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ADAC: How dangerous is the smell of a new car?

The typical smell of a new car is insidious, as it is caused, among other things, by chemicals that evaporate after production, primarily from the plastic and glue used - literally dissolving in the air.

This process also releases substances that can be hazardous to health in certain concentrations. The German automobile club ADAC, in cooperation with the Fraunhofer Institute for Building Physics, investigated the concentration of pollutants in various vehicles and conducted a subjective assessment of the smell.

For the tests, four vehicles between 39 and 216 days old were tested in a climate-controlled measuring chamber. This chamber allows the emission of pollutants in the vehicle interior to be measured at different temperatures. Among the substances tested, total organic carbon dioxide (TVOC) is an important indicator for describing indoor air quality. TVOC include potentially harmful chemicals such as formaldehyde, benzene and xylene.

The newer the vehicle, the higher the concentration of pollutants in the interior. Although all the cars tested exceeded the reference value set by the German Federal Environment Agency (UBA) when TVOC values ​​were taken into account, none reached dangerous concentrations. In a Golf e-TSI, which was about a month old, the concentration of all hydrocarbons in the air was more than five times higher than in a vehicle of the same type that was 200 days old.

Measurements of a 116-day-old BYD Seal 6 Touring also yielded relatively high values. There is currently only a legally binding limit for formaldehyde – but even that will not come into force until 2027. In addition to the two models mentioned, a Hyundai Kona Hybrid (216 days old) and a Dacia Spring (92 days old) were also tested. All the vehicles tested were below the future limit in ambient mode – i.e. at 23 degrees Celsius.

However, when the vehicles were artificially heated, for example as if they were standing in the sun, the levels rose. The highest concentration was again measured in the new Golf. In all cases, switching on the ventilation system resulted in a significant reduction in the measured values. This is particularly important for new car buyers: if there is an unpleasant smell in the vehicle, airing it out before driving will noticeably reduce the pollutants in the air.

If an unusually strong smell persists after several weeks, buyers can file a written complaint with the dealer. The exact age of the vehicle can only be determined from the Certificate of Conformity (COC), as this document records the date of the final inspection at the factory. The vehicle registration document usually only shows the date of first registration. However, depending on how long the car has been in storage, this date can differ from the date of manufacture by several months.

New car smell...The new car smell is a scent that is commonly encountered in the interiors of new automobiles and other vehicles. The smell is caused by gases emitted from various manufactured materials, such as leather, plastics and textiles. Some people find the smell pleasant, which has led some automobile manufacturers to mimic the desired scents and utilize them to attract customers in show rooms. However, concerns have been raised about the potential health risks of the chemicals associated with new car smell. For example, a study in 2023 found that formaldehyde and acetaldehyde gases exceeded Chinese government safety standards in new car interiors, and researchers recommended that new car owners drive with windows open.

Chemical composition...Both the scent and its origins vary among different kinds of cars, depending on the materials found in the interior—for example, leather versus cloth seats. Typically, however, most of the interior of an automobile consists of plastic held together with a number of adhesives and sealers, and such materials are known to release volatile organic compounds via off-gassing. These fumes are generally attributed to mixtures of many different gases as well as plasticizers, (although DEHP, widely used in PVC, is not very volatile).

Researchers tested more than 200 U.S. vehicles of model years 2011–2012 for chemicals such as organobromine compounds (associated with brominated flame retardants, or BFRs), organochlorine compounds (e.g., polyvinyl chloride, or PVC), and heavy metals that off-gas from various parts such as the steering wheel, dashboard, armrests, and seats.

It is recommended to keep new cars well-ventilated while driving, especially during the summer. A 1995 analysis of the air from a new Lincoln Continental found over 50 volatile organic compounds, which were identified as coming from sources such as cleaning and lubricating compounds, paint, carpeting, leather and vinyl treatments, latex glue, and gasoline and exhaust fumes. An analysis two months after the initial one found a significant reduction in the chemicals. The researchers observed that the potential toxicity of many of these compounds could pose a danger to human health.

In a 2005 study, over sixty chemical compounds were identified inside the interiors of four tested vehicles, with the total volatile organic compound levels in one vehicle reaching 7,500 micrograms per cubic meter. Concentrations decayed by approximately 90% over a three-week period.

In some instances, the odor results from a manufacturing defect. According to official documents of Bentley Motors (BT26), an "obnoxious odor" in Bentley cars for model years 1999–2002 was traced to a rust inhibitor.[6] In some cultures, e.g. the Chinese culture, the new car smell is not considered desirable and manufacturers work to eliminate it.

Health hazards(CSIRO)...The chemicals responsible for new car smell may pose health risks to the occupants of new vehicles. A two-year study released in 2001 by the CSIRO in Australia found several health problems associated with these chemicals. CSIRO research scientist, Dr. Stephen Brown, reported anecdotal accounts of disorientation, headache, and irritation in some drivers of new cars. He measured pollutant levels in new cars that were sufficient to cause similar effects within minutes in controlled experiments by other researchers. Chemicals found in the cars included the carcinogen benzene, two other possible carcinogens cyclohexanone and styrene, and several other toxic chemicals.

A more recent study in Japan found that the volatile organic chemicals in a new minivan were over 35 times the health limit the day after its delivery. After four months, levels had fallen under the limit, but they increased again in the hot summer months, taking three years to permanently remain below the limit. The limits were set by the Japanese health ministry in response to more car owners suffering from sick building syndrome. A Daily Telegraph article on the study described the enjoyment of new car smell as "akin to glue-sniffing".

However, another study showed no toxicity from new car odors in lab grown cells. The odors did trigger an immune system reaction.

The most common side effects of the new car smell are headaches, sore throats, nausea, and drowsiness.

The smell of a new car is considered dangerous because it is a cocktail of toxic chemicals released by the vehicle's interior materials. While many people associate the scent with luxury, it is actually the result of a process called off-gassing, where volatile compounds evaporate into a small, enclosed space.

The Chemical Breakdown...The signature scent is made up of dozens of Volatile Organic Compounds (VOCs). These chemicals leak out from materials like plastics, polyurethane, synthetic fabrics, leather treatments, sealants, and heavy adhesives used during manufacturing.

The most hazardous chemicals commonly found in this mixture include(below):

Benzene: A known human carcinogen used in plastics and nylon, which can also cause immediate dizziness.

Formaldehyde: A highly toxic chemical used in molded parts and fabrics, linked to respiratory irritation and cancer.

Toluene: A solvent found in paints and glues known to impact the central nervous system.

Styrene: A compound used in synthetic resins and rubber that can cause neurological side effects.Health Risks

Health risks...A study by the Beijing Institute of Technology found that the combination of VOCs in a brand-new car can create an indoor environment that significantly exceeds safe national air quality limits.

Short-term effects: Exposure in an unventilated cabin can quickly trigger headaches, dizziness, nausea, sore throats, and allergic reactions.

Long-term risks: Research from institutions like the University of California, Riverside indicates that spending even 20 minutes a day in a high-VOC environment can significantly elevate long-term cancer risks and cause reproductive or developmental issues.

How to protect yourself...Fortunately, off-gassing naturally decreases over time, dropping roughly 20% each week after production. You can lower your exposure with a few simple steps(below):

Roll down the windows: For the first six months, drive with the windows cracked to flush out trapped gases.

Avoid the heat: Heat accelerates off-gassing. If your car has been sitting in the sun, open all the doors and let the cabin air out for a few minutes before stepping inside.

Use the "fresh air" setting: Keep your AC setting on fresh exterior air intake instead of recirculating the contaminated cabin air.If you are currently driving a brand-new vehicle, let me know how old it is and how much time you spend inside it daily. I can give you more specific advice on how to accelerate the air purification process.

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