Air quality worsens after 9 ‘satisfactory’ days

Gurugram Air quality in the city dipped considerably on Wednesday, entering the ‘moderate’ category of the Central Pollution Control Board’s (CPCB) air quality index (AQI) after nine consecutive days of being in the ‘satisfactory’ category (with a daily average AQI value of less than 100).

On Wednesday, Gurugram’s AQI score stood at 112, worsening from a reading of 72 the previous day. The concentration of PM2.5 stood at an average of 111ug/m3, up from 24ug/m3 on Tuesday. Experts said this was due to high-speed winds, which were raising locally present dust particles.

“There has also been a marked absence of rainfall over the past two days, due to which the pollutants remained suspended in air,” a scientist with the CPCB’s air quality lab in Delhi said. From July 16 to July 23, the city consistently recorded ‘satisfactory’ air quality thanks to the onset of the monsoon, resulting in precipitation of pollutants.

“Relative humidity levels have also been high, making particles heavier and causing them to remain close to the ground,” the scientist said.

However, with the India Meteorological Department (IMD) predicting a spate of heavy rains beginning July 25, air quality is expected to improve again. According to the Central Control Room for Air Quality Management in Delhi, the predicted daily AQI for Gurugram is 74 on Thursday, 66 on Friday and 78 on Saturday, indicating favourable air quality days ahead.

On Wednesday, the day temperature remained at 37.3 degrees Celsius — three degrees above the normal temperature for this time of the year. The IMD recorded a relative humidity of 80% at 5pm. According to scientists, the high humidity levels are a result of easterly winds blowing over the region. The minimum temperature on Wednesday was 28.5 degrees Celsius, which increased by one unit from Tuesday.

Towards the evening, the sky turned cloudy and winds of 20kmph speed, as recorded at the IMD’s Palam observatory, hit the region. However, no rain was reported.

An intense spell of rain is expected to lash the city on Thursday, the IMD said. The shower, which is likely to continue till at least Friday, is expected to be the heaviest of the season so far, experts said. Due to the widespread rain over the next two to three days, the maximum and minimum temperatures are expected to fall by three to four degrees Celsius.

First Published:
Jul 24, 2019 21:08 IST

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