Auto interiors made healthier with lower VOC emissions
What do you think of when you hear ‘new car’? Big chance it’s that ‘new car smell’ springing to mind right now, this smell of a brand new, pristine interior. You are not the only person to do so. A large part of American (86%) and European consumers (69%) find the new car smell appealing. Many are convinced that different car brands have distinct smells (Lindstrom, 2008). Unfortunately, we’re going to ruin that experience for you here, as we tell you more about VOCs.
By the way, the thing about distinct smells is partly true. Various brands have used odor sprays to enhance the sensory experience of a new car.
Cultural differences and VOCs
The way we perceive the ‘new car smell’ varies widely. Particularly American consumers love it so much that they restore it with interior perfumes and sprays. On the other hand of the spectrum are Chinese consumers who will not buy a car with a distinct smell, according to research by J.D. Power (2017). The reason is embedded in Chinese consumer culture and the nature of the new car smell, which stems from volatile organic components (VOCs). The presence of which can sometimes be noticed in fogging of the windows and a distinct smell when stepping into the car.
These are organic chemical compounds that easily become vapors or gases at regular room temperature. Chinese consumers are, according to various surveys, more concerned about VOCs and hazardous substances. They associate the odor in a new car with health risks. VOCs are all around us and occur naturally (think of food and flowers) and synthetically (cleaning products, paint thinners). They are a large part of our sensory experience of the world around us. Yet, though these occur everywhere, high concentrations of VOC emissions have been associated with various health issues, which explains the concern about them.
VOCs in car interiors
Automotive cabins are enclosed spaces that often see an increase in warmth. This accelerated process of off-gassing is more strongly present than it would be in one’s home or workspace. Over 60 different VOCs have been detected in car interiors. These come from plastics, moldings, carpeting, upholstery, adhesives, lubricants, gasoline, and leather and vinyl treatment. Some common compounds found in car interiors are toluene, ethylbenzene, styrene, alkanes, xylenes, and trimethyl benzenes. Though research has not seen much toxicity in car interiors, new cars can still cause problems like headaches and irritations (Chien, 2007).
Plastic materials, in particular, emit VOCs because often they are kept flexible with plasticizers. These are also used in coatings that need to retain their flexibility. When vinyl seats, for example, start to crack, the plasticizers (phthalates, a carcinogen) have been depleted. Where plastic materials inherently have an issue concerning VOCs, leather is a slightly different matter as its base material is organic. Due to coating and treatment, leather is emitting VOCs too. Surfaces require solvents, which off-gas over a long period, and automotive leathers, in particular, require these to give them their organoleptic qualities. Yet, comparative research has shown leather interior elements emit significantly fewer VOCs than plastics (Faber et al., 2014). New methods of leather treatment and coating show that the number of VOCs can be significantly reduced with different chemical formulations and other solvents. Water-based and bio-based chemicals are making a world of difference, also for plastics.
VOC standards and measuring methods
The general opinion is that VOCs are bad. As they can cause health issues, this is something to respect. The challenge for OEMs is a lack of universal standards, so many OEMs set their own. VOC emissions in Europe are subject to the Paints Directive (Directive 2004/42/CE) and testing methods have been standardized, either by the industry or international ISO standards (ISO 12219). The German VDA (Verband der Automobilindustrie) also developed various testing methods that set a high standard. However, as compliance is key, most producers will look towards the Chinese standard GB 27630. China has stringent requirements and is one of the largest car markets in the world.
An example of a testing method is the 10L Bag Method (ISO 12219-2). Here one uses a 10-liter bag to determine aldehyde and ketones emissions, both substances with a low boiling point. By heating the bag for two hours at 65°C, without oxygen change, the amount of VOCs can be analyzed using High-Performance Liquid Chromatography (HPLC) or Thermal Desorption-Gas Chromatography-Mass Spectrometry (TD-GCMS).
Towards better in-air quality for vehicles
The push for the Chinese market means good news for the in-air quality of our cars, as OEMs and manufacturers strive for lower VOC emissions in interiors. For years, Ford used experts to ‘sniff out’ offensive smelling car parts and even developed a technology to bake-out volatile compounds. Mazda has claimed a reduction of their overall VOC reductions by 78% with their paint technologies. These examples show the industry is driven towards further limiting the number of VOCs. Leather may play a vital part in this as an already sustainability option.
- Domestic and International Brand Vehicle Initial Quality Gap Continues to Narrow, J.D. Power Finds (2017, 28 September). Retrieved from: jdpower.com [Accessed: 5 June 2020]
- Lindstrom, M. (2008) Brand sense: Sensory Secrets Behind The Stuff We Buy. Simon and Schuster
- Chien, Y. (2007) Variations in amounts and potential sources of volatile organic chemicals in new cars. Science of the Total Environment. Retrieved from: doi.org [Accessed: 5 June 2020]
- Testing the VOC emissions of flexible materials in car interiors: How Stahl measures VOCs in products using VDA system testing. (2018, 22 November). Retrieved from: automotive-iq.com [Accessed: 5 June 2020]
- Directive 2004/42/CE of the European Parliament and of the Council of 21 April 2004 on the limitation of emissions of volatile organic compounds due to the use of organic solvents in certain paints and varnishes and vehicle refinishing products and amending Directive 1999/13/EC
- Cha, Yingying. (2019). In-cabin VOCs: Sources, health effects, and control methods. 10.13140/RG.2.2.23935.15521. Retrieved from: researchgate.net [Accessed: 5 June 2020]
- Truong, A. (2018, November 2018) Ford’s found a way to appease Chinese consumers who hate the new-car smell. Quartz. Retrieved from: qz.com [Accessed: 5 June 2020]
- Packing Heat: How Ford’s latest tech helps police vehicles neutralize COVID-19 (2020, 27 May). Retrieved from: media.ford.com [Accessed: 5 June 2020]
- Faber, Joanna & Brodzik, Krzysztof & Golda-Kopek, Anna & Łomankiewicz, Damian & Nowak, Jan & Swiatek, Antoni. (2014). Comparison of Air Pollution by VOCs Inside the Cabins of New Vehicles. Environment and Natural Resources Research. 4. 10.5539/enrr.v4n3p155. Retrieved from: researchgate.net [Accessed: 5 June 2020]