Science.gov

Sample records for 8 hour ozone

  1. 40 CFR 51.908 - What modeling and attainment demonstration requirements apply for purposes of the 8-hour ozone...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... demonstration requirements apply for purposes of the 8-hour ozone NAAQS? 51.908 Section 51.908 Protection of..., AND SUBMITTAL OF IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient... purposes of the 8-hour ozone NAAQS? (a) What is the attainment demonstration requirement for an...

  2. 40 CFR 51.908 - What modeling and attainment demonstration requirements apply for purposes of the 8-hour ozone...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... demonstration requirements apply for purposes of the 8-hour ozone NAAQS? 51.908 Section 51.908 Protection of..., AND SUBMITTAL OF IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient... purposes of the 8-hour ozone NAAQS? (a) What is the attainment demonstration requirement for an...

  3. 40 CFR 51.908 - What modeling and attainment demonstration requirements apply for purposes of the 8-hour ozone...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... demonstration requirements apply for purposes of the 8-hour ozone NAAQS? 51.908 Section 51.908 Protection of..., AND SUBMITTAL OF IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient... purposes of the 8-hour ozone NAAQS? (a) What is the attainment demonstration requirement for an...

  4. 40 CFR 51.908 - What modeling and attainment demonstration requirements apply for purposes of the 8-hour ozone...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... demonstration requirements apply for purposes of the 8-hour ozone NAAQS? 51.908 Section 51.908 Protection of..., AND SUBMITTAL OF IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient... purposes of the 8-hour ozone NAAQS? (a) What is the attainment demonstration requirement for an...

  5. 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... Standard § 51.914 What new source review requirements apply for 8-hour ozone nonattainment areas? The requirements for new source review for the 8-hour ozone standard are located in § 51.165 of this part....

  6. 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... Standard § 51.914 What new source review requirements apply for 8-hour ozone nonattainment areas? The requirements for new source review for the 8-hour ozone standard are located in § 51.165 of this part....

  7. 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... Standard § 51.914 What new source review requirements apply for 8-hour ozone nonattainment areas? The requirements for new source review for the 8-hour ozone standard are located in § 51.165 of this part....

  8. 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... Standard § 51.914 What new source review requirements apply for 8-hour ozone nonattainment areas? The requirements for new source review for the 8-hour ozone standard are located in § 51.165 of this part....

  9. 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... Standard § 51.914 What new source review requirements apply for 8-hour ozone nonattainment areas? The requirements for new source review for the 8-hour ozone standard are located in § 51.165 of this part....

  10. 40 CFR 52.387 - Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-hour ozone and PM2.5 NAAQS. 52.387 Section 52.387 Protection of Environment ENVIRONMENTAL PROTECTION... § 52.387 Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS. On March 13, 2007, the State...)(D)(i) interstate transport requirements of the Clean Air Act for the 1997 8-hour ozone and...

  11. 40 CFR 52.387 - Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...-hour ozone and PM2.5 NAAQS. 52.387 Section 52.387 Protection of Environment ENVIRONMENTAL PROTECTION... § 52.387 Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS. On March 13, 2007, the State...)(D)(i) interstate transport requirements of the Clean Air Act for the 1997 8-hour ozone and...

  12. 40 CFR 52.387 - Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-hour ozone and PM2.5 NAAQS. 52.387 Section 52.387 Protection of Environment ENVIRONMENTAL PROTECTION... § 52.387 Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS. On March 13, 2007, the State...)(D)(i) interstate transport requirements of the Clean Air Act for the 1997 8-hour ozone and...

  13. 40 CFR 52.387 - Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...-hour ozone and PM2.5 NAAQS. 52.387 Section 52.387 Protection of Environment ENVIRONMENTAL PROTECTION... § 52.387 Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS. On March 13, 2007, the State...)(D)(i) interstate transport requirements of the Clean Air Act for the 1997 8-hour ozone and...

  14. 40 CFR 52.387 - Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-hour ozone and PM2.5 NAAQS. 52.387 Section 52.387 Protection of Environment ENVIRONMENTAL PROTECTION... § 52.387 Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS. On March 13, 2007, the State...)(D)(i) interstate transport requirements of the Clean Air Act for the 1997 8-hour ozone and...

  15. 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...

  16. 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...

  17. 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...

  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 51.916 - 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...

  20. 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...

  1. 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...

  2. 40 CFR 52.1393 - Interstate Transport Declaration for the 1997 8-hour ozone and PM2.5 NAAQS.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... the 1997 8-hour ozone and PM2.5 NAAQS. 52.1393 Section 52.1393 Protection of Environment ENVIRONMENTAL... (CONTINUED) Montana § 52.1393 Interstate Transport Declaration for the 1997 8-hour ozone and PM2.5 NAAQS. The... Section 110(a)(2)(D)(i) for the 8-hour ozone and PM2.5 NAAQS promulgated in July 1997. The...

  3. 40 CFR 52.1393 - Interstate Transport Declaration for the 1997 8-hour ozone and PM2.5 NAAQS.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... the 1997 8-hour ozone and PM2.5 NAAQS. 52.1393 Section 52.1393 Protection of Environment ENVIRONMENTAL... (CONTINUED) Montana § 52.1393 Interstate Transport Declaration for the 1997 8-hour ozone and PM2.5 NAAQS. The... Section 110(a)(2)(D)(i) for the 8-hour ozone and PM2.5 NAAQS promulgated in July 1997. The...

  4. 40 CFR 52.1393 - Interstate Transport Declaration for the 1997 8-hour ozone and PM2.5 NAAQS.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... the 1997 8-hour ozone and PM2.5 NAAQS. 52.1393 Section 52.1393 Protection of Environment ENVIRONMENTAL... (CONTINUED) Montana § 52.1393 Interstate Transport Declaration for the 1997 8-hour ozone and PM2.5 NAAQS. The... Section 110(a)(2)(D)(i) for the 8-hour ozone and PM2.5 NAAQS promulgated in July 1997. The...

  5. 40 CFR 52.1393 - Interstate Transport Declaration for the 1997 8-hour ozone and PM2.5 NAAQS.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... the 1997 8-hour ozone and PM2.5 NAAQS. 52.1393 Section 52.1393 Protection of Environment ENVIRONMENTAL... (CONTINUED) Montana § 52.1393 Interstate Transport Declaration for the 1997 8-hour ozone and PM2.5 NAAQS. The... Section 110(a)(2)(D)(i) for the 8-hour ozone and PM2.5 NAAQS promulgated in July 1997. The...

  6. 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

    ... Part 81 Air pollution control, National parks, Wilderness areas. Authority: 42 U.S.C. 7401 et seq... Baltimore Area) did not attain the 1997 8-hour ozone national ambient air quality standard (NAAQS) by its... Agency, Region III, 1650 Arch Street, Philadelphia, Pennsylvania 19103. D. Hand Delivery: At...

  7. 40 CFR 52.2499 - Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 4 2011-07-01 2011-07-01 false Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS. 52.2499 Section 52.2499 Protection of Environment ENVIRONMENTAL PROTECTION...) Washington § 52.2499 Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS. On January 17, 2007,...

  8. 40 CFR 52.97 - Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 3 2013-07-01 2013-07-01 false Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS. 52.97 Section 52.97 Protection of Environment ENVIRONMENTAL PROTECTION....97 Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS. On February 7, 2008, the...

  9. 40 CFR 52.97 - Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 3 2012-07-01 2012-07-01 false Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS. 52.97 Section 52.97 Protection of Environment ENVIRONMENTAL PROTECTION....97 Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS. On February 7, 2008, the...

  10. 40 CFR 52.97 - Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 3 2011-07-01 2011-07-01 false Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS. 52.97 Section 52.97 Protection of Environment ENVIRONMENTAL PROTECTION....97 Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS. On February 7, 2008, the...

  11. 40 CFR 52.2499 - Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 5 2012-07-01 2012-07-01 false Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS. 52.2499 Section 52.2499 Protection of Environment ENVIRONMENTAL PROTECTION...) Washington § 52.2499 Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS. On January 17, 2007,...

  12. 40 CFR 52.97 - Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 3 2010-07-01 2010-07-01 false Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS. 52.97 Section 52.97 Protection of Environment ENVIRONMENTAL PROTECTION....97 Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS. On February 7, 2008, the...

  13. 40 CFR 52.2499 - Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 4 2010-07-01 2010-07-01 false Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS. 52.2499 Section 52.2499 Protection of Environment ENVIRONMENTAL PROTECTION...) Washington § 52.2499 Interstate Transport for the 1997 8-hour ozone and PM2.5 NAAQS. On January 17, 2007,...

  14. 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

    ... ozone NAAQS are codified in 40 CFR part 81. ... 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...

  15. 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

    ... with respect to the 1997 ozone NAAQS are codified in 40 CFR part 81. ... 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...

  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

    ... with respect to the 1997 ozone NAAQS are codified in 40 CFR part 81. ... 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...

  17. 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...

  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, 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...

  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, 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...

  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, 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...

  1. 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...

  2. 40 CFR 51.917 - What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... designation for the Las Vegas, NV, 8-hour ozone nonattainment area? 51.917 Section 51.917 Protection of... Air Quality Standard § 51.917 What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area? The Las Vegas, NV, 8-hour ozone nonattainment area (designated on September...

  3. 40 CFR 51.917 - What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... designation for the Las Vegas, NV, 8-hour ozone nonattainment area? 51.917 Section 51.917 Protection of... Air Quality Standard § 51.917 What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area? The Las Vegas, NV, 8-hour ozone nonattainment area (designated on September...

  4. 40 CFR 51.917 - What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... designation for the Las Vegas, NV, 8-hour ozone nonattainment area? 51.917 Section 51.917 Protection of... Air Quality Standard § 51.917 What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area? The Las Vegas, NV, 8-hour ozone nonattainment area (designated on September...

  5. 40 CFR 51.917 - What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... designation for the Las Vegas, NV, 8-hour ozone nonattainment area? 51.917 Section 51.917 Protection of... Air Quality Standard § 51.917 What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area? The Las Vegas, NV, 8-hour ozone nonattainment area (designated on September...

  6. 40 CFR 51.917 - What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... designation for the Las Vegas, NV, 8-hour ozone nonattainment area? 51.917 Section 51.917 Protection of... Air Quality Standard § 51.917 What is the effective date of designation for the Las Vegas, NV, 8-hour ozone nonattainment area? The Las Vegas, NV, 8-hour ozone nonattainment area (designated on September...

  7. 78 FR 65877 - Approval and Promulgation of Implementation Plans; Atlanta, Georgia 1997 8-Hour Ozone...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-04

    ... noted, EPA has already approved Rule (jjj). See 64 FR 67491 and 74 FR 62249. This rulemaking does not... Georgia's ROP plan for the 1-hour ozone NAAQS for the Atlanta Area on April 26, 1999. See 64 FR 20196. \\3..., Paulding, and Rockdale. See 56 FR 56694, November 6, 1991. \\4\\ Seven additional ``ring'' counties...

  8. 78 FR 32135 - Approval and Promulgation of Implementation Plans; Atlanta, Georgia 1997 8-Hour Ozone...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-29

    ... the 1-hour ozone NAAQS for the Atlanta Area on April 26, 1999. See 64 FR 20196. \\3\\ The 13-County... Area's original attainment date was June 15, 2007. See 69 FR 23951, April 30, 2004. The Atlanta Area.... See 73 FR 12013, March 6, 2008. When an area is reclassified, a new attainment date for...

  9. 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

    ..., e-mail address, and telephone and fax numbers. Questions concerning the August 24, 2010 (75 FR 51960... holding the public hearing was published in the Federal Register on August 24, 2010 (75 FR 51960), and is... AGENCY 40 CFR Part 51 RIN 2060-AP30 Rule To Implement the 1997 8-Hour Ozone National Ambient Air...

  10. 77 FR 28423 - Final Rule To Implement the 1997 8-Hour Ozone National Ambient Air Quality Standard...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-14

    ... based.'' The process for making these adjustments is described at 69 FR 23863 et seq. (April 30, 2004... rulemaking (74 FR 2936). \\1\\ 74 FR 2936, January 16, 2009. III. This Action A. Classification of 8-Hour Ozone... Determination, pursuant to 40 CFR 51.918, 70 FR 71702). The obligation to complete and submit those...

  11. 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

    ... for a 1-year extension, the Philadelphia Area's 4th highest daily 8-hour monitored ozone value during...), as required by 40 CFR 51.907(a). The highest-reading monitoring site had a 4th high value for 2009 of... Control Measure'' proposed July 22, 2010 (75 FR 42672); and (2) The maximum 4th highest daily...

  12. 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

    .... Louis (MO-IL) metropolitan nonattainment area on February 28, 2011 (76 FR 10815). A detailed discussion... that the area has attained the NAAQS during the 2008- 2010 monitoring period. On March 27, 2008 (73 FR... addressed this 2008 revised standard and proposed to set the primary 8-hour ozone standard within the...

  13. 76 FR 2859 - Approval and Promulgation of Air Quality Implementation Plans; Virginia; Adoption of 8-hour Ozone...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-18

    ... of 8-hour Ozone Standard and Related Reference Conditions, and Update of Appendices AGENCY... reference conditions, and updating the list of appendices under ``Documents Incorporated by Reference.'' In... Reference Conditions, and Update of Appendices,'' that is located in the ``Rules and Regulations''...

  14. 40 CFR 51.908 - What modeling and attainment demonstration requirements apply for purposes of the 8-hour ozone...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... classified as moderate or higher under subpart 2 pursuant to § 51.903? An area classified as moderate or... area subject only to subpart 1 in accordance with § 51.902(b)? An area subject to § 51.902(b) shall be... demonstration requirements apply for purposes of the 8-hour ozone NAAQS? 51.908 Section 51.908 Protection...

  15. 76 FR 10815 - Approval and Promulgation of Determination of Attainment for the 1997 8-Hour Ozone Standard...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-28

    ... 12898 (59 FR 7629, February 16, 1994). In addition, this proposed 8-hour ozone clean NAAQS data... that the area has attained the NAAQS during the 2008-2010 monitoring period. On March 27, 2008 (73 FR... by the Office of Management and Budget under Executive Order 12866 (58 FR 51735, October 4,...

  16. 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

    ...).) 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 Air....S. Environmental Protection Agency, Region III, 1650 Arch Street, Philadelphia, Pennsylvania...

  17. 40 CFR 52.1989 - Interstate Transport for the 1997 8-hour ozone NAAQS and 1997 PM2.5 NAAQS.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 4 2011-07-01 2011-07-01 false Interstate Transport for the 1997 8-hour ozone NAAQS and 1997 PM2.5 NAAQS. 52.1989 Section 52.1989 Protection of Environment ENVIRONMENTAL... (CONTINUED) Oregon § 52.1989 Interstate Transport for the 1997 8-hour ozone NAAQS and 1997 PM2.5 NAAQS....

  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 Section 51.918 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS... 8-hour Ozone National Ambient Air Quality Standard § 51.918 Can any SIP planning requirements...

  19. Trends analyses of 30 years of ambient 8 hour ozone and precursor monitoring data in the South Central U.S.: progress and challenges.

    PubMed

    Sather, Mark E; Cavender, Kevin

    2016-07-13

    In the last 30 years ambient ozone concentrations have notably decreased in the South Central U.S. Yet, current ambient ozone concentrations measured over the past three years 2013-2015 in this area of the U.S. are not meeting the U.S. 2015 8 hour ozone standard of 70 parts per billion (ppb). This paper provides an update on long-term trends analyses of ambient 8 hour ozone and ozone precursor monitoring data collected over the past 30 years (1986-2015) in four South Central U.S. cities, following up on two previously published reviews of 20 and 25 year trends for these cities. All four cities have benefitted from national ozone precursor controls put in place during the 1990s and 2000s involving cleaner vehicles (vehicle fleet turnover/replacement over time), cleaner fuels, cleaner gasoline and diesel engines, and improved inspection/maintenance programs for existing vehicles. Additional ozone precursor emission controls specific to each city are detailed in this paper. The controls have resulted in impressive ambient ozone and ambient ozone precursor concentration reductions in the four South Central U.S. cities over the past 30 years, including 31-70% ambient nitrogen oxides (NOx) concentration declines from historical peaks to the present, 43-72% volatile organic compound (VOC) concentration declines from historical peaks to the present, a related 45-76% VOC reactivity decline for a subset of VOC species from historical peaks to the present, and an 18-38 ppb reduction in city 8 hour ozone design value concentrations. A new challenge for each of the four South Central U.S. cities will be meeting the U.S. 2015 8 hour ozone standard of 70 ppb. PMID:27282109

  20. 78 FR 34965 - Approval and Promulgation of Air Quality Implementation Plans; Ohio; 1997 8-Hour Ozone...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-11

    ... accepted during the Regional Office ] normal hours of operation, and special arrangements should be made... second comment period. Any parties interested in commenting on this action should do so at this...

  1. 75 FR 47746 - Determination of Nonattainment and Reclassification of the Dallas/Fort Worth 1997 8-hour Ozone...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-09

    .... It is not usually emitted directly into the air, but at ground level is created by a chemical reaction between volatile organic compounds (VOCs) and oxides of nitrogen (NO X ) in the presence of... is more protective than the previous 1-hour ozone standard (62 FR 38855) that was established by...

  2. 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

    ... designation (for most areas the effective date of the 1997 8-hour designation was June 15, 2004). 40 CFR 51... (69 FR 23951, April 30, 2004). The rule further provides that an area remains subject to these applicable requirements until the area attains the 1997 8-hour NAAQS. 40 CFR 51.905(b). Additionally,...

  3. 75 FR 8331 - Adequacy Status of the Cincinnati, Ohio/Indiana Submitted 8-Hour Ozone Redesignation and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-24

    ... submitted SIP budgets in our July 1, 2004, preamble starting at 69 FR 40038, and we used the information in... (NOx) as precursors to ozone in the Ohio and Indiana portions of the Cincinnati-Hamilton,...

  4. 76 FR 2829 - Approval and Promulgation of Air Quality Implementation Plans; Virginia; Adoption of 8-hour Ozone...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-18

    ... NAAQS for ozone on March 27, 2008 (73 FR 16436). II. Summary of SIP Revision On September 27, 2010, the... Budget under Executive Order 12866 (58 FR 51735, October 4, 1993); Does not impose an information...); Does not have Federalism implications as specified in Executive Order 13132 (64 FR 43255, August...

  5. 78 FR 34965 - Approval and Promulgation of Air Quality Implementation Plans; Ohio; Lima 1997 8-Hour Ozone...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-11

    ... arrangements should be made for deliveries of boxed information. The Regional Office official hours of business... second comment period. Any parties interested in commenting on this action should do so at this...

  6. Eastern Texas Air Quality Forecasting System to Support TexAQS-II and 8-hour Ozone Modeling

    NASA Astrophysics Data System (ADS)

    Byun, D. W.

    2005-12-01

    The main objective of the Second Texas Air Quality Study (TexAQS-II) for 2005 and 2006 is to understand emissions and processes associated with the formation and transport of ozone and regional haze in Texas. The target research area is the more populated eastern half of the state, roughly from Interstate 35 eastward. Accurate meteorological and photochemical modeling efforts are essential to support this study and further enhance modeling efforts for establishing the State Implementation Plan (SIP) by Texas Commission on Environmental Quality (TCEQ). An air quality forecasting (AQF) system for Eastern Texas has been developed to provide these data and to further facilitate retrospective simulations to allow for model improvement and increased understanding of ozone episodes and emissions. We perform two-day air quality forecasting simulations with the 12-km Eastern Texas regional domain, and the 4-km Houston-Galveston area (HGA) domain utilizing a 48-CPU Beowulf Linux computer system. The dynamic boundary conditions are provided by the 36-km resolution conterminous US (CONUS) domain CMAQ simulations. Initial meteorological conditions are provided by the daily ETA forecast results. The results of individual runs are stored and made available to researchers and state and local officials via internet to study the patterns of air quality and its relationship to weather conditions and emissions. The data during the pre- and post-processing stages are in tens of gigabytes and must be managed efficiently during both the actual real-time and the subsequent computation periods. The nature of these forecasts and the time at which the initial data is available necessitates that models be executed within tight deadlines. A set of complex operational scripts is used to allow automatic operation of the data download, sequencing processors, performing graphical analysis, building database archives, and presenting on the web.

  7. A Procedure for Inter-Comparing the Skill of Regional-Scale Air Quality Model Simulations of Daily Maximum 8-Hour Ozone Concentrations

    EPA Science Inventory

    An operational model evaluation procedure is described to quantitatively assess the relative skill among several regionalscale air quality models simulating various percentiles of the cumulative frequency distribution of observed daily maximum 8-h ozone concentrations. Bootstrap ...

  8. 40 CFR 51.906 - Redesignation to nonattainment following initial designations for the 8-hour NAAQS.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... OF IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient Air Quality... subsequently redesignated to nonattainment for the 8-hour ozone NAAQS, any absolute, fixed date applicable...

  9. 40 CFR 51.906 - Redesignation to nonattainment following initial designations for the 8-hour NAAQS.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... OF IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient Air Quality... subsequently redesignated to nonattainment for the 8-hour ozone NAAQS, any absolute, fixed date applicable...

  10. 40 CFR 51.906 - Redesignation to nonattainment following initial designations for the 8-hour NAAQS.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... OF IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient Air Quality... subsequently redesignated to nonattainment for the 8-hour ozone NAAQS, any absolute, fixed date applicable...

  11. 40 CFR 51.906 - Redesignation to nonattainment following initial designations for the 8-hour NAAQS.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... OF IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient Air Quality... subsequently redesignated to nonattainment for the 8-hour ozone NAAQS, any absolute, fixed date applicable...

  12. 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...

  13. 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...

  14. 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...

  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, 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...

  16. 40 CFR 51.913 - How do the section 182(f) NOX exemption provisions apply for the 8-hour NAAQS?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient Air Quality Standard § 51.913... designated nonattainment for the 8-hour ozone NAAQS and for any area in a section 184 ozone transport region...) A section 182(f) NOX exemption granted for the 1-hour ozone standard does not relieve the area...

  17. 40 CFR 51.915 - What emissions inventory requirements apply under the 8-hour NAAQS?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... PLANS Provisions for Implementation of 8-hour Ozone National Ambient Air Quality Standard § 51.915 What... emissions inventories for these areas, the ozone-relevant data element requirements under 40 CFR part...

  18. 40 CFR 51.915 - What emissions inventory requirements apply under the 8-hour NAAQS?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... PLANS Provisions for Implementation of 8-hour Ozone National Ambient Air Quality Standard § 51.915 What... emissions inventories for these areas, the ozone-relevant data element requirements under 40 CFR part...

  19. 40 CFR 51.915 - What emissions inventory requirements apply under the 8-hour NAAQS?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... PLANS Provisions for Implementation of 8-hour Ozone National Ambient Air Quality Standard § 51.915 What... emissions inventories for these areas, the ozone-relevant data element requirements under 40 CFR part...

  20. 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

    ....'' 57 FR 13498 (April 16, 1992). ARB used its mobile source emissions model EMFAC2002 to generate the on... of Proposed Actions On July 14, 2009 at 74 FR 33933, EPA proposed to approve in part and disapprove...-hour ozone standard). 69 FR 20550 (April 15, 2004). Although we established a new 8-hour ozone...

  1. 77 FR 75386 - Approval and Promulgation of Air Quality Implementation Plans; Virginia; Fredericksburg 8-Hour...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-20

    ... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION...; Fredericksburg 8-Hour Ozone Maintenance Area Revision to Approved Motor Vehicle Emissions Budgets AGENCY: Environmental Protection Agency (EPA). ] ACTION: Final rule; correcting amendment. SUMMARY: This...

  2. 77 FR 65490 - Approval and Promulgation of Air Quality Implementation Plans; Virginia; Fredericksburg 8-Hour...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-29

    ... ambient air quality standard (NAAQS) for ozone. This action is being taken under the Clean Air Act (CAA... requirements of Section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272...; Fredericksburg 8-Hour Ozone Maintenance Area Revision to Approved Motor Vehicle Emissions Budgets...

  3. 40 CFR 51.915 - What emissions inventory requirements apply under the 8-hour NAAQS?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... PLANS Provisions for Implementation of 8-hour Ozone National Ambient Air Quality Standard § 51.915 What... emissions inventory requirement in section 172(c)(3) of the Act shall apply, and an emission inventory SIP... emissions inventories for these areas, the ozone-relevant data element requirements under 40 CFR part...

  4. Pulmonary Responses in Healthy Young Adults Exposed to Low Concentration of Ozone for 6.6 Hours with Mild Exercise

    EPA Science Inventory

    Rational: Recent studies have shown small but significant decreases in lung function following a prolonged exposure (6.6 hour) of healthy young adults to levels of ozone (0.08 ppm) near the current 8 hour standard. It is unclear, however, if such effects may be extended to concen...

  5. Integrated assessment modeling of atmospheric pollutants in the Southern Appalachian Mountains. Part I: hourly and seasonal ozone.

    PubMed

    Boylan, James W; Odman, Mehmet T; Wilkinson, James G; Russell, Armistead G; Doty, Kevin G; Norris, William B; McNider, Richard T

    2005-07-01

    Recently, a comprehensive air quality modeling system was developed as part of the Southern Appalachians Mountains Initiative (SAMI) with the ability to simulate meteorology, emissions, ozone, size- and composition-resolved particulate matter, and pollutant deposition fluxes. As part of SAMI, the RAMS/EMS-95/URM-1ATM modeling system was used to evaluate potential emission control strategies to reduce atmospheric pollutant levels at Class I areas located in the Southern Appalachians Mountains. This article discusses the details of the ozone model performance and the methodology that was used to scale discrete episodic pollutant levels to seasonal and annual averages. The daily mean normalized bias and error for 1-hr and 8-hr ozone were within U.S. Environment Protection Agency guidance criteria for urban-scale modeling. The model typically showed a systematic overestimation for low ozone levels and an underestimation for high levels. Because SAMI was primarily interested in simulating the growing season ozone levels in Class I areas, daily and seasonal cumulative ozone exposure, as characterized by the W126 index, were also evaluated. The daily ozone W126 performance was not as good as the hourly ozone performance; however, the seasonal ozone W126 scaled up from daily values was within 17% of the observations at two typical Class I areas of the SAMI region. The overall ozone performance of the model was deemed acceptable for the purposes of SAMI's assessment. PMID:16111143

  6. 77 FR 36163 - Determinations of Failure To Attain the One-Hour Ozone Standard by 2007, Current Attainment of...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-18

    ... determining that the area previously failed to attain the one-hour ozone National Ambient Air Quality Standard... ozone monitoring data for 2008-2010. Quality-assured ozone monitoring data in the Air Quality System for... area previously failed to attain the one-hour ozone National Ambient Air Quality Standard (NAAQS)...

  7. 40 CFR 51.915 - What emissions inventory requirements apply under the 8-hour NAAQS?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... emissions inventories for these areas, the ozone-relevant data element requirements under 40 CFR part 51... nonattainment area subject only to title I, part D, subpart 1 of the Act in accordance with § 51.902(b), the... apply under the 8-hour NAAQS? 51.915 Section 51.915 Protection of Environment ENVIRONMENTAL...

  8. 40 CFR 51.913 - How do the section 182(f) NOX exemption provisions apply for the 8-hour NAAQS?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... provisions apply for the 8-hour NAAQS? 51.913 Section 51.913 Protection of Environment ENVIRONMENTAL... IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient Air Quality Standard § 51.913... petition the Administrator for an exemption from NOX obligations under section 182(f) for any...

  9. 40 CFR 51.913 - How do the section 182(f) NOX exemption provisions apply for the 8-hour NAAQS?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... provisions apply for the 8-hour NAAQS? 51.913 Section 51.913 Protection of Environment ENVIRONMENTAL... IMPLEMENTATION PLANS Provisions for Implementation of 8-hour Ozone National Ambient Air Quality Standard § 51.913... petition the Administrator for an exemption from NOX obligations under section 182(f) for any...

  10. 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

    ...-hour standards are codified in 40 CFR part 81. (c) EPA's authority under paragraph (b) of this section... 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...

  11. 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

    ...-hour standards are codified in 40 CFR part 81. ... 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...

  12. 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

    ...-hour standards are codified in 40 CFR part 81. ... 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...

  13. 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

    ...-hour standards are codified in 40 CFR part 81. (c) EPA's authority under paragraph (b) of this section... 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...

  14. 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

    ...-hour standards are codified in 40 CFR part 81. ... 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...

  15. 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

    2013-03-01

    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

  16. Differential Absorption Lidar to Measure Sub-Hourly Variation of Tropospheric Ozone Profiles

    NASA Technical Reports Server (NTRS)

    Kuang, Shi; Burris, John F.; Newchurch, Michael J.; Johnson, Steve; Long, Stephanie

    2009-01-01

    A tropospheric ozone Differential Absorption Lidar (DIAL) system, developed jointly by the University of Alabama at Huntsville and NASA, is making regular observations of ozone vertical distributions between 1 and 8 km with two receivers under both daytime and nighttime conditions using lasers at 285 and 291 nm. This paper describes the lidar system and analysis technique with some measurement examples. An iterative aerosol correction procedure reduces the retrieval error arising from differential aerosol backscatter in the lower troposphere. Lidar observations with coincident ozonesonde flights demonstrate that the retrieval accuracy ranges from better than 10% below 4 km to better than 20% below 8 km with 750-m vertical resolution and 10-min temporal integration

  17. 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

    2013-03-01

    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

  18. 40 CFR 51.907 - For an area that fails to attain the 8-hour NAAQS by its attainment date, how does EPA interpret...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... for Implementation of 8-hour Ozone National Ambient Air Quality Standard § 51.907 For an area that... 40 Protection of Environment 2 2012-07-01 2012-07-01 false For an area that fails to attain the 8... the CAA? 51.907 Section 51.907 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY...

  19. 40 CFR 51.907 - For an area that fails to attain the 8-hour NAAQS by its attainment date, how does EPA interpret...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... for Implementation of 8-hour Ozone National Ambient Air Quality Standard § 51.907 For an area that... 40 Protection of Environment 2 2014-07-01 2014-07-01 false For an area that fails to attain the 8... the CAA? 51.907 Section 51.907 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY...

  20. Ozone, Electrostatic Precipitators, and Particle Number Concentrations: Correlations Observed in a Real Office during Working Hours.

    PubMed

    Xiang, Jianbang; Weschler, Charles J; Mo, Jinhan; Day, Drew; Zhang, Junfeng; Zhang, Yinping

    2016-09-20

    This study investigates the impacts of outdoor and indoor ozone concentrations, ESP operation and occupancy on particle number concentrations within a modern office in Changsha, China. The office's one-pass air handling system contains a mini-bag filter (MERV 12) followed by an electrostatic precipitator (ESP) and high efficiency particulate air (HEPA) filter. Over a five-week period the system was operated either without the ESP (Stage 1, first-third week) or with the ESP (Stage 2, fourth and fifth week). Ozone and particle number concentrations were measured on working days. During both stages, indoor ozone and particle number concentrations tracked the outdoor ozone concentration. When operating, the ESP produced approximately 29 mg h(-1) of ozone, increasing supply air ozone by 15 ppb and steady-state indoor ozone by about 3 ppb. Occupancy tended to decrease indoor ozone and increase particle levels. During occupancy, indoor particle levels were low (∼2600 particle/cm(3)) when the supply air ozone level was less than 18 ppb. Above this threshold, the supply air ozone concentration and indoor particle number concentration were linearly related, and ESP operation increased the average indoor particle level by about 22 000 particles/cm(3). The implications for worker exposure to both ozone and particles are discussed. PMID:27571436

  1. Ozone, Electrostatic Precipitators, and Particle Number Concentrations: Correlations Observed in a Real Office during Working Hours.

    PubMed

    Xiang, Jianbang; Weschler, Charles J; Mo, Jinhan; Day, Drew; Zhang, Junfeng; Zhang, Yinping

    2016-09-20

    This study investigates the impacts of outdoor and indoor ozone concentrations, ESP operation and occupancy on particle number concentrations within a modern office in Changsha, China. The office's one-pass air handling system contains a mini-bag filter (MERV 12) followed by an electrostatic precipitator (ESP) and high efficiency particulate air (HEPA) filter. Over a five-week period the system was operated either without the ESP (Stage 1, first-third week) or with the ESP (Stage 2, fourth and fifth week). Ozone and particle number concentrations were measured on working days. During both stages, indoor ozone and particle number concentrations tracked the outdoor ozone concentration. When operating, the ESP produced approximately 29 mg h(-1) of ozone, increasing supply air ozone by 15 ppb and steady-state indoor ozone by about 3 ppb. Occupancy tended to decrease indoor ozone and increase particle levels. During occupancy, indoor particle levels were low (∼2600 particle/cm(3)) when the supply air ozone level was less than 18 ppb. Above this threshold, the supply air ozone concentration and indoor particle number concentration were linearly related, and ESP operation increased the average indoor particle level by about 22 000 particles/cm(3). The implications for worker exposure to both ozone and particles are discussed.

  2. Adaptation by older individuals repeatedly exposed to 0. 45 parts per million ozone for two hours

    SciTech Connect

    Bedi, J.F.; Horvath, S.M.; Drechsler-Parks, D.M.

    1989-02-01

    To test for an increased reaction to ozone (O3) in older individuals following an initial exposure, and to test for adaptation and its duration, we exposed 10 men and 6 women (60-89 years old) in an environmental chamber to filtered air and 3 consecutive days of O3 exposure (0.45 ppm), followed by a fourth O3 exposure day after a two day hiatus. Subjects alternated 20-min exercise (minute ventilation = 27 L) and rest periods for 2 hours during each exposure. Subjects rated from one to five, 16 possible respiratory/exercise symptoms prior to and following the exposure. Pulmonary function tests were performed before, and during each rest period and following the exposure. Metabolic measurements were obtained during each exercise period. No significant changes in any symptom question occurred, in spite of a threefold increase in the total number of reported symptoms during O3 exposure. Small but significant pre-to-post decrements on the first and second O3 days in forced vital capacity (FVC-111 and 104 mL), forced expiratory volume in 1 (FEV1-171 and 164 mL) and 3 seconds (FEV3-185 and 172 mL) occurred without concomitant changes in any flow parameter of the forced expiratory maneuver. No differences in the group mean response in FVC, FEV1 or FEV3 on the third or fourth day of O3 exposure and the filtered air exposure were found. The observed changes were due to significant physiological changes in eight of the subjects. Unlike young subjects, no evidence of an increased pulmonary function response to a second consecutive O3 exposure was observed.

  3. New classification scheme for ozone monitoring stations based on frequency distribution of hourly data.

    PubMed

    Tapia, O; Escudero, M; Lozano, Á; Anzano, J; Mantilla, E

    2016-02-15

    According to European Union (EU) legislation, ozone (O3) monitoring sites can be classified regarding their location (rural background, rural, suburban, urban) or based on the presence of emission sources (background, traffic, industrial). There have been attempts to improve these classifications aiming to reduce their ambiguity and subjectivity, but although scientifically sound, they lack the simplicity needed for operational purposes. We present a simple methodology for classifying O3 stations based on the characteristics of frequency distribution curves which are indicative of the actual impact of combustion sources emitting NO that consumes O3 via titration. Four classes are identified using 1998-2012 hourly data from 72 stations widely distributed in mainland Spain and the Balearic Islands. Types 1 and 2 present unimodal bell-shaped distribution with very low amount of data near zero reflecting a limited influence of combustion sources while Type 4 has a primary mode close to zero, showing the impact of combustion sources, and a minor mode for higher concentrations. Type 3 stations present bimodal distributions with the main mode in the higher levels. We propose a quantitative metric based on the Gini index with the objective of reproducing this classification and finding empirical ranges potentially useful for future classifications. The analysis of the correspondence with the EUROAIRNET classes for the 72 stations reveals that the proposed scheme is only dependent on the impact of combustion sources and not on climatic or orographic aspects. It is demonstrated that this classification is robust since in 87% of the occasions the classification obtained for individual years coincide with the global classification obtained for the 1998-2012 period. Finally, case studies showing the applicability of the new classification scheme for assessing the impact on O3 of a station relocation and performing a critical evaluation of an air quality monitoring network are

  4. New classification scheme for ozone monitoring stations based on frequency distribution of hourly data.

    PubMed

    Tapia, O; Escudero, M; Lozano, Á; Anzano, J; Mantilla, E

    2016-02-15

    According to European Union (EU) legislation, ozone (O3) monitoring sites can be classified regarding their location (rural background, rural, suburban, urban) or based on the presence of emission sources (background, traffic, industrial). There have been attempts to improve these classifications aiming to reduce their ambiguity and subjectivity, but although scientifically sound, they lack the simplicity needed for operational purposes. We present a simple methodology for classifying O3 stations based on the characteristics of frequency distribution curves which are indicative of the actual impact of combustion sources emitting NO that consumes O3 via titration. Four classes are identified using 1998-2012 hourly data from 72 stations widely distributed in mainland Spain and the Balearic Islands. Types 1 and 2 present unimodal bell-shaped distribution with very low amount of data near zero reflecting a limited influence of combustion sources while Type 4 has a primary mode close to zero, showing the impact of combustion sources, and a minor mode for higher concentrations. Type 3 stations present bimodal distributions with the main mode in the higher levels. We propose a quantitative metric based on the Gini index with the objective of reproducing this classification and finding empirical ranges potentially useful for future classifications. The analysis of the correspondence with the EUROAIRNET classes for the 72 stations reveals that the proposed scheme is only dependent on the impact of combustion sources and not on climatic or orographic aspects. It is demonstrated that this classification is robust since in 87% of the occasions the classification obtained for individual years coincide with the global classification obtained for the 1998-2012 period. Finally, case studies showing the applicability of the new classification scheme for assessing the impact on O3 of a station relocation and performing a critical evaluation of an air quality monitoring network are

  5. 40 CFR 51.906 - Redesignation to nonattainment following initial designations for the 8-hour NAAQS.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... following initial designations for the 8-hour NAAQS. 51.906 Section 51.906 Protection of Environment... Standard § 51.906 Redesignation to nonattainment following initial designations for the 8-hour NAAQS. For any area that is initially designated attainment or unclassifiable for the 8-hour NAAQS and that...

  6. The quantity of nursing care on wards working 8- and 12-hour shifts.

    PubMed

    Reid, N; Robinson, G; Todd, C

    1993-10-01

    Interest in 12-hour nursing shifts has been renewed in response to demands for improved cost-effectiveness in the NHS, but the effects of this shift on the delivery of patient care have been unclear. This paper describes the results of a repeated-measures study of 10 wards, using activity analysis to describe patterns of care under an 8-hour compared to a 12-hour shift system. Significant reductions in the amount of direct patient care were found under the 12-hour shift, with corresponding increases in unofficial work-breaks. It is suggested that these findings, which were consistent over all study wards and throughout the whole 12-hour day, demonstrate a "pacing" effect by nurses who face 12 hours on duty. Such a detrimental effect should be a major consideration when coming to any decision to implement a 12-hour shift.

  7. A New Differential Absorption Lidar to Measure Sub-Hourly Fluctuation of Tropospheric Ozone Profiles in the Baltimore - Washington D.C. Region

    NASA Technical Reports Server (NTRS)

    Sullivan, J. T.; McGee, T. J.; Sumnicht, G. K.; Twigg, L. W.; Hoff, R. M.

    2014-01-01

    Tropospheric ozone profiles have been retrieved from the new ground based National Aeronautics and Space Administration (NASA) Goddard Space Flight Center TROPospheric OZone DIfferential Absorption Lidar (GSFC TROPOZ DIAL) in Greenbelt, MD (38.99 N, 76.84 W, 57 meters ASL) from 400 m to 12 km AGL. Current atmospheric satellite instruments cannot peer through the optically thick stratospheric ozone layer to remotely sense boundary layer tropospheric ozone. In order to monitor this lower ozone more effectively, the Tropospheric Ozone Lidar Network (TOLNet) has been developed, which currently consists of five stations across the US. The GSFC TROPOZ DIAL is based on the Differential Absorption Lidar (DIAL) technique, which currently detects two wavelengths, 289 and 299 nm. Ozone is absorbed more strongly at 289 nm than at 299 nm. The DIAL technique exploits this difference between the returned backscatter signals to obtain the ozone number density as a function of altitude. The transmitted wavelengths are generated by focusing the output of a quadrupled Nd:YAG laser beam (266 nm) into a pair of Raman cells, filled with high pressure hydrogen and deuterium. Stimulated Raman Scattering (SRS) within the focus generates a significant fraction of the pump energy at the first Stokes shift. With the knowledge of the ozone absorption coefficient at these two wavelengths, the range resolved number density can be derived. An interesting atmospheric case study involving the Stratospheric-Tropospheric Exchange (STE) of ozone is shown to emphasize the regional importance of this instrument as well as assessing the validation and calibration of data. The retrieval yields an uncertainty of 16-19 percent from 0-1.5 km, 10-18 percent from 1.5-3 km, and 11-25 percent from 3 km to 12 km. There are currently surface ozone measurements hourly and ozonesonde launches occasionally, but this system will be the first to make routine tropospheric ozone profile measurements in the Baltimore

  8. A new differential absorption lidar to measure sub-hourly fluctuation of tropospheric ozone profiles in the Baltimore-Washington DC region

    NASA Astrophysics Data System (ADS)

    Sullivan, J. T.; McGee, T. J.; Sumnicht, G. K.; Twigg, L. W.; Hoff, R. M.

    2014-04-01

    Tropospheric ozone profiles have been retrieved from the new ground based National Aeronautics and Space Administration (NASA) Goddard Space Flight Center TROPospheric OZone DIfferential Absorption Lidar (GSFC TROPOZ DIAL) in Greenbelt, MD (38.99° N, 76.84° W, 57 m a.s.l.) from 400 m to 12 km a.g.l. Current atmospheric satellite instruments cannot peer through the optically thick stratospheric ozone layer to remotely sense boundary layer tropospheric ozone. In order to monitor this lower ozone more effectively, the Tropospheric Ozone Lidar Network (TOLNet) has been developed, which currently consists of five stations across the US. The GSFC TROPOZ DIAL is based on the Differential Absorption Lidar (DIAL) technique, which currently detects two wavelengths, 289 and 299 nm. Ozone is absorbed more strongly at 289 nm than at 299 nm. The DIAL technique exploits this difference between the returned backscatter signals to obtain the ozone number density as a function of altitude. The transmitted wavelengths are generated by focusing the output of a quadrupled Nd:YAG laser beam (266 nm) into a pair of Raman cells, filled with high pressure hydrogen and deuterium. Stimulated Raman Scattering (SRS) within the focus generates a significant fraction of the pump energy at the first Stokes shift. With the knowledge of the ozone absorption coefficient at these two wavelengths, the range resolved number density can be derived. An interesting atmospheric case study involving the Stratospheric-Tropospheric Exchange (STE) of ozone is shown to emphasize the regional importance of this instrument as well as assessing the validation and calibration of data. The retrieval yields an uncertainty of 16-19% from 0-1.5 km, 10-18% from 1.5-3 km, and 11-25% from 3 km to 12 km. There are currently surface ozone measurements hourly and ozonesonde launches occasionally, but this system will be the first to make routine tropospheric ozone profile measurements in the Baltimore-Washington DC area.

  9. Respiratory response of humans exposed to low levels of ozone for 6. 6 hours

    SciTech Connect

    McDonnell, W.F.; Kehrl, H.R.; Abdul-Salaam, S.; Ives, P.J.; Folinsbee, L.J.

    1991-05-01

    Recent evidence suggests that prolonged exposures of exercising men to 0.08 ppm ozone (O3) result in significant decrements in lung function, induction of respiratory symptoms, and increases in nonspecific airway reactivity. The purpose of the study was to confirm or refute these findings by exposing 38 healthy young men to 0.08 ppm (O3) for 6.6 h. During exposure, subjects performed exercise for a total of 5 h, which required a minute ventilation of 40 l/min. Significant (O3)-induced decrements were observed for forced vital capacity (FVC, -0.25 1), forced expiratory volume in 1 s (FEV(sub 1.0), -0.35 l), and mean expiratory flow rate between 25% and 75% of FVC (FEF(sub 25-75), -0.57 l/s), and significant increases were observed in airway reactivity (35%), specific airway resistance (0.77 cm H2O/s), and respiratory symptoms. These results essentially confirm previous findings. A large range in individual responses was noted (e.g., percentage change in FEV(sub 1.0): 4% increase to 38% decrease). Responses also appeared to be nonlinear in time under these experimental conditions.

  10. A mobile differential absorption lidar to measure sub-hourly fluctuation of tropospheric ozone profiles in the Baltimore-Washington, D.C. region

    NASA Astrophysics Data System (ADS)

    Sullivan, J. T.; McGee, T. J.; Sumnicht, G. K.; Twigg, L. W.; Hoff, R. M.

    2014-10-01

    Tropospheric ozone profiles have been retrieved from the new ground-based National Aeronautics and Space Administration (NASA) Goddard Space Flight Center TROPospheric OZone DIfferential Absorption Lidar (GSFC TROPOZ DIAL) in Greenbelt, MD (38.99° N, 76.84° W, 57 m a.s.l.), from 400 m to 12 km a.g.l. Current atmospheric satellite instruments cannot peer through the optically thick stratospheric ozone layer to remotely sense boundary layer tropospheric ozone. In order to monitor this lower ozone more effectively, the Tropospheric Ozone Lidar Network (TOLNet) has been developed, which currently consists of five stations across the US. The GSFC TROPOZ DIAL is based on the DIAL technique, which currently detects two wavelengths, 289 and 299 nm, with multiple receivers. The transmitted wavelengths are generated by focusing the output of a quadrupled Nd:YAG laser beam (266 nm) into a pair of Raman cells, filled with high-pressure hydrogen and deuterium, using helium as buffer gas. With the knowledge of the ozone absorption coefficient at these two wavelengths, the range-resolved number density can be derived. An interesting atmospheric case study involving the stratospheric-tropospheric exchange (STE) of ozone is shown, to emphasize the regional importance of this instrument as well as to assess the validation and calibration of data. There was a low amount of aerosol aloft, and an iterative aerosol correction has been performed on the retrieved data, which resulted in less than a 3 ppb correction to the final ozone concentration. The retrieval yields an uncertainty of 16-19% from 0 to 1.5 km, 10-18% from 1.5 to 3 km, and 11-25% from 3 to 12 km according to the relevant aerosol concentration aloft. There are currently surface ozone measurements hourly and ozonesonde launches occasionally, but this system will be the first to make routine tropospheric ozone profile measurements in the Baltimore-Washington, D.C. area.

  11. 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 ...

  12. Sleep, sleepiness, and neurobehavioral performance while on watch in a simulated 4 hours on/8 hours off maritime watch system.

    PubMed

    van Leeuwen, Wessel M A; Kircher, Albert; Dahlgren, Anna; Lützhöft, Margareta; Barnett, Mike; Kecklund, Göran; Åkerstedt, Torbjörn

    2013-11-01

    Seafarer sleepiness jeopardizes safety at sea and has been documented as a direct or contributing factor in many maritime accidents. This study investigates sleep, sleepiness, and neurobehavioral performance in a simulated 4 h on/8 h off watch system as well as the effects of a single free watch disturbance, simulating a condition of overtime work, resulting in 16 h of work in a row and a missed sleep opportunity. Thirty bridge officers (age 30 ± 6 yrs; 29 men) participated in bridge simulator trials on an identical 1-wk voyage in the North Sea and English Channel. The three watch teams started respectively with the 00-04, the 04-08, and the 08-12 watches. Participants rated their sleepiness every hour (Karolinska Sleepiness Scale [KSS]) and carried out a 5-min psychomotor vigilance test (PVT) test at the start and end of every watch. Polysomnography (PSG) was recorded during 6 watches in the first and the second half of the week. KSS was higher during the first (mean ± SD: 4.0 ± 0.2) compared with the second (3.3 ± 0.2) watch of the day (p < 0.001). In addition, it increased with hours on watch (p < 0.001), peaking at the end of watch (4.1 ± 0.2). The free watch disturbance increased KSS profoundly (p < 0.001): from 4.2 ± 0.2 to 6.5 ± 0.3. PVT reaction times were slower during the first (290 ± 6 ms) compared with the second (280 ± 6 ms) watch of the day (p < 0.001) as well as at the end of the watch (289 ± 6 ms) compared with the start (281 ± 6 ms; p = 0.001). The free watch disturbance increased reaction times (p < 0.001) from 283 ± 5 to 306 ± 7 ms. Similar effects were observed for PVT lapses. One third of all participants slept during at least one of the PSG watches. Sleep on watch was most abundant in the team working 00-04 and it increased following the free watch disturbance. This study reveals that-within a 4 h on/8 h off shift system-subjective and

  13. 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 ...

  14. A 4.8 hour periodicity in the spectra of Cyg X-3

    NASA Technical Reports Server (NTRS)

    Becker, R. H.; Robinson-Saba, J. L.; Boldt, E. A.; Holt, S. S.; Pravdo, S. H.; Serlemitsos, P. J.; Swank, J. H.

    1978-01-01

    The X-ray spectra from three observations of the X-ray binary Cyg X-3 by the cosmic X-ray spectroscopy experiment on OSO can be represented by power-law continua with strong iron line emission. Comparisons of spectra taken within the same observation at various phases of the 4.8 hour period reveal a relative excess of low energy X-ray emission near zero phase (i.e. the minimum) of the 4.8 hour modulation. In addition, the centroid of the line emission is observed to vary in phase with the 4.8 hour cycle. The possibility of persistent thermal X-ray emission from material surrounding the binary system is introduced in an effort to account for the observed effects.

  15. 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

    ... Ambient Air Quality Standard § 51.905 How do areas transition from the 1-hour NAAQS to the 8-hour NAAQS...)(3)(iii) of this section. 40 CFR part 81, subpart C identifies the boundaries of areas and the area... obligations approved into the SIP pursuant to 40 CFR 51.121 and 51.122 may be modified by the State only...

  16. 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

    ... Ambient Air Quality Standard § 51.905 How do areas transition from the 1-hour NAAQS to the 8-hour NAAQS...)(3)(iii) of this section. 40 CFR part 81, subpart C identifies the boundaries of areas and the area... obligations approved into the SIP pursuant to 40 CFR 51.121 and 51.122 may be modified by the State only...

  17. 75 FR 80340 - Approval and Promulgation of Implementation Plans; New Jersey; 8-Hour Ozone Control Measures

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-12-22

    ... consists of two new rules, Subchapter 26, ``Prevention of Air Pollution From Adhesives, Sealants, Adhesive Primers and Sealant Primers,'' and Subchapter 34, ``TBAC Emissions Reporting,'' (TBAC means tertiary butyl acetate or t-butyl acetate) and revisions to Subchapter 23, ``Prevention of Air Pollution...

  18. 75 FR 9781 - Determination of Nonattainment and Reclassification of the Atlanta, Georgia, 8-Hour Ozone...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-04

    ... standard, was approved by EPA on March 6, 2008 (73 FR 12013). However, EPA inadvertently excluded Hall... this action. Statutory and Executive Order Reviews Under Executive Order 12866 (58 FR 51735, October 4... Use'' (66 FR 28355, May 22, 2001). This action merely corrects an inadvertent error of omission in...

  19. 78 FR 45188 - Agency Information Collection Activities; Proposed Collection; Comment Request; 8-Hour Ozone...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-26

    ... Protection Agency, T.W. Alexander Drive, Research Triangle Park, NC 27711; telephone number: (919) 541-2363...., Monday through Friday, excluding legal holidays. The telephone number for the Reading Room is 202-566... information, including the validity of the methodology and assumptions used; (iii) enhance the...

  20. 78 FR 47572 - Disapproval of State Implementation Plan; Infrastructure Requirements for the 1997 8-Hour Ozone...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-06

    ... restricted by statute. Certain other material, such as copyrighted material, is not placed on the Internet and will be publicly available only in hard copy form. Publicly available docket materials are..., section 110(a)(2)(E)(ii), is described in detail in our proposal of May 31, 2013 (78 FR 32613). The...

  1. 78 FR 32613 - Disapproval of State Implementation Plan; Infrastructure Requirements for the 1997 8-Hour Ozone...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-31

    ... 0.12 parts per million (ppm) to 0.08 ppm (62 FR 38856). By statute, SIPs meeting the requirements of..., 2007, which was determined to be complete on March 27, 2008 (73 FR 16205), and another dated December 22, 2009. On May 19, 2011 (76 FR 28934), EPA published a notice of proposed rulemaking (NPR) for...

  2. 78 FR 32222 - Approval and Promulgation of Implementation Plans; Atlanta, Georgia 1997 8-Hour Ozone...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-29

    ... 73 FR 16436. The current action, however, is being taken to address requirements under the earlier..., Gwinnett, Hall, Henry, Newton, Paulding, Rockdale, Spalding and Walton Counties in Georgia. EPA is...

  3. 78 FR 44439 - Approval and Promulgation of Implementation Plans: Atlanta, Georgia 1997 8-Hour Ozone...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-24

    ... institute a second comment period on this action. DATES: The direct final rule published at 78 FR 32135 on... May 29, 2013 (78 FR 32135), EPA published a direct final rulemaking to approve Georgia's October 21... action, also published on May 29, 2013 (78 FR 32222). EPA will not institute a second comment period...

  4. 75 FR 42672 - Approval and Promulgation of Implementation Plans; New Jersey; 8-hour Ozone Control Measures

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-07-22

    ... conditionally approved. See 74 FR 22837 (May 15, 2009). If EPA approves this proposed SIP revision, the RACT... Subchapter 24 occurred on January 25, 2006 (71 FR 4045). EPA had previously approved Subchapter 24 provisions... FR 2938 (January 19, 2010). In this proposed rule, based upon reconsideration of the primary...

  5. 75 FR 26225 - Adequacy Status of the Chicago, Illinois Area Submitted 8-Hour Ozone Redesignation and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-11

    ... budgets in our July 1, 2004, preamble starting at 69 FR 40038, and we used the information in these... Plans for Transportation Conformity Purposes AGENCY: Environmental Protection Agency (EPA). ACTION... conformity determinations. Illinois submitted a redesignation request and maintenance plan for the...

  6. 78 FR 34903 - Approval and Promulgation of Air Quality Implementation Plans; Ohio; 1997 8-Hour Ozone...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-11

    ... section 176(c) of the CAA. See the official release of the MOVES2010 emissions model (75 FR 9411-9414) for... source emissions for criteria pollutants, including precursors. Transportation plans and projects... highway emissions. EPA announced the release of MOVES2010 on March 2, 2010 (75 FR 9411). Use of the...

  7. Pulmonary function and symptom responses after 6. 6-hour exposure to 0. 12 ppm ozone with moderate exercise

    SciTech Connect

    Folinsbee, L.J.; McDonnell, W.F.; Horstman, D.H.

    1988-01-01

    Episodes occasionally occur when ambient ozone (O/sub 3/) levels remain at or near 0.12 ppm for more than 6 h. Small decrements in lung function have been reported following 2-h exposures to 0.12 ppm O/sub 3/. For short exposures to higher O/sub 3/ concentrations, lung function decrements are a function of exposure duration. Thus, we investigated the hypothesis that prolonged exposure to 0.12 ppm O/sub 3/ would result in progressively larger changes in respiratory function and symptoms over time. Ten nonsmoking males were exposed once to clean air and once to 0.12 ppm O/sub 3/ for 6.6 h. Exposures consisted of six 50-min exercise periods, each followed by 10-min rest and measurement; a 35-min lunch period followed by the third exercise period. Exercise ventilation averaged approximately 40 L/min. Forced expiratory and inspiratory spirometry and respiratory symptoms were measured prior to exposure and after each exercise. Airway reactivity to methacholine was determined after each exposure. After correcting for the air exposures, FEV 1.0 was found to decrease linearly during the O/sub 3/ exposure and was decreased by an average of 13.0 percent at the end of exposure. Decreases in FVC and FEF24-75% were also linear and averaged 8.3 and 17.4 percent, respectively, at the end of exposure. On forced inspiratory tests, the FIVC and FIV05 were decreased 12.6 and 20.7 percent, respectively. Increases in the symptom ratings of cough and pain on deep inspiration were observed with O/sub 3/ exposure but not with clean air. Airway reactivity to methacholine was approximately doubled following O/sub 3/ exposure.

  8. 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

    ... 8-hour ozone implementation rule, published on November 29, 2005 (70 FR 71612) (Phase 2 Rule... of the 2008 ozone NAAQS. \\2\\ See 73 FR 16436; March 27, 2008. For a detailed explanation of the... to address the requirements of the 1997 8-hour ozone standard: On July 17, 2008 (73 FR 41068),...

  9. 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

    ... National Ambient Air Quality Standard § 51.905 How do areas transition from the 1-hour NAAQS to the 1997 8... NAAQS maintenance area, the State may request that obligations under the applicable requirements of § 51.... Control obligations approved into the SIP pursuant to 40 CFR 51.121 and 51.122 may be modified by...

  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, 2013 CFR

    2013-07-01

    ... National Ambient Air Quality Standard § 51.905 How do areas transition from the 1-hour NAAQS to the 1997 8... requirement to submit a maintenance plan for purposes of paragraph (a)(3)(iii) of this section. 40 CFR part 81.... Control obligations approved into the SIP pursuant to 40 CFR 51.121 and 51.122 may be modified by...

  11. Ozone concentration and pulmonary response relationships for 6. 6-hour exposures with five hours of moderate exercise to 0. 08, 0. 10, and 0. 12 ppm

    SciTech Connect

    Horstman, D.H.; Folinsbee, L.J.; Ives, P.J.; Abdul-Salaam, S.; McDonnell, W.F. )

    1990-11-01

    The magnitudes of pulmonary responses we previously observed (1) following 6.6-h exposures to 0.12 ppm ozone (O3) suggested that responses would also occur with similar exposures at lower O3 concentrations. The objective of this study was to determine the extent of pulmonary function decrements, respiratory discomfort, and increased airway reactivity to methacholine induced by exposure to O3 below 0.12 ppm. Separate 6.6-h chamber exposures to 0.00, 0.08, 0.10, and 0.12 ppm O3 included six 50-min periods of moderate exercise (VE approximately equal to 39 L/min, HR approximately equal to 115 bpm, and VO2 approximately equal to 1.5 L/min). Each exercise period was followed by 10 min of rest. A 35-min lunch break was included midway through the exposure. Although not intended as an exact simulation, the overall duration, intensity, and metabolic requirements of the exercise performed were representative of a day of moderate to heavy work or play. Preexposure FEV1 averaged 4.39 L, and essentially no change (+0.03 L) occurred with exposure to 0.00 ppm O3. Significant decreases (p less than 0.01) of -0.31, -0.30, and -0.54 L were observed with exposures to 0.08, 0.10, and 0.12 ppm, respectively. The provocative dose of methacholine required to increase airway resistance by 100% (PD100) was 58 cumulative inhalation units (CIU) following exposure to 0.00 ppm and was significantly reduced (p less than 0.01) to 37 CIU at 0.08, 31 CIU at 0.10, and 26 CIU at 0.12 ppm O3; reductions in PD100 are considered indicative of increases in nonspecific airway responsiveness.

  12. Ozone-concentration and pulmonary-response relationships for 6. 6-hour exposures with five hours of moderate exercise to 0. 08, 0. 10, and 0. 12 ppm

    SciTech Connect

    Horstman, D.H.; Folinsbee, L.J.; Ives, P.J.; Salaam, S.A.; McDonnell, W.F.

    1990-01-01

    The magnitudes of pulmonary responses the authors previously observed (1) following 6.6-h exposure to 0.12 ppm ozone (O{sub 3}) suggested that responses would also occur with similar exposures at lower O{sub 3} concentrations. The objective of the study was to determine the extent of pulmonary function decrements, respiratory discomfort, and increased airway reactivity to methacholine induced by exposure to O{sub 3} below 0.12 ppm. Separate 6.6-h chamber exposures to 0.00, 0.08, 0.10, and 0.12 ppm O3 included six 50-min periods of moderate exercise (VE = 39 L/min, HR = 115 bpm, and VO2 = 1.5 L/min). Each exercise period was followed by 10 min of rest. A 35-min lunch break was included midway through the exposure. Although not intended as an exact simulation, the overall duration, intensity, and metabolic requirements of the exercise performed were representative of a day of moderate to heavy work or play. Preexposure FEV, averaged 4.39 L, and essentially no change (+0.03 L) occurred with exposure to 0.00 ppm O{sub 3}. Significant decreases (p<0.01) of -0.31, -0.30, and -0.54 L were observed with exposures to 0.08, 0.10, and 0.12 ppm, respectively. The study concludes that exposure to O{sub 3} at levels often found in ambient air while engaged in activity representative of a typical day of moderate to heavy work or play induced clinically meaningful pulmonary responses.

  13. 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 ...

  14. The Version 8.6 SBUV Ozone Data Record: An Overview

    NASA Technical Reports Server (NTRS)

    McPeters, Richard D.; Bhartia, P. K.; Haffner, D.; Labow, Gordon J.; Flynn, Larry

    2013-01-01

    Under a NASA program to produce long-term data records from instruments on multiple satellites, data from a series of nine Solar Backscatter Ultraviolet (SBUV and SBUV2) instruments have been re-processed to create a coherent ozone time series. Data from the BUV instrument on Nimbus 4, SBUV on Nimbus 7, and SBUV2 instruments on NOAA 9, 11, 14, 16, 17, 18, and 19 covering the period 1970-1972 and 1979-2011 were used to create a long-term data set. The goal is an ozone Earth Science Data Record - a consistent, calibrated ozone time series that can be used for trend analyses and other studies. In order to create this ozone data set, the radiances were adjusted and used to re-process the entire data records for each of the nine instruments. Inter-instrument comparisons during periods of overlap as well as comparisons with data from other satellite and ground-based instruments were used to evaluate the consistency of the record and make calibration adjustments as needed. Additional improvements in this version 8.6 processing included the use of the Brion, Daumont, and Malicet ozone cross sections, and a cloud-height climatology derived from Aura OMI measurements. Validation of the re-processed ozone shows that total column ozone is consistent with the Brewer Dobson network to within about 1 for the new time series. Comparisons with MLS, SAGE, sondes, and lidar show that ozone at individual levels in the stratosphere is generally consistent to within 5 percent.

  15. GOME Total Ozone and Calibration Error Derived Usign Version 8 TOMS Algorithm

    NASA Technical Reports Server (NTRS)

    Gleason, J.; Wellemeyer, C.; Qin, W.; Ahn, C.; Gopalan, A.; Bhartia, P.

    2003-01-01

    The Global Ozone Monitoring Experiment (GOME) is a hyper-spectral satellite instrument measuring the ultraviolet backscatter at relatively high spectral resolution. GOME radiances have been slit averaged to emulate measurements of the Total Ozone Mapping Spectrometer (TOMS) made at discrete wavelengths and processed using the new TOMS Version 8 Ozone Algorithm. Compared to Differential Optical Absorption Spectroscopy (DOAS) techniques based on local structure in the Huggins Bands, the TOMS uses differential absorption between a pair of wavelengths including the local stiucture as well as the background continuum. This makes the TOMS Algorithm more sensitive to ozone, but it also makes the algorithm more sensitive to instrument calibration errors. While calibration adjustments are not needed for the fitting techniques like the DOAS employed in GOME algorithms, some adjustment is necessary when applying the TOMS Algorithm to GOME. Using spectral discrimination at near ultraviolet wavelength channels unabsorbed by ozone, the GOME wavelength dependent calibration drift is estimated and then checked using pair justification. In addition, the day one calibration offset is estimated based on the residuals of the Version 8 TOMS Algorithm. The estimated drift in the 2b detector of GOME is small through the first four years and then increases rapidly to +5% in normalized radiance at 331 nm relative to 385 nm by mid 2000. The lb detector appears to be quite well behaved throughout this time period.

  16. 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.

  17. 40 CFR 52.1342 - Control strategy: Ozone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-IL) metropolitan 1997 8-hour ozone nonattainment area has attained the 1997 8-hour ozone NAAQS. This determination, in accordance with 40 CFR 51.918, suspends the requirements for this area to submit an attainment... measures, and other plan elements related to attainment of the standards for as long as the area...

  18. [Radiance Simulation of BUV Hyperspectral Sensor on Multi Angle Observation, and Improvement to Initial Total Ozone Estimating Model of TOMS V8 Total Ozone Algorithm].

    PubMed

    Lü, Chun-guang; Wang, Wei-he; Yang, Wen-bo; Tian, Qing-iju; Lu, Shan; Chen, Yun

    2015-11-01

    New hyperspectral sensor to detect total ozone is considered to be carried on geostationary orbit platform in the future, because local troposphere ozone pollution and diurnal variation of ozone receive more and more attention. Sensors carried on geostationary satellites frequently obtain images on the condition of larger observation angles so that it has higher requirements of total ozone retrieval on these observation geometries. TOMS V8 algorithm is developing and widely used in low orbit ozone detecting sensors, but it still lack of accuracy on big observation geometry, therefore, how to improve the accuracy of total ozone retrieval is still an urgent problem that demands immediate solution. Using moderate resolution atmospheric transmission, MODT-RAN, synthetic UV backscatter radiance in the spectra region from 305 to 360 nm is simulated, which refers to clear sky, multi angles (12 solar zenith angles and view zenith angles) and 26 standard profiles, moreover, the correlation and trends between atmospheric total ozone and backward scattering of the earth UV radiation are analyzed based on the result data. According to these result data, a new modified initial total ozone estimation model in TOMS V8 algorithm is considered to be constructed in order to improve the initial total ozone estimating accuracy on big observation geometries. The analysis results about total ozone and simulated UV backscatter radiance shows: Radiance in 317.5 nm (R₃₁₇.₅) decreased as the total ozone rise. Under the small solar zenith Angle (SZA) and the same total ozone, R₃₁₇.₅ decreased with the increase of view zenith Angle (VZA) but increased on the large SZA. Comparison of two fit models shows: without the condition that both SZA and VZA are large (> 80°), exponential fitting model and logarithm fitting model all show high fitting precision (R² > 0.90), and precision of the two decreased as the SZA and VZA rise. In most cases, the precision of logarithm fitting

  19. 40 CFR 52.2125 - Control strategy: Ozone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... for the 1997 8-hour ozone NAAQS. This determination, in accordance with 40 CFR 51.918, suspends the... 40 Protection of Environment 5 2012-07-01 2012-07-01 false Control strategy: Ozone. 52.2125... strategy: Ozone. (a) Determination of attaining data. EPA has determined, as of November 15, 2011, the...

  20. 40 CFR 52.1779 - Control strategy: Ozone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... for the 1997 8-hour ozone NAAQS. This determination, in accordance with 40 CFR 51.918, suspends the... 40 Protection of Environment 4 2012-07-01 2012-07-01 false Control strategy: Ozone. 52.1779... strategy: Ozone. (a) Determination of attaining data. EPA has determined, as of November 15, 2011, the...

  1. 40 CFR 52.2125 - Control strategy: Ozone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... for the 1997 8-hour ozone NAAQS. This determination, in accordance with 40 CFR 51.918, suspends the... 40 Protection of Environment 5 2014-07-01 2014-07-01 false Control strategy: Ozone. 52.2125... strategy: Ozone. (a) Determination of attaining data. EPA has determined, as of November 15, 2011, the...

  2. 40 CFR 52.1779 - Control strategy: Ozone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... for the 1997 8-hour ozone NAAQS. This determination, in accordance with 40 CFR 51.918, suspends the... 40 Protection of Environment 4 2014-07-01 2014-07-01 false Control strategy: Ozone. 52.1779... strategy: Ozone. (a) Determination of attaining data. EPA has determined, as of November 15, 2011, the...

  3. 40 CFR 52.2125 - Control strategy: Ozone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... for the 1997 8-hour ozone NAAQS. This determination, in accordance with 40 CFR 51.918, suspends the... 40 Protection of Environment 5 2013-07-01 2013-07-01 false Control strategy: Ozone. 52.2125... strategy: Ozone. (a) Determination of attaining data. EPA has determined, as of November 15, 2011, the...

  4. DC-8 during takeoff in Kiruna, Sweden for the second flight of the SAGE III Ozone Loss and Validatio

    NASA Technical Reports Server (NTRS)

    2000-01-01

    NASA's DC-8 taking off from the Kiruna, Sweden, runway in January 2000. The weather at this town of 25,000, located north of the Arctic Circle, can be severe. Temperatures drop as low as 50 degrees below zero Fahrenheit. In December 1999, when the SAGE III Ozone Loss and Validation Experiment (SOLVE) deployment began, there were 20 days of darkness. By mid-January 2000, there was 5 hours of daylight, while in mid-February this increased to nine hours per day. The population of Kiruna extended its hospitality to the SOLVE personnel. On January 22, 2000, the town hosted a dinner for the participants and media attending an open house at the Arena Arctica hangar. At the end of the SOLVE deployment, the airborne science team held an open house for the townspeople at the facility. NASA is using a DC-8 aircraft as a flying science laboratory. The platform aircraft, based at NASA's Dryden Flight Research Center, Edwards, Calif., collects data for many experiments in support of scientific projects serving the world scientific community. Included in this community are NASA, federal, state, academic and foreign investigators. Data gathered by the DC-8 at flight altitude and by remote sensing have been used for scientific studies in archeology, ecology, geography, hydrology, meteorology, oceanography, volcanology, atmospheric chemistry, soil science and biology.

  5. AROTAL Ozone and Temperature Vertical Profile Measurements from the NASA DC-8 during the SOLVE II Campaign

    NASA Technical Reports Server (NTRS)

    McGee, Thomas J.; Twigg, Laurence; Sumnicht, Grant; Hoegy, Walter; Burris, John; Silbert, Donald; Heaps, William; Neuber, R.; Trepte, C. R.

    2004-01-01

    The AROTAL instrument (Airborne Raman Ozone Temperature and Aerosol Lidar) - a collaboration between scientists at NASA Goddard Space Flight Center, and Langley Research Center - was flown on the NASA DC-8 during the SOLVE II Campaign during January and February, 2003. The flights were flown from the Arena Arctica in Kiruna, Sweden. We report measurements of temperature and ozone profiles showing approximately a 600 ppbv loss in ozone near 17.5 km, over the time frame of the aircraft campaign. Comparisons of ozone profiles from AROTAL are made with the SAGE III instrument.

  6. Pulmonary function and symptom responses after 6. 6-hour exposure to 0. 12-ppm ozone with moderate exercise (journal version)

    SciTech Connect

    Folinsbee, L.J.; Horstman, D.H.; McDonnell, W.F.

    1988-01-01

    Episodes occasionally occur when ambient ozone (O/sub 3/) levels remain at or near 0.12 ppm for more than 6 h. The hypothesis that prolonged exposure to 0.12 ppm O/sub 3/ would result in progressively larger changes in respiratory function and symptoms over time was tested. Ten nonsmoking males (18-35 yr) were exposed once to clear air (CA) and once to 0.12 pp, O/sub 3/ for 6.75 h. Exposures consisted of six 50-min exercise periods, each followed by 10-min rest and measurement; a 45-min lunch period followed the third exercise period. Exercise ventilation averaged approximately 40 1/min. Forced expiratory and inspiratory spirometry and respiratory symptoms were measured prior to exposure and after each exercise. Increases in the symptom ratings of cough and pain on deep inspiration were observed with O/sub 3/ exposure but not with CA. Airway reactivity to methacholine was approximately doubled following O/sub 3/ exposure. Spirometry results indicate that prolonged exposure to 0.12 ppm O/sub 3/ results in a marked increase in non-specific airway reactivity and progressive changes in respiratory function.

  7. 30 CFR 48.8 - Annual refresher training of miners; minimum courses of instruction; hours of instruction.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... course component is when there are no explosives used or stored on the mine property. (10) Mine gases... courses of instruction; hours of instruction. 48.8 Section 48.8 Mineral Resources MINE SAFETY AND HEALTH... and in mine conveyances; the controls in effect for the transportation of miners and materials;...

  8. 30 CFR 48.8 - Annual refresher training of miners; minimum courses of instruction; hours of instruction.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... course component is when there are no explosives used or stored on the mine property. (10) Mine gases... courses of instruction; hours of instruction. 48.8 Section 48.8 Mineral Resources MINE SAFETY AND HEALTH... and in mine conveyances; the controls in effect for the transportation of miners and materials;...

  9. 30 CFR 48.8 - Annual refresher training of miners; minimum courses of instruction; hours of instruction.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... course component is when there are no explosives used or stored on the mine property. (10) Mine gases... courses of instruction; hours of instruction. 48.8 Section 48.8 Mineral Resources MINE SAFETY AND HEALTH... and in mine conveyances; the controls in effect for the transportation of miners and materials;...

  10. 30 CFR 48.8 - Annual refresher training of miners; minimum courses of instruction; hours of instruction.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... course component is when there are no explosives used or stored on the mine property. (10) Mine gases... courses of instruction; hours of instruction. 48.8 Section 48.8 Mineral Resources MINE SAFETY AND HEALTH... and in mine conveyances; the controls in effect for the transportation of miners and materials;...

  11. Comparisons of psychosomatic health and unhealthy behaviors between cleanroom workers in a 12-hour shift and those in an 8-hour shift.

    PubMed

    Yamada, Y; Kameda, M; Noborisaka, Y; Suzuki, H; Honda, M; Yamada, S

    2001-12-01

    The General Health Questionnaire (GHQ12) and physical fitness tests were administered to 338 workers in clean rooms producing electronic parts in 12-h shifts. The results were compared to those in 95 workers in 8-h shifts and 284 daytime management, clerical and engineering workers. The 12-h shift workers complained of poor health, dissatisfaction with life and poor recuperation from fatigue more than the 8-h shift workers although the rates of complaints were highest in the daytime workers. The GHQ scores were similar in the two shift groups, and much better than those in the daytime workers. However, the 12-h shift workers showed significantly lower fitness levels than the 8-h shift workers, and the levels were even worse than the daytime workers who had higher mean age and BMI levels compared with the shift workers. The tendency to have sedentary freetime activities and larger alcohol and cigarette consumption were observed in the 12-h shift workers. The 12-h shift work may have contributed to the unhealthy behaviors resulting in lower physical fitness levels. Health promotion services at the workplace should devote greater attention to long-hour shift workers, together with devising the ways to improve working conditions and environments for reducing fatigue at work.

  12. Version 8 SBUV Ozone Profile Trends Compared with Trends from a Zonally Averaged Chemical Model

    NASA Technical Reports Server (NTRS)

    Rosenfield, Joan E.; Frith, Stacey; Stolarski, Richard

    2004-01-01

    Linear regression trends for the years 1979-2003 were computed using the new Version 8 merged Solar Backscatter Ultraviolet (SBUV) data set of ozone profiles. These trends were compared to trends computed using ozone profiles from the Goddard Space Flight Center (GSFC) zonally averaged coupled model. Observed and modeled annual trends between 50 N and 50 S were a maximum in the higher latitudes of the upper stratosphere, with southern hemisphere (SH) trends greater than northern hemisphere (NH) trends. The observed upper stratospheric maximum annual trend is -5.5 +/- 0.9 % per decade (1 sigma) at 47.5 S and -3.8 +/- 0.5 % per decade at 47.5 N, to be compared with the modeled trends of -4.5 +/- 0.3 % per decade in the SH and -4.0 +/- 0.2% per decade in the NH. Both observed and modeled trends are most negative in winter and least negative in summer, although the modeled seasonal difference is less than observed. Model trends are shown to be greatest in winter due to a repartitioning of chlorine species and the increasing abundance of chlorine with time. The model results show that trend differences can occur depending on whether ozone profiles are in mixing ratio or number density coordinates, and on whether they are recorded on pressure or altitude levels.

  13. DC-8 and ER-2 in Sweden for the Sage III Ozone Loss and Validation Experiment (SOLVE)

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This 48 second video shows Dryden's Airborne Science aircraft in Kiruna Sweden in January 2000. The DC-8 and ER-2 conducted atmospheric studies for the Sage III Ozone Loss and Validation Experiment (SOLVE).

  14. Radial diffusive samplers for determination of 8-h concentration of BTEX, acetone, ethanol and ozone in ambient air during a sea breeze event

    NASA Astrophysics Data System (ADS)

    Roukos, Joelle; Locoge, Nadine; Sacco, Paolo; Plaisance, Hervé

    2011-01-01

    The radial diffusive sampler Radiello ® filled with Carbograph 4 was evaluated for monitoring BTEX, ethanol and acetone concentrations for 8-hour exposure time. The sampling rates were first evaluated in an exposure chamber under standard conditions. Benzene and toluene showed the highest sampling rates with satisfactory standard deviations. Ethylbenzene and xylenes showed medium sampling rates but higher standard deviations that can be attributed to a low affinity of these compounds with the adsorbent medium for short sampling time. Acetone has a fair result because of the increase of its partial pressure in the vicinity of the adsorbent surface in the course of sampling. The Carbograph 4 adsorbent does not seem to be suitable for sampling ethanol, likely because of its high volatility. The influences of three environmental factors (temperature (T), relative humidity (RH) and concentration level (C)) on the sampling rates were also evaluated, following a fractional factorial design at two factor levels (low and high). Results were only investigated on benzene, toluene and acetone. Temperature and relative humidity are found to be the most important factors leading to variability of the benzene and toluene sampling rates. The applicability of the sampler for 8-hour sampling was demonstrated by the results of a measurement campaign carried out during a sea breeze event. Mapping of benzene, toluene and acetone concentrations showed the highest concentrations in the industrial zone following the wind direction coming from the North. Nevertheless, the sea breeze tends to reduce the spread of the industrial plumes. On the contrary, the ozone map presents the lowest concentrations at the same industrial area indicating a net consumption of ozone. The highest ozone concentrations were found in the southeastern zone suggesting a local ozone formation.

  15. Assimilation of SBUV Version 8 Radiances into the GEOS Ozone DAS

    NASA Technical Reports Server (NTRS)

    Mueller, Martin D.; Stajner, Ivanka; Bhartia, Pawan K.

    2004-01-01

    In operational weather forecasting, the assimilation of brightness temperatures from satellite sounders, instead of assimilation of 1D-retrievals has become increasingly common practice over the last two decades. Compared to these systems, assimilation of trace gases is still at a relatively early stage of development, and efforts to directly assimilate radiances instead of retrieved products have just begun a few years ago, partially because it requires much more computation power due to the employment of a radiative transport forward model (FM). This paper will focus on a method to assimilate SBUV/2 radiances (albedos) into the Global Earth Observation System Ozone Data Assimilation Scheme (GEOS-03DAS). While SBUV-type instruments cannot compete with newer sensors in terms of spectral and horizontal resolution, they feature a continuous data record back to 1978, which makes them very valuable for trend studies. Assimilation can help spreading their ground coverage over the whole globe, as has been previously demonstrated with the GEOS-03DAS using SBUV Version 6 ozone profiles. Now, the DAS has been updated to use the newly released SBUV Version 8 data. We will compare pre]lmlnarv results of SBUV radiance assimilation with the assimilation of retrieved ozone profiles, discuss methods to deal with the increased computational load, and try to assess the error characteristics and future potential of the new approach.

  16. 40 CFR 51.913 - How do the section 182(f) NOX exemption provisions apply for 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 How do the section 182(f) NOX exemption... How do the section 182(f) NOX exemption provisions apply for the 8-hour NAAQS? (a) A person may petition the Administrator for an exemption from NOX obligations under section 182(f) for any...

  17. 40 CFR 51.913 - How do the section 182(f) NOX exemption provisions apply for 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 How do the section 182(f) NOX exemption... How do the section 182(f) NOX exemption provisions apply for the 8-hour NAAQS? (a) A person may petition the Administrator for an exemption from NOX obligations under section 182(f) for any...

  18. ER-2 #809 and DC-8 in Arena Arctica hangar in Kiruna, Sweden prior to the SAGE III Ozone Loss and Va

    NASA Technical Reports Server (NTRS)

    2000-01-01

    NASA ER-2 # 809 and its DC-8 shown in Arena Arctica before the SAGE III Ozone Loss and Validation Experiment (SOLVE). The two airborne science platforms were based north of the Arctic Circle in Kiruna, Sweden, during the winter of 2000 to study ozone depletion as part of SOLVE. A large hangar built especially for research, 'Arena Arctica' housed the instrumented aircraft and the scientists. Scientists have observed unusually low levels of ozone over the Arctic during recent winters, raising concerns that ozone depletion there could become more widespread as in the Antarctic ozone hole. The NASA-sponsored international mission took place between November 1999 and March 2000 and was divided into three phases. The DC-8 was involved in all three phases returning to Dryden between each phase. The ER-2 flew sample collection flights between January and March, remaining in Sweden from Jan. 9 through March 16. 'The collaborative campaign will provide an immense new body of information about the Arctic stratosphere,' said program scientist Dr. Michael Kurylo, NASA Headquarters. 'Our understanding of the Earth's ozone will be greatly enhanced by this research.' ER-2s bearing tail numbers 806 and 809 are used as airborne science platforms by NASA's Dryden Flight Research Center. The aircraft are platforms for a variety of high-altitude science missions flown over various parts of the world. They are also used for earth science and atmospheric sensor research and development, satellite calibration and data validation. The ER-2s are capable of carrying a maximum payload of 2,600 pounds of experiments in a nose bay, the main equipment bay behind the cockpit, two wing-mounted superpods and small underbody and trailing edges. Most ER-2 missions last about six hours with ranges of about 2,200 nautical miles. The aircraft typically fly at altitudes above 65,000 feet. On November 19, 1998, an ER-2 set a world record for medium weight aircraft reaching an altitude of 68,700 feet. The

  19. 76 FR 28195 - Approval and Promulgation of Air Quality Implementation Plans; New Mexico; Sunland Park 1-Hour...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-16

    ... attainment of the 8-hour ozone National Ambient Air Quality Standard (NAAQS) through the year 2014. The... AGENCY 40 CFR Part 52 Approval and Promulgation of Air Quality Implementation Plans; New Mexico; Sunland Park 1-Hour Ozone Maintenance Plan AGENCY: Environmental Protection Agency (EPA). ACTION: Proposed...

  20. Defeathering of broiler carcasses subjected to delayed scalding 1, 2, 4, and 8 hours after slaughter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    With implementation of farm slaughter, scalding and defeathering could be delayed for a minimum of 2 to 4 h. This research evaluated the potential for delaying scalding and defeathering up to 8 h after slaughter. Following 12 h feed withdrawal broilers were cooped and transported to the pilot plan...

  1. 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

    ..., 2008, EPA promulgated revised 8-hour primary and secondary ozone NAAQS (73 FR 16436; March 27, 2008... 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...

  2. 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...

  3. 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...

  4. 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

    ... set at a more stringent level. \\1\\ See 73 FR 16436. \\2\\ The secondary ozone standard, designed to... 1-hour ozone NAAQS, see 56 FR 56694. \\8\\ See 40 CFR Appendix I. \\9\\ Referred to as the Phase 1 Rule... the 1997 ozone NAAQS. (See 69 FR 23954). The Phase 1 rule also established comprehensive...

  5. 40 CFR 52.2043 - Control strategy for maintenance plans: ozone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...: ozone. 52.2043 Section 52.2043 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Control strategy for maintenance plans: ozone. (a) As of December 26, 2013, EPA approves the following... (VOCs) for the Lancaster 1997 8-Hour Ozone Maintenance Area submitted by the Secretary of...

  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, 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...

  8. 40 CFR 52.2052 - Motor vehicle emissions budgets for Pennsylvania ozone areas.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Pennsylvania ozone areas. 52.2052 Section 52.2052 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY...) Pennsylvania § 52.2052 Motor vehicle emissions budgets for Pennsylvania ozone areas. (a) As of December 26... nitrogen oxides (NOX) and volatile organic compounds (VOCs) for the Lancaster 1997 8-Hour Ozone...

  9. 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...

  10. Behavioral changes in neonatal swine after an 8-hour rest during prolonged transportation.

    PubMed

    Williams, J L; Richert, B T; Marchant-Forde, J N; Eicher, S D

    2012-09-01

    Long distance transportation of weaned piglets (Sus scrofa) is increasingly common in the united states and may result in delayed eating, drinking, or normal social behaviors. A potential solution is a mid-journey rest (lairage). The objective of this study was to determine if a lairage altered behavior after a 16-h transport. Pigs that weighed approximately 18 kg each (n = 894) were housed in 16 pens with 8 pens per treatment. Lairaged pigs were transported for 8 h and given an 8-h rest with food and water, whereas control pigs were transported continuously for 16 h. The heaviest, the lightest, and 2 average-BW pigs relative to the average weight of the pen were observed by video recording for 24 h immediately before and after transport, and during d 6 and 13 after transport. Postures (lying, sitting, and standing) were recorded using 10-min-interval scan sampling, and behavioral categories included inactivity, activities (eating, drinking, alert, manipulating pen, rooting, and walking) and social interactions (aggression, belly nosing, playing, tail biting, and positive social behaviors). In both treatments, sitting occurred most before transport (P < 0.01) than at other times, but did not differ between treatments. Standing increased (time effect; P < 0.01) for both treatments immediately after transport through d 6, but returned to pre-transport values by d 13. In contrast, lying decreased (time effect; P < 0.01) after transport, but returned to above pre-transport values by d 13. Time effects were evident for activity (P < 0.01), pen manipulation (P = 0.05), rooting (P < 0.01), initiation of belly-nosing (P = 0.01), and receiving belly-nosing (P = 0.03); however, initiation of aggression did not differ for day (P = 0.19) or treatment (P = 0.56). Lairaged pigs initiated more (P = 0.05) play than continuously transported pigs, but no differences (P = 0.84) were seen in receipt of play behavior. Pigs that were to be transported for 16 h continuously walked less

  11. Observation of gamma rays with a 4.8 hour periodicity from CYG X-3

    NASA Technical Reports Server (NTRS)

    Lamb, R. C.; Fichtel, C. E.; Hartman, R. C.; Kniffen, D. A.; Thompson, D. J.

    1976-01-01

    Energetic (E35 MeV) Gamma rays were observed from Cyg X-3 with the SAS-2 Gamma ray telescope. They are modulated at the 4.8 sup h period observed in the X-ray and infrared regions, and within the statistical error are in phase with this emission. The flux above 100 MeV has an average value of (4.4 + or - 1.1)x 10 to the -6 power/sq cm/sec. If the distance to Cyg X-3 is 10 kpcs, this flux implies a luminosity of more than 10 to the 37th power ergs/s if the radiation is isotropic and about 10 to the 36th power ergs/s if the radiation is restricted to a cone of one steradian, as it might be in a pulsar.

  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, 2011 CFR

    2011-07-01

    ... waiver of the ozone monitoring requirement would be handled under provisions of 40 CFR, part 58. Some... year unless the appropriate Regional Administrator has granted a waiver under the provisions of 40 CFR... and Secondary National Ambient Air Quality Standards for Ozone H Appendix H to Part 50 Protection...

  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, 2013 CFR

    2013-07-01

    ... waiver of the ozone monitoring requirement would be handled under provisions of 40 CFR, part 58. Some... year unless the appropriate Regional Administrator has granted a waiver under the provisions of 40 CFR... and Secondary National Ambient Air Quality Standards for Ozone H Appendix H to Part 50 Protection...

  14. 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

    ... waiver of the ozone monitoring requirement would be handled under provisions of 40 CFR, part 58. Some... year unless the appropriate Regional Administrator has granted a waiver under the provisions of 40 CFR... and Secondary National Ambient Air Quality Standards for Ozone H Appendix H to Part 50 Protection...

  15. Lung Function and Inflammatory responses in healthy young adults exposed to 0.06 ppm Ozone for 6.6 hours

    EPA Science Inventory

    Rationale: Exposure to ozone causes a decrease in spirometric lung function and an increase in airway inflammation in healthy young adults at concentrations as low as 0.08 ppm close to the the National Ambient Air Quality Standard for ground level ozone. Objectives: To test wheth...

  16. 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

    ... waiver of the ozone monitoring requirement would be handled under provisions of 40 CFR, part 58. Some... year unless the appropriate Regional Administrator has granted a waiver under the provisions of 40 CFR... and Secondary National Ambient Air Quality Standards for Ozone H Appendix H to Part 50 Protection...

  17. A 15,000-hour cyclic endurance test of an 8-centimeter-diameter electron bombardment mercury ion thruster

    NASA Technical Reports Server (NTRS)

    Nakanishi, S.

    1976-01-01

    A laboratory model 8 cm thruster with improvements to minimize ion chamber erosion and peeling of sputtered metal was subjected to a cyclic endurance test for 15,040 hours and 460 restarts. A charted history of several thruster operating variables and off-normal events are shown in 600-hour segments at three points in the test. The transient behavior of these variables during a typical start-stop cycle is presented. Finding of the post-test inspection confirmed most of the expected results. Charge exchange ions caused normal accelerator grid erosion. The workability of the various design features was substantiated, and attainable improvements in propellant utilization efficiency should significantly reduce accelerator erosion.

  18. Reactions of vitamin E and its model compound 2,2,5,7,8-pentamethylchroman-6-ol with ozone

    SciTech Connect

    Liebler, D.C.; Matsumoto, Shigenobu; Matsuo, Mitsuyoshi; Iitaka, Yoichi

    1993-01-01

    Reaction of vitamin E [(R,R,R,)-{alpha}-tocopherol] with ozone in acetonitrile yielded {alpha}-tocopheryl quinone and its precursor 8{alpha}-hydroxytocopherone, which accounted for approximately 30% of the products at <50% {alpha}-tocopherol oxidation. In addition, two novel products were identified as epimers of 10-acetyl-7-(4{prime},8{prime},12{prime}-trimethyl tridecyl)-3,4,7-trimethyl-2-oxo - 1,6-dioxaspiro[4.5]-deca-3,9-diene. These spiro products were formed in equal amounts in a combined yield of approximately 33% after complete {alpha}-tocpherol oxidation. Ozonation of the vitamin E model compound 2,2,5,7,8-pentamethylchroman-6-ol yielded an analogous spiro product, 10-acetyl-3,4,7,7-tetramethyl-2-oxo-1,6-dioxaspiro[4.5]deca-3,9-diene, whose structure was confirmed by X-ray crystallography. The spiro products may be formed by ozone addition to the chroman ring and subsequent rearrangement to ring-opened hydroxyacid products, which yield spiro products by ring closure due to dehydration. Novel spiro products formed by ozonation of vitamin E may be unique markers of ozone interaction with lipid structures that contain vitamin E. 39 refs., 3 figs., 1 tab.

  19. Comparison of Temperature and Ozone Measured by the AROTEL Instrument on DC8 Overflights of Ny Aalesund during the SOLVE Mission

    NASA Technical Reports Server (NTRS)

    Hoegy, Walter R.; McGee, Thomas J.; Burris, John F.; Heaps, William; Silbert, Donald; Sumnicht, Grant; Twigg, Laurence; Neuber, Roland

    2000-01-01

    The AROTEL instrument, deployed on the NASA DC-8 at Kiruna, Sweden for the SAGE III Ozone Loss and Validation Experiment (SOLVE), flew over the NDSC station operated by the Alfred Wegner Institute at Ny Aalesund, Spitsbergen. AROTEL ozone and temperature measurements made during near overflights of Ny Aalesund are compared with sonde ozone and temperature, and lidar ozone measurements from the NDSC station. Nine of the seventeen science flights during the December through March measurement period overflew near Ny Aalesund. Agreement of AROTEL with the ground-based temperature and ozone values at altitudes from just above the aircraft to about 30 km gives strong confidence in using AROTEL temperature and ozone mixing ratio to study the mechanisms of ozone loss in the winter arctic polar region.

  20. Evaluation of lightning-induced tropospheric ozone enhancements observed by ozone lidar and simulated by WRF/Chem

    NASA Astrophysics Data System (ADS)

    Wang, Lihua; Follette-Cook, Melanie B.; Newchurch, M. J.; Pickering, Kenneth E.; Pour-Biazar, Arastoo; Kuang, Shi; Koshak, William; Peterson, Harold

    2015-08-01

    High spatial- and temporal-resolution ozone lidar profiles, in conjunction with ozonesonde and satellite observations, are well suited to characterize short-term ozone variations due to different physical and chemical processes, such as the impact of lightning-generated NOx (LNOx) on tropospheric ozone. This work presents the hourly variation of tropospheric-ozone profiles measured by an ozone lidar at the University of Alabama in Huntsville, on July 14, 18, and 27, 2011. These ozone lidar data are compared with two WRF/Chem simulations, one with lightning NO (LNO) emissions and the other without. On July 14, 2011, the ozone lidar observed an ozone laminar structure with elevated ozone concentrations of 65∼80 ppbv below 2 km, low ozone (50∼65) ppbv between 2 and 5 km, and high ozone up to 165 ppbv between 5 and 12 km AGL. WRF/Chem simulations, in conjunction with backward trajectory analysis, suggest that lightning events occurring within upwind regions resulted in an ozone enhancement of 28 ppbv at 7.5 km AGL over Huntsville. On July 27, LNO emissions were transported to Huntsville from upwind and account for 75% of NOx and an 8.3 ppbv of ozone enhancement at ∼10 km; the model overestimates ozone between 2.5 and 5 km AGL.

  1. Cerebral blood flow determination within the first 8 hours of cerebral infarction using stable xenon-enhanced computed tomography

    SciTech Connect

    Hughes, R.L.; Yonas, H.; Gur, D.; Latchaw, R.

    1989-06-01

    Cerebral blood flow mapping with stable xenon-enhanced computed tomography (Xe/CT) was performed in conjunction with conventional computed tomography (CT) within the first 8 hours after the onset of symptoms in seven patients with cerebral infarction. Six patients had hemispheric infarctions, and one had a progressive brainstem infarction. Three patients with very low (less than 10 ml/100 g/min) blood flow in an anatomic area appropriate for the neurologic deficit had no clinical improvement by the time of discharge from the hospital; follow-up CT scans of these three patients confirmed infarction in the area of very low blood flow. Three patients with moderate blood flow reductions (15-45 ml/100 g/min) in the appropriate anatomic area had significant clinical improvement from their initial deficits and had normal follow-up CT scans. One patient studied 8 hours after stroke had increased blood flow (hyperemia) in the appropriate anatomic area and made no clinical recovery.

  2. Alertness, performance and off-duty sleep on 8-hour and 12-hour night shifts in a simulated continuous operations control room setting

    SciTech Connect

    Baker, T.L.

    1995-04-01

    A growing number of nuclear power plants in the United States have adopted routine 12-hr shift schedules. Because of the potential impact that extended work shifts could have on safe and efficient power plant operation, the U.S. Nuclear Regulatory Commission funded research on 8-hr and 12-hr shifts at the Human Alertness Research Center (HARC) in Boston, Massachusetts. This report describes the research undertaken: a study of simulated 8-hr and 12-hr work shifts that compares alertness, speed, and accuracy at responding to simulator alarms, and relative cognitive performance, self-rated mood and vigor, and sleep-wake patterns of 8-hr versus 12-hr shift workers.

  3. 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

    ... discussion of EPA's rationale for applying this interpretation in the Phase 2 Rule, see 70 FR at 71647- 49... FR 71612, November 29, 2005). \\2\\ The memorandum is available on the EPA Technology and Transfer... approach for crediting reductions from outside nonattainment areas (``outside'' reductions). See 72...

  4. 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

    ... Order Reviews I. Proposed Action On April 11, 2012 (70 FR 21690), EPA proposed to approve the ``Eight... Budget under Executive Order 12866 (58 FR 51735, October 4, 1993); Does not impose an information...); Does not have Federalism implications as specified in Executive Order 13132 (64 FR 43255, August...

  5. 76 FR 3840 - Approval of One-Year Extension for Attaining the 1997 8-Hour Ozone Standard for the Delaware...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-21

    ... November 9, 2010 (75 FR 68736), EPA published a notice of proposed rulemaking (NPR) for the States. The NPR... Executive Order Reviews A. General Requirements Under Executive Order 12866 (58 FR 51735, October 4, 1993...'' (66 FR 28355, May 22, 2001). This action merely approves state law as meeting Federal requirements...

  6. 76 FR 3838 - Approval and Promulgation of One-Year Extension for Attaining the 1997 8-Hour Ozone Standard for...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-21

    ... attainment date be extended to June 15, 2011. On November 9, 2010 (75 FR 68733), EPA proposed to approve New...).'' IV. Statutory and Executive Order Reviews Under Executive Order 12866 (58 FR 51735, October 4, 1993...'' (66 FR 28355 (May 22, 2001)). This action merely finds that an area has qualified for a...

  7. 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

    ...'' subject to review by the Office of Management and Budget under Executive Order 12866 (58 FR 51735, October... Executive Order 13132 (64 FR 43255, August 10, 1999); Is not an economically significant regulatory action based on health or safety risks subject to Executive Order 13045 (62 FR 19885, April 23, 1997); ] Is...

  8. 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

    ... Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use'' (66 FR 28355 (May 22... From the Federal Register Online via the Government Publishing Office ENVIRONMENTAL PROTECTION... Baltimore Moderate Nonattainment Area AGENCY: Environmental Protection Agency (EPA). ACTION: Direct...

  9. 78 FR 34906 - Approval and Promulgation of Air Quality Implementation Plans; Ohio; Lima 1997 8-Hour Ozone...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-11

    ... the following methods: 1. www.regulations.gov : Follow the on-line instructions for submitting....regulations.gov , including any personal information provided, unless the comment includes information claimed....regulations.gov or email. The www.regulations.gov Web site is an ``anonymous access'' system, which means...

  10. 75 FR 43114 - 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

    ... the following methods: A. http://www.regulations.gov . Follow the on-line instructions for submitting... the use of special characters, any form of encryption, and be free of any defects or viruses....

  11. 75 FR 16456 - Adequacy Status of the Beaumont-Port Arthur, TX Maintenance Plan; 8-Hour Ozone Motor Vehicle...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-01

    ...; Transportation Conformity Rule Amendments: Response to Court Decision and Additional Rule Changes'' (69 FR 40004... been made, pursuant to 40 CFR 93.104(e). See, 73 FR 4419 (January 24, 2008). Authority: 42 U.S.C. 7401... motor vehicle emissions budgets (MVEB) in the Beaumont-Port Arthur, Texas (BPA) Redesignation...

  12. 75 FR 55977 - Adequacy Status of the Knoxville, TN 1997 8-Hour Ozone Maintenance Plan Motor Vehicle Emission...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-09-15

    ... Additional Rule Changes'' (69 FR 40004). Please note that an adequacy review is separate from EPA's... made, pursuant to 40 CFR 93.104(e). See 73 FR 4419 (January 24, 2008). Authority: 42 U.S.C. 7401 et seq... Vehicle Emission Budgets for Transportation Conformity Purposes AGENCY: Environmental Protection...

  13. 76 FR 28223 - Adequacy Status of the Baton Rouge, Louisiana Maintenance Plan 8-Hour Ozone Motor Vehicle...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-16

    ... Additional Rule Changes'' (69 FR 40004). Please note that an adequacy review is separate from EPA's... the new MVEB if the demonstration has not already been made, pursuant to 40 CFR 93.104(e). See, 73 FR... Emission Budgets for Transportation Conformity Purposes AGENCY: Environmental Protection Agency...

  14. 78 FR 7429 - Adequacy Status of the Dallas-Fort Worth, TX Reasonable Further Progress 8-Hour Ozone Motor...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-01

    ...: Response to Court Decision and Additional Rule Changes'' (69 FR 40004). Please note that an adequacy review..., pursuant to 40 CFR 93.104(e). See, 73 FR 4419 (January 24, 2008). Authority: 42 U.S.C. 7401 et seq. Dated... Vehicle Emission Budgets for Transportation Conformity Purposes AGENCY: Environmental Protection...

  15. 75 FR 9893 - Adequacy Determination for the Denver Metro Area and North Front Range 8-Hour Ozone Attainment...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-04

    ... North Front Range Metropolitan Planning Organization (NFR MPO), the Colorado Department of...) which was promulgated August 15, 1997 (see 62 FR 43780). We described our process for determining the adequacy of submitted SIP MVEBs in our July 1, 2004 Transportation Conformity Rule Amendments (see 69...

  16. 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

    .../Projects/Project.asp?CMSID2=1120 &MID=Environmental%20Programs. In June 2007, the United States Court of... documentation in their submittals explaining how the emissions data were calculated. See 70 FR 71612 (Nov. 29... is proposing to approve revisions to the Arizona state implementation plan (SIP) that...

  17. 40 CFR 52.582 - Control strategy: Ozone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... area has attaining data for the 1997 8-hour ozone NAAQS. This determination, in accordance with 40 CFR... satisfies 40 CFR 58.20(f) which requires the State to provide for the establishment and maintenance of... 40 Protection of Environment 3 2012-07-01 2012-07-01 false Control strategy: Ozone. 52.582...

  18. 40 CFR 52.582 - Control strategy: Ozone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... data for the 1997 8-hour ozone NAAQS. This determination, in accordance with 40 CFR 51.918, suspends..., into the Georgia State Implementation Plan. This submittal satisfies 40 CFR 58.20(f) which requires the... 40 Protection of Environment 3 2011-07-01 2011-07-01 false Control strategy: Ozone. 52.582...

  19. 40 CFR 52.582 - Control strategy: Ozone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... area has attaining data for the 1997 8-hour ozone NAAQS. This determination, in accordance with 40 CFR... satisfies 40 CFR 58.20(f) which requires the State to provide for the establishment and maintenance of... 40 Protection of Environment 3 2014-07-01 2014-07-01 false Control strategy: Ozone. 52.582...

  20. Issues with ozone attainment methodology for Houston, TX.

    PubMed

    Vizuete, William; Jeffries, Harvey E; Tesche, T W; Olaguer, Eduardo P; Couzo, Evan

    2011-03-01

    To comply with the federal 8-hr ozone standard, the state of Texas is creating a plan for Houston that strictly follows the U.S. Environmental Protection Agency's (EPA) guidance for demonstrating attainment. EPA's attainment guidance methodology has several key assumptions that are demonstrated to not be completely appropriate for the unique observed ozone conditions found in Houston. Houston's ozone violations at monitoring sites are realized as gradual hour-to-hour increases in ozone concentrations, or by large hourly ozone increases that exceed up to 100 parts per billion/hr. Given the time profiles at the violating monitors and those of nearby monitors, these large increases appear to be associated with small parcels of spatially limited plumes of high ozone in a lower background of urban ozone. Some of these high ozone parcels and plumes have been linked to a combination of unique wind conditions and episodic hydrocarbon emission events from the Houston Ship Channel. However, the regulatory air quality model (AQM) does not predict these sharp ozone gradients. Instead, the AQM predicts gradual hourly increases with broad regions of high ozone covering the entire Houston urban core. The AQM model performance can be partly attributed to EPA attainment guidance that prescribes the removal in the baseline model simulation of any episodic hydrocarbon emissions, thereby potentially removing any nontypical causes of ozone exceedances. This paper shows that attainment of all monitors is achieved when days with observed large hourly variability in ozone concentrations are filtered from attainment metrics. Thus, the modeling and observational data support a second unique cause for how ozone is formed in Houston, and the current EPA methodology addresses only one of these two causes.

  1. GSTM1 modulation of IL-8 expression in human epithelial cells exposed to ozone

    EPA Science Inventory

    Exposure to the major air pollutant ozone can aggravate asthma and other lung diseases. Our recent study in humanvolunteers hasshown that the glutathione S-transferase Mu 1(GSTMI)-null genotype is associated with increased airway neutrophilic inflammation induced by inhaled ozone...

  2. Ozone trends in California`s South Coast Air Basin, 1976--1996

    SciTech Connect

    Cohanim, S.; Cassmassi, J.; Bassett, M.

    1998-12-31

    The South Coast Air Basin (Basin) of Southern California exhibits the worst air quality in the nation, as measured by the annual number of days exceeding the 1-hour National Ambient Air Quality Standard (NAAQS) for ozone. Hourly pollutant concentration data collected by the South Coast Air Quality Management District`s air monitoring network are compared to the existing 1-hour and new 8-hour federal ozone ambient air quality standards to depict ozone trends and compliance in the Basin. Results of trend analyses for the different areas of the Basin are presented for the 1-hour and 8-hour standards, and the relative stringency of the existing and new federal standards is examined. Based on an analysis of the effect of the recently adopted federal standard on ozone compliance in the Basin, ozone concentrations exceed the new federal 8-hour standard level more often than the existing 1-hour standard in most locations. However, examination of the trends in design values for the 1-hour and 8-hour ozone standards suggests that for most locations in the Basin the new standard probably should not be significantly more difficult to attain than the existing standard. The weather-adjusted ozone trend analysis in the Basin confirms the fact that the downtrends in ozone concentrations and number of days exceeding standards are real and independent of annual variation in weather. An analysis of weekday/weekend differences in exceedances for the existing 1-hour and new 8-hour ozone standards show a higher number of days exceeding both standards on weekends for most locations in the Basin, with differences being more evident in the 1990s than in the late 1970s and 1980s

  3. Ozone dynamics and snow-atmosphere exchanges during ozone depletion events at Barrow, Alaska

    NASA Astrophysics Data System (ADS)

    Helmig, Detlev; Boylan, Patrick; Johnson, Bryan; Oltmans, Sam; Fairall, Chris; Staebler, Ralf; Weinheimer, Andrew; Orlando, John; Knapp, David J.; Montzka, Denise D.; Flocke, Frank; Frieß, Udo; Sihler, Holger; Shepson, Paul B.

    2012-10-01

    The behavior of lower atmospheric ozone and ozone exchanges at the snow surface were studied using a suite of platforms during the Ocean-Atmosphere-Sea Ice-Snow (OASIS) Spring 2009 experiment at an inland, coastal site east of Barrow, Alaska. A major objective was to investigate if and how much chemistry at the snow surface at the site contributes to springtime ozone depletion events (ODEs). Between March 8 and April 16, seven ODEs, with atmospheric ozone dropping below 1.0 ppbv, were observed. The depth of the ozone-depleted layer was variable, extending from the surface to ˜200-800 m. ODEs most commonly occurred during low wind speed conditions with flow coming from the Arctic Ocean. Two high-sensitivity ozone chemiluminescence instruments were used to accurately define the remaining sub-ppbv ozone levels during ODEs. These measurements showed variable residual ODE ozone levels ranging between 0.010 and 0.100 ppbv. During the most extended ODE, when ozone remained below 1.0 ppbv for over 78 h, these measurements showed a modest ozone recovery or production in the early afternoon hours, resulting in increases in the ozone mixing ratio of 0.100 to 0.800 ppbv. The comparison between high-sensitivity ozone measurements and BrO measured by longpath differential absorption spectroscopy (DOAS) during ODEs indicated that at low ozone levels formation of BrO is controlled by the amount of available ozone. Measurements of ozone in air drawn from below the snow surface showed depleted ozone in the snowpack, with levels consistently remaining <6 ppbv independent of above-surface ambient air concentrations. The snowpack was always a sink of ozone. Ozone deposition velocities determined from ozone surface flux measurements by eddy covariance were on the order of 0.01 cm s-1, which is of similar magnitude as ozone uptake rates found over snow at other polar sites that are not subjected to ODEs. The results from these multiple platform measurements unequivocally show that snow

  4. 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

    ... Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS NATIONAL PRIMARY AND SECONDARY AMBIENT... determining the expected number of annual exceedances relate to accounting for incomplete sampling. In general... waiver of the ozone monitoring requirement would be handled under provisions of 40 CFR, part 58....

  5. Extended workdays: Effects of 8-hour and 12-hour rotating shift schedules on test performance, subjective alertness, sleep patterns, and psychological variables

    SciTech Connect

    Rosa, R.R.; Colligan, M.J.; Lewis, P.

    1986-06-01

    A newly instituted 3 to 4 day/12-hr rotating shift schedule was compared to the previous 5 to 7 day/8-hr schedule using standard laboratory-type measures of performance and alertness, and a questionnaire on sleep patterns and other personal habits. After seven months adaptation to the new schedule, a preliminary analysis indicates that there were some decrements in alertness, reductions in sleep, and disruptions of other personal activities during 12-hr workdays. Gastro-intestinal state improved during night shift, however, and increases in self-reported stress were reduced by the shortened workweek. These results are discussed in terms of trade-offs between longer workdays and shorter workweeks. It is emphasized that at this time no determination can be made of the extent of risk associated with these changes in alertness.

  6. Evaluation of Global Model Simulation of Tropospheric Ozone from ECHAM6-HAMMOZ1 with Surface Measurements over the Mediterranean Region

    NASA Astrophysics Data System (ADS)

    Kaffashzadeh, Najmeh; Schultz, Martin G.; Lyapina, Olga; Schröder, Sabine; Stadtler, Scarlet

    2016-04-01

    Current chemistry transport models are generally successful in describing the principle features of the present-day global tropospheric ozone (O3) distribution, but they exhibit large differences of ozone concentrations over the Mediterranean region. The Mediterranean region can be perturbed by long-range pollution import from Northern Europe, North Africa and Asia, in addition to local emissions, which may all contribute to ozone concentrations in this area. Identifying the main drivers for Mediterranean ozone concentrations and understanding the reasons for the inter-model differences remain scientific challenges. To investigate the geographical distribution of tropospheric ozone over the Mediterranean, we analyze hourly surface ozone measurements from more than 1000 stations in the Tropospheric Ozone Assessment Report (TOAR) database and compare these to hourly model outputs from the global chemistry climate model ECHAM6-HAMMOZ1 for the year 2012. The daily maximum 8-hour running mean value of ozone mixing ratios is calculated for both model and observation and compared. The preliminary results show that the model captures many features of the ozone and its precursor concentrations in many regions of Europe throughout the year. However, it substantially underestimates ozone in the Po Valley region in summer and overestimates ozone over much of the Mediterranean region during spring. The reasons for this behavior will be investigated through detailed sensitivity studies with respect to VOC emissions, anthropogenic emissions, ozone deposition, specific chemical reactions, and long range-import of ozone and precursors.

  7. 78 FR 25236 - Approval and Promulgation of Implementation Plans; New York; Infrastructure SIP for the 1997 8...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-30

    ... information? On July 18, 1997, EPA promulgated new and revised NAAQS for 8-hour ozone (62 FR 38856) and PM 2.5 (62 FR 38652). The ozone NAAQS is based on 8-hour average concentrations. The 8-hour averaging period.... EPA strengthened the 24-hour PM 2.5 NAAQS from 65 g/m\\3\\ to 35 g/m\\3\\ on October 17, 2006 (71 FR...

  8. Ozone reaction with interior building materials: Influence of diurnal ozone variation, temperature and humidity

    NASA Astrophysics Data System (ADS)

    Rim, Donghyun; Gall, Elliott T.; Maddalena, Randy L.; Nazaroff, William W.

    2016-01-01

    Elevated tropospheric ozone concentrations are associated with increased morbidity and mortality. Indoor ozone chemistry affects human exposure to ozone and reaction products that also may adversely affect health and comfort. Reactive uptake of ozone has been characterized for many building materials; however, scant information is available on how diurnal variation of ambient ozone influences ozone reaction with indoor surfaces. The primary objective of this study is to investigate ozone-surface reactions in response to a diurnally varying ozone exposure for three common building materials: ceiling tile, painted drywall, and carpet tile. A secondary objective is to examine the effects of air temperature and humidity. A third goal is to explore how conditioning of materials in an occupied office building might influence subsequent ozone-surface reactions. Experiments were performed at bench-scale with inlet ozone concentrations varied to simulate daytime (ozone elevated) and nighttime (ozone-free in these experiments) periods. To simulate office conditions, experiments were conducted at two temperatures (22 °C and 28 °C) and three relative humidity values (25%, 50%, 75%). Effects of indoor surface exposures were examined by placing material samples in an occupied office and repeating bench-scale characterization after exposure periods of 1 and 2 months. Deposition velocities were observed to be highest during the initial hour of ozone exposure with slow decrease in the subsequent hours of simulated daytime conditions. Daily-average ozone reaction probabilities for fresh materials are in the respective ranges of (1.7-2.7) × 10-5, (2.8-4.7) × 10-5, and (3.0-4.5) × 10-5 for ceiling tile, painted drywall, and carpet tile. The reaction probability decreases by 7%-47% across the three test materials after two 8-h periods of ozone exposure. Measurements with the samples from an occupied office reveal that deposition velocity can decrease or increase with time

  9. Effect of climate change on surface ozone over North America, Europe, and East Asia

    NASA Astrophysics Data System (ADS)

    Schnell, Jordan L.; Prather, Michael J.; Josse, Beatrice; Naik, Vaishali; Horowitz, Larry W.; Zeng, Guang; Shindell, Drew T.; Faluvegi, Greg

    2016-04-01

    The effect of future climate change on surface ozone over North America, Europe, and East Asia is evaluated using present-day (2000s) and future (2100s) hourly surface ozone simulated by four global models. Future climate follows RCP8.5, while methane and anthropogenic ozone precursors are fixed at year 2000 levels. Climate change shifts the seasonal surface ozone peak to earlier in the year and increases the amplitude of the annual cycle. Increases in mean summertime and high-percentile ozone are generally found in polluted environments, while decreases are found in clean environments. We propose that climate change augments the efficiency of precursor emissions to generate surface ozone in polluted regions, thus reducing precursor export to neighboring downwind locations. Even with constant biogenic emissions, climate change causes the largest ozone increases at high percentiles. In most cases, air quality extreme episodes become larger and contain higher ozone levels relative to the rest of the distribution.

  10. Ozone enhances diesel exhaust particles (DEP)-induced interleukin-8 (IL-8) gene expression in human airway epithelial cells through activation of nuclear factors- kappaB (NF-kappaB) and IL-6 (NF-IL6).

    PubMed

    Kafoury, Ramzi M; Kelley, James

    2005-12-01

    Ozone, a highly reactive oxidant gas is a major component of photochemical smog. As an inhaled toxicant, ozone induces its adverse effects mainly on the lung. Inhalation of particulate matter has been reported to cause airway inflammation in humans and animals. Furthermore, epidemiological evidence has indicated that exposure to particulate matter (PM[2.5-10]), including diesel exhaust particles (DEP) has been correlated with increased acute and chronic respiratory morbidity and exacerbation of asthma. Previously, exposure to ozone or particulate matter and their effect on the lung have been addressed as separate environmental problems. Ozone and particulate matter may be chemically coupled in the ambient air. In the present study we determined whether ozone exposure enhances DEP effect on interleukin-8 (IL-8) gene expression in human airway epithelial cells. We report that ozone exposure (0.5 ppm x 1 hr) significantly increased DEP-induced IL-8 gene expression in A549 cells (117 +/- 19 pg/ml, n = 6, p < 0.05) as compared to cultures treated with DEP (100 microg/ml x 4 hr) alone (31 +/- 3 pg/ml, n = 6), or cultures exposed to purified air (24 +/- 6 pg/ml, n = 6). The increased DEP-induced IL-8 gene expression following ozone exposure was attributed to ozone-induced increase in the activity of the transcription factors NF-kappaB and NF-IL6. The results of the present study indicate that ozone exposure enhances the toxicity of DEP in human airway epithelial cells by augmenting IL-8 gene expression, a potent chemoattractant of neutrophils in the lung. PMID:16819095

  11. Src-Mediated EGF Receptor Activation Regulates Ozone-Induced Interleukin 8 Expression in Human Bronchial Epithelial Cells

    PubMed Central

    Wages, Phillip A.; Devlin, Robert B.; Diaz-Sanchez, David; Peden, David B.; Samet, James M.

    2014-01-01

    Background: Human exposure to ozone (O3) results in pulmonary function decrements and airway inflammation. The mechanisms underlying these adverse effects remain unclear. Epidermal growth factor receptor (EGFR) plays an important role in the pathogenesis of lung inflammation. Objective We examined the role of EGFR activation in O3-induced expression of the chemokine interleukin 8 (IL-8) in human bronchial epithelial cells (HBEC). Methods We detected phosphorylated EGFR using immunoblotting. EGFR dimerization was examined through cross-linking reaction and immunoblotting, and levels of IL-8 protein were measured using ELISA. Results Exposure to O3 (0.25–1.0 ppm) induced rapid and marked increase in EGFR phosphorylation at the autophosphorylation site Y1068 and the transphosphorylation site Y845, implicating the involvement of Src kinase. Further investigation showed that O3 stimulation induced phosphorylation of Src at Y416, indicative of Src activation. Pharmacological inhibition of Src kinase activity abrogated O3-induced EGFR phosphorylation at tyrosines 1068 and 845. Moreover, pretreatment of BEAS-2B cells with inhibitor of either EGFR or Src kinase activities significantly blocked O3-induced IL-8 expression. Conclusion Conclusion: O3 exposure increased IL-8 expression through Src-mediated EGFR transactivation in HBEC. Citation> Wu W, Wages PA, Devlin RB, Diaz-Sanchez D, Peden DB, Samet JM. 2015. Src-mediated EGF receptor activation regulates ozone-induced interleukin 8 expression in human bronchial epithelial cells. Environ Health Perspect 123:231–236; http://dx.doi.org/10.1289/ehp.1307379 PMID:25303742

  12. The effects of a roster schedule change from 8- to 12-hour shifts on health and safety in a mining operation.

    PubMed

    Baker, A; Heiler, K; Ferguson, S A

    2001-12-01

    The current study examined the impact on employee health and safety of changes to the roster system of an Australian coal mine. Absenteeism and incident frequency rate data were collected over a 33-month period that covered three different roster schedules, an 8-hour system, a 12-hour system and a 12-hour system incorporating unregulated overtime. The first change was implemented after consultation with the employee population, whereas the second was not. There were no significant negative effects of the 12-hour pattern, when compared to the 8-hour system. However, when unregulated and excessive overtime was introduced as part of the second round of changes, absenteeism rates were increased in one sector of the mine. The maintenance sector was subject to a significant increase in absenteeism rates, which may have been attributable to the excessive overtime required of the workers in that area. It is important that overtime be strictly monitored and that the employee population are involved in the process of roster change. PMID:14564860

  13. Understanding the effectiveness of precursor reductions in lowering 8-hr ozone concentrations--Part II. The eastern United States.

    PubMed

    Reynolds, Steven D; Blanchard, Charles L; Ziman, Stephen D

    2004-11-01

    Analyses of ozone (O3) measurements in conjunction with photochemical modeling were used to assess the feasibility of attaining the federal 8-hr O3 standard in the eastern United States. Various combinations of volatile organic compound (VOC) and oxides of nitrogen (NOx) emission reductions were effective in lowering modeled peak 1-hr O3 concentrations. VOC emissions reductions alone had only a modest impact on modeled peak 8-hr O3 concentrations. Anthropogenic NOx emissions reductions of 46-86% of 1996 base case values were needed to reach the level of the 8-hr standard in some areas. As NOx emissions are reduced, O3 production efficiency increases, which accounts for the less than proportional response of calculated 8-hr O3 levels. Such increases in O3 production efficiency also were noted in previous modeling work for central California. O3 production in some urban core areas, such as New York City and Chicago, IL, was found to be VOC-limited. In these areas, moderate NOx emissions reductions may be accompanied by increases in peak 8-hr O3 levels. The findings help to explain differences in historical trends in 1- and 8-hr O3 levels and have serious implications for the feasibility of attaining the 8-hr O3 standard in several areas of the eastern United States.

  14. Understanding the effectiveness of precursor reductions in lowering 8-hr ozone concentrations--Part II. The eastern United States.

    PubMed

    Reynolds, Steven D; Blanchard, Charles L; Ziman, Stephen D

    2004-11-01

    Analyses of ozone (O3) measurements in conjunction with photochemical modeling were used to assess the feasibility of attaining the federal 8-hr O3 standard in the eastern United States. Various combinations of volatile organic compound (VOC) and oxides of nitrogen (NOx) emission reductions were effective in lowering modeled peak 1-hr O3 concentrations. VOC emissions reductions alone had only a modest impact on modeled peak 8-hr O3 concentrations. Anthropogenic NOx emissions reductions of 46-86% of 1996 base case values were needed to reach the level of the 8-hr standard in some areas. As NOx emissions are reduced, O3 production efficiency increases, which accounts for the less than proportional response of calculated 8-hr O3 levels. Such increases in O3 production efficiency also were noted in previous modeling work for central California. O3 production in some urban core areas, such as New York City and Chicago, IL, was found to be VOC-limited. In these areas, moderate NOx emissions reductions may be accompanied by increases in peak 8-hr O3 levels. The findings help to explain differences in historical trends in 1- and 8-hr O3 levels and have serious implications for the feasibility of attaining the 8-hr O3 standard in several areas of the eastern United States. PMID:15587557

  15. Response of photosynthesis and cellular antioxidants to ozone in Populus leaves

    SciTech Connect

    Gupta, A.S.; Alscher, R.G. ); McCune, D. )

    1991-06-01

    Atmospheric ozone causes formation of various highly reactive intermediates (e.g. peroxyl and superoxide radicals, H{sub 2}O{sub 2}, etc.) in plant tissues. A plant's productivity in environments with ozone may be related to its ability to scavenge the free radicals formed. The effects of ozone on photosynthesis and some free radical scavengers were measured in the fifth emergent leaf of poplars. Clonal poplars (Populus deltoides {times} Populus cv caudina) were fumigated with 180 parts per billion ozone for 3 hours. Photosynthesis was measured before, during, and after fumigation. During the first 90 minutes of ozone exposure, photosynthetic rates were unaffected but gluthathione levels and superoxide dismutase activity increased. After 90 minutes of ozone exposure photosynthetic rates began to decline while glutathione and superoxide dismutase continued to increase. Total glutathione (reduced plus oxidized) increased in fumigated leaves throughout the exposure period. The ratio of GSH/GSSG also decreased from 12.8 to 1.2 in ozone exposed trees. Superoxide dismutase levels increased twofold in fumigated plants. After 4 hours of ozone exposure, the photosynthetic rate was approximately half that of controls while flutathione levels and superoxide dismutase activity remained above that of the controls. The elevated antioxidant levels were maintained 21 hours after ozone exposure while photosynthetic rates recovered to about 75% of that of controls. Electron transport and NADPH levels remained unaffected by the treatment. Hence, elevated antioxidant metabolism may protect the photosynthetic apparatus during exposure to ozone.

  16. Ozone-induced increases in substance P and 8-epi-prostaglandin F2 alpha in the airways of human subjects

    SciTech Connect

    Hazbun, M.E.; Hamilton, R.; Holian, A.; Eschenbacher, W.L. )

    1993-11-01

    We are interested in the mechanisms of ozone-induced lung effects after short-term exposure and the relationship with subsequent pulmonary inflammation and disease. Our hypothesis is that ozone, as a powerful oxidant, will diminish the activity of neutral endopeptidase (NEP) in the airways of humans with resulting increased concentrations of neuropeptides such as substance P (SP). We have exposed seven (two women, five men) healthy, nonsmoking individuals (22 to 30 yr of age) to filtered air and ozone (0.25 ppm) for 1 h in an environmental chamber during heavy exercise. Bronchoscopy with airway lavage (AL) and bronchoalveolar lavage (BAL) was performed immediately after ozone exposure. The lavage samples were analyzed by enzyme immunoassay for SP and 8-epi-prostaglandin F2 alpha (8-epi-PGF2 alpha) (a marker for oxidative free radical reaction) and by radioimmunoassay for complement fragments. FEV1 had declined 12.4 +/- 1.9% (mean +/- SEM) as a result of ozone exposure. The AL concentration for SP and 8-epi-PGF2 alpha and BAL concentration of C3a after ozone exposure were significantly higher than after the filtered air exposure (P < 0.05). There was a significant correlation between SP and 8-epi-PGF2 alpha concentrations in the AL fluid (r2 = 0.89 and P < 0.05). There were no changes in C5a in either compartment or any of the mediators in the plasma samples. These results extend previous results from animal studies suggesting that ozone's mechanism of action is through an oxidative reaction resulting in a decreased activity of NEP in the airways with a subsequent increase in the concentration and activity of SP.

  17. 76 FR 57871 - Approval of Air Quality Implementation Plans; California; South Coast; Attainment Plan for 1997 8...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-16

    ... Standards for Ozone,'' January 6, 2010 and 75 FR 2938 (January 19, 2010). In 1979, under section 109 of the...) for ozone at 0.12 parts per million (ppm) averaged over a 1-hour period. See 44 FR 8202 (February 8... level of ozone in the ambient air at 0.08 ppm, averaged over an 8-hour period. See 62 FR 38856 (July...

  18. The new system of shorter porcine oocyte in vitro maturation (18 hours) using ≥8 mm follicles derived from cumulus-oocyte complexes.

    PubMed

    Kwak, Seong-Sung; Yoon, Junchul David; Cheong, Seung-A; Jeon, Yubyeol; Lee, Eunsong; Hyun, Sang-Hwan

    2014-01-15

    Despite recent efforts to improve in vitro maturation (IVM) systems for porcine oocytes, developmental competence of in vitro-matured oocytes is still suboptimal compared with those matured in vivo. In this study, we compared oocytes obtained from large (≥8 mm; LF) and medium (3-7 mm; MF) sized follicles in terms of nuclear maturation, intracellular glutathione and reactive oxygen species levels, gene expression, and embryo developmental competence after IVM. In the control group, cumulus-oocyte complexes (COCs) were aspirated from MF and matured for 22 hours with hormones and subsequently matured for 18 to 20 hours without hormones at 39 °C, 5% CO2 in vitro. In the LF group, COCs were obtained from follicles larger than 8 mm and were subjected to IVM for only 18 hours. The ovaries have LF were averagely obtained with 1.7% per day during 2012 and it was significantly higher in the winter season. The results of the nuclear stage assessment of the COCs from the LFs are as follows: before IVM (0 hours); germinal vesicle stage (15.2%), metaphase I (MI) stage (55.4%), anaphase and telophase I stages (15.8%), and metaphase II (MII) stage (13.6%). After 6 hours IVM; germinal vesicle (4.2%), MI (43.6%), anaphase and telophase I (9.4%), and MII (42.8%). After 18-hour IVM; MI (9.7%) and MII (90.3%). Oocytes from LF showed a significant (P < 0.001) increase in intracellular glutathione (1.41 vs. 1.00) and decrease in reactive oxygen species (0.8 vs. 1.0) levels compared with the control. The cumulus cells derived from LFs showed lower (P < 0.1) mRNA expression of COX-2 and TNFAIP6, and higher (P < 0.1) mRNA expression of PCNA and Nrf2 compared with the control group-derived cumulus cells. After parthenogenetic activation, in vitro fertilization and somatic cell nuclear transfer (SCNT) using matured oocytes from LFs, the embryo development was significantly improved (greater blastocyst formation rates and total cell numbers in blastocysts) compared with the control group

  19. 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

  20. Ozone-initiated chemistry in an occupied simulated aircraft cabin.

    PubMed

    Weschler, Charles J; Wisthaler, Armin; Cowlin, Shannon; Tamás, Gyöngyi; Strøm-Tejsen, Peter; Hodgson, Alfred T; Destaillats, Hugo; Herrington, Jason; Zhang, Junfeng; Nazaroff, William W

    2007-09-01

    We have used multiple analytical methods to characterize the gas-phase products formed when ozone was added to cabin air during simulated 4-hour flights that were conducted in a reconstructed section of a B-767 aircraft containing human occupants. Two separate groups of 16 females were each exposed to four conditions: low air exchange (4.4 (h-1)), <2 ppb ozone; low air exchange, 61-64 ppb ozone; high air exchange (8.8 h(-1)), <2 ppb ozone; and high air exchange, 73-77 ppb ozone. The addition of ozone to the cabin air increased the levels of identified byproducts from approximately 70 to 130 ppb at the lower air exchange rate and from approximately 30 to 70 ppb at the higher air exchange rate. Most of the increase was attributable to acetone, nonanal, decanal, 4-oxopentanal (4-OPA), 6-methyl-5-hepten-2-one (6-MHO), formic acid, and acetic acid, with 0.25-0.30 mol of quantified product volatilized per mol of ozone consumed. Several of these compounds reached levels above their reported odor thresholds. Most byproducts were derived from surface reactions with occupants and their clothing, consistent with the inference that occupants were responsible for the removal of >55% of the ozone in the cabin. The observations made in this study have implications for other indoor settings. Whenever human beings and ozone are simultaneously present, one anticipates production of acetone, nonanal, decanal, 6-MHO, geranyl acetone, and 4-OPA.

  1. Microbiological evaluation of chicken carcasses in an immersion chilling system with water renewal at 8 and 16 hours.

    PubMed

    Souza, L C T; Pereira, J G; Spina, T L B; Izidoro, T B; Oliveira, A C; Pinto, J P A N

    2012-05-01

    Since 2004, Brazil has been the leading exporter of chicken. Because of the importance of this sector in the Brazilian economy, food safety must be ensured by control and monitoring of the production stages susceptible to contamination, such as the chilling process. The goal of this study was to evaluate changes in microbial levels on chicken carcasses and in chilling water after immersion in a chilling system for 8 and 16 h during commercial processing. An objective of the study was to encourage discussion regarding the Brazilian Ministry of Agriculture Livestock and Food Supply regulation that requires chicken processors to completely empty, clean, and disinfect each tank of the chilling system after every 8-h shift. Before and after immersion chilling, carcasses were collected and analyzed for mesophilic bacteria, Enterobacteriaceae, coliforms, and Escherichia coli. Samples of water from the chilling system were also analyzed for residual free chlorine. The results do not support required emptying of the chiller tank after 8 h; these tanks could be emptied after 16 h. The results for all carcasses tested at the 8- and 16-h time points indicated no significant differences in the microbiological indicators evaluated. These data provide both technical and scientific support for discussing changes in federal law regarding the management of immersion chilling water systems used as part of the poultry processing line.

  2. Microbiological evaluation of chicken carcasses in an immersion chilling system with water renewal at 8 and 16 hours.

    PubMed

    Souza, L C T; Pereira, J G; Spina, T L B; Izidoro, T B; Oliveira, A C; Pinto, J P A N

    2012-05-01

    Since 2004, Brazil has been the leading exporter of chicken. Because of the importance of this sector in the Brazilian economy, food safety must be ensured by control and monitoring of the production stages susceptible to contamination, such as the chilling process. The goal of this study was to evaluate changes in microbial levels on chicken carcasses and in chilling water after immersion in a chilling system for 8 and 16 h during commercial processing. An objective of the study was to encourage discussion regarding the Brazilian Ministry of Agriculture Livestock and Food Supply regulation that requires chicken processors to completely empty, clean, and disinfect each tank of the chilling system after every 8-h shift. Before and after immersion chilling, carcasses were collected and analyzed for mesophilic bacteria, Enterobacteriaceae, coliforms, and Escherichia coli. Samples of water from the chilling system were also analyzed for residual free chlorine. The results do not support required emptying of the chiller tank after 8 h; these tanks could be emptied after 16 h. The results for all carcasses tested at the 8- and 16-h time points indicated no significant differences in the microbiological indicators evaluated. These data provide both technical and scientific support for discussing changes in federal law regarding the management of immersion chilling water systems used as part of the poultry processing line. PMID:22564950

  3. Microbiology and evisceration efficiency of broiler carcasses slaughtered and held up to 8 hours postmortem prior to scalding and defeathering

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The implementation of on farm slaughter could eliminate potential animal welfare issues associated with cooping, transport, dumping, and shackling live broilers. This research evaluated evisceration efficiency and the microbiological implications of delaying scalding and defeathering for up to 8 h a...

  4. Occurrence of ozone as a phytotoxicant in Kiev, Ukraine and in the Ukrainian Carpathian mountains

    SciTech Connect

    Bytnerowicz, A.; Manning, W.; Blum, O.; Popovicheva, L.

    1995-12-31

    Ogawa passive ozone samplers were established at the Central Botanic Garden in Kiev and in five forest locations in the Ukrainian Carpathian mountains in summer, 1995. An active ozone monitor (Thermo-Electron 49) was also established at the Botanic Garden, together with plants of ozone-sensitive (Bel-W3) and ozone-tolerant (Bel-B) tobacco (Nicotiana tabacum). The highest average hourly ozone concentration monitored in Kiev was 84.4 ppb. From August to September, two-week average concentrations of ozone (Ogawa samplers) in the Carpathian forests ranged from 27.4--51.8 ppb. During a two-week exposure period, Bel-W3 tobacco plants in Kiev had foliar injury on leaf one as high as 62%, with only 13% for Bel-B. Ozone injury was found on a variety of indicator plants in Kiev and at three of the five passive sampler sites in the Carpathians.

  5. Comparison of Profile Total Ozone from SBUV (v8.6) with GOME-Type and Ground-Based Total Ozone for a 16-Year Period (1996 to 2011)

    NASA Technical Reports Server (NTRS)

    Chiou, E. W.; Bhartia, P. K.; McPeters, R. D.; Loyola, D. G.; Coldewey-Egbers, M.; Fioletov, V. E.; Van Roozendael, M.; Spurr, R.; Lerot, C.; Frith, S. M.

    2014-01-01

    This paper describes the comparison of the variability of total column ozone inferred from the three independent multi-year data records, namely, (i) Solar Backscatter Ultraviolet Instrument (SBUV) v8.6 profile total ozone, (ii) GTO (GOME-type total ozone), and (iii) ground-based total ozone data records covering the 16-year overlap period (March 1996 through June 2011). Analyses are conducted based on area-weighted zonal means for 0-30degS, 0-30degN, 50-30degS, and 30-60degN. It has been found that, on average, the differences in monthly zonal mean total ozone vary between -0.3 and 0.8% and are well within 1 %. For GTO minus SBUV, the standard deviations and ranges (maximum minus minimum) of the differences regarding monthly zonal mean total ozone vary between 0.6-0.7% and 2.8-3.8% respectively, depending on the latitude band. The corresponding standard deviations and ranges regarding the differences in monthly zonal mean anomalies show values between 0.4-0.6% and 2.2-3.5 %. The standard deviations and ranges of the differences ground-based minus SBUV regarding both monthly zonal means and anomalies are larger by a factor of 1.4-2.9 in comparison to GTO minus SBUV. The ground-based zonal means demonstrate larger scattering of monthly data compared to satellite-based records. The differences in the scattering are significantly reduced if seasonal zonal averages are analyzed. The trends of the differences GTO minus SBUV and ground-based minus SBUV are found to vary between -0.04 and 0.1%/yr (-0.1 and 0.3DU/yr). These negligibly small trends have provided strong evidence that there are no significant time-dependent differences among these multiyear total ozone data records. Analyses of the annual deviations from pre-1980 level indicate that, for the 15-year period of 1996 to 2010, all three data records show a gradual increase at 30-60degN from -5% in 1996 to -2% in 2010. In contrast, at 50-30degS and 30degS- 30degN there has been a leveling off in the 15 years after

  6. 78 FR 37122 - Approval and Promulgation of Implementation Plans; New York; Infrastructure SIP for the 1997 8...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-20

    ... the 1997 8-Hour Ozone and the 1997 and 2006 Fine Particulate Matter Standards AGENCY: Environmental...- hour ozone and the 1997 and 2006 fine particulate matter (PM 2.5 ) National Ambient Air Quality... statute. Certain other material, such as copyrighted material, is not placed on the Internet and will...

  7. An 8-hour system for Salmonella detection with immunomagnetic separation and homogeneous time-resolved fluorescence PCR.

    PubMed

    Hagren, Virve; von Lode, Piia; Syrjälä, Anniina; Korpimäki, Teemu; Tuomola, Mika; Kauko, Otto; Nurmi, Jussi

    2008-07-15

    We describe a system consisting of rapid sample enrichment and homogeneous end-point PCR analysis that enables the detection of Salmonella in various food matrices in 8 h. Sample preparation starts with 6 h enrichment step in supplemented broth, after which Salmonella cells are collected with immunomagnetic particles. The particles are washed and dispensed to ready-to-use PCR reaction vessels, which contain dried assay-specific reagents and an internal amplification control. PCR is performed with a novel instrument platform utilising the sensitive label technology of time-resolved fluorometry. Qualitative assay results are automatically interpreted and available in 45 min after sample addition. The overall accuracy, sensitivity and specificity of the Magda CA Salmonella system were 99.1%, 98.4% and 100.0%, respectively, based on the evaluation of 107 samples (beef, pork, poultry and ready-to-eat meals) artificially contaminated with sub-lethally injured Salmonella cells.

  8. Alteration in carboxyhemoglobin concentrations during exposure to 9 ppm carbon monoxide for 8 hours at sea level and 2134 m altitude in a hypobaric chamber

    SciTech Connect

    Horvath, S.M.; Bedi, J.F. )

    1989-10-01

    Seventeen non-smoking young men served as subjects to determine the alteration in carboxyhemoglobin (COHb) concentrations during exposure to 0 or 9 ppm carbon monoxide for 8 hours (CO) at sea level or an altitude of 2134 meters (7000 feet) in a hypobaric chamber. Nine subjects rested during the exposure and 8 exercised for 10 minutes of each exposure hour at a mean ventilation of 25 L (BTPS). All subjects performed a maximal aerobic capacity test at the completion of their respective exposures. Carboxyhemoglobin concentrations fell in all subjects during their exposures to 0 ppm CO at sea level or 2134 m. During the 8-h exposures to 9 ppm CO, COHb rose linearly from approximately 0.2 percent to 0.7 percent. No significant differences in uptake were found whether the subjects were resting or intermittently exercising during their 8-h exposures. COHb levels attained were similar at both sea level and 2134 m. Maximal aerobic capacity was reduced approximately 7-10 percent consequent to altitude exposure during 0 ppm CO exposures. These values were not altered following exposure for 8 h to 9 ppm CO in either the resting or exercising subjects.

  9. Characterizing the Vertical Processes of Ozone in Colorado's Front Range Using the GSFC Ozone DIAL

    NASA Astrophysics Data System (ADS)

    Sullivan, John T.; McGee, Thomas J.; Hoff, Raymond M.; Sumnicht, Grant; Twigg, Laurence

    2016-06-01

    Although characterizing the interactions of ozone throughout the entire troposphere are important for health and climate processes, there is a lack of routine measurements of vertical profiles within the United States. In order to monitor this lower ozone more effectively, the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center TROPospheric OZone DIfferential Absorption Lidar (GSFC TROPOZ DIAL) has been developed and validated within the Tropospheric Ozone Lidar Network (TOLNet). Two scientifically interesting ozone episodes are presented that were observed during the 2014 Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER AQ) campaign at Ft. Collins, Colorado. The first case study, occurring between 22-23 July 2014, indicates enhanced concentrations of ozone at Ft. Collins during nighttime hours, which was due to the complex recirculation of ozone within the foothills of the Rocky Mountain region. Although quantifying the ozone increase aloft during recirculation episodes has been historically difficult, results indicate that an increase of 20 - 30 ppbv of ozone at the Ft. Collins site has been attributed to this recirculation. The second case, occurring between Aug 4-8th 2014, characterizes a dynamical exchange of ozone between the stratosphere and the troposphere. This case, along with seasonal model parameters from previous years, is used to estimate the stratospheric contribution to the Rocky Mountain region. Results suggest that a large amount of stratospheric air is residing in the troposphere in the summertime near Ft. Collins, CO. The results also indicate that warmer tropopauses are correlated with an increase in stratospheric air below the tropopause in the Rocky Mountain Region.

  10. Simultaneous observations of SAO and QBO in winds, temperature and ozone in the tropical middle atmosphere over Thumba (8.5°N, 77°E)

    NASA Astrophysics Data System (ADS)

    Kumar, Karanam Kishore; Swain, Debadatta; John, Sherine Rachel; Ramkumar, Geetha

    2011-11-01

    Owing to the importance of middle atmosphere, recently, a Middle Atmospheric Dynamics (MIDAS) program was carried out during the period 2002-2007 at Thumba (8.5°N, 77°E). The measurements under this program, involving regular radiosonde/rocket flights as well as atmospheric radars, provided long period observations of winds and temperature in the middle atmospheric region from which waves and oscillations as well as their forcing mechanisms particularly in the low-latitude middle atmosphere could be analyzed. However, a detailed analysis of the forcing mechanisms remains incomplete due to the lack of important measurements like ozone which is a significant contributor to atmospheric dynamics. Presently, profiles of ozone are available from TIMED/SABER (Thermosphere, Ionosphere, Mesosphere Energetics and Dynamics/Sounding of the Atmosphere using Broad Emission Radiometry) satellite globally from about 15 to 100 km, over multiple years since 2002. In this regard, a comprehensive study has been carried out on ozone and its variability at Quasi Biennial Oscillation (QBO) and Semiannual Oscillation (SAO) scales using TIMED/SABER ozone observations during the MIDAS campaign period. Before using the TIMED/SABER ozone measurements, an inter-comparison has been carried out with in situ measurements of ozone obtained under the Southern Hemisphere Additional Ozonesondes (SHADOZ) campaign for the year 2007 at few stations. The inter-comparison showed very good agreement between SABER and ozonesonde derived ozone profiles. After validating the SABER observations, ozone profiles are used extensively to study the QBO and SAO along with temperature and winds in the 20-100 km height region. It is known that the SAO in mesosphere and stratosphere are in opposite phases, but the present study for the first time reports the aspect of opposite phases in the mesosphere itself. Thus, the present work attempts to study the long-period oscillations in stratosphere and mesosphere in ozone

  11. 78 FR 21296 - Approval and Promulgation of Implementation Plans; New Jersey; Infrastructure SIP for the 1997 8...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-10

    ... 18, 1997, EPA promulgated new and revised NAAQS for 8-hour ozone (62 FR 38856) and PM 2.5 (62 FR.... EPA strengthened the 24-hour PM 2.5 NAAQS from 65 g/m\\3\\ to 35 g/m\\3\\ on October 17, 2006 (71 FR 61144).\\2\\ \\1\\ EPA issued a revised 8-hour ozone standard on March 27, 2008 (73 FR 16436). On September...

  12. 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...

  13. Which metric of ambient ozone to predict daily mortality?

    NASA Astrophysics Data System (ADS)

    Moshammer, Hanns; Hutter, Hans-Peter; Kundi, Michael

    2013-02-01

    It is well known that ozone concentration is associated with daily cause specific mortality. But which ozone metric is the best predictor of the daily variability in mortality? We performed a time series analysis on daily deaths (all causes, respiratory and cardiovascular causes as well as death in elderly 65+) in Vienna for the years 1991-2009. We controlled for seasonal and long term trend, day of the week, temperature and humidity using the same basic model for all pollutant metrics. We found model fit was best for same day variability of ozone concentration (calculated as the difference between daily hourly maximum and minimum) and hourly maximum. Of these the variability displayed a more linear dose-response function. Maximum 8 h moving average and daily mean value performed not so well. Nitrogen dioxide (daily mean) in comparison performed better when previous day values were assessed. Same day ozone and previous day nitrogen dioxide effect estimates did not confound each other. Variability in daily ozone levels or peak ozone levels seem to be a better proxy of a complex reactive secondary pollutant mixture than daily average ozone levels in the Middle European setting. If this finding is confirmed this would have implications for the setting of legally binding limit values.

  14. Induction of stress proteins and MMP-9 by 0.8 ppm of ozone in murine skin.

    PubMed

    Valacchi, Giuseppe; Pagnin, Elisa; Okamoto, Tatsuya; Corbacho, Ana M; Olano, Estibaliz; Davis, Paul A; van der Vliet, Albert; Packer, Lester; Cross, Carroll E

    2003-06-01

    Ozone (O(3)) is among the most reactive environmental oxidant pollutants to which cutaneous tissues are exposed. O(3) exposure has been shown to induce antioxidant depletion as well as the oxidation of lipids and proteins within the outermost skin layer, the stratum corneum. However, relatively little is known regarding the potential effects of O(3) on the cellular constituents of the underlying skin epidermis and dermis. In the present study, hairless mice exposed for 6 h to 0.8 ppm O(3) showed increases in lipid peroxidation, as quantitated by increases in 4-hydroxynonenal-protein adducts. O(3) exposure caused an induction of the stress proteins HSP27 and heme oxygenase-1 (HO-1), starting at 6 h and increasing up to 18 h after O(3) exposure. This was accompanied by an increase in matrix metalloproteinase-9 (MMP-9) mRNA and activity levels, indicative of possible injurious-reparative processes. Collectively, our data demonstrate that skin exposure to O(3) not only affects antioxidant levels and oxidation markers in the outermost stratum corneum layer, but also induces cellular stress responses in the deeper cellular layers of the skin.

  15. Effect of photoperiodic pretreatments on symptom development in plants exposed to ozone

    SciTech Connect

    Godish, T.

    1980-01-01

    Results presented in this report on the effects of photoperiodic pretreatment on ozone sensitivity of plants are significantly different from the lone previous report on this subject. Juhren et al (5) studied the effects of photoperiodic pretreatments on sensitivity of pinto beans exposed to oxidants (presumably ozone). They reported that pinto bean plants were most sensitive to oxidants under short photoperiods (8 hours) and least sensitive to long photoperiods (16 hours). In studies of tomato and peas presented in this report, minimum sensitivity for tomato was observed under the 8 hour pretreatment; for peas minimum sensitivity was observed for the 8 and 10 hour pretreatments. Maximum sensitivity for tomato was observed for the 12-hour photoperiodic pretreatment; peas showed maximum sensitivity under the 14-hour photoperiod. 7 references, 1 table.

  16. New ozone standard in the U.S.A. applied to Mexico City metropolitan air quality

    SciTech Connect

    Bravo A, H. Sosa E, R.; Sanchez A, P.; Jaimes P, M.

    1998-12-31

    The air quality of the Mexico City Metropolitan Zone (MCMZ) is recognized as one of the worst air pollution problems in the world. At the present, ozone is the most critical atmospheric pollutant in the area. According to the air quality data of the monitoring station at the University of Mexico, the ozone problem started in 1986. Mexican Ozone Air Quality Standard (MOAQS) specifies that a concentration of 0.11 ppm must not be exceeded more than one hour a day, one day a year in the term of three years. The Official Air Quality Data (RAMA) from 19 monitoring stations in the MCMZ coincides with the University station`s data, presenting the same atmospheric pollution problem. In the most critical sites the MOAQS is exceeded more than 1,300 hours in a year. Now, the Environmental Protection Agency of the United States (EPA) is working to establish the new ozone standard. EPA is setting the standard at 0.08 ppm on an average of 8 hours, considering the 3 year average of the annual 4th highest daily maximum 8 hour ozone concentration. The purpose of this paper is to present the tendency and comparison between two standards (1 hour and 8 hours) of the ozone concentrations in the MCMZ, since 1986 to 1996. Although Mexico does not yet have the 8 hour standard for ozone, it is very important to analyze the existing air quality data with this new standard. In this way the aim is to protect the health of more than 20 million inhabitants in the MCMZ.

  17. 40 CFR 52.1779 - Control strategy: Ozone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-state Charlotte-Gastonia-Rockhill, North Carolina-South Carolina nonattainment area has attaining data for the 1997 8-hour ozone NAAQS. This determination, in accordance with 40 CFR 51.918, suspends the requirements for this area to submit an attainment demonstration, associated reasonably available...

  18. 40 CFR 52.582 - Control strategy: Ozone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... satisfies 40 CFR 58.20(f) which requires the State to provide for the establishment and maintenance of... area has attaining data for the 1997 8-hour ozone NAAQS. This determination, in accordance with 40 CFR... transportation control measures. (1) HOV Lane—This project referred to as AR 073B is the addition of HOV lanes...

  19. SRC-mediated EGF Receptor Activation Regulates Ozone-induced Interleukin 8 Expression in Human Bronchial Epithelial Cells

    EPA Science Inventory

    BACKGROUND: Human exposure to ozone (03) results in pulmonary function decrements and airway inflammation. The mechanisms underlying these adverse effects remain unclear. Epidermal growth factor receptor (EGFR) plays an important role in the pathogenesis of lung inflammation. ...

  20. Gridded global surface ozone metrics for atmospheric chemistry model evaluation

    NASA Astrophysics Data System (ADS)

    Sofen, E. D.; Bowdalo, D.; Evans, M. J.; Apadula, F.; Bonasoni, P.; Cupeiro, M.; Ellul, R.; Galbally, I. E.; Girgzdiene, R.; Luppo, S.; Mimouni, M.; Nahas, A. C.; Saliba, M.; Tørseth, K.

    2016-02-01

    The concentration of ozone at the Earth's surface is measured at many locations across the globe for the purposes of air quality monitoring and atmospheric chemistry research. We have brought together all publicly available surface ozone observations from online databases from the modern era to build a consistent data set for the evaluation of chemical transport and chemistry-climate (Earth System) models for projects such as the Chemistry-Climate Model Initiative and Aer-Chem-MIP. From a total data set of approximately 6600 sites and 500 million hourly observations from 1971-2015, approximately 2200 sites and 200 million hourly observations pass screening as high-quality sites in regionally representative locations that are appropriate for use in global model evaluation. There is generally good data volume since the start of air quality monitoring networks in 1990 through 2013. Ozone observations are biased heavily toward North America and Europe with sparse coverage over the rest of the globe. This data set is made available for the purposes of model evaluation as a set of gridded metrics intended to describe the distribution of ozone concentrations on monthly and annual timescales. Metrics include the moments of the distribution, percentiles, maximum daily 8-hour average (MDA8), sum of means over 35 ppb (daily maximum 8-h; SOMO35), accumulated ozone exposure above a threshold of 40 ppbv (AOT40), and metrics related to air quality regulatory thresholds. Gridded data sets are stored as netCDF-4 files and are available to download from the British Atmospheric Data Centre (doi: 10.5285/08fbe63d-fa6d-4a7a-b952-5932e3ab0452). We provide recommendations to the ozone measurement community regarding improving metadata reporting to simplify ongoing and future efforts in working with ozone data from disparate networks in a consistent manner.

  1. Ozone-induced alterations of lamellar body lipid and protein during alveolar injury and repair

    SciTech Connect

    Shelley, S.A.; Paciga, J.E.; Paterson, J.F.; Balis, J.U. )

    1989-09-01

    Alveolar Type II cells in the rat respond to severe, acute ozone injury (3 ppm ozone for eight hours) by increasing their intracellular pool of surfactant; however, the newly stored surfactant is abnormal in composition. Lamellar bodies isolated between 24 and 96 hours after ozone exposure contained significantly more cholesterol in relation to phosphatidylcholine than did controls. By contrast, the cholesterol content of surfactant isolated from alveolar lavage remained unchanged throughout an 8-day post-ozone period. The total protein content of lamellar bodies in relation to phosphatidylcholine was significantly decreased at 24 and 48 hours post-ozone. Analysis of lamellar body proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that the amount of a 14 kDa proteolipid was greatly reduced at the end of the eight-hour ozone exposure and remained low for at least 48 hours. This proteolipid appeared to be a specific lamellar body component since it was not detected in extracellular surfactant. The findings indicate that oxidative alveolar stress initiates characteristic alterations in both lipid and protein constituents of stored surfactant, without perturbation in the composition of extracellular surfactant.

  2. 40 CFR 52.1989 - Interstate Transport for the 1997 8-hour ozone NAAQS and 1997 PM2.5 NAAQS.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Act section 169A and 40 CFR 51.308(e) regarding Best Available Retrofit Technology and the requirements of 40 CFR 51.308(d)(2) and (d)(4)(v) regarding the calculation of baseline and natural conditions... National Park, Diamond Peak Wilderness Area, Three Sisters Wilderness Area, Strawberry Mountain...

  3. 40 CFR 52.1989 - Interstate Transport for the 1997 8-hour ozone NAAQS and 1997 PM2.5 NAAQS.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Act section 169A and 40 CFR 51.308(e) regarding Best Available Retrofit Technology and the requirements of 40 CFR 51.308(d)(2) and (d)(4)(v) regarding the calculation of baseline and natural conditions... National Park, Diamond Peak Wilderness Area, Three Sisters Wilderness Area, Strawberry Mountain...

  4. 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

    ... decimal place of the computed value is rounded, with values equal to or greater than 5 rounding up. Thus....089 0.086 0.084 0.080 1995 98% 0.087 0.085 0.083 0.080 0.075 Average 98% (2) As shown in example...

  5. 40 CFR 52.1989 - Interstate Transport for the 1997 8-hour ozone NAAQS and 1997 PM2.5 NAAQS.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Act section 169A and 40 CFR 51.308(e) regarding Best Available Retrofit Technology and the requirements of 40 CFR 51.308(d)(2) and (d)(4)(v) regarding the calculation of baseline and natural conditions for the Mt. Hood Wilderness Area, Mt. Jefferson Wilderness Area, Mt Washington Wilderness...

  6. AIRS Ozone Burden During Antarctic Winter: Time Series from 8/1/2005 to 9/30/2005

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] Click on the image for movie of AIRS Ozone Burden During Antarctic Winter

    AIRS provides a daily global 3-dimensional view of Earth's ozone layer. Since AIRS observes in the thermal infrared spectral range, it also allows scientists to view from space the Antarctic ozone hole for the first time continuously during polar winter. This image sequence captures the intensification of the annual ozone hole in the Antarctic Polar Vortex.

    The Atmospheric Infrared Sounder Experiment, with its visible, infrared, and microwave detectors, provides a three-dimensional look at Earth's weather. Working in tandem, the three instruments can make simultaneous observations all the way down to the Earth's surface, even in the presence of heavy clouds. With more than 2,000 channels sensing different regions of the atmosphere, the system creates a global, 3-D map of atmospheric temperature and humidity and provides information on clouds, greenhouse gases, and many other atmospheric phenomena. The AIRS Infrared Sounder Experiment flies onboard NASA's Aqua spacecraft and is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., under contract to NASA. JPL is a division of the California Institute of Technology in Pasadena.

  7. Ozone-Initiated Chemistry in an Occupied Simulated AircraftCabin

    SciTech Connect

    Weschler, C.J.; Wisthaler, A.; Cowlind, S.; Tamas, G.; Strom-Tejsena, P.; Hodgson, A.T.; Destaillats, H.; Herrington, J.; Zhang,J.; Nazaroff, W.W.

    2007-07-01

    We have used multiple analytical methods to characterize the gas-phase products formed when ozone was added to cabin air during simulated 4-hour flights that were conducted in a reconstructed section of a B-767 aircraft containing human occupants. Two separate groups of 16 females were each exposed to four conditions: low air exchange (4.4 h-1), <2 ppb ozone; low air exchange, 61-64 ppb ozone; high air exchange (8.8 h-1), <2 ppb ozone; and high air exchange, 73-77 ppb ozone. The addition of ozone to the cabin air increased the levels of identified byproducts from {approx}70 to 130 ppb at the lower air exchange rate and from {approx}30 to 70 ppb at the higher air exchange rate. Most of the increase was attributable to acetone, nonanal, decanal, 4-oxopentanal (4-OPA), 6-methyl-5-hepten-2-one (6-MHO), formic acid, and acetic acid, with 0.25-0.30 mol of quantified product volatilized per mol of ozone consumed. Several of these compounds reached levels above their reported odor thresholds. Most byproducts were derived from surface reactions with occupants and their clothing, consistent with the inference that occupants were responsible for the removal of >55% of the ozone in the cabin. The observations made in this study have implications for other indoor settings. Whenever human beings and ozone are simultaneously present, one anticipates production of acetone, nonanal, decanal, 6-MHO, geranyl acetone, and 4-OPA.

  8. Long-Term Exposure to Ozone and Life Expectancy in the United States, 2002 to 2008.

    PubMed

    Li, Chaoyang; Balluz, Lina S; Vaidyanathan, Ambarish; Wen, Xiao-Jun; Hao, Yongping; Qualters, Judith R

    2016-02-01

    Long-term exposure to ground-level ozone is associated with increased risk of morbidity and mortality. The association remains uncertain between long-term exposure to ozone and life expectancy. We assessed the associations between seasonal mean daily 8-hour maximum (8-hr max) ozone concentrations measured during the ozone monitoring seasons and life expectancy at birth in 3109 counties of the conterminous U.S. during 2002 to 2008. We used latent class growth analysis to identify latent classes of counties that had distinct mean levels and rates of change in ozone concentrations over the 7-year period and used linear regression analysis to determine differences in life expectancy by ozone levels. We identified 3 classes of counties with distinct seasonal mean daily 8-hr max ozone concentrations and rates of change. When compared with the counties with the lowest ozone concentrations, the counties with the highest ozone concentrations had 1.7- and 1.4-year lower mean life expectancy in males and females (both P < 0.0001), respectively. The associations remained statistically significant after controlling for potential confounding effects of seasonal mean PM2.5 concentrations and other selected environmental, demographic, socio-economic, and health-related factors (both P < 0.0001). A 5 ppb higher ozone concentration was associated with 0.25 year lower life expectancy in males (95% CI: -0.30 to -0.19) and 0.21 year in females (95% CI: -0.25 to -0.17). We identified 3 classes of counties with distinct mean levels and rates of change in ozone concentrations. Our findings suggest that long-term exposure to a higher ozone concentration may be associated with a lower life expectancy.

  9. Long-Term Exposure to Ozone and Life Expectancy in the United States, 2002 to 2008

    PubMed Central

    Li, Chaoyang; Balluz, Lina S.; Vaidyanathan, Ambarish; Wen, Xiao-Jun; Hao, Yongping; Qualters, Judith R.

    2016-01-01

    Abstract Long-term exposure to ground-level ozone is associated with increased risk of morbidity and mortality. The association remains uncertain between long-term exposure to ozone and life expectancy. We assessed the associations between seasonal mean daily 8-hour maximum (8-hr max) ozone concentrations measured during the ozone monitoring seasons and life expectancy at birth in 3109 counties of the conterminous U.S. during 2002 to 2008. We used latent class growth analysis to identify latent classes of counties that had distinct mean levels and rates of change in ozone concentrations over the 7-year period and used linear regression analysis to determine differences in life expectancy by ozone levels. We identified 3 classes of counties with distinct seasonal mean daily 8-hr max ozone concentrations and rates of change. When compared with the counties with the lowest ozone concentrations, the counties with the highest ozone concentrations had 1.7- and 1.4-year lower mean life expectancy in males and females (both P < 0.0001), respectively. The associations remained statistically significant after controlling for potential confounding effects of seasonal mean PM2.5 concentrations and other selected environmental, demographic, socio-economic, and health-related factors (both P < 0.0001). A 5 ppb higher ozone concentration was associated with 0.25 year lower life expectancy in males (95% CI: −0.30 to −0.19) and 0.21 year in females (95% CI: −0.25 to −0.17). We identified 3 classes of counties with distinct mean levels and rates of change in ozone concentrations. Our findings suggest that long-term exposure to a higher ozone concentration may be associated with a lower life expectancy. PMID:26886595

  10. Long-Term Exposure to Ozone and Life Expectancy in the United States, 2002 to 2008.

    PubMed

    Li, Chaoyang; Balluz, Lina S; Vaidyanathan, Ambarish; Wen, Xiao-Jun; Hao, Yongping; Qualters, Judith R

    2016-02-01

    Long-term exposure to ground-level ozone is associated with increased risk of morbidity and mortality. The association remains uncertain between long-term exposure to ozone and life expectancy. We assessed the associations between seasonal mean daily 8-hour maximum (8-hr max) ozone concentrations measured during the ozone monitoring seasons and life expectancy at birth in 3109 counties of the conterminous U.S. during 2002 to 2008. We used latent class growth analysis to identify latent classes of counties that had distinct mean levels and rates of change in ozone concentrations over the 7-year period and used linear regression analysis to determine differences in life expectancy by ozone levels. We identified 3 classes of counties with distinct seasonal mean daily 8-hr max ozone concentrations and rates of change. When compared with the counties with the lowest ozone concentrations, the counties with the highest ozone concentrations had 1.7- and 1.4-year lower mean life expectancy in males and females (both P < 0.0001), respectively. The associations remained statistically significant after controlling for potential confounding effects of seasonal mean PM2.5 concentrations and other selected environmental, demographic, socio-economic, and health-related factors (both P < 0.0001). A 5 ppb higher ozone concentration was associated with 0.25 year lower life expectancy in males (95% CI: -0.30 to -0.19) and 0.21 year in females (95% CI: -0.25 to -0.17). We identified 3 classes of counties with distinct mean levels and rates of change in ozone concentrations. Our findings suggest that long-term exposure to a higher ozone concentration may be associated with a lower life expectancy. PMID:26886595

  11. Fabrication of a SU-8-based polymer-enclosed channel with a penetrating UV/ozone-modified interior surface for electrokinetic separation of proteins

    NASA Astrophysics Data System (ADS)

    Chang, Chia-Jung; Yang, Chung-Shi; Lan, Li-Hua; Wang, Pen-Cheng; Tseng, Fan-Gang

    2010-11-01

    This paper introduces electrokinetic separation inside fully cross-linked epoxy-based polymer channels that were batch modified on the inner surfaces using a penetrating UV/ozone treatment from the outside. The treatment can employ either a 254 nm UV source in an ozone-rich environment or a stand-alone 172 nm UV source to directly generate C=O hydrophilic functional groups on the embedded polymer channel wall surfaces. Short-wavelength UV radiation was employed to break polymer surface bonds inside the channel. Ozone generated directly from air or supplied externally oxidized the reaction site on the activated polymer surface to generate the desired functional groups. An epoxy-based photoresist compound, SU-8 (MicroChem, MA), which is widely used in microfluidic systems, was employed to demonstrate the surface modification. Fourier transform infrared spectroscopy (FTIR) and high resolution x-ray photoelectron spectroscopy (HRXPS) were employed to characterize the functional groups that formed after the UV/ozone surface modification and to confirm the formation of O-H functional groups from the phenol group covalently bonded to the SU-8 surface, attributed mostly to the surface hydrophilicity modification. Water contact angles on the modified surface ranged from 72° to 12° depending on the processing time, UV power and ozone concentration. These angles were retained for at least 4 weeks after the process. Finally, the inner wall surfaces of the SU-8-enclosed channels were successfully modified using this technology, and rapid water transportation and EOF pumping were visualized inside the channel after surface modification. Successful electrokinetic separation of 10 mM BSA and 10 mM anti-rabbit IgG labeled with FITC inside the channel was also carried out. The polymer channel revealed a surface charge density of 75% of the zeta potential on a microslide glass surface, indicating the potential for molecule separation using polymer channels instead of glass channels

  12. Evaluation of microporous carbon filters as catalysts for ozone decomposition

    SciTech Connect

    Whinnery, L.; Coutts, D.; Shen, C.; Adams, R.; Quintana, C.; Showalter, S.

    1994-12-31

    Ozone is produced in small quantities in photocopiers and laser printers in the workplace and large quantities in industrial waste water treatment facilities. Carbon filters are commonly used to decompose this unwanted ozone. The three most important factors in producing a filter for this purpose are flow properties, efficiency, and cost. Most ozone decomposition applications require very low back-pressure at modest flow rates. The tradeoff between the number of pores and the size of the pores will be discussed. Typical unfiltered emissions in the workplace are approximately 1 ppm. The maximum permissible exposure limit, PEL, for worker exposure to ozone is 0.1 ppm over 8 hours. Several methods have been examined to increase the efficiency of ozone decomposition. Carbon surfaces were modified with catalysts, the surface activated, and the surface area was increased, in attempts to decompose ozone more effectively. Methods to reduce both the processing and raw material costs were investigated. Several sources of microporous carbon were investigated as ozone decomposition catalysts. Cheaper processing routes including macropore templating, faster drying and extracting methods were also studied.

  13. Synoptic and meteorological drivers of extreme ozone concentrations over Europe

    NASA Astrophysics Data System (ADS)

    Otero, Noelia Felipe; Sillmann, Jana; Schnell, Jordan L.; Rust, Henning W.; Butler, Tim

    2016-04-01

    The present work assesses the relationship between local and synoptic meteorological conditions and surface ozone concentration over Europe in spring and summer months, during the period 1998-2012 using a new interpolated data set of observed surface ozone concentrations over the European domain. Along with local meteorological conditions, the influence of large-scale atmospheric circulation on surface ozone is addressed through a set of airflow indices computed with a novel implementation of a grid-by-grid weather type classification across Europe. Drivers of surface ozone over the full distribution of maximum daily 8-hour average values are investigated, along with drivers of the extreme high percentiles and exceedances or air quality guideline thresholds. Three different regression techniques are applied: multiple linear regression to assess the drivers of maximum daily ozone, logistic regression to assess the probability of threshold exceedances and quantile regression to estimate the meteorological influence on extreme values, as represented by the 95th percentile. The relative importance of the input parameters (predictors) is assessed by a backward stepwise regression procedure that allows the identification of the most important predictors in each model. Spatial patterns of model performance exhibit distinct variations between regions. The inclusion of the ozone persistence is particularly relevant over Southern Europe. In general, the best model performance is found over Central Europe, where the maximum temperature plays an important role as a driver of maximum daily ozone as well as its extreme values, especially during warmer months.

  14. Real-Time Science on Social Media: The Example of Twitter in the Minutes, Hours, Days after the 2015 M7.8 Nepal Earthquake

    NASA Astrophysics Data System (ADS)

    Lomax, A.; Bossu, R.; Mazet-Roux, G.

    2015-12-01

    Scientific information on disasters such as earthquakes typically comes firstly from official organizations, news reports and interviews with experts, and later from scientific presentations and peer-reviewed articles. With the advent of the Internet and social media, this information is available in real-time from automated systems and within a dynamic, collaborative interaction between scientific experts, responders and the public. After the 2015 M7.8 Nepal earthquake, Twitter Tweets from earth scientists* included information, analysis, commentary and discussion on earthquake parameters (location, size, mechanism, rupture extent, high-frequency radiation, …), earthquake effects (distribution of felt shaking and damage, triggered seismicity, landslides, …), earthquake rumors (e.g. the imminence of a larger event) and other earthquake information and observations (aftershock forecasts, statistics and maps, source and regional tectonics, seismograms, GPS, InSAR, photos/videos, …).In the future (while taking into account security, false or erroneous information and identity verification), collaborative, real-time science on social media after a disaster will give earlier and better scientific understanding and dissemination of public information, and enable improved emergency response and disaster management.* A sample of scientific Tweets after the 2015 Nepal earthquake: In the first minutes: "mb5.9 Mwp7.4 earthquake Nepal 2015.04.25-06:11:25UTC", "Major earthquake shakes Nepal 8 min ago", "Epicenter between Pokhara and Kathmandu", "Major earthquake shakes Nepal 18 min ago. Effects derived from witnesses' reports". In the first hour: "shallow thrust faulting to North under Himalayas", "a very large and shallow event ... Mw7.6-7.7", "aftershocks extend east and south of Kathmandu, so likely ruptured beneath city", "Valley-blocking landslides must be a very real worry". In the first day: "M7.8 earthquake in Nepal 2hr ago: destructive in Kathmandu Valley and

  15. Effects of Ozone and Peroxyacetyl Nitrate on Polar Lipids and Fatty Acids in Leaves of Morning Glory and Kidney Bean

    PubMed Central

    Nouchi, Isamu; Toyama, Susumu

    1988-01-01

    To compare the effects of ozone and peroxyacetyl nitrate (PAN) on leaf lipids, fatty acids and malondialdehyde (MDA), morning glory (Pharbitis nil Choisy cv Scarlet O'Hara) and kidney bean (Phaseolus vulgaris L. cv Gintebo) plants were exposed to either ozone (0.15 microliter per liter for 8 hours) or PAN (0.10 microliter per liter for up to 8 hours). Ozone increased phospholipids in morning glory and decreased in kidney bean at the initial stage (2-4 hours) of exposure, while it scarcely changed glycolipids, the unsaturated fatty acids, and MDA in both plants. A large reduction of glycolipids occurred 1 day after ozone exposure in both plants. PAN caused marked drops in phospholipids and glycolipids in kidney bean at relatively late stage (6-8 hours) of exposure, while it increased phosphatidic acid and decreased the unsaturated fatty acids, an increase which was accompanied by a large increase in MDA. These results suggest that ozone may not directly oxidize unsaturated fatty acids at the initial stage of exposure, but may alter polar lipid metabolism, particularly phospholipids. On the other hand, PAN may abruptly and considerably degrade phospholipids and glycolipids by peroxidation or hydrolysis at the late stage of exposure. The present study shows that ozone and PAN affect polar lipids in different manners. Images Fig. 2 Fig. 3 PMID:16666199

  16. Contributors to ozone episodes in three US/Mexico border twin-cities.

    PubMed

    Shi, Chune; Fernando, H J S; Yang, Jie

    2009-09-01

    The Process Analysis tools of the Community Multiscale Air Quality (CMAQ) modeling system together with back-trajectory analysis were used to assess potential contributors to ozone episodes that occurred during June 1-4, 2006, in three populated U.S.-Mexico border twin cities: San Diego/Tijuana, Imperial/Mexicali and El Paso/Ciudad Juárez. Validation of CMAQ output against surface ozone measurements indicates that the predictions are acceptable with regard to commonly recommended statistical standards and comparable to other reported studies. The mean normalized bias test (MNBT) and mean normalized gross error (MNGE) for hourly ozone fall well within the US EPA suggested range of +/-15% and 35%, respectively, except MNBT for El Paso. The MNBTs for maximum 8-h average ozone are larger than those for hourly ozone, but all the simulated maximum 8-h average ozone are within a factor of 2 of those measured in all three regions. The process and back-trajectory analyses indicate that the main sources of daytime ground-level ozone are the local photochemical production and regional transport. By integrating the effects of each process over the depth of the daytime planetary boundary layer (PBL), it is found that in the San Diego area (SD), chemistry and vertical advection contributed about 36%/48% and 64%/52% for June 2 and 3, respectively. This confirms the previous finding that high-altitude regional transport followed by fumigation contributes significantly to ozone in SD. The back-trajectory analysis shows that this ozone was mostly transported from the coastal area of southern California. For the episodes in Imperial Valley and El Paso, respectively, ozone was transported from the coastal areas of southern California and Mexico and from northern Texas and Oklahoma.

  17. Contributors to ozone episodes in three US/Mexico border twin-cities.

    PubMed

    Shi, Chune; Fernando, H J S; Yang, Jie

    2009-09-01

    The Process Analysis tools of the Community Multiscale Air Quality (CMAQ) modeling system together with back-trajectory analysis were used to assess potential contributors to ozone episodes that occurred during June 1-4, 2006, in three populated U.S.-Mexico border twin cities: San Diego/Tijuana, Imperial/Mexicali and El Paso/Ciudad Juárez. Validation of CMAQ output against surface ozone measurements indicates that the predictions are acceptable with regard to commonly recommended statistical standards and comparable to other reported studies. The mean normalized bias test (MNBT) and mean normalized gross error (MNGE) for hourly ozone fall well within the US EPA suggested range of +/-15% and 35%, respectively, except MNBT for El Paso. The MNBTs for maximum 8-h average ozone are larger than those for hourly ozone, but all the simulated maximum 8-h average ozone are within a factor of 2 of those measured in all three regions. The process and back-trajectory analyses indicate that the main sources of daytime ground-level ozone are the local photochemical production and regional transport. By integrating the effects of each process over the depth of the daytime planetary boundary layer (PBL), it is found that in the San Diego area (SD), chemistry and vertical advection contributed about 36%/48% and 64%/52% for June 2 and 3, respectively. This confirms the previous finding that high-altitude regional transport followed by fumigation contributes significantly to ozone in SD. The back-trajectory analysis shows that this ozone was mostly transported from the coastal area of southern California. For the episodes in Imperial Valley and El Paso, respectively, ozone was transported from the coastal areas of southern California and Mexico and from northern Texas and Oklahoma. PMID:19559465

  18. 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

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

    SciTech Connect

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

    1993-09-01

    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.

  20. The chemistry and diffusion of aircraft exhausts in the lower stratosphere during the first few hours after fly-by. [with attention to ozone depletion by SST exhaust plumes

    NASA Technical Reports Server (NTRS)

    Hilst, G. R.

    1974-01-01

    An analysis of the hydrogen-nitrogen-oxygen reaction systems in the lower stratosphere as they are initially perturbed by individual aircraft engine exhaust plumes was conducted in order to determine whether any significant chemical reactions occur, either among exhaust chemical species, or between these species and the environmental ozone, while the exhaust products are confined to intact plume segments at relatively high concentrations. The joint effects of diffusive mixing and chemical kinetics on the reactions were also studied, using the techniques of second-order closure diffusion/chemistry models. The focus of the study was on the larger problem of the potential depletion of ozone by supersonic transport aircraft exhaust materials emitted into the lower stratosphere.

  1. 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.

  2. Tropospheric ozone in the vicinity of the ozone hole - 1987 Airborne Antarctic Ozone Experiment

    NASA Technical Reports Server (NTRS)

    Gregory, Gerald L.; Warren, Linda S.; Hypes, Warren D.; Tuck, Adrian F.; Kelly, Kenneth K.; Krueger, Arlin J.

    1989-01-01

    Results are presented on ozone measurements in the upper troposphere/lower stratosphere over Antarctica, obtained by NASA DC-8 aircraft during the August/September 1987 Airborne Antarctic Ozone Experiment. The ozone mixing ratios as high as several hundred ppbv were measured, but in all cases these ratios were observed in pockets of upper atmospheric air, both in the vicinity of and away from the location of the ozone hole. The background ozone values in the surrounding troposphere were typically in the range of 20-50 ppbv. Correlation of tropospheric ozone observations with the boundaries of the ozone hole differed in the course of the experiment. During the August 28 - September 2 flights, encounters with ozone-rich air were limited, and the background tropospheric ozone appeared to decrease beneath the hole. For the later flights, and as the ozone hole deepened, the ozone-rich air was frequently observed in the vicinity of the hole, and the average ozone values at the flight altitude were frequently higher than the background values.

  3. Contribution of ozone to airborne aldehyde formation in Paris homes.

    PubMed

    Rancière, Fanny; Dassonville, Claire; Roda, Célina; Laurent, Anne-Marie; Le Moullec, Yvon; Momas, Isabelle

    2011-09-15

    Indoor aldehydes may result from ozone-initiated chemistry, mainly documented by experimental studies. As part of an environmental investigation included in the PARIS birth cohort, the aim of this study was to examine ozone contribution to airborne aldehyde formation in Paris homes. Formaldehyde, acetaldehyde and hexaldehyde levels, as well as styrene, nitrogen dioxide and nicotine concentrations, comfort parameters and carbon dioxide levels, were measured twice during the first year of life of the babies. Ambient ozone concentrations were collected from the closest background station of the regional air monitoring network. Traffic-related nitrogen oxide concentrations in front of the dwellings were estimated by an air pollution dispersion model. Home characteristics and families' way of life were described by questionnaires. Stepwise multiple linear regression models were used to link aldehyde levels with ambient ozone concentrations and a few aldehyde precursors involved in oxidation reactions, adjusting for other indoor aldehyde sources, comfort parameters and traffic-related nitrogen oxides. A 4 and 11% increase in formaldehyde and hexaldehyde levels was pointed out when 8-hour ozone concentrations increased by 20 μg/m(3). The influence of potential precursors such as indoor styrene level and frequent use of air fresheners, containing unsaturated volatile organic compounds as terpenes, was also found. Thus, our results suggest that ambient ozone can significantly impact indoor air quality, especially with regard to formaldehyde and hexaldehyde levels.

  4. 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

    ... attainment of the 1997 8-hour ozone NAAQS during this monitoring period. See 77 FR 36163, 77 FR 47533, 77 FR 17341, and 74 FR 63993. EPA is aware that preliminary ambient air quality monitoring data for 2012 may... moderate nonattainment areas. On December 11, 2012 (77 FR 73570), EPA published a notice of...

  5. 78 FR 21302 - Approval and Promulgation of Implementation Plans; New York State Ozone Implementation Plan Revision

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-10

    ... outdoors, and individuals with a pre-existing respiratory disease, such as asthma. On April 30, 2004 (69 FR... a requirement to submit a demonstration of attainment. EPA notes that on December 7, 2009 (74 FR..., 2008 (73 FR 15672) EPA determined that Jefferson County attained the 8-hour ozone standard. On June...

  6. 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

    ... individuals with a pre-existing respiratory disease, such as asthma. On April 30, 2004 (69 FR 23858), EPA... Poughkeepsie nonattainment area is composed of Dutchess, Orange and Putnam counties. On December 7, 2009 (74 FR 63993), EPA determined that the Poughkeepsie area attained the 8-hour ozone standard and on March...

  7. 77 FR 26950 - Designation of Areas for Air Quality Planning Purposes; California; Western Mojave Desert Ozone...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-08

    ...'' nonattainment for the 1997 8-hour ozone NAAQS.\\1\\ See 69 FR 23858, at 23884 (April 30, 2004) and 40 CFR 81.305... FR 29073, May 20, 2008), and reclassified the Sacramento Metro area from ``Serious'' to ``Severe-15'' nonattainment effective June 4, 2010 (75 FR 24409, May 5, 2010). \\3\\ CARB subsequently submitted a SIP...

  8. 78 FR 7672 - Approval and Promulgation of Implementation Plans; Texas; Beaumont/Port Arthur Ozone Maintenance...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-04

    ... Vehicle Emissions Simulator (MOVES) 2010a emissions model. The BPA 1997 8-hour ozone maintenance area... index, some information is not publicly available, e.g., Confidential Business Information or other... at the Air Planning Section (6PD-L), Environmental Protection Agency, 1445 Ross Avenue, Suite...

  9. Improved Space-Time Forecasting of next Day Ozone Concentrations in the Eastern U.S.

    EPA Science Inventory

    There is an urgent need to provide accurate air quality information and forecasts to the general public and environmental health decision-makers. This paper develops a hierarchical space-time model for daily 8-hour maximum ozone concentration (O3) data covering much of the easter...

  10. 76 FR 48207 - Federal Implementation Plans: Interstate Transport of Fine Particulate Matter and Ozone and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-08

    ... FIP Federal Implementation Plan FR Federal Register EPA U.S. Environmental Protection Agency GHG... proposed revisions to the 8-hour ozone NAAQS that the Agency had issued March 12, 2008 (75 FR 2938); the... the District of Columbia Circuit (``Court'') in 2008. CAIR, promulgated May 12, 2005 (70 FR...

  11. Ozone and ozone byproducts in the cabins of commercial aircraft.

    PubMed

    Weisel, Clifford; Weschler, Charles J; Mohan, Kris; Vallarino, Jose; Spengler, John D

    2013-05-01

    The aircraft cabin represents a unique indoor environment due to its high surface-to-volume ratio, high occupant density, and the potential for high ozone concentrations at cruising altitudes. Ozone was continuously measured and air was sampled on sorbent traps, targeting carbonyl compounds, on 52 transcontinental U.S. or international flights between 2008 and 2010. The sampling was predominantly on planes that did not have ozone scrubbers (catalytic converters). Peak ozone levels on aircraft without catalytic convertors exceeded 100 ppb, with some flights having periods of more than an hour when the ozone levels were >75 ppb. Ozone was greatly reduced on relatively new aircraft with catalytic convertors, but ozone levels on two flights whose aircraft had older convertors were similar to those on planes without catalytic convertors. Hexanal, heptanal, octanal, nonanal, decanal, and 6-methyl-5-hepten-2-one (6-MHO) were detected in the aircraft cabin at sub- to low ppb levels. Linear regression models that included the log transformed mean ozone concentration, percent occupancy, and plane type were statistically significant and explained between 18 and 25% of the variance in the mixing ratio of these carbonyls. Occupancy was also a significant factor for 6-MHO, but not the linear aldehydes, consistent with 6-MHO's formation from the reaction between ozone and squalene, which is present in human skin oils. PMID:23517299

  12. Gridded global surface ozone metrics for atmospheric chemistry model evaluation

    NASA Astrophysics Data System (ADS)

    Sofen, E. D.; Bowdalo, D.; Evans, M. J.; Apadula, F.; Bonasoni, P.; Cupeiro, M.; Ellul, R.; Galbally, I. E.; Girgzdiene, R.; Luppo, S.; Mimouni, M.; Nahas, A. C.; Saliba, M.; Tørseth, K.; Wmo Gaw, Epa Aqs, Epa Castnet, Capmon, Naps, Airbase, Emep, Eanet Ozone Datasets, All Other Contributors To

    2015-07-01

    The concentration of ozone at the Earth's surface is measured at many locations across the globe for the purposes of air quality monitoring and atmospheric chemistry research. We have brought together all publicly available surface ozone observations from online databases from the modern era to build a consistent dataset for the evaluation of chemical transport and chemistry-climate (Earth System) models for projects such as the Chemistry-Climate Model Initiative and Aer-Chem-MIP. From a total dataset of approximately 6600 sites and 500 million hourly observations from 1971-2015, approximately 2200 sites and 200 million hourly observations pass screening as high-quality sites in regional background locations that are appropriate for use in global model evaluation. There is generally good data volume since the start of air quality monitoring networks in 1990 through 2013. Ozone observations are biased heavily toward North America and Europe with sparse coverage over the rest of the globe. This dataset is made available for the purposes of model evaluation as a set of gridded metrics intended to describe the distribution of ozone concentrations on monthly and annual timescales. Metrics include the moments of the distribution, percentiles, maximum daily eight-hour average (MDA8), SOMO35, AOT40, and metrics related to air quality regulatory thresholds. Gridded datasets are stored as netCDF-4 files and are available to download from the British Atmospheric Data Centre (doi:10.5285/08fbe63d-fa6d-4a7a-b952-5932e3ab0452). We provide recommendations to the ozone measurement community regarding improving metadata reporting to simplify ongoing and future efforts in working with ozone data from disparate networks in a consistent manner.

  13. Quantifying the spatial distribution of surface ozone concentration in the UK

    NASA Astrophysics Data System (ADS)

    Coyle, M.; Smith, R. I.; Stedman, J. R.; Weston, K. J.; Fowler, D.

    A study of ozone concentration measurements at 20 rural sites throughout the UK has enabled the identification of the major variables controlling surface ozone concentrations (wind velocity, topography and local NO sources). Empirical methods to quantify the spatial pattern in surface concentrations at 1 km resolution, incorporating these influences, are developed. The procedure maps ozone concentrations from the period of the day when measurements are representative of large areas of countryside. In these conditions, rural monitoring sites (˜100 km apart) are highly correlated ( r2⩾0.8) and least affected by local site characteristics. The effects of boundary layer stability are quantified using the observed relationship between the diurnal variability of surface ozone concentration and altitude. This allows the detailed structure in rural concentrations to be quantified. An urban correction, to account for the gas phase titration of surface ozone by local NO sources, is added to the mapping procedure based on the relationship between urban ozone concentration measurements and those in rural areas. The spatial distribution of the annual average ozone concentration and the accumulated ozone concentration over a threshold of 40 ppb (AOT40) are calculated from UK measurements. Simple assessments of the effects of ozone on materials and vegetation are made. Although 87% of the UK exceeds the critical level for materials (20 ppb annual average), this is less than 0.1% of urban areas and so the risk of damage is probably small. For crops and semi-natural vegetation, the critical level (AOT40 3000 ppb h May-July daylight hours) is exceeded over 71% of the UK; for forests, the critical level (10,000 ppb h April-September daylight hours) is exceeded over 8% of the country. This indicates the potential for effects on large areas of crops and semi-natural vegetation but only small areas of forest.

  14. Diagnosis of Photochemical Ozone Production Rates and Limiting Factors based on Observation-based Modeling Approach over East Asia: Impact of Radical Chemistry Mechanism and Ozone-Control Implications

    NASA Astrophysics Data System (ADS)

    Kanaya, Y.

    2015-12-01

    Growth of tropospheric ozone, causing health and climate impacts, is concerned over East Asia, because emissions of precursors have dramatically increased. Photochemical production rates of ozone and limiting factors, primarily studied for urban locations, have been poorly assessed within a perspective of regional-scale air pollution over East Asia. We performed comprehensive observations of ozone precursors at several locations with regional representativeness and made such assessment based on the observation-based modeling approach. Here, diagnosis at Fukue Island (32.75°N, 128.68°E) remotely located in western Japan (May 2009) is highlighted, where the highest 10% of hourly ozone concentrations reached 72‒118 ppb during May influenced by Asian continental outflow. The average in-situ ozone production rate was estimated to be 6.8 ppb per day, suggesting that in-travel production was still active, while larger buildup must have occurred beforehand. Information on the chemical status of the air mass arriving in Japan is important, because it affects how further ozone production occurs after precursor addition from Japanese domestic emissions. The main limiting factor of ozone production was usually NOx, suggesting that domestic NOx emission control is important in reducing further ozone production and the incidence of warning issuance (>120 ppb). VOCs also increased the ozone production rate, and occasionally (14% of time) became dominant. This analysis implies that the VOC reduction legislation recently enacted should be effective. The uncertainty in the radical chemistry mechanism governing ozone production had a non-negligible impact, but the main conclusion relevant to policy was not altered. When chain termination was augmented by HO2-H2O + NO/NO2 reactions and by heterogeneous loss of HO2 on aerosol particle surfaces, the daily ozone production rate decreased by <24%, and the fraction of hours when the VOC-limited condition occurred varied from 14% to 13

  15. Ozone depletion during solar proton events in solar cycle 21

    NASA Technical Reports Server (NTRS)

    Mcpeters, R. D.; Jackman, C. H.

    1985-01-01

    Ozone profile data from the Solar Backscattered Ultraviolet Instrument on Nimbus 7 from 1979 to the present and clear cases of ozone destruction associated with five sudden proton events (SPEs) on June 7, 1979, August 21, 1979, October 13-14, 1981, July 13, 1982, and December 8, 1982 are found. During the SPE on July 13, 1982, the largest of this solar cycle, no depletion at all at 45 km is observed, but there is a 15 percent ozone depletion at 50 km increasing to 27 percent at 55 km, all at a solar zenith angle of 85 deg. A strong variation of the observed depletion with solar zenith angle is found, with maximum depletion occurring at the largest zenith angles (near 85 deg) decreasing to near zero for angles below about 70 deg. The observed depletion is short lived, disappearing within hours of the end of the SPE.

  16. Effects of ozone and peroxyacetyl nitrate on polar lipids and fatty acids in leaves of morning glory and kidney bean. [Pharbitis nil; Phaseolus vulgaris

    SciTech Connect

    Nouchi, Isamu; Toyama, Susumu Ochanomizu Univ., Tokyo )

    1988-07-01

    To compare the effects of ozone and peroxyacetyl nitrate (PAN) on leaf lipids, fatty acids and malondialdehyde (MDA), morning glory (Pharbitis nil Choisy cv Scarlet O'Hara) and kidney bean (Phaseolus vulgaris L. cv Gintebo) plants were exposed to either ozone (0.15 microliter per liter for 8 hours) or PAN (0.10 microliter per liter for up to 8 hours). Ozone increased phospholipids in morning glory and decreased in kidney bean at the initial stage (2-4 hours) of exposure, while it scarcely changed glycolipids, the unsaturated fatty acids, and MDA in both plants. A large reduction of glycolipids occurred 1 day after ozone exposure in both plants. PAN caused marked drops in phospholipids and glycolipids in kidney bean at relatively late stage (6-8 hours) of exposure, while it increased phosphatidic acid and decreased the unsaturated fatty acids, an increase which was accompanied by a large increase in MDA. These results suggest that ozone may not directly oxidize unsaturated fatty acids at the initial stage of exposure, but may alter polar lipid metabolism, particularly phospholipids. On the other hand, PAN may abruptly and considerably degrade phospholipids and glycolipids by peroxidation or hydrolysis at the late stage of exposure. The present study shows that ozone and PAN affect polar lipids in different manners.

  17. Ozone-induced changes in the expression of the genes encoding regulatory enzymes for polyamine, ethylene and phenylpropanoid metabolisms in ozone tolerant and sensitive birch (Betula pendula Roth) clones

    SciTech Connect

    Talvinen, J.; Pellinen, R.; Eloranta, T.; Kangasjaervi, J. ); Julkunen-Tiitto, R. ); Karjalainen, R. )

    1993-05-01

    Increase in the atmospheric ozone concentration has been shown to affect plant growth in several ways; from decreased photosynthetic activity to visible dames and in some extreme situations even to tissue death. Plants protect themselves from the damaging effect of ozone by inducing several physiological reactions. For example, increases in ethylene production, polyamine and phenylpropanoid synthesis have been observed in stress reaction induced by increased atmospheric ozone. similar changes, which are often called general stress reactions, are induced by several other biotic and which are often called general stress reactions, are induced by several other biontic and abiotic factors, e.g., plant pathogens. It has been shown previously that the production of stress ethylene can partly be responsible for the ozone damage formation in plants. Induction of stress-polyamine synthesis can prevent ethylene formation and is higher in some ozone-tolerant plants. We have exposed ozone sensitive and resistant birch clones to ozone (150 ppb. 8 hours) to analyze ozone-induced changes in the phenylpropanoid and polyamine metabolisms and gene expression. The polyamine and phenylpropanoid contents of the experimental material are currently being analyzed and the results will be presented. We have also cloned by PCR gene probes for birch ACC-synthase, arginine decarboxylase (ADC) and phenylalanine ammoniumlyase (PAL) genes. Results will be presented where the probes have been used to analyze ozone-induced expression of the genes in the birch clones.

  18. The influence of meteorological factors and biomass burning on surface ozone concentrations at Tanah Rata, Malaysia

    NASA Astrophysics Data System (ADS)

    Toh, Ying Ying; Lim, Sze Fook; von Glasow, Roland

    2013-05-01

    The surface ozone concentrations at the Tanah Rata regional Global Atmosphere Watch (GAW) station, Malaysia (4°28‧N, 101°23‧E, 1545 m above Mean Sea Level (MSL)) from June 2006 to August 2008 were analyzed in this study. Overall the ozone mixing ratios are very low; the seasonal variations show the highest mixing ratios during the Southwest monsoon (average 19.1 ppb) and lowest mixing ratios during the spring intermonsoon (average 14.2 ppb). The diurnal variation of ozone is characterised by an afternoon maximum and night time minimum. The meteorological conditions that favour the formation of high ozone levels at this site are low relative humidity, high temperature and minimum rainfall. The average ozone concentration is lower during precipitation days compared to non-precipitation days. The hourly averaged ozone concentrations show significant correlations with temperature and relative humidity during the Northeast monsoon and spring intermonsoon. The highest concentrations are observed when the wind is blowing from the west. We found an anticorrelation between the atmospheric pressure tide and ozone concentrations. The ozone mixing ratios do not exceed the recommended Malaysia Air Quality Guidelines for 1-h and 8-h averages. Five day backward trajectories on two high ozone episodes in 07 August 2006 (40.0 ppb) and 24 February 2008 (45.7 ppb) are computed using the HYbrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model to investigate the origin of the pollutants and influence of regional transport. The high ozone episode during 07 August 2006 (burning season during southwest monsoon) is mainly attributed to regional transport from biomass burning in Sumatra, whereas favourable meteorological conditions (i.e. low relative humidity, high temperature and solar radiation, zero rainfall) and long range transport from Indo-China have elevated the ozone concentrations during 24 February 2008.

  19. The potential near-source ozone impacts of upstream oil and gas industry emissions.

    PubMed

    Olaguer, Eduardo P

    2012-08-01

    Increased drilling in urban areas overlying shale formations and its potential impact on human health through decreased air quality make it important to estimate the contribution of oil and gas activities to photochemical smog. Flares and compressor engines used in natural gas operations, for example, are large sources not only of NOx but also offormaldehyde, a hazardous air pollutant and powerful ozone precursor We used a neighborhood scale (200 m horizontal resolution) three-dimensional (3D) air dispersion model with an appropriate chemical mechanism to simulate ozone formation in the vicinity ofa hypothetical natural gas processing facility, based on accepted estimates of both regular and nonroutine emissions. The model predicts that, under average midday conditions in June, regular emissions mostly associated with compressor engines may increase ambient ozone in the Barnett Shale by more than 3 ppb beginning at about 2 km downwind of the facility, assuming there are no other major sources of ozone precursors. Flare volumes of 100,000 cubic meters per hour ofnatural gas over a period of 2 hr can also add over 3 ppb to peak 1-hr ozone somewhatfurther (>8 km) downwind, once dilution overcomes ozone titration and inhibition by large flare emissions of NOx. The additional peak ozone from the hypothetical flare can briefly exceed 10 ppb about 16 km downwind. The enhancements of ambient ozone predicted by the model are significant, given that ozone control strategy widths are of the order of a few parts per billion. Degrading the horizontal resolution of the model to 1 km spuriously enhances the simulated ozone increases by reducing the effectiveness of ozone inhibition and titration due to artificial plume dilution. PMID:22916444

  20. Role of neutrophilic inflammation in ozone-induced epithelial alterations in the nasal airways of rats

    NASA Astrophysics Data System (ADS)

    Cho, Hye Youn

    Ozone is a principal oxidant air pollutant in photochemical smog. Epithelial cells lining the centriacinar region of lung and the proximal aspects of nasal passage are primary target sites for ozone-induced injury in laboratory animals. Acute exposure of rats to high ambient concentrations of ozone (e.g., 0.5 ppm) results in neutrophilic inflammation, epithelial hyperplasia and mucous cell metaplasia (MCM) in the nasal transitional epithelium (NTE) lining the proximal nasal airways. The principal purpose of the present study was to investigate the role of pre-metaplastic cellular responses, especially neutrophilic inflammation, in the pathogenesis of ozone-induced MCM in rat NTE. For this purpose, three specific hypotheses-based whole-animal inhalation studies were conducted. Male F344/N rats were exposed in whole-body inhalation chambers to 0 (filtered air) or 0.5 ppm ozone for 1-3 days (8 h/day). Histochemical, immunochemical, molecular and morphometric techniques were used to investigate the ozone-induced cellular and molecular events in the NTE. Two in vitro studies were also conducted to examine the effects of ozone-inducible cytokines (i.e., tumor necrosis factor-alpha; TNF- a, and interleukin-6; IL-6) on mucin gene (rMuc-5AC) expression. Ozone induced a rapid increase of rMuc-5AC mRNA in nasal tissues within hours after the start of exposure. It preceded the appearance of MCM, and persisted with MCM. Ozone-induced neutrophilic inflammation accompanied the mucin gene upregulation, but was resolved when MCM first appeared in the NTE. Antibody-mediated depletion of circulating neutrophils attenuated ozone-induced MCM, although it did not affect the ozone-induced epithelial hyperplasia and mucin mRNA upregulation. In another study, it was found that preexisting neutrophilic rhinitis induced by endotoxin augmented the ozone-induced MCM. However, pre-existing rhinitis did not alter the severity of ozone-induced epithelial hyperplasia and mucin gene upregulation

  1. The 1987 Airborne Antarctic Ozone Experiment: the Nimbus-7 TOMS Data Atlas

    NASA Technical Reports Server (NTRS)

    Krueger, Arlin J.; Ardanuy, Philip E.; Sechrist, Frank S.; Penn, Lanning M.; Larko, David E.; Doiron, Scott D.; Galimore, Reginald N.

    1988-01-01

    Total ozone data taken by the Nimbus-7 Total Ozone Mapping Spectrometer (TOMS) played a central role in the successful outcome of the 1987 Airborne Antarctic Ozone Experiment. The near-real-time TOMS total ozone observations were suppled within hours of real time to the operations center in Punta Arenas, Chile, over a telecommunications network designed specifically for this purpose. The TOMS data preparation and method of transfer over the telecommunications links are reviewed. This atlas includes a complete set of the near-real-time TOMS orbital overpass data over regions around the Palmer Peninsula of Antarctica for the period of August 8 through September 29, 1987. Also provided are daily polar orthographic projections of TOMS total ozone measurements over the Southern Hemisphere from August through November 1987. In addition, a chronology of the salient points of the experiment, along with some latitudinal cross sections and time series at locations of interest of the TOMS total ozone observations are presented. The TOMS total ozone measurements are evaluated along the flight tracks of each of the ER-2 and DC-8 missions during the experiment. The ozone hole is shown here to develop in a monotonic progression throughout late August and September. The minimum total ozone amount was found on 5 October, when its all-time lowest value of 109 DU is recorded. The hole remains well defined, but fills gradually from mid-October through mid-November. The hole's dissolution is observed here to begin in mid-November, when it elongates and begins to rotate. By the end of November, the south pole is no longer located within the ozone hole.

  2. [Treatment of petrochemical secondary effluent by ozone-biological aerated filter].

    PubMed

    Liu, Ming-Guo; Wu, Chang-Yong; Zhou, Yue-Xi; Gao, Zhen; Wang, Pei-Chao; Yang, Qi; Dong, De

    2014-02-01

    The advanced treatment of petrochemical secondary wastewater by ozone- aerated biological filter was carried out in this study. The effect of pH on ozonation and the removal of COD and UV254 by the ozone-aerated biological filter combined process were investigated. In addition, the variation of relative molecular mass distribution of organics and the characteristics of three-dimensional fluorescence spectra of the wastewater were also investigated. The results showed that the suitable operating conditions of the ozonation unit were: ozone dosage 10 mg x L(-1), contact time 4 min and slightly alkaline pH. Ozonation can transfer macromolecular organics into small molecular organics, resulting in a 15% increase in the percentage of the organics with small relative molecular mass (less than 1 000). The biodegradability of the petrochemical secondary effluent was significantly improved by ozonation, making it more suitable for the treatment by aerated biological filter. The removal efficiency of COD and UV254 were 40.8% and 45.8% when the hydraulic retention time was 3 hours and the gas to water ratio was 3:1 for BAF. The average COD of the petrochemical wastewater was 86.5 mg x L(-1) while the average COD of the effluent of the combined process was 49.4 mg x L(-1) when it was operated under optimal conditions.

  3. Improving the Current Understanding of the Evolution and Vertical Processes of Tropospheric Ozone Using a Ground Based Differential Absorption Lidar

    NASA Astrophysics Data System (ADS)

    Sullivan, John T.

    Although characterizing the interactions of ozone throughout the entire troposphere are important for health and climate processes, there is a lack of routine measurements of vertical profiles within the United States. Current atmospheric satellite instruments cannot peer through the optically thick stratospheric ozone layer to remotely sense boundary layer tropospheric ozone. In order to monitor this lower ozone more effectively, the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center TROPospheric OZone DIfferential Absorption Lidar (GSFC TROPOZ DIAL) has been developed and validated within the Tropospheric Ozone Lidar Network (TOLNet). Two scientifically interesting ozone episodes are presented that were observed during the 2014 Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality (DISCOVER AQ) campaign at Ft. Collins, Colorado. The GSFC TROPOZ DIAL measurements are analyzed alongside aircraft spirals over the lidar site, co-located ozonesonde launches, aerosol lidar profiles and other TOLNet ozone lidar profiles. In both case studies, back trajectories, meteorological maps, and comparisons to air quality models are presented to better explain the sources and evolution of ozone. The first case study, occurring between 22-23 July 2014, indicates enhanced concentrations of ozone at Ft. Collins during nighttime hours, which was due to the complex recirculation of ozone within the foothills of the Rocky Mountain region. Although quantifying the ozone increase aloft during recirculation episodes has been historically difficult, results indicate that an increase of 20 - 30 ppbv of ozone at the Ft. Collins site has been attributed to this recirculation. The second case, occurring between Aug 4-8th 2014, characterizes a dynamical exchange of ozone between the stratosphere and the troposphere. This case, along with seasonal model parameters from previous years, is used to estimate

  4. Effect of exposures to ambient ozone on ventilatory lung function in children

    SciTech Connect

    Higgins, I.T.; D'Arcy, J.B.; Gibbons, D.I.; Avol, E.L.; Gross, K.B. )

    1990-05-01

    This study was undertaken to determine if the ventilatory capacity of children is affected by hourly concentrations of ozone inhaled during their daily activity. Over a 3-wk period children who were attending a summer camp in the San Bernardino mountains of California performed spirometry up to three times per day during their stay at the camp. Ozone, oxides of nitrogen, sulfur dioxide, temperature, and relative humidity were measured continuously. Daily average measurements of total suspended particulate and the PM10 particulate fraction were also made. Hourly ozone concentrations at the time of testing varied between 20 and 245 ppb. Regressions of each individual's FEV1 and FVC supported the view that high ozone levels reduced these lung function parameters. The average regression coefficient for FEV1 on ozone was -0.39 ml/ppb (SEM = 0.12) and for FVC -0.44 ml/ppb (SEM = 0.15), both of which were significantly different from zero. Statistical allowance for temperature and humidity increased the magnitude of these slopes. Nitrogen dioxide never exceeded 40 ppb during the time of testing and averaged 13 ppb. Sulfur dioxide's highest measurement was 8 ppb and often was at the limit of detection. Neither NO2 nor SO2 was considered in the statistical modeling. Data were divided based on whether each subject had been exposed to levels of ozone in excess of the National Ambient Air Quality Standard (NAAQS) during the several hours previous to being tested. Exposures exceeding the NAAQS indicated a significant negative relationship between ozone and FEV1, FVC, and PEFR. Data for nonexceedance periods did not indicate this negative relationship for any of the three lung function parameters, but it could not be determined if this was due to an absence of an ozone effect or to a combination of the increased variability and decreased size of this data subset.

  5. Tropospheric ozone in the vicinity of the ozone hole: 1987 Airborne Antarctic Ozone Experiment

    SciTech Connect

    Gregory, G.L.; Warren, L.S. ); Hypes, W.D. ); Tuck, A.F.; Kelly, K.K. ); Krueger, A.J. )

    1989-11-30

    Tropospheric ozone measurements over Antarctica aboard the NASA DC-8 aircraft are summarized. As part of the August/September 1987 Airborne Antarctic Ozone Experiment, the aircraft flew 13 missions covering a latitude of 53{degree}-90{degree}S, at altitudes to 13 km. Ozone mixing ratios as high as several hundred parts per billion by volume (ppbv) were measured, but in all cases these ratios were observed in pockets or patches of upper atmospheric air. These pockets were observed both in the vicinity of and away from the location of the ozone hole. At times, and as a result of these pockets, the ozone levels at the flight altitude of the aircraft, as averaged beneath the boundaries of the stratospheric ozone hole, were 2-3 times higher than background tropospheric values. The data suggest that the ozone-rich air seldom penetrated below about 9-km altitude. Background ozone values in the surrounding troposphere were typically in the range of 20-50 ppbv. Correlation of tropospheric ozone observations with the boundaries of the ozone hole differed during the experiment. During the early flights (August 28 through September 2), encounters with ozone-rich air were limited and background tropospheric ozone (at the flight altitude) appeared to decrease beneath the hole. For many of the later flights, and as the hole deepened, the reverse was noted, in that ozone-rich air was frequently observed in the vicinity of the hole and, as noted earlier, average ozone at the flight altitude was frequently higher than background values.

  6. The Impact of Emission and Climate Change on Ozone in the United States under Representative Concentration Pathways (RCPs)

    SciTech Connect

    Gao, Yang; Fu, Joshua S.; Drake, John B.; Lamarque, J.-F.; Liu, Yang

    2013-09-27

    Dynamical downscaling was applied in this study to link the global climate-chemistry model Community Atmosphere Model (CAM-Chem) with the regional models: Weather Research and Forecasting (WRF) Model and Community Multi-scale Air Quality (CMAQ). Two Representative Concentration Pathway (RCP) scenarios (RCP 4.5 and RCP 8.5) were used to evaluate the climate impact on ozone concentrations in 2050s. Ozone concentrations in the lower-mid troposphere (surface to ~300 hPa), from mid- to high latitudes in the Northern Hemisphere (NH), show decreasing trends in RCP 4.5 between 2000s and 2050s, with the largest decrease of 4-10 ppbv occurring in the summer and the fall; and increasing trends (2-12 ppbv) in RCP 8.5 resulting from the increased methane emissions. In RCP 8.5, methane emissions increase by ~60% by the end of 2050s, accounting for more than 90% of ozone increases in summer and fall, and 60-80% in spring and winter. Under the RCP 4.5 scenario, in the summer when photochemical reactions are the most active, the large ozone precursor emissions reduction leads to the greatest decrease of downscaled surface ozone concentrations, ranging from 6 to 10 ppbv. However, a few major cities show ozone increases of 3 to 7 ppbv due to weakened NO titration. Under the RCP 8.5 scenario, in winter, downscaled ozone concentrations increase across nearly the entire continental US in winter, ranging from 3 to 10 ppbv due to increased methane emissions and enhanced stratosphere-troposphere exchange (STE). More intense heat waves are projected to occur by the end of 2050s in RCP 8.5, leading to more than 8 ppbv of the maximum daily 8-hour daily average (MDA8) ozone during the heat wave days than other days; this indicates the dramatic impact heat waves exert on high frequency ozone events.

  7. The 1991 Antarctic ozone hole - TOMS observations

    NASA Technical Reports Server (NTRS)

    Krueger, Arlin; Schoeberl, Mark; Newman, Paul; Stolarski, Richard

    1992-01-01

    The 1991 Antarctic springtime ozone decline, as measured by the Total Ozone Mapping Spectrometer (TOMS), was similar to those of earlier deep ozone hole years, 1987, 1989, and 1990. The minimum total ozone value was recorded on October 5, 1991 at 108 Dobson units near the South Pole. This was 8 DU lower than in any of the earlier years. Four of the last five years have exhibited an extensive, deep ozone hole. The area of the hole was about the same as in 1987, 1989, and 1990. The recovery of the low total ozone values occurred in mid-November as the polar vortex broke up.

  8. Comparative Effects of Gamma Irradiation and Ozone Treatment on Hygienic Quality of Korean Red Ginseng Powder

    NASA Astrophysics Data System (ADS)

    Byun, Myung-Woo; Yook, Hong-Sun; Kang, Il-Jun; Chung, Cha-Kwon; Kwon, Joong-Ho; Choi, Kang-Ju

    1998-06-01

    For the purpose of improving hygienic quality of Korean red ginseng powder, the comparative effects of gamma irradiation and ozone treatment on the microbial and physicochemical properties were investigated. Gamma irradiation at 7.5 kGy resulted in sterilization of total aerobic bacteria, molds and coliforms below detective levels, while ozone treatment for 8 hours up to 18 ppm did not sufficiently eliminate the microorganisms of the red ginseng powder. Physicochemical properties including compositions of the red ginseng saponin (ginsenosides) and fatty acids, pH and hydrogen doanting activity were not significantly changed by gamma irradiation, whereas, ozone treatment caused significant changes in fatty acid compositions, TBA value, pH, acidity and hydrogen donating activity. The results from this study led us to conclude that gamma irradiation was more effective than ozone treatment both for the improvement of hygienic quality and for the maintenance of physicochemical quality of red ginseng powder.

  9. Ozone Air Quality Impacts of Shale Gas Development in South Texas Urban Areas

    NASA Astrophysics Data System (ADS)

    Chang, C.; Liao, K.

    2013-12-01

    Recent technological advances, mainly horizontal drilling and hydraulic fracturing, and continued drilling in shale, have increased domestic production of oil and gas in the United State (U.S.). However, shale gas developments could also affect the environment and human health, particularly in areas where oil and gas developments are new activities. This study is focused on the impacts of shale gas developing activities on summertime ozone air quality in South Texas urban areas since many of them are already ozone nonattainment areas. We use an integrated approach to investigate the ozone air quality impact of the shale gas development in South Texas urban areas. They are: (1) satellite measurement of precursors, (2) observations of ground-level ozone concentrations, and (3) air mass trajectory modeling. Nitrogen dioxide (NO2) is an important precursor to ozone formation, and summertime average tropospheric nitrogen dioxide (NO2) column densities measured by the National Aeronautics and Space Administration's Ozone Monitoring Instrument increased in the South Texas shale area (i.e., the Eagle Ford Shale area) in 2011 and 2012 as compared to 2008-2010. The U.S. Environmental Protection Agency's ground-level observations showed summertime average and peak ozone (i.e., the 4th highest daily maximum 8-hour average ozone) concentrations slightly increased from 2010 to 2012 in Austin and San Antonio. However, the frequencies of peak ozone concentrations above the 75ppb ozone standard have been significantly increasing since 2011 in Austin and San Antonio. It is expected to increase the possibilities of violating the ozone National Ambient Air Quality Standard (NAAQS) for South Texas urban areas in the future. The results of trajectory modeling showed air masses transported from the southeastern Texas could reach Austin and San Antonio and confirmed that emissions from the Eagle Ford Shale area could affect ozone air quality in South Texas urban areas in 2011 and 2012

  10. Acute pulmonary toxicity of urban particulate matter and ozone.

    PubMed Central

    Vincent, R.; Bjarnason, S. G.; Adamson, I. Y.; Hedgecock, C.; Kumarathasan, P.; Guénette, J.; Potvin, M.; Goegan, P.; Bouthillier, L.

    1997-01-01

    We have investigated the acute lung toxicity of urban particulate matter in interaction with ozone. Rats were exposed for 4 hours to clean air, ozone (0.8 ppm), the urban dust EHC-93 (5 mg/m3 or 50 mg/m3), or ozone in combination with urban dust. The animals were returned to clean air for 32 hours and then injected (intraperitoneally) with [3H]thymidine to label proliferating cells and killed after 90 minutes. The lungs were fixed by inflation, embedded in glycol methacrylate, and processed for light microscopy autoradiography. Cell labeling was low in bronchioles (0.14 +/- 0.04%) and parenchyma (0.13 +/- 0.02%) of air control animals. Inhalation of EHC-93 alone did not induce cell labeling. Ozone alone increased (P < 0.05) cell labeling (bronchioles, 0.42 +/- 0.16%; parenchyma, 0.57 +/- 0.21%), in line with an acute reparative cell proliferation. The effects of ozone were clearly potentiated by co-exposure with either the low (3.31 +/- 0.31%; 0.99 +/- 0.18%) or the high (4.45 +/- 0.51%; 1.47 +/- 0.18%) concentrations of urban dust (ozone X EHC-93, P < 0.05). Cellular changes were most notable in the epithelia of terminal bronchioles and alveolar ducts and did not distribute to the distal parenchyma. Enhanced DNA synthesis indicates that particulate matter from ambient air can exacerbate epithelial lesions in the lungs. This may extend beyond air pollutant interactions, such as to effects of inhaled particles in the lungs of compromised individuals. Images Figure 1 PMID:9403707

  11. Activation of transcription factor IL-6 (NF-IL-6) and nuclear factor-kappaB (NF-kappaB) by lipid ozonation products is crucial to interleukin-8 gene expression in human airway epithelial cells.

    PubMed

    Kafoury, Ramzi M; Hernandez, Jazmir M; Lasky, Joseph A; Toscano, William A; Friedman, Mitchell

    2007-04-01

    Ozone (O(3)) is a major component of smog and an inhaled toxicant to the lung. O(3) rapidly reacts with the airway epithelial cell membrane phospholipids to generate lipid ozonation products (LOP). 1-Hydroxy-1-hydroperoxynonane (HHP-C9) is an important LOP, produced from the ozonation of 1-palmitoyl-2-oleoyl-sn-glycerol-3-phosphatidylcholine. This LOP, at a biologically relevant concentration (100 microM), increases the activity of phospholipase C, nuclear factors-kappaB (NF-kappaB), and interleukin-6 (NF-IL-6) and the expression of the inflammatory gene, interleukin-8 (IL-8) in a cultured human bronchial epithelial cell line (BEAS-2B). The signaling pathways of ozone and its biologically-active products are as yet undefined. In the present study, we report that the HHP LOP, HHP-C9 (100 microM x 4 h), activated the expression of IL-8 (218 +/- 26% increase over control, n = 4, P < 0.01) through an apparent interaction between the two transcription factors, NF-kappaB and NF-IL-6. Transfection studies using luciferase reporter assays demonstrated that HHP-C9 induced a significant increase in NF-kappaB-DNA binding activity (37 +/- 7% increase over control, n = 6, P < 0.05). Inhibition of NF-kappaB showed a statistically significant but modest decrease in IL-8 release, which suggested a role for another transcription factor, NF-IL-6. Exposure of BEAS-2B cells to HHP-C9 induced a significant increase in the DNA binding activity of NF-IL-6 (45 +/- 11% increase over control, n = 6, P < 0.05). The results of the present study indicate that NF-IL-6 interacts with NF-kappaB in regulating the expression of IL-8 in cultured human airway epithelial cells exposed to LOP, the biological products of ozone in the lung. PMID:17366569

  12. Projections of Future Summertime Ozone over the U.S.

    SciTech Connect

    Pfister, G. G.; Walters, Stacy; Lamarque, J. F.; Fast, Jerome D.; Barth, Mary; Wong, John; Done, James; Holland, Greg; Bruyere, Cindy

    2014-05-05

    This study uses a regional fully coupled chemistry-transport model to assess changes in surface ozone over the summertime U.S. between present and a 2050 future time period at high spatial resolution (12 km grid spacing) under the SRES A2 climate and RCP8.5 anthropogenic pre-cursor emission scenario. The impact of predicted changes in climate and global background ozone is estimated to increase surface ozone over most of the U.S; the 5th - 95th percentile range for daily 8-hour maximum surface ozone increases from 31-79 ppbV to 30-87 ppbV between the present and future time periods. The analysis of a set of meteorological drivers suggests that these mostly will add to increasing ozone, but the set of simulations conducted does not allow to separate this effect from that through enhanced global background ozone. Statistically the most robust positive feedbacks are through increased temperature, biogenic emissions and solar radiation. Stringent emission controls can counteract these feedbacks and if considered, we estimate large reductions in surface ozone with the 5th-95th percentile reduced to 27-55 ppbV. A comparison of the high-resolution projections to global model projections shows that even though the global model is biased high in surface ozone compared to the regional model and compared to observations, both the global and the regional model predict similar changes in ozone between the present and future time periods. However, on smaller spatial scales, the regional predictions show more pronounced changes between urban and rural regimes that cannot be resolved at the coarse resolution of global model. In addition, the sign of the changes in overall ozone mixing ratios can be different between the global and the regional predictions in certain regions, such as the Western U.S. This study confirms the key role of emission control strategies in future air quality predictions and demonstrates the need for considering degradation of air quality with future

  13. A fully remote control cryogenless ozone precursor system with improved sensitivity

    SciTech Connect

    Cardin, D.B.; Deschenes, J.T.

    1994-12-31

    In compliance with Title 1 of the 1990 Clean Air Act Amendment (1990 CAAA), hydrocarbons in the C2-C10 molecular weight range will be monitored to assess their contribution to ozone formation in approximately 35 cities which exceed current ozone standards during summer months. A cryogenless C2-C10 ``AUTOGC`` system is presented that exceeds the monitoring requirements specified in the technical assistance document for ozone precursor monitoring. Samples can be analyzed hourly or once every 3, 8, or 24 hours to provide as much resolution as necessary. Sampling frequency can be changed via modem to accommodate periods of high and low ozone concentrations. A benchtop 16-position manifold makes it possible to analyze other gas streams at programmed intervals, such as propane and hexane standards, retention time standards, and system blanks. Integration of the ambient air sample first into a canister allows standards and blanks to be run while continuing to analyze ambient air 24 hours per day. Access to the GC/FID and preconcentrator are possible via modem using a Windows{trademark} interface for data retrieval, verification of proper operation, and adjustment of method parameters. Data will be presented showing performance in determining ozone precursor concentrations in Los Angeles, California.

  14. 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...

  15. 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...

  16. 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...

  17. 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...

  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 52.2275 - 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...

  20. 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...

  1. 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...

  2. 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...

  3. 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...

  4. Ozone-Induced Nasal Type 2 Immunity in Mice Is Dependent on Innate Lymphoid Cells.

    PubMed

    Kumagai, Kazuyoshi; Lewandowski, Ryan; Jackson-Humbles, Daven N; Li, Ning; Van Dyken, Steven J; Wagner, James G; Harkema, Jack R

    2016-06-01

    Epidemiological studies suggest that elevated ambient concentrations of ozone are associated with activation of eosinophils in the nasal airways of atopic and nonatopic children. Mice repeatedly exposed to ozone develop eosinophilic rhinitis and type 2 immune responses. In this study, we determined the role of innate lymphoid cells (ILCs) in the pathogenesis of ozone-induced eosinophilic rhinitis by using lymphoid-sufficient C57BL/6 mice, Rag2(-/-) mice that are devoid of T cells and B cells, and Rag2(-/-)Il2rg(-/-) mice that are depleted of all lymphoid cells including ILCs. The animals were exposed to 0 or 0.8 ppm ozone for 9 consecutive weekdays (4 h/d). Mice were killed 24 hours after exposure, and nasal tissues were selected for histopathology and gene expression analysis. ILC-sufficient C57BL/6 and Rag2(-/-) mice exposed to ozone developed marked eosinophilic rhinitis and epithelial remodeling (e.g., epithelial hyperplasia and mucous cell metaplasia). Chitinase-like proteins and alarmins (IL-33, IL-25, and thymic stromal lymphopoietin) were also increased morphometrically in the nasal epithelium of ozone-exposed C57BL/6 and Rag2(-/-) mice. Ozone exposure elicited increased expression of Il4, Il5, Il13, St2, eotaxin, MCP-2, Gob5, Arg1, Fizz1, and Ym2 mRNA in C57BL/6 and Rag2(-/-) mice. In contrast, ozone-exposed ILC-deficient Rag2(-/-)Il2rg(-/-) mice had no nasal lesions or overexpression of Th2- or ILC2-related transcripts. These results indicate that ozone-induced eosinophilic rhinitis, nasal epithelial remodeling, and type 2 immune activation are dependent on ILCs. To the best of our knowledge, this is the first study to demonstrate that ILCs play an important role in the nasal pathology induced by repeated ozone exposure.

  5. Unraveling the sources of ground level ozone in the Intermountain Western United States using Pb isotopes.

    PubMed

    Christensen, John N; Weiss-Penzias, Peter; Fine, Rebekka; McDade, Charles E; Trzepla, Krystyna; Brown, Shaun T; Gustin, Mae Sexauer

    2015-10-15

    Ozone as an atmospheric pollutant is largely produced by anthropogenic precursors and can significantly impact human and ecosystem health, and climate. The U.S. Environmental Protection Agency has recently proposed lowering the ozone standard from 75 ppbv (MDA8 = Maximum Daily 8-Hour Average) to between 65 and 70 ppbv. This will result in remote areas of the Intermountain West that includes many U.S. National Parks being out of compliance, despite a lack of significant local sources. We used Pb isotope fingerprinting and back-trajectory analysis to distinguish sources of imported ozone to Great Basin National Park in eastern Nevada. During discrete Chinese Pb events (> 1.1 ng/m(3) & > 80% Asian Pb) trans-Pacific transported ozone was 5 ± 5.5 ppbv above 19 year averages for those dates. In contrast, concentrations during regional transport from the Los Angeles and Las Vegas areas were 15 ± 2 ppbv above the long-term averages, and those characterized by high-altitude transport 3 days prior to sampling were 19 ± 4ppbv above. However, over the study period the contribution of trans-Pacific transported ozone increased at a rate of 0.8 ± 0.3 ppbv/year, suggesting that Asian inputs will exceed regional and high altitude sources by 2015-2020. All of these sources will impact regulatory compliance with a new ozone standard, given increasing global background.

  6. Unraveling the sources of ground level ozone in the Intermountain Western United States using Pb isotopes.

    PubMed

    Christensen, John N; Weiss-Penzias, Peter; Fine, Rebekka; McDade, Charles E; Trzepla, Krystyna; Brown, Shaun T; Gustin, Mae Sexauer

    2015-10-15

    Ozone as an atmospheric pollutant is largely produced by anthropogenic precursors and can significantly impact human and ecosystem health, and climate. The U.S. Environmental Protection Agency has recently proposed lowering the ozone standard from 75 ppbv (MDA8 = Maximum Daily 8-Hour Average) to between 65 and 70 ppbv. This will result in remote areas of the Intermountain West that includes many U.S. National Parks being out of compliance, despite a lack of significant local sources. We used Pb isotope fingerprinting and back-trajectory analysis to distinguish sources of imported ozone to Great Basin National Park in eastern Nevada. During discrete Chinese Pb events (> 1.1 ng/m(3) & > 80% Asian Pb) trans-Pacific transported ozone was 5 ± 5.5 ppbv above 19 year averages for those dates. In contrast, concentrations during regional transport from the Los Angeles and Las Vegas areas were 15 ± 2 ppbv above the long-term averages, and those characterized by high-altitude transport 3 days prior to sampling were 19 ± 4ppbv above. However, over the study period the contribution of trans-Pacific transported ozone increased at a rate of 0.8 ± 0.3 ppbv/year, suggesting that Asian inputs will exceed regional and high altitude sources by 2015-2020. All of these sources will impact regulatory compliance with a new ozone standard, given increasing global background. PMID:25934382

  7. Impact of climate change on ambient ozone level and mortality in southeastern United States.

    PubMed

    Chang, Howard H; Zhou, Jingwen; Fuentes, Montserrat

    2010-07-01

    There is a growing interest in quantifying the health impacts of climate change. This paper examines the risks of future ozone levels on non-accidental mortality across 19 urban communities in Southeastern United States. We present a modeling framework that integrates data from climate model outputs, historical meteorology and ozone observations, and a health surveillance database. We first modeled present-day relationships between observed maximum daily 8-hour average ozone concentrations and meteorology measured during the year 2000. Future ozone concentrations for the period 2041 to 2050 were then projected using calibrated climate model output data from the North American Regional Climate Change Assessment Program. Daily community-level mortality counts for the period 1987 to 2000 were obtained from the National Mortality, Morbidity and Air Pollution Study. Controlling for temperature, dew-point temperature, and seasonality, relative risks associated with short-term exposure to ambient ozone during the summer months were estimated using a multi-site time series design. We estimated an increase of 0.43 ppb (95% PI: 0.14-0.75) in average ozone concentration during the 2040's compared to 2000 due to climate change alone. This corresponds to a 0.01% increase in mortality rate and 45.2 (95% PI: 3.26-87.1) premature deaths in the study communities attributable to the increase in future ozone level.

  8. The sensitivity of modeled ozone to the temporal distribution of point, area, and mobile source emissions in the eastern United States

    NASA Astrophysics Data System (ADS)

    Castellanos, Patricia; Stehr, Jeffrey W.; Dickerson, Russell R.; Ehrman, Sheryl H.

    Ozone remains one of the most recalcitrant air pollution problems in the US. Hourly emissions fields used in air quality models (AQMs) generally show less temporal variability than corresponding measurements from continuous emissions monitors (CEM) and field campaigns would imply. If emissions control scenarios to reduce emissions at peak ozone forming hours are to be assessed with AQMs, the effect of emissions' daily variability on modeled ozone must be understood. We analyzed the effects of altering all anthropogenic emissions' temporal distributions by source group on 2002 summer-long simulations of ozone using the Community Multiscale Air Quality Model (CMAQ) v4.5 and the Carbon Bond IV (CBIV) chemical mechanism with 12 km resolution. We find that when mobile source emissions were made constant over the course of a day, 8-h maximum ozone predictions changed by ±7 parts per billion by volume (ppbv) in many urban areas on days when ozone concentrations greater than 80 ppbv were simulated in the base case. Increasing the temporal variation of point sources resulted in ozone changes of +6 and -6 ppbv, but only for small areas near sources. Changing the daily cycle of mobile source emissions produces substantial changes in simulated ozone, especially in urban areas at night; results suggest that shifting the emissions of NO x from day to night, for example in electric powered vehicles recharged at night, could have beneficial impacts on air quality.

  9. 78 FR 35764 - Approval and Promulgation of Implementation Plans; New Jersey; Infrastructure SIP for the 1997 8...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-14

    ... and revised NAAQS for 8-hour ozone (62 FR 38856) and PM 2.5 (62 FR 38652). EPA strengthened the 24-hour PM 2.5 NAAQS on October 17, 2006 (71 FR 61144). The 14 elements required to be addressed in... FR 55666). Additionally, this action does not address the requirements of section...

  10. AASE-2 In-Situ Tracer Correlations of Methane Nitrous Oxide and Ozone as Observed Aboard the DC-8

    NASA Technical Reports Server (NTRS)

    Collins, J. E., Jr.; Sachse, G. W.; Anderson, B. E.; Weinheimer, A. J.; Walgea, J. G.; Ridley, B. A.

    1993-01-01

    We report in situ stratospheric measurements of CH4, N2O, and O3 obtained aboard the NASA DC-8 during the January-March 1992 Airborne Arctic Stratospheric Expedition II field campaign. These data demonstrate a strong linear correlation between N2O and CH4 in the lower stratosphere thus indicating that both species are effective tracers of stratospheric air motion. Measurements of both species on constant geometric height surfaces indicate that significant subsidence of the arctic stratospheric air mass occurred at DC-8 altitudes over the course of the AASE-II expedition. In addition, a widespread reduction in O3 mixing ratios (up to 20%) relative to these conserved tracers was also observed in the lower stratosphere in March a compared to January and February results.

  11. AASE-2 in-situ tracer correlations of methane, nitrous oxide, and ozone as observed aboard the DC-8

    NASA Technical Reports Server (NTRS)

    Collins, J. E., Jr.; Sachse, G. W.; Anderson, B. E.; Weinheimer, A. J.; Walega, J. G.; Ridley, B. A.

    1993-01-01

    We report in situ stratospheric measurements of CH4, N2O, and O3 obtained aboard the NASA DC-8 during the January-March 1992 Airborne Arctic Stratospheric Expedition 2 field campaign. These data demonstrate a strong linear correlation between N2O and CH4 in the lower stratosphere thus indicating that both species are effective tracers of stratospheric air motion. Measurements of both species on constant geometric height surfaces indicate that significant subsidence of the arctic stratospheric air mass occurred at DC-8 altitudes over the course of the AASE-2 expedition. In addition, a widespread reduction in O3 mixing ratios (up to 20%) relative to these conserved tracers was also observed in the lower stratosphere in March as compared to January and February results.

  12. 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...

  13. 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

  14. 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. PMID:26109880

  15. 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.

  16. 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.

  17. 78 FR 27161 - Approval and Promulgation of Air Quality Implementation Plans; Connecticut; Ozone Attainment...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-05-09

    ... moderate ozone nonattainment area. See 40 CFR 81.307. Also, on April 30, 2004 (69 FR 23951), EPA...-hour ozone standard will continue with implementation of the 2008 ozone NAAQS. \\2\\ See 73 FR 16436... 2009 ozone season. C. Why is EPA proposing these actions? On August 31, 2010 (75 FR 53219), EPA made...

  18. Reduction of date microbial load with ozone

    PubMed Central

    Farajzadeh, Davood; Qorbanpoor, Ali; Rafati, Hasan; Isfeedvajani, Mohsen Saberi

    2013-01-01

    Background: Date is one of the foodstuffs that are produced in tropical areas and used worldwide. Conventionally, methyl bromide and phosphine are used for date disinfection. The toxic side effects of these usual disinfectants have led food scientists to consider safer agents such as ozone for disinfection, because food safety is a top priority. The present study was performed to investigate the possibility of replacing common conventional disinfectants with ozone for date disinfection and microbial load reduction. Materials and Methods: In this experimental study, date samples were ozonized for 3 and 5 hours with 5 and 10 g/h concentrations and packed. Ozonized samples were divided into two groups and kept in an incubator which was maintained at 25°C and 40°C for 9 months. During this period, every 3 month, microbial load (bacteria, mold, and yeast) were examined in ozonized and non-ozonized samples. Results: This study showed that ozonization with 5 g/h for 3 hours, 5 g/h for 5 hours, 10 g/h for 3 hours, and 10 g/h for 5 hours leads to about 25%, 25%, 53%, and 46% reduction in date mold and yeast load and about 6%, 9%, 76%, and 74.7% reduction in date bacterial load at baseline phase, respectively. Appropriate concentration and duration of ozonization for microbial load reduction were 10 g/h and 3 hours. Conclusion: Date ozonization is an appropriate method for microbial load reduction and leads to an increase in the shelf life of dates. PMID:24124432

  19. 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

  20. Measurements of Nitric Acid and Aerosol Species Aboard the NASA DC-8 Aircraft During the SASS OZone and Nitrogen Oxide Experiment (SONEX)

    NASA Technical Reports Server (NTRS)

    Talbot, Robert W.; Dibb, Jack E.

    1999-01-01

    The SASS Ozone and Nitrogen Oxides Experiment (SONEX) over the north Atlantic during October/November 1997 offered an excellent opportunity to examine the budget of total reactive nitrogen (NO(y)) in the upper troposphere (8 - 12 km altitude). The median measured NO(y) mixing ratio was 425 parts per trillion by volume (pptv). Two different methods were used to measure HNO3: (1) the mist chamber technique and, (2) chemical ionization mass spectrometry. Two merged data sets using these HNO3 measurements were used to calculate NO(y) by summing the reactive nitrogen species (a combination of measured plus modeled results) and comparing the resultant values to measured NO(y) (gold catalytic reduction method). Both comparisons showed good agreement in the two quantities (slope greater than 0.9 and r(sup 2) greater than 0.9). Thus, the total reactive nitrogen budget in the upper troposphere over the North Atlantic can be explained in a general manner as a simple mixture of NO(x). (NO + NO2), HNO3, and PAN. Median values of NO(x)/NO(y) were approx. = 0.25, HNO3/NO(y) approx. = 0.35 and PAN/NO(y) approx. = 0.17. Particulate NO3 and alkyl nitrates together composed less than 10% of NO(y), while model estimated HNO4 averaged 12%.

  1. Measurements of Nitric Acid and Aerosol Species Aboard the NASA DC-8 Aircraft During the SASS Ozone and Nitrogen Oxide Experiment (SONEX)

    NASA Technical Reports Server (NTRS)

    Talbot, Robert W.; Dibb, Jack E.

    1999-01-01

    The SASS Ozone and Nitrogen Oxides Experiment (SONEX) over the North Atlantic during October/November 1997 offered an excellent opportunity to examine the budget of total reactive nitrogen (NO(sub y)) in the upper troposphere (8 - 12 km altitude). The median measured NO(sub y) mixing ratio was 425 parts per trillion by volume (pptv). Two different methods were used to measure HNO3: (1) the mist chamber technique and, (2) chemical ionization mass spectrometry. Two merged data sets using these HNO3 measurements were used to calculate NO(sub y) by summing the reactive nitrogen species (a combination of measured plus modeled results) and comparing the resultant values to measured NO(sub y) (gold catalytic reduction method). Both comparisons showed good agreement in the two quantities (slope > 0.9 and r(exp 2) > 0.9). Thus, the total reactive nitrogen budget in the upper troposphere over the North Atlantic can be explained in a general manner as a simple mixture of NO(sub x). (NO + NO2), HNO3, and PAN. Median values of NO(sub x)/NO(sub y) were approximately equal to 0.25, HNO3/NO(sub y) were approximately equal to 0.35 and Peroxyacetyl Nitrate (PAN)/NO(sub y) were approximately equal to 0. 17. Particulate NO3 and alkyl nitrates together composed <10 % of NO(sub y), while model estimated HNO4 averaged 12%.

  2. Forecasting Credit Hours.

    ERIC Educational Resources Information Center

    Bivin, David; Rooney, Patrick Michael

    1999-01-01

    This study used Tobit analysis to estimate retention probabilities and credit hours at two universities. Tobit was judged as appropriate for this problem because it recognizes the lower bound of zero on credit hours and incorporates this bound into parameter estimates and forecasts. Models are estimated for credit hours in a single year and…

  3. Cracking the Credit Hour

    ERIC Educational Resources Information Center

    Laitinen, Amy

    2012-01-01

    The basic currency of higher education--the credit hour--represents the root of many problems plaguing America's higher education system: the practice of measuring time rather than learning. "Cracking the Credit Hour" traces the history of this time-based unit, from the days of Andrew Carnegie to recent federal efforts to define a credit hour. If…

  4. Ozone variability

    NASA Astrophysics Data System (ADS)

    Duetsch, H. U.

    1983-09-01

    The annual and long-term variations in the atmospheric ozone layer were examined on the basis of 55 yr of data taken at Aroya, Switzerland and 25 yr of data gathered by the global ozone network. Attention was given to annual and biennial variations, which showed that the midlatitude peak concentration was affected by a quasi-biennial variation of the tropical stratospheric circulation. Smaller scale circulation patterns were dominant in the lower stratosphere, although an observed negative trend of the total ozone was equally distributed between the troposphere and 24 km altitude. The global ozone increase detected in the 1960s was possible due to general circulation alterations, but may also have been influenced by injection of NO(x) into the atmosphere during atomic bomb testing.

  5. CMAQ predictions of tropospheric ozone in the U.S. southwest: influence of lateral boundary and synoptic conditions.

    PubMed

    Shi, Chune; Fernando, H J S; Hyde, Peter

    2012-02-01

    Phoenix, Arizona, has been an ozone nonattainment area for the past several years and it remains so. Mitigation strategies call for improved modeling methodologies as well as understanding of ozone formation and destruction mechanisms during seasons of high ozone events. To this end, the efficacy of lateral boundary conditions (LBCs) based on satellite measurements (adjusted-LBCs) was investigated, vis-à-vis the default-LBCs, for improving the predictions of Models-3/CMAQ photochemical air quality modeling system. The model evaluations were conducted using hourly ground-level ozone and NO(2) concentrations as well as tropospheric NO(2) columns and ozone concentrations in the middle to upper troposphere, with the 'design' periods being June and July of 2006. Both included high ozone episodes, but the June (pre-monsoon) period was characterized by local thermal circulation whereas the July (monsoon) period by synoptic influence. Overall, improved simulations were noted for adjusted-LBC runs for ozone concentrations both at the ground-level and in the middle to upper troposphere, based on EPA-recommended model performance metrics. The probability of detection (POD) of ozone exceedances (>75ppb, 8-h averages) for the entire domain increased from 20.8% for the default-LBC run to 33.7% for the adjusted-LBC run. A process analysis of modeling results revealed that ozone within PBL during bulk of the pre-monsoon season is contributed by local photochemistry and vertical advection, while the contributions of horizontal and vertical advections are comparable in the monsoon season. The process analysis with adjusted-LBC runs confirms the contributions of vertical advection to episodic high ozone days, and hence elucidates the importance of improving predictability of upper levels with improved LBCs.

  6. 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.

  7. Application of dynamic linear regression to improve the skill of ensemble-based deterministic ozone forecasts

    SciTech Connect

    Pagowski, M O; Grell, G A; Devenyi, D; Peckham, S E; McKeen, S A; Gong, W; Monache, L D; McHenry, J N; McQueen, J; Lee, P

    2006-02-02

    Forecasts from seven air quality models and surface ozone data collected over the eastern USA and southern Canada during July and August 2004 provide a unique opportunity to assess benefits of ensemble-based ozone forecasting and devise methods to improve ozone forecasts. In this investigation, past forecasts from the ensemble of models and hourly surface ozone measurements at over 350 sites are used to issue deterministic 24-h forecasts using a method based on dynamic linear regression. Forecasts of hourly ozone concentrations as well as maximum daily 8-h and 1-h averaged concentrations are considered. It is shown that the forecasts issued with the application of this method have reduced bias and root mean square error and better overall performance scores than any of the ensemble members and the ensemble average. Performance of the method is similar to another method based on linear regression described previously by Pagowski et al., but unlike the latter, the current method does not require measurements from multiple monitors since it operates on individual time series. Improvement in the forecasts can be easily implemented and requires minimal computational cost.

  8. 50 CFR 20.23 - Shooting hours.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 50 Wildlife and Fisheries 8 2011-10-01 2011-10-01 false Shooting hours. 20.23 Section 20.23... PLANTS (CONTINUED) MIGRATORY BIRD HUNTING Taking § 20.23 Shooting hours. No person shall take migratory game birds except during the hours open to shooting as prescribed in subpart K of this part and...

  9. Activity of ozonated water and ozone against Staphylococcus aureus and Pseudomonas aeruginosa biofilms

    PubMed Central

    Bialoszewski, Dariusz; Pietruczuk-Padzik, Anna; Kalicinska, Agnieszka; Bocian, Ewa; Czajkowska, Magdalena; Bukowska, Bozena; Tyski, Stefan

    2011-01-01

    Summary Background The known bactericidal properties of ozone have not been checked in relation to its action on bacterial biofilms. This is especially true of ozonated fluids. The aim of this study was to investigate the bactericidal activity of ozonated water and that of a mixture of ozone and oxygen against biofilms. Material/Methods Eighteen clinical strains of Staphylococcus aureus and Pseudomonas aeruginosa exhibiting various levels of antibiotic sensitivity were investigated. Bacteria were cultured in biofilm form on polystyrene titration plates for periods of 2 to 72 hours. The biofilms formed in this way were exposed to in statu nascendi ozonated water produced in a prototype device that had been tested in clinical conditions, or to a mixture of oxygen and ozone generated in the same device. Live cells in the biofilm were stained with a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) bromide solution. The degree of reduction of viable bacteria following ozone exposure was determined. Results Ozonated water was found to be an effective bactericidal agent against biofilms after as little as 30 seconds of exposure, while the bactericidal activity of the ozone-oxygen solution was much lower. Prolongation of the duration of biofilm exposure to the gaseous disinfectant to 40 minutes led to a reduction in the viable cell count, which nevertheless remained high. Conclusions Unlike the ozone-oxygen mixture, ozonated water effectively destroys bacterial biofilms in vitro. PMID:22037737

  10. Respiratory and behavioral effects of ozone on a lizard and a frog.

    PubMed

    Mautz, William J; Dohm, Michael R

    2004-11-01

    Ozone at concentrations found in urban air pollution is known to have significant physiological effects on humans and other mammals. Exposure of the lizard, Sceloporus occidentalis, to 0.6 ppm ozone for 4 h at 25 degrees C induced 1.6 degrees C of behavioral hypothermia immediately following exposure, but selected body temperature recovered to control 35.3 degrees C the next day. Lizards exposed at 35 degrees C to 0.6 ppm ozone for 4 h selected body temperatures 1.9 degrees C below controls after exposure, and the behavioral hypothermic response persisted and increased to 3.3 degrees C the following day. Four-hour exposures of the frog, Pseudacris cadaverina, to 0.2 to 0.8 ppm ozone resulted in concentration-dependent alterations of respiration including depression of lung ventilation and oxygen consumption and the adoption of a low profile posture that reduced the exposed body surface. Ozone levels in wilderness habitats downwind of urban sources can potentially have stressful physiological effects on wildlife. Defensive physiological and behavioral reactions to ozone exposure may interfere with routine activities, and oxidant air pollution may be in part responsible for observed wildlife population declines. PMID:15556394

  11. The Interpretation of Sage II Ozone Measurements in the Lower Mesosphere.

    NASA Astrophysics Data System (ADS)

    Chu, Ding-Chong Allen

    SAGE II observations of ozone at sunrise and sunset (solar zenith angle = 90^circ) at approximately the same tropical latitude and on the same day exhibit larger concentrations at sunrise than at sunset between 55 km and 65 km altitude. Because of rapid conversion of atomic oxygen to ozone at sunset and the reverse at sunrise, the onion peeling assumption of constant ozone in the SAGE II retrievals is invalid in this altitude range. The observations are compared against predictions from a one-dimensional model by deriving simulated ozone profiles obtained by applying the onion peel procedure to model results. Good agreement between the observed and modeled sunrise/sunset ratios is then obtained. The results indicate that the SAGE II ozone retrievals overestimate by a factor of 1.3 at sunrise and 1.1 at sunset at 65 km (for example). Between 55 and 60 km altitude the Chapman reactions produce an adequate simulation of the sunrise and sunset ratio, but between 60 and 65 km this ratio is affected by the destruction of O_{ rm x} by HO_{rm x} during the first part of the night. SAGE II ozone profiles between 60 and 65 km altitude thus provide information on mesospheric HO_{rm x} chemistry not only through profiles averages but also through the sunrise/sunset ratio. The observations, for example, indicate an OH concentration at 65 km altitude in the tropics an hour after dark of approximately 8 times 10^6 cm ^{-3}.

  12. Ozonation by-products issued from the destruction of microorganisms present in wastewaters treated for reuse.

    PubMed

    Rojas-Valencia, M N; Orta-de-Velásquez, M T; Vaca-Mier, M; Franco, V

    2004-01-01

    This work demonstrates the reaction of ozone on the amino acids comprising the covering layer of resistant micro-organisms. A secondary aim was to check the byproducts generated when ozone was applied to synthetic samples (such as Vibrio cholerae NO 01 WFCC-449, Salmonella typhi ATTC-6539, faecal coliforms and Ascaris suum). The ozone was applied at a concentration of 18.4 mgO3/min at pH 3, for different lengths of time. In the case of bacteria, results showed that, at 8 minutes, the number was reduced to the level of the Official Mexican Standards set for treated water destined for irrigation purposes (1,000 MPN/100 mL). Excellent correlation coefficients (0.95 to 0.99) were obtained for microbial concentrations versus ozone contact time. Destruction times required for 100% removal of the initial bacteria population varied between 2 and 14 minutes, while Ascaris suum required 1 hour. When Gram-negative bacteria die due to the effects of ozone, cellular lysis and the liberation of endotoxins (biodegradable) were observed. The ozonation of amino acids in the shell of Ascaris suum eggs, leads to the formation of aldehydes, such as formaldehyde and acetaldehyde, in low concentrations (0.0003 and 0.0005 microg/mL respectively). These levels are not hazardous to human health.

  13. Seasonal variation in the acute effects of ozone on premature mortality among elderly Japanese.

    PubMed

    Ng, Chris Fook Sheng; Ueda, Kayo; Nitta, Hiroshi; Takeuchi, Ayano

    2013-10-01

    We conducted a multicity time-series study using monitoring data to assess seasonal patterns of short-term ozone-mortality association among elderly aged 65 years and over in Japan. Daily exposure to ambient ozone was computed using hourly measurements of photochemical oxidants available at multiple monitoring stations in each city. Effects of ozone on daily all-cause non-accidental, cardiovascular, and respiratory mortality were estimated using distributed lag linear models, controlling for confounding by temporal, day of the week, temperature, and flu epidemics. City-level effect estimates were combined using inverse variance meta-analysis. In spring and autumn, a 10-ppbv increase of daily maximum 8-h average ozone concentration in the previous 3 days was associated with 0.69 % (95 % confidence interval (CI): 0.27-1.10), 1.07 % (0.34-1.82), and 1.77 % (0.78-2.77) increases in daily all-cause, cardiovascular, and respiratory mortality, respectively. Forward displacement of respiratory mortality was large during the cold season despite lower ozone concentration. Results were generally independent of fine particulate matter and nitrogen dioxide. Findings suggest significant mortality effects of short-term ozone exposure among the elderly during the moderate season. Those with underlying respiratory diseases were susceptible, even during winter.

  14. 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.

  15. Surface ozone background in the United States: Canadian and Mexican pollution influences

    NASA Astrophysics Data System (ADS)

    Wang, Huiqun; Jacob, Daniel J.; Le Sager, Philippe; Streets, David G.; Park, Rokjin J.; Gilliland, Alice B.; van Donkelaar, A.

    We use a global chemical transport model (GEOS-Chem) with 1° × 1° horizontal resolution to quantify the effects of anthropogenic emissions from Canada, Mexico, and outside North America on daily maximum 8-hour average ozone concentrations in US surface air. Simulations for summer 2001 indicate mean North American and US background concentrations of 26 ± 8 ppb and 30 ± 8 ppb, as obtained by eliminating anthropogenic emissions in North America vs. in the US only. The US background never exceeds 60 ppb in the model. The Canadian and Mexican pollution enhancement averages 3 ± 4 ppb in the US in summer but can be occasionally much higher in downwind regions of the northeast and southwest, peaking at 33 ppb in upstate New York (on a day with 75 ppb total ozone) and 18 ppb in southern California (on a day with 68 ppb total ozone). The model is successful in reproducing the observed variability of ozone in these regions, including the occurrence and magnitude of high-ozone episodes influenced by transboundary pollution. We find that exceedances of the 75 ppb US air quality standard in eastern Michigan, western New York, New Jersey, and southern California are often associated with Canadian and Mexican pollution enhancements in excess of 10 ppb. Sensitivity simulations with 2020 emission projections suggest that Canadian pollution influence in the Northeast US will become comparable in magnitude to that from domestic power plants.

  16. Preparation and accurate measurement of pure ozone.

    PubMed

    Janssen, Christof; Simone, Daniela; Guinet, Mickaël

    2011-03-01

    Preparation of high purity ozone as well as precise and accurate measurement of its pressure are metrological requirements that are difficult to meet due to ozone decomposition occurring in pressure sensors. The most stable and precise transducer heads are heated and, therefore, prone to accelerated ozone decomposition, limiting measurement accuracy and compromising purity. Here, we describe a vacuum system and a method for ozone production, suitable to accurately determine the pressure of pure ozone by avoiding the problem of decomposition. We use an inert gas in a particularly designed buffer volume and can thus achieve high measurement accuracy and negligible degradation of ozone with purities of 99.8% or better. The high degree of purity is ensured by comprehensive compositional analyses of ozone samples. The method may also be applied to other reactive gases. PMID:21456766

  17. Ozone transport commission developments

    SciTech Connect

    Joyce, K.M.

    1995-08-01

    On September 27, 1994, the states of the Ozone Transport Commission (OTC) signed an important memorandum of understanding (MOU) agreeing to develop a regional strategy for controlling stationary sources of nitrogen oxide emissions. Specifically, the states of the Ozone Transport Region, OTR, agreed to propose regulations for the control of NOx emissions from boilers and other indirect heat exchangers with a maximum gross heat input rate of at least 250 million BTU per hour. The Ozone Transport Region was divided into Inner, Outer and Northern Zones. States in the Outer Zone agreed to reduce NOx emissions by 55%. States in the Inner Zone agreed to reduce NOx emissions 65%. Facilities in both zones have the option to emit NOx at a rate no greater than 0.2 pounds per million Btu by May 1, 1999. This option provides fairness for the gas-fired plants which already have relatively low NOx emissions. Additionally, States in the Inner and Outer Zones agreed to reduce their NOx emissions by 75% or to emit NOx at a rate no greater than 0.15 pounds per million BTU by May 1, 2003. The Northern Zone States agree to reduce their rate of NOx emissions by 55% from base year levels by May 1, 2003, or to emit NOx at a rate no greater than 0.2 pounds per million BTU. As part of this MOU, States also agreed to develop a regionwide trading mechanism to provide a cost-effective mechanism for implementing the reductions.

  18. Evaluation of Upper-Tropospheric and Lower-Stratospheric Ozone Profiles from a Global Ozone Data Assimilation System

    NASA Technical Reports Server (NTRS)

    Rood, Richard B.; Stajner, Ivanka; Phelps, Carrie; Einaudi, Franco (Technical Monitor)

    2000-01-01

    The Data Assimilation Office at NASA's Goddard Space Flight Center provides global 3D ozone fields at six-hour time intervals. Data from Total Ozone Mapping Spectrometer (TOMS) and the Solar Backscatter Ultraviolet (SBUV) instrument are used in the assimilation. TOMS provides total column information and SBUV provides profile information, primarily above the ozone peak. Information below the ozone peak comes from the model. This paper will explore the realism of the assimilated ozone in the upper troposphere and lower stratosphere through validation with ozonesondes, Halogen Occultation Experiment (HALOE), and Polar Ozone and Aerosol Measurement (POAM) observations. This work is in preparation of using the assimilated ozone in the radiative calculation for the meteorological assimilation as well as in the derivation of tropospheric ozone.

  19. The Impact of Meteorology on Ozone Levels in the Lake Tahoe Basin

    NASA Astrophysics Data System (ADS)

    Theiss, Sandra

    The Lake Tahoe Basin is located on the California-Nevada border and occasionally experiences elevated levels of ozone exceeding the 70 ppb California Air Resources Board (CARB) ambient air quality standard (8-hour average). Previous studies indicate that both the local generation of ozone in the Basin and long-range transport from out-of-Basin sources are important in contributing to ozone exceedances, but little is known about the impact of meteorology on the distribution of ozone source regions. In order to develop a better understanding of the factors affecting ozone levels and sources in the Lake Tahoe Basin, this study combines observational data from a 2010 and 2012 summer field campaigns, HYSPLIT back trajectories, and WRF model output to examine the meteorological influences of ozone transport in the topographically complex Lake Tahoe Basin. Findings from the field work portions of this study include enhanced background ozone levels at higher elevations, the local circulation pattern of lake breezes occurring at Lake level sites, and an indication that ozone precursors are coming off the Lake. Our analysis also showed that if transport of ozone does occur, it is more likely to come from the San Joaquin Valley to the south rather than originate in the large cities to the west, such as Sacramento and San Francisco. Analysis of modeled PBL schemes as compared with observational data showed that the ACM2 PBL scheme best represented the geographical domain. The ACM2 PBL scheme was then used to show wind circulation patterns in the Lake Tahoe Basin and concluded that there is decent vertical mixing over the Basin and no indication of ozone transport from the west however some indication of transport from the east. Overall this study concludes that transport from the west is less significant than transport from the south and east, and that transport only influences ozone values at higher elevations. Within the Basin itself (at lower elevations), local factors

  20. Ozone concentrations in air flowing into New York State

    NASA Astrophysics Data System (ADS)

    Aleksic, Nenad; Kent, John; Walcek, Chris

    2016-09-01

    Ozone (O3) concentrations measured at Pinnacle State Park (PSPNY), very close to the southern border of New York State, are used to estimate concentrations in air flowing into New York. On 20% of the ozone season (April-September) afternoons from 2004 to 2015, mid-afternoon 500-m back trajectories calculated from PSPNY cross New York border from the south and spend less than three hours in New York State, in this area of negligible local pollution emissions. One-hour (2p.m.-3p.m.) O3 concentrations during these inflowing conditions were 46 ± 13 ppb, and ranged from a minimum of 15 ppb to a maximum of 84 ppb. On average during 2004-2015, each year experienced 11.8 days with inflowing 1-hr O3 concentrations exceeding 50 ppb, 4.3 days with O3 > 60 ppb, and 1.5 days had O3 > 70 ppb. During the same period, 8-hr average concentrations (10a.m. to 6p.m.) exceeded 50 ppb on 10.0 days per season, while 3.9 days exceeded 60 ppb, and 70 ppb was exceeded 1.2 days per season. Two afternoons of minimal in-state emission influences with high ozone concentrations were analyzed in more detail. Synoptic and back trajectory analysis, including comparison with upwind ozone concentrations, indicated that the two periods were characterized as photo-chemically aged air containing high inflowing O3 concentrations most likely heavily influenced by pollution emissions from states upwind of New York including Pennsylvania, Tennessee, West Virginia, and Ohio. These results suggest that New York state-level attempts to comply with National Ambient Air Quality Standards by regulating in-state O3 precursor NOx and organic emissions would be very difficult, since air frequently enters New York State very close to or in excess of Federal Air Quality Standards.

  1. 12 hour shifts the Nambour Hospital experience.

    PubMed

    2007-08-01

    Union members have a lengthy history of campaigning for fair working hours and conditions. The success of such campaigns has led to the implementation of the eight hour working day and the 40 hour and then 38 hour week as industrial standards. More recently though, calls for greater flexibility in their shift arrangements by nurses at Nambour Hospital have led to a voluntary 12 hour shift being implemented in their Intensive Care Unit. While union members are protective of their hard won gains in achieving reduced working hours through the 8 hour day--ICU nurses at Nambour Hospital say the voluntary 12 hour shift initiative goes a way in addressing their work/life balance issues.

  2. Ozone-Induced Type 2 Immunity in Nasal Airways. Development and Lymphoid Cell Dependence in Mice.

    PubMed

    Ong, Chee Bing; Kumagai, Kazuyoshi; Brooks, Phillip T; Brandenberger, Christina; Lewandowski, Ryan P; Jackson-Humbles, Daven N; Nault, Rance; Zacharewski, Timothy R; Wagner, James G; Harkema, Jack R

    2016-03-01

    Inhalation exposures to ozone commonly encountered in photochemical smog cause airway injury and inflammation. Elevated ambient ozone concentrations have been epidemiologically associated with nasal airway activation of neutrophils and eosinophils. In the present study, we elucidated the temporal onset and lymphoid cell dependency of eosinophilic rhinitis and associated epithelial changes in mice repeatedly exposed to ozone. Lymphoid cell-sufficient C57BL/6 mice were exposed to 0 or 0.5 parts per million (ppm) ozone for 1, 2, 4, or 9 consecutive weekdays (4 h/d). Lymphoid cell-deficient, Rag2(-/-)Il2rg(-/-) mice were similarly exposed for 9 weekdays. Nasal tissues were taken at 2 or 24 hours after exposure for morphometric and gene expression analyses. C57BL/6 mice exposed to ozone for 1 day had acute neutrophilic rhinitis, with airway epithelial necrosis and overexpression of mucosal Ccl2 (MCP-1), Ccl11 (eotaxin), Cxcl1 (KC), Cxcl2 (MIP-2), Hmox1, Il1b, Il5, Il6, Il13, and Tnf mRNA. In contrast, 9-day ozone exposure elicited type 2 immune responses in C57BL/6 mice, with mucosal mRNA overexpression of Arg1, Ccl8 (MCP-2), Ccl11, Chil4 (Ym2), Clca1 (Gob5), Il5, Il10, and Il13; increased density of mucosal eosinophils; and nasal epithelial remodeling (e.g., hyperplasia/hypertrophy, mucous cell metaplasia, hyalinosis, and increased YM1/YM2 proteins). Rag2(-/-)Il2rg(-/-) mice exposed to ozone for 9 days, however, had no nasal pathology or overexpression of transcripts related to type 2 immunity. These results provide a plausible paradigm for the activation of eosinophilic inflammation and type 2 immunity found in the nasal airways of nonatopic individuals subjected to episodic exposures to high ambient ozone.

  3. Individuals with increased inflammatory response to ozone demonstrate muted signaling of immune cell trafficking pathways

    PubMed Central

    2012-01-01

    Background Exposure to ozone activates innate immune function and causes neutrophilic (PMN) airway inflammation that in some individuals is robustly elevated. The interplay between immuno-inflammatory function and genomic signaling in those with heightened inflammatory responsiveness to ozone is not well understood. Objectives Determine baseline predictors and post exposure discriminators for the immuno-inflammatory response to ozone in inflammatory responsive adult volunteers. Methods Sputum induction was performed on 27 individuals before and after a two hour chamber exposure to 0.4 ppm ozone. Subjects were classified as inflammatory responders or non-responders to ozone based on their PMN response. Innate immune function, inflammatory cell and cytokine modulation and transcriptional signaling pathways were measured in sputum. Results Post exposure, responders showed activated innate immune function (CD16: 31,004 MFI vs 8988 MFI; CD11b: 44,986 MFI vs 24,770 MFI; CD80: 2236 MFI vs 1506 MFI; IL-8: 37,603 pg/ml vs 2828 pg/ml; and IL-1β: 1380 pg/ml vs 318 pg/ml) with muted signaling of immune cell trafficking pathways. In contrast, non-responders displayed decreased innate immune activity (CD16, CD80; phagocytosis: 2 particles/PMN vs 4 particles/PMN) post exposure that was accompanied by a heightened signaling of immune cell trafficking pathways. Conclusions Inflammatory responsive and non responsive individuals to ozone show an inverse relationship between immune cell trafficking and immuno-inflammatory functional responses to ozone. These distinct genomic signatures may further our understanding about ozone-induced morbidity in individuals with different levels of inflammatory responsiveness. PMID:23033980

  4. Ozone-Induced Type 2 Immunity in Nasal Airways. Development and Lymphoid Cell Dependence in Mice.

    PubMed

    Ong, Chee Bing; Kumagai, Kazuyoshi; Brooks, Phillip T; Brandenberger, Christina; Lewandowski, Ryan P; Jackson-Humbles, Daven N; Nault, Rance; Zacharewski, Timothy R; Wagner, James G; Harkema, Jack R

    2016-03-01

    Inhalation exposures to ozone commonly encountered in photochemical smog cause airway injury and inflammation. Elevated ambient ozone concentrations have been epidemiologically associated with nasal airway activation of neutrophils and eosinophils. In the present study, we elucidated the temporal onset and lymphoid cell dependency of eosinophilic rhinitis and associated epithelial changes in mice repeatedly exposed to ozone. Lymphoid cell-sufficient C57BL/6 mice were exposed to 0 or 0.5 parts per million (ppm) ozone for 1, 2, 4, or 9 consecutive weekdays (4 h/d). Lymphoid cell-deficient, Rag2(-/-)Il2rg(-/-) mice were similarly exposed for 9 weekdays. Nasal tissues were taken at 2 or 24 hours after exposure for morphometric and gene expression analyses. C57BL/6 mice exposed to ozone for 1 day had acute neutrophilic rhinitis, with airway epithelial necrosis and overexpression of mucosal Ccl2 (MCP-1), Ccl11 (eotaxin), Cxcl1 (KC), Cxcl2 (MIP-2), Hmox1, Il1b, Il5, Il6, Il13, and Tnf mRNA. In contrast, 9-day ozone exposure elicited type 2 immune responses in C57BL/6 mice, with mucosal mRNA overexpression of Arg1, Ccl8 (MCP-2), Ccl11, Chil4 (Ym2), Clca1 (Gob5), Il5, Il10, and Il13; increased density of mucosal eosinophils; and nasal epithelial remodeling (e.g., hyperplasia/hypertrophy, mucous cell metaplasia, hyalinosis, and increased YM1/YM2 proteins). Rag2(-/-)Il2rg(-/-) mice exposed to ozone for 9 days, however, had no nasal pathology or overexpression of transcripts related to type 2 immunity. These results provide a plausible paradigm for the activation of eosinophilic inflammation and type 2 immunity found in the nasal airways of nonatopic individuals subjected to episodic exposures to high ambient ozone. PMID:26203683

  5. Mars Ozone Mapping with MAVEN IUVS

    NASA Astrophysics Data System (ADS)

    Lefèvre, F.; Montmessin, F.; Schneider, N. M.; Deighan, J.; Jain, S.; Stewart, I. F.; Stiepen, A.; Chaffin, M.; McClintock, W. E.; Lo, D.; Clarke, J. T.; Holsclaw, G.; Jakosky, B. M.

    2015-12-01

    Ozone (O3) on Mars is a product of the CO2 photolysis by ultraviolet radiation. It is destroyed with a timescale of less than ~1 hour during the day by the H, OH, and HO2 radicals. This tight coupling between O3 and HOx species makes ozone a sensitive tracer of the odd hydrogen chemistry that stabilizes the CO2 atmosphere of Mars, and ozone measurements offer a powerful constraint for photochemical models. Ozone is also expected to be anti-correlated to water vapour, the source of hydrogen radicals HOx. At high latitudes in winter, the absence of H2O prevents the production of HOx and the chemical lifetime of ozone may increase up to several days. In these conditions, the ozone column abundance usually reaches its largest values of the Martian year and ozone turns into a measurable tracer of the polar vortex dynamics. The Imaging Ultraviolet Spectrograph (IUVS) is one of nine science instruments aboard the Mars Atmosphere and Volatile and Evolution (MAVEN) spacecraft. In the apoapse imaging phase, the spacecraft motion carries the IUVS lines-of-sight across the Martian disk while the scan mirror is used to make transverse swaths. This observation mode allows mapping the ozone vertically-integrated column from its signature in the solar ultraviolet flux backscattered by the surface and the atmosphere. This paper will present an overview of the first year of ozone mapping by IUVS. We will describe in particular the last Mars northern winter (2015) when the largest ozone columns have been observed since the beginning of the MAVEN mission. The data will be compared to prior Earth-based observations and to the SPICAM and MARCI ozone datasets. We will also test our quantitative understanding of the Martian ozone by comparing the IUVS observations to our three-dimensional model with photochemistry.

  6. Correlation of DIAL Ozone Observations with Lightning

    NASA Technical Reports Server (NTRS)

    Peterson, Harold S.; Kuang, Shi; Koshak, William J.; Newchurch, Mike

    2014-01-01

    The purpose of this project is to see whether ozone maxima measured by the DIfferential Absorption Lidar (DIAL) instrument in Huntsville, AL may be traced back to lightning events occurring 24-48 hours beforehand. The methodology is to start with lidar measurements of ozone from DIAL. The HYbrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model is then used to determine the origin of these ozone maxima 24-48 hours prior. Data from the National Lightning Detection Network (NLDN) are used to examine the presence/absence of lightning along the trajectory. This type of analysis suggests that lightning-produced NOx may be responsible for some of the ozone maxima over Huntsville.

  7. Correlation of DIAL Ozone Observations with Lightning

    NASA Technical Reports Server (NTRS)

    Peterson, Harold; Kuang, Shi; Koshak, William; Newchurch, Michael

    2013-01-01

    The purpose of this project is to see whether ozone maxima measured by the DIfferential Absorption Lidar (DIAL) instrument in Huntsville, AL may be traced back to lightning events occurring 24- 48 hours beforehand. The methodology is to start with lidar measurements of ozone from DIAL as well as ozonesonde measurements. The HYbrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model is then used to determine the origin of these ozone maxima 24-48 hours prior. Data from the National Lightning Detection Network (NLDN) are used to examine the presence/absence of lightning along the trajectory. This type of analysis suggests that lightning-produced NOx may be responsible for some of the ozone maxima over Huntsville.

  8. 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…

  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. Assessing control strategies for ground level ozone

    NASA Astrophysics Data System (ADS)

    Sule, Neelesh Vijay

    2009-12-01

    combination of targeted control strategies that brings the region into attainment for the 8-hour ozone. Each day was optimized individually in sequence. In order to demonstrate applicability of the DMF 5 days (August 15, 16, 17, 18 and 19) of the episode were optimized. Although the optimization identified the key sources, time periods, and control strategies, the existing controls on these sources were not adequate to bring the region in attainment. Further reductions at these sources beyond the existing list of TCEQ/NCTCOG control strategies were required. Further modifications in the DMF for DFW were suggested to improve its performance.

  11. 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)

  12. Ozone crisis

    SciTech Connect

    Roan, S.

    1989-01-01

    The author presents an account of the depletion of the atmosphere's ozone layer since the discovery of the phenomenon 15 years ago. The book recounts the flight to ban chlorofluorocarbons (CFC's) and describes the science, the people, and the politics involved, up to the March 1988 international treaty restricting CFC production. It surveys the media's coverage, describes the struggle for remedies, and offers a prognosis for the future.

  13. Ozone dose-response relationships for spring oilseed rape and broccoli

    NASA Astrophysics Data System (ADS)

    De Bock, Maarten; Op de Beeck, Maarten; De Temmerman, Ludwig; Guisez, Yves; Ceulemans, Reinhart; Vandermeiren, Karine

    2011-03-01

    Tropospheric ozone is an important air pollutant with known detrimental effects for several crops. Ozone effects on seed yield, oil percentage, oil yield and 1000 seed weight were examined for spring oilseed rape ( Brassica napus cv. Ability). For broccoli ( Brassica oleracea L. cv. Italica cv. Monaco) the effects on fresh marketable weight and total dry weight were studied. Current ozone levels were compared with an increase of 20 and 40 ppb during 8 h per day, over the entire growing season. Oilseed rape seed yield was negatively correlated with ozone dose indices calculated from emergence until harvest. This resulted in an R2 of 0.24 and 0.26 ( p < 0.001) for the accumulated hourly O 3 exposure over a threshold of 40 ppb (AOT40) and the phytotoxic ozone dose above a threshold of 6 nmol m -2 s -1 (POD 6) respectively. Estimated critical levels, above which 5% yield reduction is expected, were 3.7 ppm h and 4.4 mmol m -2 respectively. Our results also confirm that a threshold value of 6 nmol s -1 m -2 projected leaf area, as recommended for agricultural crops (UNECE, Mills, 2004), can indeed be applied for spring oilseed rape. The reduction of oilseed rape yield showed the highest correlation with the ozone uptake during the vegetative growth stage: when only the first 47 days after emergence were used to calculate POD 6, R2 values increased up to 0.476 or even 0.545 when the first 23 days were excluded. The highest ozone treatments, corresponding to the future ambient level by 2100 (IPCC, Meehl et al., 2007), led to a reduction of approximately 30% in oilseed rape seed yield in comparison to the current ozone concentrations. Oil percentage was also significantly reduced in response to ozone ( p < 0.001). As a consequence oil yield was even more severely affected by elevated ozone exposure compared to seed yield: critical levels for oil yield dropped to 3.2 ppm h and 3.9 mmol m -2. For broccoli the applied ozone doses had no effect on yield.

  14. Statistical evaluation of the impact of shale gas activities on ozone pollution in North Texas.

    PubMed

    Ahmadi, Mahdi; John, Kuruvilla

    2015-12-01

    Over the past decade, substantial growth in shale gas exploration and production across the US has changed the country's energy outlook. Beyond its economic benefits, the negative impacts of shale gas development on air and water are less well known. In this study the relationship between shale gas activities and ground-level ozone pollution was statistically evaluated. The Dallas-Fort Worth (DFW) area in north-central Texas was selected as the study region. The Barnett Shale, which is one the most productive and fastest growing shale gas fields in the US, is located in the western half of DFW. Hourly meteorological and ozone data were acquired for fourteen years from monitoring stations established and operated by the Texas Commission on Environmental Quality (TCEQ). The area was divided into two regions, the shale gas region (SGR) and the non-shale gas (NSGR) region, according to the number of gas wells in close proximity to each monitoring site. The study period was also divided into 2000-2006 and 2007-2013 because the western half of DFW has experienced significant growth in shale gas activities since 2007. An evaluation of the raw ozone data showed that, while the overall trend in the ozone concentration was down over the entire region, the monitoring sites in the NSGR showed an additional reduction of 4% in the annual number of ozone exceedance days than those in the SGR. Directional analysis of ozone showed that the winds blowing from areas with high shale gas activities contributed to higher ozone downwind. KZ-filtering method and linear regression techniques were used to remove the effects of meteorological variations on ozone and to construct long-term and short-term meteorologically adjusted (M.A.) ozone time series. The mean value of all M.A. ozone components was 8% higher in the sites located within the SGR than in the NSGR. These findings may be useful for understanding the overall impact of shale gas activities on the local and regional ozone

  15. Statistical evaluation of the impact of shale gas activities on ozone pollution in North Texas.

    PubMed

    Ahmadi, Mahdi; John, Kuruvilla

    2015-12-01

    Over the past decade, substantial growth in shale gas exploration and production across the US has changed the country's energy outlook. Beyond its economic benefits, the negative impacts of shale gas development on air and water are less well known. In this study the relationship between shale gas activities and ground-level ozone pollution was statistically evaluated. The Dallas-Fort Worth (DFW) area in north-central Texas was selected as the study region. The Barnett Shale, which is one the most productive and fastest growing shale gas fields in the US, is located in the western half of DFW. Hourly meteorological and ozone data were acquired for fourteen years from monitoring stations established and operated by the Texas Commission on Environmental Quality (TCEQ). The area was divided into two regions, the shale gas region (SGR) and the non-shale gas (NSGR) region, according to the number of gas wells in close proximity to each monitoring site. The study period was also divided into 2000-2006 and 2007-2013 because the western half of DFW has experienced significant growth in shale gas activities since 2007. An evaluation of the raw ozone data showed that, while the overall trend in the ozone concentration was down over the entire region, the monitoring sites in the NSGR showed an additional reduction of 4% in the annual number of ozone exceedance days than those in the SGR. Directional analysis of ozone showed that the winds blowing from areas with high shale gas activities contributed to higher ozone downwind. KZ-filtering method and linear regression techniques were used to remove the effects of meteorological variations on ozone and to construct long-term and short-term meteorologically adjusted (M.A.) ozone time series. The mean value of all M.A. ozone components was 8% higher in the sites located within the SGR than in the NSGR. These findings may be useful for understanding the overall impact of shale gas activities on the local and regional ozone

  16. Sunrise ozone destruction found in the sub-tropical marine boundary layer

    NASA Astrophysics Data System (ADS)

    Nagao, Ippei; Matsumoto, Kiyoshi; Tanaka, Hiroshi

    A new mechanism of ozone loss is found in the sub-tropical marine boundary layer over the north Pacific. This ozone destruction occurs just after sunrise (hereafter Sunrise Ozone Destruction, SOD) and is commonly found throughout the year. SOD is a predominant ozone loss mechanism in winter, which takes place after sunrise in a few hours with 1∼2 ppbv of ozone depletion for 40∼50 ppbv of background ozone, while, in summer, SOD is weaker than in winter with small ozone depletion for 10∼20 ppbv of background ozone. In summer, daytime ozone destruction (hereafter, DOD) associated with UV photolysis and subsequent HOx reaction is more active. Since DOD is not active in early morning, SOD should be a new ozone loss mechanism. After demonstrating the observational findings, halogen chemistry associated with sea-salt aerosols is described as a possible mechanism.

  17. Tropospheric ozone production regions and the intercontinental origins of surface ozone over Europe

    NASA Astrophysics Data System (ADS)

    Derwent, Richard G.; Utembe, Steven R.; Jenkin, Michael E.; Shallcross, Dudley E.

    2015-07-01

    Ozone tagged labelling schemes have been implemented in a global Lagrangian chemistry-transport model to identify the intercontinental origins of surface ozone in Europe. Stratosphere-troposphere exchange gave rise to between 3 and 5 ppb across Europe, whereas the mid-latitudes of the Middle East, Asia and the Pacific Ocean region contributed 6-8 ppb. Surface ozone levels of 10-16 ppb were associated with the mid-latitudes of North America and the North Atlantic Ocean regions. Appreciable intercontinental ozone production occurred downwind of continental regions and above the surface layer. Intercontinental ozone formation and transport from tropical regions contributed about 4 ppb and was much less efficient compared with that from mid-latitudes. There were approaching 60 chemical processes driving intercontinental ozone formation, of which the HO2 + NO, CH3O2 + NO and CH3COO2 + NO reactions were the most important. Ozone production appeared to be driven by OH oxidation of secondary reaction products rather than the oxidation of primary emitted VOCs. The largest intercontinental ozone contributions amounted to about 20 ppb from North America to European baseline stations, 14 ppb from Asia to North American baseline stations and 10 ppb from Asia to European baseline stations. It is possible that changing intercontinental ozone production and transport could have led to seasonal ozone trends and shifts in seasonal cycles at northern hemisphere mid-latitude baseline ozone monitoring stations.

  18. 21 CFR 801.415 - Maximum acceptable level of ozone.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... Conference of Governmental Industrial Hygienists. (e) The method and apparatus specified in 40 CFR part 50... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Maximum acceptable level of ozone. 801.415 Section... level of ozone. (a) Ozone is a toxic gas with no known useful medical application in...

  19. 21 CFR 801.415 - Maximum acceptable level of ozone.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... Conference of Governmental Industrial Hygienists. (e) The method and apparatus specified in 40 CFR part 50... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Maximum acceptable level of ozone. 801.415 Section... level of ozone. (a) Ozone is a toxic gas with no known useful medical application in...

  20. 21 CFR 801.415 - Maximum acceptable level of ozone.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... Conference of Governmental Industrial Hygienists. (e) The method and apparatus specified in 40 CFR part 50... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Maximum acceptable level of ozone. 801.415 Section... level of ozone. (a) Ozone is a toxic gas with no known useful medical application in...

  1. MBBR evaluation for oil refinery wastewater treatment, with post-ozonation and BAC, for wastewater reuse.

    PubMed

    Schneider, E E; Cerqueira, A C F P; Dezotti, M

    2011-01-01

    This work evaluated the performance of a Moving Bed Biofilm Reactor (MBBR) in the treatment of an oil refinery wastewater. Also, it investigated the possibility of reuse of the MBBR effluent, after ozonation in series with a biological activated carbon (BAC) column. The best performance of the MBBR was achieved with a hydraulic retention time (HRT) of 6 hours, employing a bed to bioreactor volume ratio (V(B)/V(R)) of 0.6. COD and N-NH₄(+) MBBR effluent concentrations ranged from 40 to 75 mg L⁻¹ (removal efficiency of 69-89%) and 2 to 6 mg L⁻¹ (removal efficiency of 45-86%), respectively. Ozonation carried out for 15 min with an ozone concentration of 5 mg L⁻¹ was able to improve the treated wastewater biodegradability. The treatment performance of the BAC columns was practically the same for ozonated and non ozonated MBBR effluents. The dissolved organic carbon (DOC) content of the columns of the activated carbon columns (CAG) was in the range of 2.1-3.8 mg L⁻¹, and the corresponding DOC removal efficiencies were comprised between 52 and 75%. The effluent obtained at the end of the proposed treatment presented a quality, which meet the requirements for water reuse in the oil refinery.

  2. Who is more affected by ozone pollution? A systematic review and meta-analysis.

    PubMed

    Bell, Michelle L; Zanobetti, Antonella; Dominici, Francesca

    2014-07-01

    Ozone is associated with adverse health; however, less is known about vulnerable/sensitive populations, which we refer to as sensitive populations. We systematically reviewed epidemiologic evidence (1988-2013) regarding sensitivity to mortality or hospital admission from short-term ozone exposure. We performed meta-analysis for overall associations by age and sex; assessed publication bias; and qualitatively assessed sensitivity to socioeconomic indicators, race/ethnicity, and air conditioning. The search identified 2,091 unique papers, with 167 meeting inclusion criteria (73 on mortality and 96 on hospitalizations and emergency department visits, including 2 examining both mortality and hospitalizations). The strongest evidence for ozone sensitivity was for age. Per 10-parts per billion increase in daily 8-hour ozone concentration, mortality risk for younger persons, at 0.60% (95% confidence interval (CI): 0.40, 0.80), was statistically lower than that for older persons, at 1.27% (95% CI: 0.76, 1.78). Findings adjusted for publication bias were similar. Limited/suggestive evidence was found for higher associations among women; mortality risks were 0.39% (95% CI: -0.22, 1.00) higher than those for men. We identified strong evidence for higher associations with unemployment or lower occupational status and weak evidence of sensitivity for racial/ethnic minorities and persons with low education, in poverty, or without central air conditioning. Findings show that some populations, especially the elderly, are particularly sensitive to short-term ozone exposure. PMID:24872350

  3. MBBR evaluation for oil refinery wastewater treatment, with post-ozonation and BAC, for wastewater reuse.

    PubMed

    Schneider, E E; Cerqueira, A C F P; Dezotti, M

    2011-01-01

    This work evaluated the performance of a Moving Bed Biofilm Reactor (MBBR) in the treatment of an oil refinery wastewater. Also, it investigated the possibility of reuse of the MBBR effluent, after ozonation in series with a biological activated carbon (BAC) column. The best performance of the MBBR was achieved with a hydraulic retention time (HRT) of 6 hours, employing a bed to bioreactor volume ratio (V(B)/V(R)) of 0.6. COD and N-NH₄(+) MBBR effluent concentrations ranged from 40 to 75 mg L⁻¹ (removal efficiency of 69-89%) and 2 to 6 mg L⁻¹ (removal efficiency of 45-86%), respectively. Ozonation carried out for 15 min with an ozone concentration of 5 mg L⁻¹ was able to improve the treated wastewater biodegradability. The treatment performance of the BAC columns was practically the same for ozonated and non ozonated MBBR effluents. The dissolved organic carbon (DOC) content of the columns of the activated carbon columns (CAG) was in the range of 2.1-3.8 mg L⁻¹, and the corresponding DOC removal efficiencies were comprised between 52 and 75%. The effluent obtained at the end of the proposed treatment presented a quality, which meet the requirements for water reuse in the oil refinery. PMID:21245566

  4. 16 CFR 0.3 - Hours.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Hours. 0.3 Section 0.3 Commercial Practices FEDERAL TRADE COMMISSION ORGANIZATION, PROCEDURES AND RULES OF PRACTICE ORGANIZATION § 0.3 Hours. Principal and field offices are open on each business day from 8:30 a.m. to 5 p.m....

  5. 16 CFR 0.3 - Hours.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 1 2011-01-01 2011-01-01 false Hours. 0.3 Section 0.3 Commercial Practices FEDERAL TRADE COMMISSION ORGANIZATION, PROCEDURES AND RULES OF PRACTICE ORGANIZATION § 0.3 Hours. Principal and field offices are open on each business day from 8:30 a.m. to 5 p.m....

  6. 16 CFR 0.3 - Hours.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 1 2014-01-01 2014-01-01 false Hours. 0.3 Section 0.3 Commercial Practices FEDERAL TRADE COMMISSION ORGANIZATION, PROCEDURES AND RULES OF PRACTICE ORGANIZATION § 0.3 Hours. Principal and field offices are open on each business day from 8:30 a.m. to 5 p.m....

  7. 16 CFR 0.3 - Hours.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 1 2013-01-01 2013-01-01 false Hours. 0.3 Section 0.3 Commercial Practices FEDERAL TRADE COMMISSION ORGANIZATION, PROCEDURES AND RULES OF PRACTICE ORGANIZATION § 0.3 Hours. Principal and field offices are open on each business day from 8:30 a.m. to 5 p.m....

  8. 16 CFR 0.3 - Hours.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 1 2012-01-01 2012-01-01 false Hours. 0.3 Section 0.3 Commercial Practices FEDERAL TRADE COMMISSION ORGANIZATION, PROCEDURES AND RULES OF PRACTICE ORGANIZATION § 0.3 Hours. Principal and field offices are open on each business day from 8:30 a.m. to 5 p.m....

  9. Stratospheric ozone effects on temperature.

    PubMed

    Reck, R A

    1976-05-01

    Calculated surface temperature changes, DeltaT(8), due to stratospheric ozone depletion (at 35 degrees N latitude in April) are less than previously estimated and range between -0.6 and +0.9 degrees K. The sign of DeltaT(8), is determined by the surface albedo and the presence or absence of a low-lying particulate layer (heating with particles, cooling without particles). The calculations indicate that a 90 percent stratospheric ozone depletion does not cause the temperature inversion at the tropopause to vanish, although it is weakened substantially.

  10. Biochemical Plant Responses to Ozone 1

    PubMed Central

    Langebartels, Christian; Kerner, Kristina; Leonardi, Silvio; Schraudner, Martina; Trost, Monika; Heller, Werner; Sandermann, Heinrich

    1991-01-01

    Polyamine metabolism was examined in tobacco (Nicotiana tabacum L.) exposed to a single ozone treatment (5 or 7 hours) and then postcultivated in pollutant-free air. The levels of free and conjugated putrescine were rapidly increased in the ozone-tolerant cultivar Bel B and remained high for 3 days. This accumulation was preceded by a transient rise of l-arginine decar-boxylase (ADC, EC 4.1.1.19) activity. The ozone-sensitive cultivar Bel W3 showed a rapid production of ethylene and high levels of 1-aminocyclopropane-1-carboxylic acid after 1 to 2 hours of exposure. Induction of putrescine levels and ADC activity was weak in this cultivar and was observed when necrotic lesions developed. Leaf injury occurred in both lines when the molar ratio of putrescine to 1-aminocyclopropane-1-carboxylic acid or ethylene fell short of a certain threshold value. Monocaffeoyl-putrescine, an effective scavenger for oxyradicals, was detected in the apo-plastic fluid of the leaves of cv Bel B and increased upon exposure to ozone. This extracellular localization could allow scavenging of ozone-derived oxyradicals at the first site of their generation. Induction of either polyamine or ethylene pathways may represent a control mechanism for inhibition or promotion of lesion formation and thereby contribute to the disposition of plants for ozone tolerance. PMID:16668067

  11. 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

  12. Detection of stratospheric ozone intrusions by windprofiler radars.

    PubMed

    Hocking, W K; Carey-Smith, T; Tarasick, D W; Argall, P S; Strong, K; Rochon, Y; Zawadzki, I; Taylor, P A

    2007-11-01

    Stratospheric ozone attenuates harmful ultraviolet radiation and protects the Earth's biosphere. Ozone is also of fundamental importance for the chemistry of the lowermost part of the atmosphere, the troposphere. At ground level, ozone is an important by-product of anthropogenic pollution, damaging forests and crops, and negatively affecting human health. Ozone is critical to the chemical and thermal balance of the troposphere because, via the formation of hydroxyl radicals, it controls the capacity of tropospheric air to oxidize and remove other pollutants. Moreover, ozone is an important greenhouse gas, particularly in the upper troposphere. Although photochemistry in the lower troposphere is the major source of tropospheric ozone, the stratosphere-troposphere transport of ozone is important to the overall climatology, budget and long-term trends of tropospheric ozone. Stratospheric intrusion events, however, are still poorly understood. Here we introduce the use of modern windprofiler radars to assist in such transport investigations. By hourly monitoring the radar-derived tropopause height in combination with a series of frequent ozonesonde balloon launches, we find numerous intrusions of ozone from the stratosphere into the troposphere in southeastern Canada. On some occasions, ozone is dispersed at altitudes of two to four kilometres, but on other occasions it reaches the ground, where it can dominate the ozone density variability. We observe rapid changes in radar tropopause height immediately preceding these intrusion events. Such changes therefore serve as a valuable diagnostic for the occurrence of ozone intrusion events. Our studies emphasize the impact that stratospheric ozone can have on tropospheric ozone, and show that windprofiler data can be used to infer the possibility of ozone intrusions, as well as better represent tropopause motions in association with stratosphere-troposphere transport.

  13. The impact of observing characteristics on the ability to predict ozone under varying polluted photochemical regimes

    NASA Astrophysics Data System (ADS)

    Hamer, P. D.; Bowman, K. W.; Henze, D. K.; Attié, J.-L.; Marécal, V.

    2015-09-01

    errors of lower than 5 ppbv (parts per billion by volume). Further, only observing intervals of 3 h or shorter were able to consistently achieve ozone prediction errors of 5 ppbv or lower across all photochemical regimes. Making observations closer to the prediction period and either in the morning or afternoon rush hour periods made greater improvements for ozone prediction: 0.2-0.3 ppbv for the morning rush hour and from 0.3 to 0.8 ppbv for the afternoon compared to only 0-0.1 ppbv for other times of the day. Finally, we made two complementary analyses that show that our conclusions are insensitive to the assumed diurnal emission cycle and to the choice of which VOC species emission to estimate using our framework. These questions will address how different types of observing platform, e.g. geostationary satellites or ground monitoring networks, could support future air quality research and forecasting.

  14. The Antarctic ozone hole

    NASA Technical Reports Server (NTRS)

    Molina, Mario J.

    1988-01-01

    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.

  15. [Characteristics of acid red 3R wastewater treatment by ozone microbubbles].

    PubMed

    Zhang, Jing; Du, Ya-Wei; Liu, Xiao-Jing; Zhou, Yu-Wen; Liu, Chun; Yang, Jing-Liang; Zhang, Lei

    2015-02-01

    The application of microbubble technology for ozonation wastewater treatment could enhance ozone mass transfer, improve ozonation performance and increase ozone utilization efficiency. The ozone microbubbles were used to treat synthetic acid red 3R wastewater in the present study, and compared to ozone conventional bubbles. The ozone mass transfer and ozonation characteristics of acid red 3R were investigated when ozone microbubbles and ozone conventional bubbles were applied. The results confirmed the enhanced ozone mass transfer using microbubbles. The ozone mass transfer coefficient using microbubbles was 3.6 times higher than that using conventional bubbles under the same conditions. Simultaneously, the ozone decomposition coefficient using microbubbles was 6.2 times higher than that using conventional bubbles, which would be favorable for *OH generation. The ozonation rate and mineralization efficiency of acid red 3R could be improved significantly using ozone microbubbles. A TOC removal efficiency of 78.0% was achieved using ozone microbubbles, which was about 2 times higher than that using ozone conventional bubbles. The ozone utilization efficiency using microbubbles was much higher that using conventional bubbles during ozonation treatment of acid red 3R. The average ozone utilization efficiencies were 97.8% and 69.3% when microbubbles and conventional bubbles were used, respectively. The oxidative ability of ozone microbubbles could be increased by enhancing *OH generation, and as a result, the oxidative reaction of degradation intermediates was accelerated by ozone microbubbles. Especially, the mineralization ability of small organic acid intermediates using ozone microbubbles was about 1.6 times higher than that using ozone conventional bubbles.

  16. Impacts of seasonal and regional variability in biogenic VOC emissions on surface ozone in the Pearl River Delta region, China

    SciTech Connect

    Situ, S.; Guenther, Alex B.; Wang, X. J.; Jiang, X.; Turnipseed, A.; Wu, Z.; Bai, J.; Wang, X.

    2013-12-05

    In this study, the BVOC emissions in November 2010 over the Pearl River Delta (PRD) region in southern China have been estimated by the latest version of a Biogenic Volatile Organic Compound (BVOC) emission model (MEGAN v2.1). The evaluation of MEGAN performance at a representative forest site within this region indicates MEGAN can estimate BVOC emissions reasonably well in this region except overestimating isoprene emission in autumn for reasons that are discussed in this manuscript. Along with the output from MEGAN, the Weather Research and Forecasting model with chemistry (WRF-Chem) is used to estimate the impacts of BVOC emissions on surface ozone in the PRD region. The results show BVOC emissions increase the daytime ozone peak by *3 ppb on average, and the max hourly impacts of BVOC emissions on the daytime ozone peak is 24.8 ppb. Surface ozone mixing ratios in the central area of Guangzhou- Foshan and the western Jiangmen are most sensitive to BVOC emissions BVOCs from outside and central PRD influence the central area of Guangzhou-Foshan and the western Jiangmen significantly while BVOCs from rural PRD mainly influence the western Jiangmen. The impacts of BVOC emissions on surface ozone differ in different PRD cities, and the impact varies in different seasons. Foshan and Jiangmen being most affected in autumn, result in 6.0 ppb and 5.5 ppb increases in surface ozone concentrations, while Guangzhou and Huizhou become more affected in summer. Three additional experiments concerning the sensitivity of surface ozone to MEGAN input variables show that surface ozone is more sensitive to landcover change, followed by emission factors and meteorology.

  17. Depletion of tropospheric ozone associated with mineral dust outbreaks.

    PubMed

    Soler, Ruben; Nicolás, J F; Caballero, S; Yubero, E; Crespo, J

    2016-10-01

    From May to September 2012, ozone reductions associated with 15 Saharan dust outbreaks which occurred between May to September 2012 have been evaluated. The campaign was performed at a mountain station located near the eastern coast of the Iberian Peninsula. The study has two main goals: firstly, to analyze the decreasing gradient of ozone concentration during the course of the Saharan episodes. These gradients vary from 0.2 to 0.6 ppb h(-1) with an average value of 0.39 ppb h(-1). The negative correlation between ozone and coarse particles occurs almost simultaneously. Moreover, although the concentration of coarse particles remained high throughout the episode, the time series shows the saturation of the ozone loss. The highest ozone depletion has been obtained during the last hours of the day, from 18:00 to 23:00 UTC. Outbreaks registered during this campaign have been more intense in this time slot. The second objective is to establish from which coarse particle concentration a significant ozone depletion can be observed and to quantify this reduction. In this regard, it has been confirmed that when the hourly particle concentration recorded during the Saharan dust outbreaks is above the hourly particle median values (N > N-median), the ozone concentration reduction obtained is statistically significant. An average ozone reduction of 5.5 % during Saharan events has been recorded. In certain cases, this percentage can reach values of higher than 15 %. PMID:27376369

  18. Ozone production in four major cities of China: sensitivity to ozone precursors and heterogeneous processes

    NASA Astrophysics Data System (ADS)

    Xue, L. K.; Wang, T.; Gao, J.; Ding, A. J.; Zhou, X. H.; Blake, D. R.; Wang, X. F.; Saunders, S. M.; Fan, S. J.; Zuo, H. C.; Zhang, Q. Z.; Wang, W. X.

    2013-10-01

    Despite a large volume of research over a number of years, our understandings of the key precursors that control tropospheric ozone production and the impacts of heterogeneous processes remain incomplete. In this study, we analyze measurements of ozone and its precursors made at rural/suburban sites downwind of four large Chinese cities - Beijing, Shanghai, Guangzhou and Lanzhou. At each site the same measurement techniques were utilized and a photochemical box model based on the Master Chemical Mechanism (v3.2) was applied, to minimize uncertainties in comparison of the results due to differences in methodology. All four cities suffered from severe ozone pollution. At the rural site of Beijing, export of the well-processed urban plumes contributed to the extremely high ozone levels (up to an hourly value of 286 ppbv), while the pollution observed at the suburban sites of Shanghai, Guangzhou and Lanzhou was characterized by intense in-situ ozone production. The major anthropogenic hydrocarbons were alkenes and aromatics in Beijing and Shanghai, aromatics in Guangzhou, and alkenes in Lanzhou. The ozone production was found to be in a VOCs-limited regime in both Shanghai and Guangzhou, and a mixed regime in Lanzhou. In Shanghai, the ozone formation was most sensitive to aromatics and alkenes, while in Guangzhou aromatics were the predominant ozone precursors. In Lanzhou, either controlling NOx or reducing emissions of olefins from the petrochemical industry would mitigate the local ozone production. The potential impacts of several heterogeneous processes on the ozone formation were assessed. The hydrolysis of dinitrogen pentoxide (N2O5), uptake of the hydroperoxyl radical (HO2) on particles, and surface reactions of NO2 forming nitrous acid (HONO) present considerable sources of uncertainty in the current studies of ozone chemistry. Further efforts are urgently required to better understand these processes and refine atmospheric models.

  19. Immunosuppression of pulmonary natural killer activity by exposure to ozone

    SciTech Connect

    Burleson, G.R.; Keyes, L.L.; Stutzman, J.D. )

    1989-01-01

    Ozone is an oxidant gas and an ubiquitous oxidant air pollutant with the potential to adversely affect pulmonary immune function with a consequent increase in disease susceptibility. Pulmonary natural killer (NK) activity was measured in order to assess the pulmonary immunotoxicity of continuous ozone exposure. Continuous ozone exposures at 1.0 ppm were performed for 23.5 hours per day for either 1, 5, 7, or 10 consecutive days. Pulmonary immune function was assessed by measuring natural killer (NK) activity from whole-lung homogenates of male Fischer-344 rats. Results of this study indicated that continuous ozone exposure for 1, 5, or 7 days resulted in a significant decrease in pulmonary NK activity. This suppressed pulmonary NK activity returned to control levels after continuous exposure to ozone for 10 days. The suppressed pulmonary NK response was thus attenuated and returned to normal values in the continued presence of ozone gas. This attenuation process is dynamic, complex, and doubtless involves several cell types and/or products of these cells. Pulmonary NK activity was also suppressed at 0.5 ppm ozone, but not at 0.1 ppm ozone, following 23.5 hours of exposure. NK activity is important for defense against viral, bacterial, and neoplastic disease. The depressed NK activity resulting from continuous ozone exposure could therefore result in a compromised ability to defend against pulmonary diseases.

  20. Meteorological Simulations of Ozone Episode Case Days during the 1996 Paso del Norte Ozone Study

    SciTech Connect

    Brown, M.J.; Costigan, K.; Muller, C.; Wang, G.

    1999-02-01

    Meteorological simulations centered around the border cities of El Paso and Ciudad Juarez have been performed during an ozone episode that occurred on Aug. 13,1996 during the 1996 Paso del Norte Ozone Study field campaign. Simulations were petiormed using the HOTMAC mesoscale meteorological model using a 1,2,4, and 8 km horizontal grid size nested mesh system. Investigation of the vertical structure and evolution of the atmospheric boundary layer for the Aug. 11-13 time period is emphasized in this paper. Comparison of model-produced wind speed profiles to rawirisonde and radar profiler measurements shows reasonable agreement. A persistent upper-level jet was captured in the model simulations through data assimilation. In the evening hours, the model was not able to produce the strong wind direction shear seen in the radar wind profiles. Based on virtual potential temperature profile comparisons, the model appears to correctly simulate the daytime growth of the convective mixed layer. However, the model underestimates the cooling of the surface layer at night. We found that the upper-level jet significantly impacted the turbulence structure of the boundary layer, leading to relatively high turbulent kinetic energy (tke) values aloft at night. The model indicates that these high tke values aloft enhance the mid-morning growth of the boundary layer. No upper-level turbulence measurements were available to verify this finding, however. Radar profiler-derived mixing heights do indicate relatively rapid morning growth of the mixed layer.

  1. PV Hourly Simulation Tool

    SciTech Connect

    Dean, Jesse; Metzger, Ian

    2010-12-31

    This software requires inputs of simple general building characteristics and usage information to calculate the energy and cost benefits of solar PV. This tool conducts and complex hourly simulation of solar PV based primarily on the area available on the rooftop. It uses a simplified efficiency calculation method and real panel characteristics. It includes a detailed rate structure to account for time-of-use rates, on-peak and off-peak pricing, and multiple rate seasons. This tool includes the option for advanced system design inputs if they are known. This tool calculates energy savings, demand reduction, cost savings, incentives and building life cycle costs including: simple payback, discounted payback, net-present value, and savings to investment ratio. In addition this tool also displays the environmental benefits of a project.

  2. PV Hourly Simulation Tool

    2010-12-31

    This software requires inputs of simple general building characteristics and usage information to calculate the energy and cost benefits of solar PV. This tool conducts and complex hourly simulation of solar PV based primarily on the area available on the rooftop. It uses a simplified efficiency calculation method and real panel characteristics. It includes a detailed rate structure to account for time-of-use rates, on-peak and off-peak pricing, and multiple rate seasons. This tool includes themore » option for advanced system design inputs if they are known. This tool calculates energy savings, demand reduction, cost savings, incentives and building life cycle costs including: simple payback, discounted payback, net-present value, and savings to investment ratio. In addition this tool also displays the environmental benefits of a project.« less

  3. Effect of inhaled ozone on lung histamine in conscious guinea pigs

    SciTech Connect

    Shields, R.L.; Gold, W.M.

    1987-04-01

    The effect of short-term ozone (O/sub 3/) exposure on pulmonary mast cell function was examined. Guinea pigs were continuously exposed to 1.0 ppm O/sub 3/ for 2, 4, and 8 hr. O/sub 3/ exposure produced a significant decrease in lung histamine concentration. Two-hour exposure to O/sub 3/ caused a 22.4 +/- 7.0% decrease in lung histamine concentration compared with controls. Ozone exposures of 4 and 8 hr caused lung histamine concentrations to decrease by 43.7 +/- 7.7 and 49.0 +/- 7.5%, respectively, without significant changes in lung water or protein, or evidence of cytotoxicity. These results suggest that O/sub 3/ or its metabolites affect pulmonary mast cell function by stimulating the release of histamine from the lung.

  4. A study on the effects of ozone dosage on dissolved-ozone flotation (DOF) process performance.

    PubMed

    Jin, Xin; Jin, Pengkang; Wang, Xiaochang

    2015-01-01

    Dissolved-ozone flotation (DOF) is a tertiary wastewater treatment process, which combines ozonation and flotation. In this paper, a pilot-scale DOF system fed by secondary effluent from a wastewater treatment plant (WWTP) in China was used to study the effect of ozone dosage on the DOF process performance. The results show that an ozone dosage could affect the DOF performance to a large extent in terms of color and organic matter removal as well as disinfection performance. The optimal color and organic matter removal was achieved at an ozone dosage of 0.8 mg/l. For disinfection, significant improvement in performance could be achieved only when the organic matter removal was optimal. The optimal ozone dosage of at least 1.6 mg/l was put forward, in this case, in order to achieve the optimal color, turbidity, organic matter and disinfection performance.

  5. Ozone interactions with human hair: Ozone uptake rates and product formation

    NASA Astrophysics Data System (ADS)

    Pandrangi, Lakshmi S.; Morrison, Glenn C.

    In this study, the cumulative ozone uptake, the ozone reaction probability and product yields of volatile aldehydes and ketones were quantified for human scalp hair. Hair was chosen because ozone reacts readily with skin oils and the personal-care products that coat hair. Due to their proximity to the breathing zone, these reactions can influence personal exposure to ozone and its volatile reaction products. Hair samples were collected before and after washing and/or application of personal hair-care products. Samples were exposed to ozone for 24 h in a tubular Teflon reactor; ozone consumption rates and product emission rates were quantified. The mean values of integrated ozone uptake, initial and final follicle reaction probability values for eight washed and unwashed samples were, respectively, 5.1±4.4 μmol O 3 g -1, (13±8)×10 -5, and (1.0±1.3)×10 -5. Unwashed hair taken close to the scalp exhibited the highest integrated ozone uptake and reaction probability, indicating that scalp oils are responsible for much of the ozone reactivity. Otherwise there was no significant difference between washed and unwashed hair. Compounds (geranyl acetone, 6-methyl-5-hepten-2-one, and decanal) associated with ozone reacting with sebum were observed as secondary products more frequently from unwashed hair than for washed hair and the summed yield of aldehydes ranged from 0.00 to 0.86. Based on reaction probabilities, cumulative ozone uptake and typical sebum generation rates, ozone flux to skin and hair is anticipated to be nearly transport limited, reducing personal exposure to ozone and increasing exposure to reaction products.

  6. Influence of the ozone profile above Madrid (Spain) on Brewer estimation of ozone air mass factor

    NASA Astrophysics Data System (ADS)

    Antón, M.; López, M.; Costa, M. J.; Serrano, A.; Bortoli, D.; Bañón, M.; Vilaplana, J. M.; Silva, A. M.

    2009-08-01

    The methodology used by Brewer spectroradiometers to estimate the ozone column is based on differential absorption spectroscopy. This methodology employs the ozone air mass factor (AMF) to derive the total ozone column from the slant path ozone amount. For the calculating the ozone AMF, the Brewer algorithm assumes that the ozone layer is located at a fixed height of 22 km. However, for a real specific site the ozone presents a certain profile, which varies spatially and temporally depending on the latitude, altitude and dynamical conditions of the atmosphere above the site of measurements. In this sense, this work address the reliability of the mentioned assumption and analyses the influence of the ozone profiles measured above Madrid (Spain) in the ozone AMF calculations. The approximated ozone AMF used by the Brewer algorithm is compared with simulations obtained using the libRadtran radiative transfer model code. The results show an excellent agreement between the simulated and the approximated AMF values for solar zenith angle lower than 75°. In addition, the relative differences remain lower than 2% at 85°. These good results are mainly due to the fact that the altitude of the ozone layer assumed constant by the Brewer algorithm for all latitudes notably can be considered representative of the real profile of ozone above Madrid (average value of 21.7±1.8 km). The operational ozone AMF calculations for Brewer instruments are limited, in general, to SZA below 80°. Extending the usable SZA range is especially relevant for Brewer instruments located at high mid-latitudes.

  7. [Ozone source apportionment at urban area during a typical photochemical pollution episode in the summer of 2013 in the Yangtze River Delta].

    PubMed

    Li, Hao; Li, Li; Huang, Cheng; An, Jing-yu; Yan, Ru-sha; Huang, Hai-ying; Wang, Yang-jun; Lu, Qing; Wang, Qian; Lou, Sheng-rong; Wang, Hong-li; Zhou, Min; Tao, Shi-kang; Qiao, Li-ping; Chen, Ming-hua

    2015-01-01

    With the fast development of urbanization, industrialization and mobilization, the air pollutant emissions with photochemical reactivity become more obvious, causing a severe photochemical pollution with the characteristics of high ozone concentration. However, the ozone source identification is very complicated due to the high non linearity between ozone and its precursors. Thus, ways to reduce ozone is still not clear. A high ozone pollution episode occurred during July, 2013, which lasted for a long period, with large influence area and high intensity. In this paper, we selected this episode to do a case study with the application of ozone source apportionment technology(OSAT) coupled within the CAMx air quality model. In this study, 4 source regions(including Shanghai, north Zhejiang, South Jiangsu and long range transport), 7 source categories (including power plants, industrial process, industrial boilers and kilns, residential, mobile source, volatile source and biogenic emissions) are analyzed to study their contributions to surface O3 in Shanghai, Suzhou and Zhejiang. Results indicate that long range transport contribution to the surface ozone in the YRD is around 20 x 10(-9) - 40 x 10(-9) (volume fraction). The O3 concentrations can increased to 40 x 10(-9) - 100 x 10(-9) (volume fraction) due to precursors emissions in Shanghai, Jiangsu and Zhejiang. As for the regional contribution to 8 hour ozone, long range transport constitutes 42.79% +/- 10.17%, 48.57% +/- 9.97% and 60.13% +/- 7.11% of the surface ozone in Shanghai, Suzhou and Hangzhou, respectively. Regarding the high O3 in Shanghai, local contribution is 28.94% +/- 8.49%, north Zhejiang constitutes 19.83% +/- 10.55%. As for surface O3 in Suzhou, the contribution from south Jiangsu is 26.41% +/- 6.80%. Regarding the surface O3 in Hangzhou, the major regional contributor is north Zhejiang (29.56% +/- 8.33%). Contributions from the long range transport to the daily maximum O3 concentrations are

  8. [Ozone source apportionment at urban area during a typical photochemical pollution episode in the summer of 2013 in the Yangtze River Delta].

    PubMed

    Li, Hao; Li, Li; Huang, Cheng; An, Jing-yu; Yan, Ru-sha; Huang, Hai-ying; Wang, Yang-jun; Lu, Qing; Wang, Qian; Lou, Sheng-rong; Wang, Hong-li; Zhou, Min; Tao, Shi-kang; Qiao, Li-ping; Chen, Ming-hua

    2015-01-01

    With the fast development of urbanization, industrialization and mobilization, the air pollutant emissions with photochemical reactivity become more obvious, causing a severe photochemical pollution with the characteristics of high ozone concentration. However, the ozone source identification is very complicated due to the high non linearity between ozone and its precursors. Thus, ways to reduce ozone is still not clear. A high ozone pollution episode occurred during July, 2013, which lasted for a long period, with large influence area and high intensity. In this paper, we selected this episode to do a case study with the application of ozone source apportionment technology(OSAT) coupled within the CAMx air quality model. In this study, 4 source regions(including Shanghai, north Zhejiang, South Jiangsu and long range transport), 7 source categories (including power plants, industrial process, industrial boilers and kilns, residential, mobile source, volatile source and biogenic emissions) are analyzed to study their contributions to surface O3 in Shanghai, Suzhou and Zhejiang. Results indicate that long range transport contribution to the surface ozone in the YRD is around 20 x 10(-9) - 40 x 10(-9) (volume fraction). The O3 concentrations can increased to 40 x 10(-9) - 100 x 10(-9) (volume fraction) due to precursors emissions in Shanghai, Jiangsu and Zhejiang. As for the regional contribution to 8 hour ozone, long range transport constitutes 42.79% +/- 10.17%, 48.57% +/- 9.97% and 60.13% +/- 7.11% of the surface ozone in Shanghai, Suzhou and Hangzhou, respectively. Regarding the high O3 in Shanghai, local contribution is 28.94% +/- 8.49%, north Zhejiang constitutes 19.83% +/- 10.55%. As for surface O3 in Suzhou, the contribution from south Jiangsu is 26.41% +/- 6.80%. Regarding the surface O3 in Hangzhou, the major regional contributor is north Zhejiang (29.56% +/- 8.33%). Contributions from the long range transport to the daily maximum O3 concentrations are

  9. Identifying and forecasting deep stratospheric ozone intrusions over the western United States from space

    NASA Astrophysics Data System (ADS)

    Lin, M.; Fiore, A. M.; Horowitz, L. W.; Cooper, O. R.; Langford, A. O.; Pan, L.; Liu, X.; Reddy, P. J.

    2012-12-01

    Recent studies have shown that deep stratospheric ozone intrusions can episodically enhance ground-level ozone above the health-based standard over the western U.S. in spring. Advanced warning of incoming intrusions could be used by state agencies to inform the public about poor air quality days. Here we explore the potential for using total ozone retrievals (version 5.2, level 3) at twice daily near global coverage from the AIRS instrument aboard the NASA Aqua satellite to identify stratospheric intrusions and forecast the eventual surface destination of transported stratospheric ozone. The method involves the correlation of AIRS daily total ozone columns at each 1ox1o grid box ~1-3 days prior to stratospheric enhancements to daily maximum 8-hour average ozone at a selected surface site using datasets from April to June in 2003-2011. The surface stratospheric enhancements are estimated by the GFDL AM3 chemistry-climate model which includes full stratospheric and tropospheric chemistry and is nudged to reanalysis winds. Our earlier work shows that the model presents deep stratospheric intrusions over the Western U.S. consistently with observations from AIRS, surface networks, daily ozone sondes, and aircraft lidar available in spring of 2010 during the NOAA CalNex field campaign. For the 15 surface sites in the U.S. Mountain West considered, a correlation coefficient of 0.4-0.7 emerges with AIRS ozone columns over 30o-50oN latitudes and 125o-105oW longitudes - variability in the AIRS column within this spatial domain indicates incoming intrusions. For each "surface receptor site", the spatial domain can narrow to an area ~5ox5o northwest of the individual site, with the strong correlation (0.5-0.7) occurring when the AIRS data is lagged by 1 day from the AM3 stratospheric enhancements in surface air. The spatial pattern of correlations is consistent with our process-oriented understanding developed from case studies of extreme intrusions. Surface observations

  10. New Total Ozone Algorithm for Application to the Total Ozone Mapping Spectrometer

    NASA Technical Reports Server (NTRS)

    Wellemeyer, C.; Bhartia, P. K.; Taylor, S. L.; Qin, W.; Flynn, L.; Seftor, C.

    2003-01-01

    The Total Ozone Mapping Spectrometer (TOMS) series comprises four instruments providing a total of 25 years of daily global stratospheric ozone data over the sunlit portion of the Earth. A new retrieval algorithm has been developed for TOMS, designated Version 8. The algorithm is based on differential absorption across a pair of wavelength channels chosen close together to minimize the impact of wavelength dependent forward modeling errors. Version 8 enhancements include correction for the presence of tropospheric aerosols and sun glint from water surfaces, a better treatment of variability due to tropospheric ozone and temperature dependence, and an improved forward model, particularly in regions of persistent snow and ice. Among other things, the Version 8 enhancements have reduced latitudinal dependence seen previously in TOMS - Dobson comparisons, predominantly in the Southern Hemisphere's summer, when the tropospheric ozone, temperature, and snow/ice corrections are additive. The basic components of the algorithm and its impact on derived total ozone will be discussed.

  11. Fixed Costs and Hours Constraints

    ERIC Educational Resources Information Center

    Johnson, William R.

    2011-01-01

    Hours constraints are typically identified by worker responses to questions asking whether they would prefer a job with more hours and more pay or fewer hours and less pay. Because jobs with different hours but the same rate of pay may be infeasible when there are fixed costs of employment or mandatory overtime premia, the constraint in those…

  12. Spatial patterns of tropospheric ozone in the Mount Rainier region of the Cascade Mountains, USA

    USGS Publications Warehouse

    Brace, S.; Peterson, D.L.

    1998-01-01

    Few data exist on tropospheric ozone concentrations in rural and wildland areas of western Washington, U.S.A. We measured tropospheric ozone in Mount Rainier National Park and the Puget Sound region of Washington using electronic analyzers and passive samplers during the summers of 1994 and 1995. Electronic analyzers recorded hourly ozone concentrations from five locations between Seattle and Mount Rainier. Ozone concentrations generally increased with distance from Seattle, with maximum hourly concentrations recorded at Enumclaw (319 m elevation, 50 km SE of Seattle). Paradise (1650 m elevation, 100 km SE of Seattle) had the highest monthly mean concentration of all sites measured with analyzers. Diurnal patterns on high-ozone days indicate that concentrations at Paradise remain near 60 ppbv throughout the day, whereas ozone concentrations closer to Seattle had higher peaks during the afternoon but dropped to near zero at night. Passive ozone samplers were used to measure weekly average ozone exposures in four river drainages within Mount Rainier National Park, across an elevation gradient (420 a??2100 m). In most drainages, ozone levels increased with elevation, with highest average weekly ozone exposure (47 ppbv) recorded at 2100 m. Ozone concentrations are significantly higher in the western portion of the park, indicating that ozone exposure varies considerably over short distances. These data provide a reference point for air quality in western Washington and indicate that intensive sampling is necessary to quantify spatial patterns of tropospheric ozone in mountainous regions.

  13. 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.

  14. Ozone Gardens for the Citizen Scientist

    NASA Technical Reports Server (NTRS)

    Pippin, Margaret; Reilly, Gay; Rodjom, Abbey; Malick, Emily

    2016-01-01

    NASA Langley partnered with the Virginia Living Museum and two schools to create ozone bio-indicator gardens for citizen scientists of all ages. The garden at the Marshall Learning Center is part of a community vegetable garden designed to teach young children where food comes from and pollution in their area, since most of the children have asthma. The Mt. Carmel garden is located at a K-8 school. Different ozone sensitive and ozone tolerant species are growing and being monitored for leaf injury. In addition, CairClip ozone monitors were placed in the gardens and data are compared to ozone levels at the NASA Langley Chemistry and Physics Atmospheric Boundary Layer Experiment (CAPABLE) site in Hampton, VA. Leaf observations and plant measurements are made two to three times a week throughout the growing season.

  15. Variational data assimilation for the optimized ozone initial state and the short-time forecasting

    NASA Astrophysics Data System (ADS)

    Park, Soon-Young; Kim, Dong-Hyeok; Lee, Soon-Hwan; Lee, Hwa Woon

    2016-04-01

    In this study, we apply the four-dimensional variational (4D-Var) data assimilation to optimize initial ozone state and to improve the predictability of air quality. The numerical modeling systems used for simulations of atmospheric condition and chemical formation are the Weather Research and Forecasting (WRF) model and the Community Multiscale Air Quality (CMAQ) model . The study area covers the capital region of South Korea, where the surface measurement sites are relatively evenly distributed. The 4D-Var code previously developed for the CMAQ model is modified to consider background error in matrix form, and various numerical tests are conducted. The results are evaluated with an idealized covariance function for the appropriateness of the modified codes. The background error is then constructed using the NMC method with long-term modeling results, and the characteristics of the spatial correlation scale related to local circulation is analyzed. The background error is applied in the 4D-Var research, and a surface observational assimilation is conducted to optimize the initial concentration of ozone. The statistical results for the 12-hour assimilation periods and the 120 observatory sites show a 49.4% decrease in the root mean squred error (RMSE), and a 59.9% increase in the index of agreement (IOA). The temporal variation of spatial distribution of the analysis increments indicates that the optimized initial state of ozone concentration is transported to inland areas by the clockwise-rotating local circulation during the assimilation windows. To investigate the predictability of ozone concentration after the assimilation window, a short-time forecasting is carried out. The ratios of the RMSE with assimilation versus that without assimilation are 8% and 13% for the +24 and +12 hours, respectively. Such a significant improvement in the forecast accuracy is obtained solely by using the optimized initial state. The potential improvement in ozone prediction for

  16. Evaluating 2012 Ozone Impacts of Natural Gas Development in the Haynesville Shale with an Updated Emission Inventory

    NASA Astrophysics Data System (ADS)

    Kemball-Cook, S. R.; Bar-Ilan, A.; Yarwood, G.

    2013-12-01

    The Haynesville Shale, located approximately 10,000-13,000 feet beneath Northeast Texas and Northwest Louisiana contains very large recoverable reserves of natural gas. Development of the Haynesville began in 2008, and since then, more than 3,000 wells have been drilled. The development of natural gas resources in the Haynesville is economically important, but also generates emissions of ozone precursors in a region with several ozone monitors that are close to or exceeding the 2008 National Ambient Air Quality Standard. During 2009, we developed an emission inventory of ozone precursors for projected future Haynesville Shale development from 2009 through 2020. Photochemical modeling with the 2012 emission inventory showed significant ozone impacts within Northeast Texas and Northwest Louisiana as a result of Haynesville emissions, with projected 8-hour ozone design value increases up to 5 ppb at area monitors. The original emission inventory was assembled during spring 2009, early in the development of the Haynesville when available data were limited. Since then, development in the Haynesville has continued, and additional data are now available and were used to refine the development projections and emission inventory through the year 2020. The updated 2012 emission inventory is now based on actual data rather than projections made in 2009. The number of drilling rigs operating in 2012 was lower than projected, but the well count was higher due intensive drilling activity in 2010-2011 that exceeded projections. The updated emission inventory draws on more Haynesville-specific data than the previous inventory. Energy producers currently active in the Haynesville were surveyed and provided information that included well drilling times, equipment used for well construction, production equipment present at typical Haynesville wells, and produced gas composition analyses. Producers provided information on the amount of truck traffic associated with transport of

  17. Characteristics of ozone and ozone precursors (VOCs and NOx) around a petroleum refinery in Beijing, China.

    PubMed

    Wei, Wei; Cheng, Shuiyuan; Li, Guohao; Wang, Gang; Wang, Haiyang

    2014-02-01

    A field measurement campaign for ozone and ozone precursors (VOCs and NOx) was conducted in summer 2011 around a petroleum refinery in the Beijing rural region. Three observation sites were arranged, one at southwest of the refinery as the background, and two at northeast of the refinery as the downwind receptors. Monitoring data revealed the presence of serious surface O3 pollution with the characteristics of high average daily mean and maximum concentrations (64.0 and 145.4 ppbV in no-rain days, respectively) and multi-peak diurnal variation. For NOx, the average hourly concentrations of NO2 and NO were in the range of 20.5-46.1 and 1.8-6.4 ppbV, respectively. For VOC measurement, a total of 51 compounds were detected. Normally, TVOCs at the background site was only dozens of ppbC, while TVOCs at the downwind sites reached several hundreds of ppbC. By subtracting the VOC concentrations at background, chemical profiles of VOC emission from the refinery were obtained, mainly including alkanes (60.0% +/- 4.3%), alkenes (21.1% +/- 5.5%) and aromatics (18.9% +/- 3.9%). Moreover, some differences in chemical profiles for the same measurement hours were observed between the downwind sites; the volume ratios of alkanes with low reactivity and those of alkenes with high reactivity respectively showed an increasing trend and a decreasing trend. Finally, based on temporal and spatial variations of VOC mixing ratios, their photochemical degradations and dispersion degradations were estimated to be 0.15-0.27 and 0.42-0.62, respectively, by the photochemical age calculation method, indicating stronger photochemical reactions around the refinery.

  18. Nonstationary effects in ozone generation by barrier discharges in N2/O2 mixtures

    NASA Astrophysics Data System (ADS)

    Zosimov, A. V.; Lunin, V. V.; Samoilovich, V. G.; Abramovskaya, E. A.; Mankelevich, Yu. A.; Poroykov, A. Yu.; Rakhimova, T. V.; Voloshin, D. G.

    2016-08-01

    The yield of ozone in barrier discharges in oxygen-nitrogen mixtures containing 0.001 to 40% of nitrogen is investigated experimentally. Phenomena of the nonstationarity of processes of ozone generation that differ from the known ozone-zero phenomenon (OZP) apparent in the reduced efficiency of ozone generation in very high purity oxygen at long periods (from hours to tens of hours) of ozonator operation are found. It is established that the characteristic times (from minutes to tens of minutes) of ozone attaining stationary values after changes in the discharge parameters indicate slow adjustment of the surface condition of insulators and thus the heterogeneous decay of ozone to more rapidly changing flows of neutral and charged particles from gas discharge plasma on the surfaces of dielectrics. The possibility of such a scenario is confirmed using a new analytical approach and numerical calculations of the plasma-chemical kinetics of N2/O2 mixtures presented in the accompanying theoretical study.

  19. The interpretation of SAGE II ozone measurements in the lower mesosphere

    SciTech Connect

    Chu, D.C.A.

    1989-01-01

    SAGE II observations of ozone at sunrise and sunset (solar zenith angle=90{degree}) at approximately the same tropical latitude and on the same day exhibit larger concentrations at sunrise than at sunset between 55 km and 65 km altitude. Because of rapid conversion of atomic oxygen to ozone at sunset and the reverse at sunrise, the onion peeling assumption of constant ozone in the SAGE II retrievals is invalid in this altitude range. The observations are compared against predictions from a one-dimensional model by deriving simulated ozone profiles obtained by applying the onion peel procedure to model results. Good agreement between the observed and modeled sunrise/sunset ratios is then obtained. The results indicate that the SAGE II ozone retrievals overestimate by a factor of 1.3 at sunrise and 1.1 at sunset at 65 km (for example). Between 55 and 60 km altitude the Chapman reactions produce an adequate simulation of the sunrise and sunset ratio, but between 60 and 65 km this ratio is affected by the destruction of O{sub x} by HO{sub x} during the first part of the night. SAGE II ozone profiles between 60 and 65 km altitude thus provide information on mesospheric HO{sub x} chemistry not only through profiles averages but also through the sunrise/sunset ratio. The observations, for example, indicate an OH concentration at 65 km altitude in the tropics an hour after dark of approximately 8x10{sup 6} cm{sup {minus}3}.

  20. Ozone depletion at northern and southern latitudes derived from January 1979 to December 1991 Total Ozone Mapping Spectrometer Data

    SciTech Connect

    Herman, J.R.; McPeters, R.; Larko, D.

    1993-07-20

    Long-term ozone depletion rates (percentage change) have been computed from 13 years of Nimbus 8/Total Ozone Mapping Spectrometer (TOMS) data as a function of latitude, longitude, and month for the period January 1, 1979, to December 31, 1991. In both hemispheres the amount of ozone has decreased at latitudes above 30{degrees} by amounts that are larger than predicted by homogeneous chemistry models for the 13-year time period. The largest rates of ozone decrease occur in the southern hemisphere during winter and spring, with partial recovery during the summer and autumn. Outside of the Antarctic ozone hole region, the 12-year ozone depletion rates reach 8-10% per decade during the winter and spring at 55{degrees}S. Ozone depletion rates in excess of 7% per decade occur over populated regions in the southern hemisphere poleward of 45{degrees}S for 7 months of the year. Similar rates of decrease occur during northern winter and spring over large populated regions. The enhanced zonal average ozone depletion rates at northern mid-latitudes (40-50{degrees}N) during January, February, and March, that correspond to five geographically localized regions of high ozone depletion rates, are probably associated with long-term dynamical or temperature changes. Only the equatorial band between {+-}20{degrees} shows little or no long-term ozone change since January 1979. Ozone time series data have been examined for effect of volcanic eruptions on stratospheric ozone observed by TOMS, with only the Mount Pinatubo stratospheric aerosol injection affecting ozone amounts for a few months after the eruption in June 1991. Errors caused by the short-term presence of stratospheric aerosols in the TOMS zonally averaged ozone data are less than 1% before correction, and have no significant effect on ozone trend determination. 49 refs., 6 figs., 2 tabs.

  1. Indoor ozone concentrations: Ventilation rate impacts and mechanisms of outdoor concentration attenuation

    SciTech Connect

    Cano-Ruiz, J.A.; Modera, M.P.; Nazaroff, W.W.

    1992-07-01

    The classification of outdoor (ambient) air as fresh for the purposes of ventilation is not always appropriate, particularly in urban areas. In many cities of the world, urban air frequently violates health-based air quality standards due to high ozone concentrations. The degree of protection from exposure to ozone offered by the indoor environment depends on the relationship between indoor and outdoor ozone levels. Existing concentration data indicates that indoor/outdoor ozone ratios range between 10 and 80%. This paper analyzes several of the key issues influencing indoor ozone concentrations, including: (1) the degree of penetration of outdoor ozone indoors, (2) removal within the indoor environment (removal at surfaces and within air distribution systems), and (3) the correlation in time between outdoor ozone levels and ventilation rates. A model for calculating the degree of ozone removal in typical building leaks and air distribution systems is described and applied to a range of typical cases. This model indicates that the degree of removal is minimal for most wooden building cracks, but could be significant in leaks in concrete or brick structures, and is strongly dependent on the lining material for air distribution systems. Indoor ozone exposure estimates based on hourly outdoor ozone monitoring data and hour-by-hour weather-based simulations of infiltration rates and building operation are reported for a few residential scenarios. These estimates serve as a basis for exploring the impact of energy-efficient ventilation strategies on indoor ozone exposures.

  2. 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.

  3. 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.

  4. The role of refinery flaring events and bay breezes on a high surface ozone episode during the Houston, Texas DISCOVER-AQ field campaign

    NASA Astrophysics Data System (ADS)

    Loughner, C.; Follette-Cook, M. B.; Fried, A.; Pickering, K. E.

    2015-12-01

    The highest observed surface ozone concentrations in the Houston metropolitan area in 2013 occurred on September 25, which coincided with the Texas DISCOVER-AQ (Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality) field campaign. Surface ozone was elevated throughout the Houston metropolitan area with maximum 8-hour average ozone peaking along the western shore of Galveston Bay, reaching 124 ppbv, almost 50 ppbv above the current EPA standard of 75 ppbv. The NASA P-3B aircraft observed plumes from refinery flares west and northwest of Galveston Bay that were transported over the water. Continental air pollution from the north was transported into the Houston metropolitan area where it mixed with locally generated emissions. A bay breeze circulation formed causing pollutants that were transported out over the water in the morning to recirculate back inland where they mixed with freshly emitted pollution near the bay breeze convergence zone. The highest surface ozone concentrations were reported near the bay breeze front. This ozone episode will be presented using measurements made during the DISCOVER-AQ field campaign and a CMAQ model simulation with integrated source apportionment, which tracks the contribution of emissions source groups and regions on ozone concentrations.

  5. Ozone levels in passenger cabins of commercial aircraft on North American and transoceanic routes.

    PubMed

    Bhangar, Seema; Cowlin, Shannon C; Singer, Brett C; Sextro, Richard G; Nazaroff, William W

    2008-06-01

    Ozone levels in airplane cabins, and factors that influence them, were studied on northern hemisphere commercial passenger flights on domestic U.S., transatlantic, and transpacific routes. Real-time data from 76 flights were collected in 2006--2007 with a battery-powered UV photometric monitor. Sample mean ozone level, peak-hour ozone level, and flight-integrated ozone exposures were highly variable across domestic segments (N = 68), with ranges of < 1.5 to 146 parts per billion by volume (ppbv), 3--275 ppbv, and < 1.5 to 488 ppbv-hour, respectively. On planes equipped with ozone catalysts, the mean peak-hour ozone level (4.7 ppbv, N = 22)was substantially lower than on planes not equipped with catalysts (47 ppbv, N = 46). Peak-hour ozone levels on eight transoceanic flight segments, all on planes equipped with ozone catalysts, were in the range < 1.5 to 65 [corrected] ppbv. Seasonal variation on domestic routes without converters is reasonably modeled by a sinusoidal curve that predicts peak-hour levels to be approximately 70 ppbv higher in Feb--March than in Aug--Sept The temporal trend is broadly consistent with expectations, given the seasonal cycle in tropopause height. Episodically elevated (>100 ppbv) ozone levels on domestic flights were associated with winter-spring storms that are linked to enhanced exchange between the lower stratosphere and the upper troposphere.

  6. 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...

  7. 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.).

  8. A passive ozone sampler based on a reaction with iodide.

    PubMed

    Yanagisawa, Y

    1994-02-01

    A new passive sampler for ozone and its simple analytical system have been developed. Because it is small and sensitive, the sampler can be used for determining personal exposures to ozone and oxidants and for multilocation measurements. The sampler consists of an electrode, a spacer, and several layers of membrane filters and Teflon meshes. The electrode is a carbon paper disk coated with nylon-6 polymer and potassium iodide. The membrane filters are used to remove interferences. A sampling rate of ozone is controlled by the spacer and Teflon meshes. Iodine is liberated by an oxidation reaction of potassium iodide with ozone. The iodine is stabilized by forming a charge transfer complex with nylon-6 and is accumulated in the nylon-6 layer. The amount of iodine, which is proportional to the level of ozone exposure, is quantified by constant current coulometry. The discharge time of a galvanic battery is measured using the electrode as a positive electrode and a zinc plate as a counter electrode. A time-weighted average concentration of ozone is derived from the discharge time after exposing the electrode to ozone. The effects of various environmental conditions on the sampler's performance were investigated. The results indicated that the sampler showed a linear response to ozone exposure up to 1,450 parts per billion for every hour of use (ppb.hour). The minimum detectable exposure was about 400 ppb.hour. The effects of surface wind velocity, temperature, and humidity were small. However, a relative humidity below 20% resulted in an underestimation of the ozone concentration. Because the electrode requires no pretreatment and the analytical method is very simple, this method is suitable for large-scale studies of personal exposures to ozone and oxidants using multilocation measurements.

  9. Tunable Diode Laser Heterodyne Spectrophotometry of Ozone

    NASA Technical Reports Server (NTRS)

    Fogal, P. F.; McElroy, C. T.; Goldman, A.; Murcray, D. G.

    1988-01-01

    Tunable diode laser heterodyne spectrophotometry (TDLHS) has been used to make extremely high resolution (less than 0.0005/ cm) solar spectra in the 9.6 micron ozone band. Observations have shown that a signal-to-noise ratio of 95 : 1 (35% of theoretical) for an integration time of 1/8 second can be achieved at a resolution of 0.0005 wavenumbers. The spectral data have been inverted to yield a total column amount of ozone, in good agreement with that. measured at the nearby National Oceanographic and Atmospheric Administration (NOAA) ozone monitoring facility in Boulder, Colorado.

  10. Evaluation of the production and the destruction of ozone in the lower atmosphere

    NASA Technical Reports Server (NTRS)

    Muramatsu, H.

    1994-01-01

    Observed surface ozone mixing ratio X(sub ob) is partitioned into two parts; X(sub tr), transported from the free troposphere and X(sub ch), chemically produced or destructed in the boundary layer. X(sub tr) is estimated from the ozone concentration in the free troposphere and the wind speed. The ozone in the free troposphere estimated from surface ozone observations is consistent with that of ozonesonde data. X(sub ch) is obtained from the difference between X(sub ob) and X(sub tr). X(sub tr) increases with wind speed, while X(sub ch) shows maximum at hourly wind speed of 1-2 m/s in the daytime. Contribution of X(sub tr) to X(sub ob) is larger than X(sub ch) except for a short period in summer. X(sub ch) is positive for April-October, but X(sub ch) can be negative in winter, showing the net chemical destruction in the boundary layer. X(sub ch) increases linearly with solar radiation, and is negative for daily global solar radiation below 8 MJ/sq m, which is about equal to the monthly mean in winter.

  11. Application of ozone for reduction of mycological infection in wheat grain.

    PubMed

    Raila, Algirdas; Lugauskas, Albinas; Steponavicius, Dainius; Railiene, Marija; Steponaviciene, Ausra; Zvicevicius, Egidijus

    2006-01-01

    In 2004-2005 means were sought to clean grain from microbiological contamination during transportation and storage. For this purpose, grains with a moisture content of 23.2 % of the "Tauras" variety were selected and ventilated daily for 8 hours until grain wetness was reduced to 14.0 %. The effect of ventilation duration and ozone impact was evaluated according to the changes in grain contamination with micromycetes propagules (cfu x g (-1)), and alternation of micromycetes species on the grain surface. At drying grains by active ventilation with an ozone--air mixture, at O (3) concentration of 700 ppb, the drying period was reduced by about 20 %, and mycological contamination depends on initial grain moisture content (w): when w=15.2 %, contamination was reduced by up to 2.2 times, and when w=22.0 %--up to 3 times. At the same time, the composition of micromycetes species on the grain surface changed significantly: in non-ventilated grain there were detected micromycetes of 26 species, and in ventilated grain--of 11 species. Efficient ozone impact was established only when the mound of wet (w>18.0 %) grains was exposed to ozone.

  12. Quantifying Ozone Production throughout the Boundary Layer from High Frequency Tethered Profile Measurements during a High Ozone Episode in the Uinta Basin, Utah

    NASA Astrophysics Data System (ADS)

    Sterling, C. W.; Johnson, B.; Schnell, R. C.; Oltmans, S. J.; Cullis, P.; Hall, E. G.; Jordan, A. F.; Windell, J.; McClure-Begley, A.; Helmig, D.; Petron, G.

    2015-12-01

    During the Uinta Basin Winter Ozone Study (UBWOS) in Jan - Feb 2013, 735 tethered ozonesonde profiles were obtained at 3 sites including during high wintertime photochemical ozone production events that regularly exceeded 125 ppb. High resolution profiles of ozone and temperature with altitude, measured during daylight hours, showed the development of approximately week long high ozone episodes building from background levels of ~40 ppb to >150 ppb. The topography of the basin combined with a strong temperature inversion trapped oil and gas production effluents in the basin and the snow covered surface amplified the sun's radiation driving the photochemical ozone production at rates up to 13 ppb/hour in a cold layer capped at 1600-1700 meters above sea level. Beginning in mid-morning, ozone mixing ratios throughout the cold layer increased until late afternoon. Ozone mixing ratios were generally constant with height indicating that ozone production was nearly uniform throughout the depth of the cold pool. Although there was strong diurnal variation, ozone mixing ratios increased during the day more than decreased during the night, resulting in elevated levels the next morning; an indication that nighttime loss processes did not compensate for daytime production. Even though the 3 tethersonde sites were at elevations differing by as much as 140 m, the top of the high ozone layer was nearly uniform in altitude at the 3 locations. Mobile van surface ozone measurements across the basin confirmed this capped structure of the ozone layer; the vehicle drove out of high ozone mixing ratios at an elevation of ~1900 meters above sea level, above which free tropospheric ozone mixing ratios of ~50 ppb were measured. Exhaust plumes from a coal-fired power plant in the eastern portion of the basin were intercepted by the tethersondes. The structure of the profiles clearly showed that effluents in the plumes were not mixed downward and thus did not contribute precursor nitrogen

  13. Decadal evolution of the Antarctic ozone hole

    NASA Technical Reports Server (NTRS)

    Jiang, Y.; Yung, Y. L.; Zurek, R. W.

    1996-01-01

    Ozone column amounts obtained by the total ozone mapping spectrometer (TOMS) in the southern polar region are analyzed 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 (1 PVU = 1.0 x 10(-6) K kg-1 m2 s-1) contour on the 500 K isentropic surface. The principal results are: (1) 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, and (2) the vortex-averaged column ozone in late August (day 240) has dropped by 70 Dobson units (DU) in a decade due to the loss in the dark and the dilution effect. The mean ozone depletion rate in the vortex between day 240 and the day of minimum vortex-averaged ozone is about 1 DU d-1 at the beginning of the decade, increasing to about 1.8 DU d-1 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-1 (3.8%) from 1980 to 1987 (90 DU over 8 years) and at a smaller rate of 2 DU yr-1 (0.9%) from 1987 to 1991 (10 DU over 5 years, excluding the anomalous year 1988). We interpret the year-to-year trend in the ozone depletion rate during the earlier part of the decade as due to the rise of anthropogenic chlorine in the atmosphere. The slower trend at the end of the decade indicates saturation of ozone depletion in the vortex interior, in that chlorine amounts in the mid-1980s were already sufficiently high to deplete most of the ozone in air within the isolated regions of the lower-stratospheric polar vortex. In subsequent years, increases in stratospheric chlorine may have enhanced wintertime chemical loss of ozone in the south polar vortex even before major losses during the Antarctic spring.

  14. 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.

  15. Remedial Process Optimization and Green In-Situ Ozone Sparging for Treatment of Groundwater Impacted with Petroleum Hydrocarbons

    NASA Astrophysics Data System (ADS)

    Leu, J.

    2012-12-01

    A former natural gas processing station is impacted with TPH and BTEX in groundwater. Air sparging and soil vapor extraction (AS/AVE) remediation systems had previously been operated at the site. Currently, a groundwater extraction and treatment system is operated to remove the chemicals of concern (COC) and contain the groundwater plume from migrating offsite. A remedial process optimization (RPO) was conducted to evaluate the effectiveness of historic and current remedial activities and recommend an approach to optimize the remedial activities. The RPO concluded that both the AS/SVE system and the groundwater extraction system have reached the practical limits of COC mass removal and COC concentration reduction. The RPO recommended an in-situ chemical oxidation (ISCO) study to evaluate the best ISCO oxidant and approach. An ISCO bench test was conducted to evaluate COC removal efficiency and secondary impacts to recommend an application dosage. Ozone was selected among four oxidants based on implementability, effectiveness, safety, and media impacts. The bench test concluded that ozone demand was 8 to 12 mg ozone/mg TPH and secondary groundwater by-products of ISCO include hexavalent chromium and bromate. The pH also increased moderately during ozone sparging and the TDS increased by approximately 20% after 48 hours of ozone treatment. Prior to the ISCO pilot study, a capture zone analysis (CZA) was conducted to ensure containment of the injected oxidant within the existing groundwater extraction system. The CZA was conducted through a groundwater flow modeling using MODFLOW. The model indicated that 85%, 90%, and 95% of an injected oxidant could be captured when a well pair is injecting and extracting at 2, 5, and 10 gallons per minute, respectively. An ISCO pilot test using ozone was conducted to evaluate operation parameters for ozone delivery. The ozone sparging system consisted of an ozone generator capable of delivering 6 lbs/day ozone through two ozone

  16. 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.

  17. 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.

  18. Record High Free Tropospheric Ozone in the Spring of 2015 over the Western US and its Influence of Surface Air Quality

    NASA Astrophysics Data System (ADS)

    Jaffe, D. A.; Baylon, P.

    2015-12-01

    In the Western US (WUS) background ozone is a significant fraction of the health and regulatory thresholds. Several researchers have previously shown that background free tropospheric O3 can significantly impact surface sites, including urban areas in the WUS (e.g. Jaffe 2011; Langford et al 2012; Lin et al 2012; Wigder et al 2013). The Mt Bachelor Observatory (MBO) has measured ozone in the free troposphere since 2004. Between 2004-2014, the median springtime ozone mixing ratio was found to be 44 ppbv, with a positive trend of 0.7 ppbv per year (Gratz et al 2014). Superimposed on this trend are daily and inter-annual variations. Up until 2014, the spring of 2012 had the highest median ozone mixing ratio at MBO (48 ppbv) and this had significant influence on many surface sites across the WUS including, for example, Boise ID, Salt Lake City UT and Reno NV. Each of these sites demonstrated an unusual number of days in spring 2012 with an 8-hour maximum ozone mixing ratios greater than 70 ppbv. In 2012, this influence reflected an enhanced flux from the upper troposphere/lower stratosphere to the lower free troposphere and ultimately the surface. In spring of 2015, we recorded our highest median ozone mixing ratio ever observed at MBO (56 ppbv). In contrast to 2012, enhanced ozone in the spring 2015 was associated with transport of emissions from Siberian wildfires. We expect that surface ozone at urban sites in the WUS will be significantly enhanced in the spring of 2015, as we saw in 2012. The combined influence of increasing baseline ozone and interannual variations on top of this rising baseline means that surface ozone in the WUS will continue to be an increasing challenge for air quality managers. While observations at MBO are extremely useful in this regard, we propose that additional observations of baseline ozone would prove useful to better understand the influence of background ozone on urban air quality in the WUS.

  19. Lower tropospheric ozone and aerosol measurements at a coastal mountain site in Central California

    NASA Astrophysics Data System (ADS)

    Post, A.; Faloona, I. C.; Lighthall, D.; Wexler, A. S.; Cliff, S. S.; Conley, S. A.; Zhao, Y.

    2013-12-01

    Increasing concern over the impacts of exogenous air pollution in California's Central Valley has prompted the establishment of a coastal, high altitude monitoring site at the Chews Ridge Observatory (1550 m) approximately 30 km east of Point Sur in Monterey County, operated by the Monterey Institute for Research in Astronomy. Eighteen months of ozone and aerosol measurements are presented in the context of long-range transport and its potential impact on surface air quality in the southern San Joaquin Valley. Moreover, several ozone surveys have been conducted by aircraft upwind, over the Pacific Ocean, and downwind, over the Central Valley, to characterize horizontal and vertical transport across the coastal mountains. Diurnal variations present at Chews Ridge indicate the formation of a convective boundary layer on the ridge during the daytime leading to a 6-8 ppb decrease in ozone accompanied by a rise in specific humidity of 2-3 g/kg due to coupling with the forest. During the nighttime, the sampled air masses are representative of free tropospheric conditions which have not been significantly influenced by either local emissions nor convective coupling to the surface. The maximum daily 8-hour average ozone concentration at Chews Ridge is used in lagged correlation analysis with two sites in the San Joaquin Valley, Fresno and Arvin, to de-emphasize the influence of locally produced, diurnally cycled ozone. The correlation coefficients (~0.60) peak between 9-21 hour lag and tend to decorrelate completely within 4-5 days. These and other analyses along with data provided by the aircraft sampling are used to provide a deeper understanding of ozone transport into the San Joaquin Valley. Aerosol size is measured with a scanning mobility particle sizer and composition is analyzed with an 8-stage rotating drum impactor whose substrates are characterized by X-ray fluorescence. Various elemental ratios and back trajectory calculations are used to infer the temporal

  20. Meteor 3/total ozone mapping spectrometer observations of the 1993 ozone hole

    NASA Technical Reports Server (NTRS)

    Herman, J. R.; Newman, P. A.; Mcpeters, R.; Krueger, A. J.; Bhartia, P. K.; Seftor, C. J.; Torres, O.; Jaross, G.; Cebula, R. P.; Larko, D.

    1995-01-01

    The development of the springtime (September-November) Antarctic ozone hole was observed by the Meteor 3/total ozone mapping spectromter (TOMS) to result in the lowest ozone value, 85 DU (Dobson units) on October 8, 1993, ever measured by TOMS. During late September and early October the region of extremely low ozone values was centered on the geographical pole between 85 deg S and 90 deg S. The geographical extent of the ozone hole region, the area within the 220-DU contour, reached a maximum during the first week in October at a near-circular area covering 24 x 10(exp 6) sq km reaching to the southern tip of South America. This approximately matched the 1992 area record. After the maximum area was reached in early October, the 1993 ozone hole region was significantly larger than during 1992 throughout the remainder of the month of October. The very low ozone values over the Antarctic continent have been confirmed by independent ground-based data. Unlike 1992, the formation of the 1993 Antarctic ozone hole does not coincide with unusually low ozone values observed over most of the globe for the past 2 years. The most recent ozone data from Meteor 3/TOMS show that there has been a recovery at all latitudes from the extraordinarily low values observed during 1992 and part of 1993 after the June 1991 eruption of Mount Pinatubo. Meteor 3/TOMS is described and compared with Nimbus 7/TOMS during the 1991 to May 1993 overlap period. Observations of the 1992 ozone hole are presented from both instruments and are shown to agree within 5 DU.

  1. Meteor 3/total ozone mapping spectrometer observations of the 1993 ozone hole

    SciTech Connect

    Herman, J.R.; Newman, P.A.; Mcpeters, R.; Krueger, A.J.; Bhartia, P.K.; Seftor, C.J.; Torres, O.; Jaross, G.; Cebula, R.P.; Larko, D. |

    1995-02-01

    The development of the springtime (September-November) Antarctic ozone hole was observed by the Meteor 3/total ozone mapping spectromter (TOMS) to result in the lowest ozone value, 85 DU (Dobson units) on October 8, 1993, ever measured by TOMS. During late September and early October the region of extremely low ozone values was centered on the geographical pole between 85 deg S and 90 deg S. The geographical extent of the ozone hole region, the area within the 220-DU contour, reached a maximum during the first week in October at a near-circular area covering 24 x 10(exp 6) sq km reaching to the southern tip of South America. This approximately matched the 1992 area record. After the maximum area was reached in early October, the 1993 ozone hole region was significantly larger than during 1992 throughout the remainder of the month of October. The very low ozone values over the Antarctic continent have been confirmed by independent ground-based data. Unlike 1992, the formation of the 1993 Antarctic ozone hole does not coincide with unusually low ozone values observed over most of the globe for the past 2 years. The most recent ozone data from Meteor 3/TOMS show that there has been a recovery at all latitudes from the extraordinarily low values observed during 1992 and part of 1993 after the June 1991 eruption of Mount Pinatubo. Meteor 3/TOMS is described and compared with Nimbus 7/TOMS during the 1991 to May 1993 overlap period. Observations of the 1992 ozone hole are presented from both instruments and are shown to agree within 5 DU.

  2. Direct ozone production rate measurements and their use in assessing ozone source and receptor regions for Houston in 2013

    NASA Astrophysics Data System (ADS)

    Baier, Bianca C.; Brune, William H.; Lefer, Barry L.; Miller, David O.; Martins, Douglas K.

    2015-08-01

    Mitigating ozone pollution involves reducing ozone production and relies on complex air-quality models to design reduction strategies and determine their effectiveness. However, modeled ozone does not always agree with observations. A complementary approach is to measure the ozone production rate directly, leading to the development of the Measurement of Ozone Production Sensor (MOPS). Two improved second-generation MOPSv2s were deployed for NASA's DISCOVER-AQ field campaign in September 2013 at the University of Houston, 5 km south of downtown, and Smith Point, at the mouth of the Houston Ship Channel. Median September P(O3) was low, consistent with the observed ambient ozone. The MOPSv2s provided statistically similar results when they were compared for 8 day sat the University of Houston. October measurements yielded a median ozone production rate of 27 ± 11 ppbv hr-1, falling within the range of calculated P(O3) from prior Houston field campaigns in 2006 and 2009. Additionally, diurnal patterns are similar to model-derived ozone production from these previous campaigns. An advection analysis for a high ozone event on 25 September 2013 indicates that the Houston site was in a local ozone source region, while Smith Point ozone was likely enhanced by transport from other areas.

  3. Ozone Depletion from Nearby Supernovae

    NASA Technical Reports Server (NTRS)

    Gehrels, Neil; Laird, Claude M.; Jackman, Charles H.; Cannizzo, John K.; Mattson, Barbara J.; Chen, Wan; Bhartia, P. K. (Technical Monitor)

    2002-01-01

    Estimates made in the 1970's indicated that a supernova occurring within tens of parsecs of Earth could have significant effects on the ozone layer. Since that time improved tools for detailed modeling of atmospheric chemistry have been developed to calculate ozone depletion, and advances have been made also in theoretical modeling of supernovae and of the resultant gamma ray spectra. In addition, one now has better knowledge of the occurrence rate of supernovae in the galaxy, and of the spatial distribution of progenitors to core-collapse supernovae. We report here the results of two-dimensional atmospheric model calculations that take as input the spectral energy distribution of a supernova, adopting various distances from Earth and various latitude impact angles. In separate simulations we calculate the ozone depletion due to both gamma rays and cosmic rays. We find that for the combined ozone depletion from these effects roughly to double the 'biologically active' UV flux received at the surface of the Earth, the supernova must occur at approximately or less than 8 parsecs.

  4. 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

  5. Observations of ozone depletion associated with solar proton events

    NASA Technical Reports Server (NTRS)

    Mcpeters, R. D.; Jackman, C. H.; Stassinopoulos, E. G.

    1981-01-01

    Ozone profiles from the solar proton events (SPE) of January and September 1971 and August 1972 were obtained after the backscattered ultraviolet (BUV) measured radiances were corrected for the direct effects of protons on the instrument. The SPE of August 1972 produced an ozone depletion of 15% at 42 km that persisted for one month in both northern and southern polar regions. This long recovery time indicates that NO(x) was produced in a quantity sufficient to alter the ozone chemistry. The two SPE in 1971 were of moderate size, but produced ozone depletions of 10-30% at 50 km with a 36 hour recovery time. This rapid recovery is consistent with the assumption that HO(x) is responsible for altering the ozone chemistry (Weeks et al., 1972). The magnitude of the observed depletion, however, exceeds that predicted by the chemical models.

  6. Technical note: Examining ozone deposition over seawater

    NASA Astrophysics Data System (ADS)

    Sarwar, Golam; Kang, Daiwen; Foley, Kristen; Schwede, Donna; Gantt, Brett; Mathur, Rohit

    2016-09-01

    Surface layer resistance plays an important role in determining ozone deposition velocity over sea-water and can be influenced by chemical interactions at the air-water interface. Here, we examine the effect of chemical interactions of iodide, dimethylsulfide, dissolved organic carbon, and bromide in seawater on ozone deposition. We perform a series of simulations using the hemispheric Community Multiscale Air Quality model for summer months in the Northern Hemisphere. Our results suggest that each chemical interaction enhances the ozone deposition velocity and decreases the atmospheric ozone mixing ratio over seawater. Iodide enhances the median deposition velocity over seawater by 0.023 cm s-1, dissolved organic carbon by 0.021 cm s-1, dimethylsulfide by 0.002 cm s-1, and bromide by ∼0.0006 cm s-1. Consequently, iodide decreases the median atmospheric ozone mixing ratio over seawater by 0.7 ppb, dissolved organic carbon by 0.8 ppb, dimethylsulfide by 0.1 ppb, and bromide by 0.02 ppb. In a separate model simulation, we account for the effect of dissolved salts in seawater on the Henry's law constant for ozone and find that it reduces the median deposition velocity by 0.007 cm s-1 and increases surface ozone mixing ratio by 0.2 ppb. The combined effect of these processes increases the median ozone deposition velocity over seawater by 0.040 cm s-1, lowers the atmospheric ozone mixing ratio by 5%, and slightly improves model performance relative to observations.

  7. ADVANCED OXIDATION: OXALATE DECOMPOSITION TESTING WITH OZONE

    SciTech Connect

    Ketusky, E.; Subramanian, K.

    2012-02-29

    dissolution equilibrium, and then decomposed to {le} 100 Parts per Million (ppm) oxalate. Since AOP technology largely originated on using ultraviolet (UV) light as a primary catalyst, decomposition of the spent oxalic acid, well exposed to a medium pressure mercury vapor light was considered the benchmark. However, with multi-valent metals already contained in the feed, and maintenance of the UV light a concern; testing was conducted to evaluate the impact from removing the UV light. Using current AOP terminology, the test without the UV light would likely be considered an ozone based, dark, ferrioxalate type, decomposition process. Specifically, as part of the testing, the impacts from the following were investigated: (1) Importance of the UV light on the decomposition rates when decomposing 1 wt% spent oxalic acid; (2) Impact of increasing the oxalic acid strength from 1 to 2.5 wt% on the decomposition rates; and (3) For F-area testing, the advantage of increasing the spent oxalic acid flowrate from 40 L/min (liters/minute) to 50 L/min during decomposition of the 2.5 wt% spent oxalic acid. The results showed that removal of the UV light (from 1 wt% testing) slowed the decomposition rates in both the F & H testing. Specifically, for F-Area Strike 1, the time increased from about 6 hours to 8 hours. In H-Area, the impact was not as significant, with the time required for Strike 1 to be decomposed to less than 100 ppm increasing slightly, from 5.4 to 6.4 hours. For the spent 2.5 wt% oxalic acid decomposition tests (all) without the UV light, the F-area decompositions required approx. 10 to 13 hours, while the corresponding required H-Area decompositions times ranged from 10 to 21 hours. For the 2.5 wt% F-Area sludge, the increased availability of iron likely caused the increased decomposition rates compared to the 1 wt% oxalic acid based tests. In addition, for the F-testing, increasing the recirculation flow rates from 40 liter/minute to 50 liter/minute resulted in an

  8. Advanced treatment of biotreated textile industry wastewater with ozone, virgin/ozonated granular activated carbon and their combination.

    PubMed

    Arslan-Alaton, Idil; Seremet, Ozden

    2004-01-01

    Biotreated textile wastewater (CODo = 248 mg L(-1); TOCo = 58 mg L(-1); A620 = 0.007 cm(-1); A525 = 0.181 cm(-1); A436 = 0.198 cm(-1)) was subjected to advanced treatment with ozonation, granular activated carbon (GAC) adsorption in serial and simultaneous applications. Experiments were conducted to investigate the effects of applied ozone dose, ozone absorption rate, specific ozone absorption efficiency, GAC dose, and reaction pH on the treatment performance of the selected tertiary treatment scheme. In separate experiments, the impact of virgin GAC ozonation on its adsorptive capacity for biotreated and biotreated + ozonated textile effluent was also investigated. Ozonation appeared to be more effective for decolorization (kd = 0.15 min(-1) at pH = 3), whereas GAC adsorption yielded higher COD removal rates (54% at pH = 3). It was also found that GAC addition (4 g/L) at pH = 7 and 9 enhanced the COD abatement rate of the ozonation process significantly and that the sequential application of ozonation (at pH = 3-11, 675 mg L(-1) O3) followed by GAC adsorption (at pH = 3-7, 10 g L(-1) GAC) resulted in the highest treatment performances both in terms of color and COD reduction. Simultaneous application of GAC and ozone at acidic and alkaline pH seriously inhibited COD abatement rates as a consequence of competitive adsorption and partial oxidation of textile components and GAC. It could also be established that ozone absorption efficiency decreased after color removal was complete. Ozonation of biotreated textile wastewater with 113 mg L(-1) ozone resulted in an appreciable enhancement of GAC adsorptive capacity in terms of residual color removal. Ozonation of GAC at relatively low doses (= 10.8 mg/g GAC) did not improve its overall adsorption capacity.

  9. The Swedish duty hour enigma

    PubMed Central

    2014-01-01

    Background The Swedish resident duty hour limit is regulated by Swedish and European legal frameworks. With a maximum average of 40 working hours per week, the Swedish duty hour regulation is one of the most restrictive in the world. At the same time, the effects of resident duty hour limits have been neither debated nor researched in the Swedish context. As a result, little is known about the Swedish conceptual framework for resident duty hours, their restriction, or their outcomes: we call this “the Swedish duty hour enigma.” This situation poses a further question: How do Swedish residents themselves construct a conceptual framework for duty hour restrictions? Methods A case study was conducted at Karolinska University Hospital, Stockholm – an urban, research-intensive hospital setting. Semi-structured interviews were carried out with 34 residents currently in training in 6 specialties. The empirical data analysis relied on theoretical propositions and was conducted thematically using a pattern-matching technique. The interview guide was based on four main topics: the perceived effect of duty hour restrictions on (1) patient care, (2) resident education, (3) resident well-being, and (4) research. Results The residents did not perceive the volume of duty hours to be the main determinant of success or failure in the four contextual domains of patient care, resident education, resident well-being, and research. Instead, they emphasized resident well-being and a desire for flexibility. Conclusions According to Swedish residents’ conceptual framework on duty hours, the amount of time spent on duty is not a proxy for the quality of resident training. Instead, flexibility, organization, and scheduling of duty hours are considered to be the factors that have the greatest influence on resident well-being, quality of learning, and opportunities to attain the competence needed for independent practice. PMID:25559074

  10. [Effects of synoptic type on surface ozone pollution in Beijing].

    PubMed

    Tang, Gui-qian; Li, Xin; Wang, Xiao-ke; Xin, Jin-yuan; Hu, Bo; Wang, Li-li; Ren, Yu-fen; Wang, Yue-Si

    2010-03-01

    Ozone (O), influenced by meteorological factors, is a primary gaseous photochemical pollutant during summer to fall in Beijing' s urban ambient. Continuous monitoring during July to September in 2008 was carried out at four sites in Beijing. Analyzed with synoptic type, the results show that the ratios of pre-low cylonic (mainly Mongolia cyclone) and pre-high anticylonic to total weather conditions are about 42% and 20%, illustrating the high-and low-ozone episodes, respectively. At the pre-low cylonic conditions, high temperature, low humidity, mountain and valley winds caused by local circulation induce average hourly maximum ozone concentration (volume fraction) up to 102.2 x 10(-9), negative correlated with atmospheric pressure with a slope of -3.4 x 10(-9) Pa(-1). The time of mountain wind changed to valley wind dominates the diurnal time of maximum ozone, generally around 14:00. At the pre-high anticylonic conditions, low temperature, high humidity and systematic north wind induce average hourly maximum ozone concentration (volume fraction) only 49.3 x 10(-9), the diurnal time of maximum ozone is deferred by continuous north wind till about 16:00. The consistency of photochemical pollution in Beijing region shows that good correlation exists between synoptic type and ozone concentration. Therefore, getting an eye on the structure and evolution of synoptic type is of great significances for forecasting the photochemical pollution.

  11. Biochemical Plant Responses to Ozone 1

    PubMed Central

    Rosemann, Detlef; Heller, Werner; Sandermann, Heinrich

    1991-01-01

    Formation of the stilbenes pinosylvin and pinosylvin 3-methyl ether, as well as the activity of the biosynthetic enzyme stilbene synthase (pinosylvin-forming), were induced several hundred- to thousandfold in primary needles of 6-week-old pine (Pinus sylvestris L.) seedlings upon exposure to a single pulse of ozone of at least 0.15 microliters per liter. The seedlings required 4 hours of exposure as a minimum for the induction of stilbene biosynthesis when exposed to 0.2 microliters per liter ozone. Both stilbene synthase activity and stilbene accumulation increased with the duration of ozone treatment. The activity of phenylalanine ammonia-lyase and the activity of chalcone synthase, a key enzyme of the flavonoid pathway that uses the same substrates as stilbene synthase, were also stimulated about twofold by ozone. Stilbene biosynthesis appears to represent the first example of a dose-dependent biochemical response to ozone in a conifer species and may serve as a useful biomarker to study stress impacts on pine trees. PMID:16668544

  12. [Ozone exposure and asthma].

    PubMed

    Kleis, S; Louis, R; Bartsch, P

    2003-03-01

    Ozone is a pollutant the production of which depends on weather conditions and car engine combustion. Numerous epidemiological studies have indicated that high ozone levels correlated with morbidity in asthma. Experimental studies have shown that exposure of healthy subjects and asthmatics to ozone levels comparable to those measured in ambient air during hot summer days can generate respiratory symptoms, neutrophilic airways inflammation and lung function impairment. Lung function changes following ozone exposure are more pronounced in asthmatics and are dependent on the duration and intensity of exposure, a previous exposure and the nutritional status of the subjects. The airway epithelial cell layer is likely to play a pivotal role in initiating the inflammatory process following ozone exposure. Control of ambient air ozone levels must be a target for public health authorities.

  13. Biological effects of ozone

    SciTech Connect

    Lippmann, M. )

    1989-09-01

    Tropospheric ozone, a classic anthropogenic air pollutant, is going to remain a troublesome byproduct of contemporary civilization for many decades. We have known for some time that the hydrocarbons and nitrogen oxides from motor vehicles, together with actinic radiation, account for local and regional photochemistry leading to prolonged afternoon ozone peaks. We also now know that agricultural burning and intensive animal husbandry elevate regional and mesoscale concentrations of ozone and its precursors, and that remote background levels of ozone have been rising steadily throughout this century. The changes we will have to make in emission controls to appreciably reduce current tropospheric ozone levels will have profound effects on our transportation systems, consumer products, and lifestyles. As a society, we will have to make difficult choices about the levels of ozone-associated health, welfare, and natural system damage we will tolerate, or conversely, how much we are willing to pay for controls which can minimize the damage.

  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. 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.

  16. Accreditation and the Credit Hour.

    ERIC Educational Resources Information Center

    Wellman, James V.

    2003-01-01

    Reviews the role that accreditation plays in defining and enforcing the credit-hour measure. Regional accreditation agencies are generally more flexible in terms of defining credit hours than are national agencies, which are more rigid in their expectations. Specialized accrediting agencies usually make the least mention of credit units. (SLD)

  17. Is the Office Hour Obsolete?

    ERIC Educational Resources Information Center

    Behrens, Susan

    2013-01-01

    A colleague can't make a coffee date at a time the author proposes because it would conflict with his office hour. No student has actually made an appointment with him during the hour, but he is committed to being in his office as promised in case someone drops by. The author's reaction to her colleague's faithfulness to his posted office hour…

  18. Breaking the Long Hours Culture.

    ERIC Educational Resources Information Center

    Kodz, J.; Kersley, B.; Strebler, M. T.; O'Regan, S.

    Case studies of 12 leading British employers were driven by employers' interest in issues related to working long hours in light of introduction of the Working Time Directive, a European Community initiative enacted into British law that sets limits on working hours per week. Data showed over one-fourth of full-time employees worked over 48 hours…

  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. Changes in stratospheric ozone.

    PubMed

    Cicerone, R J

    1987-07-01

    The ozone layer in the upper atmosphere is a natural feature of the earth's environment. It performs several important functions, including shielding the earth from damaging solar ultraviolet radiation. Far from being static, ozone concentrations rise and fall under the forces of photochemical production, catalytic chemical destruction, and fluid dynamical transport. Human activities are projected to deplete substantially stratospheric ozone through anthropogenic increases in the global concentrations of key atmospheric chemicals. Human-induced perturbations may be occurring already.

  1. Role of Methane in Antarctic Stratospheric Ozone Recovery

    NASA Astrophysics Data System (ADS)

    Calvo, Natalia; Kinnison, Douglas E.; Marsh, Daniel R.; Garcia, Rolando R.; Palmeiro, Froila

    2014-05-01

    Observational and modeling studies have shown the impact of changes in Antarctic stratospheric ozone on tropospheric climate in austral spring and summer. In the future, effects of increasing greenhouse gases and ozone depleting substances oppose each other. Projections show potential impact of ozone recovery on precipitation, carbon uptake in the Southern Hemisphere ocean, Antarctic ice sheets and Southern Hemisphere sea ice. In order to quantify properly the tropospheric impacts of ozone recovery, future Antarctic ozone changes in the upper troposphere lower stratosphere region and the role (if any) of increasing greenhouse gases in ozone recovery need to be evaluated. To do so, we use the National Center for Atmospheric Research's Community Earth System Model, CESM, with the high-top version of the atmospheric component, CESM(WACCM), which is a fully coupled chemistry climate model. Three climate change scenarios (RCP2.6, RCP4.5 and RCP8.5) of 3 simulations each from 2005 to 2065 are analyzed. In scenario RCP2.6, the largest ozone recovery is simulated in October and November at 50hPa and it is followed by the largest response in temperature in November and December at 70hPa. While the response in RCP4.5 in ozone and temperature is almost identical to that in RCP2.6 in the upper troposphere and lower stratosphere region, scenario RCP8.5 shows significantly stronger ozone recovery and warming than the other two scenarios, particularly in November and December at 70hPa in ozone and 100hPa in temperature. We show that this is due to larger amounts of methane in RCP8.5 compared to the other two scenarios, which reduces catalytic ozone loss locally. Differences across scenarios in advection of ozone from the source region in the tropical stratosphere do not play a significant role.

  2. Nicotiana tabacum as model for ozone - plant surface reactions

    NASA Astrophysics Data System (ADS)

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

    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 billion dollars per year. The ensuing injuries have been related to the uptake of ozone through the stomatal pores and oxidative effects damaging the internal leaf tissue. A striking question of current research is the environment and plant specific partitioning of ozone loss between gas phase, stomatal or plant surface sink terms. Here we show results from ozone fumigation experiments using various Nicotiana Tabacum varieties, whose surfaces are covered with different amounts of unsaturated diterpenoids exuded by their glandular trichomes. Exposure to elevated ozone levels (50 to 150 ppbv) for 5 to 15 hours in an exceptionally clean cuvette system did neither result in a reduction of photosynthesis nor caused any visible leaf damage. Both these ozone induced stress effects have been observed previously in ozone fumigation experiments with the ozone sensitive tobacco line Bel-W3. In our case ozone fumigation was accompanied by a continuous release of oxygenated volatile organic compounds, which could be clearly associated to their condensed phase precursors for the first time. Gas phase reactions of ozone were avoided by choosing a high enough gas exchange rate of the plant cuvette system. In the case of the Ambalema variety, that is known to exude only the diterpenoid cis-abienol, ozone fumigation experiments yield the volatiles formaldehyde and methyl vinyl ketone (MVK). The latter could be unequivocally separated from isomeric methacrolein (MACR) by the aid of a Selective Reagent Ion Time-of-Flight Mass Spectrometer (SRI-ToF-MS), which was switched every six minutes from H3O+ to NO+ primary ion mode and vice versa. Consistent with the picture of an ozone protection mechanism caused by reactive diterpenoids at the leaf surface are the results from dark-light experiments. The ozone loss obtained from the

  3. Stratospheric Ozone in the Post-CFC Era

    NASA Technical Reports Server (NTRS)

    Li, Feng; Solarski, Richard S.; Newman, Paul A.

    2008-01-01

    Vertical and latitudinal changes in the stratospheric ozone in the post-chlorofluorocarbon (CFC) era are investigated using simulations of the recent past and the 21st century with a coupled chemistry-climate model. Model results reveal that, in the 2060s when the stratospheric halogen loading is projected to return to its 1980 values, the extratropical column ozone is significantly higher than that in 1975-1984, but the tropical column ozone does not recover to 1980 values. Upper and lower stratospheric ozone changes in the post- CFC era have very different patterns. Above 15 hPa ozone increases almost latitudinally uniformly by 6 Dobson Unit (DU), whereas below 15 hPa ozone decreases in the tropics by 8 DU and increases in the extratropics by up to 16 DU. The upper stratospheric ozone increase is a photochemical response to greenhouse gas induced strong cooling, and the lower stratospheric ozone changes are consistent with enhanced mean advective transport due to a stronger Brewer-Dobson circulation. The model results suggest that the strengthening of the Brewer-Dobson circulation plays a crucial role in ozone recovery and ozone distributions in the post-CFC era.

  4. Stratospheric ozone in the post-CFC era

    NASA Astrophysics Data System (ADS)

    Li, F.; Stolarski, R. S.; Newman, P. A.

    2008-12-01

    Vertical and latitudinal changes in the stratospheric ozone in the post-chlorofluorocarbon (CFC) era are investigated using simulations of the recent past and the 21st century with a coupled chemistry-climate model. Model results reveal that, in the 2060s when the stratospheric halogen loading is projected to return to its 1980 values, the extratropical column ozone is significantly higher than that in 1975-1984, but the tropical column ozone does not recover to 1980 values. Upper and lower stratospheric ozone changes in the post-CFC era have very different patterns. Above 15 hPa ozone increases almost latitudinally uniformly by 6 Dobson Unit (DU), whereas below 15 hPa ozone decreases in the tropics by 8 DU and increases in the extratropics by up to 16 DU. The upper stratospheric ozone increase is a photochemical response to greenhouse gas induced strong cooling, and the lower stratospheric ozone changes are consistent with enhanced mean advective transport due to a stronger Brewer-Dobson circulation. The model results suggest that the strengthening of the Brewer-Dobson circulation plays a crucial role in ozone recovery and ozone distributions in the post-CFC era.

  5. Stratospheric ozone in the post-CFC era

    NASA Astrophysics Data System (ADS)

    Li, F.; Stolarski, R. S.; Newman, P. A.

    2009-03-01

    Vertical and latitudinal changes in the stratospheric ozone in the post-chlorofluorocarbon (CFC) era are investigated using simulations of the recent past and the 21st century with a coupled chemistry-climate model. Model results reveal that, in the 2060s when the stratospheric halogen loading is projected to return to its 1980 values, the extratropical column ozone is significantly higher than that in 1975-1984, but the tropical column ozone does not recover to 1980 values. Upper and lower stratospheric ozone changes in the post-CFC era have very different patterns. Above 15 hPa ozone increases almost latitudinally uniformly by 6 Dobson Unit (DU), whereas below 15 hPa ozone decreases in the tropics by 8 DU and increases in the extratropics by up to 16 DU. The upper stratospheric ozone increase is a photochemical response to greenhouse gas induced strong cooling, and the lower stratospheric ozone changes are consistent with enhanced mean advective transport due to a stronger Brewer-Dobson circulation. The model results suggest that the strengthening of the Brewer-Dobson circulation plays a crucial role in ozone recovery and ozone distributions in the post-CFC era.

  6. Stratospheric Ozone in the Post-CFC Era

    NASA Technical Reports Server (NTRS)

    Li, F.; Stolarski, R. S.; Newman, P. A.

    2009-01-01

    Vertical and latitudinal changes in the stratospheric ozone in the post-chlorofluorocarbon (CFC) era are investigated using simulations of the recent past and the 21st century with a coupled chemistry-climate model. Model results reveal that, in the 2060s when the stratospheric halogen loading is projected to return to its 1980 values, the extratropical column ozone is significantly higher than that in 1975-1984, but the tropical column ozone does not recover to 1980 values. Upper and lower stratospheric ozone changes in the post-CFC era have very different patterns. Above 15 hPa ozone increases almost latitudinally uniformly by 6 Dobson Unit (DU), whereas below 15 hPa ozone decreases in the tropics by 8 DU and increases in the extratropics by up to 16 DU. The upper stratospheric ozone increase is a photochemical response to greenhouse gas induced strong cooling, and the lower stratospheric ozone changes are consistent with enhanced mean advective transport due to a stronger Brewer-Dobson circulation. The model results suggest that the strengthening of the Brewer-Dobson circulation plays a crucial role in ozone recovery and ozone distributions in the post-CFC era.

  7. Adsorption air cleaning from ozone.

    PubMed

    Baltrenas, Pranas; Paliulis, Dainius; Vasarevicius, Saulius; Simaitis, Ramutis

    2003-01-01

    Not much has been written about air cleaning from ozone. The aim of this paper was to demonstrate the possibility of adsorption air cleaning from ozone. The second aim was to investigate the dependence of the efficiency of ozone removal from the air on the height of the adsorber layer and on concentrations of ozone, and to obtain empirical formulas for calculating the efficiency of ozone treatment. Equipment for air cleaning from ozone and nitrogen and sulphur dioxides is suggested.

  8. Ozone-induced modulation of airway hyperresponsiveness in guinea pigs.

    PubMed

    Schlesinger, Richard B; Cohen, Mitchell; Gordon, Terry; Nadziejko, Christine; Zelikoff, Judith T; Sisco, Maureen; Regal, Jean F; Ménache, Margaret G

    2002-06-01

    Although acute exposure to ozone (03*) has been shown to influence the severity and prevalence of airway hyperresponsiveness, information has been lacking on effects due to long-term exposure at relatively low exposure concentrations. The goals of this study were to determine whether long-term repeated ozone exposures could induce nonspecific hyperresponsiveness in normal, nonatopic (nonsensitized) animals, whether such exposure could exacerbate the preexisting hyperresponsive state in atopic (sensitized) animals, or both. The study was also designed to determine whether gender modulated airway responsiveness related to ozone exposure. Airway responsiveness was measured during and after exposure to 0.1 and 0.3 ppm ozone for 4 hours/day, 4 days/week for 24 weeks in normal, nonsensitized guinea pigs, in guinea pigs sensitized to an allergen (ovalbumin) prior to initiation of ozone exposures, and in animals sensitized concurrently with ozone exposures. Both male and female animals were studied. Ozone exposure did not produce airway hyperresponsiveness in nonsensitized animals. Ozone exposure did exacerbate airway hyperresponsiveness to specific and nonspecific bronchoprovocation in both groups of sensitized animals, and this effect persisted at least 4 weeks after the end of the exposures. Although the overall degree of airway responsiveness did differ between genders (males had more responsive airways than did females), the airway response to ozone exposure did not differ between the two groups. Ozone-induced effects upon airway responsiveness were not associated with the number of pulmonary eosinophils or with any chronic pulmonary inflammatory response. Levels of antigen-specific antibodies increased in sensitized animals, and a significant correlation was observed between airway responsiveness and antibody levels. The results of this study provide support for a role of ambient ozone exposure in exacerbation of airway dysfunction in persons with atopy.

  9. Lower Boundary Layer and Ozone Profiles Over Fresno during Wildfire Events

    NASA Astrophysics Data System (ADS)

    Ogunjemiyo, S. O.; Omolayo, S. A.

    2010-12-01

    Ozone is a secondary pollutant in the troposphere that is largely formed as a result of photolytic reactions related to ozone precursors such as methane (CH4), carbon monoxide (CO), nitrogen oxides (NOx) and VOCs (Volatile Organic Compounds like isoprene, benzene etc.). Hence, processes and factors regulating emissions of ozone precursors are important in controlling spatial and temporal variation of ozone concentrations. Giving favorable meteorological conditions, large scale wildfires in fuel rich areas have been recognized for their potential to significantly affect the regional and global distributions of tropospheric O3, and also increases the background surface ozone concentrations above the NAAQS level, even in areas that may be hundreds of miles away from wildfire locations. Improving regional ozone forecast thus requires not only the knowledge of the amount of ozone precursors released into the atmosphere and ozone produced during wildfires, but also information on boundary layer dynamics and vertical ozone transport. In this study effort is made to characterize ozone transport in the lower urban boundary layer during wildfire events. In this regard, tethersonde and ozonesonde measurements were made over Fresno California in the period the region was affected by smoke particles from the Moonlight fire in September 2007 and the Telegraph fire in July 2008. Analysis of the profiles data showed that the Fresno Eddy, in addition to boundary layer dynamics, particularly the down mixing of high ozone concentration in the residual boundary layer, were significant factors influencing hourly measured ground level ozone concentration at the site.

  10. Ozone Hole Airborne Arctic Stratospheric Expedition (Pre-Flight)

    NASA Technical Reports Server (NTRS)

    1989-01-01

    The first segment of this video gives an overview of the Ozone Hole Airborne Arctic Stratospheric Expedition, an international effort using balloon payloads, ground based instruments, and airborne instruments to study ozone depletion and the hole in the ozone over Antarctica which occurs every spring. False color imagery taken from NASA's Nimbus 7 satellite which documents daily changes in ozone is also shown. The second segment of this video shows actual take-off and flight footage of the two aircraft used in the experiment: the DC-8 Flying Laboratory and the high flying ER-2.

  11. Ozone decay on stainless steel and sugarcane bagasse surfaces

    NASA Astrophysics Data System (ADS)

    Souza-Corrêa, Jorge A.; Oliveira, Carlos; Amorim, Jayr

    2013-07-01

    Ozone was generated using dielectric barrier discharges at atmospheric pressure to treat sugarcane bagasse for bioethanol production. It was shown that interaction of ozone molecules with the pretreatment reactor wall (stainless steel) needs to be considered during bagasse oxidation in order to evaluate the pretreatment efficiency. The decomposition coefficients for ozone on both materials were determined to be (3.3 ± 0.2) × 10-8 for stainless steel and (2.0 ± 0.3) × 10-7 for bagasse. The results have indicated that ozone decomposition has occurred more efficiently on the biomass material.

  12. Lidar-derived Correlations Between Lower-tropospheric Column and Surface Ozone: Implications for Satellite Observations

    NASA Astrophysics Data System (ADS)

    Senff, C. J.; Langford, A. O.; Alvarez, R. J. _II, II; Kirgis, G.; Choukulkar, A.; Brewer, A.; Banta, R. M.; Weickmann, A. M.; Sandberg, S.; Olson, E.

    2015-12-01

    One of the data products that will be provided by the TEMPO satellite mission is 0-2 km ozone column concentration. To make inferences about surface air quality from this data product, the relationship between lower-tropospheric column and surface ozone concentrations and their diurnal, seasonal, and spatial variations have to be well understood. To characterize these relationships, we have used ozone profile observations obtained with NOAA's truck-based, scanning TOPAZ ozone lidar from several recent field campaigns including Discover-AQ Houston and Colorado, the Uintah Basin Wintertime Ozone Study (UBWOS), and the Las Vegas Ozone Study (LVOS). The TOPAZ lidar is ideally suited for this kind of study because it provides ozone profiles from about 15 m above ground level (AGL) up to 3 km AGL at high spatial and temporal resolution. We have used the lidar observations closest to the ground as a proxy for surface ozone and compared them to the 0-2 km AGL average column ozone concentrations measured with the lidar. Results from the Discover-AQ Colorado campaign show that in the afternoon, when the boundary layer (BL) was deep and well mixed, ozone column and surface concentrations agreed quite well. However, during the morning hours, ozone column concentrations were significantly higher than those at the surface, because ozone was depleted in a shallow surface layer due to titration and deposition, whereas ozone levels in the residual layer aloft remained moderately high. The analysis of column and surface ozone correlations using ozone lidar observations from the Discover-AQ Houston, UBWOS and LVOS campaigns is currently underway. The results from these studies will provide additional insights into the relationship between column and surface ozone, in particular their variation as a function of measurement location and season, and their dependence on BL processes such as mixed layer height evolution, land-sea breeze circulation, and terrain-induced flows.

  13. 40 CFR 52.2235 - Control strategy: Ozone.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    .... This determination, in accordance with 40 CFR 51.918, suspends the requirements for this area to submit... 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...

  14. 40 CFR 52.2235 - Control strategy: Ozone.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    .... This determination, in accordance with 40 CFR 51.918, suspends the requirements for this area to submit... 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...

  15. 40 CFR 52.2235 - Control strategy: Ozone.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    .... This determination, in accordance with 40 CFR 51.918, suspends the requirements for this area to submit... 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...

  16. 40 CFR 52.2235 - Control strategy: Ozone.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    .... This determination, in accordance with 40 CFR 51.918, suspends the requirements for this area to submit... 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...

  17. CONTENDING WITH SPACE-TIME INTERACTION IN THE SPATIAL PREDICTION OF POLLUTION: VANCOUVER'S HOURLY AMBIENT PM 10 FIELD

    EPA Science Inventory

    In this article we describe an approach for predicting average hourly concentrations of ambient PM10 in Vancouver. We know our solution also applies to hourly ozone fields and believe it may be quite generally applicable. We use a hierarchal Bayesian approach. At the primary ...

  18. 48 CFR 211.271 - Elimination of use of class I ozone-depleting substances.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... class I ozone-depleting substances. 211.271 Section 211.271 Federal Acquisition Regulations System... Using and Maintaining Requirements Documents 211.271 Elimination of use of class I ozone-depleting substances. See subpart 223.8 for restrictions on contracting for ozone-depleting substances....

  19. 48 CFR 211.271 - Elimination of use of class I ozone-depleting substances.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... class I ozone-depleting substances. 211.271 Section 211.271 Federal Acquisition Regulations System... Using and Maintaining Requirements Documents 211.271 Elimination of use of class I ozone-depleting substances. See subpart 223.8 for restrictions on contracting for ozone-depleting substances....

  20. 48 CFR 211.271 - Elimination of use of class I ozone-depleting substances.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... class I ozone-depleting substances. 211.271 Section 211.271 Federal Acquisition Regulations System... Using and Maintaining Requirements Documents 211.271 Elimination of use of class I ozone-depleting substances. See subpart 223.8 for restrictions on contracting for ozone-depleting substances....

  1. 48 CFR 211.271 - Elimination of use of class I ozone-depleting substances.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... class I ozone-depleting substances. 211.271 Section 211.271 Federal Acquisition Regulations System... Using and Maintaining Requirements Documents 211.271 Elimination of use of class I ozone-depleting substances. See subpart 223.8 for restrictions on contracting for ozone-depleting substances....

  2. 48 CFR 211.271 - Elimination of use of class I ozone-depleting substances.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... class I ozone-depleting substances. 211.271 Section 211.271 Federal Acquisition Regulations System... Using and Maintaining Requirements Documents 211.271 Elimination of use of class I ozone-depleting substances. See subpart 223.8 for restrictions on contracting for ozone-depleting substances....

  3. Alternative ozone metrics and daily mortality in Suzhou: the China Air Pollution and Health Effects Study (CAPES).

    PubMed

    Yang, Chunxue; Yang, Haibing; Guo, Shu; Wang, Zongshuang; Xu, Xiaohui; Duan, Xiaoli; Kan, Haidong

    2012-06-01

    Controversy remains regarding the relationship between various metrics of ozone (O(3)) and mortality. In China, the largest developing country, there have been few studies investigating the acute effect of O(3) on death. We used three exposure metrics of O(3) (1-hour maximum, maximum 8-hour average and 24-hour average) to examine its short-term association with daily mortality in Suzhou, China. We used a Generalized Additive Model (GAM) with penalized splines to analyze the mortality, O(3), and covariate data. We examined the association by season, age group, sex and educational level. We found that the current level of O(3) in Suzhou is associated with death rates from all causes and cardiovascular diseases. Among various metrics of O(3), maximum 8-hour average and 1-hour maximum concentrations seem to be more strongly associated with increased mortality rate compared to 24-hour average concentrations. Using maximum 8-hour average, an inter-quartile range increase of 2-day average O(3) (lag 01) corresponds to 2.15% (95%CI, 0.36 to 3.93), 4.47% (95%CI, 1.43 to 7.51), -1.85% (95%CI, -6.91 to 3.22) increase in all-cause, cardiovascular, and respiratory mortality, respectively. The associations between O(3) and daily mortality appeared to be more evident in the cool season than in the warm season. In conclusion, maximum 8-hour average and 1-hour maximum concentrations of O(3) are associated with daily mortality in Suzhou. Our analyses strengthen the rationale for further limiting levels of O(3) pollution in the city. PMID:22521098

  4. Yearly variation and annual cycle of total column ozone over New Delhi (29°N, 77°E), India and Halley Bay (76°S, 27°W), British Antarctic Survey Station and its effect on night airglow intensity of OH(8, 3) for the period 1979-2005

    NASA Astrophysics Data System (ADS)

    Jana, P. K.; Saha, D. K.; Sarkar, D.

    2012-12-01

    A critical analysis made on the long-term monthly, seasonal, yearly variation and annual cycle of total column ozone (TCO) concentration at New Delhi (29°N, 77°E), India and Halley Bay (76°S, 27°W), a British Antarctic Service Station reveals more decline in yearly mean ozone concentration at Halley Bay than at New Delhi from 1979 to 2005. The nature of variations of monthly mean TCO during the months of August and September was the most identical with that of yearly mean ozone values at New Delhi and Halley Bay, respectively, for the same period. Annual cycles of TCO over these stations are completely different for the above period. The effect of O3 depletion on night airglow emission of OH(8, 3) line at New Delhi and Halley Bay has been studied. Calculations based on chemical kinetics show that the airglow intensity of OH(8, 3) has also been affected due to the depletion of O3 concentration. The yearly variations and annual cycle of intensities of OH(8, 3) line for the above two stations are depicted and compared. It has been shown that the rate of decrease of intensity of OH(8, 3) line was comparatively more at Halley Bay due to dramatic decrease of Antarctic O3 concentration.

  5. Tropospheric ozone variability over the Iberian Peninsula

    NASA Astrophysics Data System (ADS)

    Kulkarni, Pavan S.; Bortoli, D.; Salgado, R.; Antón, M.; Costa, M. J.; Silva, A. M.

    2011-01-01

    To study tropospheric ozone variability over the Iberian Peninsula (IP), NASA Langley TOR data have been analyzed for the 1979-2005 period. The maximum tropospheric ozone concentration over the entire IP was found in June (˜41 DU) and a minimum in December (˜29 DU). However the maximum tropospheric ozone concentration was found over West Atlantic Coast (WAC) (˜44 DU), followed by Mediterranean Coast (MC) (˜42 DU), North Atlantic Coast (NAC) (˜41 DU), Central Iberian Peninsula (CIP) (˜40 DU) and Pyrenees Mountain Range (PMR) (˜39 DU) during June-July. The high concentration of tropospheric ozone in July over the Atlantic Ocean near IP is due to the presence of Azores anticyclone and related photochemistry and dynamics, and affects the observed higher tropospheric ozone concentration over WAC zone. Strong seasonal cycle in tropospheric ozone concentration has been observed with large variation over NAC (˜49%), followed by WAC (˜48%) and MC (˜41%) compared to CIP and PMR (˜38%) zones. When the data are compared over the IP for the two periods (1979-1993 and 1997-2005), a systematic increase in the number of months with higher tropospheric ozone concentration has been observed during the second period with respect to the first. These increases are almost 8% to 24% over NAC, 6% to 17% over WAC, 5% to 24% over CIP, 6% to 23% over MC and 13% to 18% over PMR, zones. It has been observed that topography, climatology and population density distribution plays a crucial role in the variability of tropospheric ozone concentration over the IP.

  6. The role of bay breezes and regional transport on a high surface ozone episode during the Houston, Texas DISCOVER-AQ field campaign

    NASA Astrophysics Data System (ADS)

    Loughner, C.; Follette-Cook, M. B.; Pickering, K. E.; Estes, M. J.

    2014-12-01

    The highest observed surface ozone concentrations in the Houston metropolitan area in 2013 occurred on September 25, which coincided with the Texas DISCOVER-AQ (Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality) field campaign. Surface ozone was elevated throughout the Houston metropolitan area. Maximum 8-hour average ozone peaked along the western shore of Galveston Bay, reaching 124 ppbv, almost 50 ppbv above the current EPA standard of 75 ppbv, at La Porte Sylvan Beach. Continental air pollution from the north and northeast was transported into the Houston metropolitan area where it mixed with locally generated emissions. A bay breeze circulation formed causing pollutants that were transported out over the water in the morning to recirculate back inland where they mixed with freshly emitted pollution near the bay breeze convergence zone. The highest surface ozone concentrations were reported near the bay breeze front at La Porte Sylvan Beach. This ozone episode will be presented using measurements made during the DISCOVER-AQ field campaign and WRF and CMAQ model simulations.

  7. 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…

  8. Surface Ozone in Kiev

    NASA Astrophysics Data System (ADS)

    Shavrina, A. V.; Mikulskaya, I. A.; Kiforenko, S. I.; Blum, O. B.; Sheminova, V. A.; Veles, A. A.

    The study of total ozone over Kiev and its concentration changes with height in the troposphere has been made on the base of ground-based observations with the infrared Fourier-spectrometer in the Main Astronomical Observatory of National Academy of Sciences of Ukraine (MAO NASU) as part of ESA-NIVR-KNMI project no 2907 "OMI validation by ground based remote sensing: ozone columns and atmospheric profiles "(2005-2008) [1,2,4]. Ground-level ozone in Kiev for an episode of its high concentrations in August 2000 was also simulated with the model of urban air pollution UAM-V [5,6]. In 2008 the satellite data Aura-OMI on profiles of ozone in the atmosphere OMO3PR became available (http://disc.sci.gsfc.nasa.gov/ Aura/data-holdings/OMI/ omo3pr_v003.shtml). They include ozone content in the lower layer of the atmosphere, beginning from 2005, which can be used to evaluate the ground-level ozone in all cities of Ukraine. The comparison of the data of ozone air pollution in Kiev (ozone - the pollutant of the first class of danger) and medical statistics data of of respiratory system (RS) diseases of the city population was carried out with the package "Statistica". A regression analysis, prognostic regression modelling, and retrospective prognosis of the epidemiological situation with respect to RS pathologies in Kiev in 2000-2006 were performed.

  9. 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.

  10. 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)

  11. 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.

  12. Diurnal variations of stratospheric ozone measured by ground-based microwave remote sensing at the Mauna Loa NDACC site: measurement validation and GEOSCCM model comparison

    NASA Astrophysics Data System (ADS)

    Parrish, A.; Boyd, I. S.; Nedoluha, G. E.; Bhartia, P. K.; Frith, S. M.; Kramarova, N. A.; Connor, B. J.; Bodeker, G. E.; Froidevaux, L.; Shiotani, M.; Sakazaki, T.

    2013-12-01

    There is presently renewed interest in diurnal variations of stratospheric and mesospheric ozone for the purpose of supporting homogenization of records of various ozone measurements that are limited by the technique employed to being made at certain times of day. We have made such measurements for 18 yr using a passive microwave remote sensing technique at the Mauna Loa Observatory in Hawaii, which is a primary station in the Network for Detection of Atmospheric Composition Change (NDACC). We have recently reprocessed these data with hourly time resolution to study diurnal variations. We inspected differences between pairs of the ozone spectra (e.g. day and night) from which the ozone profiles are derived to determine the extent to which they may be contaminated by diurnally varying systematic instrumental or measurement effects. These are small, and we have reduced them further by selecting data that meet certain criteria that we established. We have calculated differences between profiles measured at different times: morning-night, afternoon-night, and morning-afternoon and have intercompared these with like profiles derived from Aura-MLS, UARS-MLS, SMILES, and SBUV/2 measurements. Differences between averages of coincident profiles are typically <1.5% of typical nightime values over most of the covered altitude range with some exceptions. We calculated averages of ozone values for each hour from the Mauna Loa microwave data, and normalized these to the average for the first hour after midnight for comparison with corresponding values calculated with the Goddard Earth Observing System Chemistry Climate Model (GEOSCCM). We found that the measurements and model output mostly agree to better than 1.5% of the midnight value, with one noteworthy exception: the measured morning-night values are significantly (2-3%) higher than the modeled ones from 3.2 to 1.8 hPa (~39-43 km), and there is evidence that the measured values are increasing compared to the modeled values

  13. 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.

  14. The Re-Analysis of Ozone Profile Data from a 41-Year Series of SBUV Instruments

    NASA Technical Reports Server (NTRS)

    Kramarova, Natalya; Frith, Stacey; Bhartia, Pawan K.; McPeters, Richard; Labow, Gordon; Taylor, Steven; Fisher, Bradford

    2012-01-01

    In this study we present the validation of ozone profiles from a number of Solar Back Scattered Ultra Violet (SBUV) and SBUV/2 instruments that were recently reprocessed using an updated (Version 8.6) algorithm. The SBUV dataset provides the longest available record of global ozone profiles, spanning a 41-year period from 1970 to 2011 (except a 5-year gap in the 1970s) and includes ozone profile records obtained from the Nimbus-4 BUV and Nimbus-7 SBUV instruments, and a series of SBUV(/2) instruments launched on NOAA operational satellites (NOAA 09, 11, 14, 16, 17, 18, 19). Although modifications in instrument design were made in the evolution from the BUV instrument to the modern SBUV(/2) model, the basic principles of the measurement technique and retrieval algorithm remain the same. The long term SBUV data record allows us to create a consistent, calibrated dataset of ozone profiles that can be used for climate studies and trend analyses. In particular, we focus on estimating the various sources of error in the SBUV profile ozone retrievals using independent observations and analysis of the algorithm itself. For the first time we include in the metadata a quantitative estimate of the smoothing error, defined as the error due to profile variability that the SBUV observing system cannot inherently measure. The magnitude of the smoothing error varies with altitude, latitude, season and solar zenith angle. Between 10 and 1 hPa the smoothing errors for the SBUV monthly zonal mean retrievals are of the order of 1 %, but start to increase above and below this layer. The largest smoothing errors, as large as 15-20%, were detected in in the troposphere. The SBUV averaging kernels, provided with the ozone profiles in version 8.6, help to eliminate the smoothing effect when comparing the SBUV profiles with high vertical resolution measurements, and make it convenient to use the SBUV ozone profiles for data assimilation and model validation purposes. The smoothing error can

  15. Ozone in equatorial latitudes

    NASA Astrophysics Data System (ADS)

    Martini, L.; Zimmermann, G.; Trinkkeller, B.

    The presence of ozone in the atmosphere protects the biosphere against harmful solar UV radiation. The ozone distribution in the atmosphere is maintained on the basis of a complex system of reactions. The amount of atmospheric ozone might be reduced as a consequence of human activities. Such reduction in the atmospheric ozone could affect climate and biological processes on earth. As a part of plans for a further enhancement of the global surveillance of the atmospheric ozone layer, a series of radiation experiments concerning the quartz-ultraviolet region were conducted as a joint project of the German Democratic Republic and the USSR. The experiments had the objective to measure the radiative flux of the solar UV radiation and to determine absorption and dispersion of the radiation in the upper atmosphere. The investigation included the launching of 12 rockets from a research vessel in the Indian Ocean near the equator and 34 balloon flights.

  16. Errors in ozone risk assessment using standard conditions for converting ozone concentrations obtained by passive samplers in mountain regions.

    PubMed

    Gerosa, G; Finco, A; Marzuoli, R; Ferretti, M; Gottardini, E

    2012-05-01

    Passive samplers are often employed to measure ozone concentrations in remote areas such as mountain forests. The potential ozone risk for vegetation is then assessed by calculating the AOT40 exposure index (accumulated hourly ozone concentration exceedances above 40 ppb, i.e. AOT40 = Σ([O(3)] - 40)Δt for any hourly ozone concentration [O(3)] > 40 ppb). AOT40 is customary calculated on the basis of ozone concentrations expressed as a volumetric mixing ratio, while lab sheets normally report ozone concentrations from passive samplers in mass units per cubic metre. Concentrations are usually converted from mass units to ppb using a standard conversion factor taking SATP (Standard Ambient Temperature and Pressure) conditions into account. These conditions, however, can vary considerably with elevation. As a consequence, the blanket application of a standard conversion factor may lead to substantial errors in reporting and mapping ozone concentrations and therefore in assessing potential ozone risk in mountain regions. In this paper we carry out a sensitivity analysis of the effects of uncertainties in estimations of air temperature (T) and atmospheric pressure (P) on the concentration conversion factor, and present two examples from two monitoring and mapping exercises carried out in the Italian Alps. We derived P and T at each site from adiabatic lapse rates for temperature and pressure and analysed the magnitude of error in concentration estimations. Results show that the concentration conversion is much more sensitive to uncertainties in P gradient estimation than to air temperature errors. The concentration conversion factor (cf) deviates 5% from the standard transformation at an elevation of 500 m asl. As a consequence, the standard estimated AOT40 at this elevation is about 13% less than the actual value. AOT40 was found to be underestimated by an average between 25% and 34% at typical elevations of mountain forest stands in the Italian Alps when a correct

  17. Influence of future cropland expansion on regional and global tropospheric ozone

    NASA Astrophysics Data System (ADS)

    Squire, Oliver; Archibald, Alex; Telford, Paul; Pyle, John

    2013-04-01

    With the global population set to rise over the next 100 years, the fraction of land used for crop cultivation is likely to increase, the trend being most pronounced in developing regions such as Brazil and South East Asia. In these regions currently there stands natural rainforest, a high emitter of isoprene. As many staple crops, such as soy bean, are low emitters of isoprene, increasing the crop fraction in these regions will decrease isoprene emissions. Ozone over ~35 ppb has been shown to be damaging to plants, and as ground level ozone is sensitive to isoprene concentrations, altering isoprene emissions could increase ground level ozone, potentially resulting in crop damage. This mechanism was investigated by comparing two configurations of an atmospheric chemistry-climate model (UM-UKCA) under a 2100 climate following an IPCC scenario of moderate climate change. The first run had a present day crop distribution but isoprene emissions concurrent with 2100 temperatures and climatic conditions. The second run had isoprene emissions representative of both a 2100 climate and a 2100 crop distribution in accordance with the IMAGE model. By comparing these runs it was established that ozone increased by up to 8 ppb (~30%) due to crop land expansion. Over the Amazon (the most affected region) it was found that crops were exposed to a daily maximum 8-hour (DM8H) ozone above the 35 ppb threshold for up to 65 days more per year than in the base case. These conclusions suggest that increasing the crop fraction in current areas of natural rainforest could increase regional ground level ozone, having a significant effect on crop yield and air quality. The sensitivity of such conclusions to isoprene chemistry was examined by varying the isoprene chemistry scheme within the model. The CheT isoprene scheme used here (50 reactions) was compared with the AQUM (23 reactions) and CESM Superfast (2 reactions) isoprene schemes, all of which are currently used in Earth-system models

  18. Estimating contribution of wildland fires to ambient ozone levels in National Parks in the Sierra Nevada, California.

    PubMed

    Preisler, Haiganoush K; Zhong, Shiyuan Sharon; Esperanza, Annie; Brown, Timothy J; Bytnerowicz, Andrzej; Tarnay, Leland

    2010-03-01

    Data from four continuous ozone and weather monitoring sites operated by the National Park Service in Sierra Nevada, California, are used to develop an ozone forecasting model and to estimate the contribution of wildland fires on ambient ozone levels. The analyses of weather and ozone data pointed to the transport of ozone precursors from the Central Valley as an important source of pollution in these National Parks. Comparisons of forecasted and observed values demonstrated that accurate forecasts of next-day hourly ozone levels may be achieved by using a time series model with historic averages, expected local weather and modeled PM values as explanatory variables. Results on fire smoke influence indicated occurrence of significant increases in average ozone levels with increasing fire activity. The overall effect on diurnal ozone values, however, was small when compared with the amount of variability attributed to sources other than fire.

  19. Estimating contribution of wildland fires to ambient ozone levels in National Parks in the Sierra Nevada, California.

    PubMed

    Preisler, Haiganoush K; Zhong, Shiyuan Sharon; Esperanza, Annie; Brown, Timothy J; Bytnerowicz, Andrzej; Tarnay, Leland

    2010-03-01

    Data from four continuous ozone and weather monitoring sites operated by the National Park Service in Sierra Nevada, California, are used to develop an ozone forecasting model and to estimate the contribution of wildland fires on ambient ozone levels. The analyses of weather and ozone data pointed to the transport of ozone precursors from the Central Valley as an important source of pollution in these National Parks. Comparisons of forecasted and observed values demonstrated that accurate forecasts of next-day hourly ozone levels may be achieved by using a time series model with historic averages, expected local weather and modeled PM values as explanatory variables. Results on fire smoke influence indicated occurrence of significant increases in average ozone levels with increasing fire activity. The overall effect on diurnal ozone values, however, was small when compared with the amount of variability attributed to sources other than fire. PMID:19914752

  20. Interannual Variability in Baseline Ozone and Its Relationship to Surface Ozone in the Western U.S.

    PubMed

    Baylon, Pao M; Jaffe, Daniel A; Pierce, R Bradley; Gustin, Mae S

    2016-03-15

    Baseline ozone refers to observed concentrations of tropospheric ozone at sites that have a negligible influence from local emissions. The Mount Bachelor Observatory (MBO) was established in 2004 to examine baseline air masses as they arrive to North America from the west. In May 2012, we observed an O3 increase of 2.0-8.5 ppbv in monthly average maximum daily 8-hour average O3 mixing ratio (MDA8 O3) at MBO and numerous other sites in the western U.S. compared to previous years. This shift in the O3 distribution had an impact on the number of exceedance days. We also observed a good correlation between daily MDA8 variations at MBO and at downwind sites. This suggests that under specific meteorological conditions, synoptic variation in O3 at MBO can be observed at other surface sites in the western U.S. At MBO, the elevated O3 concentrations in May 2012 are associated with low CO values and low water vapor values, consistent with transport from the upper troposphere/lower stratosphere (UT/LS). Furthermore, the Real-time Air Quality Modeling System (RAQMS) analyses indicate that a large flux of O3 from the UT/LS in May 2012 contributed to the observed enhanced O3 across the western U.S. Our results suggest that a network of mountaintop observations, LiDAR and satellite observations of O3 could provide key data on daily and interannual variations in baseline O3. PMID:26882468

  1. 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.…

  2. 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 ...

  3. 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)

  4. Impact of Low-level Jet on Regional Ozone

    NASA Astrophysics Data System (ADS)

    Liu, F.

    2011-12-01

    During spring and summer seasons, the frequent occurrences of nocturnal low-level jet (LLJ) over Great Plains region of the United States are widely recognized. As an important element of the low-level atmospheric circulation this LLJ effectively transports water vapor from the Gulf of Mexico, which in turn affects the development of server weather over the central United States. The LLJ has long been known to be conducive to summer rainfall and widespread flooding over the Great Plains of North America. The LLJ transports more than just moisture. Ozone episodes occur mainly during summer and are influenced by regional transport. Little is known, however,about the interrelation between the Great Plains LLJ and regional ozone transport. In this study, analysis of observational data during 1993-2006 has shown strong influence of the Great Plains LLJ on local and regional ozone distributions. Hourly ozone measurements from Air Quality System (AQS) are compared with wind fields at 850 hPa from the NCEP North American Regional Reanalysis (NARR). It is demonstrated that the low ozone concentrations over Texas in late spring and summer are identified with large LLJ transport of clean marine air mass from the Gulf of Mexico. Significant negative correlations exist between daily ozone concentration and LLJ index (Figure 1), suggesting that lower ozone over Texas is associated with stronger LLJ. On the other hand, positive correlations occur in the Midwest and Northeast, indicating the important role of regional transport of ozone and precursors along the pathway by the wind circulation accompanying the LLJ. In addition, the LLJ is significantly correlated with northerly flows in the eastern Pacific Ocean and the adjacent coast. This relationship explains the coexistence of low ozone concentrations in Texas and southwestern U.S during summer, both attributed to the inland transport of clean marine air. These observed ozone-LLJ patterns are well simulated by the regional CMM5

  5. Spatial analysis of ozone in Atlanta: Regulatory and epidemiologic implications

    SciTech Connect

    Butler, A.J.; Mulholland, J.A.; Wilkinson, J.G.; Russell, A.G.; Tolbert, P.E.

    1998-12-31

    Relationships between ambient levels of selected air pollutants and pediatric asthma exacerbation in Atlanta were studied retrospectively. As a part of this study, spatial distributions of ambient ozone concentrations in the twenty-county Atlanta metropolitan area during the summers of 1993, 1994 and 1995 were estimated and assessed. A universal kriging procedure was used for spatial interpolation of aerometric monitoring station data. In this paper, the spatial distributions of ozone are described, and regulatory and epidemiologic implications are discussed. For the study period, the Atlanta ozone nonattainment area based on the one-hour, exceedance-based standard of 0.12 ppm is estimated to expand from 56 percent of the Atlanta MSA by area and 71 percent by population to 88 percent by area and 96 percent by population under the new eight-hour, concentration-based standard of 0.08 ppm. Regarding asthma exacerbation, a 4 percent increase in pediatric asthma emergency room presentation rate per 20 ppb increase in ambient ozone concentration was observed (p-value = 0.001). Ambient ozone level represents a general indicator of air quality due to its correlation with other pollutants. The use of spatially-resolved ozone estimates in the epidemiologic analysis demonstrates the need to control confounding by demographic covariates.

  6. Tropospheric Ozone and Biomass Burning

    NASA Technical Reports Server (NTRS)

    Chandra, Sushil; Ziemke, J. R.; Bhartia, P. K.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    This paper studies the significance of pyrogenic (e.g., biomass burning) emissions in the production of tropospheric ozone in the tropics associated with the forest and savanna fires in the African, South American, and Indonesian regions. Using aerosol index (Al) and tropospheric column ozone (TCO) time series from 1979 to 2000 derived from the Nimbus-7 and Earth Probe TOMS measurements, our study shows significant differences in the seasonal and spatial characteristics of pyrogenic emissions north and south of the equator in the African region and Brazil in South America. In general, they are not related to the seasonal and spatial characteristics of tropospheric ozone in these regions. In the Indonesian region, the most significant increase in TCO occurred during September and October 1997, following large-scale forest and savanna fires associated with the El Nino-induced dry season. However, the increase in TCO extended over most of the western Pacific well outside the burning region and was accompanied by a decrease in the eastern Pacific resembling a west-to-east dipole about the date-line. The net increase in TCO integrated over the tropical region between 15 deg N and 15 deg S was about 6-8 Tg (1 Tg = 10(exp 12) gm) over the mean climatological value of about 72 Tg. This increase is well within the range of interannual variability of TCO in the tropical region and does not necessarily suggest a photochemical source related to biomass burning. The interannual variability in TCO appears to be out of phase with the interannual variability of stratospheric column ozone (SCO). These variabilities seem to be manifestations of solar cycle and quasibiennial oscillations.

  7. Analysis of oxidative signalling induced by ozone in Arabidopsis thaliana.

    PubMed

    Mahalingam, Ramamurthy; Jambunathan, Niranjani; Gunjan, Samir Kumar; Faustin, Enock; Weng, Hua; Ayoubi, Patricia

    2006-07-01

    We are using acute ozone as an elicitor of endogenous reactive oxygen species (ROS) to understand oxidative signalling in Arabidopsis. Temporal patterns of ROS following a 6 h exposure to 300 nL L(-1) of ozone in ozone-sensitive Wassilewskija (Ws-0) ecotype showed a biphasic ROS burst with a smaller peak at 4 h and a larger peak at 16 h. This was accompanied by a nitric oxide (NO) burst that peaked at 9 h. An analysis of antioxidant levels showed that both ascorbate (AsA) and glutathione (GSH) were at their lowest levels, when ROS levels were high in ozone-stressed plants. Whole genome expression profiling analysis at 1, 4, 8, 12 and 24 h after initiation of ozone treatment identified 371 differentially expressed genes. Early induction of proteolysis and hormone-responsive genes indicated that an oxidative cell death pathway was triggered rapidly. Down-regulation of genes involved in carbon utilization, energy pathways and signalling suggested an inefficient defense response. Comparisons with other large-scale expression profiling studies indicated some overlap between genes induced by ethylene and ozone, and a significant overlap between genes repressed by ozone and methyl jasmonate treatment. Further, analysis of cis elements in the promoters of ozone-responsive genes also supports the view that phytohormones play a significant role in ozone-induced cell death. PMID:17080957

  8. Nimbus 7 solar backscatter ultraviolet (SBUV) ozone products user's guide

    NASA Technical Reports Server (NTRS)

    Fleig, Albert J.; Mcpeters, R. D.; Bhartia, P. K.; Schlesinger, Barry M.; Cebula, Richard P.; Klenk, K. F.; Taylor, Steven L.; Heath, Donald F.

    1990-01-01

    Three ozone tape products from the Solar Backscatter Ultraviolet (SBUV) experiment aboard Nimbus 7 were archived at the National Space Science Data Center. The experiment measures the fraction of incoming radiation backscattered by the Earth's atmosphere at 12 wavelengths. In-flight measurements were used to monitor changes in the instrument sensitivity. Total column ozone is derived by comparing the measurements with calculations of what would be measured for different total ozone amounts. The altitude distribution is retrieved using an optimum statistical technique for the inversion. The estimated initial error in the absolute scale for total ozone is 2 percent, with a 3 percent drift over 8 years. The profile error depends on latitude and height, smallest at 3 to 10 mbar; the drift increases with increasing altitude. Three tape products are described. The High Density SBUV (HDSBUV) tape contains the final derived products - the total ozone and the vertical ozone profile - as well as much detailed diagnostic information generated during the retrieval process. The Compressed Ozone (CPOZ) tape contains only that subset of HDSBUV information, including total ozone and ozone profiles, considered most useful for scientific studies. The Zonal Means Tape (ZMT) contains daily, weekly, monthly and quarterly averages of the derived quantities over 10 deg latitude zones.

  9. 29 CFR 778.421 - Offset hour for hour.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR STATEMENTS OF GENERAL... Regular Rate Principles Computing Overtime Pay on the Rate Applicable to the Type of Work Performed in... section 7(e)(5) or for work on “special days” (as under section 7(e)(6), or pursuant to an...

  10. Plant surface reactions: an ozone defence mechanism impacting atmospheric chemistry

    NASA Astrophysics Data System (ADS)

    Jud, W.; Fischer, L.; Canaval, E.; Wohlfahrt, G.; Tissier, A.; Hansel, A.

    2015-07-01

    Elevated tropospheric ozone concentrations are considered a toxic threat to plants, responsible for global crop losses with associated economic costs of several billion dollars per year. Plant injuries have been linked to the uptake of ozone through stomatal pores and oxidative damage of the internal leaf tissue. But a striking question remains: how much ozone effectively enters the plant through open stomata and how much is lost by chemical reactions at the plant surface? In this laboratory study we could show that semi-volatile organic compounds exuded by the glandular trichomes of different Nicotiana tabacum varieties are an efficient ozone sink at the plant surface. In our experiments, different diterpenoid compounds were responsible for a strongly variety dependent ozone uptake of plants under dark conditions, when stomatal pores are almost closed. Surface reactions of ozone were accompanied by prompt release of oxygenated volatile organic compounds, which could be linked to the corresponding precursor compounds: ozonolysis of cis-abienol (C20H34O) - a diterpenoid with two exocyclic double bonds - caused emissions of formaldehyde (HCHO) and methyl vinyl ketone (C4H6O). The ring-structured cembratrien-diols (C20H34O2) with three endocyclic double bonds need at least two ozonolysis steps to form volatile carbonyls such as 4-oxopentanal (C5H8O2), which we could observe in the gas phase, too. Fluid dynamic calculations were used to model ozone distribution in the diffusion limited leaf boundary layer under daylight conditions. In the case of an ozone-reactive leaf surface, ozone gradients in the vicinity of stomatal pores are changed in such a way, that ozone flux through the open stomata is strongly reduced. Our results show that unsaturated semi-volatile compounds at the plant surface should be considered as a source of oxygenated volatile organic compounds, impacting gas phase chemistry, as well as efficient ozone sink improving the ozone tolerance of plants.

  11. Removal of oxalic acid, oxamic acid and aniline by a combined photolysis and ozonation process.

    PubMed

    Orge, C A; Faria, J L; Pereira, M F R

    2015-01-01

    Aniline (ANL), an aromatic amine, oxalic acid (OXA) and oxamic acid (OMA), short-chain carboxylic acids, were chosen as model organic pollutants for testing the combined effect of neat photolysis and ozonation in the treatment of aqueous effluents. In order to better understand the results, single ozonation and neat photolysis were also carried out. OXA has a high refractory character relatively to single ozonation and neat photolysis only accounted for 26% conversion of OXA after 2 h of reaction. On the other hand, OXA complete degradation was observed in less than an hour when ozone and light were used simultaneously. Despite OMA, a compound never studied before by a combined ozonation and photolysis treatment, being highly refractory to oxidation, more than 50% was removed by photo-ozonation after 3 h of reaction. In the case of ANL, both single ozonation and photo-ozonation resulted in 100% removal in a short reaction period due to the high reactivity of ozone to attack this type of molecules; however, only the combined method leads to efficient mineralization (89%) after 3 h of reaction. A significant synergetic effect was observed in the degradation of the selected contaminants by the simultaneous use of ozone and light, since the mineralization rate of combined method is higher than the sum of the mineralization rates of the individual treatments. The promising results observed in the degradation of the selected contaminants are paving the way to the application of photo-ozonation in the treatment of wastewater containing this type of pollutants.

  12. Analysis of 2010-2014 Ground-Level Ozone at Trinidad Head, CA

    NASA Astrophysics Data System (ADS)

    Lennartson, E.; McClure-Begley, A.; Petropavlovskikh, I. V.; Leonard, M.

    2015-12-01

    High concentrations of ground-level ozone in the troposphere have negative impacts on human health and other biological organisms. As the US Environmental Protection Agency (EPA) is proposing to lower the National Ambient Air Quality Standard (NAAQS) for ozone from 75 to 65-70 parts per billion (ppb), it is important to further study the relationship between both anthropogenic and natural pollutants that lead to production and accumulation of surface ozone. Ground-level ozone data from Trinidad Head, California (THD) was analyzed from 2010-2014 to investigate the factors contributing to high ground-level ozone events. For this research project, a high ozone event was defined as ground-level ozone readings greater than the 90th percentile of the seasonal ozone variability observed during the 2003-2014 period. The ozone exceedances were also required to last for three continuous hours or more. Meteorological parameters, such as wind speed and synoptic patterns, were taken into account. In addition, impacts related to stratospheric intrusions, Asian pollution transport, and the influence of local forest fires were considered. We show that high ground-level ozone events at THD occur during a dominant wind direction and are highly dependent on the origin of the air mass. This understanding of enhanced ground-level ozone drivers will provide a foundational knowledge of climate adaptation and mitigation with improved scientific understanding of the changing climate and its impacts.

  13. Importance of NOx control for peak ozone reduction in the Pearl River Delta region

    NASA Astrophysics Data System (ADS)

    Li, Ying; Lau, Alexis K. H.; Fung, Jimmy C. H.; Zheng, Junyu; Liu, Shawchen

    2013-08-01

    As major air pollutants and key precursors of several secondary air pollutants, nitrogen oxide (NOx) emissions are regulated in many countries. However, NOx control increases ozone concentrations when the ozone formation regime is volatile organic compound (VOC) limited. Although many studies have shown that NOx regulation reduces ozone levels over the long term, it is still of concern that NOx regulation increases short-term ozone levels in metropolitan regions, where ozone formation is found to be predominantly VOC-limited. The Pearl River Delta (PRD) in China is such a region. Our modeling sensitivity study shows that while NOx reduction in the PRD region may raise the mean ozone concentration, it can also decrease peak ozone levels. Similar changes are observed in the NOx and ozone data of the PRD regional air quality monitoring network (2006-2012), lending further credence to our results. In the model, this NOx control effect is a result of the complicated spatial and diurnal variations of the ozone formation regime. In most of the PRD region, the formation regime is VOC-limited in the morning and becomes NOx-limited during peak ozone hours. Although some areas are always VOC-limited, their ozone concentrations are relatively low, and the ozone increases caused by NOx reduction generally do not cause higher ozone levels than the region's original ozone maxima. Several control scenarios are simulated to evaluate the effects of various possible control regulations. Our results show that in addition to VOC control, NOx control can be effective for reducing peak ozone concentrations in the PRD region.

  14. 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.

  15. 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

  16. 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. PMID:16627294

  17. 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

  18. 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.

  19. Record low ozone at the south pole in the Spring of 1993

    SciTech Connect

    Hofmann, D.J.; Oltmans, S.J.; Lathrop, J.A.; Harris, J.M.; Voemel, H. )

    1994-03-15

    On October 12, 1993, a balloon-borne ozone detector recorded a total ozone value of 91[+-]5 Dobson Units (DU) at the US Amundsen-Scott Station at the south pole. This is the lowest value of total ozone ever recorded anywhere, 13% below the previous low of 105 DU at the south pole in October of 1992. A region with a thickness of 5 km, from 14 to 19 km, was totally devoid of ozone as compared to only about half this thickness for the ozone void in 1992. Sub-100 DU total ozone values were observed on several soundings during 1993 whereas the 105 DU value was observed on only one occasion in 1992. The vertical profile of ozone indicates that the main reason for the record low ozone values in 1993 was an approximately 1 km upward extension of the ozone hole caused by unusual ozone loss in the 18-23 km region. Temperatures in this region were unusually low in September and October. Thus, the extension of the ozone hole may have been the result of the prolonged presence of polar stratospheric clouds at 18-23 km combined with the continued presence of sulfate aerosol from the Pinatubo eruption and, finally, increased chlorine levels. This scenario resulted in elevated ozone loss in a region where the ozone loss process is normally not saturated. 8 refs., 4 figs.

  20. Developing a predictive tropospheric ozone model for Tabriz

    NASA Astrophysics Data System (ADS)

    Khatibi, Rahman; Naghipour, Leila; Ghorbani, Mohammad A.; Smith, Michael S.; Karimi, Vahid; Farhoudi, Reza; Delafrouz, Hadi; Arvanaghi, Hadi

    2013-04-01

    Predictive ozone models are becoming indispensable tools by providing a capability for pollution alerts to serve people who are vulnerable to the risks. We have developed a tropospheric ozone prediction capability for Tabriz, Iran, by using the following five modeling strategies: three regression-type methods: Multiple Linear Regression (MLR), Artificial Neural Networks (ANNs), and Gene Expression Programming (GEP); and two auto-regression-type models: Nonlinear Local Prediction (NLP) to implement chaos theory and Auto-Regressive Integrated Moving Average (ARIMA) models. The regression-type modeling strategies explain the data in terms of: temperature, solar radiation, dew point temperature, and wind speed, by regressing present ozone values to their past values. The ozone time series are available at various time intervals, including hourly intervals, from August 2010 to March 2011. The results for MLR, ANN and GEP models are not overly good but those produced by NLP and ARIMA are promising for the establishing a forecasting capability.