Quantifying evolution of soot mixing state from transboundary transport of biomass burning emissions

Incomplete combustion of fossil fuels and biomass burning emit large amounts of soot particles into the troposphere. The condensation process is considered to influence the size (D_p) and mixing state of soot particles, which affects their solar absorption efficiency and lifetimes. However, quantifying aging evolution of soot remains hampered in the real world because of complicated sources and observation technologies.

Figure 1. Schematic illustration, indicating that aged soot particles in southeastern Tibet came from biomass burning in South Asia.

In the Himalayas, Chen et al. (2023) isolated soot sourced from transboundary transport of biomass burning and revealed soot aging mechanisms through microscopic observations. Most of coated soot particles stabilized one soot core under D_p < 400 nm, but 34.8% of them contained multi-soot cores (n_soot ≥ 2) and n_soot increased 3–9 times with increasing D_p. Chen et al. (2023) established the soot mixing models to quantify transformation from condensation- to coagulation-dominant regime at D_p ≈ 400 nm. Studies provide essential references for adopting mixing rules and quantifying the optical absorption of soot in atmospheric models.

This study from Prof. Weijun Li’s group has been published at iScience (https://doi.org/10.1016/ j.isci.2023.108125). This work was funded by the National Natural Science Foundation of China (42075096; 42277080), Zhejiang Provincial Basic Commonweal Project (Grant No. LGC22B050009), and Fundamental Research Funds for the Central Universities (No. K20220232).

For Details: Chen, X., Ye, C., Wang, Y., Wu, Z., Zhu, T., Zhang, F., Ding, X., Shi, Z., Zheng, Z., and Li, W. (2023). Quantifying evolution of soot mixing state from transboundary transport of biomass burning emissions. iScience 26, 108125. 10.1016/j.isci.2023.108125.