The impact of ship emissions on air quality and human health in the Gothenburg area – Part 1: 2012 emissions

oleh: L. Tang, L. Tang, M. O. P. Ramacher, J. Moldanová, V. Matthias, M. Karl, L. Johansson, J.-P. Jalkanen, K. Yaramenka, A. Aulinger, M. Gustafsson

Format: Article
Diterbitkan: Copernicus Publications 2020-06-01

Deskripsi

<p>Ship emissions in and around ports are of interest for urban air quality management in many harbour cities. We investigated the impact of regional and local ship emissions on urban air quality for 2012 conditions in the city of Gothenburg, Sweden, the largest cargo port in Scandinavia. In order to assess the effects of ship emissions, a coupled regional- and local-scale model system has been set up using ship emissions in the Baltic Sea and the North Sea as well as in and around the port of Gothenburg. Ship emissions were calculated with the Ship Traffic Emission Assessment Model (STEAM), taking into account individual vessel characteristics and vessel activity data. The calculated contributions from local and regional shipping to local air pollution in Gothenburg were found to be substantial, especially in areas around the city ports. The relative contribution from local shipping to annual mean <span class="inline-formula">NO<sub>2</sub></span> concentrations was 14&thinsp;% as the model domain average, while the relative contribution from regional shipping in the North Sea and the Baltic Sea was 26&thinsp;%. In an area close to the city terminals, the contribution of <span class="inline-formula">NO<sub>2</sub></span> from local shipping (33&thinsp;%) was higher than that of road traffic (28&thinsp;%), which indicates the importance of controlling local shipping emissions. Local shipping emissions of <span class="inline-formula">NO<sub><i>x</i></sub></span> led to a decrease in the summer mean <span class="inline-formula">O<sub>3</sub></span> levels in the city by 0.5&thinsp;ppb (<span class="inline-formula">∼2</span>&thinsp;%) on average. Regional shipping led to a slight increase in <span class="inline-formula">O<sub>3</sub></span> concentrations; however, the overall effect of regional and the local shipping together was a small decrease in the summer mean <span class="inline-formula">O<sub>3</sub></span> concentrations in the city. In addition, volatile organic compound (VOC) emissions from local shipping compensate up to 4&thinsp;ppb of the decrease in summer <span class="inline-formula">O<sub>3</sub></span> concentrations due to the NO titration effect. For particulate matter with a median aerodynamic diameter less than or equal to 2.5&thinsp;<span class="inline-formula">µ</span>m (PM<span class="inline-formula"><sub>2.5</sub></span>), local ship emissions contributed only 3&thinsp;% to the annual mean in the model domain, while regional shipping under 2012 conditions was a larger contributor, with an annual mean contribution of 11&thinsp;% of the city domain average.</p> <p>Based on the modelled local and regional shipping contributions, the health effects of PM<span class="inline-formula"><sub>2.5</sub></span>, <span class="inline-formula">NO<sub>2</sub></span> and ozone were assessed using the ALPHA-RiskPoll (ARP) model. An effect of the shipping-associated PM<span class="inline-formula"><sub>2.5</sub></span> exposure in the modelled area was a mean decrease in the life expectancy by 0.015 years per person. The relative contribution of local shipping to the impact of total PM<span class="inline-formula"><sub>2.5</sub></span> was 2.2&thinsp;%, which can be compared to the 5.3&thinsp;% contribution from local road traffic. The relative contribution of the regional shipping was 10.3&thinsp;%. The mortalities due to the exposure to <span class="inline-formula">NO<sub>2</sub></span> associated with shipping were calculated to be 2.6 premature deaths&thinsp;yr<span class="inline-formula"><sup>−1</sup></span>. The relative contribution of local and regional shipping to the total exposure to <span class="inline-formula">NO<sub>2</sub></span> in the reference simulation was 14&thinsp;% and 21&thinsp;%, respectively. The shipping-related ozone exposures were due to the NO titration effect leading to a negative number of premature deaths. Our study shows that overall health impacts of regional shipping can be more significant than those of local shipping, emphasizing that abatement policy options on city-scale air pollution require close cooperation across governance levels. Our findings indicate that the strengthened Sulphur Emission Control Areas (SECAs) fuel sulphur limit from 1&thinsp;% to 0.1&thinsp;% in 2015, leading<span id="page7510"/> to a strong decrease in the formation of secondary particulate matter on a regional scale was an important step in improving the air quality in the city.</p>