AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Seasonal Variations and Regional Sources of Ultrafine Particulate Matter at a Semi-Rural Site on the Olympic Peninsula
LAUREN WHYBREW, Cassandra Gaston, Felipe Lopez-Hilfiker, Odelle Hadley, Honglian Gao, Fran McNair, Dan Jaffe, Joel A. Thornton, University of Washington, Seattle, WA
Abstract Number: 622 Working Group: Source Apportionment
Abstract Currently, there are air quality standards for the mass concentration of particles less than 2.5 micrometers in diameter, PM2.5. However, there are no standards for ultrafine particles, i.e. those smaller than 0.1 micrometers, even though studies have shown that ultrafines can cause negative respiratory health effects beyond that of PM2.5 due to their smaller size. The mass and number concentrations of ultrafines, and therefore their sources, are not well characterized. To address this, we use a Scanning Mobility Particle Sizer (SMPS) to measure ultrafine particle concentrations and size distributions in Port Angeles, Washington, a region that has many local sources such as traffic, residential biomass burning, ship emissions, and industrial biofuel operations. The SMPS has been operating continuously since December 2013, providing us with measurements at a five-minute time resolution. In addition to the SMPS, we include a compositional analysis obtained from a high resolution, time-of-flight chemical ionization mass spectrometer (HR-ToF-CIMS) equipped with a FIGAERO inlet capable of measuring chemical compounds in both the gas and particle phases. The goals of this project are to gain insights into the primary sources of ultrafine particles in this region by using the observed diurnal and seasonal variations in ultrafine particle abundance, together with auxiliary data sets that include meteorological parameters and other chemical tracers of various pollutant sources. We observed seasonal differences in the diurnal profile and total number concentrations of ultrafine particles at this site due to differences in meteorological conditions and sources. Higher concentrations observed in winter were likely due to emissions from residential biomass burning as confirmed by observed biomass burning markers obtained by the FIGAERO HR-ToF-CIMS. These insights will then be used to evaluate the effectiveness of local air quality regulations.