Temperature Programmed Thermal Desorption Aerosol Mass Spectrometry (TPTDAMS) for Determining Organic Aerosol Composition

Aerosol particles have important impacts on visibility, acid deposition, climate, and human health; yet, large uncertainties remain in quantifying their chemical composition and atmospheric transformations. A large part of the anthropogenic aerosol is generated from energy-related activities, and organic compounds are known to constitute a significant fraction of ambient aerosol mass in many locations. Of this organic aerosol mass, only a small fraction has been compositionally resolved, and much of the organic aerosol mass remains uncharacterized. Recently, an innovative aerosol mass spectrometer has been developed that can provide size-resolved, quantitative chemical composition data on aerosol particles. In this project, this aerosol mass spectrometer technology will be combined with a temperature-programmed thermal-desorption process that separates organic compounds based on volatility. The combined technology will provide a powerful new tool for in situ time-resolved measurements of the chemical composition of organic-containing particulate matter. Phase I will: (1) design and construct a temperature-programmed thermal-desorption module and integrate it into the aerosol mass spectrometer; (2) conduct laboratory testing and evaluation of the combined technology; (3) evaluate the combined technology with several different ionization methods, including vacuum ultraviolet photoionization and Lithium ion attachment; and (4) design a prototype instrument to be constructed in Phase II. Commercial Applications and Other Benefits as described by the Applicant: The proposed instrument should provide a powerful new tool to the scientific and industrial research communities for detailed measurements of the chemical composition of aerosol particles. The instrument could be employed in ambient pollution monitoring, in chemical and biological warfare agent identification, and in the characterization and control of aerosol emissions from a variety of industrial and energy production processes ¿ processes that produce aerosol-laden gaseous exhaust or waste streams, such as semiconductor manufacturing, gas turbines, and diesel combustors and conventional furnaces used for electrical power.