Air Quality Life

Car interior, looking like it needs a car air purifier.
Car interior, looking like it needs a car air purifier.
Left Column

Chemicals In Cars

It’s no secret that vehicle exhaust on busy roadways is a nightmare for your lungs. But it’s not just what’s coming out of tailpipes that represents a health hazard. The problem is coming from inside your car too. Many recognize it as “new-car smell.”

Vehicle interior air quality (VIAQ) – Indoor Air Quality on wheels

An emerging area of interest is gathering momentum amongst scientists, consumers, health advocates, vehicle manufacturers, and even legislators – vehicle interior air quality, or VIAQ.1

We spend around 8% of our day inside our vehicles, contributing to the roughly 90% of the time we spend indoors. Our cars are small, confined spaces that can have much higher pollutant concentrations that other indoor spaces. A movement addressing VIAQ is a natural progression extending from the growth in Indoor Air Quality concern.

Keep chemical cocktails out of the car

What is producing the alluring new car smell is a chemical cocktail emitted from parts and components in the interior of a vehicle. These interior parts include dashboards, seat coverings, flooring materials, carpeting, door trim, window sealant, arm rests, and many others. Indeed, most interior components are made with plastics, adhesives, fabrics, and other materials that “off-gas” chemicals ((think evaporation, but with chemicals instead of moisture). 

Numerous studies have found that new vehicles typically have the highest concentrations of chemicals. Depending on the vehicle tested, researchers have consistently found between 30 and 250 types of volatile organic compounds (VOCs), including several identified as potentially toxic to humans, including:

  • Benzene: Classified as a Group 1 carcinogen (“carcinogenic to humans”) by the International Agency for Research on Cancer, or IARC. Used in the manufacturing of chemicals that are used to make products such as plastics and solvents, exposure to benzene has been associated with increased rates of leukemia, lymph cancer, and blood cancer. It is extremely dangerous when inhaled and exposure can also result in eye, nose, and throat irritation.  
  • Formaldehyde (Group 1): Used in the production of adhesives that are then used in fiberboard and particle board. It is also found in foam insulation and textile finishing treatments. It has been associated with lung and nasopharyngeal cancers. It can also cause coughing, wheezing and chest pains, as well as eye, nose, and throat irritation.
  • Ethyl benzene (Group 2B - “possibly carcinogenic to humans”): Primarily used in the production of styrene. Exposure is associated with acute respiratory effects, such as throat irritation, irritation of the eyes, and neurological effects like dizziness.
  • Acetaldehyde (Group 2B):  Irritation of the eyes, skin, and respiratory tract. At higher exposure levels, erythema, coughing, pulmonary edema, and necrosis may also occur.
  • Styrene (Group 2B): produced from a combination of benzene and ethylene and is used to manufacture plastics, resins and synthetic rubbers. styrene can produce central nervous system symptoms such as decrease coordination and concentration and impairment of short-term memory. Styrene exposure can also produce irritation of the eyes, skin, nose, and the respiratory system, and can cause sleepiness or unconsciousness.
  • Toluene (Group 3 – not classifiable): Additive found in vehicle fuels, in paints, varnishes, and glues, as well as in the production of other chemicals. Toluene is classified in the European Union (EU) as a reproductive toxicant, and is also associated with many neurological effects, from muscle weakness, tremors, and impairment of speech. Dermal exposure to toluene can cause skin irritation and blistering.
  • Xylene (Group 3): Xylene serves as a solvent in paints and inks. It is also used in the production of plastics, leather, and rubber. Exposure to xylene may cause liver and kidney damage and can also result in dizziness, headache, or confusion. Skin contact with xylene can cause irritation and discoloration, as well as dryness, cracking, and blistering.

Studies find that VOC types and concentrations depend on many factors. It seems the most important include:2

  • Interior materials
  • Vehicle age and interior temperature 
  • Ventilation and humidity levels

The journal Indoor and Built Environment reviewed more than 90 relevant studies performed across over 10 countries. Some of their key findings include:

  •  In-car emission concentrations of ethanol types in 6 vehicles with leather upholstery were higher than those with fabric upholstery in 95 vehicles.
  • In-car concentrations of airborne ketones, furans, styrene emitted from leather steering wheels in 35 vehicles were higher than those with polyurethane steering wheels in 66 vehicles.
  • In-car VOC levels in new cars with sunroofs caused total VOC concentrations to increase by as much as 30%. This is due to emissions from the sealing materials and adhesives around the sunroof.
  • The use of black and white fabric upholstery could add more than 30% of the compounds measured inside cars.
  • Aromatic hydrocarbon pollution could increase with a rise in in-car temperature or humidity but decrease with car age or travel mileage.
  • The concentrations of benzene, toluene, xylenes and ethylbenzene were higher in new vehicles than in old vehicles by 12.89%, 103.54%, 123.14% and 104.20%, respectively.
  • The benzene concentration in vehicles at 29°C was about 28.8% higher than that at 24°C .
  • The 6°C temperature difference from 29°C to 35°C could lead to an increase of 102% of in-cabin benzene concentration. The magnitude of this concentration increase was much higher than the increase seen at the lower temperatures.
  • The health risk from in-car pollution was higher for drivers than passengers due to their more direct exposure to emission sources. 

Why is the “new-car smell” so alluring?

If the smell of a new car is toxic, why do we like it so much? 

The Smell and Taste Treatment and Research Foundation explains that, for most people, buying a new car is a rush.3 The scent causes us to feel those emotions again. The Foundations says that an odor is not inherently “good” or “bad.” It is the emotional response we pair with an odor that is the determining factor. 

How to protect yourself from VOCs inside your car

  • Take an extended sit behind the wheel as part of your test drive to see if your symptoms are triggered if you are especially sensitive to chemicals
  • Keep car interiors well ventilated, especially during the first six months of ownership
  • Park in the shade with the windows open when it’s safe to do so, or at least try to air it out before getting inside — especially on hot day
  • Avoid sitting in the car while it is parked
  • Use a windshield solar shade to minimize heat buildup
  • Frequently wipe down your car interior with a microfiber towel and a non-toxic cleaner
  • Use an in-car high-powered air purifier—very few car manufacturers include a truly effective air filter, especially one that can stop gases and chemicals. Additionally, standard car filters only filter outside air coming into your car. Pollutants can enter through many other areas of the car. Furthermore, a filter that only addresses air coming from outside does nothing for the air that is already inside the car. Specifically, it will never filter the VOCs and other chemicals off-gassing from the car interior. That’s why you need an air purifier that filters that air inside your car. The Atem®Car Air Purifier by IQAir is by far the most effective on the market.

Many of us need vehicles to get where we’re going. By taking steps to protect ourselves, we can arrive with our health intact.

Air Quality Life is brought to you by The IQAir Group, the world’s leading innovator of Indoor Air Quality solutions since 1963. This online publication is designed to educate and inform the public about the latest research and news affecting indoor and outdoor air quality.

Article Resources

[1] Brodzik K, et al. (2014). In-vehicle VOCs composition of unconditioned, newly produced cars. DOI: 10.1016/S1001-0742(13)60459-3

[2] Faber J, et al. (2014). Comparison of air pollution by VOCs inside the cabins of new vehicles. DOI: 10.5539/enrr.v4n3p155

[3] Moran T. (2000). The Mysterious human sense of smell: So primitive and so powerful. https://www.nytimes.com/2000/05/14/automobiles/the-mysterious-human-sense-of-smell-so-primitive-and-so-powerful.html

Right Column