Mumbai needs a breath of fresh air, carbon monoxide levels beyond safe limit too

Just like particulate matter, the concentration of carbon monoxide (CO), too, has been much above safe levels in Mumbai, Pune and Solapur every winter from 2015 to 2019.

The safe limit for CO is 2 milligrams per cubic metre (mg/m3) for an eight-hour average. According to data from the Maharashtra Pollution Control Board (MPCB), CO concentration in Mumbai was 7% above safe standards in 2015-16, which increased to 10% in 2016-17 and 25% in 2017-18. A significant rise was witnessed in 2018-19, when the concentration was 50% above safe limits.

CO is a colourless, odourless, toxic pollutant formed as a result of incomplete combustion of carbon-containing fuels.

“A sharp rise in concentration of CO has been witnessed after the monsoon – October to February – every year for Mumbai, Pune and Solapur. The source is the rise in vehicular emissions, especially private ones, using petrol and diesel,” said E Ravindran, member secretary, MPCB.

“While particulate matter (PM10 and PM2.5) remains the prominent pollutant for our action plan for 17 major cities, reducing CO emission is also being targeted through enhancing the public transport and shifting to cleaner fuels (Bharat Stage VI) by April 2020.”

The rise was recorded at MPCB’s Bandra station (continuous ambient air quality monitoring station). Among the four years, CO concentration in the city was the highest during December 2018 and January 2019, at 3 mg/m3 and 2.2 mg/m3, respectively, with a marginal drop recorded from March. “This is an alarming rise and indicates emission from staggered vehicular movement daily,” said Anumita Roy Chowdhury, executive director (research and advocacy), Centre for Science and Environment.

In Pune and Solapur, the levels rose from 17% and 42% above safe standards in 2015-16 to 50% for Pune and 67% for Solapur above prescribed standards in 2018-19. At Solapur, CO concentration was above safe standards for seven consecutive months from September 2018 to March 2019, the highest since 2015.

Doctors said breathing air with high CO concentration may lead to reduced oxygen transport by haemoglobin.

“CO poisons the oxygen intake system and makes the body oxygen-deficient. With less oxygen over time, the poison may spread to various organs, including the brain. Traffic policemen, sanitation workers, children and senior citizens who spend more time in congested traffic zones are all susceptible to this form of pollution,” said Dr Sanjeev Mehta, pulmonologist and senior specialist, Lilavati Hospital in Bandra.

Every year, the MPCB records more than 1,000 observations for eight-hour averages for CO concentration. MPCB said directions had been issued to the state government to address CO for all three cities.

“Preparing an effective traffic management plan, better public transport network for citizens, adoption of electronic vehicles and necessary infrastructure for it are directions issued to the state. Timely servicing of vehicles and using public transport whenever possible are steps which can be taken by citizens,” said Ravindran.

First Published: Aug 26, 2019 00:38 IST