Almost all car parts may emit various kinds of volatile organic compounds (VOC). PVC artificial leather, PU materials and adhesives are the main sources of formaldehyde and acetaldehyde while PP plastics, PV artificial leather, EPS and paint coatings harbor benzene-based organic compounds. Textiles and composites may also contain small amounts of formaldehyde and acetaldehyde so they can be everywhere and the widespread use of cars means people should now pay more attention to vehicle indoor air quality (VIAQ). For this reason, TUV Rheinland Greater China, a professional testing services provider from Germany, conducted a survey into VIAQ last year. Indoor air samples were taken from 51 vehicles volunteered by their owners while stationary and in motion to simulate real-world use. The air samples were then carefully tested and analyzed to provide consumers and auto makers with useful technical data. The test results found that 20 out of 51 samples failed to meet air quality standards**. 12 of the samples that passed the test while stationary failed when they were in motion.
The general public doesn’t have a clear picture of interior parts and knows little about VIAQ. In reality, more than half of interior parts are made up of artificial materials, including the dashboard, interior paneling and roof lining. Some of the plastic parts may contain hazardous substances such as benzene, toluene, xylene, and formaldehyde. Other interior fittings such as the car mat, blinds, seats, cushions and seat facings are mostly made out of artificial textiles and leathers that may contain large amounts of VOCs. The paints, solvents and adhesives used during car production tend to contain solvents such as benzene, toluene, formaldehyde, ethyl acetate, acetic acid, propanone and butanone. Having a full understanding of how interior parts affect VIAQ means TUV Rheinland offers an improved testing solution that provides a comprehensive picture of VIAQ, enabling improvements to be made.
About the Improved Testing Solution
From the above table, it can be seen that two modes are defined by TUV Rheinland: A “Static” mode simulating no movement for extended periods of time and a “Dynamic Mode” for simulating when the engine is running. The difference between the two modes is that static mode recreates the indoor pollutants emitted after the vehicle has been standing for some time (e.g. getting into the car the next morning). The emissions then come from all of the interior fittings and the test results reflect how differences in interior fittings affect indoor pollution. Dynamic mode tests for indoor pollution when a vehicle is in motion or after it was in motion. This is because the engine and other parts generate large amounts of hazardous substances while people are driving their cars. The car design may also lead to some substances entering the cabin via the ventilation system so the indoor pollution in this situation is different from the static mode.
Temperature and some other testing details are now available as options. The testing temperature for example is “23±2 degrees or level 2 of the indoor air-conditioning” which makes the test far more practical and reduces differences in test results caused by variations in vehicle design. The target substances to test for can be increased as necessary and the substances in our database allow us to identify and quantify up to 400 types of VOCs. This covers basically all common VOCs and the database is continuing to be expanded.
The sampling model designed by TUV Rheinland provides a more objective and complete reflection of the true conditions inside the cabin. This helps customers identify and solve as many problems as possible.
The TUV Rheinland Greater China technical team carries on the technical excellence of TUV Rheinland and strives to achieve perfection in all aspects of sampling and analysis. All of the equipment used in the testing is either equal or superior to the standards of test centers in Germany. In addition to German technical experts, the Chinese-born experts in the core technical team all have technical backgrounds in Germany or have studied in Germany for many years. They are therefore very familiar with all the technical details and regulatory requirements in Germany and Greater China so they can create testing plans tailored to local regulations and customer requirements.
Improving Vehicle IAQ
The main sources of indoor air pollution include: car seats, adhesives, paints and coatings, and interior textiles. Manufacturers and consumers should pay attention to the solvent types and content when choosing related materials.
Integral structures can be used instead of small parts to reduce the amount of adhesives used. This will help reduce indoor pollution from formaldehyde and acetaldehyde.
Non-spray-on plastics with high gloss or matt finish have now reached the market. The use of non-spray-on ABS, PC/ABC, PA/ABS, PA/ASA and PC/ASA materials will effectively reduce pollution by benzene-based compounds such as xylene.
In-mold inlay injection may also be used instead of spray-painting to reduce benzene-based pollutants in the indoor air.
PP and PVC artificial leather’s formaldehyde and acetaldehyde content as well as EPS foam and interior fittings’ styrene content all tend to be relatively high. Manufacturers should pay attention to their VOC content when picking what materials to use.
To download the full version of the White Paper: Optimizing test programs to fully reflect in-vehicle air quality, please click survey.tw.tuv.com/tuvsurvey/index.php?sid=188583&newtest=Y&lang=en