Air quality remains poor
Air quality in the city remained in the poor category of the Central Pollution Control Board’s air quality index (AQI) on Sunday, for the first time in a week, with a reading of 296 on the daily pollution bulletin. This is up from a reading of 256 (also poor) the day prior. As per official forecasts, pollution levels are expected to remain in the upper end of the poor to the lower end of the very poor AQI category for the next five days.
The average level of ultrafine particulate matter having a diameter of 2.5 microns or less (PM 2.5), the city’s primary pollutant, was 204 micrograms per cubic metre (µg/m³) on Sunday, as per the CPCB’s air quality monitor at Vikas Sadan in Sector 11. At the official monitor in Sector 51, the PM 2.5 concentration stood at 350µg/m3. Both the readings were beyond the permissible limit of 60µg/m³.
Kuldeep Srivastava, head of India Meteorological Department’s (IMD) regional forecasting centre, said that pollution levels will continue to improve over the next week, with rising temperatures expected to lead to higher wind speeds and increasing the mixing height of pollutants — 0which refers to the vertical height at which suspended particles mix with the air.
“The wind speed is expected to touch about 15 kilometres per hour, and increasing temperatures will cause upward movement of air and increase the ventilation index, which indicates the rate of dispersal,” said Shrivastava.
As per the early air quality warning system for Delhi-NCR, the ventilation index is likely to increase from approximately 9000 m²/s on 22.02.2021 to 10,000 m²/s on 23.02.2021. A ventilation index of 6,000 m²/s or more is necessary for the effective dispersal of pollutants.
While the IMD’s automatic weather station (AWS) for Gurugram did not record the minimum temperature on Sunday, the IMD’s AWS at the Palam observatory in Delhi recorded the day’s minimum temperature at 11.8 degrees Celsius and the maximum temperature at 26 degrees Celsius.
As per the IMD’s weekly forecast, the maximum and minimum temperatures are expected to hover around 29 and 14 degrees Celsius, respectively, over the next few days. Shallow to moderate episodes of fog will continue during the morning, despite being an atypical weather phenomenon for this time of the year.