Pollutants emitted from typical Chinese vessels: Potential contributions to ozone and secondary organic aerosols

摘要

Pollutants emitted from ships have adverse effects on the atmospheric environment. In this study, the atmospheric impact of gaseous and particulate pollutants emitted in the exhaust of typical ships was estimated based on real-world measurements obtained under conditions of various engine speeds and fuel types. The results showed that PM2.5 emission factors (EFs) ranged between 0.38 +/- 0.01 and 1.05 +/- 0.04 g/kg fuel, and tended to increase with engine speed. The EFs of volatile organic compounds (VOCs; including 57 species), which varied between 63 +/- 4 and 156 +/- 6 mg/kg fuel at different engine speeds, were determined largely via the modified combustion efficiency. The ozone formation potential (OFP), dominated by alkanes and aromatics, was between 0.33 +/- 0.01 and 0.83 +/- 0.05 g O-3/kg fuel. Secondary organic aerosol formation potential (SOAFP), dominated primarily by aromatics, varied between 2.7 +/- 0.1 and 8.7 +/- 0.7 mg SOA/kg fuel. Switching from heavy fuel oil to diesel oil significantly reduced pollutant emissions with the exception of NOx. Reductions in the EFs of VOCs, PM2.5, and total suspended particles were 67%, 42%, and 66%, respectively. The average fuel-mass-based EFs of OFP and SOAFP from ship emissions were similar to 2.3- and similar to 2.6-fold greater than those exhausted from on-road diesel vehicles, respectively, indicating that ship emissions could be an important source for ground-level ozone and organic aerosol formation, particularly in coastal regions. The results suggest that emission abatement technologies should be applied to marine diesel engines and stringent regulations on VOC species, particularly aromatics, should be imposed to improve regional air quality. (C) 2019 Elsevier Ltd. All rights reserved.