Legal analysis: 1. Cooking and food enterprises that discharge oil fume must install oil fume purification facilities and ensure that they operate as required during operation. The unorganized emission of lampblack is regarded as exceeding the standard.

2. The length of the outlet section of the exhaust pipe should be at least 4.5 times the diameter (or equivalent diameter) of the straight pipe section.

3. The outlet direction of the exhaust pipe should be away from the easily affected buildings. The specific provisions on the height and position of the fume exhaust pipe shall be formulated by the provincial environmental protection department.

4. The smoke exhaust system should be sealed well, and it is forbidden to artificially dilute the concentration of pollutants in the exhaust pipe.

5. When the catering industry produces special odor, refer to the odor concentration index in Emission Standard of Odor Pollutants.

Legal basis: Law of the People's Republic of China on the Prevention and Control of Air Pollution

Article 2 The prevention and control of air pollution should aim at improving the quality of the atmospheric environment, adhere to source control, give priority to planning, change the mode of economic development, optimize the industrial structure and layout, and adjust the energy structure. To prevent and control air pollution, we should strengthen the comprehensive prevention and control of air pollution such as coal burning, industry, motor vehicles and ships, dust and agriculture, carry out joint prevention and control of regional air pollution, and implement coordinated control of atmospheric pollutants such as particulate matter, sulfur dioxide, nitrogen oxides, volatile organic compounds and ammonia and greenhouse gases.

Article 18 Enterprises, institutions and other producers and operators shall conduct environmental impact assessment and disclose environmental impact assessment documents in accordance with the law when building projects that have an impact on the atmospheric environment; Those who discharge pollutants into the atmosphere shall conform to the standards for the discharge of atmospheric pollutants and comply with the requirements for the control of the total discharge of key atmospheric pollutants.

Article 21 Enterprises, institutions and other producers and operators that discharge pollutants into the atmosphere shall set up air pollutant discharge outlets in accordance with laws and regulations and the provisions of the competent department of ecological environment of the State Council. It is forbidden to discharge atmospheric pollutants by evading supervision by stealing, tampering with or forging monitoring data, temporarily stopping production for the purpose of evading on-site inspection, opening emergency discharge channels in non-emergency situations, and abnormally operating air pollution prevention and control facilities.