| Autor: |
Dinkelacker, Brian T., Rivera, Pablo Garcia, Skyllakou, Ksakousti, Adams, Peter J., Pandis, Spyros N. |
| Zdroj: |
Atmospheric Chemistry & Physics Discussions; 9/19/2022, p1-30, 30p |
| Abstrakt: |
Biogenic secondary organic aerosol (bSOA) is a major component of atmospheric particulate matter (PM2.5) in the southeast United States especially during the summer, when emissions of biogenic volatile organic compound (VOCs) are high and emissions from anthropogenic sources enhance the formation of secondary particulate matter. We evaluate the performance of PM2.5 organic aerosol predictions by a chemical transport model (PMCAMx) in response to significant changes in anthropogenic emissions during the summers of 2001 and 2010. Average predicted bSOA concentrations in the southeast US did not change appreciably from the summer of 2001 to the summer of 2010, while the anthropogenic SOA decreased by 45 %. As a result, the biogenic fraction of total OA increased from 0.46 in 2001 to 0.63 in 2010. Partitioning effects due to reduced anthropogenic OA from 2001 resulted in 0.4 µg m-3 less biogenic OA on average in the southeast US in the summer of 2010. This was offset by biogenic SOA increases due to higher biogenic vapor emissions in the warmer 2010 summer. Little noticeable difference was observed in OA prediction performance in the southeast US between the two summer simulation periods. The fractional error of OA predictions remained practically the same (0.41 and 0.44 at CSN sites and 0.40 to 0.41 at IMPROVE sites in the summers of 2001 and 2010 respectively). The fractional bias of OA predictions increased from 0.10 to 0.22 at CSN sites and decreased from 0 to -0.09 at IMPROVE sites between the two periods. Removing the NOx-dependence of SOA formation yields resulted in higher fractional error and fractional bias at both CSN and IMPROVE sites in both summer periods, demonstrating the efficacy of the current formulation of SOA yields. Our analysis suggests that the changes in biogenic OA in this forested relatively polluted region appear to be dominated by the partitioning effects and the NOx effects on SOA yields. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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