There is something distinctly special about the scent of new leather, plastic and something else you cannot quite put your finger on in the cabin of a new car. In fact, this scent is so popular that there is a whole market for air fresheners and sprays that promise to return the “new car smell” to any aging vehicle.

Unfortunately, the smell that we associate with the excitement and luxury of new cars is caused by a not-so-luxurious process called off-gassing. When you smell that “new car” scent, you are actually inhaling a variety of chemical compounds that may be harmful to your health. Below, we discuss what new car smell is made of, whether you should avoid “new car smell” sprays, and how to protect the interior air quality of your vehicle.

Why is new car smell so bad for you?

There is no single culprit behind the smell that most of us associate with new cars. The scent is a combination of chemicals that off-gas from the different components in a car’s interior, such as the steering wheel, seats and dashboard. During the car manufacturing process, a variety of volatile organic compounds (VOCs) become trapped in different parts of the car. Throughout the lifetime of a vehicle, the interior components release these carbon-based chemical compounds through a process called off-gassing.

When you get into a car and take a deep breath of that enticing new car smell, you could be inhaling hundreds of toxic chemicals that are off-gassed by the different parts of the car’s interior. Products tend to off-gas the most soon after they are manufactured, which is why we associate this particular smell with newer vehicles.

Many products, including mattresses, paint and carpets off-gas VOCs that can accumulate into potentially harmful concentrations in the air that you breathe. Car off-gassing is of particular concern because a car’s interior is a small, enclosed space that can quickly become filled with harmful levels of off-gassed VOCs. VOC exposure has been found to cause health symptoms including:

Eye, skin and respiratory irritation

Headaches

Nosebleeds

Sore throats

Difficulty breathing

Fatigue

Nausea and vomiting

Dizziness

Which VOCs are off-gassed in car interiors?

The Ecology Center estimates that the average American spends around 1.5 hours in their car each day. That means 1.5 hours of your time spent breathing in harmful VOCs, some of which are known carcinogens. Researchers have found hundreds of toxic chemicals that off-gas in car interiors, the main concerns being bromine, lead, chlorine and heavy metals. These chemicals can be found in:

Adhesives and sealants used to install various car interior components;

used to install various car interior components; Flame retardants that contain bromine and antimony;

that contain bromine and antimony; Leather and fabric seats— Leather seats can contain more VOCs than fabric seats (Xu et al., 2016), possibly because they are often coated with chromium;

Leather seats can contain more VOCs than fabric seats (Xu et al., 2016), possibly because they are often coated with chromium; Dashboard, door interiors and other plastic components in a car’s interior; especially those made with polystyrene and polyvinyl chloride (PVC);

in a car’s interior; especially those made with polystyrene and polyvinyl chloride (PVC); Wood accents that are made of pressed wood or coated with a sealant.

Factors that can cause increased VOC off-gassing

In a 2016 study, researchers in China found VOCs including benzene, toluene, styrene, formaldehyde and acetone in the cabins of 16 different cars. Though the initial VOC concentrations did not exceed national standards, they were found to increase significantly under the following conditions:

The ventilation or recirculation fans were turned off;

The car had leather interiors instead of fabric;

The vehicles were newer;

The vehicles were exposed to a rise in temperature (a temperature increase from 51.8 degrees F to 77 degrees F caused some VOC concentrations to increase by 500% or more) (Xu et al., 2016).

The new car smell obviously fades over time, as do the VOCs present in the air inside of your car. However, because heat can speed up off-gassing, you may notice that the new car scent becomes stronger on hot days.

Consider this before bringing back that new car smell

Though it may be tempting to search for ways to make your car seem newer, “new car smell” sprays can come at a high cost to your vehicle’s indoor air quality. The smell that we associate with new cars is actually a combination of chemical compounds being off-gassed by its components, so what does that mean for “new car smell” sprays and fresheners?

One popular spray, Ozium, is often used to reintroduce the new car smell back into an older vehicle. The spray contains two active ingredients, triethylene glycol and propylene glycol. These ingredients are generally accepted as safe by the CDC when used as directed to kill bacteria, but they only make up a little over 8% of the spray. The other 91% of the spray’s ingredients are listed simply as “inert ingredients,” which may contain chemical compounds that are unhealthy to use in an enclosed space.

For example, one of Ozium’s “inert ingredients” (according to the Material Data Safety Sheet) is isopropanol, or isopropyl alcohol, which can irritate the eyes and upper respiratory tract. Other inert ingredients on the list are more vague, such as unnamed fragrances and an unspecified hydrocarbon propellant. Because fragrance sprays have the potential to add VOCs and other airborne irritants to your car interior, that new car smell may not be worth the potential health effects.

How to speed up off-gassing and remove the new car smell

Now that you know there are harmful chemical compounds behind the new car smell, you are probably wondering about the best way to get these pollutants out of your car’s interior. One obvious way is to open your car windows or sunroof to increase the ventilation in the car’s cabin, bringing in fresh air and allowing VOCs to exit the vehicle more easily.

But if driving down the highway with your windows down seems impractical, you can consider upgrading your car’s cabin air filters. Using a HEPA filter or a filter with carbon will offer you better protection from the pollutants in your car. Adding an air purifier to your car is also a consideration, though having good cabin air filters is probably sufficient. As with any air filter, you should change the filter regularly to maintain the product’s effectiveness.

Finally, if you are looking for a new car but are worried about the off-gassing process, things might have improved over the years. Several car manufacturers have started creating vehicles with interior air quality in mind. Try looking for cars with interiors free of PVC or brominated flame retardants and low levels of heavy metals.

Once you understand that the new car smell comes from VOCs being off-gassed inside your car, it starts to lose some of its appeal. No matter how old your car is, interior air quality should always be a priority, especially on hot summer days when off-gassing rates are highest. Fortunately, proper ventilation and air filtration can help you improve the air quality inside your vehicle.