Air quality after Diwali tied to level of fireworks

Delhi’s air quality is likely to worsen and turn ‘severe’ a day after Diwali, mainly due to meteorological conditions that will trap pollutants from local sources such as firecrackers.

This time, the atmospheric conditions are such that the after Diwali air quality is entirely tied to the level of firecrackers the city witnesses on the night of the festivities, experts said on Tuesday.

With an air quality index (AQI) of 306, the city’s air quality was recorded as ‘very poor’ by the Central Pollution Control Board (CPCB) on Tuesday and the possibility of it turning ‘severe’ is looming large.

However, in Rajasthan’s Bhiwadi, which is an industrial hub barely 80 kilometres from Delhi and part of the National Capital Region, AQI was severe, the worst in the entire country.

“The level of moisture in the air will shoot up on October 20. Speed of local wind movement, which plays a crucial role in dispersing pollutants, will also be low thus resulting in accumulation of pollutants,” CPCB member secretary A Sudhakar said.

Sunita Narain, a member of the Supreme Court-empowered Environment Pollution Prevention and Control Authority, said the toxicity of the pollutants, including road or construction dust, increases manifold when coated with chemicals, which are present in firecrackers, and warned against measuring pollution merely going the volume of dust in air.

The 24-hour rolling average of PM 2.5, which are ultrafine pollutants 30 times finer than the width of a human hair, was 137 micrograms per cubic metre (ug/m3) on Tuesday, violating the safe standard of 60 by over two times.

Winter is a critical time in Delhi as meteorological conditions trap air pollutants near the earth’s surface.