Spanish scientist explains Covid contagion: “Imagine it's like invisible smoke”

ONE of Spain's top scientists and key experts in viral contagion has warned the public to look out for a seemingly-harmless habit before walking into a shop or other closed building.

Dr José Luis Jiménez, professor in chemistry at Colorado University (USA), says anyone about to enter a premises, or even taxis or other forms of public transport, should keep their wits about them and watch what those inside do before they go in.

During an interview on the US-based Radio Cut, Dr Jiménez recalls how Covid-19 is transmitted via droplets expelled when breathing, talking, shouting, singing, coughing or sneezing, and which hang around in the air for up to 'an hour or two' – notwithstanding the possible, albeit much lower, risk of contagion through surface contact.

For this reason, ventilation is key, so the contaminated droplets can 'float out'.

“What's most dangerous, and gives rise to many cases of contagion, is when people are breathing the same air in the same room for a while,” Dr Jiménez explained on the radio.

He refers to shop premises, with or without air conditioning, as an example.

“Maybe you're in a shop or a taxi and you see the people inside putting on their mask or other face-covering because they've seen you come in,” he says.

“But the air inside is already full of viral particles and, if your own mask isn't on tight enough or isn't of very good quality, you'll breathe them in and could become infected.

“So if you're about to walk into an enclosed area and you see someone inside with their mask off or pulled down, don't enter – even if you see them putting it back on properly just before you do so.”

He actually goes one step further and tells the public to 'run for it'.

To understand how it works, Dr Jiménez used cigarette smoke as an example.

“Cigarette smoke does not just fall to the ground, and it doesn't come out as a projectile – it comes out and hangs around in the air; how long it stays there and in what concentration depends upon how well the room is ventilated. 

“You need to imagine that the Covid virus is an invisible smoke being exhaled by other people, and take action to ensure you inhale as little of it as possible.

“For this reason, ventilating closed spaces is crucial, but it's even more important to do as much as you can in the open air – that's even better than ventilating.

“Where you absolutely have to be in an enclosed space, as well as ventilating, spending less time there and with fewer people, make sure your mask is properly fitted.”

In Spain, masks are compulsory anywhere outside the home, even in communal areas of apartment blocks, and even outdoors, whether or not it is possible to keep a wide distance between oneself and others.

Medical exemptions do not apply, although if a person does have a respiratory or other condition that makes it extremely uncomfortable or dangerous to wear a mask, they will be expected to prove it by showing a note from their doctor that explicitly states this is the case – and will not be allowed into any shop, bar, public transport or other enclosed communal space.

Hefty fines apply to anyone who does not wear a mask, although social and public pressure is normally enough to convince those very few who might decide not to do so.