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Air monitoring was performed in the vicinity of the Los Angeles International Airport (LAX) during the spring of 2003. The purpose of this monitoring was to determine the extent of airport emissions on downwind ambient air in a mixed use neighborhood that includes residences. A mobile air monitoring platform was developed and deployed to measure ultrafine particle numbers (UFP), size distributions, particle length, black carbon (BC), oxides of nitrogen (NO x ), and particle-phase polycyclic aromatic hydrocarbons (PM-PAH). Pollutant levels were low at a coastal site upwind of the airport, with UFP ranging between 580 and 3800countscm−3, oxides of nitrogen (NO x ) from 4 to 22ppb, black carbon from 0.2 to 0.6μgm−3, and PM-PAH ranged from 18 to 36ngm−3. Markedly higher UFP counts, with average counts of approximately 50,000cm−3, were observed at a site 500m downwind of the airport, which was strongly influenced by aircraft landings and where the community interfaced with airport facilities. Black carbon, PM-PAH, and NO x levels were elevated to a lesser extent at downwind locations. Transient peaks in UFP corresponding to aircraft landings and takeoffs were evident. A maximum UFP count reached 4.8 million particlescm−3 downwind of a runway used by jet aircraft for takeoffs. Particle size distributions differed substantially between upwind and downwind locations. The particle numbers at the upwind site were dominated by particles of approximately 90nm diameter while downwind sites were dominated by particles peaking at approximately 10–15nm. Additional data obtained from a study of UFP levels conducted subsequently by a co-author indicates that aircraft-generated UFP persist up to 900m from an LAX runway [Biswas, S., Fine, P.M., Geller, M.D., Hering, S.V., Sioutas, C., 2005. Performance evaluation of a recently developed water-based condensation particle counter. Aerosol Science and Technology 39, 419–427]. Considered together, these observations suggest that airport operations are associated with elevated levels of UFP much further downwind in the neighboring community than would have been predicted by prior studies of UFP from roadway-traffic. [Copyright &y& Elsevier]

Abstract: Recent health studies have reported that ultrafine particles (UFP) (<0.1μm in diameter) may be responsible for some of the adverse health effects broadly attributed to particulate matter. In urban areas, UFP are produced by combustion sources, such as vehicle exhaust, and by secondary formation in the atmosphere. While UFP can be monitored, few studies have explored the impact of local primary sources in urban areas (including mobile sources on freeways) on the temporal and spatial distribution of UFP. This paper describes the integration of multiple monitoring technologies on a mobile platform designed to characterize UFP and associated pollutants, and the application of this platform in a study of UFP number concentrations and size distributions in Los Angeles. Monitoring technologies included two condensation particle counters (TSI Model 3007 and TSI 3022A) and scanning mobility particle sizers for UFP. Real-time measurements made of NO x (by chemiluminesence), black carbon (BC) (by light absorption), particulate matter-phase PAH (by UV ionization), and particle length (by diffusional charging) showed high correlations with UFP numbers, ( for NO, 0.76 for BC, 0.69 for PAH, and 0.88 for particle length). Average concentrations of UFP and related pollutants varied strongly by location, road type, and truck traffic volumes, suggesting a relationship between these concentrations and truck traffic density. [Copyright &y& Elsevier]