Five. According to Baidu map, there are five purification board factories in Changchun, namely Jilin Jinpu Purification Board Co., Ltd., Jilin South Purification Board Co., Ltd. and Jinpu Purification Board Industry. Dust-free board, also known as clean board, is a composite board made of color-coated board, stainless steel and other materials, which has unique dustproof, antistatic and antibacterial effects.