Pollutant emissions from biomass burning: A review on emission characteristics, environmental impacts, and research perspectives

Abstract

Biomass is one most abundant resource on the earth providing important energies in support of socioeconomic development in many areas. Burning of biomass fuels comprises to nearly 10% of the total energy from anthropogenic combustion processes; however, as the burning is usually incomplete, this process yields products of incomplete combustion posing consequently significant impacts on air quality, human health, and climate change. Here, we analyzed spatiotemporal characteristics in intentional and unintentional biomass burning from different sectors, discussed impacts of biomass burning emissions on indoor and outdoor air quality, and consequent influences on human health. The global total consumption amount of biomass including both natural and anthropogenic sources was approximately 7900 Tg in 2019, with significantly large regional and sectorial discrepancies among regions. Globally, anthropogenic biomass burning amounts increased gradually, but notably in some developing countries like China residential consumption of biomass fuels, as one large sector of biomass use, decreased over time. Uncommercial biomass consumption needs to be accurately quantified. There are relatively rich datasets of pollutant emission factors from biomass burning, including laboratory and field tests, but still large variations exit and contribute substantially to the uncertainty in emission inventory. Global primary PM2.5, black carbon and organic carbon emissions from biomass burning were about 51, 4.6, and 29 Tg, respectively, contributing to nearly 70%, 55%, and 90% of the total emission from all sources, and emissions from the residential sector and open fires are major sources. Brown carbon emissions from biomass burning attracts growing interests but available studies adopted different methodologies challenging the comparability of those results. Biomass burning emissions polluted not only ambient air but more severely indoor air quality, adversely affecting human health. Future studies that should be emphasized and promoted are suggested.