title: Emissions from an international airport increase particle number concentrations 4-fold at 10 km downwind.
abstract: We measured the spatial pattern of particle number (PN) concentrations downwind from the Los Angeles International Airport (LAX) with an instrumented vehicle that enabled us to cover larger areas than allowed by traditional stationary measurements. LAX emissions adversely impacted air quality much farther than reported in previous airport studies. We measured at least a 2-fold increase in PN concentrations over unimpacted baseline PN concentrations during most hours of the day in an area of about 60 km(2) that extended to 16 km (10 miles) downwind and a 4- to 5-fold increase to 8-10 km (5-6 miles) downwind. Locations of maximum PN concentrations were aligned to eastern, downwind jet trajectories during prevailing westerly winds and to 8 km downwind concentrations exceeded 75 000 particles/cm(3), more than the average freeway PN concentration in Los Angeles. During infrequent northerly winds, the impact area remained large but shifted to south of the airport. The freeway length that would cause an impact equivalent to that measured in this study (i.e., PN concentration increases weighted by the area impacted) was estimated to be 280-790 km. The total freeway length in Los Angeles is 1500 km. These results suggest that airport emissions are a major source of PN in Los Angeles that are of the same general magnitude as the entire urban freeway network. They also indicate that the air quality impact areas of major airports may have been seriously underestimated.
authors.affiliation: Keck School of Medicine, Department of Preventive Medicine, University of Southern California , Los Angeles, California 90089, United States.
authors.forename: Neelakshi
authors.initials: N
authors.lastname: Hudda
authors.forename: Tim
authors.initials: T
authors.lastname: Gould
authors.forename: Kris
authors.initials: K
authors.lastname: Hartin
authors.forename: Timothy V
authors.initials: TV
authors.lastname: Larson
authors.forename: Scott A
authors.initials: SA
authors.lastname: Fruin
mesh_terms: D000392:Air Movements; D000393:Air Pollutants / Q000032:analysis; D000401:Aircraft; D059028:Airports; D004784:Environmental Monitoring; D015141:Los Angeles; D008685:Meteorological Concepts; D010316:Particle Size; D052638:Particulate Matter / Q000032:analysis*; D013997:Time Factors; D001335:Vehicle Emissions / Q000032:analysis*; D014919:Wind
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D001335:Vehicle Emissions