At the end of October, an article from El Pais – a Spanish-language daily – began to circulate online. It was an immersive piece on the subject of coronavirus transmission, taking the reader to a people-filled home gathering, a bar, and a classroom, showing not the science of droplets or distancing, but the impact of aerosols on spread.
Based on a tool developed by José Luis Jiménez, an atmospheric chemist and expert on air particles, the El Pais article illustrated how dangerous aerosols became when you are indoors. As you scrolled, more people in the illustrations became infected as invisible particles filled up these spaces. It showed how almost no amount of distancing, ventilation, or mask-wearing could prevent at least a few infections (and without ventilation, nearly universal infection) over the course of several hours.
Cut to two months later – and nine months into the pandemic – and the UK’s coronavirus numbers are spiking more than ever. And yet, you will hear next to nothing about aerosols.
When it comes to airborne transmission, most of us will know about droplets – the little water specks that explode from our mouths and land quickly on the ground (the reason behind the two-metre rule). Aerosols are less well known. While also emitting from our mouths, they are different to droplets in one crucial way: they float. They are the microscopic particles that hang around our heads in a cloud; and like a mist, they’ll continue to hang there until something blows them away.
Because of this, as illustrated by El Pais, they become incredibly potent when emitted indoors. Masks limit them, but not entirely; distancing helps, but even if on opposite sides of a room, infection is still likely after a few hours. Ventilation is the only major game changer, but to make ventilation work well, air needs to be able to flow in and out of the room at a rapid rate (almost like your living room being as airy as a marquee). They take hours to drop and accumulate faster – for every one droplet, we emit 1,200 aerosols.
For some of you, this explanation may feel redundant. And yet, a significant portion of the population (I would put money on a majority) don’t know what aerosols are or the significant role they play in transmission. An example: when I mentioned to a colleague that I was writing about aerosols, she replied that her boyfriend sprayed deodorant in their bedroom every morning and she hated the smell.
This lack of understanding presents a significant challenge when it comes to responding to the Covid crisis. People who have had coronavirus are truly baffled as to how they managed to catch it, because they wore a mask, distanced and followed official guidelines. This is not a problem of ignorance or denial, but a lack of education – and that, like so much else during this pandemic, is the fault of the government.
Little has been said since the spring about the dangers of meeting indoors, even as restrictions are tightened. They have not been given the same amount of airtime as other causes of coronavirus spread. You may hear the prime minister, Chris Whitty, or Patrick Vallance mention aerosols in government announcements, and you may remember a few references from briefings early on in the pandemic (“we know this virus is transmitted by surface touch, droplets and aerosols”), but the main messages we have all heard ad nauseum on how to combat transmission are to wash your hands and keep your distance. “Hands, face, space” may be a catchy slogan, but it does not communicate “you can’t be inside with others, in really any capacity, all that safely”.
For nearly a year, we’ve been told to wash our hands and stay apart, with the implication that doing so makes us relatively safe even in indoor spaces. Even during the Queen’s speech this Christmas, NHS workers were pictured singing maskless and distanced inside a visibly unventilated church. Now we have been sternly told not to meet indoors, but without the explanation that the reason for this rule is the extreme danger of aerosol transmission.
Why is it that so many more people have heard of droplets and surface transmission, when the latter is statistically unlikely to result in you catching Covid-19? It’s not hard to think of potential reasons for the government failure to educate the public on aerosols: doing so would be to acknowledge that official messaging from the start has been off. Reluctance to warn people that meeting indoors is one of the riskiest things they can do is understandable when the Chancellor spent the summer encouraging the public to get 50 per cent off at their favourite restaurants.
But now, with a new strain ripping through the country and vaccine rollout plans proving slower than promised, it is more important than ever for the whole country to understand where every danger of viral transmission lies. While it may feel pointless to do so as a national lockdown comes into full swing across England, in fact it is more crucial now than ever, when compliance appears less reliable than it was in the spring lockdown. If people are going to break the rules, it is preferable that they do so by meeting in their garden, or with every window open in their house, or with mask-wearing and limited amounts of time indoors, rather than having dinner, maskless, in an unventilated room. Most people who break the rules make a calculation that it is unlikely to lead to them getting ill, so to be both cynical and pragmatic, it is more likely they will break rules in safer ways if they understand how risky meeting indoors truly is.
That will take a mass, national campaign, from all of the devolved governments. And it will require an implied acceptance from the government of past public messaging mistakes: that, actually, indoor gathering has always been high-risk, but was allowed by politicians for the sake of their own image, to prioritise the economy and to avoid bad publicity.
Without such acceptance and a widespread educational campaign about aerosol transmission, the grimness of these winter lockdowns may prove futile. As compliance drops and risky behaviour continues despite the rules, it won’t be because people want to let the new strain spread. It will simply be that they think they are being responsible, operating in ways the government once told them were safe. And the consequences of that behavioural trend will not be the fault of those taking risks, but of a government that failed to inform them that it was a risk at all.
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