I found an interesting article from Time 1942 about propylene glycol as an anti viral agent.
A powerful preventive against pneumonia, influenza and other respiratory diseases may be promised by a brilliant series of experiments conducted during the last three years at the University of Chicago’s Billings Hospital. Dr. Oswald Hope Robertson last week was making final tests with a new germicidal vapor—propylene glycol—to sterilize air. If the results so far obtained are confirmed, one of the age-old searches of man will finally achieve its goal.
Crazy. E Cigarette 2nd hand vapour just might be good for you.
Another report states the same benefits of PG when 105 children were exposed in 1945.
Inhalational safety in children. In a series of experiments to control airborne infections, over 105 children were subjected to bactericidal concentrations of propylene glycol in the wards of a children’s convalescent home in experiments conducted over 3 years.
Method. Six wards of the Children’s Seashore House in Atlanta containing 105 bedfast children aged 3 to 15 years were divided into 3 control and 3 undergoing vaporization for 3 week periods with 2 to 3 days between, before the control wards become vaporized, and the vaporized wards became controls. This rotation continued for 7 months. The PG was heated to vaporize it, but not above 80 degrees C, and vaporization continuously maintained a concentration of 0.069 mg per liter. (0.07 ppm)
Results. No ill effects were reported. In the first year, 100 infections occurred in control wards without PG, and 5 in wards with PG vaporization, with rates of 0.18 per week and 0.09 per week respectively. Most of the upper respiratory infections in control wards were common colds, suggesting the PG is also virucidal.
Harris TN and Stokes Jnr, J. Summary of 3-year study of the clinical application of the disinfection of air by glycol vapour. Am. J. Med Sci. 1945; 209:152-156.
I’d be interested in finding more of these types of tests.