Surface ozone variability in the southern most semi-urban area, Nagercoil, India

Ozone is an important atmospheric constituent due to its role both as a green house gas and an oxidant. Interactions between ozone and climate naturally occur not only in the stratosphere, but also at the earth´s surface (troposphere). This study aspires to access the amount of surface ozone concentration in and around Nagercoil ( 8°11´ N, 77°29´ E ). A portable Aeroqual series 200 Ozone monitor has been used for measuring purposes. Sampling was carried out at two sites influenced by same meteorological conditions during four seasons in the period of 2007-2008. The measurements showed a well marked diurnal cycle of surface ozone concentration which clearly follows the diurnal variation of surface temperature. Results of this study have revealed that the annual mean of daily average surface ozone concentration was 19.19 ± 3.21 ppb .The highest average seasonal concentration was determined in summer and lowest in north east monsoon for both the sites. A difference of 2.73 ppb was observed in the annual mean of daily average surface ozone concentration between the two sites. Statistical t-test in this study shows that this difference is only due to the difference in the levels of VOC and precursor gas emissions.