Capital’s air quality improves, may get fouler from Sunday

In the morning, the 24-hour rolling average of PM10 and PM2.5 were 318 and 175 microgram per cubic metre, respectively. Acceptable levels are 60 and 100 microgram per cubic metre, respectively.

Air quality in the Capital was “very poor” on Friday, better than Thursday, when pollution reached severe levels in some part of the city. However, things will worsen again from Sunday, say pollution forecasts.

According to SAFAR advisory, people with existing heart or lung diseases, senior citizens, and children must avoid exertion when the air quality is ‘very poor’. (Arvind Yadav/ HT File)

The overall Air Quality Index read 342, which is “very poor”, but better than Thursday’s 369.

As per System of Air Quality Weather Forecasting and Research (SAFAR) advisory, people with existing heart or lung diseases, senior citizens, and children must avoid exertion when the air quality is “very poor”.

In the morning, the 24-hour rolling average of PM10 and PM2.5 touched very poor limits, according to SAFAR data. PM 10 was recorded at 318 and PM 2.5 at 175 microgram per cubic metre.

PM2.5 and PM10 are ultrafine particles that are the dominant pollutants in Delhi. The 24-hour acceptable levels of PM 2.5 and PM10 are 60 and 100 microgram per cubic metre, respectively.

Friday’s levels were slightly better than Thursday’s 334 and 183 readings. “Things have become slightly better compared to past 2-3 days. It started to get better since Thursday afternoon as the surface wind speed increased,” Gufran Beig, programme director of SAFAR, told HT.

However, Beig said these “better” days won’t last long. “The situation will remain same on Friday and Saturday. From Sunday, however, it is likely to be more polluted. This is because of cold waves in the entire North belt, upper wind towards Delhi region and calm lower winds,” he said.

The main factors that influence Delhi’s air quality are wind speed and direction. Whenever the surface wind speed decreases, pollution levels shoot up.