Research On Emission Characteristics Of Particulate Components From Cooking Fume

In order to research the pollution characteristics of particulates emitted from cooking fume,by conducting measurements of cooking emission from four restaurants in Shenzhen and laboratory simulated dishes?including 10 cuisines and 3 cooking methods?,mass concentration,microscopic appearance and chemical composition of particles were studied by means of online monitoring and sampling analysis.The results show that the cooking methods,oil consumption,raw materials and spices of different restaurants will affect the physical and chemical properties of cooking emission particulates.PM_2.5 discharged from restaurants at noon market accounted for 7.5%to 96.9%of the PM₁₀ concentration,indicating that the particulate matter from restaurant sources was distributed in fine and coarse particulates.The particulates from the cooking emission mainly contained six forms:flakes,lumps,clusters,flocs,globules,and irregular shapes.Among them,irregular and massive particulates account for about 30%and 21%respectively.The emission concentrations of OC from high to low was:Staff Canteen,Western Restaurant,Cantonese Cuisine,Chinese Dim Sum,which showed that high oil consumption cooking will release more OC.In cooking emission paticulates,OC is the main component,followed by EC.In addition,Cu,Fe,Zn,Ca²⁺,Cl^-,SO₄^2-account for the highest proportion of ions and metal elements.The emission factors of particulate mass concentrations followed in the order of Western Restaurant>Staff Canteen>Cantonese Cuisine>Chinese Dim Sum.It indicated that the Western Restaurant major in pan-frying and deep-frying will release more cooking emission particulates.The accuracy of particulate matter emission factors and annual emissions calculated according to meal time is higher than other calculation methods.Western Restaurants had the highest annual emissions of PM_2.5,128.17 kg/a.The baseline emission concentrations of Sichuan Restaurant and Western Restaurant was far beyond the standard and should be monitored.In the study of simulation experiment,it was found that the mass concentrations of PM_2.5released in different cooking methods ranged from large to small:stir-frying,pan-frying and deep-frying with the same amount of ingredients,spices and the same types of oils.In terms of cooking methods,the OC and OC/EC of deep-frying cooking methods had the largest values,and more metal elements and EC were released from pan-frying and deep-frying than stir-frying,which were mainly caused by the use of more oil and meat cooking.The mass concentrations of particulates released during stir-frying is the most;OC released during deep-frying is the most;metal elements and EC released during pan-frying and deep-frying are the most.In terms of cuisines,EC and water-soluble ions of Zhejiang Cuisine were the highest,OC of Northeastern Cuisine and Home Cooking was the highest,and metal elements of Northeastern Cuisine were the highest.The total composition of PM_2.5 in each cuisine were similar.The highest OC content accounted for 57.13-69.30%of the total PM_2.5,followed by inorganic ions,with the percentage content of 7.69-9.61%.Na⁺,SO₄^2-,K⁺,Cl^-and Ca²⁺had the highest concentration,and the rest were mainly metal elements?<10%?and elemental carbon?<5%?.Divergence coefficient was used to evaluate the similarity of different cooking methods,and the difference between each two cooking methods ranged from big to small:stir-frying and deep-frying?stir-frying and pan-frying?pan-frying and deep-frying.According to the calculation results of oil consumption and cooking time,the highest emission factors were Hunan Cuisine?0.59 g/L,0.35 g/h?,Sichuan Cuisine?0.44 g/L,0.26 g/h?,Shandong Cuisine?0.40 g/L,0.26 g/h?.Among them,oil consumption had a greater effect on PM_2.5 emissions from different cuisines.