Security code

Case study: Humidity vs influenza virus

"Studies show that maintaining relative humidity at 40% can significantly reduce the impact and transmission of the airborne influenza virus"


Recently an article appeared in the CIBSE journal and many other publications about the crucial impact of using humidification to combat the infectivity of the airborne influenza virus. The study referred to is very detailed and is another confirmation of a growing body of evidence which has been around since the 1970s. The key point here is to understand the very considerable benefits from humidifying the workplace.


The news that humidification significantly reduces flu transmission is receiving well-deserved publicity and is something we here at Gibbons have been utilising and aiding our customers with for several years. We install many humidification systems which live up to this as well as advising clients about these very benefits.  


The article is based on a study carried out last year by the US National Institute for Occupational Safety and Health (NIOSH). The study itself examined the role of relative humidity in the aerosol transmission of influenza, by creating a simulated examination room with coughing and breathing manikins. Aerosols of the virus were coughed into the room’s atmosphere by the manikins, ranging from 7-73% relative humidity (RH). The air intake from the other, breathing manikin was recorded simultaneously with this. 


Image taken from original NIOSH study;


The study found that maintaining indoor relative humidity at >40% will greatly reduce the infectivity of the aerosolised virus. At low RH the influenza virus retained maximal infectivity, whereas at higher levels of RH the inactivation of the virus occurred rapidly after coughing. 


With an estimated 7.6m working days lost in the UK each year due to flu-related illnesses it is no surprise that employers, scientists, workers and humidification suppliers alike are keen to prove and express the importance of humidity levels indoors and in the workplace. The truth is that this knowledge has been around for some time and is a key piece of information that employers and maintenance departments need to consider when valuing the importance of their humidification systems. It’s quite common that these systems are being turned off in order to reduce operating costs, and this is where Gibbons can help, keeping viruses out of the work force and improving productivity.  


                          Chart showing the reduction of virus infectivity at different humidity level fractions. 

Here at Gibbons our humidification systems are all low-energy fully-modulating systems and provide the opportunity to replace steam humidifiers with an energy-efficient alternative. This achieves very large energy savings and greatly reduces maintenance, which is the main concern of business owners who are currently turning off their systems to reduce costs. In many applications the energy savings have paid for the Gibbons humidification system in less than one year! 


If you're interested in finding out more, please contact our Managing Director of Humidification Steve Rix on or visit our Humidification page.


To read the full study carried out by NIOSH, click here.

Follow Me on PinterestGoogle+ Me


Add comment

Back to Blog