Brown carbon in winter smogs of Beijing city

The processes of shortwave solar radiation transport in anthropogenically caused smogs are influenced by black carbon absorption. It was shown in [1] that a noticeable contribution to the absorption of radiation by smogs can also be made by “brown carbon” (BrC), which are organic compounds with a broad absorption band in the ultraviolet region of the spectrum. In [2], a new non-photochemical mechanism of winter smog formation was described, which was brought to the attention of researchers in January 2013. 

In this connection, a new task arose to investigate the variability of optical and microphysical characteristics of aerosol in non-photochemical smogs, variations of black carbon and brown carbon content in winter smogs of Beijing.

In this paper, the variability of particle size distribution function, aerosol optical attenuation thickness, imaginary part of refractive index and single scattering albedo in winter smogs of Beijing city were analyzed. The statistical characteristics of variations of aerosol optical characteristics in winter smogs of Beijing were calculated. Statistical relations of brown and black carbon content with aerosol optical thickness were studied.

1.       Gorchakov G.I., Karpov A.V., Gushchin R.A., Datsenko O.I., Semutnikova E.G. Black and brown carbon and selective absorption of radiation by smoke aerosol during mass forest fires in Alaska in 2019 and in Canada in 2023 // Atmospheric and Ocean Optics. 2025. V.38, № 1. P. 32-38. [In Russian]

2.       Pronchev G. B., Ermakov A. N. Mechanism of non-photochemical formation and estimation of the rate of sulfate accumulation in the atmospheric haze // Atmospheric and Ocean Optics. 2025. V. 38, № 3. P. 178-184. [In Russian]