 different data assimilation systems. Two are numerical weather prediction (NWP) systems based on general circulation models (GCMs); the other five use chemistry transport models (CTMs). These systems contain either linearised or detailed ozone chemistry, or no chemistry at all. In most analyses, MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) ozone data are assimilated. Two examples assimilate SCIAMACHY (Scanning Imaging Absorption Spectrometer for Atmospheric Chartography) observations. The analyses are compared to independent ozone observations covering the troposphere, stratosphere and lower mesosphere during the period July to November 2003. Through most of the stratosphere (50 hPa to 1 hPa), biases are usually within ±10% and standard deviations less than 10% compared to ozonesondes and HALOE (Halogen Occultation Experiment). Biases and standard deviations are larger in the upper-troposphere/lower-stratosphere, in the troposphere, the mesosphere, and the Antarctic ozone hole region. In these regions, some analyses do substantially better than others, and this is mostly due to differences in the models. At the tropical tropopause, many analyses show positive biases and excessive structure in the ozone fields, likely due to known deficiencies in assimilated tropical wind fields and a degradation in MIPAS data at these levels. In the southern hemisphere ozone hole, only the analyses which correctly model heterogeneous ozone depletion are able to reproduce the near-complete ozone destruction over the pole. In the upper-stratosphere and mesosphere (above 5 hPa), some ozone photochemistry schemes caused large but easily remedied biases. The diurnal cycle of ozone in the mesosphere is not captured, except by the one system that includes a detailed treatment of mesospheric chemistry. In general, similarly good results are obtained no matter what the assimilation method (Kalman filter, three or

  3. Recovery of the Ozone Layer: The Ozone Depleting Gas Index

    NASA Astrophysics Data System (ADS)

    Hofmann, David J.; Montzka, Stephen A.

    2009-01-01

    The stratospheric ozone layer, through absorption of solar ultraviolet radiation, protects all biological systems on Earth. In response to concerns over the depletion of the global ozone layer, the U.S. Clean Air Act as amended in 1990 mandates that NASA and NOAA monitor stratospheric ozone and ozone-depleting substances. This information is critical for assessing whether the Montreal Protocol on Substances That Deplete the Ozone Layer, an international treaty that entered into force in 1989 to protect the ozone layer, is having its intended effect of mitigating increases in harmful ultraviolet radiation. To provide the information necessary to satisfy this congressional mandate, both NASA and NOAA have instituted and maintained global monitoring programs to keep track of ozone-depleting gases as well as ozone itself. While data collected for the past 30 years have been used extensively in international assessments of ozone layer depletion science, the language of scientists often eludes the average citizen who has a considerable interest in the health of Earth's protective ultraviolet radiation shield. Are the ozone-destroying chemicals declining in the atmosphere? When will these chemicals decline to pre-ozone hole levels so that the Antarctic ozone hole might disappear? Will this timing be different in the stratosphere above midlatitudes?

  4. Children's Models of the Ozone Layer and Ozone Depletion.

    ERIC Educational Resources Information Center

    Christidou, Vasilia; Koulaidis, Vasilis

    1996-01-01

    The views of 40 primary students on ozone and its depletion were recorded through individual, semi-structured interviews. The data analysis resulted in the formation of a limited number of models concerning the distribution and role of ozone in the atmosphere, the depletion process, and the consequences of ozone depletion. Identifies five target…

  5. CONTRIBUTION TO INDOOR OZONE LEVELS OF AN OZONE GENERATOR

    EPA Science Inventory

    This report gives results of a study of a commonly used commercially available ozone generator, undertaken to determine its impact on indoor ozone levels. xperiment were conducted in a typical mechanically ventilated office and in a test house. he generated ozone and the in-room ...

  6. Achievements in Stratospheric Ozone Protection

    EPA Pesticide Factsheets

    This report describes achievements in protecting the ozone layer, the benefits of these achievements, and strategies involved (e.g., using alternatives to ozone-depleting substances, phasing out harmful substances, and creating partnerships).

  7. Air Quality Guide for Ozone

    MedlinePlus

    Local Air Quality Conditions Zip Code: State : My Current Location Air Quality Guide for Ozone Ground-level ozone is one ... exposure and protect your health. For your local air quality, visit www.airnow.gov View or print guide ...

  8. Ozone Minimums, 1979 to 2013

    NASA Video Gallery

    Minimum concentration of ozone in the southern hemisphere for each year from 1979-2013 (there is no data from 1995). Each image is the day of the year with the lowest concentration of ozone. A grap...

  9. Health Effects of Ozone Pollution

    EPA Pesticide Factsheets

    Inhaling ozone can cause coughing, shortness of breath, worse asthma or bronchitis symptoms, and irritation and damage to airways.You can reduce your exposure to ozone pollution by checking air quality where you live.

  10. "OZONE SOURCE APPORTIONMENT IN CMAQ'

    EPA Science Inventory

    Ozone source attribution has been used to support various policy purposes including interstate transport (Cross State Air Pollution Rule) by U.S. EPA and ozone nonattainment area designations by State agencies. Common scientific applications include tracking intercontinental tran...

  11. Ozone concentrations near roadways - results of a field study in Cincinnati, Ohio

    SciTech Connect

    Johnson, T.; Weaver, M.; Mozier, J.

    1997-12-31

    In evaluating alternative versions of the National Ambient Air Quality Standard (NAAQS) for ozone, the U.S. Environmental Protection Agency uses the probabilistic NAAQS Exposure Model (pNEM/O3) to estimate the relative ozone exposures of urban populations. This model simulates the movement of susceptible population groups through various microenvironmental (ME) settings and uses ambient monitoring data and ME adjustments to estimate a sequence of exposures for each group. One ME is defined as {open_quotes}outdoors near roadway.{close_quotes} To obtain an improved modeling database for this ME, researchers conducted a two-phase field study in Cincinnati, Ohio during the summers of 1994 and 1995. Technicians measured ozone and nitric oxide from automobile exhaust at upwind and downwind locations near a variety of roadways in areas with historically high ozone levels. During the 1995 phase, measurements were taken at 2 and 10-meter elevations along a downwind pathway at right angles to each roadway. Statistical analyses of the ozone concentrations measured at these locations indicated that height above the ground was always a very significant predictor of ozone, with ozone levels at 10 m above the ground tending to be higher than those at 2 m. Ozone varied significantly as a quadratic function of distance from the road at 2 m, but not at 10 m. Downwind ozone decreased with increasing levels of downwind NO, consistent with the hypothesis that ozone is scavenged by NO from automobile exhaust. Downwind ozone levels increased with increasing temperature.

  12. Mars ozone: Mariner 9 revisited

    NASA Technical Reports Server (NTRS)

    Lindner, Bernhard Lee

    1994-01-01

    The efficacy of the UV spectroscopy technique used by Mariner 9 to remotely measure ozone abundance at Mars is discussed. Previously-inferred ozone abundances could be underestimated by as much as a factor of 3, and much of the observed variability in the ozone abundance could be due to temporal and spatial variability in cloud and dust amount.

  13. Ames ER-2 ozone measurements

    NASA Technical Reports Server (NTRS)

    Pearson, R., Jr.; Vedder, James F.; Starr, W. L.

    1990-01-01

    The objective of this research is to study ozone (O3) in the stratosphere. Measurements of the ozone mixing ratio at 1 s intervals are obtained with an ultraviolet photometer which flies on the ER-2 aircraft. The photometer determines the amount of ozone in air by measuring the transmission of ultraviolet light through a fixed path with and without ambient O3 present.

  14. ADEOS Total Ozone Mapping Spectrometer (TOMS) Data Products User's Guide

    NASA Technical Reports Server (NTRS)

    Krueger, A.; Bhartia, P. K.; McPeters, R.; Herman, J.; Wellemeyer, C.; Jaross, G.; Seftor, C.; Torres, O.; Labow, G.; Byerly, W.; Moy, L.; Taylor, S.; Swissler, T.; Cebula, R.

    1998-01-01

    Two data products from the Total Ozone Mapping Spectrometer (ADEOS/TOMS) have been archived at the Distributed Active Archive Center, in the form of Hierarchical Data Format files. The ADEOS/ TOMS began taking measurements on September 11, 1996, and ended on June 29, 1997. The instrument measured backscattered Earth radiance and incoming solar irradiance; their ratio was used in ozone retrievals. Changes in the reflectivity of the solar diffuser used for the irradiance measurement were monitored using a carousel of three diffusers, each exposed to the degrading effects of solar irradiation at different rates. The algorithm to retrieve total column ozone compares measured Earth radiances at sets of three wavelengths with radiances calculated for different total ozone values, solar zenith angles, and optical paths. The initial error in the absolute scale for TOMS total ozone is 3 percent, the one standard deviation random error is 2 percent, and the drift is less than 0.5 percent over the 9-month data record. The Level 2 product contains the measured radiances, the derived total ozone amount, and reflectivity information for each scan position. The Level 3 product contains daily total ozone and reflectivity in a 1-degree latitude by 1.25 degrees longitude grid. The Level 3 files containing estimates of UVB at the Earth surface and tropospheric aerosol information will also be available. Detailed descriptions of both HDF data files and the CDROM product are provided.

  15. SAGE II Ozone Analysis

    NASA Technical Reports Server (NTRS)

    Cunnold, Derek; Wang, Ray

    2002-01-01

    Publications from 1999-2002 describing research funded by the SAGE II contract to Dr. Cunnold and Dr. Wang are listed below. Our most recent accomplishments include a detailed analysis of the quality of SAGE II, v6.1, ozone measurements below 20 km altitude (Wang et al., 2002 and Kar et al., 2002) and an analysis of the consistency between SAGE upper stratospheric ozone trends and model predictions with emphasis on hemispheric asymmetry (Li et al., 2001). Abstracts of the 11 papers are attached.

  16. Physicochemical patterns of ozone absorption by wood

    NASA Astrophysics Data System (ADS)

    Mamleeva, N. A.; Lunin, V. V.

    2016-11-01

    Results from studying aspen and pine wood ozonation are presented. The effect the concentration of ozone, the reagent residence time, and the content of water in a sample of wood has on ozone consumption rate and ozone demand are analyzed. The residence time is shown to determine the degree of ozone conversion degree and the depth of substrate destruction. The main patterns of ozone absorption by wood with different moisture content are found. Ways of optimizing the ozonation of plant biomass are outlined.

  17. Total Ozone Prediction: Stratospheric Dynamics

    NASA Technical Reports Server (NTRS)

    Jackman, Charles H.; Kawa, S. Ramdy; Douglass, Anne R.

    2003-01-01

    The correct prediction of total ozone as a function of latitude and season is extremely important for global models. This exercise tests the ability of a particular model to simulate ozone. The ozone production (P) and loss (L) will be specified from a well- established global model and will be used in all GCMs for subsequent prediction of ozone. This is the "B-3 Constrained Run" from M&MII. The exercise mostly tests a model stratospheric dynamics in the prediction of total ozone. The GCM predictions will be compared and contrasted with TOMS measurements.

  18. Precision ozone vapor pressure measurements

    NASA Technical Reports Server (NTRS)

    Hanson, D.; Mauersberger, K.

    1985-01-01

    The vapor pressure above liquid ozone has been measured with a high accuracy over a temperature range of 85 to 95 K. At the boiling point of liquid argon (87.3 K) an ozone vapor pressure of 0.0403 Torr was obtained with an accuracy of + or - 0.7 percent. A least square fit of the data provided the Clausius-Clapeyron equation for liquid ozone; a latent heat of 82.7 cal/g was calculated. High-precision vapor pressure data are expected to aid research in atmospheric ozone measurements and in many laboratory ozone studies such as measurements of cross sections and reaction rates.

  19. Ozone pollution in China: A review of concentrations, meteorological influences, chemical precursors, and effects.

    PubMed

    Wang, Tao; Xue, Likun; Brimblecombe, Peter; Lam, Yun Fat; Li, Li; Zhang, Li

    2017-01-01

    High concentrations of ozone in urban and industrial regions worldwide have long been a major air quality issue. With the rapid increase in fossil fuel consumption in China over the past three decades, the emission of chemical precursors to ozone-nitrogen oxides and volatile organic compounds-has increased sharply, surpassing that of North America and Europe and raising concerns about worsening ozone pollution in China. Historically, research and control have prioritized acid rain, particulate matter, and more recently fine particulate matter (PM2.5). In contrast, less is known about ozone pollution, partly due to a lack of monitoring of atmospheric ozone and its precursors until recently. This review summarizes the main findings from published papers on the characteristics and sources and processes of ozone and ozone precursors in the boundary layer of urban and rural areas of China, including concentration levels, seasonal variation, meteorology conducive to photochemistry and pollution transport, key production and loss processes, ozone dependence on nitrogen oxides and volatile organic compounds, and the effects of ozone on crops and human health. Ozone concentrations exceeding the ambient air quality standard by 100-200% have been observed in China's major urban centers such as Jing-Jin-Ji, the Yangtze River delta, and the Pearl River delta, and limited studies suggest harmful effect of ozone on human health and agricultural corps; key chemical precursors and meteorological conditions conductive to ozone pollution have been investigated, and inter-city/region transport of ozone is significant. Several recommendations are given for future research and policy development on ground-level ozone.

  20. Approach to forecasting daily maximum ozone levels in St. Louis

    NASA Technical Reports Server (NTRS)

    Prior, E. J.; Schiess, J. R.; Mcdougal, D. S.

    1981-01-01

    Measurements taken in 1976 from the St. Louis Regional Air Pollution Study (RAPS) data base, conducted by EPA, were analyzed to determine an optimum set of air-quality and meteorological variables for predicting maximum ozone levels for each day in 1976. A 'leaps and bounds' regression analysis was used to identify the best subset of variables. Three particular variables, the 9 a.m. ozone level, the forecasted maximum temperature, and the 6-9 a.m. averaged wind speed, have useful forecasting utility. The trajectory history of air masses entering St. Louis was studied, and it was concluded that transport-related variables contribute to the appearance of very high ozone levels. The final empirical forecast model predicts the daily maximum ozone over 341 days with a standard deviation of 11 ppb, which approaches the estimated error.

  1. Winter rain and summer ozone: a predictive relationship.

    PubMed

    Sandberg, J S; Basso, M J; Okin, B A

    1978-06-02

    Insights from dendrochronology have provided a new seasonal predictor for air pollution meteorology. In the San Francisco Bay Area summer ozone excesses over the federal ozone standard are correlated (correlation coefficient r = .87) with precipitation for the two preceding winters, a factor related to tree-ring width in a precipitation-stressed climate. The hypothesis that reactive hydrocarbon emissions from vegetative biomass affects these ozone excesses was supported by a similar correlation between summer hydrocarbon average maximums and the two-winter precipitation factor, reaching r = .88 at suburban stations. A weak tendency for hot summers to follow wet winters (in 16 years of California data) explains only a minor part of the ozone-rain relationship in multiple correlations.

  2. Ozone and other air pollutants from photocopying machines

    SciTech Connect

    Hansen, T.B.; Andersen, B.

    1986-10-01

    The ozone emission from 69 different photocopying machines was determined by a described standard procedure. The emission rates were in the range of 0 to 1350 ..mu..g/min. The concentration in the breathing zone of 19 operators was found to be between less than or equal to 0.001 and 0.15 ppm. Technical conditions for the amount of ozone generated by photocopiers are described, as well as conditions for the rate of decomposition of ozone. The efficiencies of three different types of ozone filters were tested: activated carbon granulate; polyester; and polyurethane impregnated with activated carbon. Other pollutants levels from the copying process (selenium and cadmium) were less than the limit of detection. Dust concentrations (toner) in the air exhausted from photocopies were found in the same magnitude as normal dust concentrations in offices. Vapors from the resin in the toner were often present in concentrations and gave operators an unpleasant feeling.

  3. High efficiency ozone generation system

    SciTech Connect

    Karlson, E.L.

    1990-01-09

    This final report entails research prepared to verify the workings and the efficiency of producing ozone with the ELK'' Ozone Generator, which operates at an elevated gas pressure of up to 20 MPA (3000 psi) and is an improvement of the corona discharge ozone generator. The increased pressure produces an increase in the density of oxygen gas fed into the generator. This, in turn, leads to an increased yield of ozone in the ozone oxygen gas mixture leaving the generator. The design of this new ozone generator incorporates a novel positioning of the dielectric to preserve its mechanical integrity at high operating pressures and also incorporates a novel heat removal technique. A large number of ozone production runs have been made at different pressures. Large populations of data such as, temperature points throughout the generator, gas flow, cooling water flow parameters, operating gas pressure, ozone concentration, and data on the dielectric cooling, have been compiled and fed into our computer. This new data indicates not only that high pressures used in a controlled fashion will produce more ozone per watt hour but also indicates what problems exist when pressures are increased, such as the generation of high temperatures not only in the area of ozone generation but within the dielectric. The data also shows the necessary residence time for maximum ozone production at a particular pressure, voltage, temperature and electrode spacing. 14 refs., 22 figs.

  4. Assimilation of Satellite Ozone Observations

    NASA Technical Reports Server (NTRS)

    Stajner, I.; Winslow, N.; Wargan, K.; Hayashi, H.; Pawson, S.; Rood, R.

    2003-01-01

    This talk will discuss assimilation of ozone data from satellite-borne instruments. Satellite observations of ozone total columns and profiles have been measured by a series of Total Ozone Mapping Spectrometer (TOMS), Solar Backscatter Ultraviolet (SBUV) instruments, and more recently by the Global Ozone Monitoring Experiment. Additional profile data are provided by instruments on NASA's Upper Atmosphere Research Satellite and by occultation instruments on other platforms. Instruments on Envisat' and future EOS Aura satellite will supply even more comprehensive data about the ozone distribution. Satellite data contain a wealth of information, but they do not provide synoptic global maps of ozone fields. These maps can be obtained through assimilation of satellite data into global chemistry and transport models. In the ozone system at NASA's Data Assimilation Office (DAO) any combination of TOMS, SBUV, and Microwave Limb sounder (MLS) data can be assimilated. We found that the addition of MLS to SBUV and TOMS data in the system helps to constrain the ozone distribution, especially in the polar night region and in the tropics. The assimilated ozone distribution in the troposphere and lower stratosphere is sensitive also to finer changes in the SBUV and TOMS data selection and to changes in error covariance models. All results are established by comparisons of assimilated ozone with independent profiles from ozone sondes and occultation instruments.

  5. Updated ozone absorption cross section will reduce air quality compliance

    NASA Astrophysics Data System (ADS)

    Sofen, E. D.; Evans, M. J.; Lewis, A. C.

    2015-07-01

    Photometric ozone measurements rely upon an accurate value of the ozone absorption cross section at 253.65 nm. This has recently been reevaluated by Viallon et al. (2015) as 1.8 % smaller than the accepted value (Hearn, 1961) used for the preceding fifty years. Thus, ozone measurements that applied the older cross section systematically underestimate the amount of ozone in air. We correct the reported historical surface data from North America and Europe and find that this modest change in cross section has a significant impact on the number of locations that are out of compliance with air quality regulations if the air quality standards remain the same. We find 18, 23, and 20 % increases in the number of sites that are out of compliance with current US, Canadian, and European ozone air quality health standards for the year 2012. Should the new cross section value be applied, it would impact attainment of air quality standards and compliance with relevant clean air acts, unless the air quality target values themselves were also changed proportionately. We draw attention to how a small change in gas metrology has a global impact on attainment and compliance with legal air quality standards. We suggest that further laboratory work to evaluate the new cross section is needed and suggest three possible technical and policy responses should the new cross section be adopted.

  6. Updated ozone absorption cross section will reduce air quality compliance

    NASA Astrophysics Data System (ADS)

    Sofen, E. D.; Evans, M. J.; Lewis, A. C.

    2015-12-01

    Photometric ozone measurements rely upon an accurate value of the ozone absorption cross section at 253.65 nm. This has recently been re-evaluated by Viallon et al. (2015) as 1.8 % smaller than the accepted value (Hearn, 1961) used for the preceding 50 years. Thus, ozone measurements that applied the older cross section systematically underestimate the amount of ozone in air. We correct the reported historical surface data from North America and Europe and find that this modest change in cross section has a significant impact on the number of locations that are out of compliance with air quality regulations if the air quality standards remain the same. We find 18, 23, and 20 % increases in the number of sites that are out of compliance with current US, Canadian, and European ozone air quality health standards for the year 2012. Should the new cross-section value be applied, it would impact attainment of air quality standards and compliance with relevant clean air acts, unless the air quality target values themselves were also changed proportionately. We draw attention to how a small change in gas metrology has a global impact on attainment and compliance with legal air quality standards. We suggest that further laboratory work to evaluate the new cross section is needed and suggest three possible technical and policy responses should the new cross section be adopted.

  7. Ozone Cross-Section Measurement by Gas Phase Titration.

    PubMed

    Viallon, Joële; Moussay, Philippe; Flores, Edgar; Wielgosz, Robert I

    2016-11-01

    Elevated values of ground-level ozone damage health, vegetation, and building materials and are the subject of air quality regulations. Levels are monitored by networks using mostly ultraviolet (UV) absorption instruments, with traceability to standard reference photometers, relying on the UV absorption of ozone at the 253.65 nm line of mercury. We have redetermined the ozone cross-section at this wavelength based on gas phase titration (GPT) measurements. This is a well-known chemical method using the reaction of ozone (O3) with nitrogen monoxide (NO) resulting in nitrogen dioxide (NO2) and oxygen (O2). The BIPM GPT facility uses state-of-the-art flow measurement, chemiluminescence for NO concentration measurements, a cavity phase shift analyzer (CAPS) for NO2 measurements, and a UV ozone analyzer. The titration experiment is performed over the concentration range 100-500 nmol/mol, with NO and NO2 reactants/calibrants diluted down from standards with nominal mole fractions of 50 μmol/mol. Accurate measurements of NO, NO2, and O3 mole fractions allow the calculation of ozone absorption cross section values at 253.65 nm, and we report a value of 11.24 × 10(-18) cm(2) molecule(-1) with a relative expanded uncertainty of 1.8% (coverage factor k = 2) based on nitrogen monoxide titration values and a value of 11.22 × 10(-18) cm(2) molecule(-1) with a relative expanded uncertainty of 1.4% (coverage factor k = 2) based on nitrogen dioxide titration values. The excellent agreement between these values and recently published absorption cross-section measurements directly on pure ozone provide strong evidence for revising the conventionally accepted value of ozone cross section at 253.65 nm.

  8. Ozone decomposing filter

    SciTech Connect

    Simandl, R.F.; Brown, J.D.; Whinnery, L.L. Jr.

    1999-11-02

    In an improved ozone decomposing air filter carbon fibers are held together with a carbonized binder in a perforated structure. The structure is made by combining rayon fibers with gelatin, forming the mixture in a mold, freeze-drying, and vacuum baking.

  9. The Ozone Show.

    ERIC Educational Resources Information Center

    Mathieu, Aaron

    2000-01-01

    Uses a talk show activity for a final assessment tool for students to debate about the ozone hole. Students are assessed on five areas: (1) cooperative learning; (2) the written component; (3) content; (4) self-evaluation; and (5) peer evaluation. (SAH)

  10. Ozone decomposing filter

    DOEpatents

    Simandl, Ronald F.; Brown, John D.; Whinnery, Jr., LeRoy L.

    1999-01-01

    In an improved ozone decomposing air filter carbon fibers are held together with a carbonized binder in a perforated structure. The structure is made by combining rayon fibers with gelatin, forming the mixture in a mold, freeze-drying, and vacuum baking.

  11. Dobson ozone spectrophotometer modification.

    NASA Technical Reports Server (NTRS)

    Komhyr, W. D.; Grass, R. D.

    1972-01-01

    Description of a modified version of the Dobson ozone spectrophotometer in which several outdated electronic design features have been replaced by circuitry embodying more modern design concepts. The resulting improvement in performance characteristics has been obtained without changing the principle of operation of the original instrument.

  12. Ozone, CFCs and aerosols.

    PubMed

    1989-07-01

    Chlorofluorocarbons (CFCs) are, from the chemist's point of view, unique compounds with very valuable properties. They are inert, cheap and stable. But they also have devastating effects on the environment, destroying the ozone layer and adding to global warming or the greenhouse effect.

  13. Ozone Layer Educator's Guide.

    ERIC Educational Resources Information Center

    Environmental Protection Agency, Washington, DC.

    This guide has been developed through a collaborative effort involving the U.S. Environmental Protection Agency (EPA), the National Oceanic and Atmospheric Administration (NOAA), and the National Aeronautics and Space Administration (NASA). It is part of an ongoing commitment to ensure that the results of scientific research on ozone depletion are…

  14. Ozone and Cavitation Combination

    NASA Astrophysics Data System (ADS)

    Carreon, Ernestina; Traversoni, Leonardo

    2009-09-01

    From laboratory measurements it is well known that the addition of ozone and cavitation enhances the properties of both, understanding for that the ones related to disinfection and carbon removal from waste water. This paper shows modeling of such phenomena that gives some light to the understanding of it and also provides the opportunity to improve the effectiveness of the current procedures.

  15. Validation of OMI total ozone retrievals from the SAO ozone profile algorithm and three operational algorithms with Brewer measurements

    NASA Astrophysics Data System (ADS)

    Bak, J.; Liu, X.; Kim, J. H.; Chance, K.; Haffner, D. P.

    2015-01-01

    The accuracy of total ozone computed from the Smithsonian Astrophysical Observatory (SAO) optimal estimation (OE) ozone profile algorithm (SOE) applied to the Ozone Monitoring Instrument (OMI) is assessed through comparisons with ground-based Brewer spectrometer measurements from 2005 to 2008. We also compare the three OMI operational ozone products, derived from the NASA Total Ozone Mapping Spectrometer (TOMS) algorithm, the KNMI (Royal Netherlands Meteorological Institute) differential optical absorption spectroscopy (DOAS) algorithm, and KNMI's Optimal Estimation (KOE) algorithm. The best agreement is observed between SAO and Brewer, with a mean difference of within 1% at most individual stations. The KNMI OE algorithm systematically overestimates Brewer total ozone by 2% at low and mid-latitudes and 5% at high latitudes while the TOMS and DOAS algorithms underestimate it by ~1.65% on average. Standard deviations of ~1.8% are calculated for both SOE and TOMS, but DOAS and KOE have higher values of 2.2% and 2.6%, respectively. The stability of the SOE algorithm is found to have insignificant dependence on viewing geometry, cloud parameters, or total ozone column. In comparison, the KOE-Brewer differences are significantly correlated with solar and viewing zenith angles and show significant deviations depending on cloud parameters and total ozone amount. The TOMS algorithm exhibits similar stability to SOE with respect to viewing geometry and total column ozone, but has stronger cloud parameter dependence. The dependence of DOAS on observational geometry and geophysical conditions is marginal compared to KOE, but is distinct compared to the SOE and TOMS algorithms. Comparisons of all four OMI products with Brewer show no apparent long-term drift, but seasonal features are evident, especially for KOE and TOMS. The substantial differences in the KOE vs. SOE algorithm performance cannot be sufficiently explained by the use of soft calibration (in SOE) and the use of

  16. 40 CFR 51.918 - Can any SIP planning requirements be suspended in 8-hour ozone nonattainment areas that have air...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... suspended in 8-hour ozone nonattainment areas that have air quality data that meets the NAAQS? 51.918... 8-hour Ozone National Ambient Air Quality Standard § 51.918 Can any SIP planning requirements be suspended in 8-hour ozone nonattainment areas that have air quality data that meets the NAAQS? Upon...

  17. 40 CFR 51.918 - Can any SIP planning requirements be suspended in 8-hour ozone nonattainment areas that have air...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... suspended in 8-hour ozone nonattainment areas that have air quality data that meets the NAAQS? 51.918... 8-hour Ozone National Ambient Air Quality Standard § 51.918 Can any SIP planning requirements be suspended in 8-hour ozone nonattainment areas that have air quality data that meets the NAAQS? Upon...

  18. 40 CFR 51.918 - Can any SIP planning requirements be suspended in 8-hour ozone nonattainment areas that have air...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... suspended in 8-hour ozone nonattainment areas that have air quality data that meets the NAAQS? 51.918... 8-hour Ozone National Ambient Air Quality Standard § 51.918 Can any SIP planning requirements be suspended in 8-hour ozone nonattainment areas that have air quality data that meets the NAAQS? Upon...

  19. 40 CFR 51.918 - Can any SIP planning requirements be suspended in 8-hour ozone nonattainment areas that have air...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... suspended in 8-hour ozone nonattainment areas that have air quality data that meets the NAAQS? 51.918... 8-hour Ozone National Ambient Air Quality Standard § 51.918 Can any SIP planning requirements be suspended in 8-hour ozone nonattainment areas that have air quality data that meets the NAAQS? Upon...

  20. 40 CFR 51.918 - Can any SIP planning requirements be suspended in 8-hour ozone nonattainment areas that have air...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... suspended in 8-hour ozone nonattainment areas that have air quality data that meets the NAAQS? 51.918... 8-hour Ozone National Ambient Air Quality Standard § 51.918 Can any SIP planning requirements be suspended in 8-hour ozone nonattainment areas that have air quality data that meets the NAAQS? Upon...

  1. Air Quality Criteria for Ozone and Related Photochemical Oxidants (Final Report, 2006)

    EPA Science Inventory

    In February 2006, EPA released the final document, Air Quality Criteria for Ozone and Other Photochemical Oxidants. Tropospheric or surface-level ozone (O3) is one of six major air pollutants regulated by National Ambient Air Quality Standards (NAAQS) under the U.S...

  2. Formation and transport of secondary air pollutants: ozone and aerosols in the St. Louis urban plume.

    PubMed

    White, W H; Anderson, J A; Blumenthal, D L; Husar, R B; Gillani, N V; Husar, J D; Wilson, W E

    1976-10-08

    Emissions from metropolitan St. Louis caused reduced visibilities and concentrations of ozone in excess of the federal ambient standard (0.08 part per million) 160 kilometers or more downwind of the city on 18 July 1975. Atmospheric production of ozone and visibility-reducing aerosols continues long after their primary precursors have been diluted to low concentrations.

  3. Development of a sensitive passive sampler using indigotrisulfonate for the determination of tropospheric ozone.

    PubMed

    Garcia, Gabriel; Allen, Andrew George; Cardoso, Arnaldo Alves

    2010-06-01

    A new sampling and analytical design for measurement of ambient ozone is presented. The procedure is based on ozone absorption and decoloration (at 600 nm) of indigotrisulfonate dye, where ozone adds itself across the carbon-carbon double bond of the indigo. A mean relative standard deviation of 8.6% was obtained using samplers exposed in triplicate, and a correlation coefficient (r) of 0.957 was achieved in parallel measurements using the samplers and a commercial UV ozone instrument. The devices were evaluated in a measurement campaign, mapping spatial and temporal trends of ozone concentrations in a region of southeast Brazil strongly influenced by seasonal agricultural biomass burning, with associated emissions of ozone precursors. Ozone concentrations were highest in rural areas and lowest at an urban site, due to formation during downwind transport and short-term depletion due to titration with nitric oxide. Ozone concentrations showed strong seasonal trends, due to the influences of precursor emissions, relative humidity and solar radiation intensity. Advantages of the technique include ease and speed of use, the ready availability of components, and excellent sensitivity. Achievable temporal resolution of ozone concentrations is 8 hours at an ambient ozone concentration of 3.8 ppb, or 2 hours at a concentration of 15.2 ppb.

  4. Removal of nalidixic acid and its degradation products by an integrated MBR-ozonation system.

    PubMed

    Pollice, A; Laera, G; Cassano, D; Diomede, S; Pinto, A; Lopez, A; Mascolo, G

    2012-02-15

    Chemical-biological degradation of a widely spread antibacterial (nalidixic acid) was successfully obtained by an integrated membrane bioreactor (MBR)-ozonation process. The composition of the treated solution simulated the wastewater from the production of the target pharmaceutical, featuring high salinity and a relevant concentration of sodium acetate. Aim of treatment integration was to exploit the synergistic effects of chemical oxidation and bioprocesses, by adopting the latter to remove most of the COD and the ozonation biodegradable products. Integration was achieved by placing ozonation in the recirculation stream of the bioreactor effluent. The recirculation flow rate was three-fold the MBR feed, and the performance of the integrated system was compared to the standard polishing configuration (single ozonation step after the MBR). Results showed that the introduction of the ozonation step did not cause relevant drawbacks to both biological and filtration processes. nalidixic acid passed undegraded through the MBR and was completely removed in the ozonation step. Complete degradation of most of the detected ozonation products was better achieved with the integrated MBR-ozonation process than using the sequential treatment configuration, i.e. ozone polishing after MBR, given the same ozone dosage.

  5. Evaluation of ozone emissions and exposures from consumer products and home appliances.

    PubMed

    Zhang, Q; Jenkins, P L

    2017-03-01

    Ground-level ozone can cause serious adverse health effects and environmental impacts. This study measured ozone emissions and impacts on indoor ozone levels and associated exposures from 17 consumer products and home appliances that could emit ozone either intentionally or as a by-product of their functions. Nine products were found to emit measurable ozone, one up to 6230 ppb at a distance of 5 cm (2 inches). One use of these products increased room ozone concentrations by levels up to 106 ppb (mean, from an ozone laundry system) and personal exposure concentrations of the user by 12-424 ppb (mean). Multiple cycles of use of one fruit and vegetable washer increased personal exposure concentrations by an average of 2550 ppb, over 28 times higher than the level of the 1-h California Ambient Air Quality Standard for ozone (0.09 ppm). Ozone emission rates ranged from 1.6 mg/h for a refrigerator air purifier to 15.4 mg/h for a fruit and vegetable washer. The use of some products was estimated to contribute up to 87% of total daily exposures to ozone. The results show that the use of some products may result in potential health impacts.

  6. [Correlation Analysis Between Characteristics of VOCs and Ozone Formation Potential in Summer in Nanjing Urban District].

    PubMed

    Yang, Xiao-xiao; Tang, Li-li; Zhang, Yun-jiang; Mu, Ying-feng; Wang, Ming; Chen, Wen-tai; Zhou, Hong-cang; Hua, Yan; Jiang, Rong-xin

    2016-02-15

    Volatile organic compounds (VOCs) is an important precursor of photochemical ozone pollution (O3) in the atmosphere. Their concentration variation directly affects the characteristics of the ozone pollution. The concentration, speciation of VOCs, ozone and its precursors in Nanjing were analyzed and measured using online gas detection systems in August 2013. VOCs/NOx discriminant method was used to get the sensitive control factors of ozone. The results showed that the averaged volume fraction of VOCs was 52. 05 x 10(-9), and the largest one reached 200 x 10(-9) in Nanjing urban district. The order of volume fraction of each species VOCs was alkane > oxygen-containing VOCs > alkene > aromatics. The averaged concentration of ozone was 76.5 microg x m(-1) and the exceeding concentration of hourly standard was 5.9%. The change trends of ozone precursors VOCs and NOx were basically identical and Ozone showed the obvious negative correlation during the period of high concentrations of ozone. There were some differences in the concentrations of the same VOCs in different ozone concentration periods. The ozone generation in Nanjing urban district was sensitive to VOCs, and Nanjing belonged to VOCs control area in summer.

  7. 16 CFR 260.11 - Ozone-safe and ozone-friendly claims.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... friendly to, the ozone layer or the atmosphere. Example 1: A product is labeled “ozone-friendly.” The claim... 16 Commercial Practices 1 2013-01-01 2013-01-01 false Ozone-safe and ozone-friendly claims. 260.11... THE USE OF ENVIRONMENTAL MARKETING CLAIMS § 260.11 Ozone-safe and ozone-friendly claims. It...

  8. 16 CFR 260.11 - Ozone-safe and ozone-friendly claims.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... friendly to, the ozone layer or the atmosphere. Example 1: A product is labeled “ozone-friendly.” The claim... 16 Commercial Practices 1 2014-01-01 2014-01-01 false Ozone-safe and ozone-friendly claims. 260.11... THE USE OF ENVIRONMENTAL MARKETING CLAIMS § 260.11 Ozone-safe and ozone-friendly claims. It...

  9. Historical Analysis and Charaterization of Ground Level Ozone for Canada and United State

    NASA Astrophysics Data System (ADS)

    Lin, H.; Li, H.; Auld, H.

    2003-12-01

    Ground-level ozone has long been recognized as an important health and ecosystem-related air quality concern in Canada and the United States. In this work we seek to understand the characteristics of ground level ozone conditions for Canada and United States to support the Ozone Annex under the Canada-U.S. Air Quality Agreement. Our analyses are based upon the data collected by Canadian National Air Pollution Surveillance (NAPS, the NAPS database has also been expanded to include U.S. EPA ground level ozone data) network. Historical ozone data from 1974 to 2002 at a total of 538 stations (253 Canadian stations and 285 U.S. stations) were statistically analyzed using several methodologies including the Canada Wide Standard (CWS). A more detailed analysis including hourly, daily, monthly, seasonally and yearly ozone concentration distributions and trends was undertaken for 54 stations.

  10. Procedures for estimating the frequency of commercial airline flights encountering high cabin ozone levels

    NASA Technical Reports Server (NTRS)

    Holdeman, J. D.

    1979-01-01

    Three analytical problems in estimating the frequency at which commercial airline flights will encounter high cabin ozone levels are formulated and solved: namely, estimating flight-segment mean levels, estimating maximum-per-flight levels, and estimating the maximum average level over a specified flight interval. For each problem, solution procedures are given for different levels of input information - from complete cabin ozone data, which provides a direct solution, to limited ozone information, such as ambient ozone means and standard deviations, with which several assumptions are necessary to obtain the required estimates. Each procedure is illustrated by an example case calculation that uses simultaneous cabin and ambient ozone data obtained by the NASA Global Atmospheric Sampling Program. Critical assumptions are discussed and evaluated, and the several solutions for each problem are compared. Example calculations are also performed to illustrate how variations in lattitude, altitude, season, retention ratio, flight duration, and cabin ozone limits affect the estimated probabilities.

  11. Reagentless-continuous determination of aqueous ozone with glass tube separator-thin film semiconductor

    SciTech Connect

    Aoki, Toyoaki; Oguro, Hiroshi )

    1990-01-01

    A method without any reagent for the determination of ultra-trace aqueous ozone utilizing a glass tube-separation process and a thin film semiconductor is proposed. The glass tube was used as the separator to transfer ozone from water into a gas phase. Ozone was transferred into clean air flowing in the tube and then was continuously monitored at the thin film semiconductor. Signals were proportional to concentration of aqueous ozone more than 5 ppb. Detection limit (S/N=3) was 0.02 ppt for aqueous ozone. The relative standard deviation (n=7) was 3.8% at 7.6 ppb. The interference from hydrogen peroxide, monochloramine, and dichloramine were completely eliminated. The sensitivity of aqueous ozone was 45 times greater than that of hypochlorite.

  12. The effect of ozone associated with summertime photochemical smog on the frequency of asthma visits to hospital emergency departments

    SciTech Connect

    Cody, R.P. ); Weisel, C.P.; Lioy, P.J. Environmental and Occupational Health Sciences Institute, Piscataway, NJ ); Birnbaum, G. )

    1992-08-01

    A retrospective study using ambient ozone, temperature, and other environmental variables and their effect on the frequency of hospital visits for asthma was conducted in New Jersey, an area that often exceeds the allowable national standard for ozone. Data on emergency department visits for asthma, bronchitis, and finger wounds (a nonrespiratory control) were analyzed for the period May through August for 1988 and 1989. Asthma visits were correlated with temperature while the correlation between asthma visits and ozone concentration was nonsignificant. However, when temperature was controlled for in a multiple regression analysis, a highly significant relationship between asthma visits and ozone concentration was identified. Between 13 and 15% of the variability of the asthma visits and ozone concentration was identified. Between 13 and 15% of the variability of the asthma visits was explained in the regression model by temperature and ambient ozone levels. This association, when compared to similar studies in Canada, shows the contribution of ozone to asthma admissions to be stronger in areas with higher ozone concentrations. Thus, among regions with periodic accumulations of ozone in the ambient atmosphere, an exposure-response relationship may be discernible. This supports the need to attain air quality standards for ozone to protect individuals in the general population from the adverse health effects caused by ambient ozone exposure. 21 refs., 1 fig., 6 tabs.

  13. Precision ozone calibration system based on vapor pressures of ozone

    NASA Technical Reports Server (NTRS)

    Mauersberger, K.; Hanson, D.; Morton, J.

    1987-01-01

    A precision ozone calibration system for stratospheric research has been developed and evaluated. Vapor pressures above solid ozone are mixed with a carrier gas (N2) to produce stratospheric ozone mixing ratios at total pressures of 1 to cover 20 torr. The uncertainty in the ozone mixing ratios is approximately + or - 1.5 percent, the stability of ozone is + or - 0.3 percent. Experiments to be calibrated may sample the gas mixture over a wide range of flow rates; the maximum throughput of gas with corrections of less than 1 percent to ozone is about 200 torr 1/min. A mass spectrometer system continuously monitors the purity and stability of the N2-O3 gas mixture.

  14. Evaluation of ACCMIP Outgoing Longwave Radiation from Tropospheric Ozone Using TES Satellite Observations.

    NASA Technical Reports Server (NTRS)

    Bowman, Kevin W.; Shindell, Drew Todd; Worden, H. M.; Lamarque, J. F.; Young, P. J.; Stevenson, D. S.; Qu, Z.; delaTorre, M.; Bergmann, D.; Cameron-Smith, P. J.; Collins, W. J.; Doherty, R.; Dalsoren, S. B.; Faluvegi, G.; Folberth, G.; Horowitz, L. W.; Josse, B. M.; Lee, Y. H.; MacKenzie, I. A.; Myhre, G.; Nagashima, T.; Naik, V.; Strode, S. A.; Kulawik, S. S..; Worden, J. R.

    2013-01-01

    We use simultaneous observations of tropospheric ozone and outgoing longwave radiation (OLR) sensitivity to tropospheric ozone from the Tropospheric Emission Spectrometer (TES) to evaluate model tropospheric ozone and its effect on OLR simulated by a suite of chemistry-climate models that participated in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP). The ensemble mean of ACCMIP models show a persistent but modest tropospheric ozone low bias (5-20 ppb) in the Southern Hemisphere (SH) and modest high bias (5-10 ppb) in the Northern Hemisphere (NH) relative to TES ozone for 2005-2010. These ozone biases have a significant impact on the OLR. Using TES instantaneous radiative kernels (IRK), we show that the ACCMIP ensemble mean tropospheric ozone low bias leads up to 120mW/ sq. m OLR high bias locally but zonally compensating errors reduce the global OLR high bias to 39+/- 41mW/ sq. m relative to TES data. We show that there is a correlation (Sq. R = 0.59) between the magnitude of the ACCMIP OLR bias and the deviation of the ACCMIP preindustrial to present day (1750-2010) ozone radiative forcing (RF) from the ensemble ozone RF mean. However, this correlation is driven primarily by models whose absolute OLR bias from tropospheric ozone exceeds 100mW/ sq. m. Removing these models leads to a mean ozone radiative forcing of 394+/- 42mW/ sq. m. The mean is about the same and the standard deviation is about 30% lower than an ensemble ozone RF of 384 +/- 60mW/ sq. m derived from 14 of the 16 ACCMIP models reported in a companion ACCMIP study. These results point towards a profitable direction of combining satellite observations and chemistry-climate model simulations to reduce uncertainty in ozone radiative forcing.

  15. Response of macaque bronchiolar epithelium to ambient concentrations of ozone.

    PubMed Central

    Harkema, J. R.; Plopper, C. G.; Hyde, D. M.; St George, J. A.; Wilson, D. W.; Dungworth, D. L.

    1993-01-01

    Recently, we reported that exposure to ambient concentrations of ozone, near the U.S. National Ambient Air Quality Standard (0.12 ppm), induced significant nasal epithelial lesions in a non-human primate, the bonnet monkey. The present study defines the effects of ambient concentrations of ozone on the surface epithelium lining respiratory bronchioles and on the underlying bronchiolar interstitium in these same monkeys. Bonnet monkeys were exposed to filtered air or to 0.15 or 0.30 ppm ozone 8 hours/day for 6 or 90 days. At the end of exposures, monkeys were anesthetized and killed by exsanguination. Microdissected bronchiolar airways of infusion-fixed lungs were evaluated morphometrically by light microscopy and quantitatively by scanning and transmission electron microscopy for ozone-induced epithelial changes. Hyperplasia of nonciliated, cuboidal epithelial cells and intraluminal accumulation of macrophages characterized ozone-induced lesions in respiratory bronchioles. There were no significant differences in epithelial thickness or cell numbers among ozone-exposed groups. Ozone-exposed epithelium was composed of 80% cuboidal and 20% squamous cells compared with 40% cuboidal and 60% squamous cells in filtered air controls. In addition, the arithmetic mean thickness of the surface epithelium, a measure of tissue mass per unit area of basal lamina, was significantly increased in all of the ozone-exposed groups. The number of cuboidal epithelial cells per surface area of basal lamina was increased above control values by 780% after 6 days exposure to 0.15 ppm, 777% after 90 days to 0.15 ppm, and 996% after 90 days exposure to 0.30 ppm. There was also a significant ozone-induced increase in the thickness of the bronchiolar interstitium that was due to an increase in both cellular and acellular components. These results demonstrate that exposure to low ambient concentrations of ozone, near the current. National Ambient Air Quality Standard, induces pulmonary lesions

  16. Measurement of ozone production sensor

    NASA Astrophysics Data System (ADS)

    Cazorla Andrade, Maria Del Carmen

    The Measurement of Ozone Production Sensor (MOPS) is a new ambient air monitor that measures directly the rate of ozone production in the atmosphere. The sensor consists of two environmental chambers made of UV-transmitting Teflon film continuously exposed to the solar radiation, a unit to convert NO2 to O3, and a modified ozone monitor. In the sample chamber, photolysis processes and radical chemistry produce ozone just as it happens in the atmosphere. In the second chamber, called the reference chamber, a UV-blocking film prevents radical formation in a way that only the photostationary state component of ozone formation is retained. High-efficiency conversion of NO2 to O3 accounts for differences in the NOx photostationary state between both chambers. An ozone monitor operating without its ozone scrubber detects the ozone differential between the sample and the reference chamber. By doing so, the photostationary state component of ozone formation is canceled out and the ozone produced via radical chemistry is detected. The ozone differential is divided by the exposure time of the air in the chambers to find the rate of ozone production. Radical abundance measurements, wall loss tests and radiometric measurements demonstrate the feasibility of the technique. The MOPS was deployed in a rural environment, on the campus of Penn State University (September 2008), and in an urban environment, in Houston during the Study of Houston Atmospheric Radical Precursors SHARP (15 Apr to 31 May, 2009). The MOPS retrieved the first experimental plots of ambient P(O 3) vs. NO in both locations. In addition, the sensitivity of ozone production in these two environments was studied by adding NOx mixtures to the ambient air and looking at the response in the production of ozone. The results presented in this work demonstrate how an extended use of the MOPS can contribute to the improvement of air quality regulations by quantifying ozone production and ozone transport at a regional

  17. TOMS Ozone Anomalies and Ozone Retrieval Errors Over Cloudy Areas

    NASA Astrophysics Data System (ADS)

    Liu, X.; Newchurch, M.; Kim, J.; Bhartia, P. K.; Loughman, R.

    2003-12-01

    This study characterizes TOMS Ozone Retrieval Errors (OREs) associated with incorrect Cloud-Top Pressures (CTPs) and with assuming opaque Lambertian clouds, investigates these errors' effects on tropospheric ozone derivation, and analyzes ozone anomalies over TOMS data. Large errors occurring in TOMS assumed CTPs and inaccurate CTP-caused OREs are most significantly from inappropriately added ozone below clouds. Because OREs are usually within the TOMS retrieval precision when Cloud Optical Depth (COD)>20, assuming Lambertian surface is good. Because of In-Cloud Ozone Absorption ENhancement (ICOAEN), assuming opaque clouds can introduce large positive OREs even for optically thick clouds. For a 2-12 km water cloud of COD 40 with 20.8 DU ozone inside the cloud, the ORE is 17.8 DU at nadir. The ICOAEN effect depends strongly on viewing geometry and inter-cloud ozone amount and distribution; it is typically 5-13 DU over the tropical Atlantic and Africa and 1-7 DU over the tropical Pacific for deep convective clouds. The negative errors from using the TOMS Partial Cloud Model (PCM) partly cancel other positive errors. At COD < 5, the TOMS algorithm retrieves approximately the correct total ozone because of compensating errors. With increasing COD up to 20-40, negative PCM effect decreases to almost zero, and the overall positive ORE increases and is dominated by ICOAEN effect. The ICOAEN effect can largely underestimate tropospheric ozone derived from cloudy/clear difference techniques. The convective cloud differential and cloud-clear pair methods use minimum ozone above clouds to cancel positive errors. A Positive or Negative Ozone Anomaly (POA/NOA) is defined to occur if the ozone/reflectivity correlation coefficient in a region is >0.5 or <-0.5. Average fractions of OA occurrence are 31.8% and 35.8% in Nimbus-7 and Earth-Probe TOMS data, respectively. Most tropical NOAs result from large cloud-height errors; corrections lead to 50-70% POAs in the tropics because of

  18. Ozonated olive oils and the troubles

    PubMed Central

    Uysal, Bulent

    2014-01-01

    One of the commonly used methods for ozone therapy is ozonated oils. Most prominent type of used oils is extra virgin olive oil. But still, each type of unsaturated oils may be used for ozonation. There are a lot of wrong knowledge on the internet about ozonated oils and its use as well. Just like other ozone therapy studies, also the studies about ozone oils are inadequate to avoid incorrect knowledge. Current data about ozone oil and its benefits are produced by supplier who oversees financial interests and make misinformation. Despite the rapidly increasing ozone oil sales through the internet, its quality and efficacy is still controversial. Dozens of companies and web sites may be easily found to buy ozonated oil. But, very few of these products are reliable, and contain sufficiently ozonated oil. This article aimed to introduce the troubles about ozonated oils and so to inform ozonated oil users. PMID:26401346

  19. Effect of ozone on respiratory responses in subjects with asthma.

    PubMed Central

    Koenig, J Q

    1995-01-01

    In the process of understanding the respiratory effects of individual air pollutants, it is useful to consider which populations seem to be most susceptible to the exposures. Ozone is the most ubiquitous air pollutant in the United States, and there is great interest in the extent of susceptibility to this air pollutant. This review presents evidence that individuals with asthma are more susceptible to adverse respiratory effects from ozone exposure than are nonasthmatic individuals under similar circumstances. In studies comparing patients with asthma to nonasthmatic subjects, research has shown increased pulmonary-function decrements, an increased frequency of bronchial hyperresponsiveness in ozone responders, increased signs of upper airway inflammation after ozone exposure, and an increased response to inhaled sulfur dioxide or allergen in the subjects with asthma. Subjects with asthma are indeed a population susceptible to the inhaled effects of ozone. These data need to be considered by regulators who are charged with setting air quality standards to protect even the most susceptible members of the population. They also underline the importance of strategies to reduce human exposure to ambient ozone. PMID:7614933

  20. Effect of ozone on respiratory responses in subjects with asthma

    SciTech Connect

    Koenig, J.Q.

    1995-03-01

    In the process of understanding the respiratory effects of individual air pollutants, it is useful to consider which populations seem to be most susceptible to the exposures. Ozone is the most ubiquitous air pollutant in the United States, and there is great interest in the extent of susceptibility to this air pollutant. This review presents evidence that individuals with asthma are more susceptible to adverse respiratory effects from ozone exposure than are nonasthmatic individuals under similar circumstances. In studies comparing patients with asthma to nonasthmatic subjects, research has shown increased pulmonary-function decrements, an increased frequency of bronchial hyperresponsiveness in ozone responders, increased signs of upper airway inflammation after ozone exposure, and an increased response to inhaled sulfur dioxide or allergen in the subjects with asthma. Subjects with asthma are indeed a population susceptible to the inhaled effects of ozone. These data need to be considered by regulators who are charged with setting air quality standards to protect even the most susceptible members of the population. They also underline the importance of strategies to reduce human exposure to ambient ozone. 16 refs., 1 fig.

  1. Ozone therapy as an adjuvant for endondontic protocols: microbiological – ex vivo study and citotoxicity analyses

    PubMed Central

    NOGALES, Carlos Goes; FERREIRA, Marina Beloti; MONTEMOR, Antonio Fernando; RODRIGUES, Maria Filomena de Andrade; Lage-MARQUES, José Luiz; ANTONIAZZI, João Humberto

    2016-01-01

    ABSTRACT Objectives This study evaluated the antimicrobial efficacy of ozone therapy in teeth contaminated with Pseudomonas aeruginosa, Enterococcus faecalis, and Staphylococcus aureus using a mono-species biofilm model. Parallel to this, the study aimed to evaluate the cytotoxicity of ozone for human gingival fibroblasts. Material and Methods: One hundred and eighty single-root teeth were contaminated with a mono-species biofilm of Enterococcus faecalis, Pseudomonas aeruginosa, and Staphylococcus aureus. Groups were formed: Group I – control; Group II – standard protocol; Group III – standard protocol + ozone gas at 40 µg/mL; and Group IV – standard protocol + aqueous ozone at 8 µg/mL. In parallel, human gingival fibroblasts were submitted to the MTT test. Cells were plated, then ozone was applied as follows: Group I (control) – broth medium; Group II – aqueous ozone at 2 µg/mL; Group III – aqueous ozone at 5 µg/mL; and Group IV – aqueous ozone at 8 µg/mL. Data were submitted to the Kruskal Wallis test and Bonferroni post hoc analyses to assess microbiology and cytotoxicity, respectively (p<0.05%). Results The results revealed antimicrobial efficacy by Group IV with no CFU count. The cytotoxicity assay showed Groups III and IV to be the most aggressive, providing a decrease in cell viability at hour 0 from 100% to 77.3% and 68.6%, respectively. Such a decrease in cell viability was reverted, and after 72 hours Groups III and IV provided the greatest increase in cell viability, being statistically different from Groups I and II. Conclusion According to the applied methodology and the limitations of this study, it was possible to conclude that ozone therapy improved the decontamination of the root canal ex vivo. Ozone was toxic to the cells on first contact, but cell viability was recovered. Thus, these findings suggest that ozone might be useful to improve root canal results. PMID:28076466

  2. Determination of aqueous ozone for potable water treatment applications by chemiluminescence flow-injection analysis. A feasibility study.

    PubMed

    Chung, H K; Bellamy, H S; Dasgupta, P K

    1992-06-01

    The feasibility of determining aqueous ozone by chemiluminescence flow-injection analysis (CL-FIA) was studied for applications in potable water treatment. The ozonated water sample is injected into a pure water carrier and mixed with a dye reagent in front of a photodetector. Many reagents undergo fast CL reactions with aqueous ozone. Most of these reactions display considerable selectivity for ozone over other oxidants of importance in water treatment. Even when there is steady-state response to another oxidant, significant discrimination against the interferents is possible by taking advantage of the much faster kinetics of the CL reaction with ozone. A simple design of a Siemens-type ozone generator and preparation of standard ozone solutions are also described.

  3. Secular variations of tropospheric ozone

    NASA Astrophysics Data System (ADS)

    Khrgian, A. Kh.

    1988-02-01

    The dependence of secular variations of tropospheric ozone on decreases of temperature and cloud growth in Central Europe is assessed on the basis of Vienna, Paris, and Athens data for 1853-1920. Decreases in ozone content occurring with a certain time lag after major volcanic eruptions (e.g., Krakatoa) are examined. The effect of the Tungusk-meteorite fall on ozone content is also discussed.

  4. Mars ozone: Mariner 9 revisited

    NASA Technical Reports Server (NTRS)

    Lindner, Bernhard Lee

    1995-01-01

    The efficacy of the UV reflectance spectroscopy technique used by Mariner 9 to remotely measure ozone abundance at Mars is discussed. Due to temporal and spatial variability in cloud and dust amount, previously inferred ozone abundances could be underestimated by a factor of 3. Until the large uncertainty in cloud and dust scattering properties and opacities can be reduced, the ozone abundance inferred by the reflectance spectroscopy technique will always have significant uncertainty.

  5. Protecting beans from ozone

    SciTech Connect

    Pierce, R.

    1983-03-01

    A chemical treatment to protect navy beans from ozone damage increased yields by an average of more than 20% in 3 years of tests. An experimental antioxidant chemical, EDU, made by the DuPont company was tested as soil applications and sprays on several varieties and under a variety of soil and planting conditions. The average yield increases were between 16 and 24%. Chemical treatment also increased snap bean pod production by 12%.

  6. Protecting the ozone layer.

    PubMed

    Munasinghe, M; King, K

    1992-06-01

    Stratospheric ozone layer depletion has been recognized as a problem by the Vienna Convention for the Protection of the Ozone Layer and the 1987 Montreal Protocol (MP). The ozone layer shields the earth from harmful ultraviolet radiation (UV-B), which is more pronounced at the poles and around the equator. Industrialized countries have contributed significantly to the problem by releasing chlorofluorocarbons (CFCs) and halons into the atmosphere. The effect of these chemicals, which were known for their inertness, nonflammability, and nontoxicity, was discovered in 1874. Action to deal with the effects of CFCs and halons was initiated in 1985 in a 49-nation UN meeting. 21 nations signed a protocol limiting ozone depleting substances (ODS): CFCs and halons. Schedules were set based on each country's use in 1986; the target phaseout was set for the year 2000. The MP restricts trade in ODSs and weights the impact of substances to reflect the extent of damage; i.e., halons are 10 times more damaging than CFCs. ODS requirements for developing countries were eased to accommodate scarce resources and the small fraction of ODS emissions. An Interim Multilateral Fund under the Montreal Protocol (IMFMP) was established to provide loans to finance the costs to developing countries in meeting global environmental requirements. The IMFMP is administered by the World Bank, the UN Environmental Program, and the UN Development Program. Financing is available to eligible countries who use .3 kg of ODS/person/year. Rapid phaseout in developed countries has occurred due to strong support from industry and a lower than expected cost. Although there are clear advantages to rapid phaseout, there were no incentives included in the MP for rapid phaseout. Some of the difficulties occur because the schedules set minimum targets at the lowest possible cost. Also, costs cannot be minimized by a country-specific and ODS-specific process. The ways to improve implementation in scheduling and

  7. Ozone measurement systems improvements studies

    NASA Technical Reports Server (NTRS)

    Thomas, R. W.; Guard, K.; Holland, A. C.; Spurling, J. F.

    1974-01-01

    Results are summarized of an initial study of techniques for measuring atmospheric ozone, carried out as the first phase of a program to improve ozone measurement techniques. The study concentrated on two measurement systems, the electro chemical cell (ECC) ozonesonde and the Dobson ozone spectrophotometer, and consisted of two tasks. The first task consisted of error modeling and system error analysis of the two measurement systems. Under the second task a Monte-Carlo model of the Dobson ozone measurement technique was developed and programmed for computer operation.

  8. Regulatory ozone modeling: status, directions, and research needs.

    PubMed Central

    Georgopoulos, P G

    1995-01-01

    The Clean Air Act Amendments (CAAA) of 1990 have established selected comprehensive, three-dimensional, Photochemical Air Quality Simulation Models (PAQSMs) as the required regulatory tools for analyzing the urban and regional problem of high ambient ozone levels across the United States. These models are currently applied to study and establish strategies for meeting the National Ambient Air Quality Standard (NAAQS) for ozone in nonattainment areas; State Implementation Plans (SIPs) resulting from these efforts must be submitted to the U.S. Environmental Protection Agency (U.S. EPA) in November 1994. The following presentation provides an overview and discussion of the regulatory ozone modeling process and its implications. First, the PAQSM-based ozone attainment demonstration process is summarized in the framework of the 1994 SIPs. Then, following a brief overview of the representation of physical and chemical processes in PAQSMs, the essential attributes of standard modeling systems currently in regulatory use are presented in a nonmathematical, self-contained format, intended to provide a basic understanding of both model capabilities and limitations. The types of air quality, emission, and meteorological data needed for applying and evaluating PAQSMs are discussed, as well as the sources, availability, and limitations of existing databases. The issue of evaluating a model's performance in order to accept it as a tool for policy making is discussed, and various methodologies for implementing this objective are summarized. Selected interim results from diagnostic analyses, which are performed as a component of the regulatory ozone modeling process for the Philadelphia-New Jersey region, are also presented to provide some specific examples related to the general issues discussed in this work. Finally, research needs related to a) the evaluation and refinement of regulatory ozone modeling, b) the characterization of uncertainty in photochemical modeling, and c

  9. The impact of climate change on ozone-related mortality in Sydney.

    PubMed

    Physick, William; Cope, Martin; Lee, Sunhee

    2014-01-13

    Coupled global, regional and chemical transport models are now being used with relative-risk functions to determine the impact of climate change on human health. Studies have been carried out for global and regional scales, and in our paper we examine the impact of climate change on ozone-related mortality at the local scale across an urban metropolis (Sydney, Australia). Using three coupled models, with a grid spacing of 3 km for the chemical transport model (CTM), and a mortality relative risk function of 1.0006 per 1 ppb increase in daily maximum 1-hour ozone concentration, we evaluated the change in ozone concentrations and mortality between decades 1996-2005 and 2051-2060. The global model was run with the A2 emissions scenario. As there is currently uncertainty regarding a threshold concentration below which ozone does not impact on mortality, we calculated mortality estimates for the three daily maximum 1-hr ozone concentration thresholds of 0, 25 and 40 ppb. The mortality increase for 2051-2060 ranges from 2.3% for a 0 ppb threshold to 27.3% for a 40 ppb threshold, although the numerical increases differ little. Our modeling approach is able to identify the variation in ozone-related mortality changes at a suburban scale, estimating that climate change could lead to an additional 55 to 65 deaths across Sydney in the decade 2051-2060. Interestingly, the largest increases do not correspond spatially to the largest ozone increases or the densest population centres. The distribution pattern of changes does not seem to vary with threshold value, while the magnitude only varies slightly.

  10. Air Emissions Inventory Guidance for Implementation of Ozone and Particulate Matter NAAQS and Regional Haze Regulations

    EPA Pesticide Factsheets

    Guidance document on how to develop emission inventories to meet State Implementation Plan requirements for complying with the 8-hour ozone national ambient air quality standards (NAAQS), the revised particulate matter (PM) NAAQS, and the regional haze reg

  11. Air Quality Modeling Technical Support Document for the 2015 Ozone NAAQS Preliminary Interstate Transport Assessment

    EPA Pesticide Factsheets

    In this technical support document (TSD) EPA describes the air quality modeling performed to support the 2015 ozone National Ambient Air Quality Standards (NAAQS) preliminary interstate transport assessment Notice of Data Availability (NODA).

  12. Calibration of the Ogawa passive ozone sampler for aircraft cabins

    NASA Astrophysics Data System (ADS)

    Bhangar, Seema; Singer, Brett C.; Nazaroff, William W.

    2013-02-01

    Elevated ozone levels in aircraft cabins would pose a health hazard to exposed passengers and crew. The Ogawa passive sampler is a potentially useful tool for measuring in-cabin ozone levels. Accurate interpretation of measured values requires knowing the effective collection rate of the sampler. To calibrate the passive sampler for the aircraft-cabin environment, ozone was measured simultaneously with an Ogawa sampler and an active ozone analyzer that served as a transfer standard, on 11 commercial passenger flights, during Feb-Apr 2007. An empirical pressure-independent effective collection rate that can be used to convert nitrate mass to ozone mixing ratio was determined to be 14.3 ± 0.9 atm cm3 min-1 (mean ± standard error). This value is similar to estimates from other applications where airflow rates are low, such as in personal monitoring and in chamber studies. This study represents the first field calibration of any passive sampler for the aircraft cabin environment.

  13. Common Calibration Source for Monitoring Long-term Ozone Trends

    NASA Technical Reports Server (NTRS)

    Kowalewski, Matthew

    2004-01-01

    Accurate long-term satellite measurements are crucial for monitoring the recovery of the ozone layer. The slow pace of the recovery and limited lifetimes of satellite monitoring instruments demands that datasets from multiple observation systems be combined to provide the long-term accuracy needed. A fundamental component of accurately monitoring long-term trends is the calibration of these various instruments. NASA s Radiometric Calibration and Development Facility at the Goddard Space Flight Center has provided resources to minimize calibration biases between multiple instruments through the use of a common calibration source and standardized procedures traceable to national standards. The Facility s 50 cm barium sulfate integrating sphere has been used as a common calibration source for both US and international satellite instruments, including the Total Ozone Mapping Spectrometer (TOMS), Solar Backscatter Ultraviolet 2 (SBUV/2) instruments, Shuttle SBUV (SSBUV), Ozone Mapping Instrument (OMI), Global Ozone Monitoring Experiment (GOME) (ESA), Scanning Imaging SpectroMeter for Atmospheric ChartographY (SCIAMACHY) (ESA), and others. We will discuss the advantages of using a common calibration source and its effects on long-term ozone data sets. In addition, sphere calibration results from various instruments will be presented to demonstrate the accuracy of the long-term characterization of the source itself.

  14. Ultraviolet Radiation and Stratospheric Ozone

    NASA Technical Reports Server (NTRS)

    Stolarski, R.

    2003-01-01

    Ultraviolet radiation from the sun produces ozone in the stratosphere and it participates in the destruction of ozone. Absorption of solar ultraviolet radiation by ozone is the primary heating mechanism leading to the maximum in temperature at the stratopause. Variations of solar ultraviolet radiation on both the 27-day solar rotation period and the 11-year solar cycle affect ozone by several mechanisms. The temperature and ozone in the upper stratosphere respond to solar uv variations as a coupled system. An increase in uv leads to an increase in the production of ozone through the photolysis of molecular oxygen. An increase in uv leads to an increase in temperature through the heating by ozone photolysis. The increase in temperature leads to a partially-offsetting decrease in ozone through temperature-dependent reaction rate coefficients. The ozone variation modulates the heating by ozone photolysis. The increase in ozone at solar maximum enhances the uv heating. The processes are understood and supported by long-term data sets. Variation in the upper stratospheric temperatures will lead to a change in the behavior of waves propagating upward from the troposphere. Changes in the pattern of wave dissipation will lead to acceleration or deceleration of the mean flow and changes in the residual or transport circulation. This mechanism could lead to the propagation of the solar cycle uv variation from the upper stratosphere downward to the lower stratosphere. This process is not well-understood and has been the subject of an increasing number of model studies. I will review the data analyses for solar cycle and their comparison to model results.

  15. Use of an indoor air quality model (IAQM) to estimate indoor ozone levels.

    PubMed

    Hayes, S R

    1991-02-01

    Currently, outdoor ozone levels in many U.S. cities exceed the primary health-based national ambient air quality standard. While outdoor ozone levels are an important measure of the severity of those exceedances, people typically spend more than 80 percent of their time indoors, where ozone levels are lower. Indoor ozone levels range from 10 to 80 percent of outdoor levels, with many people receiving a substantial portion of their ozone exposure while indoors. This paper uses an indoor air quality model (IAQM) to estimate indoor ozone levels by microenvironment type (home, office, and vehicle) and configuration (windows open, windows closed, older construction, weatherized, and air conditioned). The formulation of IAQM is discussed, along with specification of model parameters for ozone. The multicompartment version of IAQM is described, with a single-compartment version used for the analyses. IAQM-calculated ozone indoor-outdoor ratios compare well with research-reported values. Results indicate that ozone peak-concentration indoor-outdoor ratios range as follows: home--0.65 (windows open), 0.36 (air conditioned), 0.23 (typical construction, windows closed), and 0.05 (energy-efficient construction, windows closed); office--0.82 (heating, ventilation and air conditioning systems supplying 100 percent outdoor air), 0.60 (typical HVAC), and 0.32 (energy-efficient HVAC); and vehicle--0.41 (85 mph), 0.33 (55 mph), and 0.21 (10 mph). Analysis results are presented to characterize IAQM's sensitivity to assumed model parameters.

  16. Spatial distribution of tropospheric ozone in national parks of California: interpretation of passive-sampler data.

    PubMed

    Ray, J D

    2001-09-28

    The National Park Service (NPS) has tested and used passive ozone samplers for several years to get baseline values for parks and to determine the spatial variability within parks. Experience has shown that the Ogawa passive samplers can provide +/-10% accuracy when used with a quality assurance program consisting of blanks, duplicates, collocated instrumentation, and a standard operating procedure that carefully guides site operators. Although the passive device does not meet EPA criteria as a certified method (mainly, that hourly values be measured), it does provide seasonal summed values of ozone. The seasonal ozone concentrations from the passive devices can be compared to other monitoring to determine baseline values, trends, and spatial variations. This point is illustrated with some kriged interpolation maps of ozone statistics. Passive ozone samplers were used to get elevational gradients and spatial distributions of ozone within a park. This was done in varying degrees at Mount Rainier, Olympic, Sequoia-Kings Canyon, Yosemite, Joshua Tree, Rocky Mountain, and Great Smoky Mountains national parks. The ozone has been found to vary by factors of 2 and 3 within a park when average ozone is compared between locations. Specific examples of the spatial distributions of ozone in three parks within California are given using interpolation maps. Positive aspects and limitations of the passive sampling approach are presented.

  17. Ozone profile measurements at McMurdo Station Antarctica during the spring of 1987

    NASA Technical Reports Server (NTRS)

    Hofmann, D. J.; Harder, J. W.; Rosen, J. M.; Hereford, J.; Carpenter, J. R.

    1988-01-01

    During the Antarctic spring of 1986, 33 ozone soundings were conducted from McMurdo Station. These data indicated that the springtime decrease in ozone occurred rapidly between the altitudes of 12 and 20 km. During 1987, these measurements were repeated with 50 soundings between 29 August and 9 November. Digital conversions of standard electrochemical cell ozonesondes were again employed. The ozonesonde pumps were individually calibrated for flow rate as the high altitude performance of these pumps have been in question. While these uncertainties are not large in the region of the ozone hole, they are significant at high altitude and apparently resulted in an underestimate of total ozone of about 7 percent (average) as compared to the Total Ozone Mapping Spectrometer (TOMS) in 1986, when the flow rate recommended by the manufacturer was used. At the upper altitudes (approx. 30 km) the flow rate may be overestimated by as much as 15 percent using recommended values (see Harder et al., The UW Digital Ozonesonde: Characteristics and Flow Rate Calibration, poster paper, this workshop). These upper level values are used in the extrapolation, at constant mixing ratio, required to complete the sounding for total ozone. The first sounding was on 29 August, prior to major ozone depletion, when 274 DU total ozone (25 DU extrapolated) was observed. By early October total ozone had decreased to the 150 DU range; it then increased during mid-October owing to motion of the vortex and returned to a value of 148 DU (29 DU extrapolated) on 27 October.

  18. Effects of model chemistry and data biases on stratospheric ozone assimilation

    NASA Astrophysics Data System (ADS)

    Coy, L.; Allen, D. R.; Eckermann, S. D.; McCormack, J. P.; Stajner, I.; Hogan, T. F.

    2007-06-01

    The innovations or observation minus forecast (O-F) residuals produced by a data assimilation system provide a convenient metric of evaluating global analyses. In this study, O-F statistics from the Global Ozone Assimilation Testing System (GOATS) are used to examine how ozone assimilation products and their associated O-F statistics depend on input data biases and ozone photochemistry parameterizations (OPP). All the GOATS results shown are based on a 6-h forecast and analysis cycle using observations from SBUV/2 (Solar Backscatter UltraViolet instrument-2) during September-October 2002. Results show that zonal mean ozone analyses are more independent of observation biases and drifts when using an OPP, while the mean ozone O-Fs are more sensitive to observation drifts when using an OPP. In addition, SD O-Fs (standard deviations) are reduced in the upper stratosphere when using an OPP due to a reduction of forecast model noise and to increased covariance between the forecast model and the observations. Experiments that changed the OPP reference state to match the observations by using an "adaptive" OPP scheme reduced the mean ozone O-Fs at the expense of zonal mean ozone analyses being more susceptible to data biases and drifts. Additional experiments showed that the upper boundary of the ozone DAS can affect the quality of the ozone analysis and therefore should be placed well above (at least a scale height) the region of interest.

  19. Effects of model chemistry and data biases on stratospheric ozone assimilation

    NASA Astrophysics Data System (ADS)

    Coy, L.; Allen, D. R.; Eckermann, S. D.; McCormack, J. P.; Stajner, I.; Hogan, T. F.

    2007-01-01

    The innovations or observation minus forecast (O-F) residuals produced by a data assimilation system provide a convenient metric of evaluating global analyses. In this study, O-F statistics from the Global Ozone Assimilation Testing System (GOATS) are used to examine how ozone assimilation products and their associated O-F statistics depend on input data biases and ozone photochemistry parameterizations (OPP). All the GOATS results shown are based on a 6-h forecast and analysis cycle using observations from SBUV/2 (Solar Backscatter UltraViolet instrument-2) during September-October 2002. Results show that zonal mean ozone analyses are more independent of observation biases and drifts when using an OPP, while the mean ozone O-Fs are more sensitive to observation drifts when using an OPP. In addition, SD O-Fs (standard deviations) are reduced in the upper stratosphere when using an OPP due to a reduction of forecast model noise and to increased covariance between the forecast model and the observations. Experiments that changed the OPP reference state to match the observations by using an "adaptive" OPP scheme reduced the mean ozone O-Fs at the expense of zonal mean ozone analyses being more susceptible to data biases and drifts. Additional experiments showed that the upper boundary of the ozone DAS can affect the quality of the ozone analysis and therefore should be placed well above (at least a scale height) the region of interest.

  20. Validation of OMI Total Ozone Retrievals from the SAO Ozone Profile Algorithm and Three Operational Algorithms 3 with Brewer Measurements

    NASA Astrophysics Data System (ADS)

    Bak, Juseon; Kim, Jae H.; Liu, Xiong; Chance, Kelly

    2015-04-01

    The optimal estimation (OE) based ozone profile algorithm developed at Smithsonian 3 Astrophysical Observatory (SAO) is assessed as to its accuracy to extract total ozone amount from 4 Ozone Monitoring Instrument (OMI) measurements through the validation using Brewer ground 5 based measurements between January 2005 and December 2008. We compare it against the quality of 6 three OMI operational ozone products, derived from NASA TOMS, KNMI DOAS, and KNMI OE 7 algorithms, respectively. The validation demonstrates that the SAO ozone profile algorithm generally 8 has the best total ozone retrieval performance compared to the three OMI operational ozone products. 9 The individual station comparisons show an agreement between SAO and Brewer within ± 1% except 10 at polar stations (~ -2 %), with a high correlation coefficient of ~ 0.99 at most stations. The KNMI OE 11 algorithm systematically overestimates the true total ozone value at all stations with a bias from 2 % 12 at low/mid latitude stations to 5 % at high latitude stations. On the other hand, TOMS/DOAS 13 algorithm underestimates total ozone by ~ -1.7 % on average. The standard deviations of differences 14 are ~ 1.8 % for SAO and TOMS while DOAS and KNMI show the standard deviation values of 2.2 15 and 2.5 %, respectively. The remarkable stability of SAO OE algorithm is found with no significant 16 dependency on algorithmic variables such as viewing geometries, cloud parameters, and time. In 17 comparison, the severe dependency on both solar and viewing zenith angles is found in KNMI OE 18 algorithm, which is characterized with a negative (positive) correlation with smaller (larger) solar 19 zenith angles and the strong cross-track dependent biases ranging from 4% at nadir and 1% at off-20 nadir positions. The dependence of DOAS and TOMS algorithms on the algorithmic variables is 21 marginal compared to KNMI OE algorithm, but distinct compared to SAO OE algorithm. Relative 22 differences between SAO/DOAS and

  1. Effects of ambient ozone on first-year growth and physiology of black cherry (Prunus serotina Ehrh. ) seedlings

    SciTech Connect

    Kolb, T.E.; Skelly, J.M.; Steiner, K.C.; Dunn, K. Pennsylvania State Univ., University Park )

    1993-06-01

    Black cherry seedlings of two open-pollinated families were exposed to ambient ozone in open plots (100%) and plots receiving non-filtered (95%), half-filtered (60%) and full-filtered (40%) concentrations via open-top chambers between early June and late-September 1992 in a replicated field experiment in central Pennsylvania. Seasonal 24-hour ambient ozone concentration averaged 34 ppb with a peak 1-hour concentration of 110 ppb. Foliar symptoms of ozone damage (adaxial stipple) occurred most prominently in open and non-filtered plots and differed between families. Net photosynthetic rate for both families was significantly lower in open and non-filtered plots compared with half- and full-filtered plots on most dates, while ozone concentration had no consistent effect on leaf conductance or dark respiration. Leaf conductance of the ozone sensitive family was significantly greater than the ozone tolerant family on most dates. First-year height and diameter growth were significantly lower in open and non-filtered plots compared with half- and full-filtered plots for both families.

  2. Unequivocal detection of ozone recovery in the Antarctic Ozone Hole through significant increases in atmospheric layers with minimum ozone

    NASA Astrophysics Data System (ADS)

    de Laat, Jos; van Weele, Michiel; van der A, Ronald

    2015-04-01

    An important new landmark in present day ozone research is presented through MLS satellite observations of significant ozone increases during the ozone hole season that are attributed unequivocally to declining ozone depleting substances. For many decades the Antarctic ozone hole has been the prime example of both the detrimental effects of human activities on our environment as well as how to construct effective and successful environmental policies. Nowadays atmospheric concentrations of ozone depleting substances are on the decline and first signs of recovery of stratospheric ozone and ozone in the Antarctic ozone hole have been observed. The claimed detection of significant recovery, however, is still subject of debate. In this talk we will discuss first current uncertainties in the assessment of ozone recovery in the Antarctic ozone hole by using multi-variate regression methods, and, secondly present an alternative approach to identify ozone hole recovery unequivocally. Even though multi-variate regression methods help to reduce uncertainties in estimates of ozone recovery, great care has to be taken in their application due to the existence of uncertainties and degrees of freedom in the choice of independent variables. We show that taking all uncertainties into account in the regressions the formal recovery of ozone in the Antarctic ozone hole cannot be established yet, though is likely before the end of the decade (before 2020). Rather than focusing on time and area averages of total ozone columns or ozone profiles, we argue that the time evolution of the probability distribution of vertically resolved ozone in the Antarctic ozone hole contains a better fingerprint for the detection of ozone recovery in the Antarctic ozone hole. The advantages of this method over more tradition methods of trend analyses based on spatio-temporal average ozone are discussed. The 10-year record of MLS satellite measurements of ozone in the Antarctic ozone hole shows a

  3. Health Benefits from Large-Scale Ozone Reduction in the United States

    PubMed Central

    Berman, Jesse D.; Fann, Neal; Hollingsworth, John W.; Pinkerton, Kent E.; Rom, William N.; Szema, Anthony M.; Breysse, Patrick N.; White, Ronald H.

    2012-01-01

    Background: Exposure to ozone has been associated with adverse health effects, including premature mortality and cardiopulmonary and respiratory morbidity. In 2008, the U.S. Environmental Protection Agency (EPA) lowered the primary (health-based) National Ambient Air Quality Standard (NAAQS) for ozone to 75 ppb, expressed as the fourth-highest daily maximum 8-hr average over a 24-hr period. Based on recent monitoring data, U.S. ozone levels still exceed this standard in numerous locations, resulting in avoidable adverse health consequences. Objectives: We sought to quantify the potential human health benefits from achieving the current primary NAAQS standard of 75 ppb and two alternative standard levels, 70 and 60 ppb, which represent the range recommended by the U.S. EPA Clean Air Scientific Advisory Committee (CASAC). Methods: We applied health impact assessment methodology to estimate numbers of deaths and other adverse health outcomes that would have been avoided during 2005, 2006, and 2007 if the current (or lower) NAAQS ozone standards had been met. Estimated reductions in ozone concentrations were interpolated according to geographic area and year, and concentration–response functions were obtained or derived from the epidemiological literature. Results: We estimated that annual numbers of avoided ozone-related premature deaths would have ranged from 1,410 to 2,480 at 75 ppb to 2,450 to 4,130 at 70 ppb, and 5,210 to 7,990 at 60 ppb. Acute respiratory symptoms would have been reduced by 3 million cases and school-loss days by 1 million cases annually if the current 75-ppb standard had been attained. Substantially greater health benefits would have resulted if the CASAC-recommended range of standards (70–60 ppb) had been met. Conclusions: Attaining a more stringent primary ozone standard would significantly reduce ozone-related premature mortality and morbidity. PMID:22809899

  4. A survey of ozone concentrations in rural western Utah: unexpected results and spatial heterogeneity from 2010-2013

    NASA Astrophysics Data System (ADS)

    Arens, S. J.; Harper, K.

    2013-12-01

    Ozone concentrations and meteorological variables were monitored at eleven sites in rural western Utah during late spring through summer of 2010-2013 to determine regional background concentrations of ozone and to determine attainment or nonattainment of the ozone National Ambient Air Quality Standard (NAAQS). Ozone concentrations have been monitored along the Wasatch Front of Utah (Logan, Ogden, Salt Lake City and Provo) for 30 years by the Utah Division of Air Quality (DAQ), but no ozone data from outside the cities of Wasatch Front existed prior to 2010. All rural sites, except Badger Springs, west of St. George, UT, were in attainment of the ozone NAAQS, which is 75 ppb averaged over 8 hours. However, ozone concentrations were higher than expected at seven of the eleven sites. All eleven sites were located in either small rural towns or uninhabited areas of western Utah, which were distant from anthropogenic emissions of ozone precursors. In 2010, ozone concentrations were relatively low along the Wasatch Front of Utah. Ozone concentrations exceeded 65 ppb for one day at three of four rural sites. Ozone concentrations at two of the four sites were generally in the range of expected rural ozone concentrations of 50-60 ppb. Ozone concentrations during 2011-2012 were higher throughout Utah compared to 2010. In 2011, 8-hour ozone concentrations exceeded 70 ppb for at least one day at four of five sites. The maximum 8-hour ozone concentration was 78 ppb, observed at Lytle Ranch, west of St. George, UT. Ozone concentrations at only one rural Utah site were in the expected range of 50-60 ppb. Ozone concentrations during 2012 were the highest observed during the four years of the study with 8-hour ozone concentrations exceeding 75 ppb at three of five rural sites and exceeding 70 ppb for at least four days at four of five sites. Although data collected was not considered regulatory by the EPA, the ozone NAAQS was exceeded at Badger Springs in southwestern Utah. Ozone

  5. EPA Proposes to Move DFW Area into Severe Ozone Category

    EPA Pesticide Factsheets

    DALLAS - (Feb. 10, 2015) The U.S. Environmental Protection Agency (EPA) proposed to reclassify the Dallas-Fort Worth area (DFW) as being in severe nonattainment of the original 8-hour ozone standard of 84 parts per billion. The proposal will be publ

  6. Establishing policy relevant background (PRB) ozone concentrations in the United States.

    PubMed

    McDonald-Buller, Elena C; Allen, David T; Brown, Nancy; Jacob, Daniel J; Jaffe, Daniel; Kolb, Charles E; Lefohn, Allen S; Oltmans, Samuel; Parrish, David D; Yarwood, Greg; Zhang, Lin

    2011-11-15

    Policy Relevant Background (PRB) ozone concentrations are defined by the United States (U.S.) Environmental Protection Agency (EPA) as those concentrations that would occur in the U.S. in the absence of anthropogenic emissions in continental North America (i.e., the U.S, Canada, and Mexico). Estimates of PRB ozone have had an important role historically in the EPA's human health and welfare risk analyses used in establishing National Ambient Air Quality Standards (NAAQS). The margin of safety for the protection of public health in the ozone rulemaking process has been established from human health risks calculated based on PRB ozone estimates. Sensitivity analyses conducted by the EPA have illustrated that changing estimates of PRB ozone concentrations have a progressively greater impact on estimates of mortality risk as more stringent standards are considered. As defined by the EPA, PRB ozone is a model construct, but it is informed by measurements at relatively remote monitoring sites (RRMS). This review examines the current understanding of PRB ozone, based on both model predictions and measurements at RRMS, and provides recommendations for improving the definition and determination of PRB ozone.

  7. Nonaqueous ozonation of vulcanized rubber

    DOEpatents

    Serkiz, Steven M.

    1999-01-01

    A process and resulting product is provided in which a solid particulate, such as vulcanized crumb rubber, has the surface functional groups oxidized by ozonation using a nonpolar solvent. The ozonation process renders the treated crumb rubber more suitable for use in new rubber formulations. As a result, larger loading levels of the treated crumb rubber can be used in new rubber mixtures.

  8. Simplified ozone detection by chemiluminescence

    NASA Technical Reports Server (NTRS)

    Conway, E. J.; Rogowski, R. S.; Richards, R. R.

    1977-01-01

    Ozone is detected by film coated with solid, such as rubrene, that reacts with ozone to degree proportional to concentration in sample gas. Gas flow is stopped, and film is heated to produce light (chemiluminescence) in proportion to amount of reacted material on sensor.

  9. Rocket ozone sounding network data

    NASA Technical Reports Server (NTRS)

    Wright, D. U.; Krueger, A. J.; Foster, G. M.

    1978-01-01

    During the period December 1976 through February 1977, three regular monthly ozone profiles were measured at Wallops Flight Center, two special soundings were taken at Antigua, West Indies, and at the Churchill Research Range, monthly activities were initiated to establish stratospheric ozone climatology. This report presents the data results and flight profiles for the period covered.

  10. Nonaqueous ozonation of vulcanized rubber

    SciTech Connect

    Serkiz, S.M.

    1999-12-07

    A process and resulting product are provided in which a solid particulate, such as vulcanized crumb rubber, has the surface functional groups oxidized by ozonation using a nonpolar solvent. The ozonation process renders the treated crumb rubber more suitable for use in new rubber formulations. As a result, larger loading levels of the treated crumb rubber can be used in new rubber mixtures.

  11. Plant responses to tropospheric ozone

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tropospheric ozone is the second most abundant air pollutant and an important component of the global climate change. Over five decades of research on the phytotoxicity of ozone in model plants systems, crop plants and forest trees have provided some insight into the physiological, biochemical and m...

  12. Rocket ozone sounding network data

    NASA Technical Reports Server (NTRS)

    Wright, D. U.; Krueger, A. J.; Foster, G. M.

    1979-01-01

    During the period March 1977 through May 1977, three regular monthly ozone profiles were measured at Wallops Flight Center and three regular monthly ozone profiles were measured at the Churchill Research Range. One additional flight was conducted at Wallops Flight Center in support of Nimbus 4 SBUV. Data results and flight profiles for the period covered are presented.

  13. Ozone Hole Not Yet Recovering

    NASA Astrophysics Data System (ADS)

    Zielinski, Sarah

    2006-08-01

    The depletion of ozone in the stratospherecaused by chemicals such as chlorofluorocarbons(CFCs)-and the resulting annualhole in the ozone layer over Antarctica-isnot getting any worse, although recovery hasnot yet begun, according to two of the scientistswho discovered the cause of the ozonehole 20 years ago.

  14. Source attribution of tropospheric ozone

    NASA Astrophysics Data System (ADS)

    Butler, T. M.

    2015-12-01

    Tropospheric ozone is a harmful pollutant with adverse effects on human health and ecosystems. As well as these effects, tropospheric ozone is also a powerful greenhouse gas, with an anthropogenic radiative forcing one quarter of that of CO2. Along with methane and atmospheric aerosol, tropospheric ozone belongs to the so-called Short Lived Climate forcing Pollutants, or SLCP. Recent work has shown that efforts to reduce concentrations of SLCP in the atmosphere have the potential to slow the rate of near-term climate change, while simultaneously improving public health and reducing crop losses. Unlike many other SLCP, tropospehric ozone is not directly emitted, but is instead influenced by two distinct sources: transport of air from the ozone-rich stratosphere; and photochemical production in the troposphere from the emitted precursors NOx (oxides of nitrogen), CO (Carbon Monoxide), and VOC (volatile organic compounds, including methane). Better understanding of the relationship between ozone production and the emissions of its precursors is essential for the development of targeted emission reduction strategies. Several modeling methods have been employed to relate the production of tropospheric ozone to emissions of its precursors; emissions perturbation, tagging, and adjoint sensitivity methods all deliver complementary information about modelled ozone production. Most studies using tagging methods have focused on attribution of tropospheric ozone production to emissions of NOx, even though perturbation methods have suggested that tropospheric ozone is also sensitive to VOC, particularly methane. In this study we describe the implementation into a global chemistry-climate model of a scheme for tagging emissions of NOx and VOC with an arbitrary number of labels, which are followed through the chemical reactions of tropospheric ozone production in order to perform attribution of tropospehric ozone to its emitted precursors. Attribution is performed to both

  15. Ozone adsorption on carbon nanoparticles

    NASA Astrophysics Data System (ADS)

    Chassard, Guillaume; Gosselin, Sylvie; Visez, Nicolas; Petitprez, Denis

    2014-05-01

    Carbonaceous particles produced by incomplete combustion or thermal decomposition of hydrocarbons are ubiquitous in the atmosphere. On these particles are adsorbed hundreds of chemical species. Those of great concern to health are polycyclic aromatic hydrocarbons (PAHs). During atmospheric transport, particulate PAHs react with gaseous oxidants. The induced chemical transformations may change toxicity and hygroscopicity of these potentially inhalable particles. The interaction between ozone and carbon particles has been extensively investigated in literature. However ozone adsorption and surface reaction mechanisms are still ambiguous. Some studies described a fast catalytic decomposition of ozone initiated by an atomic oxygen chemisorption followed by a molecular oxygen release [1-3]. Others suggested a reversible ozone adsorption according to Langmuir-type behaviour [4,5]. The aim of this present study is a better understanding of ozone interaction with carbon surfaces. An aerosol of carbon nanoparticles was generated by flowing synthetic air in a glass tube containing pure carbon (primary particles < 50 nm), under magnetic stirring. The aerosol was then mixed with ozone in an aerosol flow tube. Ozone uptake experiments were performed with different particles concentrations with a fixed ozone concentration. The influence of several factors on kinetics was examined: initial ozone concentration, particle size (50 nm ≤ Dp ≤ 200 nm) and competitive adsorption (with probe molecule and water). The effect of initial ozone concentration was first studied. Accordingly to literature, it has been observed that the number of gas-phase ozone molecules lost per unit particle surface area tends towards a plateau for high ozone concentration suggesting a reversible ozone adsorption according to a Langmuir mechanism. We calculated the initial reaction probability between O3 and carbon particles.An initial uptake coefficient of 1.10-4 was obtained. Similar experiments were

  16. Validation of 10 years of SAO OMI Ozone Profiles with Ozonesonde and MLS Observations

    NASA Astrophysics Data System (ADS)

    Huang, G.; Liu, X.; Chance, K.; Bhartia, P. K.

    2015-12-01

    To evaluate the accuracy and long-term stability of the SAO OMI ozone profile product, we validate ~10 years of ozone profile product (Oct. 2004-Dec. 2014) against collocated ozonesonde and MLS data. Ozone profiles as well stratospheric, tropospheric, lower tropospheric ozone columns are compared with ozonesonde data for different latitude bands, and time periods (e.g., 2004-2008/2009-2014 for without/with row anomaly. The mean biases and their standard deviations are also assessed as a function of time to evaluate the long-term stability and bias trends. In the mid-latitude and tropical regions, OMI generally shows good agreement with ozonesonde observations. The mean ozone profile biases are generally within 6% with up to 30% standard deviations. The biases of stratospheric ozone columns (SOC) and tropospheric ozone columns (TOC) are -0.3%-2.2% and -0.2%-3%, while standard deviations are 3.9%-5.8% and 14.4%-16.0%, respectively. However, the retrievals during 2009-2014 show larger standard deviations and larger temporal variations; the standard deviations increase by ~5% in the troposphere and ~2% in the stratosphere. Retrieval biases at individual levels in the stratosphere and upper troposphere show statistically significant trends and different trends for 2004-2008 and 2009-2014 periods. The trends in integrated ozone partial columns are less significant due to cancellation from various layers, except for significant trend in tropical SOC. These results suggest the need to perform time dependent radiometric calibration to maintain the long-term stability of this product. Similarly, we are comparing the OMI stratospheric ozone profiles and SOC with collocated MLS data, and the results will be reported.

  17. Fact Sheet - Managing Ozone Air Quality: Findings on Failure to Submit Elements of 1997 Ozone NAAQS State Implementation Plan

    EPA Pesticide Factsheets

    This fact sheet provides a basic overview of the May 17, 2008 notice that 11 states missed their deadlines to submit their state implementation plans (SIPs). The deadlines are for submitting complete plans showing how they will meet the 1997 ozone standard

  18. Variability of winter and summer surface ozone in Mexico City on the intraseasonal timescale

    NASA Astrophysics Data System (ADS)

    Barrett, Bradford S.; Raga, Graciela B.

    2016-12-01

    Surface ozone concentrations in Mexico City frequently exceed the Mexican standard and have proven difficult to forecast due to changes in meteorological conditions at its tropical location. The Madden-Julian Oscillation (MJO) is largely responsible for intraseasonal variability in the tropics. Circulation patterns in the lower and upper troposphere and precipitation are associated with the oscillation as it progresses eastward around the planet. It is typically described by phases (labeled 1 through 8), which correspond to the broad longitudinal location of the active component of the oscillation with enhanced precipitation. In this study we evaluate the intraseasonal variability of winter and summer surface ozone concentrations in Mexico City, which was investigated over the period 1986-2014 to determine if there is a modulation by the MJO that would aid in the forecast of high-pollution episodes. Over 1 000 000 hourly observations of surface ozone from five stations around the metropolitan area were standardized and then binned by active phase of the MJO, with phase determined using the real-time multivariate MJO index. Highest winter ozone concentrations were found in Mexico City on days when the MJO was active and in phase 2 (over the Indian Ocean), and highest summer ozone concentrations were found on days when the MJO was active and in phase 6 (over the western Pacific Ocean). Lowest winter ozone concentrations were found during active MJO phase 8 (over the eastern Pacific Ocean), and lowest summer ozone concentrations were found during active MJO phase 1 (over the Atlantic Ocean). Anomalies of reanalysis-based cloud cover and UV-B radiation supported the observed variability in surface ozone in both summer and winter: MJO phases with highest ozone concentration had largest positive UV-B radiation anomalies and lowest cloud-cover fraction, while phases with lowest ozone concentration had largest negative UV-B radiation anomalies and highest cloud

  19. Interagency comparison of iodometric methods for ozone determination

    NASA Technical Reports Server (NTRS)

    Demore, W. B.; Romanovsky, J. C.; Feldstein, M.; Mueller, P. K.; Hamming, W. J.

    1976-01-01

    The California Air Resources Board appointed an Oxidant Calibration Committee for the purpose of evaluating the accuracy of the different agency calibration procedures. The committee chose UV absorption photometry as the reference method for ozone measurement. Interagency comparisons of the various iodometric methods were conducted relative to the ultraviolet standard. The tests included versions of the iodometric methods as employed by the Air Resources Board, the Los Angeles Air Pollution Control District, and the EPA. An alternative candidate reference method for ozone measurement, gas phase titration, was also included in the test series.

  20. Proposed ozone reference models for the middle atmosphere

    NASA Astrophysics Data System (ADS)

    Keating, G. M.; Young, D. F.

    Since the publication of the last COSPAR International Reference Atmosphere (CIRA 72), large amounts of ozone data acquired from satellites have become available in addition to increasing quantities of rocketsonde, balloonsonde, Dobson, M83, and Umkehr measurements. From the available archived satellite data, models are developed for the new CIRA using 5 satellite experiments (Nimbus 7 SBUV and LIMS, AEM-2 SAGE, and SME IR and UVS) of the monthly latitudinal and altitudinal variations in the ozone mixing ratio in the middle atmosphere. Standard deviations and interannual variations are also quantified. The satellite models are shown to agree well with a previous reference model based on rocket and balloon measurements.

  1. Options to accelerate ozone recovery: ozone and climate benefits

    NASA Astrophysics Data System (ADS)

    Daniel, J. S.; Fleming, E. L.; Portmann, R. W.; Velders, G. J. M.; Jackman, C. H.; Ravishankara, A. R.

    2010-08-01

    Hypothetical reductions in future emissions of ozone-depleting substances (ODSs) and N2O are evaluated in terms of effects on equivalent effective stratospheric chlorine (EESC), globally-averaged total column ozone, and radiative forcing through 2100. Due to the established success of the Montreal Protocol, these actions can have only a fraction of the impact on ozone depletion that regulations already in force have had. If all anthropogenic ODS and N2O emissions were halted beginning in 2011, ozone is calculated to be higher by about 1-2% during the period 2030-2100 compared to a case of no additional restrictions. Direct radiative forcing by 2100 would be about 0.23 W/m2 lower from the elimination of anthropogenic N2O emissions and about 0.005 W/m2 lower from the destruction of the chlorofluorocarbon (CFC) bank. Due to the potential impact of N2O on future ozone levels, we provide an approach to incorporate it into the EESC formulation, which is used extensively in ozone depletion analyses. The ability of EESC to describe total ozone changes arising from additional ODS and N2O controls is also quantified.

  2. Nitroaromatic hydrocarbon ozonation in water. 1: Single ozonation

    SciTech Connect

    Beltran, F.J.; Encinar, J.M.; Alonso, M.A.

    1998-01-01

    Single ozonation of two nitroaromatic hydrocarbons (nitrobenzene and 2,6-dinitrotoluene) under different experimental conditions (ozone feed rate, pH, temperature, hydroxyl radical scavengers) has been studied. The absence of hydroxyl radical scavengers, pHs 7--9, and temperatures below 30 C are optimum conditions for nitroaromatic removal. Due to the importance of hydroxyl radical reactions, removal rates in natural water are much lower than those observed in laboratory ultrapure water. Rate constants of the direct reaction between ozone and nitroaromatic hydrocarbons at 20 C have been found to be lower than 6 M{sup {minus}1} s{sup {minus}1}. More than 99% of nitroaromatic removal is due to hydroxyl radical oxidation. Single ozonation of nitroaromatics can then be classified as a real advanced oxidation technology. Nitrophenols, compounds very reactive toward ozone and hydroxyl radicals, and 2,6-dinitrobenzaldehyde, identified in the single ozonation of nitrobenzene and 2,6-dinitrotoluene, respectively, are some of the first intermediates of single ozonation.

  3. Global distribution of ozone for various seasons

    NASA Technical Reports Server (NTRS)

    Koprova, L. I.

    1979-01-01

    A technique which was used to obtain a catalog of the seasonal global distribution of ozone is presented. The technique is based on the simultaneous use of 1964-1975 data on the total ozone content from a worldwide network of ozonometric stations and on the vertical ozone profile from ozone sounding stations.

  4. Is the Ozone Hole over Your Classroom?

    ERIC Educational Resources Information Center

    Cordero, Eugene C.

    2002-01-01

    Reports on a survey of first year university science students regarding their understanding of the ozone layer, ozone depletion, and the effect of ozone depletion on Australia. Suggests that better teaching resources for environmental issues such as ozone depletion and global warming are needed before improvements in student understanding can be…

  5. PILOT STUDY: International Comparison CCQM-P28: Ozone at ambient level

    NASA Astrophysics Data System (ADS)

    Viallon, Joële; Moussay, Philippe; Esler, Michael; Wielgosz, Robert; Bremser, Wolfram; Novák, Jirí; Vokoun, Miroslav; Botha, Angelique; Janse Van Rensburg, Mellisa; Zellweger, Christoph; Goldthorp, Sandra; Borowiak, Annette; Lagler, Friedrich; Walden, Jari; Malgeri, Ettore; Sassi, Maria Paola; Morillo Gomez, Pilar; Fernandez Patier, Rosalia; Galan Madruga, David; Woo, Jin-Chun; Doo Kim, Yong; Macé, Tatiana; Sutour, Christophe; Surget, Ana; Niederhauser, Bernhard; Schwaller, Daniel; Frigy, Beata; Györgyné Váraljai, Irén; Hashimoto, Shigeru; Mukai, Hitoshi; Tanimoto, Hiroshi; Ahleson, Hans Peter; Egeløv, Axel; Ladegard, Nils; Marsteen, Leif; Tørnkvist, Kjersti; Guenther, Franklin R.; Norris, James E.; Hafkenscheid, Theo L.; Van Rijn, Martin M.; Quincey, Paul; Sweeney, Bryan; Langer, Sarka; Magnusson, Bertil; Bastian, Juliana; Stummer, Volker; Fröhlich, Marina; Wolf, Andreas; Konopelko, Leonid A.; Kustikov, Yuri A.; Rumyanstev, Dmitry V.

    2006-01-01

    We report a pilot study organized within the Consultative Committee for Amount of Substance (CCQM), in which the ozone reference standards of 23 institutes have been compared to one common reference, the BIPM ozone reference standard, in a series of bilateral comparisons carried out between July 2003 and February 2005. The BIPM, which maintains as its reference standard a standard reference photometer (SRP) developed by the National Institute of Standards and Technology (NIST, United States), served as pilot laboratory. A total of 25 instruments were compared to the common reference standard, either directly (16 comparisons) or via a transfer standard (9 comparisons). The comparisons were made over the ozone mole fraction range 0 nmol/mol to 500 nmol/mol. Two reference methods for measuring ozone mole fractions in synthetic air were compared, thanks to the participation of two institutes maintaining a gas-phase titration system with traceability of measurements to primary gas standards of NO and NO2, while the 23 other instruments were based on UV absorption. In the first instance, each comparison was characterized by the two parameters of a linear equation, as well as their related uncertainties, computed with generalized least-squares regression software. Analysis of these results using the Birge ratio indicated an underestimation of the uncertainties associated with the measurement results of some of the ozone standards, particularly the NIST SRPs. As a final result of the pilot study, the difference from the reference value (BIPM-SRP27 measurement result) and its related uncertainty were calculated for each ozone standard at the two nominal ozone mole fractions of 80 nmol/mol and 420 nmol/mol. Main text. To reach the main text of this paper, click on Final Report. The final report has been peer-reviewed and approved for publication by the CCQM.

  6. Air Quality Modeling of Ozone Radical Precursors in Houston

    NASA Astrophysics Data System (ADS)

    Rappenglueck, B.; Czader, B.; Li, X.

    2013-05-01

    The Houston-Galveston area has one of the highest ozone concentrations in the U.S., often exceeding the U.S. National Ambient Air Quality Standard for ozone. Photochemical modeling of ozone formation in the Houston area generally underestimates the concentrations of free radical precursors contributing to ozone formation. Here we present modeling results using the Weather Research Forecast - Community Multiscale Air Quality (WRF-CMAQ) modeling system for the Houston-Galveston area. Meteorological parameters predicted by WRF are well simulated most of the time, including planetary boundary layer heights. Air quality simulations for the Houston-Galveston-Brazoria area using the combined WRF-SMOKE-CMAQ system showed overall good results for ozone and many other trace gases. HONO morning peaks are no longer underpredicted, on some occasions they are slightly overpredicted, which can be linked to NO2 overprediction. However, CMAQ mispredicts other trace gases like HO2, H2O2 and CH3OOH concentrations. The WRF-SMOKE-CMAQ system was also used to elucidate the relative importance of various photolysis processes as radical sources in the Houston atmosphere. Morning HOx formation is dominated by HONO while ozone contributes the most during midday. HONO contribution to HOx formation is more pronounced at the surface layer where most of it is formed. On the other hand, radical production from ozone is more important at elevated levels where higher concentrations of ozone are observed. Formaldehyde contributes up to 40% and also peaks during mid-day, but on days when high morning concentrations of formaldehyde are observed its contribution to HOx in the morning exceeds that of ozone. Photolysis of H2O2 is a minor contributor to radical levels. The process analysis tool available in CMAQ was utilized to analyze photochemical processes leading to ozone production and chemical transformations along trajectories linking a site at the Houston Ship Channel and the University of

  7. Spatial and temporal patterns of ozone in the high elevation ecosystems of the Colorado Rocky Mountains

    NASA Astrophysics Data System (ADS)

    Liptzin, D.; Helmig, D.

    2015-12-01

    Tropospheric ozone is regulated by the US EPA to protect human health and welfare. Because the precursors to ozone formation largely come from transportation and industrial activity, ozone has typically been thought of as an urban pollution problem. However, there is growing concern about increased ozone concentrations in rural areas. Surprisingly high ozone concentrations have been measured in the high elevation Rocky Mountain ecosystems in the Front Range of Colorado. The annual median ozone mixing ratios over the past decade at three high elevation monitoring stations ranged from 47 to 53 ppbv. The hourly ozone mixing ratio typically exceeds 100 ppbv at some point every year at these sites. The number of days where the ozone mixing ratio exceeded the current 8 hour US EPA National Ambient Air Quality Standard of 75 ppb has ranged from 0 to 25 since 1987 at the monitoring site in Rocky Mountain National Park. A comparison with lower elevation sites suggests that ozone mixing ratios generally increase with elevation. In addition, the diurnal and seasonal variability of ozone decreases with elevation. Along an elevational gradient from the plains to the tundra, the tundra site had the highest median values and the least variability of any site. The seasonal pattern at these high elevation sites is also distinct as the maximum mixing ratios occur in the spring in contrast to the summer maximum typically observed in urban areas. While there have been relatively small changes in concentration in the measured data record going back a few decades, modeling suggests that ozone mixing ratios have almost doubled over the last one hundred years in Colorado. A plethora of studies has shown that elevated ozone damages foliage, with sensitive species showing effect at levels exceeding 35-40 ppbv. Since ozone levels in these high elevation ecosystems are clearly above that, we believe that they have been and will continue to be severely affected by elevated ozone. It is not

  8. Total ozone changes in the 1987 Antarctic ozone hole

    NASA Technical Reports Server (NTRS)

    Krueger, Arlin J.; Schoeberl, Mark R.; Doiron, Scott D.; Sechrist, Frank; Galimore, Reginald

    1988-01-01

    The development of the Antarctic ozone minimum was observed in 1987 with the Nimbus 7 Total Ozone Mapping Spectrometer (TOMS) instrument. In the first half of August the near-polar (60 and 70 deg S) ozone levels were similar to those of recent years. By September, however, the ozone at 70 and 80 deg S was clearly lower than any previous year including 1985, the prior record low year. The levels continued to decrease throughout September until October 5 when a new record low of 109 DU was established at a point near the South Pole. This value is 29 DU less than the lowest observed in 1985 and 48 DU less than the 1986 low. The zonal mean total ozone at 60 deg S remained constant throughout the time of ozone hole formation. The ozone decline was punctuated by local minima formed away from the polar night boundary at about 75 deg S. The first of these, on August 15 to 17, formed just east of the Palmer Peninsula and appears to be a mountain wave. The second major minimum formed on September 5 to 7 again downwind of the Palmer Peninsula. This event was larger in scale than the August minimum and initiated the decline of ozone across the polar region. The 1987 ozone hole was nearly circular and pole centered for its entire life. In previous years the hole was perturbed by intrusions of the circumpolar maximum into the polar regions, thus causing the hole to be elliptical. The 1987 hole also remained in place until the end of November, a few days longer than in 1985, and this persistence resulted in the latest time for recovery to normal values yet observed.

  9. Probabilistic Forecasting of Surface Ozone with a Novel Statistical Approach

    NASA Technical Reports Server (NTRS)

    Balashov, Nikolay V.; Thompson, Anne M.; Young, George S.

    2017-01-01

    The recent change in the Environmental Protection Agency's surface ozone regulation, lowering the surface ozone daily maximum 8-h average (MDA8) exceedance threshold from 75 to 70 ppbv, poses significant challenges to U.S. air quality (AQ) forecasters responsible for ozone MDA8 forecasts. The forecasters, supplied by only a few AQ model products, end up relying heavily on self-developed tools. To help U.S. AQ forecasters, this study explores a surface ozone MDA8 forecasting tool that is based solely on statistical methods and standard meteorological variables from the numerical weather prediction (NWP) models. The model combines the self-organizing map (SOM), which is a clustering technique, with a step wise weighted quadratic regression using meteorological variables as predictors for ozone MDA8. The SOM method identifies different weather regimes, to distinguish between various modes of ozone variability, and groups them according to similarity. In this way, when a regression is developed for a specific regime, data from the other regimes are also used, with weights that are based on their similarity to this specific regime. This approach, regression in SOM (REGiS), yields a distinct model for each regime taking into account both the training cases for that regime and other similar training cases. To produce probabilistic MDA8 ozone forecasts, REGiS weighs and combines all of the developed regression models on the basis of the weather patterns predicted by an NWP model. REGiS is evaluated over the San Joaquin Valley in California and the northeastern plains of Colorado. The results suggest that the model performs best when trained and adjusted separately for an individual AQ station and its corresponding meteorological site.

  10. Chlorine catalyzed destruction of ozone: Implications for ozone variability in the upper stratosphere

    SciTech Connect

    Chandra, S.; Jackman, C.H.; Douglass, A.R. ); Fleming, E.L.; Considine, D.B. )

    1993-03-05

    The annual mean and the annual amplitude of ozone have been derived from ozone measurements from the SBUV and SBUV/2 spectrometers on board the Nimbus-7 and NOAA-11 satellites. These values differ significantly from values calculated using a two-dimensional model of stratospheric photochemistry and dynamics with standard chemistry. The authors have found that the differences between the calculated and data-derived values are considerably improved by changing the partitioning in the Cl[sub y] family to create a larger reservoir of HCl and reducing ClO. This is accomplished by including a channel for the products HCl+O[sub 2], from the reaction ClO+OH in addition to the products Cl+HO[sub 2]. This partitioning also improves the agreement between the calculated and measured values or ClO/HCl ratio. 18 refs., 6 figs.

  11. Unprecedented Arctic ozone loss in 2011.

    PubMed

    Manney, Gloria L; Santee, Michelle L; Rex, Markus; Livesey, Nathaniel J; Pitts, Michael C; Veefkind, Pepijn; Nash, Eric R; Wohltmann, Ingo; Lehmann, Ralph; Froidevaux, Lucien; Poole, Lamont R; Schoeberl, Mark R; Haffner, David P; Davies, Jonathan; Dorokhov, Valery; Gernandt, Hartwig; Johnson, Bryan; Kivi, Rigel; Kyrö, Esko; Larsen, Niels; Levelt, Pieternel F; Makshtas, Alexander; McElroy, C Thomas; Nakajima, Hideaki; Parrondo, Maria Concepción; Tarasick, David W; von der Gathen, Peter; Walker, Kaley A; Zinoviev, Nikita S

    2011-10-02

    Chemical ozone destruction occurs over both polar regions in local winter-spring. In the Antarctic, essentially complete removal of lower-stratospheric ozone currently results in an ozone hole every year, whereas in the Arctic, ozone loss is highly variable and has until now been much more limited. Here we demonstrate that chemical ozone destruction over the Arctic in early 2011 was--for the first time in the observational record--comparable to that in the Antarctic ozone hole. Unusually long-lasting cold conditions in the Arctic lower stratosphere led to persistent enhancement in ozone-destroying forms of chlorine and to unprecedented ozone loss, which exceeded 80 per cent over 18-20 kilometres altitude. Our results show that Arctic ozone holes are possible even with temperatures much milder than those in the Antarctic. We cannot at present predict when such severe Arctic ozone depletion may be matched or exceeded.

  12. Effects of stratospheric ozone recovery on photochemistry and ozone air quality in the troposphere

    NASA Astrophysics Data System (ADS)

    Zhang, H.; Wu, S.; Huang, Y.; Wang, Y.

    2014-04-01

    There has been significant stratospheric ozone depletion since the late 1970s due to ozone-depleting substances (ODSs). With the implementation of the Montreal Protocol and its amendments and adjustments, stratospheric ozone is expected to recover towards its pre-1980 level in the coming decades. In this study, we examine the implications of stratospheric ozone recovery for the tropospheric chemistry and ozone air quality with a global chemical transport model (GEOS-Chem). With a full recovery of the stratospheric ozone, the projected increases in ozone column range from 1% over the low latitudes to more than 10% over the polar regions. The sensitivity factor of troposphere ozone photolysis rate, defined as the percentage changes in surface ozone photolysis rate for 1% increase in stratospheric ozone column, shows significant seasonal variation but is always negative with absolute value larger than one. The expected stratospheric ozone recovery is found to affect the tropospheric ozone destruction rates much more than the ozone production rates. Significant decreases in surface ozone photolysis rates due to stratospheric ozone recovery are simulated. The global average tropospheric OH decreases by 1.7%, and the global average lifetime of tropospheric ozone increases by 1.5%. The perturbations to tropospheric ozone and surface ozone show large seasonal and spatial variations. General increases in surface ozone are calculated for each season, with increases by up to 0.8 ppbv in the remote areas. Increases in ozone lifetime by up to 13% are found in the troposphere. The increased lifetimes of tropospheric ozone in response to stratospheric ozone recovery enhance the intercontinental transport of ozone and global pollution, in particular for the summertime. The global background ozone attributable to Asian emissions is calculated to increase by up to 15% or 0.3 ppbv in the Northern Hemisphere in response to the projected stratospheric ozone recovery.

  13. Error in total ozone measurements arising from aerosol attenuation

    NASA Technical Reports Server (NTRS)

    Thomas, R. W. L.; Basher, R. E.

    1979-01-01

    A generalized least squares method for deducing both total ozone and aerosol extinction spectrum parameters from Dobson spectrophotometer measurements was developed. An error analysis applied to this system indicates that there is little advantage to additional measurements once a sufficient number of line pairs have been employed to solve for the selected detail in the attenuation model. It is shown that when there is a predominance of small particles (less than about 0.35 microns in diameter) the total ozone from the standard AD system is too high by about one percent. When larger particles are present the derived total ozone may be an overestimate or an underestimate but serious errors occur only for narrow polydispersions.

  14. An evaluation of electrochemical concentration cell sonde measurements of atmospheric ozone

    NASA Technical Reports Server (NTRS)

    Geraci, M. J.; Luers, J. K.

    1978-01-01

    Using Dobson spectrophotometer measurements of total ozone as a comparison, an analysis of the Electrochemical Concentration Cell (ECC) ozonesonde's measurement accuracy is presented. Days of conjunctive ECC-Dobson observations (from 1970 to 1976 at Wallops Flight Center) provide a set of 123 pairs of total ozone values. Sample set statistics are generated with means and standard deviations of total ozone values and differences being noted. An in-depth study of factors such as time differences between associated observations, integration techniques used, assumptions used in calculating residual ozone and other possible sources of errors are examined. Short-period changes in total ozone using Dobson data during the observational period are also described.

  15. Trends in ozone profile measurements

    NASA Technical Reports Server (NTRS)

    Johnston, H.; Aikin, A.; Barnes, R.; Chandra, S.; Cunnold, D.; Deluisi, J.; Gille, J. C.; Hudson, R.; Mccormick, M. P.; Mcmaster, L.

    1989-01-01

    From an examination of the agreements and differences between different satellite instruments, it is difficult to believe that existing satellite instruments determine upper stratospheric ozone much better than 4 pct.; by extension, it probably would require at least a 4 pct. change to be reliably detected as a change. The best estimates of the vertical profiles of ozone change in the upper stratosphere between 1979 and 1986 are judged to be those given by the two SAGE satellite instruments. SAGE-2 minus SAGE-1 gives a much lower ozone reduction than that given by the archived Solar Backscatter UV data. The average SAGE profiles of ozone changes between 20 and 50 degs north and between 20 and 50 degs south are given. The SAGE-1 and SAGE-2 comparison gives an ozone reduction of about 4 pct. at 25 km over temperate latitudes. Five ground based Umkehr stations between 36 and 52 degs north, corrected for the effects of volcanic aerosols, report an ozone reduction between 1979 and 1987 at Umkehr layer 8 of 9 + or - 5 pct. The central estimate of upper stratospheric ozone reduction given by SAGE at 40 km is less than the central value estimated by the Umkehr method at layer 8.

  16. Total ozone trend over Cairo

    NASA Technical Reports Server (NTRS)

    Hassan, G. K. Y.

    1994-01-01

    A world wide interest in protecting ozone layer against manmade effects is now increasing. Assessment of the ozone depletion due to these activities depends on how successfully we can separate the natural variabilities from the data. The monthly mean values of total ozone over Cairo (30 05N) for the period 1968-1988, have been analyzed using the power spectral analysis technique. The technique used in this analysis does not depend on a pre-understanding of the natural fluctuations in the ozone data. The method depends on increasing the resolution of the spectral peaks in order to obtain the more accurate sinusoidal fluctuations with wavelength equal to or less than record length. Also it handles the possible sinusoidal fluctuations with wavelength equal to or less than record length. The results show that it is possible to detect some of the well known national fluctuations in the ozone record such as annual, semiannual, quasi-biennial and quasi-quadrennial oscillations. After separating the natural fluctuations from the ozone record, the trend analysis of total ozone over Cairo showed that a decrease of about -1.2% per decade has occurred since 1979.

  17. Ozone is mutagenic in Salmonella

    SciTech Connect

    Dillon, D.; Combes, R.; McConville, M.; Zeiger, E. )

    1992-01-01

    Ozone is a highly reactive gas that has been tested for genotoxicity in a number of systems. Induced genetic damage resulting from ozone treatment may not be readily observed because of the high toxicity of the chemical and difficulties in generating and administering controlled concentrations. The mutagenicity of ozone was investigated in Salmonella typhimurium using a plate test protocol designed for reactive vapours and gases. Ozone, at two to three consecutive doses, induced weak, albeit statistically significant, mutagenic responses in tester strain TA102 with and without Aroclor-induced rat liver S9 (lowest effective mean concentration of 0.019 ppm; 35 min total exposure). However, dose-related responses were not always obtained. No mutagenicity was detected in strains TA98, TA100, or TA1535, with or without S9. In strain TA104, ozone induced a weak response only at a single dose with S9; this response was not reproducible. Mutagenicity was dependent on the ozone flow rate and total exposure time, with variations in the optimum dose-time regimen leading to toxicity or complete inactivity. The data show that ozone is a very weak bacterial mutagen and only when tested under narrowly prescribed, subtoxic dosing conditions.

  18. Southern Hemisphere Additional Ozonesondes (SHADOZ) 1998-2000 tropical ozone climatology 1. Comparison with Total Ozone Mapping Spectrometer (TOMS) and ground-based measurements

    NASA Astrophysics Data System (ADS)

    Thompson, Anne M.; Witte, Jacquelyn C.; McPeters, Richard D.; Oltmans, Samuel J.; Schmidlin, Francis J.; Logan, Jennifer A.; Fujiwara, Masatomo; Kirchhoff, Volker W. J. H.; Posny, FrançOise; Coetzee, Gert J. R.; Hoegger, Bruno; Kawakami, Shuji; Ogawa, Toshihiro; Johnson, Bryan J.; VöMel, Holger; Labow, Gordon

    2003-01-01

    A network of 10 southern hemisphere tropical and subtropical stations, designated the Southern Hemisphere Additional Ozonesondes (SHADOZ) project and established from operational sites, provided over 1000 ozone profiles during the period 1998-2000. Balloon-borne electrochemical concentration cell (ECC) ozonesondes, combined with standard radiosondes for pressure, temperature, and relative humidity measurements, collected profiles in the troposphere and lower to midstratosphere at: Ascension Island; Nairobi, Kenya; Irene, South Africa; Réunion Island; Watukosek, Java; Fiji; Tahiti; American Samoa; San Cristóbal, Galapagos; and Natal, Brazil. The archived data are available at: . In this paper, uncertainties and accuracies within the SHADOZ ozone data set are evaluated by analyzing: (1) imprecisions in profiles and in methods of extrapolating ozone above balloon burst; (2) comparisons of column-integrated total ozone from sondes with total ozone from the Earth-Probe/Total Ozone Mapping Spectrometer (TOMS) satellite and ground-based instruments; and (3) possible biases from station to station due to variations in ozonesonde characteristics. The key results are the following: (1) Ozonesonde precision is 5%. (2) Integrated total ozone column amounts from the sondes are usually to within 5% of independent measurements from ground-based instruments at five SHADOZ sites and overpass measurements from the TOMS satellite (version 7 data). (3) Systematic variations in TOMS-sonde offsets and in ground-based-sonde offsets from station to station reflect biases in sonde technique as well as in satellite retrieval. Discrepancies are present in both stratospheric and tropospheric ozone. (4) There is evidence for a zonal wave-one pattern in total and tropospheric ozone, but not in stratospheric ozone.

  19. A Long Data Record (1979-2003) of Stratospheric Ozone Derived from TOMS Cloud Slicing: Comparison with SAGE and Implications for Ozone Recovery

    NASA Technical Reports Server (NTRS)

    Ziemke, Jerry R.; Chandra, Sushil; Bhartia, Pawan K.

    2004-01-01

    It is generally recognized that Stratospheric Aerosols and Gas Experiment (SAGE) stratospheric ozone data have become a standard long-record reference field for comparison with other stratospheric ozone measurements. This study demonstrates that stratospheric column ozone (SCO) derived from total ozone mapping spectrometer (TOMS) Cloud Slicing may be used to supplement SAGE data as a stand-alone long- record reference field in the tropics extending to middle and high latitudes over the Pacific. Comparisons of SAGE I1 version 6.2 SCO and TOMS version 8 Cloud Slicing SCO for 1984-2003 exhibit remarkable agreement in monthly ensemble means to within 1-3 DU (1 - 1.5% of SCO) despite being independently-calibrated measurements. An important component of our study is to incorporate these column ozone measurements to investigate long-term trends for the period 1979-2003. Our study includes Solar Backscatter Ultraviolet (SBW) version 8 measurements of upper stratospheric column ozone (i.e., zero to 32 hPa column ozone) to characterize seasonal cycles and seasonal trends in this region, as well as the lower stratosphere and troposphere when combined with TOMS SCO and total column ozone. The trend analyses suggest that most ozone reduction in the atmosphere since 1979 in mid-to-high latitudes has occurred in the Lower stratosphere below approx. 25 km. The delineation of upper and lower stratospheric column ozone indicate that trends in the upper stratosphere during the latter half of the 1979-2003 period have reduced to near zero globally, while trends in the lower stratosphere have become larger by approx. 5 DU decade%om the tropics extending to mid-latitudes in both hemispheres. For TCO, the trend analyses suggest moderate increases over the 25-year time record in the extra-tropics of both hemispheres of around 4-6 DU (Northern Hemisphere) and 6-8 DU (Southern Hemisphere).

  20. The usefulness of ozone treatment in spinal pain

    PubMed Central

    Bocci, Velio; Borrelli, Emma; Zanardi, Iacopo; Travagli, Valter

    2015-01-01

    Objective The aim of this review is to elucidate the biochemical, molecular, immunological, and pharmaceutical mechanisms of action of ozone dissolved in biological fluids. Studies performed during the last two decades allow the drawing of a comprehensive framework for understanding and recommending the integration of ozone therapy for spinal pain. Methods An in-depth screening of primary sources of information online – via SciFinder Scholar, Google Scholar, and Scopus databases as well as Embase, PubMed, and the Cochrane Database of Systemic Reviews – was performed. In this review, the most significant papers of the last 25 years are presented and their proposals critically evaluated, regardless of the bibliometric impact of the journals. Results The efficacy of standard treatments combined with the unique capacity of ozone therapy to reactivate the innate antioxidant system is the key to correcting the oxidative stress typical of chronic inflammatory diseases. Pain pathways and control systems of algesic signals after ozone administration are described. Conclusion This paper finds favors the full insertion of ozone therapy into pharmaceutical sciences, rather than as either an alternative or an esoteric approach. PMID:26028964

  1. Ozone production at the National Synchrotron Light Source

    SciTech Connect

    Weilandics, C.; Rohrig, N.; Gmur, N.F.

    1987-01-01

    Ozone production by synchrotron radiation as a function of power density in air was investigated using a white beam at the BNL National Synchrotron Light Source (NSLS) x-ray ring. Power densities were calculated from the energy spectrum at 2.52 GeV. Ozone concentrations in small beam pipes were measured for power densities between I = 10/sup 12/ and 10/sup 15/ eV . cm/sup -3/ . sec/sup -1/. The measured ozone half-life was 37 +- 2 min. The measured G-value was 2.69 +- 0.14 mol/100 eV and the ozone destruction factor k was less than 7 x 10/sup -19/ cm/sup 3/ . eV/sup -1/. The random uncertainties stated are approximately one standard error. The large departure of the values for G and k from previous values suggest that some undiscovered systematic error may exist in the experiment. Ozone concentration in excess of the 0.1 ppM ACGIH TLV can be generated in the experimental hutches but can readily be controlled. Industrial hygiene aspects of operation and possible control measures will be discussed. 19 refs., 7 figs., 3 tabs.

  2. Sensitivity Studies for Assimilated Ozone Profiles

    NASA Technical Reports Server (NTRS)

    Stajner, Ivanka; Winslow, Nathan; Wargan, Krzysztof; Rood, Richard; Pawson, Steven

    2002-01-01

    An ozone data assimilation system at the NASA/Goddard Data Assimilation Office (DAO) produces three-dimensional global ozone fields. They are obtained by assimilating ozone retrieved from the Solar Backscatter UltraViolet/2 (SBUV/2) instrument and the Earth Probe Total Ozone Mapping Spectrometer (EP TOMS) measurements into an off-line parameterized chemistry and transport model. In this talk we focus on the quality of lower stratospheric assimilated ozone profiles. Ozone in the lower stratosphere plays a key role in the forcing of climate. A biased ozone field in this region will adversely impact calculations of the stratosphere-troposphere exchange and, when used as a first guess in retrievals, the values determined from satellite observations. The SBUV/2 ozone data have a coarse vertical resolution with increased uncertainty below the ozone maximum, and TOMS provides only total ozone columns. Thus, the assimilated ozone profiles in the lower stratosphere are only weakly constrained by the incoming SBUV and TOMS data. Consequently, the assimilated ozone distribution should be sensitive to changes in inputs to the statistical analysis scheme. We investigate the sensitivity of assimilated ozone profiles to changes in a variety of system inputs: TOMS and SBUV/2 data selection, forecast and observations error covariance models, inclusion or omission of a parameterized chemistry model, and different versions of DAO assimilated wind fields used to drive the transport model. Comparisons of assimilated ozone fields with independent observations, primarily ozone sondes, are used to determine the impact of each of these changes.

  3. Diagnosing changes in European tropospheric ozone: A model study of past and future changes

    NASA Astrophysics Data System (ADS)

    Tummon, Fiona; Revell, Laura; Stenke, Andrea; Staehelin, Johannes; Peter, Thomas

    2016-04-01

    In recent decades, the negative impacts of tropospheric ozone on human and ecosystem health have led to policy changes aimed at reducing emissions of ozone precursor gases such as nitrogen oxides (NOx) and carbon monoxide (CO). Although emissions of these species have significantly decreased in Europe and North America since the early 1990s, observational data indicate that free tropospheric ozone over Europe has not decreased as expected. Uncertainty remains as to how much of a role the transport of stratospheric ozone or tropospheric ozone from remote source regions has played in recent trends, as well as to how this will evolve in a changing climate. The global chemistry-climate model SOCOL (SOlar Chemistry Ozone Links) is used to investigate tropospheric ozone over Europe from 1960 to 2100. To fully disentangle the effects of both long-range transport and input from the stratosphere, simulations are run with ozone tracers from 21 different atmospheric regions. In addition to a standard reference run, several sensitivity simulations are run: one with emissions of NOx and CO held constant at 1960 levels, one with methane (CH4) held at constant 1960 levels (in addition to the NOx and CO), and a third with NOx and CO emissions from Asia fixed at 1960 levels. Results suggest that the largest contributions to European tropospheric ozone originate from the tropical and northern mid-latitude boundary layer and free troposphere. Contributions from these regions increase over the historical period (1960-2010), indicating that changes in source gas emissions have affected ozone concentrations in the European free troposphere most strongly. Contributions from these regions then decrease from 2010-2100, but remain considerably larger than input from the stratosphere, which is relatively small in all simulations throughout the entire simulated period (1960-2100). The stratospheric contribution does, however, increase slightly over the 21st century, in tandem with ozone

  4. Combined Effect of Ultrasound and Ozone on Bacteria in Water.

    PubMed

    Al-Hashimi, Amna M; Mason, Timothy J; Joyce, Eadaoin M

    2015-10-06

    The aim of this study is to assess the synergetic effect of combined ultrasound and ozone treatment on the biological disinfection of water on a large-scale application using viable plate counts and flow cytometry. Escherichia coli B bacteria in saline suspension was treated using a commercially available combined ultrasound and ozone system (USO3 (Ultrasonic Systems Gmbh)) for 16 min. Two analytical methods were used to assess the results in terms of live and dead cells in the bulk liquid: standard viable plate counting recorded in terms of colony forming units per milliliter and flow cytometry. In the latter case 1 mL of bacterial suspension was stained simultaneously with the fluorescent stains SYTO9 and propidium iodide (PI). Transmission electron microscopy was used to generate images identifying the biological effects of different treatments using ultrasound and ozone on bacterial cell walls. Results demonstrated that treatment with ozone alone (1 mg/L) resulted in a significant reduction (93%) in the number of live cells after 16 min treatment whereas ultrasound alone showed only a small reduction (24%). However, a combination of ozone and ultrasound showed a synergistic effect and enhanced the inactivation to 99% after 4 min. A combined ultrasound and ozone treatment of bacterial suspensions using a commercial system affords a promising method for water disinfection that is better than treatment using either method alone. Standard viable plate count analysis is normally used to assess the effectiveness of disinfection treatments; however flow cytometry proved to be a more sensitive method to determine the actual effects in terms of not only live and dead cells but also damaged cells. This type of analysis (cell damage) is difficult if not impossible to achieve using traditional plate counting methodology.

  5. Urban greening impacts on tropospheric ozone

    NASA Astrophysics Data System (ADS)

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

    2013-12-01

    investigate the tradeoff between vegetation driven ozone -reduction and -formation processes in dependence on temperature, radiation, CO2 and O3 concentrations. We have parameterized suitable plant functional types for different urban greening structures, currently focusing on central European vegetation. The modified CLM model is applied in a global (CESM) and a regional climate/ air quality model (WRF-Chem) to calculate realistic ozone concentrations in the influence zones of urban conglomerations. BVOC emissions and their impacts are also calculated with the standard MEGAN2.1 approach for comparison. The simulation results are analyzed and discussed in view of the models suitability for air quality scenario estimates under simultaneously changing climate, anthropogenic emissions and plant species composition. References Morfopoulos, C., Prentice, I.C., Keenan T.F., Friedlingstein, P., Medlyn, B., Penuelas, J., Possel, M. (in press): A unifying conceptual model for the environmental responses of isoprene emission by plants. Annals of Botany

  6. Modeling Stomatal Conductance to Estimate Seasonal Uptake in the Ozone-Sensitive Bioindicator Plant Common Milkweed (A. syriaca L.)

    NASA Astrophysics Data System (ADS)

    Bergweiler, C.

    2008-12-01

    The US EPA National Ambient Air Quality Standard (NAAQS) was not conceived to nor does it provide an accurate definition of the absorbed ozone dose or baseline exposure level to protect vegetation. This research presents a multiplicative modeling approach based not only on atmospheric, but on equally important physiological, phenological, and environmental parameters. Physiological constraints on ozone uptake demonstrate that actual absorption is substantially lower than that assumed by a simple interpretation of hourly atmospheric ozone concentrations. Coupled with development of foliar injury expression this provides evidence that tropospheric ozone is more toxic to vegetation than is currently understood.

  7. 75 FR 79302 - Determination of Nonattainment and Reclassification of the Dallas/Fort Worth 1997 8-Hour Ozone...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-20

    ...-Hour Ozone Nonattainment Area; Texas AGENCY: Environmental Protection Agency (EPA). ACTION: Final rule... nonattainment area failed to attain the 1997 8-hour ozone national ambient air quality standard (NAAQS or... Federal Regulations (CFR) for moderate nonattainment areas. This final determination is based on...

  8. Ozone and Ozonated Oils in Skin Diseases: A Review

    PubMed Central

    Travagli, V.; Zanardi, I.; Valacchi, G.; Bocci, V.

    2010-01-01

    Although orthodox medicine has provided a variety of topical anti-infective agents, some of them have become scarcely effective owing to antibiotic- and chemotherapeutic-resistant pathogens. For more than a century, ozone has been known to be an excellent disinfectant that nevertheless had to be used with caution for its oxidizing properties. Only during the last decade it has been learned how to tame its great reactivity by precisely dosing its concentration and permanently incorporating the gas into triglycerides where gaseous ozone chemically reacts with unsaturated substrates leading to therapeutically active ozonated derivatives. Today the stability and efficacy of the ozonated oils have been already demonstrated, but owing to a plethora of commercial products, the present paper aims to analyze these derivatives suggesting the strategy to obtain products with the best characteristics. PMID:20671923

  9. Dobson spectrophotometer ozone measurements during international ozone rocketsonde intercomparison

    NASA Technical Reports Server (NTRS)

    Parsons, C. L.

    1980-01-01

    Measurements of the total ozone content of the atmosphere, made with seven ground based instruments at a site near Wallops Island, Virginia, are discussed in terms for serving as control values with which the rocketborne sensor data products can be compared. These products are profiles of O3 concentration with altitude. By integrating over the range of altitudes from the surface to the rocket apogee and by appropriately estimating the residual ozone amount from apogee to the top of the atmosphere, a total ozone amount can be computed from the profiles that can be directly compared with the ground based instrumentation results. Dobson spectrophotometers were used for two of the ground-based instruments. Preliminary data collected during the IORI from Dobson spectrophotometers 72 and 38 are presented. The agreement between the two and the variability of total ozone overburden through the experiment period are discussed.

  10. Ozone and ozonated oils in skin diseases: a review.

    PubMed

    Travagli, V; Zanardi, I; Valacchi, G; Bocci, V

    2010-01-01

    Although orthodox medicine has provided a variety of topical anti-infective agents, some of them have become scarcely effective owing to antibiotic- and chemotherapeutic-resistant pathogens. For more than a century, ozone has been known to be an excellent disinfectant that nevertheless had to be used with caution for its oxidizing properties. Only during the last decade it has been learned how to tame its great reactivity by precisely dosing its concentration and permanently incorporating the gas into triglycerides where gaseous ozone chemically reacts with unsaturated substrates leading to therapeutically active ozonated derivatives. Today the stability and efficacy of the ozonated oils have been already demonstrated, but owing to a plethora of commercial products, the present paper aims to analyze these derivatives suggesting the strategy to obtain products with the best characteristics.

  11. Analysis of error in TOMS total ozone as a function of orbit and attitude parameters

    NASA Technical Reports Server (NTRS)

    Gregg, W. W.; Ardanuy, P. E.; Braun, W. C.; Vallette, B. J.; Bhartia, P. K.; Ray, S. N.

    1991-01-01

    Computer simulations of orbital scenarios were performed to examine the effects of orbital altitude, equator crossing time, attitude uncertainty, and orbital eccentricity on ozone observations by future satellites. These effects were assessed by determining changes in solar and viewing geometry and earth daytime coverage loss. The importance of these changes on ozone retrieval was determined by simulating uncertainties in the TOMS ozone retrieval algorithm. The major findings are as follows: (1) Drift of equator crossing time from local noon would have the largest effect on the quality of ozone derived from TOMS. The most significant effect of this drift is the loss of earth daytime coverage in the winter hemisphere. The loss in coverage increases from 1 degree latitude for + or - 1 hour from noon, 6 degrees for + or - 3 hours from noon, to 53 degrees for + or - 6 hours from noon. An additional effect is the increase in ozone retrieval errors due to high solar zenith angles. (2) To maintain contiguous earth coverage, the maximum scan angle of the sensor must be increased with decreasing orbital altitude. The maximum scan angle required for full coverage at the equator varies from 60 degrees at 600 km altitude to 45 degrees at 1200 km. This produces an increase in spacecraft zenith angle, theta, which decreases the ozone retrieval accuracy. The range in theta was approximately 72 degrees for 600 km to approximately 57 degrees at 1200 km. (3) The effect of elliptical orbits is to create gaps in coverage along the subsatellite track. An elliptical orbit with a 200 km perigee and 1200 km apogee produced a maximum earth coverage gap of about 45 km at the perigee at nadir. (4) An attitude uncertainty of 0.1 degree in each axis (pitch, roll, yaw) produced a maximum scan angle to view the pole, and maximum solar zenith angle).

  12. Inhibitory effect of hydrogen sulfide on ozone-induced airway inflammation, oxidative stress, and bronchial hyperresponsiveness.

    PubMed

    Zhang, Pengyu; Li, Feng; Wiegman, Coen H; Zhang, Min; Hong, Yan; Gong, Jicheng; Chang, Yan; Zhang, Junfeng Jim; Adcock, Ian; Chung, Kian Fan; Zhou, Xin

    2015-01-01

    Exposure to ozone has been associated with airway inflammation, oxidative stress, and bronchial hyperresponsiveness. The goal of this study was to examine whether these adverse effects of ozone could be prevented or reversed by hydrogen sulfide (H2S) as a reducing agent. The H2S donor sodium (NaHS) (2 mg/kg) or vehicle (PBS) was intraperitoneally injected into mice 1 hour before and after 3-hour ozone (2.5 ppm) or air exposure, and the mice were studied 24 hours later. Preventive and therapeutic treatment with NaHS reduced the ozone-induced increases in the total cells, including neutrophils and macrophages; this treatment also reduced levels of cytokines, including TNF-α, chemokine (C-X-C motif) ligand 1, IL-6, and IL-1β levels in bronchial alveolar lavage fluid; inhibited bronchial hyperresponsiveness; and attenuated ozone-induced increases in total malondialdehyde in bronchoalveolar lavage fluid and decreases in the ratio of reduced glutathione/oxidized glutathione in the lung. Ozone exposure led to decreases in the H2S production rate and in mRNA and protein levels of cystathionine-β-synthetase and cystathionine-γ-lyase in the lung. These effects were prevented and reversed by NaHS treatment. Furthermore, NaHS prevented and reversed the phosphorylation of p38 mitogen-activated protein kinase and heat shock protein 27. H2S may have preventive and therapeutic value in the treatment of airway diseases that have an oxidative stress basis.

  13. Development of Ozone Technology Rice Storage Systems (OTRISS) for Quality Improvement of Rice Production

    NASA Astrophysics Data System (ADS)

    Nur, M.; Kusdiyantini, E.; Wuryanti, W.; Winarni, T. A.; Widyanto, S. A.; Muharam, H.

    2015-06-01

    This research has been carried out by using ozone to address the rapidly declining quality of rice in storage. In the first year, research has focused on the rice storage with ozone technology for small capacity (e.g., household) and the medium capacity (e.g., dormitories, hospitals). Ozone was produced by an ozone generator with Dielectric Barrier Discharge Plasma (DBDP). Ozone technology rice storage system (OTRISS) is using ozone charateristic which is a strong oxidizer. Ozone have a short endurance of existence and then decompose, as a result produce oxygen and radicals of oxygen. These characteristics could kill microorganisms and pests, reduce air humidity and enrich oxygen. All components used in SPBTO assembled using raw materials available in the big cities in Indonesia. Provider of high voltage (High Voltage Power Supply, 40-70 kV, 23 KH, AC) is one of components that have been assembled and tested. Ozone generator is assembled with 7 reactors of Dielectric Barrier Discharge Plasma (DBDP). Rice container that have been prepared for OTRISS have adjusted so can be integrated with generator, power supply and blower to blow air. OTRISS with a capacity of 75 kg and 100 kg have been made and tested. The ability of ozone to eliminate bacteria and fungi have been tested and resulted in a decrease of microorganisms at 3 log CFU/g. Testing in food chemistry showed that ozone treatment of rice had not changed the chemical content that still meet the standard of chemical content and nutritional applicable to ISO standard milled rice. The results of this study are very likely to be used as an alternative to rice storage systems in warehouse. Test and scale-up is being carried out in a mini warehouse whose condition is mimicked to rice in National Rice Storage of Indonesia (Bulog) to ensure quality. Next adaptations would be installed in the rice storage system in the Bulog.

  14. Observational constraints on ozone radiative forcing from the Atmospheric Chemistry Climate Model Intercomparison Project (ACCMIP)

    NASA Astrophysics Data System (ADS)

    Bowman, K.; Shindell, D.; Worden, H.; Lamarque, J. F.; Young, P. J.; Stevenson, D.; Qu, Z.; de la Torre, M.; Bergmann, D.; Cameron-Smith, P.; Collins, W. J.; Doherty, R.; Dalsøren, S.; Faluvegi, G.; Folberth, G.; Horowitz, L. W.; Josse, B.; Lee, Y. H.; MacKenzie, I.; Myhre, G.; Nagashima, T.; Naik, V.; Plummer, D.; Rumbold, S.; Skeie, R.; Strode, S.; Sudo, K.; Szopa, S.; Voulgarakis, A.; Zeng, G.; Kulawik, S.; Worden, J.

    2012-09-01

    We use simultaneous observations of ozone and outgoing longwave radiation (OLR) from the Tropospheric Emission Spectrometer (TES) to evaluate ozone distributions and radiative forcing simulated by a suite of chemistry-climate models that participated in the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP). The ensemble mean of ACCMIP models show a persistent but modest tropospheric ozone low bias (5-20 ppb) in the Southern Hemisphere (SH) and modest high bias (5-10 ppb) in the Northern Hemisphere (NH) relative to TES for 2005-2010. These biases lead to substantial differences in ozone instantaneous radiative forcing between TES and the ACCMIP simulations. Using TES instantaneous radiative kernels (IRK), we show that the ACCMIP ensemble mean has a low bias in the SH tropics of up to 100 m W m-2 locally and a global low bias of 35 ± 44 m W m-2 relative to TES. Combining ACCMIP preindustrial ozone and the TES present-day ozone, we calculate an observationally constrained estimate of tropospheric ozone radiative forcing (RF) of 399 ± 70 m W m-2, which is about 7% higher than using the ACCMIP models alone but with the same standard deviation (Stevenson et al., 2012). In addition, we explore an alternate approach to constraining radiative forcing estimates by choosing a subset of models that best match TES ozone, which leads to an ozone RF of 369 ± 42 m W m-2. This estimate is closer to the ACCMIP ensemble mean RF but about a 40% reduction in standard deviation. These results point towards a profitable direction of combining observations and chemistry-climate model simulations to reduce uncertainty in ozone radiative forcing.

  15. Airborne measurement of ozone and precursors near Houston, Texas on June 11, 1997

    SciTech Connect

    Valente, R.J.; Shauck, M.; Zanin, G.; Pendleton, D.; Lambeth, B.; Price, J.; Rozacky, K.

    1998-12-31

    The advent of revised ambient air quality standards for ozone has rekindled interest in the formation and transport of ozone in urban and power plant plumes. The State of Texas, Baylor University, and the Tennessee Valley Authority are currently involved in a cooperative airborne air pollution monitoring program designed to study the formation and transport of ozone and precursors in Texas. A King Air model A90 aircraft has been outfitted with continuous instrumentation for ozone, NO{sub x}, NO, SO{sub 2}, hydrocarbons, light scattering, temperature, altitude, and position. This aircraft has logged 45 flights with over 200 hours of flight data for the 1997 field season. This work represents one of the first successful applications of an air pollution research aircraft for on-call use by a state regulatory authority. This paper presents results from a case study of ozone formation and transport in the Houston, Texas area on June 11, 1997. The case study documents the magnitude of an elevated ozone episode in the Houston area including a discussion of the role of transported versus locally produced ozone. Both vertical and horizontal variability of ozone and precursors are studied with special emphasis given to the implications of the measurements in light of the revised ambient air quality standard for ozone. The relationship between ozone formation and increased NO{sub x} and other precursors is also documented. Also discussed are some of the logistical challenges of an intensive program of this nature. Other objectives of the research and monitoring project are also mentioned including plans to use the Baylor King Air platform to study the transboundary pollutant transport at the US-Mexican border and interregional transport between Texas and other regions of the US.

  16. Ozone Bioindicator Gardens: an Educational Tool to Raise Awareness about Environmental Pollution and its Effects on Living Systems

    NASA Astrophysics Data System (ADS)

    Lapina, K.; Lombardozzi, D.

    2014-12-01

    High concentrations of ground-level ozone cause health problems in humans and a number of negative effects on plants, from reduced yield for major agricultural crops to reduced amounts of carbon stored in trees. The Denver Metro/Colorado Front Range is exceeding the National Ambient Air Quality Standard for ozone on a regular basis in summer and the efforts to reduce the ozone levels are hampered by the presence of diverse pollution sources and complex meteorology in the region. To raise public awareness of air quality in the Colorado Front Range and to educate all age groups about ground-level ozone, two ozone bioindicator gardens were planted in Boulder in Spring 2014. The gardens contain ozone-sensitive plants that develop a characteristic ozone injury when exposed to high levels of ozone. The ozone gardens are providing the general public with a real-life demonstration of the negative effects of ozone pollution through observable plant damage. Additionally, the gardens are useful in teaching students how to collect and analyze real-world scientific data.

  17. An Inter-Regional Comparison of Ozone Sensitivity to Reductions in Emissions in Central California

    NASA Astrophysics Data System (ADS)

    Soong, S.; Tanrikulu, S.; Tran, C.; Jia, Y.; Beaver, S.; Matsuoka, J.; Cordova, J.

    2011-12-01

    Emissions of ozone precursors NOx and VOC have declined significantly in central California over the past 60 years due to rigorous emission control programs, with 40 to 50 percent reductions achieved from 1990 to 2010 alone. Three major air basins, however, are still designated as nonattainment areas for the federal 8-hour ozone standard: the San Francisco Bay Area (SFBA), Sacramento area and the San Joaquin Valley (SJV). Historically, ozone response to reductions in emissions varied from region to region. While the maximum hourly ozone concentrations have declined significantly in all three air basins, the locations of maximum ozone shifted. Some exceedance areas came into compliance with the standard while new areas started exceeding the standard. Some areas did not significantly respond to reductions in emissions. To meet the current ozone standard, additional emission reductions are needed. Further emission reductions above and beyond the goal of meeting the current standard will be needed if the EPA lowers the current standard. In an effort to help planners and decision makers, we have been conducting a modeling study to better understand how ozone may respond to future emission reductions in the region. In this initial phase of the study, we used the WRF-CMAQ modeling system to simulate ozone for July 12-28, 2006, a representative high ozone period for all three air basins. With the selected high grid resolution and optimum model setup, the model performance for the base case simulation was exceptionally good. Statistical agreement with observations was better than most previously applied models in the region. We performed a number of sensitivity simulations by reducing anthropogenic VOC or NOx emissions separately or together 10-60 percent at 10 percent intervals uniformly across the board and prepared EKMA diagrams at observation stations. We found that a 60 percent reduction in VOC and NOx emissions reduced the maximum ozone by 20-30 percent in the

  18. Inactivation characteristics of ozone and electrolysis process for ballast water treatment using B. subtilis spores as a probe.

    PubMed

    Jung, Youmi; Yoon, Yeojoon; Hong, Eunkyung; Kwon, Minhwan; Kang, Joon-Wun

    2013-07-15

    Since ballast water affects the ocean ecosystem, the International Maritime Organization (IMO) sets a standard for ballast water management and might impose much tighter regulations in the future. The aim of this study is to evaluate the inactivation efficiency of ozonation, electrolysis, and an ozonation-electrolysis combined process, using B. subtilis spores. In seawater ozonation, HOBr is the key active substance for inactivation, because of rapid reactivity of ozone with Br(-) in seawater. In seawater electrolysis, it is also HOBr, but not HOCl, because of the rapid reaction of HOCl with Br(-), which has not been recognized carefully, even though many electrolysis technologies have been approved by the IMO. Inactivation pattern was different in ozonation and electrolysis, which has some limitations with the tailing or lag-phase, respectively. However, each deficiency can be overcome with a combined process, which is most effective as a sequential application of ozonation followed by electrolysis.

  19. Tentative critical levels of tropospheric ozone for agricultural crops in Japan

    NASA Astrophysics Data System (ADS)

    Yonekura, T.

    2010-12-01

    Ground level ozone concentrations have increased year by year in Japan. High ozone concentrations have been known to affect growth and yield of agricultural crops. In the US and Europe, much effort has been directed to establish regulatory policies such as secondary air quality standard and critical levels to protect vegetation against ozone. On the contrary, in Japan, there is a few data of agricultural crops sensitivity to ozone. Furthermore, there is no information about the ozone risk of agricultural crop loss by based on ozone index (e.g. AOT40, SUM06, W126)-crop response relationship, yet. The objects of our research are: (1) to screen sensitivity of ozone on 10 crops cultivated in urban area in Japan. (2) to establish critical levels of ozone for protecting agricultural crops based on ozone index-crop response relationship. The 10 Japanese agricultural crops such as Japanese rice, Hanegi (Welsh onion), Shungiku (Crown daisy), Saradana (Lettus), Hatsukadaikon (Radish), Kokabu (Small Turnip), Santosai (Chinese cabbage), Tasai (Spinach mustard), Komatsuna (Japanese mustard spinach) and Chingensai (Bok Choy), were fumigated to three levels of ozone (clean air (< 5 ppbv), ambient level of ozone, 1.5 times ambient ozone) in open-top chambers during 30 to 120 days. Those experiments were repeated five times during two growing season. Throughout the experimental period, the growth or yield were measured, and the relationship between growth (or yield) and ozone index was examined. As a result, the influences of ozone on growth or yield were different among 10 crops. Relatively good correlations of coefficients of determination (r2) for linear regressions to growth or yield were obtained with “8h means” and “AOT40” rather than “SUM00”, “SUM06” and “W126”. Critical level for 10 crops in terms of an AOT40 were 1.1 to 2.1 ppm h per month. The ozone sensitive crop in our study was sound to be 1.0 ppm h per month in AOT40.

  20. Ecosystem Effects of Ozone Pollution

    EPA Pesticide Factsheets

    Ground level ozone is absorbed by the leaves of plants, where it can reduce photosynthesis, damage leaves and slow growth. It can also make sensitive plants more susceptible to certain diseases, insects, harsh weather and other pollutants.

  1. Ozone - Current Air Quality Index

    MedlinePlus

    Local Air Quality Conditions Zip Code: State : My Current Location Forecast Current AQI AQI Loop More Maps AQI: Good (0 - ... September 2016, Busan, South Korea. More more announcements Air Quality Basics Air Quality Index | Ozone | Particle Pollution | Smoke ...

  2. In situ Mars ozone detector

    NASA Technical Reports Server (NTRS)

    Lindner, Bernhard Lee; Weinstock, Elliot M.

    1994-01-01

    We propose sending a balloon-borne UV photometer sensor package to measure atmospheric ozone on Mars, and this package could be a Discovery Program sensor candidate. Past measurements of ozone on Mars are highly uncertain, perhaps a factor of 3 or so uncertain, due primarily to interference and masking by cloud and dust. In-situ balloon measurements would avoid these problems, and would provide 'ground truth' which remote sensing techniques cannot. We have explored this approach to measure ozone abundance in the terrestrial stratosphere with a balloon-borne UV absorption photometer. Atmospheric pressures and temperatures and ozone concentrations near the surface of Mars are similar to those in the terrestrial stratosphere.

  3. Ozonation of cooling tower waters

    NASA Technical Reports Server (NTRS)

    Humphrey, M. F.; French, K. R.; Howe, R. D. (Inventor)

    1979-01-01

    Continuous ozone injection into water circulating between a cooling tower and heat exchanger with heavy scale deposits inhibits formation of further deposits, promotes flaking of existing deposits, inhibits chemical corrosion and controls algae and bacteria.

  4. Biological effects of ozone reduction

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The effects of increased UV radiation on the biosphere are described with ongoing research, and research areas that should be investigated. Some mention is also made of the potential climatic effects of ozone reduction on agriculture and the biosphere.

  5. A search For Artic ozone

    NASA Astrophysics Data System (ADS)

    Maggs, William Ward

    Four atmospheric scientists took off with their instruments for Greenland last week, where they will try to see if depletion of stratospheric ozone in the Arctic can be detected as it has been in Antarctica since 1985.Members of the scientific team include Susan Solomon and George Mount of the Aeronomy Laboratory at the National Atmospheric and Oceanic Administration (NOAA) in Boulder, Colo., and Ryan Sanders and Roger Jakoubec of the Cooperative Institute for Research in Environmental Science in Norman, Okla. These four participated in previous National Ozone Expedition (NOZE) investigations at McMurdo Station in Antarctica that helped document the ozone “hole,” decreases of up to 50% in ozone during the early austral spring in September and October of the last 2 years (1986-1987).

  6. Ozone (Environmental Health Student Portal)

    MedlinePlus

    ... Pollutants Natural Disasters Drinking Water Waterborne Diseases & Illnesses Water Cycle Water Treatment Videos Games Experiments For Teachers Home ... Pollutants Natural Disasters Drinking Water Waterborne Diseases & Illnesses Water Cycle Water Treatment Ozone The Basics A single atom ...

  7. Corona Discharge Influences Ozone Concentrations Near Rats

    SciTech Connect

    Goheen, Steven C.; Gaither, Kari A.; Anantatmula, Shantha M.; Mong, Gary M.; Sasser, Lyle B.; Lessor, Delbert L.

    2004-02-26

    Ozone is produced by corona discharge in air. Its production is enhanced near grounded water. Whether grounded animals behave like grounded water, producing more ozone was investigated. Rats were exposed to corona discharge in a plastic cage. The concentration of ozone in the gas phase was monitored. The ozone concentration exceeded ambient levels only in the presence of corona discharge and either rats or water. When water or rats were exposed to corona discharge, ozone levels were more than 10 times higher than controls. Ozone levels increased rapidly with applied voltage. There was also a correlation between the distance of the corona needle to the rats and the amount of ozone produced. As the distance increased, ozone production decreased. These results are discussed in relation to the potential exposure of mammals to ozone in the vicinity of corona discharge and electric fields.

  8. Method of sterilization using ozone

    NASA Technical Reports Server (NTRS)

    Murphy, Oliver J. (Inventor); Hitchens, G. Duncan (Inventor)

    2002-01-01

    Methods of using ozone have been developed which sterilize instruments and medical wastes, oxidize, organics found in wastewater, clean laundry, break down contaminants in soil into a form more readily digested by microbes, kill microorganisms present in food products, and destroy toxins present in food products. The preferred methods for killing microorganism and destroying toxins use pressurized, humidified, and concentrated ozone produced by an electrochemical cell.

  9. Ozone Treatment For Cooling Towers

    NASA Technical Reports Server (NTRS)

    Blackwelder, Rick; Baldwin, Leroy V.; Feeney, Ellen S.

    1990-01-01

    Report presents results of study of cooling tower in which water treated with ozone instead of usual chemical agents. Bacteria and scale reduced without pollution and at low cost. Operating and maintenance costs with treatment about 30 percent of those of treatment by other chemicals. Corrosion rates no greater than with other chemicals. Advantage of ozone, even though poisonous, quickly detected by smell in very low concentrations.

  10. Ozonation of Common Textile Auxiliaries

    NASA Astrophysics Data System (ADS)

    Iskender, Gulen; Arslan-Alaton, Idil; Koyunluoglu, Sebnem; Yilmaz, Zeynep; Germirli Babuna, Fatos

    2016-10-01

    The treatability of four different commonly applied textile auxiliary chemicals, namely two tannin formulations (Tannin 1: a condensation product of aryl sulphonate; Tannin 2: natural tannic acid) and two biocidal finishing agents (Biocide 1: 2,4,4’-trichloro-2’- hydroxydiphenyl ether; Biocide 2: a nonionic diphenyl alkane derivative) with ozone was investigated. Increasing the ozone dose yielded higher COD removals for the natural tannin. Optimum ozone doses of 485 and 662 mg/h were obtained at a pH of 3.5 for natural and synthetic tannin carrying textile bath discharges, respectively. When the reaction pH was increased from 3.5 to 7.0, a slight decrease in COD removal was observed for the natural tannin due to ozone selectivity towards its polyaromatic structure. The same increase in ozonation pH enhanced COD removals for the synthetic tannin as a result of enhanced ozone decomposition rendering free radical chain reactions dominant. Optimum ozone doses of 499 and 563 mg/h were established for Biocide 1 and 2, respectively. With the increase of ozonation, pH exhibited a positive influence on COD removals for both textile tannins. A substantial improvement in terms of TOC removals was observed as the reaction pH was increased from 3.5 to 7.0 for the synthetic tannin, and from 7 to 12 for both textile biocides. Higher AOX removals were evident at pH 7 than at pH 12 for Biocide 1 as a result of the higher selectivity of the dehalogenation reaction at neutral pH.

  11. Chlorine compounds and stratospheric ozone

    NASA Technical Reports Server (NTRS)

    Cicerone, R. J.; Walters, S.; Stolarski, R. S.

    1975-01-01

    A report by Cicerone et al. (1974) concerned with the potential size of the atmospheric perturbation produced by man-made chlorofluoromethanes is considered, giving attention to a number of errors made in the first investigation and their correction. However, the corrections do not significantly change the results reported. It had been found that chlorine oxides which arise from chlorofluoromethane usage will within 10 or 15 years provide a sink for stratospheric ozone which will dominate the natural sinks for ozone.

  12. The Use of Regulatory Air Quality Models to Develop Successful Ozone Attainment Strategies

    NASA Astrophysics Data System (ADS)

    Canty, T. P.; Salawitch, R. J.; Dickerson, R. R.; Ring, A.; Goldberg, D. L.; He, H.; Anderson, D. C.; Vinciguerra, T.

    2015-12-01

    The Environmental Protection Agency (EPA) recently proposed lowering the 8-hr ozone standard to between 65-70 ppb. Not all regions of the U.S. are in attainment of the current 75 ppb standard and it is expected that many regions currently in attainment will not meet the future, lower surface ozone standard. Ozone production is a nonlinear function of emissions, biological processes, and weather. Federal and state agencies rely on regulatory air quality models such as the Community Multi-Scale Air Quality (CMAQ) model and Comprehensive Air Quality Model with Extensions (CAMx) to test ozone precursor emission reduction strategies that will bring states into compliance with the National Ambient Air Quality Standards (NAAQS). We will describe various model scenarios that simulate how future limits on emission of ozone precursors (i.e. NOx and VOCs) from sources such as power plants and vehicles will affect air quality. These scenarios are currently being developed by states required to submit a State Implementation Plan to the EPA. Projections from these future case scenarios suggest that strategies intended to control local ozone may also bring upwind states into attainment of the new NAAQS. Ground based, aircraft, and satellite observations are used to ensure that air quality models accurately represent photochemical processes within the troposphere. We will highlight some of the improvements made to the CMAQ and CAMx model framework based on our analysis of NASA observations obtained by the OMI instrument on the Aura satellite and by the DISCOVER-AQ field campaign.

  13. Control strategy optimization for attainment and exposure mitigation: case study for ozone in Macon, Georgia.

    PubMed

    Cohan, Daniel S; Tian, Di; Hu, Yongtao; Russell, Armistead G

    2006-09-01

    Implementation of more stringent 8-hour ozone standards has led the U.S. Environmental Protection Agency to designate nonattainment status to 474 counties nationwide, many of which had never previously violated air quality standards. As states select emission control measures to achieve attainment in these regions, their choices pose significant implications to local economies and the health of their citizens. Considering a case study of one such nonattainment region, Macon, Georgia, we develop a menu of potential controls that could be implemented locally or in neighboring parts of the state. The control menu offers the potential to control about 20-35% of ozone precursor emissions in most Georgia regions, but marginal costs increase rapidly beyond 15-20%. We link high-order ozone sensitivities with the control menu to identify cost-optimized strategies for achieving attainment and for alternative goals such as reducing spatially averaged or population-weighted ozone concentrations. Strategies targeted toward attainment of Macon ozone would prioritize local reductions of nitrogen oxides, whereas controls in the more densely populated Atlanta region are shown to be more effective for reducing statewide potential population exposure to ozone. A U.S. EPA-sanctioned approach for demonstrating ozone attainment with photochemical models is shown to be highly dependent on the choice of a baseline period and may not foster optimal strategies for assuring attainment and protecting human health.

  14. Sensitivity analysis of ozone formation and transport for a Central California air pollution episode

    SciTech Connect

    Jin, Ling; Tonse, Shaheen; Cohan, Daniel S.; Mao, Xiaoling; Harley, Robert A.; Brown, Nancy J.

    2009-05-15

    CMAQ-HDDM is used to determine spatial and temporal variations in ozone limiting reagents and local vs upwind source contributions for an air pollution episode in Central California. We developed a first- and second- order sensitivity analysis approach with the Decoupled Direct Method to examine spatial and temporal variations of ozone-limiting reagents and the importance of local vs upwind emission sources in the San Joaquin Valley of central California for a five-day ozone episode (29th July-3rd Aug, 2000). Despite considerable spatial variations, nitrogen oxides (NO{sub x}) emission reductions are overall more effective than volatile organic compound (VOC) control for attaining the 8-hr ozone standard in this region for this episode, in contrast to the VOC control that works better for attaining the prior 1-hr ozone standard. Inter-basin source contributions of NO{sub x} emissions are limited to the northern part of the SJV, while anthropogenic VOC (AVOC) emissions, especially those emitted at night, influence ozone formation in the SJV further downwind. Among model input parameters studied here, uncertainties in emissions of NO{sub x} and AVOC, and the rate coefficient of the OH + NO{sub 2} termination reaction, have the greatest effect on first-order ozone responses to changes in NO{sub x} emissions. Uncertainties in biogenic VOC emissions only have a modest effect because they are generally not collocated with anthropogenic sources in this region.

  15. Ozone Conference II: Abstract Proceedings

    SciTech Connect

    1999-11-01

    Ozone Conference II: Pre- and Post-Harvest Applications Two Years After Gras, was held September 27-28, 1999 in Tulare, California. This conference, sponsored by EPRI's Agricultural Technology Alliance and Southern California Edison's AgTAC facility, was coordinated and organized by the on-site ATA-AgTAC Regional Center. Approximately 175 people attended the day-and-a-half conference at AgTAC. During the Conference twenty-two presentations were given on ozone food processing and agricultural applications. Included in the presentations were topics on: (1) Ozone fumigation; (2) Ozone generation techniques; (3) System and design applications; (4) Prewater treatment requirements; (5) Poultry water reuse; (6) Soil treatments with ozone gas; and (7) Post-harvest aqueous and gaseous ozone research results. A live videoconference between Tulare and Washington, D.C. was held to discuss the regulators' view from inside the beltway. Attendees participated in two Roundtable Question and Answer sessions and visited fifteen exhibits and demonstrations. The attendees included university and governmental researchers, regulators, consultants and industry experts, technology developers and providers, and corporate and individual end-users. This report is comprised of the Abstracts of each presentation, biographical sketches for each speaker and a registration/attendees list.

  16. The 2002 Antarctic Ozone Hole

    NASA Technical Reports Server (NTRS)

    Newman, P. A.; Nash, E. R.; Douglass, A. R.; Kawa, S. R.

    2003-01-01

    Since 1979, the ozone hole has grown from near zero size to over 24 Million km2. This area is most strongly controlled by levels of inorganic chlorine and bromine oncentrations. In addition, dynamical variations modulate the size of the ozone hole by either cooling or warming the polar vortex collar region. We will review the size observations, the size trends, and the interannual variability of the size. Using a simple trajectory model, we will demonstrate the sensitivity of the ozone hole to dynamical forcing, and we will use these observations to discuss the size of the ozone hole during the 2002 Austral spring. We will further show how the Cly decreases in the stratosphere will cause the ozone hole to decrease by 1-1.5% per year. We will also show results from a 3-D chemical transport model (CTM) that has been continuously run since 1999. These CTM results directly show how strong dynamics acts to reduce the size of the ozone hole.

  17. New dynamic NNORSY ozone profile climatology

    NASA Astrophysics Data System (ADS)

    Kaifel, A. K.; Felder, M.; Declercq, C.; Lambert, J.-C.

    2012-01-01

    Climatological ozone profile data are widely used as a-priori information for total ozone using DOAS type retrievals as well as for ozone profile retrieval using optimal estimation, for data assimilation or evaluation of 3-D chemistry-transport models and a lot of other applications in atmospheric sciences and remote sensing. For most applications it is important that the climatology represents not only long term mean values but also the links between ozone and dynamic input parameters. These dynamic input parameters should be easily accessible from auxiliary datasets or easily measureable, and obviously should have a high correlation with ozone. For ozone profile these parameters are mainly total ozone column and temperature profile data. This was the outcome of a user consultation carried out in the framework of developing a new, dynamic ozone profile climatology. The new ozone profile climatology is based on the Neural Network Ozone Retrieval System (NNORSY) widely used for ozone profile retrieval from UV and IR satellite sounder data. NNORSY allows implicit modelling of any non-linear correspondence between input parameters (predictors) and ozone profile target vector. This paper presents the approach, setup and validation of a new family of ozone profile climatologies with static as well as dynamic input parameters (total ozone and temperature profile). The neural network training relies on ozone profile measurement data of well known quality provided by ground based (ozonesondes) and satellite based (SAGE II, HALOE, and POAM-III) measurements over the years 1995-2007. In total, four different combinations (modes) for input parameters (date, geolocation, total ozone column and temperature profile) are available. The geophysical validation spans from pole to pole using independent ozonesonde, lidar and satellite data (ACE-FTS, AURA-MLS) for individual and time series comparisons as well as for analysing the vertical and meridian structure of different modes of

  18. Error analysis of Dobson spectrophotometer measurements of the total ozone content

    NASA Technical Reports Server (NTRS)

    Holland, A. C.; Thomas, R. W. L.

    1975-01-01

    A study of techniques for measuring atmospheric ozone is reported. This study represents the second phase of a program designed to improve techniques for the measurement of atmospheric ozone. This phase of the program studied the sensitivity of Dobson direct sun measurements and the ozone amounts inferred from those measurements to variation in the atmospheric temperature profile. The study used the plane - parallel Monte-Carlo model developed and tested under the initial phase of this program, and a series of standard model atmospheres.

  19. Scientific assessment of ozone depletion: 1991

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Over the past few years, there have been highly significant advances in the understanding of the impact of human activities on the Earth's stratospheric ozone layer and the influence of changes in chemical composition of the radiative balance of the climate system. Specifically, since the last international scientific review (1989), there have been five major advances: (1) global ozone decreases; (2) polar ozone; (3) ozone and industrial halocarbons; (4) ozone and climate relations; and (5) ozone depletion potentials (ODP's) and global warming potentials (GWP's). These topics and others are discussed.

  20. Impact of downward-mixing ozone on surface ozone accumulation in southern Taiwan.

    PubMed

    Lin, Ching-Ho

    2008-04-01

    The ozone that initially presents in the previous day's afternoon mixing layer can remain in the nighttime atmosphere and then be carried over to the next morning. Finally, this ozone can be brought to the ground by downward mixing as mixing depth increases during the daytime, thereby increasing surface ozone concentrations. Variation of ozone concentration during each of these periods is investigated in this work. First, ozone concentrations existing in the daily early morning atmosphere at the altitude range of the daily maximum mixing depth (residual ozone concentrations) were measured using tethered ozonesondes on 52 experimental days during 2004-2005 in southern Taiwan. Daily downward-mixing ozone concentrations were calculated by a box model coupling the measured daily residual ozone concentrations and daily mixing depth variations. The ozone concentrations upwind in the previous day's afternoon mixing layer were estimated by the combination of back air trajectory analysis and known previous day's surface ozone distributions. Additionally, the relationship between daily downward-mixing ozone concentration and daily photochemically produced ozone concentration was examined. The latter was calculated by removing the former from daily surface maximum ozone concentration. The measured daily residual ozone concentrations distributed at 12-74 parts per billion (ppb) with an average of 42 +/- 17 ppb are well correlated with the previous upwind ozone concentration (R2 = 0.54-0.65). Approximately 60% of the previous upwind ozone was estimated to be carried over to the next morning and became the observed residual ozone. The daily downward-mixing ozone contributes 48 +/- 18% of the daily surface maximum ozone concentration, indicating that the downward-mixing ozone is as important as daily photochemically produced ozone to daily surface maximum ozone accumulation. The daily downward-mixing ozone is poorly correlated with the daily photochemically produced ozone and