Elevated volatile organic compounds and odorant emissions from used air filters due to ozone exposure

Abstract

Due to current lifestyle trends and heightened sensitivity to health, particularly in the post-COVID-19 era, the importance of indoor air quality (IAQ) and odor emissions has increased. Volatile organic compounds (VOCs), which are emitted from various indoor materials are significant air pollutants that adversely affect IAQ and occupant health. In this study, the interactions between ozone (O₃) and residential air filters are investigated to analyze VOC emissions and associated odor intensity (OI) via gas chromatography-olfactometry-mass spectrometry (GC-O-MS). In this study, G4, F7, and F9 air filters exposed to an average O₃ concentration of 100 ppb inside Tedlar bags for 8 hours resulted in significant increases in the VOCs. After O₃ exposure, the G4, F7, and F9 filters resulted in 2.7, 1.1, and 1.4 time increase in VOCs, respectively. Olfactometric analysis revealed a substantial increase in OI after O₃ exposure. The sum of the odor intensities (SOIs) increased from 3.84 to 4.57 in G4, from 3.93 to 4.37 in F7, and from 3.89 to 4.2 in F9. Aldehydes were major contributors to odor, and the key odorants were nonanal, toluene, and paraldehyde. These findings indicated that O₃ not only enhanced VOCs concentration but also intensified the odor issues; thus, targeted improvements are needed to increase IAQ and reduce health risks through improved ventilation systems.