A lack of regulation on humidity levels contributes to the spread of viruses.
Public building occupants are being exposed to increased virus risk because the regulations on indoor air quality are falling short on scientific knowledge, says a new press release from Condair. Maintaining air quality at above 40 percent relative humidity has been scientifically shown to reduce viral cross infection. Out of date regulation in buildings such as hospitals and schools, however, sees these buildings experience dangerously low humidity levels each winter.
‘Effects on air temperature and relative humidity on coronavirus survival on surfaces’, a 2010 study by Lisa M Casanova et al, found that coronavirus was deactivated fastest when exposed to mid-range humidity (50 percent RH) as opposed to dry (20 percent) or damp (80 percent). A range of studies stretching back decades indicate 40 to 60 percent humidity as an optimum range in terms of minimising spread risk and people’s susceptibility to viruses.
"The building services sector accepts this indoor humidity level as being best practise," says the release, "with many professional organisations endorsing a mid-range humidity for health in their recommendations. However, there are no official regulations that set an acceptable range of indoor humidity for public places. Therefore, building designers, who are driven to reduce energy consumption and costs, do not commonly include humidity control in their plans."
Indoor air is much drier in the cooler months and the seasonality of viruses is further testament to their transmission in dry atmospheres. Buildings that incorporate humidification into their air ventilation can maintain a healthy humidity level in winter.
“The responsibility to manage indoor air quality ultimately falls on building owners and operators to safeguard occupant health,” says the Condair release. “This is particularly true with regards to healthcare facilities, where people are most vulnerable and at risk to airborne infections such as coronavirus and influenza.”