Decline in Black Carbon Level in Varanasi | 09 Jul 2024

According to a study at Banaras Hindu University (BHU), an annual average decline of 0.47 micrograms per cubic metre in carbon level has been observed in Varanasi and the central Indo-Gangetic plains.

The study utilized black carbon data generated under the Aerosol Radiative Forcing over India (ARFI) program of the Indian Space Research Organisation (ISRO).
- An analysis of a decade-long measurement of black carbon mass concentration was conducted at a representative location in the central Indo-Gangetic plain, Varanasi, from 2009 to 2021.
- The purpose of this analysis was to understand the physical, optical, and radiative impact of black carbon in this region.
The study recorded an average annual decrease of 0.47 micrograms per cubic metre in black carbon levels.
- Black carbon levels also showed a consistent seasonal decline, with a post-monsoon average decrease of 1.86 micrograms per cubic metre and a pre-monsoon average decrease of 0.31 micrograms per cubic metre.
The study found that the black carbon in Varanasi and central Indo-Gangetic plains mostly originates from distant sources, rather than local factors.
- These particles are transported over long distances from the lower and upper Indo-Gangetic plains, Pakistan, the Middle East, and southern peninsular regions.

Black Carbon (BC) is a short-lived pollutant that is the second-largest contributor to warming the planet behind carbon dioxide (CO2).
Unlike other greenhouse gas emissions, BC is quickly washed out and can be eliminated from the atmosphere if emissions stop.
Unlike historical carbon emissions it is also a localised source with greater local impact.
Black carbon is a kind of an aerosol.