The air quality in Chennai has deteriorated to alarming levels. An hourly data feed from Central Pollution Control Board’s app – Sameer – shows that as of Nov 7th, 2:37 PM, the Air Quality Index (AQI) level in Velachery area stood at 271 (as compared to Delhi which is at 282 at the same time). The Weather Channel AQI data for the same time showed Chennai AQI as 217.
While the calculation to arrive at AQI may differ, but one thing is clear from the findings across all these reports. The air is not healthy for breathing. Chennai’s natural air conditioner – the sea breeze – has not been very active. This stillness is not helping the situation either.
What’s spoiling our air?
Particulate Matter (PM) is a mixture of solid and liquid particles that are suspended in the air. PM 2.5 is an atmospheric particulate matter with a diameter of less than 2.5 micrometres, which is around 3 per cent of the diameter of a human hair. PM 2.5 particles, which cause respiratory problems and reduce visibility, can only be detected with the help of an electron microscope because they are so small.
Exposure to PM2.5 has multiple short and long term health consequences. Short term includes irritation in the eyes, nose and throat, coughing, sneezing and shortness of breath. Prolonged exposure to PM2.5 can cause chronic health problems such as asthma, chronic bronchitis and heart disease. According to the World Health Organisation, the ideal levels of PM2.5 in the air is 25 ug/m3 (annual average). As per the Central Pollution Board, the acceptable levels of PM2.5 in the ambient air in India must be limited to 50 ug/m3. The PM2.5 particle count in Velachery area on Nov 7 stood at 105.7 ug/m3
On June 5 2019, the Government of India launched the National Clean Air Program (NCAP) which proposes to chalk out national-level strategy for reducing the levels of air pollution at both the regional and urban level. The target is for reduction of 20-30% of PM2.5 and PM10 concentration by 2024. As part of this programme, a list of 102 cities has been identified to protect public health and spread awareness on the adverse impact of outdoor air pollution. This list was prepared by studying air quality data levels based on National Ambient Air Quality Standards (NAAQs) between 2011 and 2015.
Surprisingly Tuticorin is the only city from Tamil Nadu which made it to this list. There is no mention of Chennai. The photos below, however, clearly show the haze of pollution in different areas of our city at various times of the day:
It now seems that the only saviour for Chennai could be Cyclone Bulbul, which is expected to hit the eastern coast of India by next week. This is likely to blow the polluted air away. Till then people with asthma, children, older adults and outdoor workers should reduce prolonged outdoor exposure.