7. Promote the integration of five aspects.

(1) Promote the integration of management mechanisms. "Integration of the two networks" is first of all the integration of management mechanisms. According to the actual situation, the functions of relevant management departments can be integrated to form a new competent department to coordinate and manage the whole industrial chain of domestic waste, such as Beijing Dacheng Management. You can also adopt the government joint meeting (or leading group) mechanism to establish a government joint meeting system (or leading group) led by the commercial administrative department and the urban management administrative department, with the participation of relevant departments, so as to promote the integration of management mechanisms and formulate plans and policy initiatives in a unified manner.

(2) Promote personnel integration. The commerce department and the urban management department fully co-ordinate and set up a system of "one post and two jobs", encouraging sanitation and cleaning workers to take part-time jobs in the classification and recycling of recyclable garbage (or recycling personnel take part-time jobs in sanitation and cleaning), and be responsible for the daily work of waste recycling, garbage sorting, ledger recording, classification and statistics in the community. Recycling enterprises shall receive waste products collected by sanitation and cleaning workers according to market conditions. The recycling behavior of sanitation and cleaning workers with one post and two posts shall be standardized according to the relevant requirements of the Ministry of Commerce for the construction of renewable resources recycling system.

(3) Promote logistics integration. According to the actual situation, all localities can promote the integration of two transportation resources, namely sanitation removal and recycling logistics, use sanitation removal vehicles to transport recyclable materials, adjust and optimize sanitation removal routes as much as possible, and share them with renewable resources logistics lines. Or adopt a market-oriented way, entrust a professional company to transport the recyclables from waste recycling trading stations, sorting points and transfer stations to the district-level renewable resources comprehensive utilization center.

(4) Promote the sharing of venues and facilities. The setting of recycling sites around the country should be connected with the classified collection points of domestic garbage or sanitation garbage houses. Where there are conditions to adjust and expand the space layout of garbage bins, garbage compression stations, transfer stations and other venues and facilities in the sanitation system, they should be adjusted and rebuilt, and recyclable recycling, sorting, primary processing stations or renewable resource transfer stations should be set up to achieve "one dual-use" and be operated by renewable resource operators, bringing sanitation and cleaning personnel into the unified management of resource recycling grassroots outlets to realize the function of superimposed recycling services. Where conditions permit, recycling enterprises and sanitation enterprises should cooperate, make unified planning of recyclable waste sorting centers, and concentrate on sorting recyclable waste, saving land and improving efficiency.

(5) Promote platform integration. Resource recovery data should be shared with sanitation classification data. Encourage the establishment of an information platform based on the Internet, the Internet of Things and cloud computing, which integrates waste intelligent classification and resource recovery, and integrates data and information collection in the whole process of source classification, resource recovery, sanitation removal, processing and utilization, and terminal processing to form big data analysis of the whole waste industry chain, providing data support for government decision-making.

8. Key points of classified delivery and classified collection

(1) Strengthen publicity and create a social atmosphere. Relevant departments and units, such as commerce, urban management, environmental protection, streets (towns), communities, real estate and operating entities, should co-ordinate and cooperate, adopt various ways and channels, strengthen the publicity of garbage classification and resource recovery, promote classified recycling into communities, schools, institutions, shopping malls and parks, raise citizens’ awareness of resource recovery and garbage classification, give play to the guiding role of public opinion, and create a good society for garbage classification and resource recovery.

(2) Source classification starts from the family. Family is the producer of domestic waste, and also the first responsible person for domestic waste classification. Therefore, the source classification of garbage should start from the family. According to the actual situation, the operator can distribute three kinds of garbage bags with different labels to the community residents (namely, kitchen waste garbage bags, recyclable garbage bags and non-recyclable garbage bags), and require residents to put the three kinds of garbage into the corresponding garbage bags at home. Harmful waste is small in quantity and low in frequency, so residents can package it separately. According to the actual situation, all localities can formulate compulsory or punitive measures for the classification of household waste.

(3) Setting of garbage collection containers. Four kinds of collection containers, including recyclable garbage, kitchen waste, non-recyclable garbage and harmful waste, are set up in residential quarters. Among them, the harmful waste collection container must have eye-catching signs, and temporary storage places should be set up in accordance with the requirements of pollution control standards for hazardous waste storage; Institutions, enterprises and institutions set up recyclable garbage, non-recyclable garbage and harmful waste three kinds of collection containers, and the unit canteen set up kitchen waste collection containers; Public, entertainment, business and other places set up recyclable garbage and non-recyclable garbage collection containers. Individuals and units put different kinds of domestic garbage into corresponding garbage collection containers respectively. Recyclable garbage, kitchen waste and non-recyclable garbage are produced daily. The amount of harmful waste is small, and the operator can determine the frequency of fixed-point collection according to the actual situation. In areas where conditions permit, we can explore canceling fixed garbage bins in residential areas, adopting the methods of regular classified delivery and classified collection, and gradually cultivate residents’ good habit of regular classified delivery of garbage.

(4) Establish incentive mechanism for classified delivery. Encourage operators to adopt intelligent waste sorting system, establish similar systems of "green account", "environmental protection file", "green bank" and point exchange through tracing the source of waste delivery and data collection, and integrate or unite commercial facilities such as community supermarkets and shopping malls to form supporting services, and provide economic incentives such as cashing points for residents’ classified delivery behavior, so as to mobilize residents’ enthusiasm for waste sorting, increase residents’ sense of honor in correct classification, and provide big data support for the government to build smart cities.

(5) Laying community waste sales sites. The setting of recycling sites should fully take care of residents’ habit of throwing garbage, that is, low-value garbage is put into garbage containers, and high-value waste is sold at recycling sites. Therefore, all localities should set up at least one waste (renewable resources) selling site in each community according to the principle of relative stability and convenience, and should be included in the overall planning of regional urban construction and management, and the district government, streets and property management companies should support it. The area of the waste sales site is 5-10 square meters, and it is set according to the construction standard of the recycling system of the Ministry of Commerce. In communities where there is no space to set up waste sales sites, operators should set up standardized mobile recycling vehicles to facilitate residents to sell high-value waste products, and streets, communities and property companies should support them.

(6) Build a "internet plus Recycling" platform. With the development of internet technology and the popularity of smart phones, it will become more and more common to sell waste products online. In addition to laying offline recycling outlets, operators should also build a "internet plus recycling" platform, establish a mobile APP terminal, and rely on the advantages of offline outlets to form an online call-in, trading, and offline quick door-to-door service acquisition system.

(7) Collect scavengers and establish a regular recycling team. Encourage operators to collect and integrate scavengers in the region, and establish a standardized and standardized recycling team with "five unifications" and "five openness" in accordance with the norms of the Ministry of Commerce for recycling system construction. Streets, communities and property companies should give strong support. For sanitation and cleaning workers with "one post and two posts", the operating entities should also carry out standardized management according to the requirements of the Ministry of Commerce for the construction of recycling teams.

(8) forming a standardized recycling network. The recycling network of operators should enter communities, enterprises, schools and institutions. A complete, advanced and standardized recycling network of renewable resources should be established through laying offline recycling outlets and building online recycling platforms, integrating sanitation and cleaning personnel and scavengers, improving the layout of renewable resources transfer stations, and cleaning up and banning illegal sites that occupy roads illegally, build illegally and do not meet the requirements of environmental sanitation.

9. Key points of classified transportation work

(1) Transportation route planning. According to the amount and distribution of garbage, all localities have scientifically planned and designed facilities and transportation lines for classified recovery, compression and transfer of domestic garbage according to local conditions, and gradually promoted the construction of large-scale multi-functional domestic garbage compression and transfer stations.

(2) Classified transportation of domestic waste. It is forbidden to transport the classified domestic garbage in a mixed way. Recyclable garbage is transported by renewable resource transport vehicles and enters the resource recycling system; The kitchen waste is transported by a special vehicle with good leakproofness and leakproofness, and enters the biological anaerobic fermentation center; Transportation in harmful waste shall comply with the relevant regulations of the environmental protection department. Encourage the integration of recycling subjects and sanitation systems, and implement the whole process of garbage classification, collection, transportation, treatment and disposal.

(3) Large garbage recycling transfer station. Conditional areas and operating entities shall set up recycling transfer stations for large-scale garbage for centralized, temporary storage and sorting.

10, classification processing work points

(1) classified processing. Recyclable garbage is processed and utilized by renewable resource enterprises; The kitchen waste is processed and utilized by the biological anaerobic center; The kitchen waste shall be treated biochemically by the service unit that has obtained the business license for the disposal of kitchen waste; Non-recyclable garbage is used for energy utilization by means of incineration power generation and sanitary landfill, so as to minimize the amount of primary garbage landfill; Harmful waste should deliver enterprises with hazardous waste disposal qualification and hazardous waste business license for harmless disposal.

(2) Renewable resource sorting center. Each district (or small city, county) should build at least one sorting center for renewable resources, and allocate necessary facilities and equipment according to the requirements of urban management, environmental protection and fire safety, so as to meet the requirements of weighing, sorting, sorting, sorting, dismantling, packaging, temporary storage and primary processing after centralized recycling of renewable resources. Recyclable garbage sorted by various communities is concentrated in the sorting center for sorting, sorting, packaging and primary processing, which is convenient for docking with the comprehensive utilization chain.

(3) Layout low-value recyclables processing and utilization chain. Encourage operators to obtain the support of local government according to local resources and their own conditions, adopt PPP method to lay out the processing and utilization chain of low-value recyclable garbage, and establish resource processing and utilization centers such as waste glass, waste textiles, waste plastic bags, waste soft packaging, waste furniture and kitchen waste to ensure that the resources classified at the front end have a place to go and can be used.

(4) Establish a comprehensive utilization base for cooperative treatment of domestic waste. Encourage qualified operators, obtain the support of local government, explore the establishment of a comprehensive utilization system for domestic waste collaborative treatment, make overall planning and construction of a comprehensive base for collaborative treatment of waste incineration, sanitary landfill, kitchen waste resource utilization, renewable resource processing and utilization, and harmful waste harmless disposal, implement the co-construction and sharing of infrastructure such as fire protection, safety and environmental protection in the base, and allocate relevant facilities in a clean, intensive, integrated and efficient manner to realize waste treatment, resource utilization and hazardous waste disposal.

11, vigorously explore the support measures.

(1) Establish a policy guarantee mechanism for low-value garbage. It is necessary to explore financial support policies for low-value recyclables, subsidize low-value recyclables with special funds, and form a long-term operation mechanism for low-value garbage recycling. According to the actual situation, all localities should calculate the special subsidy standard, which can be reversed according to the garbage disposal fee and clearing freight, or calculated according to the recycling, storage, transportation and treatment cost of low-value garbage.

(2) Explore the extended producer responsibility system. It is necessary to study and explore the introduction of extended producer responsibility system for different kinds of low-value recyclables, so as to promote the recycling of low-value garbage such as express packages and tetra pak. At the same time, where conditions permit, we can explore the charging system for domestic garbage, and whoever produces garbage will pay for it.

(3) Construction of relevant laws, regulations and standards. All localities should speed up the exploration of the legal requirements for compulsory garbage classification, establish a relevant standard system for domestic garbage classification, refine garbage categories, and clearly identify signs. Conditional cities will first introduce laws and regulations on compulsory classification of local domestic waste, formulate incentives and penalties for compulsory classification, and issue a catalogue for guiding the classification of domestic waste.

(4) Explore the ways of government purchasing services. All localities should vigorously explore the mode of government purchasing services (PPP mode), incite market forces, and guide all sectors of society to carry out classified recycling of domestic waste. Guangzhou’s experience has proved that PPP mode is a feasible mode to mobilize market forces to participate in the reduction and recycling of domestic waste.

　　Tired of takeout?

　　Today, Xiaobian gives you a change of taste!

　　Tofu that can be "drunk"? Cooking food with tea leaves? And the dish is called farewell my concubine?

　　Special cuisine of cities along the canal

　　Here we come ~

　　01 Beijing

　　Roast duck — — It is a famous Beijing dish with world reputation, which originated in the Southern and Northern Dynasties in China and belongs to court food.

　　Although it is shiny and shiny, the high-quality duck meat, after being roasted with fruit, wood and charcoal fire, presents a mellow, fat but not greasy appearance for diners, and is known as "delicious in the world".

　　02 Tianjin

　　Guifaxiang 18th Street Twist — — Tianjin’s century-old dough twist shop, together with Tianjin Goubuli steamed stuffed bun and Erduoyan fried cake, is also called "Tianjin Three Musts". As the name implies, its shop was once located at 18th Street, Dagu South Road, so its name is "Guifaxiang 18th Street Twist", but people are more accustomed to calling it 18th Street Twist.

　　Guifaxiang 18th Street Twist was recognized as "Chinese Famous Snack" at the first national famous snack recognition meeting, and was named "Chinese Time-honored Brand" by the Ministry of Internal Trade of China in 1996.

　　In the center of Guifaxiang’s twist, there is a mixed stuffing crisp bar made of sesame, peach kernel, melon seed, green plum, osmanthus fragrans, green shredded pork and essence water. After deep-frying, it will also be accompanied by small materials such as rock candy, green red silk and melon strips on its surface. Layers of attack, showing a crisp and sweet taste.

　　03 Cangzhou

　　Hotpot chicken — — Originated in Cangzhou, Hebei Province, it is a well-known, very popular and affordable food in Cangzhou. When eating, you can also rinse with other dishes according to your own preferences, with accessories such as aged vinegar and garlic paste, which is rich in flavor and memorable.

　　Spicy and delicious hotpot chicken with unique taste is an excellent side dish for next meal!

　　04 Dezhou

　　Braised chicken — — The first of the four famous chickens in China. Dezhou braised chicken production skills are listed as national intangible cultural heritage. In terms of its age, it has a history of more than 300 years! As early as the Qianlong period of the Qing Dynasty, Dezhou braised chicken was listed as a Shandong tribute and sent to the palace for the emperor and the royal family to enjoy!

　　Dezhou braised chicken is famous all over the country because of its unique production method, rotten and boneless meat, delicious color, fat but not greasy taste, and is known as "the best chicken in the world"

　　05 Linqing

　　Tofu with pallets — — Because the seller always cuts it and sells it on a special rectangular board, it is called "pallet tofu". Especially in the morning of Linqing, customers holding pallet tofu for breakfast can be seen everywhere in the streets and lanes, which is not only nutritious, but also delicate, mellow and fragrant!

　　After reading the pictures, are you thinking, "Isn’t this just an ordinary piece of tofu? Where can’t I eat it?" All wet!

　　Tofu with a pallet is made of superior soybeans, which are peeled and soaked, ground into juice, filtered out with cloth, boiled in a pot, and carefully ordered with brine. The most important thing is that it should be "drunk" and eaten. Its tenderness basically does not require chewing. It is a traditional food suitable for all ages.

　　Friends who love tofu must not miss trying this unique way of eating, sweet and delicious plate tofu!

　　06 Yangzhou

　　Lion head — — A traditional dish in Huaiyang Cuisine in Yangzhou, Jiangsu, China Province. Legend has it that the lion’s head practice began in the Sui Dynasty. When Emperor Yangdi was on a lucky trip, the chef made four dishes, including sunflower chop meat and sunflower meatballs, with the theme of four famous scenic spots in Yangzhou.

　　The meat of lion’s head is fresh and tender, fragrant and mellow, crisp and delicious, suitable for all seasons. Some Song people praised its delicious taste with the poem "But one cup is matched with two crabs, and there are really Yangzhou cranes in the world".

　　07 Suzhou

　　Shrimp with snails — — Suzhou, Jiangsu, a traditional famous dish, as its name implies, mainly uses shrimp as the main ingredient and skillfully uses Biluochun as the ingredient. Using the fragrant tea juice of New Biluochun as seasoning, it is cooked with shrimps. The delicious taste of shrimps and the fragrance of famous tea complement each other.

　　Shrimp is as white as jade, and tea leaves are decorated in it. The entrance has a fresh tea fragrance, fresh and tender teeth, and a little sweetness. This combination is bold and delicious, which makes people "love it"!

　　08 Hangzhou

　　West Lake Vinegar Fish — — Also called Uncle and Sister-in-law Chuan Zhen, Song Saoyu. On September 10, 2018, "Chinese food" was officially released, and "West Lake vinegar fish" was rated as one of the top ten classic dishes in Zhejiang.

　　West Lake vinegar fish usually uses grass carp as raw material and is cooked. The surface is covered with a layer of smooth and oily sweet and sour, and the fish is tender and beautiful. If you taste it carefully, there will be a crab-flavored surprise, which is sweet and sour and intriguing.

　　09 Xuzhou

　　Farewell my concubine — — This dish was created by the people in Xuzhou area to commemorate Xiang Yu, a hero of Chu who made great contributions to overthrowing the rule of Qin Dynasty, and to miss Yu Ji, a peerless beauty who was deeply concerned about the country and was righteous and upright, and has been passed down to this day.

　　At present, soft-shelled turtle and chicken are the main ingredients, and the soup is clear, fresh and mellow. The meat of chicken and soft-shelled turtle is tender, crisp and rotten, and rich in nutrition, which is the best in the banquet.

　　Its nutritional value can be imagined, and it is one of the good choices for people who need dietotherapy, such as malnutrition, chills, fatigue, irregular menstruation and anemia. But it doesn’t mean it is suitable for everyone. Please call a professional doctor for the specific operation ~

　　Well, that’s all for today’s "food report". Bring your eager stomach and feel the food culture of the Grand Canal!

Recently, heavy rain has hit many provinces and cities in southern China. I believe what you hear most in the report is "affected by El Ni? o", but do you know how El Ni? o affects the weather? How should we deal with the rainstorm to ensure our own safety to the maximum extent? In this issue, follow Xiaobian to learn science to answer your questions!

With the south wind blowing continuously from the South China Sea to the mainland, it marks the beginning of the rainy season in China. From the end of March this year, South China entered the first flood season, nearly 16 days earlier than before. According to the news of China Meteorological Bureau, there have been 17 times of heavy precipitation in the south since the flood season. The monitoring shows that the precipitation in southern China is obviously higher than that in previous years. The precipitation in the whole southern region is generally higher by 25%-100%, and even reaches 100%-200% in some areas.

Figure 1 Precipitation in eastern China in April compared with the same period of previous years (percentage)

Taking Guangzhou as an example, the cumulative precipitation in Guangzhou from March 6, 2016 to June 1 has been nearly 300 mm more than in previous years, and nearly 50% more than in normal years. As can be seen from the figure, there was a sudden increase in precipitation at the end of March (between March 16 and March 21), because South China, where Guangzhou is located, entered the pre-flood season, and the precipitation in Guangzhou was obviously higher after the start of the pre-flood season.

Fig. 2 precipitation in Guangzhou compared with normal years

The so-called pre-flood season in South China refers to the rainy period in South China, which starts from the end of March and early April and ends around June. It usually marks the beginning of the summer rainy season in the whole China monsoon region. During this period, cold and warm air meet in opposition, and besides rainstorm, there are often strong convective weather phenomena such as thunderstorm, gale and hail.

What needs to be known is that the most important weather system affecting China is the western Pacific subtropical high, which is referred to as "western Pacific subtropical high" for short or directly called "subtropical high". The west side of the subtropical high will guide the water vapor northward, while the northern boundary of the subtropical high is often connected with the cold air southward, so the position of the subtropical high often determines the position of the rain belt. The movement time and advance and retreat speed of subtropical high determine the movement time and advance and retreat speed of rain belt.

During the first flood season in South China, the northern boundary of the subtropical high is located in the coastal area of South China. The subtropical high and the southwest jet in the westerly trough of the south branch jointly transport warm and humid air over South China. Before the cold air goes south, the warm and humid air accumulates in South China, which makes the air humidity gradually increase and the air gradually reach saturation, forming dew on the ground and walls. This is the "returning to the south sky" in South China.

The intersection of cold and warm air masses is called "front", and when the "front" lingers and moves less, it is called "quasi-static". When the cold air in the north continues to go south, it conflicts fiercely with the warm and humid airflow, forming a quasi-static front, which is called "the quasi-static front in South China".

At this time, because the subtropical high can’t go northward immediately because of the blocking of cold air, it stagnates in South China, and there will be a continuous precipitation weather process in South China, which is the first flood season in South China.

In the first flood season in South China, due to the frequent cold air activities and the water vapor can’t completely go north, the precipitation in North China is often less, and high temperature and dry weather often occur. This is the spring drought in North China. During this period, the weather situation of flooding in the south and drought in the north often occurs in China.

In late June, the southern part of China is usually in summer, and the subtropical high gradually becomes stronger, and the subtropical high will gradually move northward and stagnate in the middle and lower reaches of the Yangtze River. The quasi-static front on the ground will gradually move northward to the Jianghuai area, forming the so-called quasi-static front in Jianghuai. During this period, there will be a continuous precipitation weather process in the middle and lower reaches of the Yangtze River, which is the prestigious Jianghuai Meiyu, and the quasi-static front of Jianghuai is also called "Meiyu Front".

In fact, in addition to China, the continuous precipitation weather processes in the same period in South Korea and Japan are also called Meiyu, and they are called Meiyu together with Jianghuai Meiyu. Internationally, Meiyu sometimes directly refers to the summer and rainy season precipitation in East Asia, and that quasi-static front is directly called Meiyu front.

However, in some years, when it is in the pre-flood season in South China, the subtropical high will sometimes suddenly move northward to the Yangtze River basin, and the rain belt will also move northward to the Yangtze River basin, and the precipitation in South China will have a stagnant period. However, there will be a weather process similar to plum rain in the Jianghuai basin, which is called "early plum rain". For example, in late May of this year (2016), the Yangtze River Basin experienced an early rainy weather process. At that time, the Yangtze River Basin did not enter summer, but there was a continuous rainy weather process similar to Meiyu, which was actually the reason why the subtropical high suddenly moved northward. The biggest difference between early Meiyu and Meiyu is that after the early Meiyu, the subtropical high will retreat to South China again, and the rainy area will return to South China again; After the Meiyu process, the subtropical high will continue to move northward to North China, forming a rainy season in North China.

After the Meiyu, the subtropical high moved north and North China entered the rainy season. At this time, South China will be re-controlled by the tropical system going northward with the subtropical high, and there will be a wave of precipitation concentration period, which is called the late flood season in South China. During this period, North China and South China entered the flood season, while the Yangtze River basin was located in the subtropical high, and entered the summer drought period, so the precipitation situation in the whole country easily became a "waterlogging-drought-waterlogging" model.

Since last year, the public has generally heard the news of El Ni? o, and El Ni? o has also made 2015 the hottest year since the temperature record was recorded in 1880. The appearance of El Nino will make the sea water temperature in the eastern Pacific rise. However, due to the weakening of the easterly wind, it is difficult for the warm sea water in the eastern Pacific to spread westward to the northwest Pacific, while the sea water in the northwest Pacific will be relatively cold, which will lead to the weakening of convection and the weakening of the western Pacific subtropical high, which usually occurs in the year after El Ni? o. According to this El Ni? o, the next year of El Ni? o is 2016. The weakening of the subtropical high will lead to the lack of motivation to go north, which means that the time of staying in the south will become longer, and the time of continuous precipitation in the southern basin may also become longer, which is prone to flood disasters.

For example, 1998 was also the year after El Nino. At that time, there was a big flood in the Yangtze River basin, and the people in the Yangtze River basin experienced a difficult period of fighting floods. The intensity of El Nino this time was the same as or slightly weaker than that in 1998. With the continuous improvement and development of national flood control facilities, the people have a strong flood protection. Although it may not be the same as in 1998, it is also necessary to learn from history. In order to prevent the historical disaster from repeating itself, we need to be vigilant.

When heavy precipitation weather occurs, stay away from low-lying areas. People in mountainous areas need to guard against geological disasters such as landslides, do not wade reluctantly, stay away from rivers, embankments and other areas, and go to safe areas in time when danger is found. Similarly, it is also necessary to pay close attention to the official information released by meteorological departments and flood control departments, take a responsible attitude towards the safety of their own lives and property, cooperate with the disaster prevention measures of government departments, and follow the instructions to evacuate in time when they are in dangerous areas.

Note: In this paper, the precipitation anomaly map in the eastern region is drawn by the National Atmospheric and Oceanic Administration (NOAA), and the precipitation in Guangzhou region is drawn by the National Climate Prediction Center (CPC). Meteorological data required for mapping are provided by the observation stations participating in the global exchange of the World Meteorological Organization (WMO).

The article was produced by China, a popular science student, and was authorized to be published in the column "Learning Science with Xiaobian" of CCTV. Please indicate the source for reprinting.

Production: Mobei

Producer: computer network information center

　　In recent years, it has been found that fluorescent brighteners are very harmful to human health, and cosmetics containing fluorescent brighteners have attracted widespread attention for a time. So, is fluorescent whitening agent really that terrible?

　　What is a fluorescent whitening agent?

　　Let’s get to know the fluorescent whitening agent first. It is a kind of fluorescent dye, which belongs to a separate category in the Colour Index (C.I．). The molecular structure of fluorescent whitening agent is mainly composed of a continuous conjugated system containing aromatic rings and one or more substituents. The special chemical structure enables it to absorb ultraviolet rays invisible to the naked eye, and then stimulate visible fluorescence (usually blue or blue-purple), which can make up for the lack of blue light in the reflected light of yellowish white objects, enhance the reflected light in the blue band, improve the whiteness and brightness of white objects to the naked eye, and make the brightness of colored objects brighter and more pleasing. This characteristic of fluorescent whitening agent has made it develop rapidly in the fields of textiles, paper, washing products, plastics and so on, and is considered as one of the three great achievements in the dye industry in the late 20th century.

　　At present, there are more than 15 structural types of fluorescent brighteners produced all over the world, and more than 1000 commercial fluorescent brighteners are available. According to different structures, fluorescent brighteners can be divided into stilbene type, benzoxazole type, pyrazoline type, coumarin type, naphthalimide type and other types. Among them, stilbene fluorescent whitening agent is the fastest growing branch.

　　The safety of fluorescent whitening agent is closely related to its structure, so it cannot be generalized. Different industrial fields have clear requirements for the use of fluorescent brighteners, so consumers don’t have to think that fluorescent brighteners are unsafe as soon as they hear them. For example, the "Fluorescent Brightener for Detergents" (QB/T2953-2008) stipulates that stilbene biphenyl and bis-triazine amino stilbene fluorescent brighteners can be added in the production of various detergents for clothing.

　　As early as 1999, CEFIC and European Detergent Association (A.I.S.E) started the project "Human and Environmental Risk Assessment of Household Cleaning Products in Europe" (HERA), and completed the safety assessment and risk assessment of stilbene fluorescent brighteners commonly used in laundry detergents, such as fluorescent brightener 71. The conclusion is that it will not cause adverse effects on human body and environment.

　　China’s food industry stipulates that it is strictly forbidden to artificially add fluorescent whitening agents in the processing of food and related products. However, because some natural plant materials such as bamboo contain fluorescent substances themselves, it may be inevitable to bring trace fluorescent substances into packaging materials, but their residues should be strictly controlled.

　　What kind of cosmetics are easy to contain fluorescent whitening agents?

　　Affected by the safety problems of fluorescent whitening agents in cosmetics reported by some media in recent years, more and more consumers began to pay attention to this problem. According to incomplete statistics, fluorescent whitening agents that can be found in EU cosmetic raw material database include fluorescent whitening agent 184, fluorescent whitening agent 230, fluorescent whitening agent 236, fluorescent whitening agent 264, fluorescent whitening agent 351, fluorescent whitening agent 367 and fluorescent whitening agent 393, which indicates that these raw materials may have been applied to cosmetics. Among them, fluorescent whitening agent 351 has been included in China’s Catalogue of Used Cosmetic Raw Materials (2015 edition).

　　Fluorescent brighteners may be used in cream, cream, emulsion, nail polish, facial mask and other products, which makes the appearance of cosmetics after adding more white and crystal clear. Because optical brighteners are mainly used to improve the appearance of products, their use in cosmetics is neither necessary nor common, and the dosage will not be too large. Some media reported that the problem of detecting fluorescent whitening agent in cosmetics focused on mask products. The main reason is that fluorescent whitening agents are added to mask carriers such as non-woven fabrics, or the carriers made of natural plant fibers contain fluorescent substances. China’s "Technical Specification for Cosmetic Safety" (2015 edition) stipulates that packaging materials that come into direct contact with cosmetics should be safe, and must not react with cosmetics, and must not migrate or release toxic and harmful substances that are harmful to human body.

　　So, is the mask used in the carrier or containing fluorescent whitening agent safe? This requires a scientific safety assessment based on product characteristics. Specific to the mask, the factors to be considered include whether the carrier is safe or not; Whether the fluorescent whitening agent will migrate from the carrier and attach to the skin surface during the use of the mask; How much will remain on the skin according to the way of use, whether it will be absorbed by the skin, and whether it will accumulate in the human body after absorption.

　　According to the existing knowledge, there are few reports on the migration of fluorescent whitening agent, and we can’t know whether the fluorescent whitening agent will migrate from the mask carrier, but it is difficult for the fluorescent whitening agent to be absorbed through the skin (unless there is a wound on the skin and the normal barrier function is destroyed), so even a small amount of migration will have little impact on human health. Scientific experiments show that if there is a wound on the skin, the fluorescent whitening agent will combine with protein in the human body through the wound, which will hinder the wound healing. Therefore, it is not recommended to use cosmetics that may contain fluorescent whitening agents when the skin is damaged.

　　How to detect fluorescent brighteners in cosmetics

　　When it comes to the detection of fluorescent brighteners, the first thing that people think of is to use a money detector to illuminate, which is the ultraviolet lamp method. Because the principle of fluorescent whitening agent is that the blue light excited by ultraviolet light neutralizes the yellow light, it can be judged whether the object emits blue fluorescence by direct irradiation with ultraviolet light. This method is very simple and can be used by ordinary consumers, but it also has certain limitations. Because this method can only tell you that the product has "fluorescence" phenomenon, it can’t prove that fluorescent whitening agent is definitely added, and it can’t prove what is added and what is the content. Of course, it is helpful for ordinary consumers to avoid buying products containing fluorescent substances.

　　The second method is ultraviolet spectrophotometry, which requires professional instruments and equipment. By measuring the amount of light absorbed by different fluorescent whitening agents, the content is determined by comparing with the standard. This method can accurately determine the content of fluorescent whitening agent, provided that we know what fluorescent whitening agent is used. The equipment used in this method is cheap and easy to operate, and it can be used for product detection in enterprises. However, the cosmetic matrix is very complex and easy to interfere, so it is risky to detect unknown products and should not be popularized.

　　The third method is molecular fluorescence spectrophotometry, which determines the type and content of fluorescent whitening agent according to the reflected light intensity and wavelength. However, the fluorescent whitening agent needs to be separated from the product before the determination, so it is not suitable for cosmetics with complex matrix as the second method, and is more suitable for determining the type of fluorescent whitening agent used in raw materials.

　　The fourth method is high performance liquid chromatography (HPLC), which separates the pre-treated samples by chromatography, detects them with a suitable detector, and accurately quantifies them according to the corresponding fluorescent whitening agent standard. The detection cost of this method is high, and it is suitable for accurate quantification of specific fluorescent brighteners in complex matrix in professional inspection institutions. However, if conventional ultraviolet or fluorescence detectors are used, it will have certain limitations to determine unknown fluorescent brighteners. If mass spectrometry detector is used, the separation, qualitative analysis and quantitative analysis of fluorescent whitening agent can be realized at the same time, and the instrument has high sensitivity, which is very suitable for qualitative confirmation and quantitative analysis of unknown fluorescent whitening agent in complex matrix.

　　To sum up, the probability of containing fluorescent whitening agent in cosmetics is extremely low, and even the products containing fluorescent whitening agent are not necessarily unsafe, and they are all safe under normal dosage, so consumers should keep a good attitude.

　　(Author: Zhu Ying, Institute of Environmental and Health-related Product Safety, China Center for Disease Control and Prevention)