How should the exhaust gas emission outlet be designed to meet the standards

　　Standardized discharge outlets are the prerequisite for scientific monitoring and evaluation of pollutant discharge. According to Article 10 of the "Law on the Prevention and Control of Air Pollution": "Facilities that discharge pollutants into the atmosphere shall, in accordance with the regulations of the environmental protection department of the State Council, declare to the local environmental protection department the pollutant discharge and treatment facilities they possess, as well as the types, quantities, and concentrations of pollutants discharged under normal operating conditions, and provide relevant technical information on the prevention and control of air pollution." It clearly stipulates that pollutant discharging units must set up discharge outlets in accordance with regulations, and failure to do so is illegal.

　　According to the provisions outlined in multiple published standard and regulatory documents, the specifications for the setting of exhaust gas emission outlets can be summarized as follows:

　　01. The exhaust gas emission outlet shall be set up in accordance with the principle of "facilitating sample collection, facilitating measurement and monitoring, and facilitating daily on-site supervision and inspection".

　　02. The exhaust funnel (chimney) should be equipped with monitoring sampling holes, sampling platforms, and safe passageways.

　　03. The sampling hole should preferably be located in the vertical pipe section and the negative pressure area of the flue.

　　04. The sampling hole should be located away from the flue elbow and areas with sharp changes in cross-section. It should be set at a distance of not less than 6 times the flue diameter downstream of the elbow, valve, and reducer, and at a distance of not less than 3 times the flue diameter upstream of the aforementioned components. For rectangular flues, the equivalent diameter D is calculated as D=2AB/(A+B), where A and B are the side lengths.

　　05. The airflow velocity of the sampling section is ≥5m/s.

　　06. Open a monitoring sampling hole at the selected measurement location. The inner diameter of the sampling hole flange should be no less than 100mm, and the length of the sampling hole pipe should preferably be between 100mm and 200mm. When not in use, it should be sealed with a flange blind plate.

　　07. The sampling platform is designed for sampling by inspection personnel and should have sufficient working area to enable safe and convenient operation by staff. The sampling platform should have an area of >6㎡, surrounded by safety fencing over 1.2m high, and the surface of the sampling platform should be approximately 0.5-1.5m away from the sampling hole.

　　08. The sampling platform should be equipped with a reliable power supply (no fewer than two 10A three-pin sockets to ensure the necessary power for monitoring equipment). A rain-proof canopy should be constructed above the platform (the canopy should cover the entire sampling platform and be equipped with lighting). The sampling platform should be easily accessible, and a safe monitoring passage should be established. When the platform is set at a height of ≥2m above the ground, an inclined ladder/Z-shaped ladder/spiral staircase leading to the platform should be constructed. The width of the staircase should be no less than 0.9m, and the angle of the ladder should be no greater than 50°.

　　09. Pollutant discharging entities are also required to carry out standardized installation of pollutant discharge outlets, which includes submitting relevant materials for declaration and installing environmental protection graphic signboards.

　　Pollutant discharging entities shall strictly adhere to the environmental impact assessment approval opinions and relevant technical specifications in setting up pollutant discharge outlets. They are prohibited from adding, moving, expanding, or altering these outlets without authorization. Failure to comply with the regulations regarding the establishment of pollutant discharge outlets will result in penalties imposed by the ecological environment department in accordance with the law.