Atmospheric impact of ship traffic in four Adriatic-Ionian port-cities: Comparison and harmonization of different approaches

Shipping is a growing transport sector representing a relevant share of atmospheric pollutant
emissions at global scale. In the Mediterranean Sea, shipping affects air quality of
coastal urban areas with potential hazardous effects on both human health and climate.
The high number of different approaches for investigating this aspect limits the comparability
of results. Furthermore, limited information regarding the inter-annual trends of
shipping impacts is available. In this work, an approach integrating emission inventory,
numerical modelling (WRF-CAMx modelling system), and experimental measurements
at high and low temporal resolution is used to investigate air quality shipping impact in
the Adriatic/Ionian area focusing on four port-cities: Brindisi and Venice (Italy), Patras
(Greece), and Rijeka (Croatia). Results showed shipping emissions of particulate matter
(PM) and NOx comparable to road traffic emissions at all port-cities, with larger contributions
to local SO2 emissions. Contributions to PM2.5 ranged between 0.5% (Rijeka) and 7.4%
(Brindisi), those to PM10 were between 0.3% (Rijeka) and 5.8% (Brindisi). Contributions to
particle number concentration (PNC) showed an impact 2-4 times larger with respect to
that on mass concentrations. Shipping impact on gaseous pollutants are larger than those
to PM. The contribution to total polycyclic aromatic hydrocarbon (PAHs) concentrations
was 82% in Venice and 56% in Brindisi, with a different partition gas-particle because of different
meteorological conditions. The inter-annual trends analysis showed the primary
contribution to PM concentrations decreasing, due to the implementation of the European legislation on the use of low-sulphur content fuels. This effect was not present on other pollutants like PAHs.