An analysis has been conducted on important factors to decide application the models(first-order decay, double-exponential decay), which are based emission patterns from building materials. The experiment was carried out at 6 specimens for laminate flooring and wallpaper using small chamber systems. Formaldehyde was sampled and analyzed by HPLC. The results of this study were as follows. 1) For deciding important critical point to apply the model, have a direct impact on checking whether good linear relationship with predicted value and measured one or not, on section of increasing and decreasing concentration. 2) The emission patterns can be divided into three types. The first one, the typical emission pattern that emission rate distinctly increased at the beginning and then slowly decreased, is appropriate for double exponential decay. The second, the emission pattern which is minutely increased and than decreased, and it is showed the strong linear relationship on section of decreasing concentration, appropriate for first-order decay. And the third one is showed the gently increased and decreased, the strong linear relationship on both sections of decreasing and increasing concentration, is able to apply the both model.