Mumbai air was more dangerous than Delhi in 2016, says study

The quality of air in Mumbai was much worse than Delhi in the last two months of 2016, as it had a higher concentration of hazardous particulate matter (PM) than the capital.

The concentration of PM1 (smaller than one micrometre) was 45 microgrammes per cubic metre (µg/m3) in Mumbai in December 2016, against 42µg/m3 in Delhi, found the System of Air Quality Weather Forecasting and Research (SAFAR). In November 2016, the gap was narrow as Mumbai recorded 41µg/m3, against 48µg/m3 in Delhi.(File)

The concentration of PM1 (smaller than one micrometre) was 45 microgrammes per cubic metre (µg/m3) in Mumbai in December 2016, against 42µg/m3 in Delhi, found the System of Air Quality Weather Forecasting and Research (SAFAR). In November 2016, the gap was narrow as Mumbai recorded 41µg/m3, against 48µg/m3 in Delhi.

PM, which consists of dust, chemicals, pollen, soot, and liquid suspended in air, is hazardous because it can enter the lungs. PM ranges from coarse (bigger) particles that are visible to the naked eye, such as dust and sand to much smaller particles such as PM10 (less than or equal to 10 micrometres), PM2.5 (less than 2.5 micrometres) and PM1. One micrometer is about a thousandth of a millimeter.

According to the data, the PM1 levels were 35µg/m3 and 40µg/m3 in November and December 2015, respectively.

“PM1 level in Mumbai was as high as Delhi in winter due to a combination of high salty humidity, coming from the sea, and low temperature that makes them suspend longer in Mumbai,” said the conclusion of the study.

SAFAR’s assessment was made on the basis of a year-long analysis of PM1 levels recorded at their Lodhi Road station, and averaged data from 10 SAFAR stations in Mumbai. There is no permissible standard specified for PM1 even at an international level due to limited data for PM1 measurement at a global level.

Officials from SAFAR said PM1 in urban pollution is predominantly composed of exhaust from internal combustion in motor vehicles. “The probability of inhaling PM1 particles is high as they stay suspended in the air much longer compared to coarser particles,” said Gufran Beig, scientist at Indian Institute of Tropical Meteorology (IITM) and project director, SAFAR. “The winter is a concern for Mumbai as the holding capacity of tiny particles in the air is high with low temperatures and high humidity. In summer and monsoon, the rise in temperature makes the difference.”

Doctors said that fine PM1 particles could cause maximum damage to the respiratory system compared to any other pollutant. “These small particles can travel to the bloodstream and can affect our cerebral system,” said Sanjeev Mehta, pulmonologist (lung specialist), Lilavati Hospital, Bandra. “These fine particles can trigger health ailments such as chronic obstructive pulmonary disease (COPD), bronchitis, hypersensitivity pneumonitis (inflammation of lung tissue) and asthma. It is advisable to see your nearest physician if cough and cold persists for 10 days or more during winter months in Mumbai.”