Development, Operation and Applications of an Aerosol Generation, Calibration and Research Facility Special Issue ofAerosol Science and Technologyon Findings from the Fine Particulate Matter Supersites Program
An aerosol generation, calibration, and research facility has been developed with the major purpose of evaluating aerosol instrumentation, including quality assurance testing, intercomparison, performance evaluation, and calibration of aerosol sizing, bulk, and speciated mass-measuring instruments. The aerosol facility also provides excellent opportunities for basic aerosol research. Polydisperse test aerosols are generated most often through spray atomization of solutions. Monodisperse test aerosols can be produced by mobility classification of polydisperse aerosols, by a vibrating orifice aerosol generator, by an electrospray aerosol generator, or by nebulization of polystyrene latex (PSL) particle suspensions. Generated inorganic, organic, and mixed aerosol particles range in size from 0.005 to greater than 1 micrometer. Physical characterization of the test aerosols is done using scanning mobility particle sizers, condensation particle counters, and an aerodynamic particle sizer. The facility includes a 450 l cylindrical glass slow-flow chamber that is used mainly for the dilution, equilibration, and controlled humidification of generated primary aerosol particles larger than 50 nm as well as for the generation of secondary aerosols through the choice of appropriate precursor reactants. Test aerosols can also be subjected to controlled concentrations of pollutant gases (O3, NOx, SO2, and VOCs). Smaller particles can also be generated and sampled either from a fast-flow chamber or a static chamber. The well-characterized aerosol environment produced in the slow-flow chamber is used to evaluate the performance of various instruments designed to measure aerosol mass, composition, and size over a range of ambient conditions. Instruments evaluated to date include an R&P standard TEOM mass monitor; a SES TEOM mass monitor; a Differential TEOM mass monitor with an electrostatic precipitator (ESP); R&P Ambient Particulate Sulfate, Nitrate, and Carbon monitors; a Particle-Into-Liquid Sampler with IC (PILS-IC); an Aerodyne Aerosol Mass Spectrometer (AMS); TSI scanning mobility particle sizers (SMPSs); and condensation particle counters (CPCs). Several examples of applications of the aerosol facility involving the TEOM mass monitors and the AMS are also discussed in this article.