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Surface ozone scenario at Pune and Delhi during the decade of 1990s

Ali, K and Inamdar, SR and Beig, G and Ghude, S and Peshin, S (2012) Surface ozone scenario at Pune and Delhi during the decade of 1990s. Journal of Earth System Science, 121 (2). pp. 373-383.

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Data on surface ozone concentration compiled for a 10-year period from 1990 to 1999 for Pune and Delhi are analyzed in terms of its frequency distribution, annual trend, diurnal variation and its relation with various meteorological and chemical parameters. It is found that the surface ozone concentration range showing highest frequency of occurrence at Pune is 0-5 ppb during winter and post-monsoon seasons and 15-20 ppb and 5-10 ppb during summer and monsoon seasons, respectively. It is 0-5 ppb at Delhi during all the seasons. The surface ozone concentration has shown a decreasing trend at Pune during the observational period with an average rate of decrease of 1.54 ppb/year. On the other hand, there is no trend whatsoever in the variation of surface ozone concentration at Delhi. Minimum value of surface ozone occurs before sunrise and maximum in the afternoon hours. Regression analyses of surface ozone with maximum temperature (r = 0.46 for Pune and 0.51 for Delhi, significant at more than 0.1) and NO 2 at respective locations indicate that surface ozone at these locations is mainly produced by photochemistry. Transport mechanism is also understood to have contributed significantly to the total concentration of ozone. Inverse relationship obtained between surface ozone concentration and relative humidity indicates that major photochemical paths for removal of ozone become effective when humidity increases at these locations.

Item Type: Article
Additional Information: Copyright of this article belongs to Indian Academy of Sciences.
Uncontrolled Keywords: annual variation; atmospheric chemistry; concentration (composition); diurnal variation; monsoon; observational method; ozone; photochemistry; relative humidity; trend analysis; winter, Delhi; India; Maharashtra; Pune
Subjects: Meteorology and Climatology
Depositing User: IITM Library
Date Deposited: 21 Dec 2013 07:36
Last Modified: 21 Dec 2013 07:36

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