AAAR 36th Annual Conference October 16 - October 20, 2017 Raleigh Convention Center Raleigh, North Carolina, USA
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PM0.1 Trace Metal Concentrations and Source Apportionment at Four California Sites Using Positive Matrix Factorization (PMF)
WEI XUE, Jian Xue, Peter Green, Michael Kleeman, University of California, Davis
Abstract Number: 601 Working Group: Source Apportionment
Abstract Airborne particulate matter (PM) has been linked to adverse health effects including cardiovascular diseases, respiratory diseases and premature death. Ultrafine particles (UFPs) are suspected to be especially toxic to human health due to their high number concentration, high surface area, and/or their ability to cross cell membranes where they can deliver a dose of potentially toxic material. Epidemiological studies have shown that UFP mass (PM0.1) is associated with premature death in California. Additional measurements of PM0.1 concentrations including the trace metals that could potentially induce oxidative stress would help to understand the mechanisms of injury associated with UFPs.
This study reports results of PM0.1 trace metal measurements at four California cities (East Oakland, San Pablo, Fresno, and Los Angeles) over 12 months of sampling in 2014/15. Two collocated Micro Orifice Uniform Deposit Impactors (MOUDIs) were operated at each site; one was loaded with Aluminum foil substrates for elemental carbon (EC) and organic carbon (OC) analysis, and the other one was loaded with Teflon substrates for trace metal analysis. The substrates for PM0.1 collection were changed on a 3-day basis. The PM0.1 on Teflon substrates were extracted with 25% 1N HNO3 and 75% Acetone, followed by sonication and N2 evaporation. Inductively Coupled Plasma Mass Spectrometry (ICP-MS) was used to quantify 21 elements in collected samples, among which K and Rb could act as tracers for wood burning, and Fe, Zn and Pb could represent source of road dust and on-road break wear. Temporal trend of these elements will be shown and compared among the four representative California cities. This information, combined with EC/OC data, will be used for PMF analysis to identify sources of PM0.1. This PM0.1 concentration, composition, and source apportionment information will act as crucial reference for future epidemiology studies and possibly for future air quality regulation in California.