Emission Characterization of Indoor and Outdoor Biomass Combustion Sources Across the Indo-Gangetic Plain, India

Biomass burning remains a dominant source of air pollution across the Indo-Gangetic Plain (IGP), yet emission inventories often rely on limited source characterization and do not fully represent the diversity of fuels used in real household and outdoor environments. Emission factor (mass of pollutants per kg of biomass burned) of pollutants is the key input for emission inventory as well as for modelling the emission into exposure concentration. This study attempts to characterize emission factor of the various pollutants (gases and particles) arising from 25 commonly used biomass fuel types representative of rural IGP. Gas-phase measurements included CO2, CO, SO2, NO, NO2, and total hydrocarbons. Aerosol emissions were quantified in terms of particle number and particle mass concentrations, with detailed chemical characterization of PM2.5, including water-soluble inorganic ions, trace metals, organic carbon, elemental carbon, water-soluble organic carbon, water-soluble total nitrogen, and polycyclic aromatic hydrocarbons. This approach enabled the development of source-specific emission profiles for a wide range of commonly used biomass fuels. Results reveal substantial variability in emission characteristics across fuel types, reflecting differences in fuel composition and combustion conditions. The findings provide a more representative dataset for biomass burning emissions over IGP and highlight the importance of incorporating locally relevant fuel diversity into regional emission inventories and atmospheric models. These results improve understanding of the contribution of household and outdoor biomass burning to regional air quality, atmospheric chemistry, and climate-relevant aerosol properties.