Preprints
https://doi.org/10.5194/egusphere-2025-4785
https://doi.org/10.5194/egusphere-2025-4785
07 Oct 2025
 | 07 Oct 2025
Status: this preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).

Highly time-resolved chemical characteristics and aging process of submicron aerosols over the central Himalayas

Yishen Wang, Yanqing An, Yulong Tan, Kemei Li, Jianzhong Xu, and Shugui Hou

Abstract. Aerosol particles transported from South Asia, especially biomass burning (BB) emission related aerosols during pre-monsoon, have significant climate effect in the Himalayas. The details on complicated physicochemical properties and aging process of aerosols are important for understanding this climate effect. An Aerodyne high-resolution time-of-flight aerosol mass spectrometer co-located with gas analyzers was deployed during 25 April 2022 to 25 May 2022 to study the highly time-resolved chemical characteristics and aging process of submicron aerosols (PM1) on the northern slope of the Himalayas. The 10-min resolution mass concentration of PM1 varied from 0.1 to 12.2 µg m−3 during this study, with an average of 1.7 ± 1.6 µg m−3. Organic aerosols (OA) showed a dominant contribution (46.2 %) to PM1 following by sulfate (20.8 %), BC (19.4 %), ammonium (8.5 %), nitrate (4.8 %) and chloride (0.4 %). Evolution of bulk OA in the f44 vs. f60 space showed clear aging process from less aged BB plumes to highly oxidized state in polluted period. Positive matrix factorization (PMF) on the high-resolution organic mass spectra resolved two oxygenated OA (OOA) factors, i.e., a less-oxidized OOA influenced by biomass burning (OOA-BB) and a more-oxidized OOA (MO-OOA). We performed a case study to explore the OOA formation mechanism during long-range transport. The results indicated aqueous‐phase process and photochemical reaction together elevated OOA concentrations and ageing processing, consistent with secondary inorganic aerosol production. This study underscores the significant occurrence of BB aerosols in Himalayas and provides insights into the oxidative processing in this remote region.

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this paper. While Copernicus Publications makes every effort to include appropriate place names, the final responsibility lies with the authors. Views expressed in the text are those of the authors and do not necessarily reflect the views of the publisher.
Share
Yishen Wang, Yanqing An, Yulong Tan, Kemei Li, Jianzhong Xu, and Shugui Hou

Status: open (until 18 Nov 2025)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
Yishen Wang, Yanqing An, Yulong Tan, Kemei Li, Jianzhong Xu, and Shugui Hou
Yishen Wang, Yanqing An, Yulong Tan, Kemei Li, Jianzhong Xu, and Shugui Hou

Viewed

Total article views: 41 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
34 6 1 41 2 0 0
  • HTML: 34
  • PDF: 6
  • XML: 1
  • Total: 41
  • Supplement: 2
  • BibTeX: 0
  • EndNote: 0
Views and downloads (calculated since 07 Oct 2025)
Cumulative views and downloads (calculated since 07 Oct 2025)

Viewed (geographical distribution)

Total article views: 39 (including HTML, PDF, and XML) Thereof 39 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 08 Oct 2025
Download
Short summary
We studied air pollution transported from South Asia to the Himalayas during the pre-monsoon season. Using real-time instruments, we measured airborne particles and trace gases on the northern slope of the mountains. We found that burning biomass was a major source of these particles, which changed chemically as they travelled long distances. These changes were affected by photochemical and cloud processes, with important consequences for the regional climate and melting of glaciers.
Share