Every day new news about the coronavirus and sometimes they are even contradictory. But there are some maxims that all experts agree on, as the virus is transmitted by people – hence the importance of washing your hands so much.
However, when it comes to analyzing what happens with air conditioning, an agreement is not always reached: there are those who say that not only is it not dangerous, but it can even be beneficial to improve the quality of the air we breathe in spaces closed and there are those who think that the key is in the recirculation of the air: a ventilation system that takes in air from outside every so often it is safer, because if there are aerosols that carry the virus, they will leave the room more easily and transmission through the air will be avoided. And in the case of recirculated air, the importance lies in the filter’s ability to remove those aerosols that could carry the virus.
What does Health say?
The Ministry of Health recommends working with exterior ventilation as much as possible and, in case of having to use devices to ‘clean’ the air, has published a series of recommendations to keep air conditioning and ventilation systems clean, taking “into account the recommendations of international agencies, professional organizations and scientific societies”. The Public Health Agency of Catalonia (ASPCAT) has also published recommendations in this line of maximizing natural ventilation and hygiene. The ASPCAT specifically suggests working, whenever possible, with devices that do not recirculate the internal air but rather work with outside air.
“In the case of air conditioners that cannot work only with outside air, if due to temperature conditions their use cannot be avoided, they must be extremely cleaned and disinfected. It is recommended to disinfect the return and discharge surface of the the equipment and weekly cleaning and disinfection of the interior of the equipment and change the filter. These frequencies can be modified depending on the hours of use, the type of users and the occupation of the space “, it reads in the text.
What does SESPAS say?
Both the Spanish Society of Public Health and Health Administration (SESPAS) and the Spanish Society of Environmental Health (SESA) influence that the virus cannot reproduce without invading human cells. For this reason, they ensure that cleaning the air conditioning ducts or changing the outdoor air filters have no practical effect, except when it should be carried out. In other words, there is no evidence that the virus reproduces in air conditioning facilities.
What does the WHO say?
“A well-maintained and operated system can reduce the spread of COVID-19 indoors by increasing the rate of air exchange, reducing air recirculation, and increasing the use of outside air. The recirculation modes (which recirculate the air) they should not be used. HVAC systems should be inspected, maintained and cleaned regularly“, says the organization in the question and answer section.
The organization also ensures that it is better to use direct ventilation than to use air conditioning. And in case of using air conditioning, it is advisable to maintain proper hygiene, which means changing the filters and cleaning the ducts.
In addition, it recommends avoiding centralized air conditioning systems and instead using independent appliances so that, in case of transmission, do not reach everywhere.
Finally, if it is possible to choose, it is better to use air conditioning with renewal, avoiding recirculation (as in a car, for example), so that we make sure that the virus does not recirculate together with the air.