Formation of gas-phase peroxides in a rural atmosphere: An interpretation of the recent SOS/SERON field results

Conference · Wed Sep 01 04:00:00 EDT 1993

OSTI ID:10104615

Lee, J H; Tang, I N ^[1]; Weinstein-Lloyd, J B ^[2]

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1. Brookhaven National Lab., Upton, NY (United States)
2. State Univ. of New York, Old Westbury, NY (United States). Chemistry/Physics Dept.

Hydrogen perioxide (H{sub 2}O{sub 2}) and certain organic peroxides such as hydroxymethyl-hydroperoxide (HMHP), are gas-phase oxidants present in the atmosphere at ppbv concentration levels. These oxidants play an important role in atmospheric chemistry. In addition, precipitation containing H{sub 2}O{sub 2} is toxic to trees, and it has also been suggested that organic peroxides formed presumably by ozone reactions with biogenic alkenes are responsible for leaf disorders. Recently, we have developed a nonenzymatic method or aqueous-phase H{sub 2}O{sub 2} measurement, using Fenton reagent and fluorescent hydroxy- benzoic acid. The new method, in conjunction with the well-known method of p-hydroxyphenylacetic acid and horseradish peroxidase for total peroxides, and together with an improved gas scrubber to mitigate sampling line problems, has been successfully deployed in recent SOS/SERON field measurements in rural Georgia. For the first time, continuously measured and speciated gas-phase peroxide data have become available, making it possible to examine some aspects of the ozone chemistry leading to the formation of these oxidants. It is observed that daily H{sub 2}O{sub 2} maximum frequently occurs at a different time than does HMHP, and that H{sub 2}O{sub 2} concentration, but not HMHP, tends to correlate with solar fluxes measured at the same location. These findings seem to indicate that the formation mechanisms for H{sub 2}O{sub 2} and organic peroxides are basically different. It is likely that H{sub 2}O{sub 2} is formed from radical-radical recombination, while HMHP is formed by ozone-alkene reactions. Since the gas-phase ozone-alkene reactions are usually too slow to account for the diurnal concentration variations observed for HMHP, heterogeneous processes involving ozone and alkenes are also a possibility.

• Research Organization: Brookhaven National Lab., Upton, NY (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States); National Science Foundation, Washington, DC (United States)
• DOE Contract Number: AC02-76CH00016; FG02-91ER61206
• OSTI ID: 10104615
• Report Number(s): BNL--49600; CONF-940115--12; ON: DE94002995; BR: KP0201000; CNN: Grant ATM-9112698
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540110
ALKYLATION
ATMOSPHERIC CHEMISTRY
BASIC STUDIES
FLUORESCENCE SPECTROSCOPY
GEORGIA
HYDROGEN PEROXIDE
ORGANIC OXYGEN COMPOUNDS
OXIDIZERS
PEROXIDES
PHOTOCHEMICAL REACTIONS
RADICALS
SOLAR FLUX