An experimental study of simultaneous coagulation and diffusional deposition of free molecule ammonium sulfate aerosols in turbulent pipe flow is reported. Experiments were conducted at atmospheric pressure, with mean particle sizes ranging from 0.005 to 0.04 μm. Information about particle sizesand concentrations was obtained with a condensation nucleus counter (CNC)-diffusion battery combination; the particle size dependence of CNC counting efficiency was accounted for when reducing the diffusion battery data. Aerosol sizes and concentrations were varied over a wide range so that data ranged from the coagulation-dominated to the diffusional loss-dominated regimes. Data were in good agreement with the theory of Brockmann, McMurry, and Liu [Aerosol Sci. Technol., in press] when coagulation enhancement due to London-van der Waals forces was accounted for.
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This research was supported in part by EPA Grant R807471.