The average daily concentration of finer particulate matter with a diameter less than 2.5 micrometres (PM2.5), the city’s most prominent pollutant, on Thursday, was 362ug/m3, touching a maximum of 398ug/m3. Private air quality monitors also recorded ‘very poor’ air quality, with daily AQIs ranging between 325 and 347 at 8.30pm, after a spate of light showers and strong winds.
Thanks to the rain, the air quality is expected “to improve further on 13.12.2019 and reach in poor to moderate category. The air quality is likely to remain in the lower end of poor category on 14.12.2019,” as per the ministry of earth sciences early air quality warning system for Delhi-NCR.
“The predominant surface wind is likely to be from the southeast direction of Delhi, with wind speed up to 12 kilometres per hour (kmph) on 13.12.2019 generally cloudy sky, light rain/thundershowers accompanied with hail storm and strong surface wind(speed 25-30Kmph) during the day,” the bulletin stated.
The predicted daily average AQI value for Gurugram on Friday, according to the CPCB’s central control room in Delhi, is 163 (in the ‘moderate’ category of the AQI). On Saturday, it is expected to improve further to 145, before falling off sharply again on Sunday, to re-enter the ‘very poor’ category, with an expected index value of 309.
Air quality is expected to deteriorate significantly after Sunday, when daytime temperatures will start plummeting. “This will bring down wind speeds and bring the particles to a lower mixing height, meaning they will settle closer to the ground, between 500 and 1,200 metres above the earth’s surface,” a senior scientist at the CPCB’s air quality lab in Delhi said.
Prasanta Patnaik