Abstract
Five C 1-C 4 alkyl nitrates (RONO 2) were measured at a coastal site in Hong Kong in four selected months of 2011 and 2012. The total mixing ratios of C 1-C 4 RONO 2 (Σ 5RONO 2) ranged from 15.4 to 143.7 pptv with an average of 65.9 ± 33.0 pptv. C 3-C 4 RONO 2 (2-butyl nitrate and 2-propyl nitrate) were the most abundant RONO 2 during the entire sampling period. The mixing ratios of C 3-C 4 RONO 2 were higher in winter than those in summer, while the ones of methyl nitrate (MeONO 2) were higher in summer than those in winter. Source analysis suggests that C 2-C 4 RONO 2 were mainly derived from photochemical formation along with biomass burning (58.3–71.6%), while ocean was a major contributor to MeONO 2 (53.8%) during the whole sampling period. The photochemical evolution of C 2-C 4 RONO 2 was investigated, and found to be dominantly produced by the parent hydrocarbon oxidation. The notable enrichment of MeONO 2 over C 3-C 4 RONO 2 was observed in a summer episode when the air masses originating from the South China Sea (SCS) and MeONO 2 was dominantly derived from oceanic emissions. In order to improve the accuracy of ozone (O 3) prediction in coastal environment, the relative contribution of RONO 2 from oceanic emissions versus photochemical formation and their coupling effects on O 3 production should be taken into account in future studies.
Original language | English |
---|---|
Pages (from-to) | 275-284 |
Number of pages | 10 |
Journal | Chemosphere |
Volume | 194 |
DOIs | |
Publication status | Published - 1 Mar 2018 |
Keywords
- Alkyl nitrates
- Marine emissions
- Ozone
- Photochemical production
- Seasonality
ASJC Scopus subject areas
- General Chemistry
- Environmental Chemistry