Black carbon is the most strongly light-absorbing component of particulate matter (PM), and is formed by the incomplete combustion of fossil fuels, biofuels, and biomass. It is emitted directly into the atmosphere in the form of fine particles (PM2.5) and is considered to be a very strong agent of global warming.

On Wednesday, students and researchers from the civil engineering department of Indian Institute of Technology-Guwahati (IIT-G) will record specific emission of black carbon particles by vehicles at one specific traffic point i, the city.

The study, titled 'Urban Black Carbon Emission-Its Global Impact and Local Mitigation', will be carried out jointly by the Union department of science and technology and the civil engineering department of IIT-G for a year.

Six locations in the city, which see high vehicular traffic, have been selected for the study. These are: Bamunimaidam, Kamakhya Gate, Athgaon, AT Road, Lachit Nagar, Lokhara and Khanapara.

Besides the effect of air pollution on public health, the study will focus on how black carbon emission contributes to melting of snow in the Himalayas.

"We want to see how black carbon moves towards the Himalayas depending on wind movement. We will calculate the thickness of black carbon emission and determine how long it stays in the atmosphere. Through the study, we will be able to know how emission from the city contributes to global warming," said Sharad Gokhale, professor of environmental engineering, department of civil engineering at IIT-G.

"On Wednesday, our researchers and students will take specific measurement of black carbon emission from one location. We initially spent some time on trial and field work. The study is aimed at improving public health also," Gokhale added.

Imported and expensive instruments like the Aethalometer, Fine Particle Sampler and Sun Photometer will be used for the study. The team will visit each of the six locations during different seasons.

Black carbon is only second to carbon dioxide in causing global warming. Its emission is growing and it heats the earth's atmosphere by absorbing sunlight.

Guwahati and some cities in the region have reported a drastic drop in air quality in the past few years, according to the World Health Organization's Ambient (outdoor) Air Pollution in Cities Database that was released in April 2015.

Guwahati, Roha, Sivasagar and Silchar in Assam and Dimapur in Nagaland have each reported particulate matter (PM) 2.5 annual mean of 40, 53, 48, 40 and 40 microgram per cubic meter, respectively. The WHO's safety threshold of PM 2.5 for humans is 10 microgram per cubic meter annual mean. The report covered 1,600 cities and focused on data collected from monitoring stations between 2008 and 2013.