Clear sailing toward shipping emissions regulation?
A groundbreaking marine emissions inventory of vessel traffic in Hong Kong, commissioned by the Environmental Protection Department, and presented at a recent conference, helps us to understand the extent of air pollution from vessels in this city.
This is one of the first inventories of its kind in Asia, with similar work being done by government bodies in Shanghai and Taiwan. The Hong Kong study will likely raise awareness about the impact that these emissions can have in port cities.
Collecting data is critical for evidence-based policy-making. From this scientific research, policy makers can develop specific regulation to address emissions from these sources in a targeted and informed way. This regulation should be consistent with international best practices and conventions.
Preliminary findings show the extent and location of these emissions by using an activity-based approach, taking into account factors like the type of vessel activity (cruising, at berth, maneuvering), the emission source (main engine, auxiliary engine, auxiliary boiler) and the engine activity to give an accurate estimation of actual emissions from ships and boats.
The inventory shows that almost 80 percent of sulphur dioxide (SO2) emissions from vessels come from ocean going vessels (OGVs), while 12 percent are attributed to river vessels and 9 percent to local craft. NOx emissions are more evenly distributed amongst these vessel types, with 44 percent from OGVs, 24 percent from river vessels, and 32 percent from local craft.
Of SO2 emissions from OGVs, 79.5 percent come from container vessels, and 9.2 percent come from cruise ships and ferries connecting Hong Kong to Macau as well as Mainland China. Container vessels and cruise ships share similar proportions of NOx emissions (79.4 percent and 11.1 percent respectively).
Finally, the inventory reveals that 30-40 percent of emissions from OGVs happen when the vessels are at berth.
These findings are important because they pinpoint the significance of emissions from vessels, as well as when and where they emit the most. This gives a point of focus to future regulation.
Lots of emissions happen at berth, and given how close terminals are to dense populations in Hong Kong, addressing these emissions in particular is important. At-berth regulation is something that the shipping industry in Hong Kong continues to support through the Fair Winds Charter, the industry-led, voluntary, at-berth fuel switch for OGVs.
It is also important to note that a large proportion of pollution is emitted in major shipping lanes, which surround Hong Kong, so regulating at-berth emissions is just a first step.