More than 60 million inhabitants of the Indo-Gangetic plain (IGP) are exposed to enormous concentrations of atmospheric health hazardous Black carbon (BC), a sooty material emitted by fossil fuel and the burning of agricultural waste among others, a study conducted by an international team, including researchers from IIT Kharagpur, has said.
They said that the black carbon leaves the natives of this region which has populous rural areas as well mega cities vulnerable to various cardiovascular diseases (CVDs), particularly during winter times.
During the research titled ‘Black carbon health impacts in the Indo-Gangetic plain: Exposures, risks, and mitigation,’ published in the latest issue of Science Advances, the authors found that the wintertime all-day black carbon surface concentrations for the urban belt and the megacities were about three and eight times higher, respectively, than the rural belt.
“People living in megacities such as Delhi and Kolkata are at greater risk of dying from CVDs. Black carbon contributes to 400,000 deaths annually over the IGP,” warned the researchers.
The researchers found that during wintertime, emissions of biofuel (BF) combustion for cooking and heating in the residential household sector accounted for more than 60 per cent of black carbon concentration over most of the IGP.
“The BF combustion in the residential sector (40 to 50 per cent) and FF combustion in industrial and transportation sectors (50 to 60 per cent) are dominant contributors to the wintertime black carbon concentration over the urban area in the central IGP (including Kanpur, Agra, and Varanasi).
“The wintertime black carbon concentration over the northern IGP (in and around megacity Delhi including the semirural area of Haryana) and eastern IGP (in and around megacity Kolkata) is found to be mainly more than 60 per cent originating from fossil fuel combustion,” said the study.
However, the researchers said that black carbon emissions from fossil fuel combustion sources such as diesel vehicles, coal-fired power plants and brick kiln industries could potentially be reduced by 87 per cent in urban areas and megacities. This could save about 160,000 lives in urban areas and 50,000 lives in megacities each year.
“The inhabitants can be saved by implementing prioritized emission reduction from the combustion of domestic biofuel in the semiurban area, diesel oil in transportation, and coal in thermal power plant and brick kiln industries in megacities in the region,” said the study conducted by Shubha Verma and Sanhita Ghosh, both from IIT Kharagpur, Olivier Boucher and Laurent Menut, both from France universities and Rong Wang from Fudan University, Shanghai .
Notably, the black carbon emission rate for rural/semirural population belts is lower by 15 times and 2 to 4 times the emission rates for megacity and semiurban/urban areas, respectively.
About 12 million people over the two megacities of the IGP (population density of more than 5000 people per km) are exposed to the extreme levels of wintertime all-day (daytime) black carbon concentration of magnitude as large as 40 µg m-3 (12 µg m-3), said the study.