Air quality ‘poor’ as winds change direction

After a three-day run of ‘moderate’ air quality, pollution levels in the city rose to settle in the ‘poor’ category of the Air Quality Index (AQI), with 231 on the

After a three-day run of ‘moderate’ air quality, pollution levels in the city rose to settle in the ‘poor’ category of the Air Quality Index (AQI), with 231 on the Central Pollution Control Board’s (CPCB) daily AQI bulletin. This was up from up the previous day’s 184 (moderate). The daily average concentration of PM2.5, Gurugram’s most prominent pollutant, stood at 237µg/m³, up from Monday’s 175µg/m³.

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Experts and officials attributed the deterioration primarily to a change in wind speed. “Winds on Tuesday were blowing from the southeast direction of Delhi-NCR, whereas they have largely been blowing from the west the past few days. This would have caused some short-range transportation of dust toward the west, affecting air quality in Gurugram,” a senior scientist with the CPCB’s air quality lab in Delhi said.

According to the early air quality warning system for Delhi-NCR, however, “Predominant surface wind is likely to be coming from northwest direction of Delhi having wind speed up to 16 kmph on 05.02.2020 with mainly clear sky, mist/shallow fog in the morning and strong surface winds (15-20 kmph) during the day (sic).” With this, some of Gurugram’s pollution load will once again be transferred toward the western parts of Delhi-NCR, the CPCB scientist explained.

The minimum temperature on Tuesday fell marginally—to 5.3 degrees Celsius from Monday’s 5.4 degrees Celsius—according to data with the India Meteorological Department (IMD). Minimum temperatures since Saturday have been around two to three degrees below the normal temperature for this time of the year. The minimum temperature on Wednesday could rise by a degree, an IMD spokesperson said.

The maximum temperature, meanwhile, fell to 20.8 degrees Celsius from 21.3 degrees Celsius the previous day, as per the IMD. The maximum temperature, however, is expected to rise further to 22-23 degrees Celsius around Friday, which will be accompanied by strong surface winds, which are predicted after Wednesday. Shallow to moderate fog is expected early mornings till at least Sunday, as per the IMD.