Ultrafine particle removal and generation by portable air cleaners / Article from Atmospheric Environment

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Some of the members on the list may find this article interesting to look up and take the dive into… Atmospheric EnvironmentVolume 42, Issue 20, June 2008, Pages 5003-5014Ultrafine particle removal and generation by portable air cleaners S. Waringa, A. Siegel, a, and L. CorsiaaDepartment of Civil, Architectural and Environmental Engineering, The University of Texas at Austin, ECJ 5.2, C1752 Austin, TX 78712-1076, USAReferences and further reading may be available for this article. To view references and further reading you must purchase this article.AbstractPortable air cleaners can both remove and generate pollutants indoors. To investigate these phenomena, we conducted a two-phase investigation in a 14.75 m3 stainless steel chamber. In the first phase, particle size-resolved (12.6–514 nm diameter) clean air delivery rates (CADR) and efficiencies were determined, as were ozone emission rates, for two high-efficiency particle arresting (HEPA) filters, one electrostatic precipitator with a fan, and two ion generators without fans. The two HEPA air cleaners had count average CADR (standard deviation) of 188 (30) and 324 (44) m3 h−1; the electrostatic precipitator 284 (62) m3 h−1; and the two ion generators 41 (11) and 35 (13) m3 h−1. The electrostatic precipitator emitted ozone at a rate of 3.8±0.2 mg h−1, and the two ion generators 3.3±0.2 and 4.3±0.2 mg h−1. Ozone initiates reactions with certain unsaturated organic compounds that produce ultrafine and fine particles, carbonyls, other oxidized products, and free radicals. During the second phase, five different ion generators were operated separately in the presence of a plug-in liquid or solid air freshener, representing a strong terpene source. For air exchange rates of between 0.49 and 0.96 h−1, three ion generators acted as steady-state net particle generators in the entire measured range of 4.61–157 nm, and two generated particles in the range of approximately 10 to 39–55 nm. Terpene and aldehyde concentrations were also sampled for one ion generator, and concentrations of terpenes decreased and formaldehyde increased. Given these results, the pollutant removal benefits of ozone-generating air cleaners may be outweighed by the generation of indoor pollution.Med Vennlig Hilsen Ole CarlsonMYCOTEAM ASForskningsveien 3BPostboks 5, Blindern0313 Oslo +47 952 38 931  mobil / dir+47 22 96 56 77 adm./kontor+47 22 46 55 52 faksoec@...