Dense ship traffic, port operations and port related land transportation are the cause of emissions in harbour areas. Emissions to air are the most important factors that increase the greenhouse effect and climate change. The main source is exhaust gas from combustion engines that are used in marine and road traffic and partially in train traffic and working machines in the port area. In addition, emissions to air can cause health problems in the respiratory system and the eyes. In some cases, long-term exposure can cause cancer, e.g. leukaemia and cardiopulmonary mortality. It has been estimated that shipping causes approximately 60,000 deaths annually on a global scale. In Finland, emissions to air are controlled and measured trough environmental permits and environmental impact assessment procedures. Different regulations for SOx and NOx will decrease emissions; nevertheless, there is no revolutionary or suitable global technique to decrease emissions that would suit all ports.