ACP - recent papers

1. Mechanistic insights into chloroacetic acid production from atmospheric multiphase volatile organic compound–chlorine chemistry
   Mechanistic insights into chloroacetic acid production from atmospheric multiphase volatile organic compound–chlorine chemistry Mingxue Li, Men Xia, Chunshui Lin, Yifan Jiang, Weihang Sun, Yurun Wang, Yingnan Zhang, Maoxia He, and Tao Wang Atmos. Chem. Phys., 25, 3753–3764, https://doi.org10.5194/acp-25-3753-2025, 2025 Our field campaigns observed a strong diel pattern of chloroacetic acid as well as a strong correlation between its level and that of reactive chlorine species at a coastal site. Using quantum chemical calculations and box model simulation with an updated Master Chemical Mechanism, we found that the formation pathway of chloroacetic acid involved multiphase processes. Our study enhances understanding of atmospheric organic chlorine chemistry and emphasizes the importance of multiphase reactions.
2. Formation of highly absorptive secondary brown carbon through nighttime multiphase chemistry of biomass burning emissions
   Formation of highly absorptive secondary brown carbon through nighttime multiphase chemistry of biomass burning emissions Ye Kuang, Biao Luo, Shan Huang, Junwen Liu, Weiwei Hu, Yuwen Peng, Duohong Chen, Dingli Yue, Wanyun Xu, Bin Yuan, and Min Shao Atmos. Chem. Phys., 25, 3737–3752, https://doi.org10.5194/acp-25-3737-2025, 2025 This research reveals the potential importance of nighttime NO3 radical chemistry and aerosol water in the rapid formation of secondary brown carbon from diluted biomass burning emissions. The findings enhance our understanding of nighttime biomass burning evolution and its implications for climate and regional air quality, especially regarding interactions with background aerosol water and water-rich fogs and clouds.
3. In situ vertical observations of the layered structure of air pollution in a continental high-latitude urban boundary layer during winter
   In situ vertical observations of the layered structure of air pollution in a continental high-latitude urban boundary layer during winter Roman Pohorsky, Andrea Baccarini, Natalie Brett, Brice Barret, Slimane Bekki, Gianluca Pappaccogli, Elsa Dieudonné, Brice Temime-Roussel, Barbara D'Anna, Meeta Cesler-Maloney, Antonio Donateo, Stefano Decesari, Kathy S. Law, William R. Simpson, Javier Fochesatto, Steve R. Arnold, and Julia Schmale Atmos. Chem. Phys., 25, 3687–3715, https://doi.org10.5194/acp-25-3687-2025, 2025 This study presents an analysis of vertical measurements of pollution in an Alaskan city during winter. It investigates the relationship between the atmospheric structure and the layering of aerosols and trace gases. Results indicate an overall very shallow surface mixing layer. The height of this layer is strongly influenced by a local shallow wind. The study also provides information on the pollution chemical composition at different altitudes, including pollution signatures from power plants.
4. Did the 2022 Hunga eruption impact the noctilucent cloud season in 2023/24 and 2024?
   Did the 2022 Hunga eruption impact the noctilucent cloud season in 2023/24 and 2024? Sandra Wallis, Matthew DeLand, and Christian von Savigny Atmos. Chem. Phys., 25, 3635–3645, https://doi.org10.5194/acp-25-3635-2025, 2025 The 2022 Hunga Tonga – Hunga Ha'apai eruption emitted about 150 Tg H2O that partly reached the upper polar Southern Hemisphere mesosphere in the beginning of 2024. Noctilucent clouds (NLCs) did not show a clear perturbation in their occurrence frequency, but the slight increase from mid-January to February could potentially have been caused by the additional H2O. It needed 2 years to reach the summer polar mesopause region, analogous to the 1883 Krakatoa eruption that is argued to have caused the first sightings of NLCs.
5. Measurement report: Optical and structural properties of atmospheric water-soluble organic carbon in China – insights from multi-site spectroscopic measurements
   Measurement report: Optical and structural properties of atmospheric water-soluble organic carbon in China – insights from multi-site spectroscopic measurements Haibiao Chen, Caiqing Yan, Liubin Huang, Lin Du, Yang Yue, Xinfeng Wang, Qingcai Chen, Mingjie Xie, Junwen Liu, Fengwen Wang, Shuhong Fang, Qiaoyun Yang, Hongya Niu, Mei Zheng, Yan Wu, and Likun Xue Atmos. Chem. Phys., 25, 3647–3667, https://doi.org10.5194/acp-25-3647-2025, 2025 A comprehensive understanding of the optical properties of brown carbon (BrC) is essential to accurately assess its climatic effects. Based on multi-site spectroscopic measurements, this study demonstrated the significant spatial heterogeneity in the optical and structural properties of water-soluble organic carbon (WSOC) in different regions of China and revealed factors affecting WSOC light absorption and the relationship between fluorophores and light absorption of WSOC.