Aerosol Pollution from Theatrical Fog and Haze Machines: Multi-Sensor PM2.5 Exposure Measurements for Public and Occupational Health

This report investigates fine particulate matter (PM2.5) generated by commercial theatrical fog and haze machines, highlighting the severe respiratory and systemic health risks associated with acute and chronic exposure. Following uncontrolled field observations documenting extreme particulate pollution inside active entertainment venues (available at: https://zenodo.org/records/18672551), this controlled pilot study tested the hypothesis that these devices inherently generate hazardous PM2.5 concentrations that exceed established public health thresholds. Using a sealed test enclosure, raw PM2.5 emissions were quantified across four atmospheric machines of varying capacities, ranging from a 40 W miniature handheld fogger to a 1000 W professional unit. Measurements were collected simultaneously using three independent brands of low-cost optical air quality sensors. This research independently corroborates and expands upon the pivotal 2022 reference-grade evaluation by Guo et al. (Impact of glycol-based solvents on indoor air quality—Artificial fog and exposure pathways of formaldehyde and various carbonyls; https://www.researchgate.net/publication/363654700_Impact_of_glycol-based_solvents_on_indoor_air_quality-Artificial_fog_and_exposure_pathways_of_formaldehyde_and_various_carbonyls). Consistent with their findings, the thermal vaporization of glycol and glycerin theatrical fluids acts as a potent generator of hazardous PM2.5. Across all device capacities and fluid types, particulate concentrations repeatedly saturated environmental monitoring hardware, far exceeding the U.S. EPA’s highest “Hazardous” air quality limits. Although theatrical fog machines utilize thermal vaporization mechanisms identical to commercial electronic cigarettes, theatrical devices disperse aerosol volumes orders of magnitude larger, producing localized fine particulate pollution far more severe than secondhand vaping. Because these machines are widely marketed as harmless and non-toxic without any PM2.5 disclosures, explicit health warnings and regulatory oversight are urgently needed to ensure performers, facility staff, and the general public are informed of their exposure. Supplemental Data: The complete supplemental dataset—including raw digital sensor logs, a master compiled spreadsheet, and video recordings of the controlled testing enclosure experiments—is available in a companion repository at: https://zenodo.org/records/21312006.