The smoke outlet should be 3 meters higher than the tallest building within the radius of 15 meters, and the catering unit with low-altitude oil fume discharge should be 2.5 meters higher than the ground, and the oil fume discharge should be directed to the open space.

Make the cooking fume purifier directly face the lampblack emission of stairs and corridors, fully consider to avoid the influence on nearby residents, and stay away from places (such as residential buildings) and residents who are closest to air pollution and are very sensitive to air pollution. The lampblack emission should be located in well-ventilated, fully diffused and unobstructed places; ? Avoid setting oil fume outlets in patios and narrow lanes of buildings.

A closed circular sampling port should be left in the pipeline in front of the fume discharge port for sampling and monitoring by the environmental protection department. The lampblack outlet with a diameter of 15- 18cm shall not be discharged into the sewer. The oil smoke outlet and external smoke exhaust pipe are arranged neatly and beautifully, which is in harmony with the appearance of surrounding buildings.

Large and medium-sized catering enterprises that install online monitoring and concentration monitoring systems and are listed in the list of key pollutant discharge units shall install online monitoring and concentration monitoring systems for cooking fume purifiers, fume treatment and deodorization facilities. The fume treatment and deodorization facilities in small and medium-sized catering enterprises should be equipped with an online monitoring system to monitor the switch and running current of the fume treatment and deodorization equipment and fans.