Maritime transport has always been the primary mode of transport for economic trade between countries, providing convenience and benefits to both parties. Countries had paid increasing attention to air pollutants generated by ships near ports in recent years because the health risks posed by air pollutants produced by ships to the environment around ports and to populations have increased as air pollutant emissions have enhanced. The IMO, for its part, has established a number of laws and regulations concerning the emission of air pollutants from ships, such as the emission control area established by each country and policies such as vessel speed reduction operation. Air pollution regulations for Korea's five major ports are also tightening.
As a result, the air pollution emissions and environmental costs of ships, including merchant ships and fishing vessels, cruising or moored in the designated study area in the port of Busan during June 2019 were calculated using the bottom-up method, which has a higher accuracy than the top-down method, using AIS data carried on the ships. CO₂, NOX, SOX, CO, and PM are the air pollutants calculated.
According to the calculation results, container ships had the highest air pollutant emissions in the nearby area of the port, with emissions of 94,900 tons; tankers came in second, with emissions of 77,600 tons. They account for 35.6 percent of total emissions and 29.1 percent of total emissions, respectively. In addition, the deadweight tonnage of ships can be obtained through AIS data, and the air pollutant emissions per dwt ton of ships can be calculated by dividing the total emissions of different ship types by the total tonnage of each type of ships, and the results show that passenger ships were the ship types with the highest emissions per dwt ton of ships. Therefore, if the number of passenger ships in and out of the Busan port area increases, the air pollution emissions will also increase.
CO₂ was the most emitted atmospheric pollutant, accounting for 257,200 tons of emissions; NOX came in second, accounting for 6,200 tons of emissions. It is well known that CO₂ is one of the main sources of the greenhouse effect, and the world has been working to combat it in recent years. In addition, since NOX and SOX have a significant impact on the environment and human health, policies to reduce these air pollutants are gradually becoming formalized. In terms of environmental costs, although CO₂ has the highest emissions, the corresponding environmental costs were not the highest because CO₂ has the smallest environmental cost coefficient; while PM has the largest environmental cost coefficient and nearly half the environmental costs of CO₂, although the emissions are similar to those of CO. Therefore, PM emissions need to be concerned.