RETROSPECTIVE ANALYSIS OF A THEORETICAL MODEL USED FOR FORECASTING FUTURE AIR QUALITY NEAR THE NORTH CHENNAI THERMAL POWER PLANT

The trend of gathering of Baseline Air Quality data commenced in Chennai as early as 1981, as an academic exercise, undertaken by some post-graduate students of the Centre for Environmental Studies in Anna University, Chennai (1,2,3,4). The study revealed that the baseline air quality data were only at moderate levels, in respect of the three major air pollutants, namely, Sulphur Dioxide (SO2), Nitrogen Dioxide (NO2), and Suspended Particulate Matter (SPM), in Ennore-Manali Industrial area. All these pollutants measured for the respective averaging times, were below the National Ambient Air Quality Standards prescribed for each pollutant, respectively. Therefore, it was possible to convince the Department of Environment & Forests, Government of India, New Delhi, that the Environmental Clearance be given, for the proposed establishment of the 3x210 MW coal-fired thermal power plant in the Ennore Island location, with the financial assistance from the Asian Development Bank to the Tamil Nadu Electricity Board. The present status of air quality in the same area needs to be assessed in the light of the Revised National Ambient Air Quality Standards, especially in view of the newly introduced parameters, namely, PM10 and PM2.5, which were not in force in the year 1986. There are a few more industries which have come up after 1986, and which have relevance to emission of air pollutants , namely, SO2, NO2, and SPM (inclusive of PM10 and PM2.5), having adverse effects on human health.