The study compared Environment Status Reports (ESR) from the Brihanmumbai Municipal Corporation (BMC) between 2006 to 2012 and National Environmental Engineering Research Institute (NEERI) data for the city from 2000 to 2006.

The analysis showed that SPM concentration increased from 2000, with a significant increase since 2006. As against the safe limit of 140 microgrammes per cubic metre (µg/m3), Mumbai recorded SPM levels at 1,056 µg/m3 in 2007-08 — seven times the safe limit. By 2012, levels increased to 1,853 µg/m3, 13 times the safe limit. BMC’s pollution data for 2015-16, taken from the System of Air Quality Weather Forecasting and Research (SAFAR), which collects pollution data from 10 locations in the city, recorded PM10 (pollutants smaller than 10 microns in diameter) and PM2.5 levels were above permissible limits at all locations.

The study, Changing Air Quality and its Impact: A case study of Mumbai, was published by the International Journal of Scientific Research last week. Narinder Kaur, assistant professor, Smt MMK College of Commerce and Economics, Bandra, who did the analysis, said,“Continuous emissions of harmful pollutants, especially SPM, are responsible for rising discomfort, and increasing airborne diseases in Mumbai,” said Kaur. “Open burning of municipal solid waste on the streets and landfill sites needs to be stopped immediately to improve the city’s air quality.”

The study said fuel combustion — by vehicles, power stations and industries, construction activities, road dust, burning of garbage and use of wood and dung as cooking fuel — as the main sources of SPM. “The quality of air in an area determines the health of people. It was observed that increased exposure to SPM in Mumbai is resulting in various respiratory diseases such as lung cancer, asthma, bronchitis, pneumonia and even heart disease,” said Kaur.

Doctors said there had been a significant rise in patients visiting them, complaining of respiratory infections mostly related to particulate matter. “SPM carries virus and bacteria, which infect the lungs and cause infections. Those suffering from these problems rarely respond to common medicines,” said Dr PratitSamdani, physician, Breach Candy Hospital.

Sanjeev Mehta, pulmonologist, Lilavati Hospital, Bandra, said the percentage of patients diagnosed with respiratory ailments concerned with SPM has doubled between 2007 and 2017, compared to the earlier decade. “We observed a decrease in lung function even when they are healthy or not even smokers,” said Mehta.

A report by International Agency for Research on Cancer (IARC), cited in the study, found young children to be worst affected by the impact of SPM. “Cases of birth defects, lower intelligence quotient and premature deaths have all been identified as a direct impact of exposure to toxic pollutants like SPM in Mumbai’s air,” she said.

“The personal exposure for Mumbaiites to pollution, especially particulate matter, is very high, which has serious health consequences. Mumbai needs a comprehensive air pollution action plan, and it should be stringently implemented in a time-bound manner,” said AnumitaRoychowdhury, executive director, in-charge of clean air and sustainable cities programme, Centre for Science and Environment (CSE

Other air pollutants such as nitrogen dioxide (NO2) and sulphur dioxide (SO2) showed an increase during some years between 2007 and 2012, they did not show a clear rising trend like SPM.

The air you breathe:

Suspended Particulate Matter (SPM) is a mix of dust, chemicals, soot, pollen, water droplets and other organic substances.

SPM is released during fuel burning - by vehicles, power stations and industries, construction activities, road dust, burning of garbage and use of wood and dung as cooking fuel.

The particles can enter the lungs and get lodged in the tissues, causing respiratory illnesses.