Frequently, airport operators are being asked to estimate the magnitude of emissions from airport-related sources, including criteria pollutants and Hazardous Air Pollutants (HAPs), and to quantify the contribution of those emissions to local air quality. Significant advances have been made with respect to estimating emissions from airport-related sources, advances that have been incorporated in the U.S. airport emissions modeling tool—Emissions and Dispersion Modeling System (EDMS). However, research has been limited on the relative contribution of airports to local and regional air quality in comparison to non-airport emission sources.
Similar to other sources, emissions of air pollutants released from airport activities are chemically reactive. During their atmospheric evolution, these air pollutants undergo complex transport and physical-chemical processes leading to formation of secondary air pollutants. Besides proper representation of these processes, correct estimation of all airport emissions and their representation in air quality analyses are an essential component in examining the role that airport emissions play in ambient air quality. A combination of ambient air quality measurements and use of modeling tools appears to provide the best framework to extract the needed information. Air quality models are developed to predict regional, local, and subscale concentration distributions of air pollutants; however, ambient measurements are needed to evaluate the predictive capability of these models. Once established to be credible, these models then can reliably be used to study issues of specific interest.
A combined modeling-measurement approach is often used in air quality analysis; however, its use in airport-related air quality analysis is in its infancy. At present, there are two independent projects planned that will employ this approach for air quality analysis: TF Green International Airport in Providence, Rhode Island, and Los Angeles International Airport. In addition, there are ongoing modeling studies at Chicago O’Hare and Atlanta Hartsfield airports. Findings from these studies will be valuable for the airports under study; however, to broaden the applicability of these results, there is a need to carry out similar studies for other airports. These additional studies will enable the formulation of detailed guidance for modeling and measurement analysis to estimate airport contributions to ambient air quality. Research is needed to develop this guidance, assessing and evaluating the state of the art in modeling technology available to airports throughout the country designed to quantify the impact of airport emissions on ambient air quality.
The objective of this research project is to provide guidance for airport operators on effective tools and techniques for measuring airport contributions to ambient air quality. The research will evaluate existing and potential monitoring strategies and forecasting techniques that airport operators can use to measure airport-related air quality impacts on local jurisdictions that may exceed what is traditionally measured and modeled for National Environmental Policy Act (NEPA) purposes. The evaluation process will require selection of a specific airport as a test case for application of a combination of air quality measurement and state-of-the-art modeling techniques and an evaluation of the results of that application. This research project will identify gaps in existing models and the inputs to those models, future research needed to fill those gaps to improve the predictive capabilities of available models, a set of detailed recommendations for implementing an optimal emissions monitoring and forecasting strategy, and guidance to airport operators on how to select and carry out that strategy.
Status: The final report has been published as ACRP Report 71.