Keith Bein - Conditional sampling for source-oriented toxicological studies using a single particle mass spectrometer

Version 1

      Publication Details (including relevant citation   information):

      Bein, K.J., Zhao, Y., and A.S. Wexler, Conditional sampling for   source-oriented toxicological studies

           using a single particle mass   spectrometer (2009), Environmental Science &   Technology, 43(24),



      Current particulate matter regulations control the mass   concentration of particles in the atmosphere regardless of   composition, but some primary and/or secondary particulate matter   components are no doubt more or less toxic than others.    Testing direct emissions of pollutants from different sources   neglects atmospheric transformations that may increase or   decrease their toxicity.  This work describes a system that   conditionally samples particles from the atmosphere depending on   the sources or source combinations that predominate at the   sampling site at a given time.  A single particle mass   spectrometer (RSMS-II), operating in the 70-150 nm particle   diameter range, continuously provides the chemical composition of   individual particles.  The mass spectra indicate which   sources are currently affecting the site.  Ten ChemVols are   each assigned one source or source combination and the mass   spectrometer controls which one operates depending on the sources   or source combinations observed.  By running this system for   weeks at a time, sufficient sample is collected by the ChemVols   for toxicological studies.  This paper describes the   experimental design, implementation and first results from   operating this system in Fresno California during the summer of   2008 and winter of 2009.


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