Air quality monitoring in Chennai, India, in the summer of 2005

During the summer of 2005, concentrations of surface ozone (O3), oxides of nitrogen (NOx), respirrable suspended particulate matter (RSPM) and total suspended particulate matter (TSPM), relative humidity (RH), wind speed (WS) and wind direction (WD) were collected over successive periods of about 24 h at five sites. UV photometric ozone analyzer was used to measure the concentration of surface O3. The study deals with the characteristics of hourly and daily mean surface O3 under different climatic conditions, such as temperature, relative humidity, wind speed and wind direction and other pollutant concentrations. The maximum hourly O3 concentration reached 53 ppb on 17th May. The ground-level O3 concentration in Chennai varied between 2 and 53 ppb. The concentration of NOx and O3 were below the prescribed limits. The TSPM values were exceeded the National Ambient Air Quality Standards (NAAQS) at Koyambedu, Mandaveli, Taramani and Vallalar Nagar study area.