ACP - recent papers

1. Understanding summertime peroxyacetyl nitrate (PAN) formation and its relation to aerosol pollution: insights from high-resolution measurements and modeling
   Understanding summertime peroxyacetyl nitrate (PAN) formation and its relation to aerosol pollution: insights from high-resolution measurements and modeling Baoye Hu, Naihua Chen, Rui Li, Mingqiang Huang, Jinsheng Chen, Youwei Hong, Lingling Xu, Xiaolong Fan, Mengren Li, Lei Tong, Qiuping Zheng, and Yuxiang Yang Atmos. Chem. Phys., 25, 905–921, https://doi.org10.5194/acp-25-905-2025, 2025 Box modeling with the Master Chemical Mechanism (MCM) was used to explore summertime peroxyacetyl nitrate (PAN) formation and its link to aerosol pollution under high-ozone conditions. The MCM model is effective in the study of PAN photochemical formation and performed better during the clean period than the haze period. Machine learning analysis identified ammonia, nitrate, and fine particulate matter as the top three factors contributing to simulation bias.
2. The role of OCO-3 XCO2 retrievals in estimating global terrestrial net ecosystem exchanges
   The role of OCO-3 XCO2 retrievals in estimating global terrestrial net ecosystem exchanges Xingyu Wang, Fei Jiang, Hengmao Wang, Zhengqi Zhang, Mousong Wu, Jun Wang, Wei He, Weimin Ju, and Jing M. Chen Atmos. Chem. Phys., 25, 867–880, https://doi.org10.5194/acp-25-867-2025, 2025 The role of OCO-3 XCO2 retrievals in estimating global terrestrial carbon fluxes is unclear. We investigate this by assimilating OCO-3 XCO2 retrievals alone and in combination with OCO-2 XCO2. The assimilation of OCO-3 XCO2 alone underestimates global land sinks, mainly at high latitudes, due to the lack of observations beyond 52° S and 52° N, large variations in the number of data, and varying observation times, while the joint assimilation of OCO-2 and OCO-3 XCO2 has the best performance.
3. Measurement report: A comparative analysis of an intensive incursion of fluorescing African dust particles over Puerto Rico and another over Spain
   Measurement report: A comparative analysis of an intensive incursion of fluorescing African dust particles over Puerto Rico and another over Spain Bighnaraj Sarangi, Darrel Baumgardner, Ana Isabel Calvo, Benjamin Bolaños-Rosero, Roberto Fraile, Alberto Rodríguez-Fernández, Delia Fernández-González, Carlos Blanco-Alegre, Cátia Gonçalves, Estela D. Vicente, and Olga L. Mayol-Bracero Atmos. Chem. Phys., 25, 843–865, https://doi.org10.5194/acp-25-843-2025, 2025 Measurements of fluorescing aerosol particle properties have been made during two major African dust events, one over the island of Puerto Rico and the other over the city of León, Spain. The measurements were made with two wideband integrated bioaerosol spectrometers. A significant change in the background aerosol properties, at both locations, is observed when the dust is in the respective regions.
4. The surface tension and cloud condensation nuclei (CCN) activation of sea spray aerosol particles
   The surface tension and cloud condensation nuclei (CCN) activation of sea spray aerosol particles Judith Kleinheins, Nadia Shardt, Ulrike Lohmann, and Claudia Marcolli Atmos. Chem. Phys., 25, 881–903, https://doi.org10.5194/acp-25-881-2025, 2025 We model the cloud condensation nuclei (CCN) activation of sea spray aerosol particles with classical Köhler theory and with a new model approach that takes surface tension lowering into account. We categorize organic compounds into weak, intermediate, and strong surfactants, and we outline for which composition surface tension lowering is important. The results suggest that surface tension lowering allows sea spray aerosol particles in the Aitken mode to be a source of CCN in marine updraughts.
5. Does total column ozone change during a solar eclipse?
   Does total column ozone change during a solar eclipse? Germar H. Bernhard, George T. Janson, Scott Simpson, Raúl R. Cordero, Edgardo I. Sepúlveda Araya, Jose Jorquera, Juan A. Rayas, and Randall N. Lind Atmos. Chem. Phys., 25, 819–841, https://doi.org10.5194/acp-25-819-2025, 2025 Several publications have reported that total column ozone (TCO) may oscillate during solar eclipses, whereas other researchers have not seen evidence of such fluctuations. Here, we try to resolve these contradictions by measuring variations in TCO during three solar eclipses. In all instances, the variability in TCO was within natural variability. We conclude that solar eclipses do not lead to measurable variations in TCO, drawing into question reports of much larger changes found in the past.