This post will go through the techniques used to help promote offgassing of the volatile organic compounds (VOCs) in a new car.
That “new car smell” is made up of VOCs and we can speed up their release or mitigate them with a number of hacks.
Not all toxins in new vehicles are gasses (VOCs) however. We will also look at avoiding, cleaning, and sealing nonvolatile toxins like metals and flame retardants.
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1. Pick a Less Toxic Car
Makes and Models
The most recent study that compares the toxicity of vehicles across brands was in 2012. The study revealed the top picks to be the Honda Civic, Toyota Prius, and Honda CR-Z.
The worst of the bunch were Mitsubishi Outlander Sport, Chrysler 200, and Kia Soul. Though things could have changed with these brands since 2012.
Toxins of Concern in Cars
The most worrisome toxins are metals, flame retardants, and PVC followed by VOCs.
A number of cars are now free of PVC and some have cut out brominated flame retardants (though replaced with flame retardants that are just as worrisome).
Some models contain more metals than others. Metals and flame retardants are not VOCs and they have no odor. They also do not dissipate the way VOCs do. Flame retardants will continue to come out of the foam for the lifetime of the foam. Metals also are rubbed off or released over time.
Honda is still popular in 2021 amongst those sensitive to chemicals. The company puts out an environmental report every year which shows that most Honda and Acura models are PVC-free and they use low-VOC adhesives, tapes, foams, and coating materials inside the vehicles (source).
See Them in Person
If you are sensitive to offgassing you will likely want to look at a few different makes and models in person to see how you feel in them.
A 2007 study showed that interior VOC emissions varied greatly between makes models and trims and even within the same make/model/trim. (Source)
You may also want to consider a car that has been on the lot for longer and may have partially offgassed already.
Certifications for Less Toxic Cars
There isn’t a universal or widespread certification for indoor toxicity of vehicles.
TUV Toxproof certifies levels of interior vehicle toxins including heavy metals. They have not released publically what levels they are allowing. And without being able to compare that to vehicles that have not applied for this certification, it makes it hard to make much use of it. Brands that are certified include Mercedes, Volvo, Renault, Land Rover, and Jaguar.
I think this is a good idea and I look forward to having a certification like this become more transparent and more widespread.
Some fabrics in interior cars are certified by Oko-Tex Standard 100. Volvo has this certification. However, the fabric is not my biggest concern in the vehicle.
How Long Does a New Car take to Offgas?
In terms of the chemicals that are volatile and produce that new car offgassing odor, this study found a lot of variability between brands. However, after one year the VOCs were down to 1/10th the original level.
The offgassing of VOCs is not a linear process, it’s on an exponential curve. There is a sevenfold decrease in the first month of use, or about 20% per week (source). To facilitate offgassing there needs to be air movement (and heat helps a lot too).
2. Heat it and Air it Out
Heat and Air While Parked
Heat, air, and time are certainly the main ways to offgas a vehicle. You can heat it by putting it in the sun, by running the heating system, or even with space heaters (very carefully in a small space).
When you are heating materials you are releasing the VOCs and also creating new VOCs (this study explains), so make sure when you are heating up the new vehicle you are airing it out substantially at the same time so that the gasses have somewhere to go.
Windows should be open while you are heating the vehicle. Windows can also be left open anytime it’s safe to do so.
When it’s raining or otherwise unsafe to leave the windows down, I would reduce the temperature by using window sunscreens because the VOCs being released have nowhere to go.
Aim for a substantial amount of airing out with heat in the first six months.
Temperature Control and Air While Driving
When you are driving you will want to keep the HVAC on fresh air intake which reduces VOCs by diluting the air, or open the windows.
While you are driving, lower the temperature to reduce the release of VOCs inside the vehicle.
3. Deep Clean your Vehicle
Deep Clean the Seats
If you have cloth seats I would have the seats cleaned with a shampoo extraction, or possibly steam cleaned.
AFM Safecoat makes a carpet shampoo that can be used for this purpose in lieu of the more toxic products that car detailers use.
You want to use an extractor that pulls some of the chemical coatings off the fabric as well as toxins that got absorbed by the fabric when the car was brand new. You can use that on carpet floors as well.
Make sure the upholstery can dry out quickly and thoroughly to prevent mold growth. My post on preventing mold in cars goes into more detail.
To capture flame retardants (FR) you want to use a HEPA vacuum (add the HEPA filter and bags) as often as is reasonable for you. FR are constantly coming out of the foam for the lifetime of the product. They are not gasses.
Wipe Down Surfaces
Phthalates and metals are other chemicals that live in dust. Wiping down all hard surfaces alongside vacuuming is a good way to mop up these chemicals.
While other websites recommend microfibers clothes because they are particularly good at grabbing on to dust where many of these chemicals live, I would also be concerned with bringing those back into the house carrying heavy metals, phthalates, and flame retardants, and I therefore might opt for more disposable clothes, like these ones.
Although it might seem excessive to some, when cleaning up dust that contains heavy metals and flame retardants, I would wear an N95 mask. These toxins are much harder for the body to process and much more fundamental in terms of the cause of illnesses.
Clean Up Oil Residue
If there is excessive oil residue left on any car parts, you can clean that up with TSP mixed in water. Be careful not to remove lubricants that are needed for the functioning of all the door parts (and other parts of the vehicle).
3. Use Absorption Materials
There are a number of materials that absorb VOCs that can be placed around the vehicle. These are especially useful when the vehicle has to be closed up due to rain, humidity, or for security reasons.
Carbon/Charcoal. My go-to would be carbon/charcoal because it’s relatively cheap and it is effective. These bags from Amazon do help.
Baking Soda or Vinegar. Some articles have suggested putting out bowels or trays of baking soda or vinegar. Those can help. If you have them handy you can put them out for 24 hours and discard them when they are saturated. But they are not as effective as the charcoal.
Absorptive Powder for Seats. You can use the same strategy to absorb VOCs coming out of seats. You can sprinkle baking soda or zeolite powder on the seats, let it sit for 12 hours and then vacuum it up. The challenge with this strategy is that the particles like baking soda particles can get stuck in some fabrics.
Air Purifier with Carbon. While you are storing the vehicle you can also run a full-sized high carbon air purifier. Run it on an extension cord. Here is my list of the best air purifiers for high offgassing. Austin Air is my top pick.
4. Use Sealants to Block Toxins
A less common strategy in a vehicle is to use sealants. In general, you want to offgas anything with heat and air first. As sealing will by definition slow down the offgassing, meaning it actually goes on for longer.
In a car that you cannot heat and air out for any reason, this strategy can be used.
Seal the Fabric Seats. AFM makes a product for sealing in offgassing in carpet which can also be used on car seat fabric. The product AFM Lock Out is spray applied to the seats.
Seal Vinyl. AFM also makes a product called Hard Seal which can be used to seal hard vinyl components. Use three thin coats applied with a sponge. So many new make and models are vinyl free so unless you must go with one that has vinyl, I would look at those other options. I would also be sure of what the material is before going ahead to seal it.
Seal other Plastics. AFM Acrilacq can be used to seal plastic in some vehicles (and is used in Hyundai to seal in some of their plastics). Talk to Green Design Center if you are not sure which product would work best.
The idea to seal surfaces in a car came from the Non Toxic Environments Podcast.
If the plastic components contain heavy metals, which they do according to the Ecology Center report, I would use this sealing strategy.
Use Seat Covers. Plastic seat covers will block flame retardants and metals in the seals.
5. Use Air Purifiers/Filters
There are small air purifiers made for cars but you can also put a full-sized air purifier in the back seat. I will go through both options.
Air Purifiers Made for the Car
Many companies that make air purifiers make a smaller model for vehicles. These plug into the cigarette lighter:
- EL Foust car air purifier has a 60 CFM fan and 3 lbs of carbon. The CFM (the amount of air it’s cycling through it) is good for a car.
- Air Oasis Mobile Unit uses PCO and generates ions. They claim the mobile unit does not give off any ozone. The fan size is not important as this machine puts out ions. The post on PCO explains in more detail.
- IQ Air Atem Car 18 CFM, less than 1 lb of carbon.
- Other popular models are similar, the Aireox Automobile model has 75 CFM fan and 2.5 lbs carbon.
- The Amaircare Roomaid is 32 CFM with half a pound of carbon.
Using a Full-Sized Air Purifier in a Vehicle
I mentioned above that you can use a full-sized air purifier on an extension cord while the vehicle is parked. But you can also use a full-sized air purifier like Austin Air while driving.
These inverters can run an appliance up to 300 watts. Air purifiers are usually around 150 watts. You can put an Austin Air, or another air purifier on this list, on the front seat or backseat. Just make sure it’s secured down really well so it is not a flying missile in a car crash. Use the inverter to run it off the cigarette lighter.
The HEPA component can be useful for capturing flame retardants and particulates, but it’s the carbon (or other sorbent materials like potassium permanganate or zeolite) that is going to make the difference in terms of reducing VOCs.
If you are incredibly sensitive, a full-sized air purifier is the way to go.
6. Should You Use Ozone to Offgas a Car?
I would be very cautious before using ozone to reduce the offgassing of a new vehicle.
Ozone works well on specific odors – smoke and fragrance residue most notably. It helps to kill and denature mold. And I did find it useful in offgassing the new glue smell of metal trailers.
But ozone interacts with many VOCs to create some unknowns. Especially in a car where the mix of VOCs can change from vehicle to vehicle new VOCs that we can’t predict can be created.
It also leaves behind oxidation of materials, which smells horrible and can worsen things.
I have heard from folks who have had success using ozone to offgas new cars. If that works for you, carry on. But for folks new to using ozone for VOCs, I would discourage that experiment. See my post on ozone for precautions.
Myths About Offgassing Cars
Masking odors – Other websites are promoting odor masking agents to get rid of that new car smell. Please don’t add more toxic chemicals to cover up toxic chemicals.
Using the car’s cabin filter – This gets mentioned a lot too. The cabin air filter is mainly to protect the HVAC system and keep dust out.
You can add a filter with charcoal or even a HEPA filter. This minimal amount of carbon is not going to make a dent in the offgassing, and would only help when it’s on recirculate.
When you are driving the vehicle during the initial offgassing phase you want to keep outdoor air coming in as much as possible, not on recirculate.
Though it’s still a good way to help keep your HVAC system clean and keep some particulates out if you have high air pollution outside.
For those sensitive to outdoor pollutants, I would use a HEPA cabin filter. This can be especially useful if interior offgassing is forcing you to keep the air on fresh air intake and you are sensitive to outdoor pollution.
Corinne Segura is a Building Biologist with 7 years of experience helping others create healthy homes.
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