Funeral Pyres in South Asia: Brown Carbon Aerosol Emissions and Climate Impacts

Atmospheric heating caused by anthropogenically emitted carbonaceous aerosols contributes to one of the largest uncertainties in climate forcing over south Asia (SA). Past studies have identified the combustion of fossil fuels and residential biofuels as being the dominant emitter of light-absorbing black carbon aerosols over this region. Here, we measure emissions from open-air burning of funeral pyres, a deep-rooted and widely prevalent custom in SA, and find that large amounts (≈98% by mass) of light-absorbing organic carbon (OC) aerosols, optically defined as brown carbon (BrC), are emitted per kilogram of feedstock burned. The emitted OC contributes an average 40% to the smoke particulate matter absorption of the visible solar radiation. We calculate funeral pyres in SA contribute approximately 92 Gg of light-absorbing OC annually, which is equivalent to ≈10 and 23% of the carbonaceous aerosol mass from regional biofuels and fossil fuels, respectively. Our findings underscore the importance of accounting for cultural burning practices as aerosol sources in emission inventories and BrC aerosols in climate models, as well as the development of mitigation strategies.