Problems

Some large ships keep their engines running when docked to produce electricity. This practice increases gas emissions and reduces air quality. It is therefore necessary to take measures to reduce idling time when the ship is stopped. Cruise ships also emit large amounts of fine particulate matter. In Canada, more stringent standards have been adopted to solve the problem by requiring the use of higher-quality fuel.

Maritime transport produces relatively few greenhouse gases compared to other transport methods. This is due to the large cargo capacity of ships. With a litre of fuel, a ship can carry a tonne of cargo over a distance of 241 km, while a train would only move the cargo 95 km and a truck just 28 km. By consuming less energy, maritime transport cuts CO₂ emissions.

However, many ships are fitted with diesel engines that use heavy fuel oil, which contains high concentrations of sulphur and other impurities. Burning this fuel produces sulphur oxides and fine particulates that are very harmful to humans and the environment. Some engines also emit hazardous nitrogen oxides. These gases contribute to smog and acid rain, and greatly reduce air quality. Their negative impact is especially high in urban ports, where they can affect the health of nearby residents.

Newer ships produce far fewer pollutants because they have more efficient engines that use cleaner fuel.

Air quality can also be affected by port activities during loading and unloading, as fine particles can be carried by the wind. The systems used to carry out these operations are designed to reduce such losses and maintain air quality.

This laker, built in 2016, is part of one of the world's most modern fleets. It is more fuel-efficient and produces fewer greenhouse gases.