The dust or spraying material will be adhere on the water curtain positioned in front portion of the spray booth, tobe filtrate and clean up by water. Dust will also adhere on the small curtain located at the bottom, then being mixed up with tank’s water. The rest of it will be filtrated by sprinkling water at the middle of the spray booth. Hence, dust being blow out from the chimney will be fully filtrated and clean and bring no air pollution to the urrounding place.