CHENNAI : The people of Chennai no doubt contributed to the low pollution levels in the city, but experts believe weather too had played a role. Besides some experts remained sceptical about the data released by the Tamil Nadu Pollution Control Board (TNPCB) on Wednesday. Some even felt the weather had a big role to bring the pollution levels down — both PM10 and PM2.5.
IIT-Madras professor SM Shiva Nagendra said weather played an important role in keeping a check on pollution. “Sunlight, clear skies and wind play an important role in dispersing the pollutants. This year, things have fallen perfectly. Besides, Chennai is also gifted with sea breeze being a coastal district. Last year, the city suffered primarily because of unfavorable climatic conditions. With cloudy skies, no rain and wind, all the pollutants stayed low,” he said.
No doubt the use of fire crackers has come down and people are slowly changing. But, Chennai recording an all-time low pollution levels was not expected. In 2015, even when Chennai witnessed unprecedented rainfall and fire crackers sales was crippled, the air pollution was much higher than this year.
The PM10 reading this year in Triplicane is 70 µg/m3 (micrograms per cubic metre), Besant Nagar 75 µg/m3, Nungambakkam 48 µg/m3 , Sowcarpet 114 µg/m3 and T Nagar 97 µg/m3. When compared to 2015, which is said to be the lowest polluted year, PM10 recording in Triplicane was 90 µg/m3, while in Besant Nagar it was 88 µg/m3, Sowcarpet 93 µg/m3, Nungambakkam 131 µg/m3 and T Nagar 126 µg/m3.
Interestingly, TNPCB data show there is not much difference between the pollution levels recorded on Monday (day before) and Tuesday (Deepavali day). In fact, PM2.5 levels have dropped in Triplicane and Nungambakkam on Deepavali day. City-based environmentalist Shweta Narayan said the TNPCB data is also silent on day’s peak measurements.
“The Central Pollution Control Board (CPCB) real-time monitoring stations at Alandur, Manali and IIT-Madras show that PM2.5 levels have peaked as high as 302 µg/m3 in Alandur, 230 µg/m3 in Manali and 160 µg/m3 in IIT-Madras. Air Quality Index (AQI) on Deepavali day for Chennai was 103, while the standard is 60. Our air quality monitor in Ennore measured PM2.5 peak level of 916 µg/m3 between 5 pm and 7 pm on Tuesday,” she said. When contacted, a senior TNPCB official said: “Although weather played its part, there is a definite improvement on the ground and our data is completely reliable.”