Contribution of ship emissions to the fine particulate in the community near an international port in Hong Kong

Fine particulates from ship exhaust are proved to be harmful to human health. To better understand the impact of ship emissions on the particulate matter (PM) level of port-side residential areas, fine particulates (PM2.5) were collected near Kwai Chung and Tsing Yi Container Terminals (KTCT) in Hong Kong during August 2009 to March 2010. The average PM2.5 concentration was 30.5 μg/m3. The contribution of ship emissions on fine particulates near the container port was demonstrated by source apportionment. By positive matrix factorization (PMF) analysis, eight potential sources, i.e., residual oil (RO) combustion, marine diesel oil (MDO) combustion, vehicle emission, coal combustion, incineration, crustal and sea-salt, secondary sulfate and secondary nitrate were identified. Among the identified sources, RO combustion and MDO combustion were regarded as ship emissions and accounted for 12% and 7% of PM2.5 respectively. An estimate of 1.8 μg/m3 (6%) of secondary sulfate corresponded to 3.6 μg/m3 of primary fine particulates from RO combustion. Together with primary PM emitted from ships, the total ambient PM2.5 mass associated with ship emissions at the sampling site was 7.6 μg/m3 (25%).