Particulate matter in Chennai air 4.5 times over safe levels prescribed by WHO, finds study

A recent study has found that Chennai’s air has particulate matter several times over the safe levels as stated by the updated World Health Organization (WHO) guidelines. 

A recent study has found that Chennai’s air has particulate matter several times over the safe levels as stated by the updated World Health Organization (WHO) guidelines. 

In a report by Greenpeace India titled ‘Spare the Air’, air quality of 11 major cities were analysed.

Particles in the air are defined by their diameter for quality regulatory purposes. Those with a diameter of 10 microns or less (PM10) are inhalable into the lungs and can induce adverse health effects. Fine particulate matter is defined as particles that are 2.5 microns or less in diameter (PM2.5). 

In 366 days between September 2021 and September 2022, the city averaged an annual PM10 concentration of 45.9 μg/m³, amounting to being 3.1 times the safe levels (15 μg/m³). The average annual nitrogen dioxide levels too were more than prescribed levels at 1.5 times over the WHO benchmark. 

However, the particulate matter level in cities such as Bengaluru, Hyderabad, Kolkata, Mumbai, and Lucknow is higher than that of Chennai. Long-term exposure to high levels of PM2.5 in air is known to cause health impacts.