Water-Soluble Organic Matter in Atmospheric Fine Particles..

Research studies on wood smoke and other air pollution.

Water-Soluble Organic Matter in Atmospheric Fine Particles..

Postby Wilberforce » Wed May 04, 2011 7:59 pm

Characterization and Source Apportionment of Water-Soluble Organic Matter in Atmospheric Fine Particles (PM2.5) with High-Resolution Aerosol Mass Spectrometry and GC–MS
Yele Sun†, Qi Zhang†*, Mei Zheng‡§, Xiang Ding‡, Eric S. Edgerton, and Xinming Wang



Water-soluble organic matter (WSOM) in fine particles (PM2.5) collected at one rural and three urban sites from the Southeastern Aerosol Research and Characterization network were characterized with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR–ToF–AMS). These samples were also analyzed for a suite of molecular markers by Gas Chromatography–Mass Spectrometry (GC-MS) to assist in the interpretation of WSOM sources. The HR–ToF–AMS measurements allow a direct determination of the organic mass-to-carbon ratios (average ±1σ = 1.93 ± 0.12) and hence the quantification of WSOM on the same filters used to close the aerosol mass budget. WSOM constitutes a major fraction of total PM2.5 mass (26–42%) and organic mass (50–90%) at all sites. The concentrations of WSOM are substantially higher in summer, mainly due to enhanced production of biogenic secondary organic aerosol (SOA). WSOM is composed mainly of oxygenated species with average oxygen-to-carbon (O/C) ratio of 0.56 (±0.08). Positive matrix factorization (PMF) of the high resolution mass spectra of WSOM identifies a less oxidized component (denoted as lOOA, O/C = 0.50) associated with biogenic SOA and a more oxidized component (denoted as mOOA, O/C = 0.60) associated with WSOM contributed by wood combustion. On average, lOOA accounts for 75 (±13) % of WSOM in summer while mOOA accounts for 78 (±21) % in winter, suggesting that WSOM in the southeastern U.S. is primarily contributed by SOA production from biogenic species in summer and by wood burning emissions in winter. This work also demonstrates the utility of HR–ToF–AMS for investigating the bulk chemical composition of WSOM as well as for evaluating its source contributions.
• The Surgeon General has determined that there is no safe level of exposure to ambient smoke!

• If you smell even a subtle odor of smoke, you are being exposed to poisonous and carcinogenic chemical compounds!

• Even a brief exposure to smoke raises blood pressure, (no matter what your state of health) and can cause blood clotting, stroke, or heart attack in vulnerable people. Even children experience elevated blood pressure when exposed to smoke!

• Since smoke drastically weakens the lungs' immune system, avoiding smoke is one of the best ways to prevent colds, flu, bronchitis, or risk of an even more serious respiratory illness, such as pneumonia or tuberculosis! Does your child have the flu? Chances are they have been exposed to ambient smoke!
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