Review of Brown Carbon Aerosols in China: Pollution Level, Optical Properties, and Emissions
Qiaoqiao Wang, Yuyi Zhou, Nan Ma, Yong Zhu, Xiaocong Zhao, Shaowen Zhu, Jiangchuan Tao, Juan Hong, Wenjie Wu, Yafang Cheng, Hang Su
Abstract
Abstract Brown carbon (BrC) has been recognized as an important contributor to global warming due to its absorption of solar radiation with strong wavelength dependence. While early studies mostly consider biomass burning as a major emission source, a few recent studies have suggested coal combustion and vehicle exhaust as important contributors to BrC emissions. Considering dominant coal consumption, large residential biofuel usage, and the increasing number of vehicles, BrC pollution could result in remarkable regional climate effects in China. This study gives an overview of sources, chemical composition and absorption properties of BrC, focusing on BrC categorization and its absorption measurement techniques. The basic pollution features of BrC in China, including surface concentrations, column burden, sources and associated absorbing properties are then summarized and compared to other countries. BrC emissions as well as its optical emission at 365 nm from the primary sources in China are also summarized to provide a more straightforward understanding of the light‐absorbing properties of BrC in China. With a detailed comparison of existing publications, the study gives deeper insight into the uncertainties in BrC measurements and will improve the understanding of the climate effect of BrC. The review also recommends key research areas for further investigation of BrC in the future.