Characteristics of marine shipping emissions at berth: profiles for PM and VOCs

Abstract. Emissions from ships at berth played an important role in the exposure of atmospheric pollutants to high density population in port areas, but these emissions were not understood very well. In this study, volatile organic compounds (VOCs) and particle emissions from 20 container ships at berth were sampled and analyzed during the fuel switch period at Jingtang Port in Hebei Province, China. VOCs and particles were analyzed by gas chromatography-mass spectrometer (GC-MS) and the Single Particle Aerosol Mass Spectrometer (SPAMS), respectively. VOCs analysis showed that alkanes and aromatics, especially benzene, toluene and heavier compounds e.g. n-heptane, n-octane, n-nonane, dominated the total identified species. Secondary organic aerosol yields and ozone forming potential were 0.017 ± 0.007 g SOA/g VOCs and 2.63 ± 0.37 g O3/g VOCs, respectively. Both positive and negative ion mass spectra from individual ship were derived and intensity of specific ions could be quantified. Results showed that element carbon (35.74 %), element carbon-organic carbon mixture (33.95 %) and Na-rich particles (21.12 %) were major classes with a total number ratio of 90.7 %. Particles from ship auxiliary engines were in a size range of 0.2 to 2.5 μm, with a peak occurring at around 0.4 μm. The issue of vanadium as tracer element was discussed that V was not a proper tracer when using low sulfur content diesel oil. The average percentage of sulfate particles from shipping emissions before and after switching to marine diesel oil were 23.82 % and 23.61 % respectively. The total results provide robust evidences in port area air quality assessment and source apportionment.