Fine and coarse particles were collected for eight weeks during the summer of 1991, at a coastal site (Yaquina Head) and a non-industrial site (Corvallis) in Western Oregon to characterize the aerosol composition and evaluate whether the sites are appropriate for sampling "background" marine air. Concentrations of up to 11 species (S0₄²⁻, NO₃⁻, Cl⁻, Na, Fe, Ni, Pb, Cr, Co, Sb, and CH₃SO₃H) for 95 samples were determined using four chemical analysis techniques. The influences of seasalt and soil dust were identified by analyzing concentrations of Na and Fe in the aerosol samples. Relative elemental composition in fine and coarse fractions indicated that the aerosol composition at Yaquina Head was greatly affected by seasalt. "Seasalt" enrichment factors (relative to Na) indicated that seasalt is the only source of Cl⁻ and SO₄²⁻ in coarse particles at Yaquina Head. In contrast, the seasalt influence was relatively weak at the Corvallis site. "Crustal" enrichment factors suggested that soil dust was not a major source of Na⁺, Cl⁻, or S0₄²⁻ at either site. A simple conceptual model that relies on meteorological conditions was used to identify sampling periods with long range transport from either marine or continental areas as well as local influences. This model suggested that during 61% of the experiment period the aerosols were advected from marine areas. At Yaquina Head, 52% of the sampling periods are associated with the "clean" background air (marine air with no local influences). Thus, Yaquina Head represents a useful location for collecting marine background air from the Pacific Ocean. The chemical composition of the marine background air collected at the Yaquina Head site is similar to that for other remote sites around the world. At Corvallis, "clean" marine background air can occasionally (21%) be collected even though Corvallis is located 64 km from the ocean. / Graduation date: 1993

The purpose of this study is to explore the use of integrated probe vehicle, traffic and land use data to identify and characterize fine particulate matter (PM[subscript 2.5]) hot spot locations on urban arterial corridors. In addition, a preliminary analysis is conducted to consider volatile organic compound (VOC) hot spot locations. A pollutant hot spot is defined as a location on a corridor in which the mean pollutant concentrations are consistently above the 85th percentile of pollutant concentrations when compared to all locations along the corridor. In order to collect data for this study, an electric vehicle was equipped with instruments designed to measure PM[subscript 2.5] and total VOC (TVOC) concentrations. Second-by-second measurements were performed for each pollutant from both the right and left sides of the vehicle. Detailed meteorological, traffic and land use data is also available for this research. The results of a statistical analysis, including multiple regression, are used to better understand which data sources are most valuable in estimating PM[subscript 2.5] hot spot locations consistent with empirical data; knowledge is gained as to which variables have the strongest statistical relationships with traffic emissions and pollutant levels at a corridor level. A preliminary analysis is also completed to consider which variables are statistically related to TVOC hot spot locations. This research highlights the importance of considering both consistency and magnitude of pollutant concentrations when identifying hot spot locations. An objective of this research is to develop a method to identify urban arterial hot spot locations that provides a balance of efficiency (in terms of capital expenses, time, resources, expertise requirements, etc.) and accuracy.