Like many issues concerning health, it’s a social problem too: those with the worst indoor air quality are probably the ones with the least capacity to do something about it. “When we’re thinking about improving our indoor environments, I think it’s really important that we think about how we enable people to get equal access to good air quality,” says Catherine Noakes, professor of environmental engineering for buildings at the University of Leeds.
If that all sounds bad, it isn’t – scientists know how to fix it. In fact, they’ve known for decades, says Noakes. And the solutions are surprisingly simple. Opening windows, for one, is a simple temporary fix, but it doesn’t solve the problem of outdoor air pollution getting in. More advanced methods include mechanical ventilation and filtration systems, such as HEPA air filters which physically remove particles and pollutants from the air.
While it’s pretty difficult to directly measure ventilation rates in a building, getting a carbon dioxide monitor is a great first step. Carbon dioxide concentration levels can act as a proxy for ventilation rates; if levels are high, then it’s likely that other pollutants are high too. In the UK, the Health and Safety Executive (HSE) sets the limit of carbon dioxide concentration in a workplace at 5,000 parts per million, or ppm, over an eight-hour period. And the HSE also has a guide to properly ventilating your office. But just because that’s the limit doesn’t strictly mean that it’s optimal or healthy – Allen’s research saw negative effects on productivity at levels below 1,000ppm.
But cleaning up our indoor air will still take time and concerted effort. “We need to recognise this is the start of probably quite a long journey,” Noakes says. We know the science, and the guidelines in place are stringent enough, but “the biggest problem is compliance,” says Noakes. And we need to figure out how many buildings aren’t compliant with the standards. Under the Management of Health and Safety at Work Regulations 1999, employers are legally required to assess the risks to the health and safety of their employees and to put arrangements in place to control those risks. But the HSE rarely does checkups or prosecutes building owners and operators, says Timothy Sharpe, head of architecture at the University of Strathclyde. “The pandemic has made us realise that we don’t really know very much about quite a lot of our buildings,” he says. “We actually have very little data on how buildings are actually performing, what their ventilation levels are like.”
But the momentum from the pandemic means this could be the time to crack down on poor indoor air quality. Allen says this is the perfect moment to focus on the other benefits that come from cleaner indoor air beyond mitigating the spread of the virus. “When Covid eventually loses centre stage in our lives, we shouldn’t go back to forgetting about our buildings,” he says.
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