Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You or Your Team.

Learn More →

Effect of aqueous-phase processing on aerosol chemistry and size distributions in Fresno, California, during wintertime

Effect of aqueous-phase processing on aerosol chemistry and size distributions in Fresno,... Environmental context Aqueous-phase processes in fogs and clouds can significantly alter atmospheric fine particles with consequences for climate and human health. We studied the influence of fog and rain on atmospheric aerosol properties, and show that aqueous-phase reactions contribute to the production of secondary aerosol species and change significantly the composition and microphysical properties of aerosols. In contrast, rains effectively remove aerosols and reduce their concentrations. Abstract Submicrometre aerosols (PM 1 ) were characterised in situ with a high resolution time-of-flight aerosol mass spectrometer and a scanning mobility particle sizer in Fresno, CA, from 9 to 23 January 2010. Three dense fog events occurred during the first week of the campaign whereas the last week was influenced by frequent rain events. We thus studied the effects of aqueous-phase processing on aerosol properties by examining the temporal variations of submicrometre aerosol composition and size distributions. Rains removed secondary species effectively, leading to low loadings of PM 1 dominated by primary organic species. Fog episodes, however, increased the concentrations of secondary aerosol species (sulfate, nitrate, ammonium and oxygenated organic aerosol). The size distributions of these secondary species, which always showed a droplet mode peaking at ~500 nm in the vacuum aerodynamic diameter, increased in mode size during fog episodes as well. In addition, the oxygen-to-carbon ratio of oxygenated organic species increased in foggy days, indicating that fog processing likely enhances the production of secondary organic aerosol as well as its oxidation degree. Overall, our observations show that aqueous-phase processes significantly affect submicrometre aerosol chemistry and microphysics in the Central Valley of California during winter, responsible for the production of secondary inorganic and organic aerosol species and the formation of droplet mode particles, thus altering the climatic and health effects of ambient aerosols in this region. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Environmental Chemistry CSIRO Publishing

Effect of aqueous-phase processing on aerosol chemistry and size distributions in Fresno, California, during wintertime

Loading next page...
 
/lp/csiro-publishing/effect-of-aqueous-phase-processing-on-aerosol-chemistry-and-size-sWh1WmmyxK

References (93)

Publisher
CSIRO Publishing
Copyright
CSIRO
ISSN
1448-2517
eISSN
1449-8979
DOI
10.1071/EN11168
Publisher site
See Article on Publisher Site

Abstract

Environmental context Aqueous-phase processes in fogs and clouds can significantly alter atmospheric fine particles with consequences for climate and human health. We studied the influence of fog and rain on atmospheric aerosol properties, and show that aqueous-phase reactions contribute to the production of secondary aerosol species and change significantly the composition and microphysical properties of aerosols. In contrast, rains effectively remove aerosols and reduce their concentrations. Abstract Submicrometre aerosols (PM 1 ) were characterised in situ with a high resolution time-of-flight aerosol mass spectrometer and a scanning mobility particle sizer in Fresno, CA, from 9 to 23 January 2010. Three dense fog events occurred during the first week of the campaign whereas the last week was influenced by frequent rain events. We thus studied the effects of aqueous-phase processing on aerosol properties by examining the temporal variations of submicrometre aerosol composition and size distributions. Rains removed secondary species effectively, leading to low loadings of PM 1 dominated by primary organic species. Fog episodes, however, increased the concentrations of secondary aerosol species (sulfate, nitrate, ammonium and oxygenated organic aerosol). The size distributions of these secondary species, which always showed a droplet mode peaking at ~500 nm in the vacuum aerodynamic diameter, increased in mode size during fog episodes as well. In addition, the oxygen-to-carbon ratio of oxygenated organic species increased in foggy days, indicating that fog processing likely enhances the production of secondary organic aerosol as well as its oxidation degree. Overall, our observations show that aqueous-phase processes significantly affect submicrometre aerosol chemistry and microphysics in the Central Valley of California during winter, responsible for the production of secondary inorganic and organic aerosol species and the formation of droplet mode particles, thus altering the climatic and health effects of ambient aerosols in this region.

Journal

Environmental ChemistryCSIRO Publishing

Published: Jun 26, 2012

Keywords: Aerodyne high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS), aqueous-phase reaction, fog/cloud processing, SOA production, submicrometre aerosol chemistry.

There are no references for this article.