Keywords: 
• formaldehyde /
• re-release /
• nonlinear fitting /
• first order exponential function

Abstract: Environmental test chamber is widely used to determinate the pollutant emission value of wood-based panels and testing the purificatory effect of indoor environment decontamination product. But the particles adhered to the wall of the test chamber also adsorbe formaldehyde from the formaldehyde emission source and form re-releaseing source of formaldehyde and affect the subsequent testing. So it is necessary to investigate the re-releasing rules and its influencing factors in order to improve the subsequent testing and proposed guidance opinion on the control of indoor pollution. In this project， 0.2% formaldehyde solution and the wood-based panels was selected as formaldehyde emission source in the glassing test chamber for the two group experiments respectively. Trough 90 days experiment under the condition of different formaldehyde emission source and different controlling methods， a lot of experimental data were obtained. The experimental data were processed with integrate nonlinear fitting， and it was found that the re-releasing value of formaldehyde concentration of self-adsorbed formaldehyde in the chamber was changed accord with a first order increment exponential function: y=A1×exp(-x/t1)+y0，（A1＜0、t1＞0）. The y0 value can be used to evaluate the residue value of formaldehyde in the chamber. It also can be found that the y0 value is connection with the material of the chamber， the temperature， the relative humidity， and the means of the air ventilation. But it is independent to the release source of formaldehyde and the releasing steady-state concentration of formaldehyde. Opening the chamber door and extracting air ventilation in a short time will benefit reduction of the residual formaldehyde in the chamber. But it is no visible effects to reduction of the residual formaldehyde in the chamber with unpowered air ventilation， furthermore it also can be found that is useless to reducte the residual formaldehyde washed with deionized water.