A Coastal Perspective on Air Quality Modelling

Matthias Karl

Abstract:

Introduction

Air quality in coastal cities is considerably affected by emissions from maritime transport in addition to land-based emissions. Pollutant emissions related to shipping, including particulate matter (PM), nitrogen oxides (NO_x) and sulphur dioxide (SO₂), can have adverse effects on ecosystem health by contributing to acid rain and eutrophication (Karl et al., 2019). Shipping emerges as a major source of ultrafine particle (UFP; diameter below 100 nm) emission and secondary formed aerosols in coastal cities. This presentation highlights various aspects of modelling air quality and exposure in coastal regions.

Methodology and Results

Impacts of ship emissions are assessed using a regional-to-local chemistry transport model chain with the EPISODE-CityChem model for the urban scale. Emissions from ocean-going ships are calculated using detailed emission models with ship positions based on data from the Automatic Identification System (AIS). The model chain is applied to simulate air quality concentrations and exposures in several European coastal cities, with more advanced modelling of secondary aerosol and UFP formation in Marseille (Karl et al., 2023), Athens and Hamburg. Local shipping significantly contributes to the UFP and NO_x exposure in port environments and nearby residential areas but less to urban PM levels.

Conclusions

Modelling the fate of particles emitted from shipping demonstrates the much higher significance of UFP exposure compared to PM exposure, especially near the source of emissions. To assess health impacts of ship‐emitted particles with air quality models, it is crucial to include not just mass-based emission but also particle number and size distribution.

References

Karl, M.; Bieser, J.; Geyer, B.; Matthias, V.; Jalkanen, J.-P.; Johansson, L.; Fridell, E. Atmos. Chem. Phys. 2019, 19, 1721–1752, https://doi.org/10.5194/acp-19-1721-2019.

Karl, M.; Ramacher, M.O.P.; Oppo, S.; Lanzi, L.; Majamäki, E.; Jalkanen, J.-P.; Lanzafame, G.M.; Temime-Roussel, B.; Le Berre, L.; D’Anna, B. Toxics 2023, 11, 771, https://doi.org/10.3390/toxics11090771.