Mumbai air will be the cleanest since 2015 this Diwali: SAFAR
Mumbai is also expected to have air that is cleaner than Delhi, Pune and Ahmedabad, other cities where SAFAR monitors pollution levelsmumbai Updated: Oct 18, 2017 00:37 IST
This Diwali, you can expect pollution levels to be the lowest since 2015. Reason: High wind speed and widespread rain in and around Mumbai will disperse pollutants from the air, researchers with the System of Air Quality Forecasting and Research (SAFAR) said.
Mumbai is also expected to have air that is cleaner than Delhi, Pune and Ahmedabad, other cities where SAFAR monitors pollution levels.
Air quality is also predicted to be the best ever since SAFAR began monitoring it in Mumbai. “Winds over the city from Wednesday onwards are expected to shift from north-westerly to northerly [cool winds], with speeds of 9 to 11 km an hour, which is moderate wind speed,” said Gufran Beig, project director, SAFAR. “This will not allow pollutants to stay still and will disperse them fast.”
Of the 10 locations where air quality is measured in the city, according to the forecast, Bandra-Kurla Complex (BKC) will record the highest pollution levels on Diwali day (Thursday), followed by Nerul, Andheri, Chembur, Mazgaon and Borivli. The cleanest air in the city is expected at Worli.
SAFAR’s forecast said the highest levels of particulate matter (PM) are expected between 1am and 4am on October 20 (Thursday night to Friday early morning). “Air quality will start improving from Saturday because rainfall is expected on that day,” said Beig.
PM2.5 and PM10 are small particles, predominantly a part of dust, between 2.5 and 10 microns in size, and are considered unsafe because they can penetrate deeper into the lungs and enter the bloodstream. As against a safe limit of 60µg/m3 (microgrammes per cubic metre) for PM2.5, levels are expected to be close to 70µg/m3 on Diwali day, 90µg/m3 a day after Diwali, and drop close to the safe limit by Saturday. For PM10, the city is expected to record 120µg/m3 on Diwali and 140µg/m3 a day after Diwali, as against the safe limit of 100µg/m3.
“The most striking factor is that PM2.5 [relatively more harmful than coarser particles] is expected to increase by 20% during Diwali as compared to normal days,” the forecast said.
The pollutant-measuring indicator, or Air Quality index (AQI), is expected to be 84, which is below the ‘satisfactory’ range on Wednesday (October 18), ‘moderate’ at 114 on Thursday (Diwali day, October 20), ‘moderate’ at 191 on Friday, drop to 105 on Saturday, and finally 67 on Sunday under ‘satisfactory’. AQI level from 0-50 is considered good, 51-100 is satisfactory, 101-200 is moderate, 201-300 is poor, 301-400 is very poor, and 401 and above is severe.
On Tuesday, Mumbai recorded an AQI of 82 for PM2.5 and 83 for PM10, both falling under the ‘satisfactory’ category. However, a thin layer of smog was witnessed across the horizon during the evening hours.
Mumbai recorded high pollution levels last Diwali (October 30, 2016), with an AQI of 278 (poor) on Diwali day and 315 (very poor) the day after. In 2015, the city recorded an AQI of 279 (poor) on Diwali day (November 11) and 313 (very poor) the day after.