Year‐Long Real‐Time Measurements of Fine Particles in the Northeastern Tibetan Plateau: Insights Into Seasonal Variation and Chemical Processes

Abstract Long‐term in situ aerosol observations are scarce on the Tibetan Plateau (TP) due to its harsh natural environment, limiting our ability to evaluate its climate effect at this critical region. This study presents the first year‐long real‐time observations of non‐refractory fine particulate matter (NR‐PM 2.5 ) conducted in the northeastern TP, to explore the seasonal variation in aerosol characteristics. The average NR‐PM 2.5 concentration is 4.7 ± 5.3 μg m −3 with a dominant contribution of organics. Our findings reveal distinct seasonal variations in NR‐PM 2.5 mass loading and chemical composition, regulated by the alternation of the Asian summer monsoon and westerlies there, as well as the balance between the wet scavenging and dry deposition in each season. Specifically, enhanced aqueous‐phase chemical process during summer was observed contributing to stronger oxidation processes of organic aerosol with different oxidation pathways. These findings provided an in‐depth insight into the linkage between climate systems and atmospheric aerosols in the TP.