Ah, that new car smell.
That leathery, plastic-y aroma can feel like the height of luxury.
And you’re about to be the first person to make a real butt imprint on that seat!
But this smell comes with a catch.
Some of the compounds that make a new car smell fancy
have also been known to cause cancer under some conditions.
Manufacturers are expected to test how many of these compounds
are floating in and around their vehicles, to make sure they’re at safe levels.
But buckle up: research suggests these tests might have left out some variables.
Like the Sun. And the fact that vehicles spend a lot of time outside.
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The molecules that make “eau de new car” belong to a category
called volatile organic compounds, or VOCs.
In general, VOCs are everywhere: they’re in nail polish remover,
they’re in Grandma’s antique wood furniture.
They’re in leaves, you name it.
And in terms of health effects, they’re a mixed bag.
Some have little to no known effects on human health,
and some should really stay out of your lungs.
When something releases VOCs, it’s called off-gassing, and how big of a deal
this is comes down to what compounds are doing it, and in what quantities.
In vehicles, off-gassing comes from things like glue, paint, upholstery,
and all the plastic keeping you on the road.
Since new vehicles haven’t had a chance to air out, they tend to off-gas more.
And the list of VOCs that have been detected in them
is about as long as a drug store receipt.
Studies have found anywhere from 30 to more than 250 VOCs in vehicles,
and some common ones include styrene, acetaldehyde, benzene, and formaldehyde.
Again, different VOCs have different potential health effects.
But the four I just mentioned are all carcinogens.
Now, this doesn’t mean they definitely cause cancer.
Labels like these come from the International Agency for Research on Cancer,
and focus on how strong the evidence is that something
could cause cancer in the right conditions.
For instance, the formaldehyde and benzene in new car smell are
Class I carcinogens, or known carcinogens.
This means there’s strong evidence that they can cause cancer.
Meanwhile, styrene and acetaldehyde are Class II carcinogens.
The evidence for these compounds isn’t as conclusive as it is for the stuff in Class I.
But neither of these class labels say anything about how these carcinogens
affect your personal risk of getting cancer.
There’s a lot more that goes into that.
But remember, there are two parts to figuring out if the VOCs in new car smell
are a health risk: the compounds, and how much of them there are.
I mean, anything can be dangerous in large enough amounts,
including oxygen, and water, and even my cat, Huckleberry.
He is so fluffy, but at what cost?
So, car manufacturers are expected to figure out how many
of these molecules are usually floating around in their vehicles.
Different countries and companies have different standards for emissions
and how they should be tested.
But to give an example: one international organization requires new cars to
sit in a chamber at about room temperature, while researchers monitor off-gassing.
If the VOC levels are below safety thresholds, the car is good to go.
Except… if you’ve ever gotten into a car on a sunny day and scorched your legs
on the fake leather seat, you know cars don’t live in room-temperature bubbles.
And unsurprisingly, field studies have found that
VOC emissions can change with the weather.
Most studies have focused on the air temperature inside vehicles.
And they’ve found that when air temperatures were higher, so were VOC levels.
For instance, in a 2020 study done in China, levels of some VOCs
could be more than 100 times higher in the summer than the winter.
But you know how sometimes the air inside a car is just kind of warm,
while the dashboard is hot enough to cook a breakfast burrito?
Researchers have noticed that, too.
In one 2023 paper, scientists focused not on air temperature,
but surface temperatures inside a vehicle.
Researchers in China parked a new car outside for
12 days in the summer and took measurements as the weather changed.
They found that at their highest, the formaldehyde and acetaldehyde levels
were about 35% and 60% higher than the national standard, respectively.
Even on a cloudy day, acetaldehyde levels exceeded the limit by about 20%.
Now, this is just one car, so it could be an outlier.
But at least in this case, the researchers’ calculated that at these levels,
the total amount of VOCs imply a high cancer risk for drivers.
And this isn’t the only study to come to that conclusion.
A 2021 paper from the U.S. didn’t focus on vehicles’ ages,
but after analyzing more than two dozen studies about vehicle VOCs,
they still concluded that formaldehyde and benzene levels
were too high for California’s standards.
Because of this, they found that over 60% of local commuters
had a 10% chance of being at a higher risk of developing cancer.
Again, that doesn’t say anything about anyone’s personal risk,
just that the overall risk is higher.
So, how long does it take for VOC levels to drop?
If you’re currently Googling “new car trade-ins” in a different tab, maybe hold on.
Because it depends.
A study published in 2020 monitored VOC levels
in a new vehicle for almost two years.
They used a detection method that didn’t pick up formaldehyde, so no data there.
But for the compounds they did measure, they found that the peak level of
total VOCs had dropped almost 25% by the vehicle’s second summer.
Unfortunately, they also found that for certain molecules,
the off-gassing rates didn’t really decrease with time.
And that includes aldehydes, the family acetaldehyde is part of.
So buying a used car doesn’t solve the whole problem.
But it seems to help, as would leaving the windows open whenever possible.
And on a larger scale, it might be encouraging to know that
studies like this aren’t just for consumers.
They also inform car manufacturers and regulatory agencies,
who have the power to research and use different materials in their vehicles.
Ultimately, there can be a lot of good that comes with a new car,
especially as they become more efficient.
So, if you have the ability to buy any vehicle sitting there looking pretty on the lot,
there’s a lot to consider…including if it’s worth picking
an older model that’s had a chance to air out.
Thanks for watching this episode of SciShow,
and thanks especially to our supporters on Patreon.
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