The lack of aerosol type information has largely hindered satellite products from further applications such as constraining model simulations and quantifying aerosol climate effects. The recent Version (V) 23 Multi‐angle Imaging Spectroradiometer (MISR) aerosol products with an enhanced spatial resolution at 4.4 km enable an unprecedented chance to explore aerosol types and associated processes in the regional scale. Here we provide a comprehensive insight into the characterization of MISR aerosol optical and microphysical properties, as well as their performance, over East Asia. Ground validation shows a remarkable improvement in the accuracy of V23 MISR aerosol optical depth (AOD) with ~80% of its retrieval bias within ±(0.05 + 20%AOD_AERONET). However, an underestimation of MISR AOD is still prevalent in the high‐AOD (>0.6) conditions, due to the surface‐atmosphere separation problem and insufficient absorbing aerosol mixtures being selected. MISR AOD of different size bins agrees well with AErosol RObotic NETwork (AERONET) results, demonstrating an evident advantage in discriminating natural dust from anthropogenic particles. Although MISR nonspherical and absorbing retrievals display a consistent variation with the AERONET inversions, their component AODs have a poor reliability over East Asia due to the inappropriate aerosol component models or their mixtures as in V22. In particular, the most striking problem is the sparse and discrete MISR absorbing retrievals with spatial discontinuity. Generally, the high‐resolution V23 MISR products exhibit a great potential in characterizing the regional variations of aerosol type, which can be further refined by considering the prior aerosol knowledge over East Asia.

The long-range transport of biomass burning pollutants from Southeast Asia has a significant impact on air quality in China. In this study, the Moderate Resolution Imaging Spectroradiometer (MODIS) fire data and aerosol optical depth (AOD) products and the Tropospheric Monitoring Instrument (TROPOMI) carbon monoxide (CO) data were used to analyze the impact of air pollution caused by biomass burning in Southeast Asia on southern China. Results showed that Yunnan, Guangdong and Guangxi were deeply affected by biomass burning emissions from March to April during 2016–2020. Comparing the data for fires on the Indochinese Peninsula and southern provinces of China, it is obvious that the contribution of pollutants emitted by local biomass burning in China to air pollution is only a small possibility. The distribution of CO showed that the overall emissions increased greatly from March to April, and there was an obvious transmission process. In addition, the MODIS AOD in areas close to the national boundary of China is at a high level (>0.6), and the AOD in the southwest of Guangxi province and the southeast of Yunnan Province is above 0.8. Combined with a typical air pollution event in southern China, the UVAI combined with wind direction and other meteorological data showed that the pollutants were transferred from the Indochinese Peninsula to southern China under the southwest monsoon. The PM_2.5 data from ground-based measurements and backward tracking were used to verify the pollutant source of the pollution event, and it was concluded that the degree of pollution in Yunnan, Guangxi and Guangdong provinces was related to the distance from the Indochinese Peninsula. Results indicate that it is necessary to carry out in-depth research on the impact of cross-border air pollution transport on domestic air quality as soon as possible and to actively cooperate with foreign countries to carry out pollution source research and control.