Observations of nonmethane hydrocarbons and oxygenated volatile organic compounds at a rural site in the southeastern United States

Journal Article · Sun Nov 01 04:00:00 EST 1998 · Journal of Geophysical Research

DOI:https://doi.org/10.1029/98JD02677· OSTI ID:678837

Riemer, Daniel; Pos, Willer; Milne, Peter; Farmer, Charlesk; Shepson, Paul; Starn, Tim

Measurements of an extensive range of nonmethane hydrocarbons (NMHCs) including alkanes, alkenes, and aromatics, and oxygenated volatile organic compounds (OVOCs) including alcohols, ketones, and aldehydes were conducted for several weeks during the summer of 1995 as part of the Southern Oxidants Study (SOS) at a rural experimental site (Youth, Inc.) 32 km southeast of Nashville, Tennessee, in the southeastern United States. These measurements were conducted to (1) determine the absolute magnitude and variability of oxygenated compounds found in a contemporary rural region; (2) assess the importance of the measured ambient levels of OVOCs on a photochemical reactivity basis relative to the more commonly determined NMHCs; and (3) to evaluate our ability to accurately measure oxygenates by the current techniques employed under a field study scenario. Several other physical (temperature, insolation, etc.), meteorological (wind velocity, wind direction, atmospheric structure, and boundary layer height), and chemical (criterion pollutants, NO{sub x}, SO{sub 2}, CO, O{sub 3}, etc.) parameters were measured concurrently with the NMHC and OVOC measurements. During the study period, OVOCs were consistently the dominant compounds present, and methanol and acetone had the highest mixing ratios. Although OVOCs made up the majority of the volatile organic compound component on a mass basis, a substantial sink for OH was isoprene and its immediate oxidation products, methacrolein and methyl vinyl ketone. In combination with CO and formaldehyde, these compounds comprised about 85{percent} of the observed OH reactivity at the site. Acetaldehyde and methanol were responsible for an additional 10{percent}, with the NMHCs and remaining OVOCs making up the final 5{percent} of the measured OH reactivity at the site. These observed patterns reinforce recent studies which find OVOCs to be an important component of the rural troposphere. {copyright} 1998 American Geophysical Union

• OSTI ID: 678837
• Journal Information: Journal of Geophysical Research, Journal Name: Journal of Geophysical Research Journal Issue: D21 Vol. 103; ISSN JGREA2; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
AIR POLLUTION MONITORING
ATMOSPHERIC CHEMISTRY
CHEMICAL ANALYSIS
MEASURING METHODS
ORGANIC COMPOUNDS
OZONE
PHOTOCHEMICAL REACTIONS
PHOTOCHEMISTRY
RURAL AREAS
TROPOSPHERE