Higher temperature can keep post-Diwali air pollution lower in Mumbai: SAFAR
With Mumbai recording the hottest day of this season so far on Saturday, the city is expected to witness marginally lower air pollution after Diwali due to changes in weather factors such as warmer conditions and increased wind speeds. said an official from the Air Quality System. Forecasting and Research (SAFAR).
The daytime temperature registered at the Santacruz meteorological observatory, representative of the city, was 36 degrees Celsius, 2.4 degrees Celsius above normal. Colaba, a representative from South Mumbai, registered 35 degrees Celsius, almost 2 degrees Celsius above normal.
Pollution levels were in the “moderate” air quality category on Saturday (Diwali) against a “poor” air quality prediction. The Air Quality Index (AQI) for all pollutants on Saturday was 111 (moderate) with PM2.5 levels in the satisfactory category of 54 micrograms per cubic meter (µg / m3) against the safe limit of 60 µg / m3. , and AQI for PM2.5 to 98 (satisfactory).
SAFAR released a revised air quality forecast for Sunday that read: “One positive development is that the prevailing temperature is not as cold as expected. Also the increase in wind speed may bring relief for Mumbai and the AQI will be towards the lower end of the very poor category with a 50% firecracker scenario (half of the average firecracker emissions in 2016-2018). In the event that no firecracker emissions occur, the AQI is likely to remain stable and only within the poor range. “
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The most polluted areas are expected to be Chembur, Mazgaon and Malad on Sunday. On Saturday, not a single place in Mumbai registered ‘poor’ or ‘very poor’ air. Bhandup and Navi Mumbai had the cleanest air.
“The highest levels of PM10 and PM2.5 are expected between 1 am and 4 am between Saturday night and Sunday morning. Air quality will begin to improve as of Monday, ”SAFAR said.
Compared to the originally predicted AQI of 338 (very poor), which would have been the worst post-Diwali air quality in six years, SAFAR’s revised forcecast said the AQI was expected to be 309 (very poor) on Sunday and 267 (poor) with 50% cracker emissions, and 227 (poor) on Sunday and 203 (poor) on Monday with zero firecracker emissions. SAFAR classifies AQI levels from 0 to 50 as good, 51 to 100 satisfactory, 101 to 200 as moderate, 201 to 300 is poor, 301 to 400 is very poor, and above 401 it is severe.
Gufran Beig, project director, SAFAR said: “When the temperature and wind speed are low, the polluting particles are suspended closer to the surface, but in this case, current climatic factors may allow a slight increase in dispersion. of polluting particles “.
According to the Indian Meteorological Department (IMD), the wind direction changed from cooler northeast winds to warmer easterly winds to southeast winds on Saturday, allowing temperatures to rise. The wind speed ranged between 11 and 14 km / hour compared to the average wind speed for the last three days at 5-6 km / hour. Saturday’s low temperature rose to 22 degrees Celsius (one degree Celsius above normal) from 19.6 degrees Celsius on Friday in the suburbs, while southern Mumbai saw a 1 degree Celsius rise from Friday to 24 degrees Celsius on Saturday.
SAFAR also predicted that the PM2.5 concentration on Sunday would be more than double the safe limit if firecrackers were used. Against the safe limit of 60 µg / m3, Mumbai could register 132 µg / m3 on Sunday (50% firecracker emissions) and 98 µg / m3 (zero firecracker emissions).