Chemicals of Emerging Concern Emitted from Water-Based Paints: Experiments and Modeling

Water-based paints, despite being marketed as environmentally friendly, emit various chemicals of emerging concern (CECs) that may pose health risks indoors. This study characterizes CEC emissions from water-based paints through systematic experiments and modeling. Four CECs, covering a broad range of volatility, were tested experimentally. Results showed distinct emission patterns for chemicals with varying volatility: high-volatility CECs, like diethylene glycol butyl ether, exhibited rapid peak-and-decay emissions, while low-volatility triethylene glycol bis(2-ethylhexanoate) showed persistent emissions over 100 days. A dynamic mass transfer model was developed and validated against experimental data. The partition coefficient between polymer particles and air (K_pa) and the diffusion coefficient within the polymer (D_p) were identified as the key parameters governing emissions. The model classified emissions of 20 common CECs into short (<10 days), medium (10-100 days), and long-term (>1000 days) profiles, highlighting prolonged exposure risks for low-volatility compounds. Substrate effects showed that permeable substrates reduced initial emissions of volatile CECs but had minimal impact on long-term release. The model was applied to a residential indoor scenario, demonstrating its utility for exposure assessment. These findings improve the understanding of CEC emissions from water-based paints and provide valuable insights for more accurate risk assessments and safer product design.