CHENNAI: Do Chennaiites know what they are breathing? While the TNPCB claims the pollution levels stayed within limits on the day of Deepavali, the continuous ambient air quality monitoring stations of the Central Pollution Control Board (CPCB) have a different story to tell. The primary pollutant PM2.5, a tiny particulate matter of diameter 2.5 or less than 2.5 microns that can enter deep into the lungs, spiked as high as 430 in the Velachery area, which is more than seven times the prescribed limits.
The TNPCB, which usually measures air pollution at five places in Chennai to monitor the impact of the Deepavali celebrations, said on Monday that there was no significant increase in the values of PM10, PM2.5, SO2 and NO2 in the city. Levels of PM2.5 in Besant Nagar, T Nagar, Nungambakkam and Triplicane were within 60 µg/m3 (micrograms per cubic metre) limit and only Sowcarpet recorded marginally higher levels of 62 µg/m3.
But, this stands in stark contrast to what the CPCB monitors placed in Velachery, Alandur, Manali and Manali depict. All four stations have recorded poor Air Quality Index (AQI) on Sunday and even till Monday afternoon.
Velachery has recorded poor AQI of about 250 (24 hours average) for most part of Sunday and Monday. During peak firecrackers bursting hours, it went up to 436. As per the National Air Quality Index, AQI between 401 and 500 is considered as severe, which affects healthy people and seriously impacts those with existing diseases. Anything between 201 and 300 is considered poor causing breathing discomfort to people.
In Alandur, it was as high as 500. Same was the case with Manali station. At 9 pm on Sunday, all stations recorded AQI of about 250. A senior TNPCB official told Express that the CPCB monitors work real-time and take an average of every 15 minutes. “Pollution levels are determined by road condition, vehicular traffic, industrial emissions etc. There would be fluctuations, but our data shows there has been no significant increase. The weather also played its part. The clear skies on the Deepavali day have helped pollution disperse faster.”
In a release, the pollution board has said, “The considerable reduction of pollution level was mainly due to public co-operation in complying with the Supreme Court directions and the awareness created by the TNPCB with co-operation of the other government departments and media.”
Though the TNPCB data kept pollution levels under limit, the noise levels were relatively higher indicating that the use of firecrackers has reduced greatly. All five monitoring stations recorded the noise level ranging from 67 to 84 dB(A) on Sunday while the limit is 45 to 65 dB(A) depending on area classification. City-based environmentalist Shweta Narayan said: “Whom should we believe, TNPCB or CPCB? There can’t be so much of discrepancy in data.”