The fire at the Deonar dumping ground in January visibly worsened Mumbai’s air quality. Though the smog cover made visible the harmful effects of the fire, it was contextualised through the Air Quality Index (AQI), which was at an alarming level of 341, on par with pollution-prone Delhi. The System of Air-quality-weather Forecasting and Research (SAFAR) has been calculating the AQI, a globally used parameter to measure and disseminate air pollution levels, in Mumbai since June through its 10 centres across the city.
An initiative under the Ministry of Earth Sciences for metropolitan cities to determine strategies to mitigate air pollution, the AQI calculates the presence of pollutants like particulate matter, ozone and carbon monoxide in the air. With increasing pollution levels in cities like Mumbai, AQI has become a handy tool to determine policies to reduce it.
To keep check of the air quality data, SAFAR monitoring stations have been spread across the city. “Apart from their geographical location, other components such as the suburb with a proximity to the sea, like Colaba and Worli, the presence of industries like Chembur and Navi Mumbai, their adjacency to congested traffic areas like Andheri, Bandra-Kurla complex, have determined the position of the monitoring centres,” explained Dr Gufran Beig, project director, SAFAR.
Each centre has an Air Quality Measurement System (AQMS), which has the equipment to measure air quality. At one such centre in Colaba, within the premises of the Indian Meteorological Department, the AQMS is managed by two staffers. Aakash Ahir, one of the staffers and a service engineer with SAFAR, explains that a vent traps air from the atmosphere and transfers it to another moisture trap to remove moisture and bring it to a temperature at which it can be analysed.
“The air is then sent to separate ducts to measure each pollutant. The data, measured on a real-time basis, is added to a software, which reflects an average of the AQI every 15 minutes,” Ahir said. This data is further sent to a server, which uploads it on the SAFAR mobile app, its website and flashed across several traffic junctions in the city.
The AQMS is equipped to measure temperature, pressure, humidity, UV, wind direction, wind speed apart from the presence of pollutants.
Depending on the wind speed and its direction, it reflects the air pollution of more than 5km radius from where the system is located. Researchers associated with SAFAR further analyse particular patterns and trends in the AQI. The color coded way in which the data is presented along with health advisories makes it easier for people to take particular precautions, Ahir told The Indian Express.
Analysing the data, researchers also immediately notice extreme changes in the AQI of a particular area. For instance, the Deonar dumping fire, led to an increase in pollution levels at all centres. “A few weeks ago in Mazgaon, which usually has AQI between moderate and good, was suddenly poor. We realised that trees were being cut in the area,” said Ahir. Apart from external factors like wind speed, traffic congestion, construction activity too determine changes in the pollution level. “If a road is being dug up or a multi-storey building is being constructed, it generates a lot of dust and increases the PM levels in the area,” he added.
The staffers said that the display of AQI on the city’s roads has led to an awareness about it which they are hopeful will lead to advocating for better air quality. “The odd-even scheme was tried in Delhi because the residents were aware of how bad the air quality was. The awareness about the air quality will hopefully lead to people contributing to making it better like using public transport or carpooling in Mumbai,” Ahir said.