Black carbon emitted due to indiscriminate burning of paddy and sugarcane stubble has not only put the National Capital Region (NCR) under severe stress of pollution but because of its light-absorbing nature can also trigger melting of the Gangotri glaciers in the high altitude eco-sensitive Indian Himalayas in India.
Scientists from Wadia Institute of Himalayan Geology, (WIHG) an autonomous institution under Department of Science and Technology in their study conducted at Chirbasa station (3600 m) near Gangotri Glacier in 2016 found that black carbon concentration changed from 0.01?gm?3 in winter to 4.62?gm?3 during summer, ie spiked by 400 times during summer.
This is for the first time, measurements on ambient black carbon mass concentration were made at such a high altitude site in the Indian Himalayas.
The study suggests that seasonal cycle of black carbon was significantly influenced by the emissions resulting from agriculture burning (in western part of the country), forest fires (along the Himalayan slopes) in summer, and to some extent the contribution from long range transport of pollutants in winter, depending the prevailing meteorological condition as the reason behind this seasonal increase.
The research led by Dr PS Negi from WIHG was published in the scientific journal Atmospheric Environment.
It was revealed by investigating the occasional high values of black carbon extricated, that the seasonal cycle of increase was significantly influenced by the emissions resulting from agriculture burning (in western part of the country), forest fires (along the Himalayan slopes) in summer, and to some extent by the contribution from long-range transport of pollutants in winter, depending the prevailing meteorological condition.
This can trigger glacial melt because of the light-absorbing nature of black carbon, said the study, “Black carbon aerosols in the ambient air of Gangotri Glacier valley of north-western Himalaya in India.”
“The monthly mean concentration of black carbon was found to be minimum in August and maximum in May. The observed seasonal mean concentrations of black carbon indicated a pristine glacial source and absence of black carbon sources in the locality,” said the study.
The Equivalent Black Carbon (EBC) aerosols contribute significantly towards global warming due to its light-absorbing nature. Their presence in the eco-sensitive zone, such as the Himalayan glacier valleys, is a matter of serious concern and needs to be meticulously monitored. However, baseline data on BC is rarely available from most of the glaciated Himalayan region, said the 0study.