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

During the summer of 2005, concentrations of surface ozone (O 3), oxides of nitrogen (NO x ), 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 O 3. The study deals with the characteristics of hourly and daily mean surface O 3 under different climatic conditions, such as temperature, relative humidity, wind speed and wind direction and other pollutant concentrations. The maximum hourly O 3 concentration reached 53 ppb on 17th May. The ground-level O 3 concentration in Chennai varied between 2 and 53 ppb. The concentration of NO x and O 3 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.