Rain clears Delhi air of dangerous pollutants

Delhi reported a steep fall in the levels of dangerous pollutants in its air, most notably the ultrafine PM1 particles, after the recent rain.

Delhi reported a steep fall in the levels of dangerous pollutants in its air, most notably the ultrafine PM1 particles, after the recent rain.

Gufran Beig, A leading atmospheric scientist, told Hindustan Times that according to readings at Lodhi Road, PM2.5 and PM1 levels had gone down dramatically in the month of July.

“From an average 45.2 microgram per cubic metre in the month of June, the PM10 level has decreased to 20.4 microgram per cubic metre in July. In April, it was 24.33 and in May it had gone up to 42.55. The sudden drop in July might be because of the monsoon showers,” Beig, the project director of the country’s first ever System of Air Quality Weather Forecasting and Research (SAFAR), said.

The July figure is an average till Tuesday, according to data collected at Lodhi Road by SAFAR, which is developed by Pune-based Indian Institute of Tropical Meteorology (IITM) -- an autonomous body under the ministry of earth sciences.

“On most days, the proportion of PM1 is about 35% of the PM2.5 emissions but on days it gets more than 50% of PM2.5. These become worrying figures as they reflect the fact that people are breathing in ultrafine particles that have serious health impacts,” Beig said.

Even PM2.5 levels have come down post-showers in July. In April the figure was 77.95 microgram per cubic metre, and in May it went up to 132.34 microgram per cubic metre while in June it was 130.4. However, in July it came down to 54.2 microgram per cubic metre.