Limiting engine emissions through technology
Emissions from aircraft engines that affect air quality are nitrogen oxides (NOx), carbon monoxide (CO), sulphur oxides (SOx), unburned hydrocarbons (HC), smoke and particulate matter (PM). Improved engine designs have gradually reduced the emissions of NOx and CO and have almost completely eliminated emissions of unburned hydrocarbons (HC) and smoke.
Certification standards for engine emissions
Aircraft engines have to meet mandatory certification requirements established by ICAO’s Committee on Aviation Environmental Protection. ICAO has adopted certification standards for NOx, CO, HC and smoke. A certification requirement for non-volatile particulate matter is under development.
A comprehensive approach
Aircraft are not the only or even the main source of local emissions around airports. Their contribution is relatively small compared to emissions from road traffic and other ground activities. Therefore, all sources must be considered in order to reduce total emissions. Measures should include, for instance, clean and efficient surface access to airports.