| Title: | Development of an enhanced method for atmospheric carbonyls and characterizing their roles in photochemistry in subtropical Hong Kong |
| Author(s): | Xu Y; Feng X; Chen Y; Zheng P; Hui L; Chen Y; Yu JZ; Wang Z; |
| Address: | "Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Hong Kong, China. Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Hong Kong, China; Department of Chemistry, The Hong Kong University of Science and Technology, Hong Kong, China. Division of Environment and Sustainability, The Hong Kong University of Science and Technology, Hong Kong, China. Electronic address: z.wang@ust.hk" |
| DOI: | 10.1016/j.scitotenv.2023.165135 |
| ISSN/ISBN: | 1879-1026 (Electronic) 0048-9697 (Linking) |
| Abstract: | "Carbonyl compounds are ubiquitous and play vital roles in tropospheric photochemistry and oxidation capacity, particularly affecting radical cycling and ozone formation. An enhanced method based on ultra-high-performance liquid chromatography and electrospray ionization tandem mass spectrometry was developed to simultaneously quantify 47 carbonyl compounds with carbon (C) numbers from 1 to 13. Applying this new method to samples collected at ground and ship-borne field campaigns, we investigated the abundance, characteristic distribution, and photochemical activity of carbonyl species in the coastal atmosphere of Hong Kong. The total concentration of detected carbonyls ranged from 9.1 to 32.7 ppbv and exhibited distinct spatial variability. In addition to the usual abundant carbonyl species (formaldehyde, acetaldehyde, and acetone), aliphatic saturated aldehydes with C >/= 5 (particularly hexaldehyde and nonanaldehyde), and di?ª╡carbonyls, exhibit significant abundance and photochemical reactivity in the coastal site and on the sea. The measured carbonyls could contribute to an estimated peroxyl radical formation rate of 1.88-8.43 ppb/h via OH oxidation and photolysis, greatly enhancing oxidation capacity and radical cycling. The ozone formation potential (OFP) estimated from the maximum incremental reactivity (MIR) was dominated (69 %-82 %) by formaldehyde and acetaldehyde, with significant contribution (4 %-13 %) from di?ª╡carbonyls. Furthermore, another dozens of long-chain carbonyls without MIR values, which were typically below detection or not included in the conventional analytical method, would increase the ozone formation rate by an additional 2 %-33 %. Additionally, the glyoxal, methylglyoxal, benzaldehyde and other alpha, beta-unsaturated aldehydes also exhibited considerable contribution to secondary organic aerosol (SOA) formation potential. This study highlights the importance of various reactive carbonyls in the atmospheric chemistry of urban and coastal regions. The newly developed method can effectively characterize more carbonyl compounds and advance our understanding of their roles in photochemical air pollution" |
| Keywords: | Air pollution Carbonyl compounds New analytical method Oxygenated volatile organic compounds Photochemical reactivity Uhplc-esi-ms/ms; |
| Notes: | "PubMed-not-MEDLINEXu, Yang Feng, Xin Chen, Yao Zheng, Penggang Hui, Lirong Chen, Yi Yu, Jian Zhen Wang, Zhe eng Netherlands 2023/06/29 Sci Total Environ. 2023 Oct 20; 896:165135. doi: 10.1016/j.scitotenv.2023.165135. Epub 2023 Jun 26" |
