SHIPping emission's contribution to AIR pollution in urban harbor area – SHIPAIR

Shipping is an essential transport infrastructure, with 80% of our goods undergoing overseas transport. However shipping emissions have impacts on climate change and on air quality, through the emission of gaseous (SO2, NOx, CO2, VOCs…) and particulate (PM) pollutants, particularly important for highly populated coastal areas. Since the 90s, regulations for emissions started to evolve, leading to the current limitations of fuel sulphur content (0.5%) and the application of Tier I - III standards for emissions. It is however likely than further changes need to be implemented to move towards more sustainable practices, particularly in harbors. But it is currently highly challenging to estimate the impact of shipping emissions on urban air quality, due, amongst others, to the transient nature of shipping plumes, the differences between vessels and fuels used, and the lack of understanding of the chemical evolution of the pollutants, which currently hamper accurate modelling of current and future changes. The project SHIPAIR therefore proposes to tackle some of these challenges through an interdisciplinary approach, combining online (& off-line) measurements with real-time shipping data through the automatic identification system and novel modelling approaches.

Two field campaigns will inform not only on the pollutants emitted, but also on their evolution during transport and on their oxidation potential (OP). The first measurement campaign is an intensive (3 weeks) field campaign in the harbor of Dunkirk. Measurements on two locations, one near-field and one close to the urban border, of a comprehensive suite of pollutants (gas and particulates, including on-line metal speciation) will allow a better estimate of their evolution, their influence on the OP and on urban AQ. Furthermore, the deployment of a photochemical flow reactor will allow to assess the secondary aerosol formation potential of the plumes. The second measurement campaign will take place during one year in an urban monitoring site in Marseille, focusing on the deconvolution of different source contributions, in particular to the OP. The deployment for the first time of a novel online instrument to measure OP with a 20-minute time resolution over a long time period (3-4 months), will produce a unique, high resolution data set. The data obtained through these campaigns will be analyzed using state-of-the-art positive matrix factorization (PMF) in order to disentangle different source contributions.

For the local AQ networks (AASQA) involved in SHIPAIR, a major challenge in predicting AQ in port cities, is the unequal access and use of information. To counter this difficulty, the 3 AASQAs will work closely together to harmonize and standardize their modelling approach in close collaboration with the port authorities. The emission inventories used will be enlarged based on literature and ongoing projects. Another difficulty in modelling the AQ of urban center close to harbors, lays in the resolutions of the models and their limited representation of atmospheric processes, affecting notably the accuracy of prediction for ultra-fine particles and the chemical composition of PM. SHIPAIR proposes to develop a new dispersion modelling framework for ship plumes in urban areas, based on a “plume-in-grid” and a “street-in-grid” approach. Furthermore, the model will integrate the treatment for metallic compounds in the SSH-aerosol module, allowing to investigate the contribution of metals to the OP. This new modelling framework will be evaluated against the measurement dataset from the campaigns and the AASQAs.

Finally, SHIPAIR will compare the impact of shipping emissions determined by the different methodologies (PMF and model with and without shipping emission) for different harbors (Dunkirk, Marseille and Le Havre). After validation first runs of scenarios for future trends will be implemented by each AASQA to evaluate the impact of local mitigation strategies.