Major Air Pollution By Transport sector

  • pollution free environment magazine

Indians losing life expectancy due to air pollution from the transport Sector

A lot of confusion seems to exist over what really contributes to air pollution, particularly PM2.5 (fine, respirable particles) from the transport sector or from vehicles in Delhi. A letter accessed by TOI written by IIT professor Dinesh Mohan to the transport ministry claims that people may be overestimating the "pollution load from traffic" and that there may be a huge difference in the actual number of vehicles on the road as compared to those registered officially.


Mohan quotes a 2013 study that concluded that the transport sector is responsible for only 17% of PM2.5 emissions as compared to 15% from brick kilns and as much as 12% from LPG or domestic sector. The transport ministry has submitted the letter to National Green Tribunal to deflect some attention from the transport sector and pollution load from old vehicles. Recently, they filed an application quoting from Mohan's letter to appeal for six months time to come up with suggestions to curb air pollution.

The GIS-based emissions inventory by Saratha Guttikunda of Desert Research Institute (DRI), which Mohan quoted, estimates PM2.5 pollution from transport to be far lower than another study by scientists of Indian Institute of Tropical Meteorology (IITM). This study, also GIS-based and conducted by chief programme scientist Gufran Beig, found PM2.5 emissions from transport to be 32% in 2010 and steadily increasing in later years. Guttikunda's estimation seems to be far lower than even a Chinese government's recently released emissions inventory for Beijing that estimates more than 30% of PM2.5 emissions in the city are from "mobile sources".

The government has no consensus on which data to go with. Delhi Pollution Control Committee commissioned a similar emissions inventory to IIT Kanpur's professor Mukesh Sharma, which is likely to be concluded in September and may help clarify on pollution sources. Meanwhile, scientists told TOI there should be no doubt that transport is the biggest culprit in terms of PM2.5 emissions. "There is a lot of difference between emission contribution and actual pollution or the air quality people breathe. For instance, power plants or brick kilns are elevated, almost 300 metres above the breathing zone, while tailpipes are near our noses. That's what contributes to the worst health impacts from PM2.5 emissions. I don't think there should be any confusion on this," said a government scientist on the condition of anonymity.

Anumita Roychowdhury of Centre for Science and Environment clean air campaign said, "From the public health perspective, proximity to the pollution source is most important. The Health Effects Institute, for instance, found the worst affected are those within 500 metres from the roadside. They estimated about 55% of people in Delhi live within that 500 metres, so vehicles are the major concern."