Humidity May Reduce Coronavirus Transmission

Humidifiers are known to help keep your home comfortable because they maintain healthy humidity levels. Now, as the number of coronavirus (COVID-19) cases increases, many health organizations are encouraging the use of humidifiers to help relieve coronavirus symptoms as well as help prevent the virus’ spread.

Airborne viruses of all kinds, like flu and cold viruses, survive best in homes and buildings with low relative humidity (RH) levels, typically less than 40%. This is because dry air allows the virus to travel more easily and survive on surfaces for a longer period of time. Numerous studies1-6 have shown that raising indoor humidity levels to between 40-60% can help fight airborne infections, like the flu.

“Air humidification acts in a proactive way to combat the spread of viruses by infected people, including so-called super spreaders, even before any symptoms appear or a diagnosis can be made,” explains Dr. Walter Hugentobler in a recent article for Condair.

A 2010 study7 by the American Society for Microbiology set out to examine the effects of air temperature and humidity on two coronaviruses. Their results showed that the greatest level of virus inactivation took place at 50%RH, indicating that maintaining a mid-range RH of 40-60% could be an effective way to reduce the risk of coronavirus transmission.

Healthy humidity levels of 40-60% can also help improve respiratory health, which boosts the immune system’s resistance to airborne viruses. In a 2019 study, the Proceedings of the National Academy of Sciences found that low humidity hinders the immune system’s defenses in three ways:

• Low humidity stops the effective operation of cilia, which are tiny hair-like structures in human airways, that work to remove pollutants.

  
  

• Low humidity inhibits the ability of cells in the lungs damaged by the flu virus to repair themselves.

  
  

• Low humidity caused a failure of infected cells to alert neighboring cells to the virus, and thus fight its spread.

  
  

Adding a humidifier to your home and office are excellent ways to quickly raise indoor humidity levels while also aiding general respiratory health. You should also follow other important measures, like washing your hands frequently, keeping your hands away from your face, cleaning frequently touched surfaces, and staying home if you are sick.

Have questions about adding a humidifier to your home? Give us a call at 800-547-3888 and we can help you select the best unit for your home.

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1. Noti et al, 2013, High humidity leads to loss of infectious influenza virus from simulated coughs, PLoS One. 2013; 8 (2):e57485

2. Yang et al, 2012, Relationship between Humidity and Influenza A Viability in Droplets and Implications for Influenza’s Seasonality, PLoS ONE 7(10): e46789

3. Lowen et al, 2007, Influenza virus transmission is dependent on relative humidity and temperature, PLoS One Pathogens Okt. 2007/Vol. 3/Issue 10/e151

4. Sale, 1972, Humidification to reduce respiratory illnesses in nursery school children, Southern Medical Journal, July 1972, Vol. 65, No 7

5. Gelperin, 1973, Humidification and Upper Respiratory Infection Incidence, Heating, Piping and Air Conditioning, Vol. 45, No.3

6. Green, 1981, Winter humidities and related absenteeism in Canadian hospitals, Digest of the 3rd CMBFS Canadian Clinical Engineering Conference

7. Casanova et al, 2010, Effects of Air Temperature and Relative Humidity on Coronavirus Survival on Surfaces, Applied and Environmental Microbiology, 76 (9) 2712-2717; DOI: 10.1128/AEM.02291-09

8. Kudo et al, 2019, Low ambient humidity impairs barrier function and innate resistance against influenza infection, Proceedings of the National Academy of Sciences, 116 (22) 10905-10910; DOI: 10.1073/pnas.1902840116