Improved C-history method for rapidly and accurately measuring the characteristic parameters of formaldehyde/VOCs emitted from building materials

The initial emittable concentration (C0), diffusion coefficient (Dm), and material/air partition coefficient (K) are the three characteristic parameters influencing emissions of formaldehyde and volatile organic compounds (VOCs) from building materials. In existing studies, two types of C-history methods (using either sealed or ventilated chambers) have been developed to simultaneously measure these three parameters. However, they both require the emission time (t) to be longer than a specific value, which may prolong the experimental time and reduce the method accuracy. In order to overcome this limitation, we propose an improved C-history method based on the completely analytical solution of the mass transfer model describing the VOC emission process. The improved method is validated by experimental results, proving that it is reliable and convincing. Finally, optimization of experiment conditions (e.g., air exchange rate and material load) and effects of experimental errors introduced by different sources are discussed and analyzed to improve the accuracy and stability of the improved method.