Source profiling and apportionment of airborne particles: A new approach using aerosol time-of-flight mass spectrometry.

摘要

Aerosol time-of-flight mass spectrometry is a state of the art analytical method that allows for single particle size and chemical analysis of airborne particulate matter in an on-line fashion. The instrument has shown great potential for analysis of ambient particulate matter and classification of particle types based on unique chemical compositions. In this work, the application of this technique for analysis and identification of different particle sources is investigated. There are three parts to the research presented: (1) characterization of the mass spectrometer region of the instrument, (2) a series of source emissions tests, and (3) analysis of ambient Riverside particle data.; The focus of the first part is characterization of the mass spectrometer. To accomplish this, a series of organic and inorganic standards have been analyzed with the instrument. For the organic compounds, this represents the beginning of a mass spectral library that aids in understanding the characteristic ions that different classes of compounds give in the instrument. For inorganic species, response factors have been determined for a variety of elements, in order to give a rough understanding of the detection efficiency of different species.; The second part of the research is a series of source emissions tests to examine particulate matter on an individual particle level. This represents the first systematic chemical analysis of a number of different particle sources with an individual particle technique. Analysis of the particles indicates that unique chemical tracer species can be identified in almost every case. Sources that have been analyzed include vehicle exhaust emissions, biomass burning, meat cooking smoke, soil dust, road dust, brake dust, and vegetative detritus.; Finally, the last part of this work describes analysis of ambient data acquired with the instrument and focuses on the application of source tracer markers to ambient data. The first single particle source apportionment is attempted with the data provided by the instrument, with promising results. A description of how to convert single particle source data into real atmospheric mass contributions is included.