Cooking kitchen soot particles in residential kitchens is a major source of indoor air pollution and an unresolved problem in the indoor air quality of residential buildings. Some researchers at home and abroad have carried out research on the control of soot particle pollution in kitchen space from different angles. Chiang et al1 used computational fluid dynamics to study the effect of the geometric design of the kitchen exhaust hood on the spread of soot pollution. Yang Hongbo et al.2 analyzed the main influence of kitchen exhaust hood on soot control through experimental research. Hu Jianjun 0 used the numerical method to study the control of the fume of the exhaust hood jet air curtain. Zhu Peigen et al. H pointed out that increasing the amount of exhaust air has a bottleneck in improving smoke exhaustion. Based on the experimental study of the smoke exposure process in the human respiratory zone, this paper intends to explain the influence of kitchen ventilation conditions on the exposure value of different particle size soot particles. From the analysis of the existing conventional range hood exhaust + door and window ventilation mode, the smoke in the breathing zone is abnormally high. The concentration angle reveals a misunderstanding of the current kitchen fume particle pollution control, that is, relying solely on the efficiency of the hood or the unorganized natural air intake of the kitchen. 1The experimental system and test method is the residential kitchen fume exposure research laboratory kitchen (3.5mX1.8mX2.4m) built in a large laboratory space, there is the National Natural Science Foundation of China (No.50908163); Shanghai Youth Science and Technology Qixing Project (No.11QA1406800); State Key Laboratory of Pollution Control and Resource Reuse Research (No.PCRRF09009) Gao Jun (1977-), male, Ph.D., associate professor, a south-facing exterior window facing the large space laboratory, and Opposite the exterior window, it is basically similar to the actual ventilation of the residential kitchen. The experimental system includes: a high-low speed two-speed air hood, one induction cooker, one heating pot; a new air supply system (for the next research work). The test instruments used in the experiment mainly include: LD-)S multi-function laser dust meter, which can monitor 4 different particle size particles, the sampling flow rate is 2.0L/min, and the recorded value is accurate to 0. 001mg/m3; QDF-3 Type hot wire anemometer, there are two measurement files, respectively. ~ ~30m / S; temperature measuring instruments, respectively, copper-constantan thermocouple (measuring the ambient temperature in the kitchen), Pt100 thermal resistance (measuring oil temperature) and FlukeHydra portable data collector. The experimental oil is edible soybean oil. Experimental procedure: Before heating the oil, first measure the background concentration of the particles in the kitchen; then turn on the induction cooker to monitor the concentration of the soot particles, interval 30s, test time 30min; open the doors and windows, adjust the range hood to high speed, quickly reduce the kitchen soot particles Concentration, the background concentration was measured again; the next set of experimental conditions was performed. The ventilation conditions of the kitchen are set as follows: A. Close the window, close the door, open the range hood, and close the working condition (the winter kitchen is mainly operated under this ventilation condition, the ventilation condition is the most unfavorable); B. Close the window, open the door, open the pumping The average monitoring temperature of the oil temperature is 0.613mg/the opening condition of the hood; C. opening the window, opening the door, opening the range hood with a double opening condition (most of the summer residents' kitchens are running under this ventilating condition); D. opening the window, Close the door, open the range hood and open the window. According to the above four ventilation conditions and the air volume of the range hood, a total of 8 experimental conditions were generated (see Table 1). After testing, the wind and air of the range hood are 518.4m3/h and 476.8m3/h, respectively. Under the open condition, the corresponding air volume is 563. Due to the diversity and complexity of the cooking process, the soot particle concentration The test stability is difficult to control, and the method of static edible oil heating is used to achieve a relatively stable soot emission process. The oil temperature heating process adopts the temperature control method, and each working condition is heated from the initial ambient temperature to about 220 ° C (for example). Table 1 Schematic diagram of experimental conditions, closed working conditions (A) High-speed gear, low-speed gear opening condition (B) High-speed gear, low-speed gear, double-opening condition (C) High-speed gear, low-speed gear, window opening condition (D) High-speed gear, low-speed gear, 2 experiment Results and Analysis 2.1 The closed working condition (A) is the change of the mass concentration of the soot particles in the case of door and window closing, which is consistent with the trend of the temperature change curve, indicating that the soot emission is enhanced with the increase of temperature. The results also showed that there was no significant difference in the concentration of soot particles in the breathing zone when the range hood was working at high and low levels, indicating that the increase in the air volume of the range hood could not significantly reduce the concentration of soot particles in the breathing zone within the range of the exhaust air volume. Under the A1 condition, the average monitoring mass concentrations of PMw, PM5, PM25, PM and soot particles are 8.276mg/m3 and 6.278mg/m3, respectively, which is much larger than the indoor inhalable particulate matter (PM10) specified by the indoor air quality standard S. The average maximum allowable concentration is 0.15mg/m3, and the daily average concentration limit of PMi5 specified in the Environmental Air Quality Standards Draft is 0 075mg/m3. There is no basis for the short-term exposure limit of soot particles, but 30min of PM10 and PM2.5. The average exposure concentration is 54.2 times and 58.9 times higher than the standard 24h average exposure limit, which still reflects the extremely high exposure concentration of the smoke zone in the breathing zone. Under the A2 working conditions, the sweat dish 1., the dish 5, the dish 2.5, the dish 1. The average supervision 2.2 opening condition (B) is the change of the mass concentration of the soot particles when the door is closed. Compared with the above closed working condition (A), the concentration of soot particles in the breathing zone is greatly reduced, and the increase in the air volume of the range hood significantly reduces the exposure concentration in the respiratory zone, but the concentration value is still more than doubled compared with the relevant standard. Under the B1 working condition, the average monitoring concentrations of PMi, PM5, PM2.5 and PMi.0 were respectively 0.136mg/m3, of which PMW and PM2.5 were 2.0 times and 1.6 times higher than the daily average exposure limit of 24h; B2 working condition 01å€å€å€å€ã€‚ The PMw, PM5. PM2.5 respectively higher than 24h daily exposure limit 3.1 times and 1.8 times. 2.3 Double-opening condition (C) is the change of the mass concentration of soot particles under the condition of opening the door and opening the window. It can be seen from the figure that the mass concentration of the soot particles fluctuates greatly, the fluctuation of the C2 working condition is more severe than that of the C1 working condition, and the average concentration exceeds the standard much larger than the working condition B. The test found that the wind speed outside the window in the C1 working condition fluctuated in the range of 0.15~0.7m/s, and fluctuated in the range of 0.3~1.2m/S in the C2 working condition; the unorganized air in the natural fluctuation of the outdoor wind speed was in the fixed degree. The plume emitted by the soot is destroyed, affecting the main body movement trajectory of the soot particles, and the concentration value of the breathing zone is generated from time to time, and the exposure concentration is larger than the working condition B. Under the condition of C1, the measured concentrations were 1. respectively higher than the daily average exposure limit of 14.4 times and 7.8 times; under the condition of C2, the average monitoring concentrations of PMW, PM5, PM2.5 and PM1.0 were 4.024 mg/m3 respectively. 2. The dish 1., the dish 2.5 is higher than the 24 匕 daily exposure limit of 25.8 times and the 2.4 windowing condition (D) is the change of the mass concentration of the soot particles only when the window is opened and the door is closed. It can be seen from the figure that the particle concentration fluctuation under this condition is more severe than the above-mentioned working condition C, and the exposure concentration value in the respiratory region is higher. Under the D1 condition, the average daily exposure was 342mg/m3 and 2.043mg/m3, respectively, and PM10 and coffin 2.5 were respectively higher than the 24-day average exposure limit of 27.2 and 30.2 times. 3 The conclusion exceeds the standard multiples according to the working conditions are A>D>C>B, the highest exceeds the standard 58.9 times, the lowest exceeds the standard 1.6 times. When the A working condition doors and windows are closed, the soot particle concentration exceeds the standard is the most serious, and the D working condition outer window is opened. The door is closed secondly, the C working condition doors and windows are double opened again, the B working condition door is opened, and the window closing exceeds the minimum. The statistics of the experimental results also show that the average percentage of PM25 in the soot is 47%, and the mass of PM2.5 fine particles in the soot particles is very harmful to human health. The organization and effectiveness of supplemental wind is the key to improving exposure to smoke in the respiratory zone and should be the focus of the next step. Yang Hongbo, Zhao Yonghua, Wang Hanqing. Experimental study on the suction-type range hood device Hu Jianjun. Research on optimization control of air quality in residential building kitchens. Hengyang: Nanhua University, 2006. Zhu Peigen, Zhu Mingliang, Cai Hao, Luo Qing. Numerical simulation and actual measurement of soot concentration in residential kitchens. Journal of PLA University of Science and Technology (Natural Science Edition), 2006, GB/T18883~2002 indoor air quality standards. Beijing: China Environmental Science Press, 2003. 75 Inch Teaching Interactive Whiteboard The use of high-efficiency multimedia 75 inch Teaching Interactive Whiteboard in education will not only improve the teaching efficiency of the school, but also improve the teacher's ability to guide students correctly, and 75 inch teaching smart whiteboard can let teacher spend time in effective places instead of wasting ineffective things. The intelligent touch 75 inch teaching all-in-one machine gives teachers more room for expression. 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