Performance of sorption-based portable air cleaners in formaldehyde removal: Laboratory tests and field verification

Formaldehyde is one of the primary indoor air contaminants that widely exists in construction materials and household consumable products. Acute exposure to formaldehyde causes irritation and dermal allergies, while chronic exposure can result in DNA and chromosomal damage. However, only a handful studies have evaluated formaldehyde removal capacities of portable air cleaners (PACs) both in the field and in the laboratory. The laboratory performance of PACs has not been statistically compared with their field performance. This study evaluated the initial formaldehyde removal capabilities of several relatively popular commercial sorption-based PACs in Chinese market by measuring their clean air delivery rates (CADRs) in an 8 m3 environmental chamber. The modified 'pull-down' method was applied in this study, and the total operation time of the tested PACs was 1.5 h. The laboratory results showed wide variations in the CADRs (13.8 m3/h to 75.6 m3/h), which was in agreement with the CADRs reported in previous studies. A single-zone field test under natural ventilation was also conducted in a bedroom with an area of 25 m2 and a volume of 67.5 m3 using the best performing PAC. The results were statistically analyzed for any significant difference between the laboratory and field data. The difference between the laboratory and field performance of the tested PAC was insignificant at a confidence level of 95%.