The relationship between interior wall coatings and health and environmental protection

Environmental Performance

• VOC Content: VOC (volatile organic compounds) is an important indicator of the environmental performance of interior wall coatings. According to the international standard ISO 11890-2:2020 “Paints and varnishes – Determination of volatile organic compounds (VOC) and/or semi-volatile organic compounds (SVOC) content – Part 2: Gas chromatography method”, the VOC content in interior wall coatings can be quantitatively analyzed by gas chromatography-mass spectrometry (GC-MS). In actual testing, for example, in the comparative test conducted by the Guangdong Consumer Council, the VOC content of all 17 samples of interior wall coatings met the requirements of the national standard GB 18582-2020, that is, the VOC content should not exceed 80g/L. In addition, some developed countries have stricter restrictions on VOC content. For example, the European Union stipulates that the VOC content of Class I (matte) coatings should not exceed 30 grams per liter.
• Hazardous Substances Testing:
  • Formaldehyde: Formaldehyde is one of the common hazardous substances in interior wall coatings. According to the national standard GB 18582-2020, the formaldehyde content in interior wall coatings should not exceed 50mg/kg. In actual testing, the formaldehyde content of all 17 samples of interior wall coatings met the requirements of this standard. The detection method of formaldehyde release includes acetylacetone spectrophotometry, which involves the reaction of formaldehyde with acetylacetone under acidic conditions to form a yellow compound, and then the concentration is calculated based on absorbance.
  • Benzene Compounds: Benzene compounds (such as benzene, toluene, xylene, etc.) are hazardous substances that may be present in interior wall coatings. According to the national standard GB 18582-2020, the total content of benzene compounds in interior wall coatings should not exceed 100mg/kg. The detection method usually uses gas chromatography-mass spectrometry external standard method, which involves qualitative and quantitative analysis based on retention time and external standard curves.
  • Heavy Metals: Heavy metals such as lead, cadmium, chromium, and mercury may be present in interior wall coatings. According to the national standard GB 18582-2020, the soluble heavy metal content (limited to colored paints and putty) should not exceed 75mg/kg for cadmium (Cd), 60mg/kg for chromium (Cr), and 60mg/kg for mercury (Hg), and the total lead content should not exceed 90mg/kg. The detection methods generally include atomic absorption spectrometry (AAS) or inductively coupled plasma atomic emission spectrometry (ICP-AES).

Health Impact

• Indoor Air Quality: VOCs and formaldehyde in interior wall coatings can be released into the air, affecting indoor air quality. Long-term exposure to these harmful substances may lead to respiratory diseases, allergic reactions, and even cancer. Therefore, choosing low-VOC, low-formaldehyde interior wall coatings is crucial for maintaining indoor air quality.
• High-Risk Exposure in Special Populations:
  • Infants and Toddlers: The breathing zone height of infants and toddlers (0-1.5 meters) coincides with the peak concentration zone of wall pollutants, and their metabolic systems are not yet fully developed, with formaldehyde absorption rates being 2-3 times that of adults.
  • Pregnant Women: Exposure to benzene compounds in pregnant women may affect fetal development through the placental barrier, and formaldehyde exposure may also increase the risk of miscarriage and fetal malformations.
  • People with Allergic Constitutions: Components such as film-forming aids in coatings may cause contact dermatitis, and microbial metabolites (such as mold spores) may trigger acute asthma attacks.
• Other Functions: Some interior wall coatings have special health functions. For example, anti-mold and antibacterial coatings containing nano-silver ions can effectively inhibit mold and maintain indoor air freshness; the coating of diatomaceous earth powder interior wall coatings forms a mesh structure, which has sound absorption and noise reduction, and calming effects.

International Standard Certification

• ISO Standards: The ISO 11890 series of standards are widely recognized international standards for the determination of VOCs in coatings, applicable to the detection of VOC content in interior wall coatings. In addition, the ISO 16000 series of standards cover sampling and analysis techniques for indoor air pollutants and are applicable to VOC release testing.
• EN Standards: EN 71-3 is a European standard used to test the migration of heavy metals in coatings.
• Environmental Certification: In addition to meeting international standards, some interior wall coatings have also obtained environmental certifications, such as the China Environmental Label (Ten Ring Certification) and the European Ecolabel, which set stricter requirements for the environmental performance of coatings.

In summary, the environmental performance and health impact of interior wall coatings are of great concern. When choosing interior wall coatings, consumers should pay attention to their VOC content, hazardous substance content, and whether they meet relevant international standards and environmental certifications to ensure the health and safety of the indoor environment.