Emission Control Area

Emission Control Areas are designated sea regions where the international rules on air pollution from ships are tightened beyond the global standard, because these waters are close to populated coastlines and sensitive environments where ship exhaust has a greater impact on human health and ecosystems. Established under MARPOL Annex VI, an ECA can apply stricter limits on sulphur oxides, on nitrogen oxides, or on both, and ships entering one must comply with the stricter regime for as long as they are inside it.

The sulphur requirement is the most widely felt. While the global cap limits the sulphur content of marine fuel to 0.50 percent, inside a sulphur ECA the limit is far lower, at 0.10 percent. Ships therefore either switch to a compliant low-sulphur distillate fuel before entering the area, carefully logging the changeover, or use an exhaust gas cleaning system (a scrubber) to remove the sulphur oxides from their exhaust so they can continue burning higher-sulphur fuel. In nitrogen-oxide ECAs, newly built ships must meet the stringent Tier III standard, generally requiring technology such as selective catalytic reduction or exhaust gas recirculation, or the use of a clean fuel such as LNG.

The principal ECAs include the Baltic Sea, the North Sea and English Channel, the North American area covering much of the coast of the United States and Canada, and the United States Caribbean area around Puerto Rico and the US Virgin Islands, with further areas being added over time. For operators, ECAs shape voyage planning and fuel management, since the ship must carry and manage more than one grade of fuel and switch between them at the right moment, and they have driven investment in scrubbers and cleaner fuels. The ECAs demonstrate the principle of applying the strongest environmental controls where the benefit to people and nature is greatest.