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Air quality at two-month high, mercury to rise

By HT Correspondent
PUBLISHED ON JAN 31, 2020 08:55 PM IST

Air quality in the city improved on Friday, with a reading of 87 (‘satisfactory’) on the Central Pollution Control Board’s (CPCB) air quality index (AQI) daily bulletin. This was down from 119 (‘moderate’) the previous day and marked only the second day in two months that the city recorded an AQI score below 100. On January 24, Gurugram had recorded an AQI of 92.

Experts and officials attributed Friday’s improvement to high-speed north and north-westerly winds, of up to 15kmph, which blew over Delhi-NCR on Friday, and increase in the maximum temperature. Manesar, which lies upwind from Gurugram, also recorded ‘satisfactory’ air on Friday, with an AQI of 92.

The minimum temperature on Friday dropped to 7.2 degrees Celsius, from 8 degrees Celsius the previous day, according to the India Meteorological Department (IMD). The maximum temperature, meanwhile, increased from 17.1 degrees Celsius on Thursday to 18.1 degree Celsius on Friday.

As per an IMD forecast, the minimum and maximum temperatures are set to 10 and 21 degrees Celsius, respectively, by February 6.

Delhi, Faridabad, Noida and Greater Noida, meanwhile, recorded ‘moderate’ air, while Ghaziabad recorded ‘poor’ air quality on Friday. “Gurugram is benefitting from prevailing meteorology, with winds carrying pollutants over short and medium ranges toward Delhi and beyond,” a senior scientist with the CPCB’s air quality lab in Delhi said.

Additionally, fast winds are also triggered by an increase in maximum daytime temperature. “This helps not only in lateral dispersion of pollutants, but also horizontal, as rising temperatures cause pollutants to settle at higher mixing heights,” the CPCB scientist explained.

On Friday, the mixing height of pollutants over Delhi-NCR remained at 1000 metres above the earth’s surface and is expected to settle at 2000 metres on Saturday.

According to the early air quality warning system for Delhi-NCR, “The air quality is likely to deteriorate marginally but remain in moderate to poor category on 01.02.2020. The air quality is likely improve marginally and remain in moderate category on 02.02.2020.” A CPCB forecast on Friday predicted that the average daily AQI for Gurugram would range between 167 on Saturday to 182 on Monday.

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