Special Trend of surface ozone observed at industrial site, in Chennai

Abstract

In this study, the trend of surface ozone (O3) concentration was observed by continuous monitoring in the Industrial and coastal site Chennai, India during the period 07th October 2005 to 18th January 2006. The relationships between the ambient concentrations of O3 with oxides of nitrogen (NOx), carbon monoxide (CO), temperature, wind speed and relative humidity were also observed simultaneously. The diurnal variation profile experienced in November - January is rather typical for an area not influenced by local sources. No remarkable change in O3 concentrations was observed at night except in the month of October. The monthly average maximum O3 concentration was 44.3 ppb recorded during nighttime in the month of January 2006. This may be due to the high ozone in the night at Ennore due to advection of ozone from near by high ozone concentration site. The effect of meteorological parameters particularly on temperature is observed.