Representative dilution of aerosols by a factor of 10,000

Measurement of ultrafine aerosol size distributions by a combination of diffusion screen separators and condensation particle counters

“…The DMA was used in a closed-loop set-up similar to the calibration experiments. The aerosol flow which was probed by the CPC combination was diluted by an isokinetic double stage dilution system (VKL-10, PALAS, Karlsruhe, (Helsper, Mölter, & Haller, 1990)). The total dilution factor was about 1.4 × 10 3 .…”

Performance of a venturi dilution chamber for sampling 3–20nm particles

“…The type of dilution chamber selected is a modified version of the venturi-type dilution chamber designed by Koch, Lodding, Molter, and Munzinger (1988). The original design has undergone previous calibration by Helsper et al (1990), for particle sizes of 0.1-10 m. Cheng, Storey, Wainman, and Dam (2002) also showed no discernible difference in dilution efficiency for solid particles of the same particle diameter range, however, they did note some differences for chemical species leading to liquid drops rather than solid particles. Such a dilution system is commercially available in the form of the as Palas ᭨ VKL-10 system and Dekati ᭨ ejector diluter.…”

“…These include for example: the cavity-type diluter which captures a fixed volume of aerosol into a cavity before mixing with particle free air; the venturi-type which operates by drawing a known fraction of particle free sheath air to mix with an aerosol sample; and a capillary-type diluter which uses an aerosol capillary to dilute with filtered air from the original air sample. These systems have been tested by Hueglin, Scherrer, and Burtscher (1997) and Helsper, Mölter, and Heller (1990), respectively, and were all found to perform well. However, some of the more typical capillary systems suffer from high diffusion losses for the smallest nanometer sized particles and thus are not suitable for studies in the nano-particle size range.…”

Construction and Evaluation of an Aerosol Generating Apparatus for Combustion Products from Polyurethane Foam

“…For solid particles the particle size distribution is not expected to change, in the range 0.1-2 m, due to the dilution. (20) However, if the aerosol particles are in the liquid state, the liquid may evaporate, and the particles would become smaller.…”