There is growing concern in communities surrounding airports regarding the contribution of various emission sources (such as aircraft and ground support equipment) to nearby ambient concentrations. Within this study, we conducted extensive monitoring in neighborhoods surrounding T.F. Green Airport in Warwick, RI, to determine the marginal contribution of the airport to concentrations of various pollutants and to determine the subset of pollutants where airport emissions contributed appreciably to measured concentrations.
Monitoring was conducted in three intensive one-week campaigns, across three seasons in 2007 and 2008. Numerous pollutants were measured at three stationary sites surrounding the airport in different wind directions, including continuous measurements of ultrafine particle counts, black carbon, fine particulate matter (PM2.5), and nitric oxide, along with integrated samples of PM2.5, PAHs, nitro-PAHs, VOCs, and carbonyls. The integrated samples had averaging times ranging from 6-hour to 24-hour, capturing diurnal variability in concentrations when feasible. Passive samplers for nitrogen dioxide were deployed at numerous sites near the fenceline and at varying distances from the airport and major roadways. Mobile continuous monitoring of ultrafine particle counts, particle-bound PAHs, and PM2.5 was conducted to determine spatial patterns of these pollutants across multiple neighborhoods, using GPS instruments to record location as well as significant source events. In addition, real-time wind speed and direction data were collected with multiple sonic anemometers, and noise monitoring was conducted to provide a real-time determination of flight activity. The timing of flight take-offs and landings was also gathered within a database that included aircraft type.
Analyses suggest spatial heterogeneity in nitrogen dioxide across the sampling domain, with higher levels in areas near the terminal building and downwind from major roads. Evaluation of continuous measurements at the stationary sites indicates higher concentrations of particle-bound PAHs, ultrafine particle counts, and black carbon during periods when the sites were downwind from the airport grounds. VOC and carbonyl data demonstrated a high detection rate and significant correlations among BTEX compounds. Formal regression analyses on continuous monitoring data utilizing flight activity as well as meteorological data suggest significant influences of wind speed and direction and provide for quantification of the marginal contribution of airport sources relative to other nearby sources.
We conclude that intensive multi-pollutant monitoring campaigns surrounding airports or other defined sources can be an informative way to determine the marginal contribution of these sources to ambient concentrations, especially for pollutants and geographic domains that are not easily captured with atmospheric dispersion models.