Though the expectation of vaccine is around the corner, we still need to wait for at least few months. Meanwhile COVID-19 will not go away by itself and it will still be with us for sometime.
It is commonly known that COVID-19 can spread through aerosol droplets for quite some distant, get attached and accumulated on surfaces for time periods that allow them to circulation in buildings by ventilation and air-conditioning systems. Though there are risks and indications that AC and ventilation systems can cause spreading of COVID-19 there are still limited, systematic detailed and comprehensive studies on the exact effects of humidity, temperature and the technical specification of filters in large central ventilation and AC system. Through the so-called ‘Memory Effects’, e.g. in Offices, Towers, Restaurants, Hotels and similar Complex Buildings. In theory, it is enough that few infected persons can cause spreading of COVID-19 in the whole building if control, considerations and precautions are not well in place. Though out-door air can be used to some extent to mitigate this problem there are still several limitations. So, degraded indoors air-quality can in itself cause serious public health issues as we still don’t have enough knowledge. Even being tested negative isn’t enough to be safe in air-flights (https://www.google.se/amp/s/www.cnbc.com/amp/2020/10/14/travel-and-coronavirus-do-pre-flight-covid-19-tests-work.html).
We are facing the threats of a second wave that may very well be much aggressive and we need to be very careful about indoors air-quality. Air-quality is definitely a serious matter that requires good sanitation in air and also how to deal with it needs to call our attention.
Few observations, literature and research articles on this matters are given here.
https://www.google.se/amp/s/nationalpost.com/health/covid-19-likely-spread-by-building-ventilation-say-canadian-researchers-working-on-an-hvac-fix/wcm/fda18c51-8cce-4640-8855-52cec5b0410f/amp/
https://nationalpost.com/health/covid-19-likely-spread-by-building-ventilation-say-canadian-researchers-working-on-an-hvac-fix
https://www.urbaneer.com/blog/can_i_catch_covid_19_from_heating_ventilation_air_conditioning_systems
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7182754/
https://www.nytimes.com/wirecutter/blog/air-conditioning-coronavirus/
https://www.businessinsider.com/turning-off-ac-could-limit-chance-of-infection-experts-say-2020-4