Stationary and mobile studies of black carbon containing particles with the Soot Particle Aerosol Mass Spectrometer (SP-AMS) in Queens, NY
LEAH R WILLIAMS (1) Paola Massoli (1) Edward C. Fortner (1) N. L. Sally Ng (1) John T. Jayne (1) Timothy B. Onasch (1) Manjula R. Canagaratna (1) Achim Trimborn (1) Douglas R. Worsnop (1)
(1) Aerodyne Research, Inc., Billerica, MA
Abstract Number: 520
Preference: Platform Presentation
Last modified: May 13, 2010
Working Group: Carbonaceous Aerosols in the Atmosphere
The Queens College Air Quality study (Queens, NY, July, 2009) was conducted to characterize the emissions from major city roadways and the impact on the air quality of the surrounding neighborhoods. The Aerodyne Research, Inc. (ARI) mobile laboratory was deployed with state-of-the-art instruments to measure particle concentrations, optical properties and chemical composition, as well as gas-phase pollutants. The recently developed Soot Particle Aerosol Mass Spectrometer (SP-AMS) was deployed to measure refractory soot particles and to provide details on the chemical composition of vehicular exhaust.
The SP-AMS uses laser induced vaporization of black carbon containing particles to measure both the black carbon and any organic and inorganic coatings. Vaporized material is detected with electron impact ionization and a high resolution time-of-flight mass spectrometer. Stationary measurements were performed at Queens College, Queens, NY for two weeks. Data from the SP-AMS are compared with data from a co-located HR-ToF-AMS and show excellent correlation with the hydrocarbon-like organic aerosol component representative of primary emissions.
We conducted gradient studies with the ARI mobile laboratory to determine how concentrations and properties of pollutants vary with distance and time of day from the Long Island Expressway, LIE (>200,000 vehicles per day in Queens) for both downwind and upwind locations. We chose the time frame 0430 - 1000 (local time) to characterize the pollution build-up during the morning traffic rush hours and to investigate the effects of changes in the boundary layer height on the pollution levels. The highest pollutant concentrations were measured within 50 meters of the LIE at any given time; enhancements of 20 to 100% were observed compared to background levels. Pollutant concentrations initially increased in the early morning, peaking around 0700. After 0800, we measured lower pollutant levels as the increase of the boundary layer height allowed vertical mixing and dilution.