Contribution of Ship Emission to Volatile Organic Compounds Based on One‐Year Monitoring at a Coastal Site in the Pearl River Delta Region

Abstract

AbstractShip emission impacts ambient air quality, especially in coastal regions, by emitting air pollutants such as fine particles, nitrogen oxides (NOx), and sulfur dioxide (SO2), yet its contributions to volatile organic compounds (VOCs) and the formation of secondary organic aerosol (SOA) and ozone (O3) are much less constrained with the challenge in distinguish ship emission from land diesel emission. In this study, we conducted a 1‐year online measurement of VOCs with a 1‐hr resolution at a coastal site in south China's Pearl River Delta region, which holds three of the world's top 10 container ports. The results revealed that C10–C12 n‐alkanes, as typical diesel‐related emission tracers, were significantly enhanced and strongly related to oceanic air masses. Receptor modeling revealed two diesel‐related sources of land diesel emission and ship emission, which could be differentiated based on their source profiles, seasonal trends and air mass back trajectories. Ship emissions contributed 6.4%, 5.0%, and 13.6% of total VOC mixing ratios, ozone formation potentials (OFPs), and secondary organic aerosol formation potentials (SOAFPs), while these percentages were 3.4%, 14.7%, and 15.9% for land diesel emission, respectively. In particular, in July, ship emissions could contribute 21.7%, 14.6%, and 31.2% of VOCs, OFPs, and SOAFPs, respectively. Our results highlight the important contribution of diesel‐related emission VOCs in forming O3 and SOA in coastal regions, and ship emission is a non‐negligible source of VOCs, particularly after the strict control of land emission sources.