There is undoubtedly a link between air purity and Covid-19 and now more than ever has the cleanliness of the air we breathe become such a critical factor. For the first time that I can recall, aspects of my field of work such as ventilation and air quality are being discussed by the media on a daily basis.

As many of us working within this industry, who are regularly dealing with condensation and moisture laden air issues will now be aware, it  appears that the conditions required for surface mould growth to occur seem to be very similar to the environment needed for virus particles to remain viable.

As BS5250: 2011 states: “As a guide if the average humidity within a room stays above 70% for several days, the relative humidity at external wall surfaces will be above 80%, which is high enough to support the germination and growth of moulds”.

mould on wall


Parallels can be drawn from a recent study showing that maintaining a mid range humidity level would be an effective measure to reduce the risk of coronavirus transmission.

But even before the COVID-19 pandemic took hold, international experts and governments from around the world have been advocating the importance of refreshing air and maintaining a relative humidity of between 40% – 60%.

Since the recent easing of restrictions that lockdown first brought in, instructions from our government have placed an emphasis on the scientific fact that the virus transmission is lower in outside spaces compared to indoors. However, while it is easy to be outdoors during the summer months, we must be mindful of the challenge that winter will bring when temperatures fall and our climate becomes less suited to outdoor pursuits. It is at this point that we close our windows and switch on the heating, both of which have a detrimental effect on the quality of the air that we breathe.

Wintertime Could Be Covid-19 Time

Following a recent study by the University of Sydney and the Fudan University School of Public Health in Shanghai, Professor Michale Ward has said: “Covid-19 is likely to be a seasonal disease that recurs in periods of lower humidity. We need to be thinking if it’s wintertime, it could be Covid-19 time.”

wintertime covid-19 time

Homeowners, tenants, shops, offices and institutions should all be giving careful consideration now as to how they can ensure regular air exchange which in turn will provide good quality clean air that will keep us fit and healthy.

Fresh Clean Air = Good Health

One of the most effective methods for the homeowner or tenant is to use a Positive Input Ventilation (PIV) system. This consists of a slow speed fan set into the loft which continuously draws clean fresh air into the roof space from the outside via the loft’s natural leakage points such as the eaves. It then gently pushes the filtered air into the property through a ceiling vent which is usually situated in the central hall or stairwell.

PIV system

Loft Installed PIV System

PIV ceiling vent

Ceiling Vent







Wall mounted PIV systems are also available for flats and basements or properties without a loft space. These work in a similar way to the above system although this unit is often situated in the entrance hall or kitchen, and discharges fresh filtered air into the central hallway via a ducting system.

wall mounted PIV system

Wall Mounted PIV System

Improving air quality goes hand in hand in containing the spread of coronavirus and forethought should be given to ensuring that this winter we are maintaining good health by breathing air that is fresh and clean.

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