Dry air makes sick

the importance of humidity

Date:June 30, 2017in: Safety & Quality7140 Views

Did you know that the right humidity promotes your health and well-being? Whether you're at work, at home, shopping, in a hospital or any other room, the right humidity prevents the spread of infections, flu viruses and other diseases.

In any enclosed space in which many people stay for long periods of time, there is an increased risk of infection with a cold or with the flu virus. When a sick person breathes, speaks, coughs or sneezes, millions of tiny virus-infected droplets spread through the air. Research shows that the chance of survival of these viruses strongly increases when the air indoors starts to become drier.

Viruses survive longer in dry air

In the ambient air, these droplets come together to form an aerosol: a mixture of solid and liquid particles, gases and water vapour that spreads through the air. Depending on their weight and size, these droplets can remain in the ambient air for hours and spread through the building via the ventilation system.

Deactivation at optimal air humidity

Aerosols exhaled by sick people are loaded with viruses and bacteria packed in an aqueous "jacket" of mucus from the respiratory tract, saliva and dissolved salts. As soon as these aerosol droplets leave the body with almost 100% moisture saturation, they enter the much drier ambient air. Here, the droplets shrink almost immediately to approx. half of their original diameter. After the weight loss of almost 90% due to the loss of water, the salt concentration has increased enormously. When the relative humidity in the room falls within the optimal range - 40 to 60% - the salt content rises to a level where most viruses cannot survive and are eliminated. The risk of contamination within this optimal area for the humidity is then minimal.

Preserves dry air

However, things look completely different when the relative humidity in the room drops to less than 40%. This level of humidity causes the dissolved salts to crystallize spontaneously as the aerosols are forced to release even more water into the dry ambient air. Once the salts have crystallised, they are no longer harmful to the viruses. In fact, the opposite happens: the viruses are "conserved", remain active and contagious for longer. The aqueous "wet" aerosol now turns into a "dry" aerosol that contains more active viruses than a "wet" aerosol at a higher relative humidity. The risk of infection with a cold or the flu virus is then much higher than in dry ambient air.

The time bomb "dry aerosols

When these "dry" aerosols are inhaled, the abundant moisture in the airways causes the crystallised salts to dissolve again by absorbing water. The viruses, which are still active, are released to the mucous membranes in the respiratory tract where they can penetrate the cell walls and cause infections.

This is a Google translation from a Dutch site:

https://fmtgezondheidszorg.nl/droge-lucht-maakt-ziek-het-belang-van-luchtvochtigheid/