The operation method is to place a sample with a surface area of 1 square meter in a climate chamber where the temperature, relative humidity, air flow rate, and air replacement rate are controlled at certain values. Formaldehyde is released from the sample and mixed with the air inside the box. The air inside the box is regularly extracted and passed through an absorption bottle containing distilled water. All formaldehyde in the air is dissolved in water; Measure the amount of formaldehyde in the absorption solution and the volume of extracted air, calculate the amount of formaldehyde per cubic meter of air, expressed in milligrams per cubic meter (mg/m amp; # 179;). The extraction is periodic until the formaldehyde concentration in the air inside the climate chamber reaches a stable state.