Characterization of ambient, automobile, and diesel aerosols utilizing aerosol time of flight mass spectrometry

Aerosols play an important role in urban air pollution, health effects, visibility degradation, and climate change. There are many sources of aerosols, such as wind blown dust, sea spray, vegetative detritus, biomass burning, vehicle exhaust, coal combustion, and meat cooking. Aerosol time-of-flight mass spectrometer (ATOFMS) is an instrument capable of measuring the size and chemical composition of single particles in real-time. One of the ultimate goals using ATOFMS is source apportionment. The ability to identify different sources in ambient datasets will help aid policy makers in determining how best to allocate their resources to reduce pollution in their region. The goal of this dissertation is to further the progress using ATOFMS towards source apportionment. This objective will be accomplished through (1) characterization and validation of vehicular emissions through controlled and real-world vehicle emissions, (2) characterization of urban aerosols, and (3) comparing ATOFMS data to other instruments.; Light duty vehicle (LDV) emissions were characterized through the use of a chassis dynamometer and were sampled from a residence and dilution chamber. Twenty-eight vehicles were tested under various driving conditions. Real world heavy duty vehicles (HDV) and LDV emissions were monitored in the Caldecott Tunnel and were well represented by the particle types from the LDV and HDV dynamometer studies. These studies further our understanding of one of the top contributors to urban particulate matter.; A variety of particulate sources were detected in the urban aerosol in La Porte, TX. A semivolatile organic carbon particle type and biomass burning particle type were the dominant particle classes during two separate episodes of high particle number concentration. These results show that the ATOFMS is capable of distinguishing a source (biomass burning) from the rest of the particle types.; The raw and scaled ATOFMS results of two collocated ATOFMS instruments were evaluated and were found to correlate well with each other. Lastly, the ATOFMS data was scaled into mass concentrations with hourly temporal resolution and compared with one hour resolution PM2.5 mass instruments and 24-hour filter based measurements. These two experiments demonstrate that the ATOFMS instrument is reliable and reproducible.