CHENNAI: There has been a significant spike in air pollution levels in Chennai. On Wednesday afternoon, the city’s air quality index (AQI) touched 240, which falls under ‘poor’ category as per National Ambient Air Quality Standards set by the Central Pollution Control Board, enough to cause breathing discomfort to most people on prolonged exposure.
Tamil Nadu Pollution Control Board (TNPCB) officials attributed the sudden jump in pollution levels to unfavourable meteorological conditions.
Chennai has seven continuous ambient air quality monitoring stations that provide real-time data on different air pollutants. Of the seven stations, the one at Alandur bus depot recorded AQI of 320 on Wednesday. The ‘very poor’ air quality level can cause respiratory illness to even healthy population on prolonged exposure. While four other stations recorded ‘poor’ air quality, two stations recorded ‘moderate’ levels. The dominant and most harmful pollutant, PM 2.5, peaked to 335 in some of the monitoring stations.
‘AQI up in Chennai due to unfavourable weather’
The concentration of harmful particulate matter is several times higher than the prescribed limit. The WHO prescribes 25 ug/m3 as the safe limit. India’s safe limit standard is 60 ug/m3.
PM 2.5 particles are 20 times smaller than the width of human hair. On breathing this air, the ultra-fine particles are quickly absorbed into the bloodstream, penetrating deep into the respiratory and circulatory systems. If the polluted air fills people’s lungs, it would affect the ability to breathe and will reduce life expectancy. Even short-term exposures to these particles can trigger symptoms of asthma and cause respiratory trouble or heart issues, experts say.
TNPCB chairman M Jayanthi told TNIE due to unfavourable weather conditions, there has been an increase in the value of AQI in Chennai and other coastal districts. IIT-Madras professor SM Shiva Nagendra, said, “Currently there is air inversion wherein the air cannot rise and pollution accumulates near the ground leading to higher pollutant concentration. Generally, air mass can travel 50 km and Chennai being blessed with coast, most of the pollutants travel into the sea. But now this movement or pollutant dispersal is restricted and pollutants are circulating and collecting in the same area.”