Improved source apportionment and speciation of low-volume particulate matter samples.

New chemical analysis methods for the characterization of atmospheric particulate matter (PM)* samples were developed and demonstrated in order to expand the number of such methods for use in future health studies involving PM. Three sets of methods were, developed, for the analysis (1) of organic tracer compounds in low-volume personal exposure samples (for source apportionment), (2) of trace metals and other trace elements in low-volume personal exposure samples, and (3) of the speciation of the oxidation states of water-soluble iron (Fe), manganese (Mn), and chromium (Cr) in PM samples. The development of the second set of methods built on previous work by the project team, which had in the past used similar methods in atmospheric source apportionment studies.

Temporal trends in motor vehicle and secondary organic tracers using in situ methylation thermal desorption GCMS.

Organic aerosol measurements with high temporal resolution can differentiate primary organic carbon (POC) from secondary organic carbon (SOC) and can be used to distinguish morning rush hour traffic emissions and subsequent photo-oxidation. In the current study, five hour filter samples were collected during the Summer Study for Organic Aerosols at Riverside (SOAR-1 in CA, USA) for analysis of organic molecular markers. To achieve the low detection limits required for the high temporal resolution data, a laboratory-based in situ methylation thermal desorption gas chromatography-mass spectrometry method was developed.

Tracking personal exposure to particulate diesel exhaust in a diesel freight terminal using organic tracer analysis.

Personal exposure to particle-phase molecular markers was measured at a trucking terminal in St Louis, MO, as part of a larger epidemiologic project aimed at assessing carbonaceous fine particulate matter (PM) exposure in this occupational setting. The integration of parallel personal exposure, ambient worksite area and ambient urban background (St Louis Supersite) measurements provided a unique opportunity to track the work-related exposure to carbonaceous fine PM in a freight terminal. The data were used to test the proposed personal exposure model in this occupational setting: To accurately assess the impact of PM emission sources, particularly motor vehicle exhaust, and organic elemental carbon (OCEC) analysis and nonpolar organic molecular marker analysis by thermal desorption-gas chromatography/mass spectrometry (TD-GCMS) were conducted on all of the PM samples.

Characterization of metals emitted from motor vehicles.

A systematic approach was used to quantify the metals present in particulate matter emissions associated with on-road motor vehicles. Consistent sampling and chemical analysis techniques were used to determine the chemical composition of particulate matter less than 10 microm in aerodynamic diameter (PM10*) and particulate matter less than 2.5 microm in aerodynamic diameter (PM2.

Emissions of metals associated with motor vehicle roadways.

Emissions of metals and other particle-phase species from on-road motor vehicles were measured in two tunnels in Milwaukee, WI during the summer of 2000 and winter of 2001. Emission factors were calculated from measurements of fine (PM2.5) and coarse (PM10) particulate matter at tunnel entrances and exits, and effects of fleet composition and season were investigated.