Since coronavirus is spread by breathing in respiratory aerosols from infected people, it stands to reason that avoiding breathing those aerosols is key to not getting COVID-19. One way to do that, according to a new study, is to keep humidity levels in indoor settings at 40 to 60 percent.
Researchers came to this conclusion after analyzing 10 international studies that were done between 2007 and 2020 looking at the rate of survival and infections of coronaviruses and influenza based on humidity levels in the air.
It was discovered that at higher humidity, the droplets grow faster, fall to the ground earlier and have less chance of inhalation by healthy people, meaning that viruses cannot spread as easily in humid conditions.
Although low humidity causes the droplets containing viruses to dry out more quickly, the survivability of the viruses still seems to remain high. Research concluded that other processes are more important for infection. If the relative humidity of indoor air is below 40 percent, the particles emitted by infected people absorb less water, remain lighter, fly further through the room and are more likely to be inhaled by healthy people. In addition, dry air also makes the mucous membranes in our noses dry and more permeable to viruses.
From the researchers’ point of view, more attention should be paid to indoor air to prevent future outbreaks of viral disease.
HRV/ERV exhausts stale indoor air to the outside, and brings in fresh air from outside. This fresh air is then distributed throughout the home either by the HRV/ERV or by your furnace fan.
In the winter, the warm indoor air passes through the HRV/ERV core as its being exhausted and warms up the incoming fresh outside air. The the summer, the cycle is reversed and the cool indoor air cools down the hot outdoor air recovering the energy. The 2 airstreams never mix when passing through the HRV/ERV core.
https://www.ashrae.org/technical-resources/energy-recovery
During cold and inclement weather, high efficiency filter ventilation systems that recirculate some of the air are an excellent solution.
