AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
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Comparison of Aircraft Emissions near Los Angeles International Airport (LAX) to Urban Vehicle Traffic Emissions and Its Impact on Air Quality in Los Angeles
FARIMAH SHIRMOHAMMADI, Christopher Lovett, Mohammad Sowlat, Sina Hasheminassab, Arian Saffari, George Ban-Weiss, Vishal Verma, Martin Shafer, James Schauer, Constantinos Sioutas, University of Southern California
Abstract Number: 36 Working Group: Health Related Aerosols
Abstract Among various combustion sources of particulate matter (PM) in urban areas, accurate assessment of airport-related emissions and how they compare to other predominant PM sources such as traffic emissions is essential in understanding the impact of airports on air quality and human health. Air monitoring measurements of particle number (PN), black carbon and PM2.5 mass concentrations were performed in the vicinity of the LAX (roughly 150m downwind of the LAX’s south runways) as well as on-road measurements of the aforementioned pollutants using a mobile platform on three major freeways near the airport (i.e., I-110, I-105, and I-405). PN concentration was, on average, 4.1±1.2 times greater at the LAX site than on the studied freeways. Particles measured at LAX had an average diameter of about 20nm, while on-road freeway measurements on I-110, I-105, and I-405 indicated an average particle diameter of >40nm, a particle size range that is more typical of vehicle traffic and not aircraft emissions in urban areas. Particle number emission factors for takeoffs and landings were comparable, with average values of 8.69×1015 particles/kg fuel and 8.16×1015 particles/kg fuel, respectively, and indicated a nearly 4-fold statistically significant reduction in PN emission factors for takeoffs during the past decade. Moreover, quasi-ultrafine particles (PM0.25) were collected near the LAX airport as well as an urban traffic site close to the I-110 freeway. Samples were chemically analyzed for carbonaceous species (elemental and organic carbons) and individual organic compounds, metals and elements. Redox activity of the PM samples was measured by means of an in vitro alveolar macrophage assay that quantifies the formation of reactive oxygen species (ROS) in cells. ROS activity levels showed little spatial variability, with no statistically significant difference between the averages observed at LAX and the urban traffic site, suggesting similar levels of inhalation exposure to redox active species of PM0.25.