AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Source Characterization of Aerosol Metal and Trace Element Measurements in High-Time Resolution
CHEOL-HEON JEONG, Jon M Wang, Greg J. Evans, SOCAAR, University of Toronto
Abstract Number: 504 Working Group: Urban Aerosols
Abstract Traffic-related atmospheric pollutants often exhibit high temporal and spatial variability near roadways. Chemical compositional measurements in high-time resolution of particulate matter (PM) become crucial in order to evaluate exposure to these pollutants. Further, the variation in concentrations with time of day or meteorological conditions can help to elucidate and resolve the contributions of local traffic-related sources as compared to city-wide and regional scale sources. While versatile near real-time analytical methods of major inorganic and organic PM chemical species have been developed, the measurement of metals and trace elements in PM is often limited by labour-intensive conventional analysis, i.e., filter sampling methodology. Fast quantitative analysis of PM metals in conjunction with major organic/inorganic PM chemistry measurements can lead to more effective source identification.
Hourly concentrations of 23 metals including Ag, As, Ba, Br, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mn, Ni, Pb, Rb, Se, Si, Sn, Sr, Ti, V, and Zn were measured by the Xact 625 Particulate Metal Monitor (Pall) in downtown Toronto, Canada. The Aerosol Chemical Speciation Monitor (ACSM, Aerodyne) was used for measuring the atmospheric sulphate, ammonium, nitrate, and organic matter in PM at a time resolution of 30 minute. The quantitative and optical properties of carbonaceous compounds were obtained by a field thermal-optical OCEC analyzer (Sunset Lab), a photoacoustic soot spectrometer (PASS, DMT), and a 7-wavelength aethalometer (AE33, Magee Sci).
This presentation will describe the contributions of different local sources and processes identified by applying positive matrix factorization (PMF) analysis to the high-time resolution PM speciation data. Temporal variability in PM sources at the metropolitan site will be further explored and presented.