To provide insight into the production of ozone (O3) over the water of Hong Kong (HK), we organized sixteen cruise campaigns between August 2020 and July 2021 to measure O3, nitrogen oxides (NOx), carbon monoxide (CO), and volatile organic compounds (VOCs). Ten westbound, four eastbound and two southbound campaigns were conducted to investigate the characteristics of air pollutants over the Pearl River Estuary, Mirs Bay and Lamma Island anchorage, respectively. Based on cruise observations, this study examines the mixing ratios, reactivities and possible sources of VOCs. Alkanes, alkenes, aromatics, alkynes, halocarbons and alkyl nitrates were measured at a mean concentration of 8.94±5.64 ppbv, 1.18±1.09 ppbv, 1.90±1.48 ppbv, 1.05±0.63 ppbv 3.82±1.23 and 0.09±0.04 ppbv. According to sou...[ Read more ]

To provide insight into the production of ozone (O3) over the water of Hong Kong (HK), we organized sixteen cruise campaigns between August 2020 and July 2021 to measure O3, nitrogen oxides (NOx), carbon monoxide (CO), and volatile organic compounds (VOCs). Ten westbound, four eastbound and two southbound campaigns were conducted to investigate the characteristics of air pollutants over the Pearl River Estuary, Mirs Bay and Lamma Island anchorage, respectively. Based on cruise observations, this study examines the mixing ratios, reactivities and possible sources of VOCs. Alkanes, alkenes, aromatics, alkynes, halocarbons and alkyl nitrates were measured at a mean concentration of 8.94±5.64 ppbv, 1.18±1.09 ppbv, 1.90±1.48 ppbv, 1.05±0.63 ppbv 3.82±1.23 and 0.09±0.04 ppbv. According to source appointment results from positive matrix factorization (PMF) analysis, ship emissions accounted for an average of 15.6% of total VOCs. In addition, liquefied petroleum gas (LPG) usage (24.9%), biomass burning (19.4%), gasoline evaporation (16.2%), solvent usage (13.8%) and aged air mass (9.1%) were recognized. In general, the VOC sources over Hong Kong waters differ from previous studies conducted in the urban and suburban regions of PRD. This study suggests that differentiated control strategies are necessary to control ozone pollution in the PRD region as a whole.