Will there be formaldehyde when Hengdian brown mat sleeps for 20 years?

The volatilization cycle of formaldehyde is long, ranging from three to fifteen years.

Formaldehyde, with chemical formula of HCHO or CH_O and molecular formula of 30.03, is also called Formaldehyde. Colorless gas, irritating smell, irritating to people's eyes, nose, etc. The relative density of gas is 1.067 (air = 1), and that of liquid is 0.8 15g/cm_(-20℃). Melting point -92℃-19.5℃. Soluble in water and ethanol. The concentration of aqueous solution can reach up to 55%, usually 40%. It is called formaldehyde water, commonly known as formalin, which is a colorless liquid with an irritating smell. Soluble in water and ether, the highest concentration of aqueous solution can reach 55%.