HR: 18:05h
AN: A44A-07    [Abstracts]
TI: What is the influence from biomass burning and/or climate change on changing ozone in the western US?
AU: * Jaffe, D
EM: djaffe@u.washington.edu
AF: University of Washington, 18115 Campus Way NE, Bothell, WA 98011, United States
AU: Hafner, W
EM: whafner@uwb.edu
AF: University of Washington, 18115 Campus Way NE, Bothell, WA 98011, United States
AU: Westerling, T
EM: awesterling@ucmerced.edu
AF: University of California Merced, PO Box 2039, Merced, CA 95344, United States
AB: In a recent study (Jaffe and Ray, 2007), we identified a broad and statistically significant pattern of increasing daytime O3 at 7 of 9 rural sites in the western U.S. These sites show an average O3 increase of 0.3 ppbv/year in O3 over the past ~18 years. Surprisingly, this increase is present in all seasons. In this study we explore whether climate change (changes in temperature) and/or increasing biomass burning play a role in changing ozone across the this region. To do this we examined variations in O3 and PM2.5 at numerous rural sites in the western U.S. that are part of the IMPROVE and/or CASTNET monitoring programs. Using a fire database that was developed from state and federal fire reports (Westerling et al., 2006), we find good correlations between area burned and PM2.5 and O3 concentrations at most sites. In some cases, we also found a correlation between air quality in one region and area burned another region, indicating transport of smoke and other emissions from the fires. During large fire years, summertime mean PM2.5 and O3 are enhanced by 4-5 ug/m3 and 6-7 ppbv, respectively. There is also a significant correlation between fires and temperature. Thus a changing fire regime may be responsible for increasing O3 in the western US during summer and can have a significant influence on our ability to meet air quality objectives.
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0365 Troposphere: composition and chemistry
DE: 0368 Troposphere: constituent transport and chemistry
SC: Atmospheric Sciences [A]
MN: 2007 Joint Assembly