Global Health Impacts of International and Domestic Shipping

Abstract:

Maritime shipping emits a large amount of air pollutants that adversely affect public health. Emissions from domestic and international shipping activities are governed under separated regulatory systems. However, previous studies have not differentiated the air pollution-related health impacts of international shipping from domestic shipping.

We conduct an integrated analysis of global ship emissions and their PM_2.5-related health impacts, in which we differentiate the contributions from international and domestic shipping. We first create bottom-up global ship emission inventories based on ship activity records from the Automatic Identification System (AIS). We then use the GEOS-Chem atmospheric chemistry and transport model to compute pollutant concentrations and apply the Global Exposure Mortality Model for estimating health burdens attributable to outdoor PM_2.5 exposure. We also examine the impact of three control policies, including the 0.5% Sulphur Cap entering into force in 2020, post-2020 0.1% Sulphur Cap, and post-2020 Tier III NO_x Standard.

We find that approximately 93,000 premature deaths were associated with PM_2.5 exposure due to maritime shipping in 2015, of which 82% were associated with international shipping activities and 18% by domestic shipping. Although health burdens of ship emissions are dominated globally by international shipping, 30% of shipping-related deaths in China and Japan come from domestic activities. We predict that the 0.5% Sulphur Cap will result in about 30,000 avoided deaths per year. For the two post-2020 control policies, Tier III NOx Standard has larger margin to mitigate health burdens attributable to shipping than the 0.1% Sulphur Cap, reducing PM_2.5-related premature deaths by around 33,000 and 5,000, respectively.