Open Air Factor – The forgotten airborne disinfectant

Researcher Dr Richard Hobday explores the historical importance of this germicidal agent’s use and discusses why it has been overlooked by modern medicine

Diseases such as colds, influenza, measles, tuberculosis and Covid-19 spread indoors. Transmission is rare outdoors unless people are standing very close to each other. One reason for this is that the dispersal and dilution of infectious aerosols outdoors prevents them spreading from one host to the next. Variations in temperature, humidity and sunlight levels are also known to reduce the viability of airborne pathogens. But what about the air itself: is that killing them too?

At various times in history there has been a belief that outdoor air can act as a natural disinfectant. And scientific experiments from the 1960s confirm that there is indeed something in fresh air that can kill viruses and bacteria effectively, both during the day and at night. It is now known as the Open Air Factor or OAF. In the past, hospitals were built to exploit fresh air’s germicidal effect and patients put outside to benefit from it. Yet the OAF remains largely unknown. This potentially lifesaving, natural resource has suffered an unusual fate: being discovered and adopted during medical emergencies, only to be abandoned later.

One of the most striking examples occurred following the outbreak of the First World War. The fighting in Belgium was largely conducted on agricultural land that had been heavily manured for years. Troops were often caked in mud and their tunics proved to be a fertile medium for micro-organisms of faecal origin. Injuries from shrapnel were common. Also, when fired at close range, the damage from new high-
velocity rifles was devastating. Both shrapnel and bullets could draw mud and shreds of contaminated clothing deep into wounds and cause life-
threatening infections, which included sepsis, tetanus and gas-gangrene.

In the first few weeks of the war Henry Souttar (1875-1964), a British surgeon working at a field hospital in Belgium, discovered by chance that placing soldiers with badly infected wounds outdoors in fresh air greatly improved their recovery. In his classic 1915 book, A Surgeon in Belgium,1 Souttar explained he did not put them outside for their health; they were put there because the smell of their septic and often gangrenous wounds was too foul to tolerate in the hospital’s wards. When outside their wounds were left open, protected by a thin layer of gauze and treated with ‘liquid oxygen’, probably dilute hydrogen peroxide, which is still used in surgery today.

To Souttar’s surprise the results of exposure to fresh air were ‘almost magical’. Within two or three days, wounds lost their smelland began to look clean. Patients rallied quickly. During the time the hospital was based in Antwerp, before a hasty retreat, there were no cases of tetanus, nor was there any need to amputate a limb. It was not long before soldiers in the trenches were begging to be sent ‘…à l’Hôpital Anglais’.

The British Army rapidly adopted this outdoor approach and set up temporary hospitals to receive convoys of wounded soldiers sent from the front. Many of them were put in tents, huts or purpose-built, open-air wards (Fig 2). The laying open of wounds also became common practice at clearing stations at the front, as bandaging increased the risk of infections developing. Another innovation was combining the germicidal and restorative effects of fresh air with those from careful exposure to sunlight.2

Fresh air and Influenza

The notorious 1918-19 influenza pandemic killed 50 to 100 million people globally and it struck people of fighting age particularly badly.3 In September, 1918, army medical officers at a hospital in Boston in America tried conventional treatments on critically ill sailors. Seven or eight died in rapid succession. One officer noticed the most seriously ill patients had been in badly ventilated spaces onboard their ships. It seemed the problem was lack of air. So, the medical team decided to give their patients as much of this as possible by putting them outdoors in tents. In good weather they took them out of them and cared for them outdoors (Fig 1). It was highly effective. Soon after, the Surgeon General of the Massachusetts State Guard, William Brooks, wrote:

From the first day, the results were startling. Almost every patient without exception had a lower temperature at night than in the morning and felt decidedly more comfortable. The charts of these patients are very instructive and clearly demonstrate the great value of plenty of air and sunshine for patients suffering from influenza and pneumonia.’ 4 (Fig 3)

A few medicines were used to relieve the patients’ symptoms. But these were less important than keeping the patients warm in their beds, giving them nourishing meals and ‘a maximum of sunshine and of fresh air day and night’. Open-air treatment was adopted elsewhere during the pandemic; one estimate was that it reduced deaths among hospital patients from 40 per cent in overcrowded hospitals to about 13 per cent.3

Read the complete article in issue 105.

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