Formaldehyde is a colorless gas soluble in the game can be absorbed by the respiratory tract, has been identified as suspicious by the World Health Organization and a lopsided carcinogenic substances.

• 甲醛是一种无色易溶的刺激性气体，可经呼吸道吸收，已经被世界卫生组织确定为可疑致癌和致畸形物质。