Indeed, emissions from aircraft and other emission sources at an airport have an effect on the local air quality (LAQ): in particular, emissions of nitrogen oxides (NOx), volatile organic compounds (VOCs), carbon monoxide (CO) and particulate matter (PM) are the most important contributors on LAQ concerns. However, the airport is not the only source of emissions. Usually airports are surrounded by road networks and supplied by power stations and other industrial facilities. The airport is therefore not the only, and often not even the major source, responsible for all the air pollution measured in the area. The pragmatic solution to understanding the contribution of an airport to the measured air quality at any point around it, is through modelling.

Combining the Emissions inventory with dispersion models can be used to assess the current or the forecast LAQ for planned projects.

Knowing what are the critical pollutants and where the concentration is close or higher than regulated limits, is essential to better understand the problem at its source.

New infrastructure projects such as new runways or Terminals can be assessed fr their impact as the geographical distribution of the sources and the amounts will clearly change, as will non airport sources, in particular road traffic, which may have some dependency relationship with any growth of the airport.