TY  - JOUR
AU  - Chen, Yijing
AU  - Xia, Men
AU  - Zhang, Jinghui
AU  - Tsiligiannis, Epameinondas
AU  - Wu, Cheng
AU  - Yan, Chao
AU  - Cai, Runlong
AU  - Zheng, Guangjie
AU  - Li, Yuyang
AU  - Guo, Junchen
AU  - An, Zhaojin
AU  - Li, Yiran
AU  - Zhao, Xinyan
AU  - Qu, Qipeng
AU  - Hua, Chenjie
AU  - Wang, Zongcheng
AU  - Wang, Shuxiao
AU  - Liu, Yongchun
AU  - Cao, Lina
AU  - He, Kebin
AU  - Kulmala, Markku
AU  - Hallquist, Mattias
AU  - Wang, Tao
AU  - Worsnop, Douglas
AU  - Jiang, Jingkun
PY  - 2025
DA  - 2025//
TI  - Chloramine chemistry as a missing link in atmospheric chlorine cycling
JO  - Science Advances
SP  - eadv4298
VL  - 11
IS  - 44
AB  - Chlorine radicals (Cl·) profoundly affect atmospheric oxidation capacity. Chloramines, especially trichloramine, are emerging precursors of Cl·. However, their sources and roles in the atmosphere remain elusive. This study presents field evidence of primary emissions and explicit secondary production pathways of atmospheric trichloramine in Beijing, supplemented by observations from New Delhi and reanalysis of measurements in Toronto. We demonstrate that the sequential chlorination reactions initiated by molecular chlorine and ammonia in atmospheric aerosols are a major source of trichloramine. The trichloramine produced in aerosols is a source of gaseous trichloramine and serves as an intermediate during the conversion from molecular chlorine to Cl·, while direct trichloramine emissions constitute a previously overlooked source of Cl·. Overall, chloramine chemistry alters the Cl· production mechanism and represents a crucial missing pathway to Cl· worldwide. Chloramines from emissions and secondary production represent an overlooked component in atmospheric chlorine chemistry.
UR  - https://www.science.org/doi/abs/10.1126/sciadv.adv4298
ID  - Chen2025
ER  -