What do we do when a “NOT OK” appears in automotive emissions requirements?

In the automotive sector, manufacturers establish quality requirements for the materials used in the vehicle interior to ensure that all components inside the cabin are safe, durable, and meet the comfort standards expected by users.

One of the aspects that has received the most attention is the control of volatile organic compound (VOCs) emissions. These compounds—present in plastics, adhesives, coatings, foams, and textiles—can be released into the vehicle’s interior air, affecting:

• Occupant safety and health, since some VOCs can have irritating or toxic effects.
• Driving experience, as they influence the perceived odor inside the cabin, a factor that directly impacts customer satisfaction.
• Brand image, because a strong or unpleasant interior odor can create negative perceptions of quality, regardless of the vehicle’s compliance with other technical specifications.

Sometimes, tested materials do not meet the emission limits set by manufacturers. Although this result could be an obstacle, it does not necessarily mark the end of the project. In fact, it represents an opportunity to identify the cause of the issue, implement improvements, and optimize the material or production process.

Identifying the source of VOCs

The first step when emission limits are exceeded is to understand which compounds are responsible and where they come from.

In plastics and polymeric materials, the main sources include:

• Nature of the polymer: residual monomers, oligomers, or degradation products generated during its life.
• Additives: plasticizers, antioxidants, stabilizers, pigments, or slip agents that, under certain conditions, can migrate and be released as VOCs.
• Processing conditions: excessive temperatures, prolonged cycle times, multiple reprocessings, or UV exposure can induce secondary reactions that generate undesirable compounds.
• Recycled material: incorporating recycled polymers adds complexity, as they may contain residues from previous use (fragrances, oils, contaminants) or generate secondary products during reprocessing.
• Storage and handling: humidity, sunlight exposure, oxidation, or contact with other materials can alter polymer behavior and trigger additional emissions.

This initial analysis is key to making informed decisions.

Advanced detection and identification techniques

At AIMPLAS, we have specialized laboratories for emissions and odor analysis, equipped with the necessary technology to characterize the compounds responsible for a “NOT OK” result. Among the techniques we use are:

• Gas Chromatography–Mass Spectrometry (GC-MS): enables separation, identification, and quantification of VOCs present in a sample, even at very low concentrations.
• Sensory testing under OEM standards: each Original Equipment Manufacturer (OEM) has specific requirements that must be met for the approval of a given material or component.
• Analytical Pyrolysis (Py-GC/MS): consists of heating the sample in the absence of oxygen to decompose it into volatile fragments, which are then analyzed by GC-MS. This technique is particularly useful for:
  • Identifying the polymer composition.
  • Detecting degradation products that may become VOC sources during the material’s lifespan.
  • Evaluating the impact of different processing or reprocessing conditions on material stability.

The combined use of these techniques provides a comprehensive understanding that goes beyond numerical results and helps assess how emissions affect the real user experience.

From identification to solution

When excessive emissions are detected, our approach is to support the client throughout every stage of the process:

1. Accurate detection and identification of the responsible compounds.
2. Localization of the emission source, whether it is the polymer, an additive, processing conditions, recycled content, or storage factors.
3. Design of practical solutions, tailored to the client’s and project’s needs, such as:
   • Optimization of processing conditions (time, temperature, cycles).
   • Selection or substitution of additives for more stable, lower-emission alternatives.
   • Evaluation of alternative raw material suppliers.
   • Choice of alternative materials with a lower tendency to emit VOCs.
   • Review of logistics and storage conditions.
4. Validation of the solution by repeating tests to ensure that the part or material meets the automotive manufacturer’s specifications.

This comprehensive approach not only resolves a specific issue but also implements long-term improvements in product quality and process efficiency.

Common scenarios

Although each project is unique, at AIMPLAS we have helped several companies successfully overcome “NOT OK” emission results. Common examples include:

• Materials that presented or developed an unpleasant odor.
• Interior parts with adhesives emitting certain volatile substances.
• Use of recycled polymers containing fragrance residues that produced unfavorable results.
• Materials with surface treatments releasing detectable volatile compounds.

Trends and future challenges

Emission control inside vehicles is a continuously evolving field. The main trends shaping its future include:

• Stricter regulatory requirements: both in Europe and other international markets, emission limits are being progressively reduced.
• Increased use of recycled and sustainable materials: the transition toward a circular economy is a priority, but it poses additional challenges for controlling unwanted emissions.
• Advances in analytical techniques: instruments are becoming more sensitive, allowing detection of compounds at extremely low concentrations.
• More demanding consumers: perceived quality in vehicle interiors is a key differentiating factor, and aspects such as odor are now more important than ever.

Conclusion

A “NOT OK” result in emission tests should not be interpreted as a failure, but as an early warning that allows corrective action before the problem reaches the market.

At AIMPLAS, we offer companies:

• Equipment for emission characterization and analysis.
• A multidisciplinary team of experts in plastic materials, transformation processes, and automotive standards.
• Proven experience in national and international projects.
• Accreditations and approvals that ensure the validity and reliability of our results. Our laboratories are approved by Volkswagen, Renault, and Daimler.

In this way, we help companies in the sector to transform an unfavorable result into a competitive advantage, improving their materials and ensuring success in the demanding automotive market.