We all know that road traffic is a source of air pollution, but it’s easy to forget that highways are not the only place we can see traffic. Large marine vessels contribute to air pollution in the port cities they visit on their shipping routes.
The sulphur content of the heavy fuel oil used by these ships is much higher than the fuel we use in other types of transportation such as road vehicles. This generates sulphur dioxide (SO2) pollution, which can trigger acute respiratory distress, particularly for individuals with asthma. Large ships operating on heavy fuel oil also release other harmful air pollutants, including fine particulate matter (PM2.5), that can negatively affect our health. Lowering levels of marine vessel pollution can improve ambient air quality, which lets everyone breathe more easily, particularly Canadians living in port cities.
To reduce the impact of marine sector air pollution, Canada, the United States, and France came together to designate a North American Emissions Control Area (ECA), targeting the pollution effects of high-sulphur unrefined heavy fuel oil. Regulations require the use of low-sulphur fuel in Canadian waters within the control area, reducing the maximum acceptable amount of sulphur from 3.5% to 1% in 2012, and finally to 0.1% in 2015.
Health Canada scientist Dr. Angelos Anastasopolos led the team that tracked and measured the impact of these regulations on Canadian air quality. The Health Canada team conducted comprehensive air sampling in Halifax, Nova Scotia – Atlantic Canada’s busiest port. They also collaborated with colleagues at Environment and Climate Change Canada to assess air quality trends in multiple other Canadian port cities before and after the introduction of the regulations, including Vancouver, Victoria, Montreal and Quebec City.
“Findings are good news for port city air quality,” says Dr. Anastasopolos. “Implementation of the low-sulphur marine fuel regulations has led to substantial decreases in overall ambient SO2 levels at all Canadian port cities we examined -- even at ports where ship traffic has increased such as Halifax.”
In fact, scientists found that the low-sulphur fuel regulations led to much lower levels of ambient SO2 air pollution, with hourly concentrations decreasing by an average of 62% across the reviewed port sites. The emissions from the vessels themselves are expected to have been reduced by 90% following the implementation of the standard. Fine particulate matter (also known as PM2.5) was also reduced. In fact, PM2.5 composition in the air changed significantly in the port cities after the regulation were implemented, with a dramatic decrease in sulphate and the heavy metals nickel and vanadium, which are markers of heavy fuel oil combustion. Newly introduced 2020 marine regulations that reduce permissible fuel sulphur from 3.5% to 0.5% for ships sailing in waters outside Emissions Control Areas may bring similar large-scale international benefits to air quality.
“The data we examined make the positive impact of the regulations clear, showing us that these initiatives are meaningful to the health of Canadians living in port cities and providing evidence to support future marine transport policy development,” explains Dr. Anastasopolos.
This research was published in Science of The Total Environment. The findings of this study are being shared with relevant federal government departments, provinces and territories, and the public in port communities, and will contribute to ongoing improvement in air quality for Canadians and the international community.