Air Quality

Routine airport operations, maintenance and on-site development projects can generate air emissions and GHGs. Understanding how airport activities produce air emissions and GHGs will provide a firm foundation for conversations about air quality on and near your airport.

Air emissions are produced by either mobile or stationary sources:

• Mobile sources emit air pollutants as result of fuel combustion. Common mobile sources associated with airports include aircraft, transportation vehicles (e.g., shuttles and cars), GSE, APUs, and construction equipment.
• Stationary sources emit air pollutants as a product of either fuel combustion from fixed sources or through the evaporation of fuels and chemicals during refueling, storage, and maintenance practices. Examples of stationary sources at airports include fuel tanks, refueling facilities, emergency generators, boilers, space heaters, paint booths, and deicing facilities.

GHGs are various gaseous compounds, such as carbon dioxide, that absorb infrared radiation, trap heat in the atmosphere, and contribute to the greenhouse effect/global climate change. Aviation is responsible for approximately three percent of all GHG emissions in the United States. The portion of GHG emissions that an airport operator may be able to manage is that produced by the facilities over which the airport manager has control (i.e., owns and operates), such as stationary sources (boilers, generators, etc.) and airport vehicles. Emissions produced by airport-owned or airport-operated facilities are referred to as Scope 1 or direct emissions. Emissions sources that an airport operator cannot manage or control include those from off-site stationary sources (e.g., power plants), aircraft, and tenant activities (referred to as Scope 2 and 3 emissions).

Some air pollutants emitted by mobile and stationary sources are governed by federal regulations. A GHG reporting rule has been established by the EPA for facilities that emit 25,000 metric tons or more of CO2e annually. Refer to Chapter 3, Air Quality, of ACRP Report 43 Guidebook of Practices for Improving Environmental Performance at Small Airports for an extensive discussion of jurisdictional authority and a summary of applicable air quality regulations.