1. Ozone Update Ben Wells U.S. Environmental Protection Agency Office of Air Quality Planning and Standards Air Quality Analysis Group February 11, 2014

2. Overview Past: Ozone data through 2012 – 2012 ozone trends and design values – Influence of meteorology Present: Preliminary 2013 data – Preview of 2013 ozone data – Public data access tools Future: 2013 design values and trends updates 2

3. Ozone Trend, 2000 - 2012 The national average of the annual 4 th highest concentrations: – Decreased by 9% from 2000 to 2012 – Decreased by 21% from 2002 to 2009 – Increased by 8% from 2009 to 2012 90 th Percentile 50 th Percentile 10 th Percentile 3

4. Change in 8-hour Ozone Design Values 2009-2011 to 2010-2012 4 Average increase of 2.0 ppb

5. Influence of Meteorology on Ozone 5 Ozone tends to be highest on hot, dry days with calm or light winds Meteorological conditions are more favorable toward ozone formation in some years than in others EPA uses a statistical model to “adjust” seasonal average ozone trends to remove effects due to meteorological variability

6. Influence of Meteorology on Ozone 6 (< 60 ppb) (60 – 75 ppb) (76 – 95 ppb) (96 – 115 ppb) (> 115 ppb)

7. Meteorology: 2012 vs. 2013 Source: National Climatic Data Center (http://www.ncdc.noaa.gov/)http://www.ncdc.noaa.gov/ 7 Temperature Precipitation April – September 2012April – September 2013 ← Cooler Average Warmer → ← Drier Average Wetter →

8. 8 Average decrease of 5.2 ppb Change in May - September Mean 8-hour Ozone Values, 2012 to 2013 (2013 values based on preliminary data)

9. 9 Change in Annual 4 th Highest 8-hour Ozone Values, 2012 to 2013 (2013 values based on preliminary data) Average decrease of 7.2 ppb

10. AirData: http://www.epa.gov/airdata/http://www.epa.gov/airdata/ – Download daily air quality concentration data or annual summary statistics for any monitor or geographic area – Several visualization tools for generating downloadable graphics based on air quality concentration data – Provides the latest data available in EPA’s AQS database AirTrends: http://www.epa.gov/airtrends/http://www.epa.gov/airtrends/ – View or download trends in EPA’s six criteria pollutants, nationally, regionally, and locally – Download official design values for EPA’s six criteria pollutants – Updated annually by AQAG (August) 10 Public Data Access Tools

11. 2013 Design Values and Trends Updates May 1, 2014 – Deadline for 2013 air quality data certification in AQS May – AQAG retrieves data from AQS and generates draft 2013 design value tables June – EPA regional office review of draft design values Late June/early July – AQAG retrieves data from AQS for final design values and trends July/August – AQAG generates final 2013 design value tables and updates trends information August 2014 – AQAG updates the AirTrends webpage 11

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