According to Christian Garzoni, an infectious disease specialist and a member of the federal commission for the preparation and management of pandemics, air conditioning systems spread the virus by moving the air around the room or simply recycling it instead of replacing it.
Even social distancing of 1.5 metres would not prevent the transmission.
“If someone sits three metres from me, air conditioning can transport the cloud of particles to my workspace,” he said.
He added that when a person infected with coronavirus speaks, coughs or sneezes, they project microdroplets up to eight metres away. This contaminated 'cloud' can remain suspended in the air for several minutes.
His expert group found that while speaking for one minute, an infected person can spread some 1,000 contaminated droplets through the air, which can stay in suspension for up to eight minutes.
“Studies show that coronavirus can be transmitted by aerosols, especially in poorly ventilated rooms”, Garzoni pointed out.
To prevent, or at least curb, the contamination through the air, Garzoni said that masks should be worn in poorly ventilated, confined spaces.
For that reason, “wearing a mask in the office is essential”, he added.
They are also required in shops in cantons of Vaud and Jura.
And last week cantons of Basel, Aargau and Solothurn, made them compulsory in all nightclubs.