Characterization of Highway Traffic Plumes in New York City with a High-Resolution Time-of-Flight Aerosol Mass Spectrometer
Abstract
A highly-instrumented Atmospheric Science Research Center-Mobile Laboratory (ASRC-ML) was deployed in summer 2009 to characterize traffic plumes from the Long Island Expressway (LIE), a high-traffic highway in the New York City metropolitan area. In total, four measurement experiments, two in the morning and two in the evening were conducted at ~30m south of LIE. The mass concentrations and size distributions of submicron aerosol species were measured in situ at a time resolution of 1 min by an Aerodyne High-resolution Time-of-Flight Aerosol Mass Spectrometer, along with rapid measurements (down to 1 Hz) of gas-phase species (e.g., HCHO, NO2, NO, O3, and CO2, etc.), black carbon (BC), and number concentrations and size distributions. Meteorology (e.g., wind direction) plays a significant role in controlling the concentrations and chemical composition of aerosols particles. Organics dominate the submicron aerosol composition (> 60%) and vary very dramatically depending on wind directions, with concentration from the northerly wind sectors more than 100% higher than that from the southerly wind sectors, while the variations of inorganic species (e.g., sulfate, ammonium, and nitrate) are rather small. The size distribution of organics shows two distinct modes, peaking at ~120 nm and 500 nm (Dva) respectively in comparison to the single large accumulation mode for inorganic species. Significant enhancements were frequently observed for the ultrafine particle mode of organics and particle number concentrations at ~ 10 nm (Dm) due to the influences of traffic plumes. Positive matrix factorization (PMF) analysis of the organic aerosol (OA) spectra shows that OA in traffic plumes is mainly composed of hydrocarbon-like OA (HOA) and semi-volatile OA (SV-OOA). Our findings may have significant implications for health exposure studies on traffic emissions.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFM.A33E0211S
- Keywords:
-
- 0305 ATMOSPHERIC COMPOSITION AND STRUCTURE / Aerosols and particles;
- 0345 ATMOSPHERIC COMPOSITION AND STRUCTURE / Pollution: urban and regional