Condair study shows indoor humidification can reduce the transmission and risk of infection from Coronavirus

The death toll from the Coronavirus 2019-CoV outbreak has now risen to over 1000. Health authorities said there are now more than 42,000 confirmed cases worldwide. The rate of transmission from human to human is influenced by indoor conditions.

Seven dramatic weeks have passed since the Chinese health authorities informed the World Health Organization that there have been mounting cases of pneumonia, the pathogen of which is unknown, in the huge city of Wuhan. Within a short period of time, there has been a rapid increase in the number of officially confirmed cases of illness and death. The pathogen, now identified as Coronavirus 2019-CoV, has been further spread by air passengers, leading to respiratory disease being spread worldwide. On January 30, 2020, World Health Organization declared a public health emergency of international concern.

Coronavirus is closely related to the SARS virus. Laboratories throughout the world have been able to use this information to develop tests to detect the virus. The virus is said to have been transmitted to humans at an open-air meat market in Wuhan, where live wild animals are also sold, and it is now spreading from one human to another. In some of the people who are affected, it causes flu-like symptoms like coughing and difficulty breathing. Lung x-rays confirm severe pneumonia that can lead to death.

“The survival times of SARS coronaviruses on inanimate surfaces and as infectious droplets in the air have been studied. An identical pattern has appeared repeatedly. Very low temperatures (tested at 6°C) and very low humidity (30%) enable viruses to survive for long periods on surfaces and in the air. Even at moderate temperatures of 20-30°C, there was a long survival time, but only when the air was dry. Very high temperatures (>30°C) render the coronaviruses inactive. This is why there have been repeated MERS epidemics on the Arabian Peninsula solely during the cooler winter months. It is assumed that the current Coronavirus will also exhibit a similar behaviour in relation to humidity and temperature. The rate of transmission from human to human is influenced by indoor conditions,” explains Dr. Walter Hugentobler, FMH General Physician, and Dr. Stephanie Taylor, Harvard Medical School, Medical Advisors for Condair Group.

This means that conditions in homes and on public transport where air is typically heated to 20 to 24 degrees for comfort, have resulting low relative humidity from approximately 20 % to 40 %. These are the ideal environmental conditions for SARS coronaviruses to survive on surfaces and in the air over a long period of time, and consequently for increased transmission via contact with contaminated surfaces and inhalation from the air.

“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. Additionally, the respiratory tract’s defences are improved in all people due to the more efficient cleaning of the airways and enhanced immune defences. Raising air humidity by humidification reduces the risk of virus spread in hospitals and other buildings at low-cost and without causing negative effects,” said Hugentobler.

Approximately 58% of SARS cases were acquired from hospital exposure, so humidification of healthcare facilities would be an especially effective intervention to reduce pneumonia and death rates from this new coronavirus strain.

Air humidification can be readily implemented in both private and public buildings, giving people a simple way to actively combat this fearsome virus for which there are currently no vaccines or effective preventive drug treatments. In addition to reducing the overall spread of the outbreak, this intervention also enables each of us to pro-actively take steps to protect the health of ourselves and our loved ones.


“It is not possible for humans to control the outdoor climatic conditions which have allowed this coronavirus to cross species boundaries. However, we are able to manage the indoor environment to support our health and reduce viral disease by regulating critical indoor air factors such as temperature, humidity, air exchange rate and fresh air content. When we maintain indoor temperatures at 20 to 24°C for comfort, it is essential that we decrease our risk of infection by maintaining healthy levels of air humidity and ventilation,” said Hugentobler and Taylor.

Coronavirus Survival on Surfaces

Yale Influenza Study

About Condair Group 
Condair is the leading manufacturer and provider of complete solutions in the areas of humidification and evaporative cooling. This enables us to create the ideal indoor climate while keeping energy consumption low and reducing impact on the environment. With approximately 740 employees, Condair operates production sites in Europe, North America and China and are represented in 22 countries and supported by distribution partners in more than 50 locations worldwide. To learn more visit


The rate of transmission from human to human is influenced by indoor conditions.