1.What should the public do in the event of a nuclear and radiation emergency? In the event of a nuclear and radiation emergency, the first thing the public must do is to obtain as much credible information as possible about the emergency and learn about the decisions and notifications of government departments. They should maintain communication with local authorities by all means, and remember not to believe rumors or gossip. The second thing is to quickly take the necessary protective measures to protect yourself. For example, you can choose the nearest building for concealment, and you should close the doors and windows and turn off the ventilation equipment. Implement an organized and orderly evacuation according to the arrangements of the local government. When a radioactive dispersal event is judged to have occurred, it is important not to run into the wind or with the wind, but to try to hide to the side of the wind and to quickly enter the building for shelter. Take respiratory protection, including covering the mouth and nose with wet towels, cloth blocks, etc. to filter radioactive particles. If radioactive contamination is suspected on the surface of the body, use bathing and changing clothes to reduce radioactive contamination. Prevent ingestion of contaminated food or water. In the event of a nuclear and radiation terrorism event, the public should pay special attention to keep their minds calm and should never be frightened. 2.What public protection measures can be taken to reduce these radiations? The main protective measures to prevent or reduce external exposure are to evacuate nearby populations and cover populations in more distant areas. Ingestion of radioactive iodine can affect the thyroid gland, especially for people aged 0-18 years. Therefore, to prevent internal exposure hazards from radioactive iodine, stable iodine (KI) should be taken according to the relevant standards in the national emergency plan. In case of radioactive fallout, consumption of leafy vegetables should be prohibited. Milk and dairy products from this property should also be banned and replaced by imported products and infant formulas. The internationally accepted recommended dose for KI thyroid blockade is 50 mSv. (Nuclear or Radiological Emergency Preparedness IAEA Safety Series No. GS-G-2.1, co-sponsored by WHO. IAEA, Vienna (2007), P15) 3. What is the link between dose and long-term benefits? Exposure to ionizing radiation may increase the risk of cancer. Radiation epidemiological studies of atomic bombing survivors, patients receiving radiological consultations, occupationally exposed populations, and those exposed to the Chernobyl nuclear accident in the former Soviet Union have shown that no significant radiation carcinogenic benefits were found at whole-body radiation doses below 100 mSv. Studies in the investigation of survivors of the atomic bombings in Japan have shown an increased risk of leukemia in the years following radiation exposure and an increased risk of cancer after 10 years. In the case of a nuclear accident, if radioactive iodine is deposited in the thyroid gland, it causes localized thyroid dose effects rather than systemic effects. Lessons learned from the Chernobyl accident, which resulted in more than 5,000 cases of thyroid cancer in children aged 0-18 years, indicate that radioactive iodine was the most influential factor. One of the greatest impacts of the Chernobyl nuclear accident was psychological. This was largely the result of a lack of risk communication mechanisms. Therefore, it is very important to establish a good public communication mechanism in a nuclear emergency situation. 4. Below what dose can be considered to have no health effects? Statistical epidemiological studies show that there is no significant increase in the risk of causing cancer at doses below 100 mSv. However, the linear no-threshold model of ionizing radiation is the basis of radiation protection. This means that theoretically any dose of ionizing radiation can lead to certain biological effects, but such effects have not been verified in humans. Therefore, we cannot say that that dose level is an absolute zero risk. In ionizing radiation protection should follow the principle of optimization of protection level (ALARA principle) as far as possible. 5.When do I need to take personal protective measures? What should the public be aware of? When the air is contaminated with radioactive substances, some personal protective measures are needed. Covering the nose and mouth with handkerchiefs, towels and cloths can reduce the dose from inhalation of radioactive materials by about 90%. Body surface protection can be provided by a variety of everyday clothing, including hats, hoods, raincoats, gloves and boots. Decontamination of personnel who have been or are suspected of being contaminated by radioactivity on the body surface is as simple as telling the person concerned to shower with water and to take off and store the contaminated clothing, shoes, hats, etc. until there is time for monitoring or treatment later. To prevent the spread of radioactive contamination to uncontaminated areas. 6. How to protect yourself? First of all, avoid panic, listen to the radio or watch TV in time, and act according to the instructions of the government. Stay indoors in situations where radioactive contamination may be present. Iodine tablets should be taken according to the government’s instructions. Only the government can decide whether iodine tablets are needed after assessing the status of the accident. They should not be taken solely on the basis of personal subjective judgment or out of fear. 7. Under what circumstances should food and water be controlled? When the concentration of radionuclides in food and drinking water exceeds the levels specified in the national standards, the consumption of such contaminated food and drinking water should be prohibited or restricted. The national standard divides food into two categories, one for general consumption and one for milk, baby food and drinking water; the concentration levels for different radionuclides that require intervention are specified separately. 8.When to take covert measures? What should the public pay attention to? Concealment is one of the main protective measures in the early and middle stages of an emergency with a large release of radioactive material into the atmosphere. Most buildings can reduce the inhaled dose to about half of the people inside the building. After a period of concealment and the passage of the plume, the concentration of radionuclides in the air within the concealment will rise, and ventilation is necessary to reduce the airborne concentration of radioactivity to a level equivalent to a cleaner outdoor level. Thus, for a sustained release, concealment is less effective for protection. Concealment time is generally considered to be no more than 2 days. 9. How far is it safe to evacuate? In general, the first priority is to limit the occurrence of radiation exposure. The impact of radioactive fallout is reduced primarily by evacuating or concealing the affected population. Depending on the amount of radioactive material released in the atmosphere and the prevailing meteorological conditions (e.g., wind direction, precipitation, etc.), and based on the extent of the center of the explosion, the state will determine the radius within which emergency sheltering measures should be taken.