Controlling PM by proxy? International regulation of sulphur and PM emissions from shipping

Ships are major contributors to global emissions of air pollutants, with their health and environmental effects being of particular concern in port cities and heavily populated coastal areas adjacent to major shipping lanes. This paper outlines the international regulations tackling two such ship pollutants, being sulphur dioxide (SOx) and particulate matter (PM). In order to understand the current regulatory strategy, it reviews the health and environmental impact of these emissions. The paper then addresses the 2020 sulphur cap on marine fuel imposed by MARPOL and its potential efficacy in reducing the health and environmental effects of shipping emissions. Examples of differing regional and national regulation of sulphur and PM are presented and discussed. The paper questions whether the current international regulatory framework directed at reducing sulphur emissions from ships is an appropriate means to reduce PM emissions