Warm weather cleanses city’s surface-level air in Gurugram

Officials from the Haryana State Pollution Control Board (HSPCB) and India Meteorological Department (IMD) attributed improvement in the air quality to favourable meteorological conditions, such as increased temperature and wind speed.

Air quality in the city improved on Thursday, putting Gurugram’s air back in the ‘poor’ category after two days of ‘very poor’ air, with a daily Air Quality Index (AQI) value of 236. This was down from 345 on Wednesday.

Thick layer of smog hung over Gurugram’s Sector 67 on Thursday morning. Air cleared up as the day progressed. (Parveen Kumar/HT Photo)

The concentration of PM2.5 around the city’s primary air quality monitor at Vikas Sadan dropped from 323ug/m3 on Wednesday to 244ug/m3 on Thursday. In Gwal Pahari, where a second air quality monitor is active, PM2.5 level dropped from 490ug/m3 Wednesday to 207ug/m3, according to data available via the Central Pollution Control Board’s (CPCB) National Air Quality Index web app.

Officials from the Haryana State Pollution Control Board (HSPCB) and India Meteorological Department (IMD) attributed improvement in the air quality to favourable meteorological conditions, such as increased temperature and wind speed.

According to the data provided by the IMD, maximum daytime temperature increased from 29° Celsius the previous day to 29.9° Celsius on Thursday, which in turn triggered an increase in wind speed.

“Higher temperatures usually result in higher wind speed, and that is what has helped to clear the air today,” said Kuldeep Singh, regional officer (Gurugram), HSPCB.

“If the effect of temperature rise is felt for a prolonged period of time, across many hours, it can substantially increase wind speeds and change the mixing height of aerosols and reduce the level of pollution closer to the ground,” said a former member of the CPCB’s air quality lab.

Singh added that the opening of the Kundli-Manesar-Palwal (KMP) Expressway on Monday might have had a mitigating effect on pollution levels in Gurugram.

“The effects of this will be seen in coming months,” he said, explaining that the newly opened highway would help in steering bypassable traffic away from the city, especially high-emission diesel trucks.

Gurugram remained the least polluted city in Delhi-NCR for the 15th consecutive day on Thursday. However, improvement in air quality were felt across the region, with Delhi, Noida, Faridabad and Ghaziabad also entering the ‘poor’ category as opposed to being in the ‘very poor’ on Wednesday owing to similar weather conditions.

Temperature rise... across many hours, it can substantially increase wind speeds and change the mixing height of aerosols and reduce pollution closer to ground.