The Use of Artificial Fogs and Indoor Air Quality

Xinyang Guo, Ya-Chun Chan, Toluwatise Ehindero, Chester Lau, RAN ZHAO, University of Alberta

     Abstract Number: 168
     Working Group: Indoor Aerosols

Abstract
Artificial fogs, or stage fogs, are often used by the theatrics and entertainment industries to create special visual effects. Fog droplets are generated by heating a ‘fog-juice’, typically comprised of triethylene glycol, propylene glycol, glycerol, and water. The use of fog machines is often in indoor settings, with smaller and portable types of fog machines also available for individual household use. Previous studies have implied adverse health effects associated with the inhalation of artificial fogs, particularly glycols. However, there were no systematic studies that investigated the impact of artificial fogs on indoor air quality. My team has performed two projects to 1) monitor indoor aerosol and air pollutants arising from the use of a fog machine and 2) identify harmful chemical compounds forming inside the fog juice. Experiments were performed in an unoccupied office. A number of aerosol instruments, including an optical particle counter and a scanning electrical mobility spectrometer were used to monitor the particle size. Particle-into-liquid sampler and mass spectrometry were combined to provide time-resolved chemical information. We found that the use of fog machine gave rise to elevated concentrations of aerosol in the experimental office. Aerosol evaporates within 30 min and gives rise to gas-phase species. We also found that fog juice exposed to room air contained various carbonyl species, including formaldehyde. The formation of these harmful carbonyls is likely caused by oxidants present in the indoor air. Given the low concentrations of radicals indoors, autooxidation of glycols is likely the underlying reaction mechanism.