Why has AQI deteriorated in Mumbai? | Cities News – The Indian Express

According to the System of Air Quality Forecast and Research (SAFAR), Mumbai’s AQI readings were in the ‘poor’ category throughout this week, ranging between 220 and 260.

As per SAFAR’s AQI monitoring chart, AQI of 0-50 is ‘good’, while it is ‘satisfactory’ at 51-100, ‘moderate’ at 101-200, ‘poor’ at 201-300 . The ‘very poor’ category denotes AQI of 301-400 and beyond 400, it is labelled ‘severe’.

While the overall AQI on Friday morning was at 173 (moderate), several pockets of the city continued to see worse AQI. Mazagaon had an AQI of 328 (very poor), followed by an AQI of 215 in Colaba and 208 in Chembur. Borivali showed an AQI of 183, followed by 156 in Bandra Kurla Complex (BKC) and 135 in Andheri. Worli recorded the best AQI of 90, followed by 125 in Bhandup.

Why has AQI worsened?

Meteorologists and weather experts have attributed the dip in AQI mainly to the changing weather in Mumbai. Senior scientist and founder project director of SAFAR, Dr Gufran Beig says now that the monsoon has withdrawn from Mumbai, airspeed has slowed down, which is letting the suspended particulate matter stay in the lower atmosphere for longer hours, which eventually deteriorates the overall AQI.

“The present condition is due to the drop in temperature accompanied by north-easterly winds blowing in less than 10 kmph speed, which favours less dispersion (of pollutants) and hence high AQI,” Beig told The Indian Express.

He said while the overall AQI of the city ranges between moderate and poor, there are areas that record worse AQI throughout the day. “The AQI in areas like Malad and Mazagaon is between poor and very poor. This is because Malad remains cooler compared to other areas in Mumbai during winter and is also away from sea breeze, so normally it has high AQI during winter. The same equation is applicable to other pockets of the city, which record high AQI,” Beig added.

How long will the AQI remain bad?

Experts have said that Mumbai will continue to record AQI in the ‘poor’ and ‘moderate’ categories till the end of winter. “As the temperature falls, Mumbai will continue to see poor AQI on and off until January. After winter recedes, the AQI will start rising,” Beig explained.

Mahesh Palawat, meteorologist and climate expert from Skymet Weather Services Private Limited said two factors mainly determine a region’s AQI – air speed and daily temperature. “The decline in temperature has led to the development of mist and haze. These types of conditions enhance the pollution level and since the airspeed is also very low, the pollutants don’t disperse easily from the lower atmosphere,” Palawat told The Indian Express.

He said areas which record heavy traffic and low wind speed will continue to show worse AQI till the end of the season. “Towards the weekend, north-easterlies will start blowing which may improve the overall AQI by some margin. Even though pollutants and suspended particulate matter will be there, the quality will improve mainly in places that are close to the sea and experience good amount of breeze. This is due to dispersal of particulate matter which will happen due to increased wind speed,” said Palawat.

How will it affect Mumbaikars?

The primary pollutants that lead to high AQI are PM2.5 components, which are air particulate matter that have a diameter of less than 2.5 micrometres. PM2.5 components comprise burn residues, dust particles and components discharged from vehicular emissions.

Doctors and health experts have advised citizens, who mainly hail from vulnerable groups, to use masks while stepping out of their homes. Experts have also advised installation of air purifiers as a safety measure in pockets that show poor AQI.

“The high AQI mainly impacts children and senior citizens with co-morbidities and may affect their lungs directly. Therefore, it is advisable to use masks while stepping out and avoid going out at peak traffic hours, since vehicular emission is maximum during this time. Post Diwali, the AQI in Mumbai has shown a significant drop, which has also led to an increase in patients coming for treatment for lung diseases,” said city-based pulmonologist Dr Ashutosh Shah.