In 200 1 year, the state promulgated the "emission standard of cooking fume in catering industry", which stipulated that "cooking and food enterprises that emit cooking fume must install fume purification facilities and ensure that they operate as required during operation. The unorganized emission of lampblack is regarded as exceeding the standard. However, there is no designated soot purifier merchant. 1999, the state promulgated the emission standard of cooking fume for catering industry (GWPB 5-2000) (for trial implementation), and in 200 1 year, the official national standard GB 18483-200 1 "emission standard of cooking fume for catering industry" was promulgated in China, requiring all catering enterprises.