The new car smell is ubiquitous. That certain mix of chemicals from the fabrics, foams and adhesives in your car is so well-known that there are even air fresheners designed to add the smell back to your car after it goes away. However, a new study provides some good reasons as to why you might not want to take a whiff of that famous scent.

For some background, what we know as “new car smell” is actually the result of something called off-gassing. Over time, chemicals used in pieces of the car’s interior slowly make their way into the air via this process, and that combined odor is what we smell in new vehicles.

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The study, conducted by Aalekhya Reddam and David C. Volz from the University of California Riverside, aimed to estimate at what point a person’s exposure to known carcinogens would go beyond safe levels. They based it on time spent on commuters’ trips, as well as the levels of certain chemicals detected in cars in previous studies, and found that exposure to these chemicals, mainly benzene and formaldehyde, would likely exceed what Californian health authorities consider a safe level after just 20 minutes – and that likelihood only rose with more time spent in the vehicle.

Both chemicals are on California’s Proposition 65 list of recognized carcinogens, and coincidentally, more people from San Francisco and Los Angeles had a chance of above 10% of going beyond benzene and formaldehyde cancer risk thresholds than any other location studied.

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It’s worth noting that even though something may be classified as a carcinogen, that doesn’t necessarily guarantee it will have adverse on your health, as it depends on the dose, as well as how frequently, one is subjected to it. The question, though, remains: what can be done to mitigate the dangers of exposure to carcinogens? Since not driving practically negates the point of buying a car, it’s up to the industry which, the study suggests, could substitute those chemicals with less harmful materials.