‘DUST STORM FROM WEST ASIA MAIN TRIGGER FOR DELHI SMOG’

As Delhi and its neighbours spar over stubble burning, a Centre-run monitoring agency has identified a West Asian dust storm as the chief trigger behind the recent smog episode in the region.

On November 8, the contribution of the dust storm was 40%, eclipsing the role of emissions from stubble burning, which stood at 25%, the Pune-based System of Air Quality And Weather Forecasting And Research (SAFAR) said.

That was the day pollution levels peaked with PM2.5 concentration reaching 640 micrograms per cubic metre (ug/m3), according to the SAFAR scientific assessment report of the week-long pollution crisis accessed by PTI.

“Rest was made up of emissions from local sources such as vehicular combustion. If external sources did not have any role, levels of PM2.5 during this period could have been around 200 µg/ m3,” the report stated.

The subsequent imposition of emergency measures such as a ban on the entry of trucks and construction activities yielded positive results, the agency said, putting the gains at around 15%.

PM2.5 are ultrafine particulates, up to 30 times finer than a width of a human hair, which can lodge deep in the lungs and enter the bloodstream, causing irreparable harm to living beings.

The 24-hour prescribed standard of this variety of suspended particulate matter is 60 ug/m3.

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