Morphological and Elemental Classification of Freshly‐Emitted Individual Particles From Field and Laboratory Residential Biomass Burning

Abstract

Residential biomass burning significantly contributes to air pollution in developing countries. However, the microscopic properties of individual particles in their emissions have not been well understood. In this study, individual primary particles from 14 kinds of biomass fuels (including firewood, crop residue, and animal dung) were collected in laboratory and field measurements, and their morphology, composition and mixing state were acquired using transmission electron microscope. These results constitute a source profile database of individual primary particles from residential biomass burning. The database reveals that different types of biomass fuels exhibit different emission characteristics, that is, residential firewood burning mainly emits pure carbonaceous particles (including organic matter (OM) and soot particles), crop residue burning mainly emits K‐containing particles (including OM‐K, soot(‐OM)‐K, and K‐rich particles), and animal dung burning mainly emits pure carbonaceous particles and K‐containing particles. Moreover, our results indicate that the emission characteristics obtained from laboratory and field measurements are different. Field measurements conducted in two selected villages in North China Plain exhibit a higher presence of soot particles compared to laboratory measurements, owing to their higher combustion temperatures. In contrast, field measurements conducted in one selected village in Qinghai‐Tibet Plateau contain less soot particles than those from laboratory measurements in plain areas, due to the deficient oxygen supply during combustion process in the high‐altitude regions. These results warn us that the emission estimation from residential biomass burning should notice the large emission differences among different biomass types and between field and laboratory measurements.