What are the hazards of PM2.5 to the human body and what should we pay attention to?

Heavy fog has appeared in many parts of the country. Among them, the air visibility in Beijing, Tianjin and South China is less than 1000 m, and the local visibility is less than 100 m. The Central Meteorological Observatory has issued several blue fog warnings. One of the main culprits in foggy days is fine particulate matter PM2.5, which is a kind of "lung accessible particulate matter" with a diameter less than 2.5 microns, which is fatal to human body. Recently, Academician Zhong Nanshan called for the publication of PM2.5 values and urged government departments to work together to control smog. The Ambient Air Quality Standard also increased the average annual and daily concentration limits of PM2.5 in basic monitoring projects for the first time. The relevant person in charge of the Ministry of Environmental Protection 165438+ 10/6 said that the new standard will be fully implemented in 20 16.

Heavy fog has appeared in many parts of the country. Among them, the air visibility in Beijing, Tianjin and South China is less than 1000m, and the local visibility is less than1000 m. The Central Meteorological Observatory has repeatedly issued blue fog warnings. Netizens joked that the cities headed by Beijing can be collectively referred to as "foggy cities" and reminded that "the air is dangerous and you need to be careful when breathing".

A research report issued by china environmental science Research Institute said: "Urban agglomerations in the Pearl River Delta, the Yangtze River, Beijing-Tianjin-Hebei, Sichuan Basin and Shenyang are increasingly polluted by fine particles in the air." It is also reported that the number of foggy days in Shanghai, Guangzhou, Tianjin and other cities accounts for 30% ~ 50% of the total number of days in a year, and China has become one of the countries with the most serious air pollution in the world. A world air quality map published by NASA shows that the average concentration of fine particles in most areas of China is close to 80 μ g/m3, which is 8 times higher than the relevant pollution indicators stipulated by the World Health Organization.

According to experts, the smog seems mild, but in fact it contains more than 20 kinds of fine particles and toxic substances harmful to human body, including acids, alkalis, salts, amines and phenols. , as well as dust, pollen, mites, influenza virus, tuberculosis, pneumococcus, etc. Its content is dozens of times that of ordinary atmospheric water droplets. What impact will fog and PM2.5 have on human health? How to deal with it?

PM2.5 is the chief culprit of "smoggy days"

When a large number of fine particles float in the air, the sky looks gray. Meteorology calls this phenomenon "smog days", and one of the main culprits of smog days is fine particulate matter PM2.5, which refers to particulate matter with a diameter less than or equal to 2.5 microns in the atmosphere, also known as particulate matter (aerosol) that can enter the lungs. It is an important indicator for monitoring the degree of air pollution internationally. Because PM2.5 is very small, it can digest light more obviously, so PM2.5 is also a very important pollutant that causes our visibility to decline now. According to the regulations of the International Meteorological Organization, fog is a collection of a large number of tiny water-absorbing particles suspended near the ground, and haze is a combination of a large number of tiny dust particles, smoke particles or salt particles suspended in the atmosphere, which can make the air turbid, and the particles that make up haze are too small to be distinguished by the naked eye.

Scientists pointed out that the main sources of PM2.5 are industrial waste gas produced by the artificial combustion of minerals such as coal and oil, tail gas emissions produced by motor vehicles, including dust, sulfuric acid, nitric acid, organic hydrocarbons and other particles scattered in the air, and cigarette smoke. These are all secondary pollutants formed through a series of photochemical reactions. The most direct side effect of these ultrafine suspended particles in the air is the haze weather. The higher the concentration, the more foggy weather.

PM2.5 is harmful to human health, especially to the elderly and children.

Medical research shows that the smaller the particles, the greater the harm to human health. Generally speaking, particles with a diameter greater than 10 micron will be blocked out of the nose; Particles with a diameter of 2.5 microns to 10 microns can enter the respiratory tract, but some of them are excreted with spitting and sneezing; However, fine particles smaller than 2.5 microns in diameter will pass through the lower respiratory tract smoothly, and particles smaller than 2.5 microns can enter the alveoli and enter the human blood vessels through the exchange of qi and blood. This is the key to the great harm of PM2.5 to human health.

A study by peking university health science center College of Public Health shows that when the daily average concentration of PM2.5 in observation points on the campus of Peking University increases, the number of emergency patients with cardiovascular diseases in the Third Hospital of Peking University, which is about 4 kilometers away, also increases. When the concentration of PM2.5 increases by 10 μ g per cubic meter, the number of emergency patients with hypertension in hospitals will increase by 8%, and cardiovascular diseases will also increase. The mortality data of lung cancer in the whole population and the average annual concentration data of total suspended particulate matter in the atmosphere show that the gray correlation between lung cancer mortality and total suspended particulate matter was the highest nine years ago, which means that the incubation period of total suspended particulate matter leading to lung cancer is about 8 years.

Winter fog is called "winter killer". American studies have found that traffic pollution can significantly hinder the development of children's lung function. Smog means death for the frail elderly.

Foggy weather can lead to respiratory diseases. In foggy weather, dust and smoke are floating in the air, and dust mites may also be suspended in the fog, which can cause acute upper respiratory tract infection (cold), acute tracheobronchitis, pneumonia and asthma attacks, and induce or aggravate chronic bronchitis. In particular, children's respiratory mucosa of nose, trachea and bronchus is tender, and the number of alveoli is small, the development of elastic fibers is poor, and the interstitial development is vigorous, which makes them more susceptible to respiratory viruses. Every time a person breathes, about 500,000 particles are inhaled into the depths of the lungs, but in polluted air, the inhaled particles are 100 times more than this. Being in foggy weather for a long time will cause tracheitis, laryngitis, pneumonia, asthma, rhinitis, conjunctivitis, allergic diseases, etc., which will have a certain impact on the growth and physique of children and adolescents. In addition, diabetic patients with poor air quality and poor resistance in foggy days are very likely to have lung and trachea infections, which will aggravate their condition.

Hazy days are more likely to cause cancer than cigarettes: Zhong Nanshan, academician of China Academy of Engineering and director of Guangzhou Institute of Respiratory Diseases, once pointed out that in recent 30 years, the public smoking rate in China has been declining, but the prevalence of lung cancer has increased by more than four times. This may be related to the increase in haze days. Not only foggy days with very low visibility will have an impact on human health, but also foggy days and cloudy days will have the same problem.

Hazy days are easy to induce cardiovascular and cerebrovascular diseases: Smoky days also have a serious impact on human cardiovascular and cerebrovascular diseases, which will hinder normal blood circulation, lead to cardiovascular diseases, hypertension, coronary heart disease and cerebral hemorrhage, and may also induce angina pectoris, myocardial infarction and heart failure. And cause pulmonary heart disease in chronic bronchitis. In addition, when the air pressure is relatively low in foggy weather, people will feel irritable and their blood pressure will naturally rise. On the other hand, in foggy days, the temperature is often low. Some patients with hypertension and coronary heart disease suddenly go from warm indoor to cold outdoor, and blood vessels expand with heat and contract with cold, which will also increase blood pressure, leading to stroke and myocardial infarction. Therefore, patients with cardiovascular and cerebrovascular diseases must take medicine on time and handle it carefully.

Long-term smog can induce psychological depression. Experts point out that continuous foggy days have an impact on people's psychology and body. Psychologically speaking, foggy days will give people a feeling of depression, which will stimulate or aggravate the state of psychological depression. In addition, due to the weak light and low air pressure in foggy days, some people will feel lazy and depressed in foggy days.

How can we prevent the damage of PM2.5 to health?

Wear a mask when going out in foggy weather. For the elderly and children, go out as little as possible in foggy weather. If you have to go out, you'd better wear a mask. For people with allergic asthma, wearing a mask is more important. Masks can prevent some dust from entering the nasal cavity and play a certain protective role.

It is not advisable to do morning exercises too early. People who have the habit of doing morning exercises should stop outdoor activities in foggy days. Because morning exercise in foggy days is easy to cause airway hyperresponsiveness. When people do morning exercises, the amount of oxygen needed by the human body increases, and harmful substances in the fog will invade the respiratory tract, resulting in insufficient oxygen supply, resulting in dyspnea, chest tightness, palpitations and other adverse symptoms. Because every day from 6: 00 to 1 1: 00 is a time when pollution is serious, and the air is cleaner at night, you might as well put your exercise at night.

Old people should do morning exercises, preferably when the sun comes out. If the sun never appears in foggy days, it is also feasible to cancel an exercise plan. Judging from the time when the sun comes out, the better time for winter exercise is 9 am. Pay attention to drink some boiled water properly and replenish water before morning exercise. In addition, don't do too much exercise in winter, and you'd better go quickly.

Children should pay attention to calcium supplementation. In foggy days, due to the decrease of sunshine, insufficient ultraviolet radiation for children, insufficient production of vitamin D in the body, and greatly reduced absorption of calcium, rickets in infants and young children will be seriously caused, which will slow down the growth and development of children.

Do a good job of personal and room hygiene after returning home. Fog seems mild, but it contains various harmful substances such as acid, alkali, salt, amine, phenol, dust and pathogenic microorganisms. Therefore, you should wash your face and expose your skin immediately when you go out in foggy days. Remember to open the window for air every day to ensure the air is fresh. Clean the room in time, clean up the sanitary corner, and don't give the soil where germs breed.

Regulate mood and eat lightly. Due to the lack of sunshine, weak light and low air pressure in foggy days, some people will feel lazy and depressed in foggy days. I suggest you keep a scientific life rule, avoid overwork, drink more water, pay attention to a light diet, eat less irritating food and eat more tofu, milk and other foods.

In addition, in order to prevent fog damage and increase the body's resistance, you can also make your own ginger and jujube soup (5-6 grams of ginger, 0/0 grams of jujube/kloc, plus two bowls of water and brown sugar) to prevent it.