The contribution of ship emissions to particle concentration downwind of a major shipping route

Abstract: Air pollution still poses a serious air quality problem. There are numerous of different sources for air pollution. One of them is ship traffic, which has an effect on human health as well as the climate system. We decided to investigate one of the largest shipping lanes in the North Sea to what extent ships actually contribute to the particle concentrations in inland locations. Both particle number and volume concentrations between 12 and 500 nm in diameter are investigated in a field study in Denmark performed during the first half of 2012. A method has been developed to calculate how ship plumes in the North Sea ship route are transported to the Danish coast line, and to separate the ship plumes from the background. Finally, the particle number and volume contributions from ship traffic were calculated using two different methods which yielded a lower and an upper estimate of the contributions. The method showed that the ships contributed to between 10% - 21% of the particle number concentration and between 3% - 18% for the volume concentration on average. These results show that ships play a role in atmospheric pollution and risk to affect human health in inland locations. The data analysis also showed that the method to calculate contributions from ship traffic can be used in any environment where ship traffic is one of the major sources of air pollution.