Queen of the Hills goes up in smoke... Highest concentration of Black Carbon..

Joydeep Thakur, THT, KOLKATA: Darjeeling, 15 December 2013: the Queen of the Hills, once famous for its sanitariums, has turned out to be the most polluted hill station in India and Nepal, notching up a level of pollution higher than cities such as Ahmedabad, Bangalore and Trivandrum.The study awaiting publication by an international science journal is the result of a two-year research by scientists of Bose Institute in Kolkata.
“The black carbon (soot) burden over Darjeeling was found to be much higher than other hill stations including Nainital, Mukteshawar, Ladakh, Dehradun and those in Nepal. Its pollution level is also higher and sometimes comparable with other metro cities,” said Abhijit Chatterjee, environmental scientist with the Bose Institute who led the study.
It was funded by the Union ministry of science and technology. Black carbon absorbs 100% solar radiation and has hence emerged as a major contributor to climate change, possibly second only to carbon dioxide. When deposited over snow, black carbon can reduce the ability to reflect sunlight, thus hastening melting of glaciers.
Apart from black carbon, the air of Darjeeling is also full of fine particles easily inhaled and could trigger asthma, low birth weight, heart attack and lung cancer among other diseases.
The highest concentration of black carbon was found in the pre-monsoon months followed by winter (December –February), post-monsoon (October– November) and minimum during the monsoon (June– September) in this hill station more than 600 km north of Kolkata.
Bose Institute scientists collected the data every five minutes over a period of two years between January 2010 and December 2011 and analysed these recently. The scientists are waiting for the paper to be published in an international journal.
This is the first study of the characterisation of black carbon aerosols (particulate matter) in the eastern Himalayas in India. The team comprised other eminent scientists including C Sarkar, AK Singh and SK Ghosh. Sibaji Raha, director of the Bose Institute, coordinated the project. 
Earlier studies on black carbon made over Himalayas made by scientists of various institutes were mostly limited to northern, northwestern, western Himalayas and Nepal.
“Primary sources of black carbon include emissions from diesel engines, cook stoves, wood burning and forest fires. Huge number of mostly diesel-driven vehicles carrying tourists and locals is one of the most important triggers for the high doses of carbon in the hill station.
Other activities such as burning of plastic, tyres and other articles during the winter also add to the level,” said Raha. “During the pre-monsoon season (March to May), westerly winds from north-west and west India, pick up dust and other carbonaceous aerosols from several polluted cities all along their way including Delhi, Kanpur and Allahabad and deposit them in the foot fills of the eastern Himalayas. This worsens the condition,” said Chatterjee.
With Kanchendzonga and other adjacent peaks just around 80 km from Darjeeling ( as the crow flies) the team raised concerns over the future of east Himalayan glaciers because if these particles reach the mountains and settles on the snow, it would hasten the melting of glaciers.