health

Why stores should be checking CO2 levels to keep us safe


John Lewis boss Pippa Wicks was on the radio last week, reassuring the public. 

As non-essential retailers threw open their doors for the first time this year, the department store, she said, had started quarantining products customers had touched for ‘a couple of days’ to allow for ‘decontamination’.

While others didn’t claim to be going that far, a quick dash around London‘s West End on Wednesday afternoon threw up a raft of other changes in shops: hand sanitiser stations everywhere, bouncers limiting numbers of customers going in – meaning queues snaking up and down the streets – universal mask-wearing, social distancing reminders over Tannoy and plastic screens galore.

Granted, we had many of these things by last summer. But there’s even more of it all now. 

A friend told me he was required by his local InterSport branch to put on plastic gloves, and plastic foot covers, before being allowed to try on some trainers. 

A John Lewis partner cleans the Charlotte Tilbury counter at the Peter Jones store in Sloane Square, Chelsea, London

A John Lewis partner cleans the Charlotte Tilbury counter at the Peter Jones store in Sloane Square, Chelsea, London

To save everyone from… foot Covid? Who knows.

Most shops, clearly unwilling to quarantine clothes, were keeping changing rooms firmly closed.

The measures are, no doubt, aimed at making stuff we buy as ‘Covid-secure’ as possible. But do they really?

I have my doubts, and I’m worried that focus on these things is a distraction from the real risks.

And I’m not alone. Over the past few weeks, we’ve been highlighting how many of the pandemic practices businesses now seem compelled to comply with don’t actually do much at all to protect us from the virus.

Temperature checks, one-way systems and plastic screens, and the incessant ‘medical-grade deep cleaning’ of just about everything – all have been labelled as pretty much futile by numerous experts who really know what they’re talking about.

Why? Well, mounting evidence suggests Covid is airborne. This means it can hang in the air like smoke. Indoors, it can rapidly accumulate.

And no amount of washing, distancing, and certainly no plastic screen will stop other people in that room inhaling the virus, contracting Covid, and potentially giving it to others. 

Mask-wearing will limit, to some degree, the speed at which viral particles are exhaled into the air but the key measure to protect against airborne transmission indoors, say experts who subscribe to this theory, is ventilation.

Simply opening a window might not be feasible in a large department store or shop, but these kinds of premises will have mechanical ventilation – fans and ducts that bring in fresh air from outside.

Early morning shoppers at Primark, in Birmingham, as England takes another step back towards normality with the further easing of lockdown restrictions on April 12

Early morning shoppers at Primark, in Birmingham, as England takes another step back towards normality with the further easing of lockdown restrictions on April 12

Eager shoppers pack Oxford Street in London, England, on April 12

Eager shoppers pack Oxford Street in London, England, on April 12

When we questioned a range of retailers, most said they’d ‘increased ventilation’ in line with Government guidance. 

Effective ventilation stops indoor air stagnating and helps blow away that viral ‘smoke’ should it linger, and the official advice acknowledges this.

But how much ventilation is enough? Finding specifics on this is trickier. I spoke to University of Cambridge engineering and technology expert Dr Shaun Fitzgerald, an authority on the subject.

He explained the factors: the size of the room, the maximum number of people expected to be in it, the volume of air being supplied by the system, and the speed at which it’s pumped in (and out).

The more people, the more air that needs to be supplied, faster.

Given the limits imposed by social distancing rules, ‘most modern buildings with ventilation systems should already be adequate,’ he added. 

Problems begin if there are more people in a space than a system can cope with. 

What’s the difference… between Hodgkin and non-Hodgkin lymphoma 

Both are cancers that develop in the lymphatic system. 

Infection-fighting white blood cells called lymphocytes flow through the network, and in both diseases they multiply in an abnormal way and cause growths. 

Non-Hodgkin causes more growths in multiple parts of the lymphatic system, making the prognosis poorer than the much rarer Hodgkin, in which only B lymphocytes are affected. 

The longer we spend in a poorly ventilated space with someone else who has Covid, the more chance there is we’ll breathe in the virus. How can we tell if a space is well or poorly ventilated?

Many experts, and even the Government, now suggest one way that businesses can measure the effectiveness of their systems is by using a carbon dioxide (CO2) monitor.

CO2 is one of the main constituents of exhaled air. And, if we’re in a poorly ventilated space with other people, it builds up quite quickly. CO2 levels, say scientists, could be used as a proxy for Covid risk. 

The higher the levels of CO2, the more likely it is we will be breathing in air that’s already been exhaled by someone else – and might, therefore, be carrying the virus.

CO2 monitors give a measurement in a unit called ‘parts per million’ or ppm – this tells us how many particles of carbon dioxide there is per million air particles.

But for simplicity, we’ll just give the reading a number. ‘You’ll find the reading on a CO2 monitor is about 400 outside,’ said Dr Fitzgerald. 

‘If you’re going to spend hours in a space, in terms of Covid risk you’d want that measure to be south of 1,000. I wouldn’t want to spend more than a few minutes in a room with a reading of 1,500.’

CO2 itself doesn’t pose a risk until it reaches high concentrations in the air – a reading of 40,000 would mean imminent suffocation, while a concentration of 5,000 for many hours could cause illness.

In terms of proxy Covid risk, German health chiefs imposed a CO2 limit of 700 in classrooms. Our Government hasn’t set a specific level.

So I decided to put the shops, with all their well-meaning, but potentially ineffective Covid-safety measures, to the test. 

On Thursday, I returned to the High Street, this time armed with a CO2 monitor – and visited M&S, John Lewis, Primark, Currys, Foot Locker, JD Sports and TK Maxx. All passed the test, with readings between 600 and 800 – except for two.

In the vast Primark, Marble Arch, the reading on the first floor hit 1,300. And in TK Maxx, in Kensington High Street, the reading was 1,400 on the lower ground floor. 

Both shops were the busiest of those I visited that evening. But neither were at capacity (there were no queues outside, I just walked straight in).

It’s also important to note, all the other shops I visited were pretty empty, so it’s not a fair comparison. So what to make of all this? Well, I’m not suggesting there’s some sort of huge danger. 

At the levels I monitored, I’m told it meant that roughly every 50th breath I took consisted of air that had already been exhaled.

With mask-wearing, the virus itself at relatively low levels, and the shortish amount of time you spend in one of these stores, the risk of actually coming into contact with Covid in the air is ever smaller.

But it is a risk that should be prioritised, and removed. When I contacted Primark and TK Maxx for comment, both companies listed a vast number of hygiene and decontamination measures they’d employed to keep customers and staff safe.

My mini experiment, I think, proves that one thing they really should have been focusing harder on – the air we all breathe – they’d neglected. It’s a simple fix, too.

If Covid is airborne – and it is – then checking CO2 levels, and turning up the ventilation should be top of the priority list.

And please, stop all this unscientific, unnecessary, time-wasting quarantining clothes and washing shopping madness.



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