A strange fragment of memory cropped up each time Holly Samuelson went into the washroom at her office: high school biology class. “It happened a few times,” she says. “Then I realised it was the smell that was bringing me back.”
The memory was of dissecting a specimen preserved in formaldehyde, a suspected carcinogen that prevents decomposition. Formaldehyde is also sometimes used in glues in inexpensive wooden furniture. Samuelson, an architect, realised the bathroom cabinets were likely the source of the smell. They had probably been releasing formaldehyde fumes for some time, unnoticed by anyone except her subconscious.
Situations like this – where a potentially unpleasant substance quietly accumulates indoors – are not as uncommon as you might assume. Although we spend 90% of our time inside, the quality of the air in our offices, homes and schools can be poor, scientists have found, thanks to the release of gases and volatile compounds from furnishings, particulates from cooking, and other sources, all compounded by poor ventilation. That’s despite the fact that low air quality can interfere with workers’ productivity and lead to lower scores and more absences in schools. It’s also, in more extreme cases, been linked to “sick building syndrome”, a set of symptoms that can include headache, sore throat and nausea associated with being in a particular building.