Environmental indicators were developed and evaluated to assess the impact of mobile sources on emissions, air quality, exposure and health. Different levels of indicators are discussed, from single species to multipollutant indicators. Carbon monoxide (CO), Nitrogen oxides (NOx) and elemental carbon (EC) were chosen as indicators of mobile sources because emissions of these pollutants are largely attributed to mobile sources and ambient concentrations have a close response to the change in mobile source emissions. These pollutants were used in the construction of the integrated mobile source indicators (IMSI). The IMSI have larger spatial representativeness and stronger associations with cardiovascular diseases (CVD) than single pollutants. The use of IMSI in epidemiologic modeling constitutes an alternative approach to assess the health impact of pollutant mixtures and can provide support for the setting of multipollutant air quality standards. The human health benefits of reducing mobile sources emissions were more consistent using multipollutant indicators. Indicator values and uncertainties, in the form of indicator sets, are presented with their associated outcomes and attributes to be useful for policy makers who are interested not only in the value of the indicators, but also in their associated uncertainties and their applicability at other times and other regions.

Characterization and Source Apportionment of Ambient PM2.5 in Atlanta, Georgia: On-Road Emission, Biomass Burning and SOA Impact Bo Yan 260 Pages Directed by Drs. Armistead G. Russell and Mei Zheng Various airborne PM2.5 samples were collected in the metropolitan Atlanta and surrounding areas, which are directly impacted or dominated by on-road mobile and other typical urban emissions, regional transport sources, prescribed burning plumes, wildfire plumes, as well as secondary sources with anthropogenic and biogenic nature in origin. Detailed PM2.5 chemical speciation was conducted including over one hundred of GC/MS-quantified organic compounds, organic carbon (OC), water-soluble organic carbon (WSOC), elemental carbon (EC), ionic species, and tens of trace metals. Day-night, seasonal and spatial variations of PM2.5 characterization were also studied. Contributions of PM2.5 major sources were identified quantitatively through the receptor source apportionment models. These modeling results, especially on-road mobile source contributions and secondary organic carbon (SOC) were assessed by multiple approaches. Furthermore, new season- and location-specific source profiles were developed in this research to reflect real-world and representative local emission characterizations of on-road mobile sources, aged prescribed burning plumes, and wildfire plumes. Secondary organic aerosol (SOA), a major component of PM2.5 in the summer, was also explored for sources and contributions.