AAAR 32nd Annual Conference
September 30 - October 4, 2013
Oregon Convention Center
Portland, Oregon, USA
Abstract View
Characterization of Size-segregated Particulate Matter in Houston TX
INKYU HAN, Yuncan Guo, University of Texas School of Public Health
Abstract Number: 381 Working Group: Urban Aerosols
Abstract Exposure to ambient particulate matter (PM) is a known risk factor for human health outcomes. While a number of studies have characterized ambient PM between 2.5 and 10 micro meter, limited information is available for the characterization of size-segregated PM including ultrafine particles (UFPs) except particle number concentrations. To characterize UFP in a highly populated urban area, size-segregated PM has been being measured in Houston TX since November 2012. One active sampling site (ASS) is located at a distance of 1 km on the east side of the I-610 freeway where passenger cars and diesel trucks pass by. The other sampling site is located on the roof of University of Texas School of Public Health (UTSPH) representing urban background without known significant combustion sources. At each site a cascade impactor sampler was simultaneously deployed and continuously collected PM for weekly. Size-segregated PM was collected on PTFE filters in 5 size fractions (coarse PM [larger than PM2.5], PM2.5-1, PM1-0.5, PM0.5-0.25, quasi-UFP [PM0.25]) during the weekly sampling periods. We planned to analyze mass concentrations and polycyclic aromatic hydrocarbons (PAHs) by different particle sizes for source apportionment in Houston TX. Between November 2012 and February 2013, preliminary results showed that weekly average concentrations of fine PM in ASS (11.64 micrograms/m3) were significantly higher than UTSPH (7.48 micrograms/m3). The weekly average concentrations of quasi-UFP in ASS (4.84 micrograms/m3) were also significantly higher than UTSPH (3.71 micrograms/m3). The preliminary results suggest that elevated levels of fine PM and quasi-UFP may be attributed to mobile sources during the sampling periods. The future study includes chemical analysis of individual PAHs for the source apportionment of both fine PM and quasi-UFP.