Visibility-reducing organic aerosols in the vicinity of Grand Canyon Nationl Park: 1. Properties observed by high resolution gas chromatography

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:166532

Mazurek, M A ^[1]; Mason-Jones, M; Mason-Jones, H ^[2]

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1. Brookhaven National Lab., Upton, NY (United States)
2. California Institute of Technology, Pasadena, CA (United States)

During the summer of 1989, an air monitoring program was established within the Grand Canyon and on the South Rim to define summertime organic aerosol concentration and composition as a function of elevation in the canyon. Supporting information was collected on the composition of the inorganic portion of the atmospheric aerosol to help place the relative importance of organics in perspective. The present paper describes the ambient air monitoring experiment, quantifies the bulk chemical composition of the fine (dp< 2.1=135m) and total aerosol components, distinguishes carbonaceous aerosols according to their organic carbon, elemental carbon and carbonate content, and then examines those characteristics of the organic aerosol that can be defined via capillary gas chromatography using flame ionization detection (GC-FID). At both Indian Gardens (in-canyon, IG) and at Hopi Point (South Rim, HP), the largest contributors to the fine aerosol consist of sulfate and associated ammonium ion plus aerosol carbon species. At IG, sulfate and ammonium ion account for 25.5% and 7.5% of the fine aerosol, respectively, nearly equaled by the 29.9% of the sample composed of organic compounds and 1% contributed by elemental carbon. Somewhat more than half of the fine aerosol at HP can be explained by sulfate ion, ammonium ion, organic compounds and elemental carbon, again with roughly equal mass concentrations due to the ionic versus carbonaceous components. Monthly average mass concentrations for fine aerosol organics were 1.1 = B5gm -3(IG) and 1.3 =135gm-3 (HP), while the total organics monthly average mass concentrations were 1.9 =135gm-3 (IG) and 2.1 =135gm-3 (HP). The fraction of aerosol organics that could be evaluated by GC-FID (elutable organics) constituted 27% to 53% of the total organics mass collected as fine or total aerosol. For the fine particle monthly composites, the elutable organics were present in mass concentrations of 0.28 =B5gm-3 (IG) and 0.46 =135gm-3 (HP).

• OSTI ID: 166532
• Report Number(s): CONF-9510126--
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
AEROSOL MONITORING
AEROSOLS
CHEMICAL COMPOSITION
COMPLEX TERRAIN
ECOLOGICAL CONCENTRATION
GAS CHROMATOGRAPHY
LEVELS
ORGANIC COMPOUNDS
QUANTITATIVE CHEMICAL ANALYSIS