Richard Hobday writes:

When the influenza pandemic reached the East coast of the United States in 1918, the city of Boston was particularly badly hit. So the State Guard set up an emergency hospital. They took in the worst cases among sailors on ships in Boston harbour. The hospital’s medical officer had noticed the most seriously ill sailors had been in badly-ventilated spaces. So he gave them as much fresh air as possible by putting them in tents. And in good weather they were taken out of their tents and put in the sun. At this time, it was common practice to put sick soldiers outdoors. Open-air therapy, as it was known, was widely used on casualties from the Western Front. And it became the treatment of choice for another common and often deadly respiratory infection of the time; tuberculosis. Patients were put outside in their beds to breathe fresh outdoor air. Or they were nursed in cross-ventilated wards with the windows open day and night. The open-air regimen remained popular until antibiotics replaced it in the 1950s.
Doctors who had first-hand experience of open-air therapy at the hospital in Boston were convinced the regimen was effective. It was adopted elsewhere. If one report is correct, it reduced deaths among hospital patients from 40 per cent to about 13 per cent. According to the Surgeon General of the Massachusetts State Guard:

The efficacy of open air treatment has been absolutely proven, and one has only to try it to discover its value.

Patients treated outdoors were less likely to be exposed to the infectious germs that are often present in conventional hospital wards. They were breathing clean air in what must have been a largely sterile environment. We know this because, in the 1960s, Ministry of Defence scientists proved that fresh air is a natural disinfectant. Something in it, which they called the Open Air Factor, is far more harmful to airborne bacteria — and the influenza virus — than indoor air. They couldn’t identify exactly what the Open Air Factor is. But they found it was effective both at night and during the daytime. [Continue reading…]