Air quality impact and physicochemical aging of biomass burning aerosols during the 2007 San Diego wildfires

TitleAir quality impact and physicochemical aging of biomass burning aerosols during the 2007 San Diego wildfires
Publication TypeJournal Article
Year of Publication2013
AuthorsZauscher M.D, Wang Y., Moore M.JK, Gaston C.J, Prather KA
JournalEnvironmental Science & Technology
Volume47
Pagination7633-7643
Date Published2013/07
Type of ArticleArticle
ISBN Number0013-936X
Accession NumberWOS:000322059800010
Keywordsaerosols; atmospheric; chemical-characterization; flight mass-spectrometry; gas-chromatography; individual particles; matter; mixing state; organic-compounds; particulate; positive matrix factorization; source apportionment
Abstract

Intense wildfires burning >360000 acres in San Diego during October 2007 provided a unique opportunity to study the impact of wildfires on local air quality and biomass burning aerosol (BBA) aging. The size-resolved mixing state of individual particles was measured in real-time with an aerosol time-of-flight mass spectrometer (ATOFMS) for 10 days after the fires commenced. Particle concentrations were high county-wide due to the wildfires; 84% of 120-400 nm particles by number were identified as BBA, with particles <400 nm contributing to mass concentrations dangerous to public health, up to 148 mu g/m(3). Evidence of potassium salts heterogeneously reacting with inorganic acids was observed with continuous high temporal resolution for the first time. Ten distinct chemical types shown as BBA factors were identified through positive matrix factorization coupled to single particle analysis, including particles comprised of potassium chloride and organic nitrogen during the beginning of the wildfires, ammonium nitrate and amines after an increase of relative humidity, and sulfate dominated when the air mass back trajectories passed through the Los Angeles port region. Understanding BBA aging processes and quantifying the size-resolved mass and number concentrations are important in determining the overall impact of wildfires on air quality, health, and climate.

DOI10.1021/es4004137
Short TitleEnviron. Sci. Technol.
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