The healing properties of fresh air have been appreciated since ancient times,first When Pliny the Elder (AD 23-79) advised people with tuberculosis to breathe in the air of evergreen forests, where there was a high concentration of ozone, a known germicide.2
In recent history, outdoor air has been considered part of the standard treatment for tuberculosis and other infectious diseases.3 Ironically, today’s “high-tech” hospitals, with their closed, indoor wards, can facilitate the spread of disease more than the outdoor hospitals of years past.
In the 1960s, scientists studying biodefense coined the term “open air factor,” or OAF, to describe the germicidal component of outdoor air that has the ability to kill pathogens and reduce their infectivity.4 However, interest in using open air to promote health and reduce infectious disease died out in the 1970s, and has remained largely ignored since.
In a review article published in Cureus, infectious disease expert Peter Collignon of the Australian National University is calling for more urgent investigation of the outdoor air factor, particularly as it relates to COVID. -19, said: “[W]immediate action is needed, as there is sufficient evidence to suggest that general public health would improve if more emphasis was placed on increased exposure to outdoor air. “5
History of open air healing
According to Collignon, the therapeutic effects of outdoor air were “widely exploited” in the late 19th and early 20th centuries. “First, in the treatment of tuberculosis patients undergoing ‘open-air therapy’ ‘ at the sanatorium; and the second by military surgeons during the First World War,” he wrote. “They used the same outdoor regimen in hospital wards specifically designed to disinfect and heal wounded soldiers.”6
The English physician John Coakley Lettsom (1744-1815) was one of the first to advocate what was later called the “open-air method”. Researchers, writing in the American Journal of Public Health in 2009, exposed children with tuberculosis to “sea air and sunlight at the Royal Bathing Hospital in Kent, England. “.7
The bactericidal effect of fresh air was further exploited during the influenza pandemic of 1918-1919, when it was common to place sick people outdoors in tents or in outdoor hospitals. Records from an open-air hospital in Boston, Massachusetts, during a Spanish flu outbreak from 1918 to 1919 show that patients and staff there were spared the worst of the outbreak.8
Fresh air and sunlight are two things that are noticeably lacking in modern hospitals, but they are abundant at Camp Brooks Hospital, which has treated hundreds of patients during the annual flu pandemic. 1919. Treatments take place outdoors to make the most of sunlight and fresh air.
The Massachusetts State Guard Surgeon General, William A. Brooks, reported that in a typical general hospital with 76 cases of influenza, 20 patients died in a 3-day period while 17 nurses were sick. Sick. “By contrast,” the researchers wrote, “by one estimate, the regimen applied at the camp reduced the mortality rate of hospital cases from 40% to about 13%.”9
In the event of a future pandemic, they note, improvements in portable air handlers and filters could be warranted for hospitals and other buildings, but better yet, “More could be achieved by introducing high levels of natural ventilation or indeed by encouraging the public to spend as much time outdoors as possible. “ten
Then, in the 1950s, an open-air regimen was proposed as a treatment for mass burns in the event of a nuclear war. Collignon writes: “In conditions of such calamities, the quantity of ice and the means to use them is hardly sufficient. “Outdoor treatments are considered the only viable treatment. Infection control is considered the ‘salient feature’ of this approach. “11
Open Air’s germicidal factor
There are many factors that reduce the risk of infection in outdoor spaces. Infectious particles are diluted and dispersed faster, in the first place, while changes in temperature and humidity can inactivate the virus. Ultraviolet rays from the sun are also known to inactivate viruses like flu and coronavirus,twelfth Not to mention that sunlight increases a patient’s vitamin D levels, a deficiency that can increase susceptibility to flu and other respiratory infections.13
However, the direct bactericidal properties of outdoor air are blatantly ignored, even though a 1968 study published in the journal Nature showed bactericidal properties in rural air.14 Experiments show that outdoor air is more deadly than indoor air, and scientists have developed a technique to measure the effects of outdoor air on bacteria survival. , viruses and spores. Collignon explains:15
“The initial tests were carried out during the dark hours because, in common with other bacteria and viruses, E. coli is quickly killed by sunlight. E. coli samples exposed to outside air often die quickly, but not indoors.
Sometimes, samples of E. coli in free air lose viability for 30 minutes, while samples in closed air survive for several hours. The bactericidal effect varies from night to night, and it disappears quickly in any form of enclosure.”
In addition to E. coli, outside air is also effective against viruses and other bacteria, including Brucella suis, Francisella tularensis, Staphylococcus epidermidis, Group C Streptococcus, and Serratia marcescens.
The germ-killing component of the air is known as OAF, but the researchers weren’t able to determine exactly what it was made of at the time. In the 1970s, other researchers determined that OAF was not a single compound but “a mixture of highly reactive, diverse chemical species”.16
In 2021, experts in atmospheric sciences once again review the OAF, agreeing that no single molecule or class of molecules appears to be responsible for the reported high levels of biocidal activity. .17 They even concluded that hydroxyl radicals (HO), a component of OAF known to destroy airborne pathogens, were not responsible for the observed bactericidal activity. They concluded:18
“We identified other potential candidates, which are formed in the ozone-alkenes reaction and have known (and possible) bactericidal properties, but the compounds that cause OAF remain a mystery. “
The ongoing mystery of how the OAF works may be a key reason why it continues to be neglected in the public health and infection control arenas, Collignon said.19 despite the fact that fresh air is free and cannot be smoked is another probable factor.
Can increased ventilation preserve OAF indoors?
OAF research in the 1960s showed that the bactericidal effect of outdoor air could be maintained in a simulated indoor form if the ventilation rate was sufficiently high.20 Specifically, 30 to 36 air changes per hour are required to protect OAF.
A study of old hospital wards before the 1950s used by TB patients – which had large windows and high ceilings – showed that they had ventilation rates of 40 air changes per hour – and a TB infection rates are lower than in more modern hospitals.21 The reality is that modern hospitals are super-spreaders of disease.
A rapid review and meta-analysis of 40 studies found a high rate of nosocomial (hospital-originated) infections, noting: “As patients potentially infected with SARS-CoV-2 require hospital, the rate of nosocomial infections can be expected to be high.”22
The researchers looked at case reports of nosocomial infections of COVID-19, SARS (severe acute respiratory syndrome) and MERS (Middle East respiratory syndrome), showing that, among the diseases confirmed patients, the nosocomial infection rate was 44% for COVID-19. , 36% for SARS and 56% for MERS. Healthcare workers are thought to have accounted for 33% of COVID-19 cases in hospitals, with nurses and doctors being the most commonly infected healthcare workers.
Meanwhile, the importance of proper ventilation continues to be overlooked, even as a study by the US Centers for Disease Control and Prevention found improving ventilation, such as like opening windows, reduces COVID-19 cases in Georgia schools more than wearing a mask. for staff and teachers.23 According to Collignon:24
“Decades ago, hospitals and other types of buildings were designed to prevent infections from spreading. A high degree of natural ventilation is an absolute requirement.
They are not like that today. Fresh air is no longer considered to kill bacteria or treat hospital patients or anyone else for this matter. Buildings are no longer designed for free access to it. For example, with smaller windows, lower ceilings, cross ventilation can be difficult if not impossible, and balconies and patios are not as common as they once were.”
It’s time to rediscover the power of fresh air
It was 1914 when Dr. Robert Saunby, professor of medicine at the University of Birmingham, declared, “Why are we so slow to realize that fresh air is the best tonic, the best disinfectant?”25 Collignon believes it’s time we pay attention to the importance of fresh air – in hospitals, schools, offices and other buildings – and harness its healing effects in prevention and infectious disease treatment. He is calling for:26
- Test to determine the effect of OAF on new and established pathogens
- Research to determine how long OAF can be stored indoors and how best to store it
- Evaluating building design with a focus on increased exposure to outdoor air and OAF to improve infection control and patient recovery
On an individual level, it’s important to take advantage of the resiliency of fresh air as much as possible by opening windows and spending time outdoors, especially in natural areas. Furthermore, Collignon suggests, “rediscovering” outdoor areas and outdoor regimens may benefit hospital patients, while harnessing OAF may also be helpful to reduce transmission disease in the community, including schools, homes, offices and other large buildings.27
