In the course of his research on the New Orleans trailer park culture that developed in the wake of Hurricane Katrina, Oxford anthropologist Nick Shapiro stumbled on something unexpected. At 250 square feet, the FEMA-issued mobile homes were scarcely fit to live in, but there was one thing about them that, for their occupants, represented the height of luxury: a scent evocative of the interior of a new car. This smell was also making them sick.

“Trailer residents would positively note the new smell of their trailer between bouts of coughing,” said Shapiro. “These trailers are potential harbingers of larger domestic formaldehyde issues that affect not just manufactured housing but many new homes in general—particularly tightly sealed ‘green’ homes.” And the toxic trailers have traveled beyond New Orleans: Since 2010, over 120,000 FEMA trailers originally intended as temporary post-Katrina housing have been bought and sold throughout the U.S.

Alice Robb: What is the “new car smell”?

Nick Shapiro: The chemical bouquet of the “new car smell” has become a part of the global sensorial palette, but its chemistry is contentious; what people identify as the “new car smell” is made up of a broad range of chemicals. If you ask the auto industry, they say it’s plasticizers, but if you run a mass spectrometry inside a new car, they only make up a small proportion compared to volatile organic chemicals. Formaldehyde is a major component, espcially in homes, where it's used as a setting agent in engineered woods like plywood and particle board.

AR: Is it dangerous?