In a city that’s always on the move, it’s hardly surprising that vehicular emissions are one of the major sources of air pollution in the city. And even though only 23% of the population uses private vehicles, the number of privately-owned two-wheelers and cars outstrip public transport vehicles.
In a span of five years, up to 2012, the city added five lakh new private vehicles to its roads – from 15 lakh to 20.35 lakh – reducing peak hour traffic speed to a mere 10kmph.
But the ill-effects of vehicles crowding city roads goes beyond just traffic snarls— it’s affecting your health and making the air you breathe hazardous. Rush-hour traffic congestion leads to fuel wastage and increased emission of pollutants such as nitrogen dioxide (NO2), carbon monoxide (CO) and respiratory suspended particulate matter (RSPM). These pollutants enter your lungs, weaken your respiratory organs and can lead to respiratory illnesses. Experts have warned that the proliferation of private vehicles will only degrade the air further.
Recent studies by environmental agencies paint a grim picture of air pollution levels in the city, and highlight the contributory role played by excessive use of motor vehicles.
The latest ambient air quality monitoring data recorded by the Maharashtra Pollution Control Board (MPCB) at Sion shows that the average NO2 level in January this year — 171.11 micrograms/metre cube (ug/m3) — is twice the permissible level of 80 ug/m3. On January 26, the NO2 levels reached a whopping 229 ug/m3, the highest this year.
National Environmental Engineering Research Institute’s (NEERI) six-city study on air quality in November 2010 showed that vehicular pollution is the biggest source of NO2 in Mumbai.
NEERI looked at air quality at seven locations in the city – Colaba, Dadar, Dharavi, Andheri, Khar, Mahul and Mulund — revealing that Dadar, one of the major junctions with roads leading to the eastern, western and southern parts of the city, witnessed the highest concentration of NO2, CO, particulate matter (PM) and sulphur dioxide (SO2) in a 24-hour cycle.
The study also revealed that maximum NO2 and CO2 emission load was contributed by heavy-duty diesel vehicles.
Air pollution becomes a bigger concern in winter, when the concentration of pollutants reaches its peak, as the colder air traps pollutants close to the ground and prevents them from dispersing easily. The haze that forms over the city in the mornings is actually a blanket of pollutants, and can be very harmful.
“Unlike summer and monsoon, the sea breeze is not as strong during winters. This prevents dispersion of RSPM and dust into the atmosphere,” said Rakesh Kumar, chief scientist and head, NEERI, Mumbai.
The major infrastructural development of the city is also to blame for rising pollution, and this will only get worse in coming years, experts said. “With several infrastructure projects under construction in the city, the concentration of dust and RSPM levels are bound to increase,” said Kumar
To help counter this, NEERI is going to experiment with a model called the Diffused Air Pollution Reduction method, to disperse pollutants from small sections on busy roads. Air filters will be fitted on road dividers, to facilitate the dispersion of pollutants.
“With the increase in housing societies on arterial roads such as LBS Marg, the vehicular load on these roads will shoot up. NEERI is soon going to run a pilot test of the project. Solar powered blowers are one of the equipment that can be used to reduce concentration of pollutants,” said Kumar.