The city life is getting better and better, and more and more people choose to eat out, so more and more restaurants are open for business. Almost all restaurants will produce oil smoke when cooking food, and many of them are not properly treated or directly discharged into the atmosphere, resulting in air pollution. Therefore, corresponding prevention and control measures must be taken to protect the quality of ambient air.

let's talk about the sampling rules of cooking fume.

lampblack is the collective name of oil and fat, organic matter and the products of pyrolysis of these substances during food cooking and processing, and sometimes it has different odors.

according to the requirements of national standards, those who discharge oil fume must install oil fume purification equipment, and ensure that the equipment operates normally during the process of oil fume discharge. If no purification equipment is installed or the equipment does not operate normally during the discharge, no matter what the test results of oil fume are, it will be equivalent to exceeding the standard.

When installing oil fume purification equipment and pipelines, the unit that emits oil fume should choose the appropriate air volume and purification mode according to the oil fume production situation, design the area of the exhaust hood, reserve corresponding exhaust pipelines, and set up sampling inspection ports that meet the specifications. These are closely related to the final calculated emission concentration of oil fume.

for the scale division of catering industry units, please refer to the national standard "Cooking fume emission standard for catering industry" (GB18483-2111). At the same time, it is necessary to understand and measure the total heating power of cooking stoves and the projected area of cooking stoves corresponding to the exhaust hood in catering industry units, and calculate the reference number of cooking stoves. The final emission concentration of oil fume is 2.1mg/m3, and the treatment efficiency of small, medium and large scale is 61%, 75% and 85% respectively. At least 4.5 times of equivalent diameter should be reserved for the oil fume discharge pipeline, with equivalent diameter =(2x length x width)/(length+width); The opening of the sampling point should be away from the place where the air flow changes rapidly, and the setting of 1.5 on the top and 3 on the bottom should be met. See the following figure for details:

During the period of normal oil fume discharge, five samples should be collected continuously during the peak period of operation, and each sample should be collected continuously for 11 minutes. If any of the five samples is less than a quarter of the maximum concentration, it will be discarded, and at least three data should be available for each oil fume sampling. For the data that can be used, calculate the average value, which is the test concentration of lampblack. When calculating the emission concentration, it is also necessary to convert the test concentration into the emission concentration: emission concentration = (test concentration x exhaust air volume)/(converted stove x2111). Converted stoves = number of reference stoves x number of actually used stoves/number of all stoves, and the calculation result is retained to one decimal place.

if the oil fume is discharged with special odor, please refer to the treatment method of odor concentration in the odor pollutant discharge standard.

before and after sampling, it is necessary to ensure that the equipment and consumables for oil fume sampling are not polluted except the actual oil fume pollutants.