In summer, even when it is very hot, you can use the fan without fear of risks and negative health effects, and at the same time protect the environment and the climate. This is explained by a study just published in The Lancet Planetary Health, which reassures about the use of ventilators and contradicts previous evidence – as well as international guidelines, which however are not up to date – according to which at the peaks of the heat waves these devices could cause dehydration and not be beneficial for cardiovascular health. In choosing how to cool off this year, however, we also have an additional unknown: the coronavirus and the risk of contagion. Here’s how to choose consciously and tips to prevent classic air conditioning colds.
Coronavirus, because keeping windows open is very effective
by Viola Rita
Window, fan or air conditioner?
When it is hot there are three choices: ventilate the room in a natural way by keeping the windows open, use fans or air conditioners. We know that repeatedly ventilating environments – even in cold seasons – is an excellent strategy to reduce the risk of contagion and defend, as far as possible, from the transmission of the very small particles of coronavirus that may have remained suspended in the air (aerosol). But when the temperatures are very high, only hot or very hot air enters from the windows: surely the fan is a healthier alternative also for the environment, but this tool should be used with some extra precautions during the pandemic, according to Manuele Casale, Professor of Otolaryngology at the Campus Bio-Medico University of Rome. “It may be advisable at home – underlines Casale – but it would be better to avoid it in public environments, for example in the workplace, between people who do not live together. This is because the wind produced is often direct and not diffused and the rapid movement of the air can push and convey a flow with droplets or aerosols possibly containing traces of viruses, even faster than air conditioning “.
On the contrary, air conditioning is not to be demonized and in specific situations it could even bring advantages. This is shown by a simulation conducted by a research group of the Bambino Gesù Children’s Hospital. From this study, in an emergency room waiting room, in the presence of six adults and six children without masks, if the speed of the system is doubled of aeration through a conditioner, the droplets and particles of saliva emitted in a cough are dispersed more – at least immediately, in the seconds immediately following – and the risk of contagion is lowered.
Covid reopening. Science certifies: especially open windows
by Simone Valesini
“It is better to prefer systems that draw air from the outside – stresses Casale – in order to have a change and not always ‘stagnant’ air, rather than devices that only cool the internal air”. For the same reason, recirculation in a car should be avoided if there are people not living together. “If you turn on the air conditioners – adds Casale – it is still good to open the windows periodically, at regular intervals, to further facilitate the exchange of air”.
Starting from the rules of common sense and the etiquette of using the air conditioner, it is advisable to adjust the internal temperatures so that they are not too cold. “The shared recommendations indicate to remain around 24-26 ° C and not to drop below 24 ° C – explains Casale – since below the cold can be harmful and excessively inhibits mucociliary clearance, which is a physiological process which helps to inactivate viruses and pathogens present on our mucous membranes “. More vulnerable are certainly children, the elderly, asthmatics and people with particular pathologies. “What is particularly harmful – specifies Casale – is the strong temperature difference from outside to inside. This is why it is important on the one hand to set temperatures that are not too low and on the other hand to acclimatize gradually. How? Even simply holding a scarf in front of your mouth and nose when entering cold environments. And on the unfortunate occasion of the pandemic, the mask comes in handy for this purpose “.
Another essential point is the correct maintenance of the systems. “We must not underestimate the health impact of inadequately cleaned filters – concludes Casale – given that harmful microorganisms, such as legionella pneumophila, can grow and stagnate here”. This bacterium is responsible for legionellosis, an infectious disease that affects the respiratory system and can be serious.
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