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Factors controlling the photochemical generation of gaseous H 2 O 2 in the Los Angeles atmosphere
Author(s) -
Sakugawa Hiroshi,
Tsai Wangteng,
Kaplan Isaac R.,
Cohen Yoram
Publication year - 1990
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl017i001p00093
Subject(s) - atmosphere (unit) , troposphere , limiting , atmospheric sciences , sulfuric acid , environmental science , photochemistry , meteorology , chemistry , physics , inorganic chemistry , mechanical engineering , engineering
The factors for controlling the photochemical generation of gaseous H 2 O 2 were studied on the basis of both field data and model predictions. Field data of the concentration of gaseous H 2 O 2 at ground‐level were obtained in west Los Angeles during 1985–88. The results indicate that there is a clear seasonal trend of gaseous H 2 O 2 (0.03–1.35 ppb, n=150) with highest concentrations in the summer. Statistical analyses revealed that the concentration of H 2 O 2 increases with increasing solar radiation at a statistically significant level. A one‐dimensional photochemical model, which is based on the prevailing meteorological conditions and primary pollutants loading in Los Angeles, also predicted that solar radiation is the major factor in determining the formation rate of H 2 O 2 in the atmosphere. These results indicate that solar radiation significantly controls the formation of gaseous H 2 O 2 . Considering the low photochemical activity in the winter, H 2 O 2 is probably limiting for the oxidation of SO 2 in the Los Angeles winter atmosphere where the SO 2 content exceeds the H 2 O 2 concentrations. Our results also imply that, if the UV radiation in the troposphere increases due to the depletion of the stratospheric O 3 content, the H 2 O 2 levels will increase and as a result the production of sulfuric acid will increase in the winter atmosphere.