The Kathmandu Valley in Nepal, the largest metropolitan region in the Himalayan foothills, has been experiencing severe air pollution over recent decades due to rapid and unplanned urbanization and diverse local and regional emission sources. 

However, there are few studies regarding the light absorption characteristics of carbonaceous aerosol (CA) in the Kathmandu Valley, which is essential for a better understanding its effects on air pollution and climate change over the region. 

Recently, a research group led by Prof. KANG Shichang from Northwest Institute of Eco-Environment and Resources, together with scholars from domestic and foreign research institutes and universities, collected total suspended particles (TSP) samples in the Kathmandu Valley from April 2013 to January 2018 to analyze organic carbon (OC), elemental carbon (EC) and water-soluble organic carbon (WSOC) and their respective light absorption characteristics. 

Scientists observed a clear seasonal variation for all carbonaceous components with higher concentrations occurring during colder months and lower concentrations in the monsoon season. 

Besides, scientists also indicated that both EC and WS-BrC should be considered in the study of optical properties and radiative forcing of carbonaceous aerosols in this region. 

This study has been published on the Environmental Pollution in an article entitled “Light absorption properties of elemental carbon (EC) and water-soluble brown carbon (WS-BrC) in the Kathmandu Valley”.