Attributed radiative forcing of air pollutants from biomass and fossil burning emissions.

Energy is vital to human society but significantly contributes to the deterioration of environmental quality and the global issue of climate change. Biomass and fossil fuels are important energy sources but have distinct pollutant emission characteristics during the burning process. This study aimed at attributing radiative forcing of climate forcers, including greenhouse gases but also short-lived climate pollutants, from the burning of fossil and biomass fuels, and the spatiotemporal characteristics. We found that air pollutant emissions from the burning process of biofuel and fossil fuels induced RFs of 68.2 ± 36.8 mW m-2 and 840 ± 225 mW m-2, respectively. The relatively contribution of biomass burning emissions was 7.6% of that from both fossil and biofuel combustion processes, while its contribution in energy supply was 11%. These relative contributions varied obviously across different regions. The per unit energy consumption of biomass fuel in the developed regions, such as North America (0.57 ± 0.33 mW m-2/107TJ) and Western Europe (0.98 ± 0.79 mW m-2/107TJ), had higher impacts of combustion emission related RFs compared to that of developing regions, like China (0.40 ± 0.26 mW m-2/107TJ), and South and South-East Asia (0.31 ± 0.71 mW m-2/107TJ) where low efficiency biomass burning in residential sector produced significant amounts of organic matter that had a cooling effect. Note that the study only evaluated fuel combustion emission related RFs, and those associated with the production of fuels and land use change should be studied later in promoting a comprehensive understanding on the climate impacts of biomass utilization.