‘Understanding The Relationship Between Health And Humidity Is Key To Optimising Indoor Air Quality’
Condair ‘Brand Leader’ Interview Podcast – Transcript to support learning
Every effort has been made to flawlessly transcribe the interview to support learning but please consider the recorded audio of the interview as the actual source of information for learning purposes.
Hi this is Mick de Leiburne for BusinessNet Explorer – and welcome to a special edition of our ‘Brand Leader’ interview series.
Well, due to the COVID pandemic, management of ‘indoor air quality’ – has never been a hotter topic – and there has been – much talk about the need – for ‘increased ventilation’ in buildings – to help combat the spread of viruses. With me today is Dave Marshall-George, UK Sales Director at Condair, who is here to discuss – another important, but less understood aspect of air quality management – that of ‘low indoor humidity’.
Dave joins us on the phone…
So, Dave, what impact does ‘low humidity’ have – with regards to maintaining a ‘safe indoor environment’?
Hi Mick, thanks for inviting me in to discuss this today.
Well, the humidity level of the air inside our buildings has a great deal of influence over how airborne viruses behave and how our bodies deal with them.
I think most of us are now familiar with the fact that people release viruses in droplets when we talk, breathe or cough. And also the fact that the smaller these droplets are, the longer they float in the air and the further they can travel.
How does the indoor humidity level affect the droplets?
Well, if a room has a low air humidity, below 40%RH, these floating droplets will shrink through increased evaporation. So low indoor humidity results in more droplets small enough to float around in the air, which subsequently increases the risk of infection to anyone in the room.
The second effect humidity has on airborne viruses is connected to their survival time. Airborne viruses, such as the flu, have a limited duration when they remain infectious. Many studies have shown that humidity is a major factor in this survival time and that when the humidity is lower than 40%RH, this infectious lifetime is much longer than when humidity isabove 40%.
And lastly, and I think most importantly, is the effect dry air has on us and our bodies. Our first line of defence against airborne pollutants is a process called mucociliary clearance. Mucous in the nose and throat capture airborne pollutants as we inhale them. It thentransports them to our digestive system, where they are destroyed. In low humidityenvironments, this natural defence mechanism is impaired, as our mucous membranes dry. This leaves us much more susceptible to airborne infections.
How would you summarise the effect that low humidity in a room has to health?
So, in summary, dry air below 40%RH allows more viruses to float around in a room, it allows the airborne virus to survive for longer while floating, and low humidity reduces ourbody’s natural ability to fight off respiratory infections. So low humidity is a triple threat to health.
Wow, it certainly seems like humidity is important. But if it has such a dramatic impacton our health, why don’t we know about it already?
Mick I think that’s a great question and you’re right. Even though the effects of low humidity have been well researched, it is not common knowledge. I think this is due to humidity’s imperceptibility.
We cannot see it. We cannot feel it. We can walk into a room and immediately know if the airis hot or cold. But with humidity, we have no sensory organ that tells us if the air around us is too dry.
And due to this invisible nature, society is simply not well informed about the negative effects of low humidity. But as a society, we suffer the consequences of low indoor humidityevery winter.
What happens because of low humidity in the winter?
It is widely accepted by the scientific community that low indoor humidity is a significant contributing factor to the seasonality of respiratory infections, such as flu.
The onset of the flu season in the winter closely corresponds to when our indoor humidity is dropping below 40%RH. Cold winter air contains very little moisture, so when it is heated in our buildings, its relative humidity falls. In a building heated to 21°C, the indoor humidity can drop into the unhealthy range, below 40%RH, when it’s around 10°C or less outside. And this is the case for much of our winter.
So what can we do about it?
Humidification. Using humidifiers to add moisture to the indoor air and manage humidity within the healthy range of 40-60%RH. Just as we use heating and cooling systems to manage our temperature, humidifiers are used to proactively control a building’s humiditylevel. Humidity control in the winter is a natural, effective and non-pharmaceutical method ofmitigating the spread of respiratory infections, such as the flu and COVID.
How practical is humidification of buildings – as a solution on a nationwide scale?
Very practical. As a company, Condair does this already in thousands of buildings around the world. But it tends to be for manufacturing processes that need a certain level of humidity. Sectors such as printing, pharmaceuticals, textiles, wood or anywhere that deals with materials that are affected by low humidity.
When a manufacturer is losing money because their product is drying out, there is a clearbenefit in buying a humidifier and maintaining optimal indoor humidity, and they do it.
Is it only the Manufacturing sector where you are doing this already?
We also humidify many public buildings for the health of occupants. But it tends to be where employers are very focused on reducing absenteeism. High end offices, accommodating high earning employees, present a clear return on investment in maintaining optimum air quality to minimise staff sickness.
But we really should be humidifying places like hospital wards and waiting rooms, GP surgeries and schools. These areas are the front line in the fight against seasonal illness. Maintaining 40-60%RH in these environments should have been legislated years ago. But it takes investment, and the focus is typically on keeping costs connected to these buildings to an absolute minimum.
However, considering the gigantic cost of the pandemic on society, both at a human level and a financial one, we must invest now to improve the safety of our buildings and limit the threat of future pandemics.
What is the current guidance regarding humidity levels for public buildings?
Organisations such as the Chartered Institute of Building Services Engineers have been recommending 40-60%RH as the optimum indoor humidity for human health for years. But we need these advisory recommendations to become legislative building codes before we’ll see large scale humidification of public buildings to reduce seasonal illness and protect occupants health.
I see. I suppose that would be similar to – how ventilation of buildings is now being promoted by politicians and bodies like the World Health Organization. So how does ‘humidity control’ fit alongside ‘increased building ventilation’ Dave?
Good question. I think it’s great news that healthier levels of ventilation for buildings are now being set by politicians and the people managing our buildings. Ventilation physically removes pollutants, such as COVID, from the indoor environment. But it’s not the only strategy we should be employing to maintain a safe indoor atmosphere.
Ventilation during the winter, can in fact, dry an indoor atmosphere even more. More heat being applied to dry winter air, means even lower indoor humidity. So increased ventilation alone might be removing viruses from the air, but it will also be drying our nose and throat even more, making us physically more susceptible to infection.
So how does humidity control fit alongside ventilation? Well, in buildings with centrally managed air conditioning systems, a humidifier can be installed in the air handling unit without issue. This ensures that the building’s humidity is kept at an optimum level, along with the levels of ventilation. We do this all the time and it’s standard practise. But it does obviously need more investment.
And how about buildings where there is no centrally managed air conditioning system?
For buildings without central air handling units and ducting, humidifiers can be installed that introduce moisture directly to the rooms. These could be mobile units, wall-mounted steam humidifiers or systems that spray purified water from nozzles. The type of humidifier really depends on the layout of the building. Again it does need investment, but that’s that same as any aspect of indoor air quality management. Whether it’s heating, cooling, ventilation or humidity control. There is a cost associated, but if the cost means safer buildings, reduced infection rates, less burden on our health services, fewer unnecessary deaths and potentially avoiding lockdowns, then there certainly is an excellent return on that investment.
Thanks Dave. If there’s one message you wanted to leave our listeners with, particularly those working in the types of buildings you mentioned, like hospitals and schools, what would it be?
It would be to get to know your indoor humidity. Buy a cheap hygrometer, for just a few pounds. This is something that measures and shows you what your indoor humidity is – just like a thermometer shows temperature. If it’s consistently below 40%RH, ask your line manager or building manager what the options are for managing your indoor humidity better. If they need more information on why or how to do this, there’s plenty of info on our website at Condair.co.uk.
Well, Dave thank you again for joining us today – on this special edition BNE Product News ‘Brand Leader’ interview podcast – to discuss why ‘Understanding The Relationship Between Health And Humidity Is Key To Optimising Indoor Air Quality’
Thanks very much Mick. I really enjoyed it.
That’s a pleasure. Cheers.
For more information about Condair please go to www.condair.co.uk
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