The Development of Standard Methods Relating to Vehicle Interior Air Quality (VIAQ) and How to Comply With Them

Importance of the Topic

The interior air quality of vehicles has direct implications for occupant health and comfort. Emissions of volatile and semi-volatile organic compounds (VOCs and SVOCs) from trim materials can affect indoor air chemistry, pose potential health risks, and generate unpleasant odors. Rising regulatory pressure and consumer expectations for odor-free cabins drive the need for reliable, harmonized test methods.

Objectives and Study Overview

• Review the evolution of regulations limiting cabin VOC and SVOC levels.
• Describe global efforts to harmonize sampling and analysis protocols.
• Highlight key technologies used in vehicle interior air quality (VIAQ) testing.

Methodology and Instrumentation

Sampling of vehicle cabin air and emissions from interior parts relies on thermal desorption (TD) coupled with gas chromatography (GC) and mass spectrometry (MS) or flame ionization detection (FID). Air is drawn through sorbent-packed tubes (e.g., Tenax TA) or DNPH cartridges for carbonyls, then transferred via a cooled focusing trap into the GC for separation and quantitation.

• Environmental and small chambers follow ISO 12219-1 and ‑4 for whole-vehicle and component testing.
• Bag sampling (ISO 12219-2, ISO/AWI 12219-9) offers portability but is susceptible to wall losses and bag contamination.
• Microchambers (ISO 12219-3, ISO 12219-6) improve reproducibility, reduce wall effects, and enable correlations with larger-scale tests.
• Direct desorption (VDA 278) heats small samples directly into a TD tube for rapid screening.
• Instrumentation examples include the Markes TD100-xr automated thermal desorber and Micro-Chamber/Thermal Extractor.

Key Findings and Discussion

The proliferation of manufacturer-specific protocols hindered comparability of VOC/SVOC results. Divergence between ISO 12219-1 and China’s HJ/T 400 created barriers to global trade, prompting a UN informal working group and a forthcoming global technical regulation (GTR) to unify test conditions. Harmonized TD–GC methods enhance inter-laboratory reproducibility and regulatory acceptance.

Benefits and Practical Applications

• Enables consistent global compliance and simplifies trade by adopting unified standards.
• Supports material selection and design of low-emitting components for improved cabin air quality.
• Facilitates rapid quality-control screening during production and prototyping.
• Improves reliability of odor and health risk assessments for end customers.

Conclusion

Global harmonization of VIAQ test methods—through ISO standards and the forthcoming UN GTR—addresses previous inconsistencies and streamlines compliance. Thermal desorption GC techniques provide the sensitivity, specificity, and flexibility needed to monitor a broad range of VOCs and SVOCs in vehicle interiors.

Future Trends and Applications

Advances may include real-time sensor integration, miniaturized TD devices, expanded analyte libraries for emerging compounds, AI-driven data analysis, and integration with electric vehicle climate systems. Ongoing development of predictive models and digital twins will further optimize material selection for low emissions.

References

1. Xu B., Chen X., Xiong J. Air Quality Inside Motor Vehicles’ Cabins: A Review. Indoor and Built Environment, 2016.
2. J.D. Power and Associates. China Initial Quality Study, 2016.
3. GB/T 27630: Guideline for Air Quality Assessment of Passenger Cars. Chinese Ministry of Environmental Protection, 2011.
4. JASO Z125: Measurement Methods of Diffused VOCs in Vehicle Interiors. Society of Automotive Engineers of Japan, 2009.
5. HJ/T 400: Determination of VOCs and Carbonyl Compounds in Vehicle Cabins. Chinese Ministry of Environmental Protection, 2007.
6. ISO 12219 Series: Test Methods for Vehicle Interior Air Quality, ISO, 2012–2017.
7. ISO 16000-6: Determination of VOCs by TD–GC/MS or FID. ISO, 2011.