Isoprene and its oxidation products, methyl vinyl ketone and methacrolein, in the rural troposphere

Journal Article · Wed Jan 20 04:00:00 EST 1993 · Journal of Geophysical Research; (United States)

DOI:https://doi.org/10.1029/92JD02382· OSTI ID:6830430

Montzka, S A; Goldan, P D; Kuster, W C; Fehsenfeld, F C ^[1]; Trainer, M ^[2]

---

1. National Oceanic and Atmospheric Administration, Boulder, CO (United States)
2. National Oceanic and Atmospheric Administration, Boulder, CO (United States) Univ. of Colorado, Boulder (United States)

The mixing ratios of methyl vinyl ketone (CH[sub 2]=CHCOCH[sub 3]) and methacrolein (CH[sub 2]=C(CH[sub 3])COH) were measured at a site located in the Kinterbish Wildlife Management Area in western Alabama. The measurements were made between June 15 and July 20, 1990. Considering all the data over the whole measurement period, the concentrations of these two carbonyls were approximately equal at this isolated rural site. The average mixing ratios for methyl vinyl ketone and methacrolein were 0.98 parts per billion by volume (ppbv) and 0.66 ppbv, respectively, while the medians were 0.87 ppbv and 0.57 ppbv. The methyl vinyl ketone mixing ratio varied from 3.4 ppbv to the detection limit of the instrument, =0.01 ppbv, while the methacrolein mixing ratio varied from 2.6 ppbv to 0.027 ppbv. These carbonyls constituted a significant fraction of the volatile organic compounds observed at the site: theft mixing ratios, measured 2 m above the top of the forest canopy, were less than that of the dominant compound isoprene but were considerably greater than the mixing ratios of anthropogenic compounds (e.g., benzene). The mixing ratios of methyl vinyl ketone and methacrolein were found to be highly correlated and exhibited a systematic variation with respect to each other. On average, during the day, methyl vinyl ketone was larger than methacrolein, while methacrolein tended to be slightly larger during the night. The systematic behavior of these compounds with respect to each other and other compounds measured at the site were simulated using a one-dimensional photochemical model. These observations were consistent with the production and loss of isoprene, methyl vinyl ketone, and methacrolein by photochemical oxidation reactions. 39 refs., 11 figs., 2 tabs.

• OSTI ID: 6830430
• Journal Information: Journal of Geophysical Research; (United States), Journal Name: Journal of Geophysical Research; (United States) Vol. 98:D1; ISSN JGREA2; ISSN 0148-0227
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400500 -- Photochemistry
54 ENVIRONMENTAL SCIENCES
540120* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
ALABAMA
ALDEHYDES
CHEMICAL REACTIONS
DEVELOPED COUNTRIES
DIENES
EARTH ATMOSPHERE
ECOLOGICAL CONCENTRATION
HYDROCARBONS
ISOPRENE
KETONES
MIXING RATIO
NORTH AMERICA
ORGANIC COMPOUNDS
OXIDATION
PHOTOCHEMICAL REACTIONS
POLYENES
TROPOSPHERE
USA