A method for testing the gas-phase air cleaners using sensory assessments of air quality

Abstract

Present standards prescribe chemical analyses for testing the performance of gas-phase air cleaners. As a part of IEA Annex 78, this study examined a prototype method for testing gas-phase air cleaners based on sensory evaluations of air quality. Four common gas-phase air cleaners were tested using the proposed method. The testing consisted of two phases: Phase 1 ensured that air cleaners had no negative effect on air quality, and Phase 2 provided a detailed characterisation of the removal efficiency of air cleaners. Air cleaners were tested in experimental rooms called field laboratories, and pollution sources comprised of building materials and humans. Thirty-one panellists were recruited. They rated the acceptability of air quality and odour intensity immediately upon entering the rooms and of the air extracted from them and presented in diffusers. Chemical measurements were made as well only in Phase 2. The operation of air cleaners reduced concentrations of VOCs regardless of the pollution source; the perceived air quality was only improved when the pollution source was building materials, supporting the necessity of inclusion of sensory ratings. The results also confirmed that comprehensive testing of air cleaners in Phase 2 should only be performed once it is documented that air cleaners positively reduce pollution exposures in Phase 1. The study followed methodologies proposed by the ISO 16000-44 standard, so the results validate and support this standard. The tests of different air cleaner configurations and the round-robin test are recommended to advance the methodology proposed and examined in the present study.