Insight into wet scavenging effects on sulfur and nitrogen containing organic compounds in urban Beijing

Abstract

Sulfur-containing organic compounds (SOCs) and nitrogen-containing organic compounds (NOCs) play critical roles in regulating the physical and chemical properties of organic aerosols (OA), while the understanding of them remains limited. Here, the high-resolution real-time measurements of submicron aerosols were conducted in urban Beijing, mainly to investigate wet scavenging effects on the potential formation and evolution mechanism of OA, especially SOCs and NOCs. OA composition transitioned from being primarily SOCs before wet processes to NOCs after wet processes. Further molecular fragments identification suggested SOCs mainly comprised glycolic acid sulfate formed by aqueous-phase processing during the entire observation, and aromatic- and monoterpene-derived SOCs formed by photochemical processing before snowfall. NOCs species were diverse and dominated by highly oxidized amides and amino acids mainly produced by photochemical processing. This study provided an in-depth insight into the potential formation and evolution pathways of SOCs and NOCs in OA in the urban atmosphere.