Glycol Vapors in Emergency Airborne Pathogen Transmission Suppression

Air disinfection technologies that can be rapidly and broadly deployed during pathogen outbreaks represent a critical gap in pandemic preparedness. Though existing measures, including ventilation, filtration, and germicidal UV, can reduce airborne disease transmission in shared spaces, their emergency use is constrained by cost, energy, deployment speed, or scalability (Lerner et al., 2025). Propylene (PG), dipropylene (DPG), and triethylene (TEG) glycol vapors present a promising alternative for transmission suppression in occupied spaces.

Our objective was to comprehensively evaluate the potential of glycol vapors as emergency airborne transmission countermeasures to inform preparedness strategies. Glycol vapors have demonstrated rapid inactivation efficacy among diverse pathogens including bacteria, viruses, and fungal spores (Mellody & Bigg, 1946; Robertson et al., 1942; Styles et al., 2023). While variation exists among controlled chamber studies, there is evidence that glycol vapors can optimally achieve ~3-6 log reductions/hour against bioaerosols under optimal environmental conditions (Robertson et al., 1942; Sultan et al., 2024). Historical field trials have reported effective glycol-mediated disease transmission suppression, including a 63-95% decrease in respiratory infections when PG or TEG vapors were deployed in a convalescent ward while non-airborne routes of transmission were controlled (Harris & Stokes, 1945). Limited adverse effects have been reported following PG, DPG, or TEG exposure, with safety assessments indicating negligible to low toxicity for healthy adults within efficacious concentrations (U.S. EPA, 2017). Furthermore, protecting indoor spaces with glycol vapors is inexpensive compared to other technologies (Lerner et al., 2025).

We identified knowledge gaps including deployment feasibility using commonly available dispersion methods, safety among potentially sensitive populations, and interactions with filtration media, which we are actively funding. The convergence of inactivation efficacy, safety profiles, and potential rapid deployment position glycol vapors as a promising pandemic preparedness strategy, while our research initiative addresses remaining questions to enable evidence-based deployment protocols for emergency use.

References
Harris, T. N., & Stokes, J., Jr. (1945). Summary of a 3-Year Study of the Clinical Applications of the Disinfection of Air by Glycol Vapors. The American Journal of the Medical Sciences, 209, 152–156. https://www.jefftk.com/harris-and-stokes-1943.pdf

Lerner, A., Mainelis, G., Hallman, W., Kipen, H., Magalhaes, M., Buckley, B., Cedeño Laurent, J. G., & Eyal, N. (2025). Managing infectious aerosols to counter engineered pandemics: Current recommendations and future research. Risk Analysis: An Official Publication of the Society for Risk Analysis, 45(10), 3045–3078. https://doi.org/10.1111/risa.70054

Mellody, M., & Bigg, E. (1946). The Fungicidal Action of Triethylene Glycol. The Journal of Infectious Diseases, 79(1), 45–56. https://doi.org/10.1093/infdis/79.1.45

Robertson, O. H., Bigg, E., Puck, T. T., Miller, B. F., & Technical Assistance of Elizabeth A. Appell. (1942). The bactericidal action of propylene glycol vapor on microorganisms suspended in air. I. The Journal of Experimental Medicine, 75(6), 593–610. https://doi.org/10.1084/jem.75.6.593

Styles, C. T., Zhou, J., Flight, K. E., Brown, J. C., Lewis, C., Wang, X., Vanden Oever, M., Peacock, T. P., Wang, Z., Millns, R., O’Neill, J. S., Borodavka, A., Grove, J., Barclay, W. S., Tregoning, J. S., & Edgar, R. S. (2023). Propylene glycol inactivates respiratory viruses and prevents airborne transmission. EMBO Molecular Medicine, 15(12), e17932. https://doi.org/10.15252/emmm.202317932

Sultan, Z., Luhung, I., Aung, N. W., Uchida, A., Natarajan, A., Puramadathil, S., Li, J., Schuster, S., & Schiavon, S. (2024). Effectiveness of triethylene glycol disinfection on airborne MS2 bacteriophage under diverse building operational parameters. Indoor Environments, 1(3), 100042. https://doi.org/10.1016/j.indenv.2024.100042

U.S. Environmental Protection Agency. (2017). Propylene Glycol, Dipropylene Glycol and Triethylene Glycol Interim Registration Review Decision Case Numbers: 3126 and 3146.