Sources of toxic particles in cities:
First: it's automobile exhaust. Large vehicles that use diesel are "recidivists" who emit PM 10, including buses, shuttle buses of various units and large transport trucks. Sources of toxic particulate matter in cities: firstly, automobile exhaust. Cars that use diesel are "habitual criminals" who emit particles. Small cars that use gasoline emit gaseous pollutants, such as nitrogen oxides, which are easily converted into secondary particulate pollutants in foggy days, aggravating smog.
Vehicle exhaust is the main component of smog particles. According to the latest data, motor vehicle exhaust accounts for 22.2%, coal combustion accounts for 16.7%, dust accounts for 16.3%, and industry accounts for 15.7%. However, with the development of automobile technology and the improvement of oil quality, environmental managers have found that motor vehicle exhaust does not play a decisive role in the formation of haze weather. However, as some cities with large car ownership, managers still need to control vehicle emission standards to avoid the formation of haze weather.
Second: the waste gas produced by burning coal for heating in winter in the north.
Third: the waste gas emitted by industrial production. For example, metallurgy, kilns and boilers, electromechanical manufacturing, automobile repair and paint and building materials production produce a lot of waste gas from kiln combustion.
Fourth: Dust generated by construction sites and road traffic.
Fifth, the particle size of growable particles, bacteria and viruses is equivalent to PM0.1-PM2.5. When the humidity and temperature in the air are appropriate, microorganisms will attach to particles, especially oil fume particles, which will adsorb oil droplets and transform them into more microorganisms, which will increase the growth of biotoxic substances in smog.
6. Dust "smog" will also be produced in home decoration. Indoor dust is pervasive, which is not only harmful to the health of staff and users, but also increases the cleaning burden. When the dust is serious, it also brings many hidden dangers to the decoration project.
In addition to meteorological conditions, the increase of atmospheric particulate matter (including coarse particulate matter PM 10 and fine particulate matter PM2.5) caused by industrial production, vehicle exhaust emissions and coal burning in winter is an important factor of smog. At present, the level of pollutant discharge in many cities is at a critical point, which is very sensitive to meteorological conditions. When the diffusion conditions are good, the air quality can reach the standard, and once adverse weather conditions are encountered, the air quality and visibility will drop immediately.
climatic factor
"There is a difference between fog and haze. Fog refers to the weather phenomenon that the visibility is lower than 1 km due to the condensation of suspended water vapor in the atmosphere; The formation of smog is mainly the result of a large number of suspended particles in the air and meteorological conditions. There are three reasons:
First, the phenomenon of static wind in the horizontal direction has increased.
The higher the buildings are built in the city, the obstruction and friction of airflow passing through the urban area will be obviously weakened. The increase of static wind phenomenon is not conducive to the diffusion and dilution of suspended particles in the atmosphere, and it is easy to accumulate around urban areas and suburbs.
Second, the vertical direction is reversed.
The inversion layer is like a pot cover over a city. This inversion phenomenon that the upper air temperature is higher than the lower air temperature limits the vertical movement of the lower air, making it difficult for suspended particles in the air to drift to the upper air and be blocked at the lower air and near the ground.
Third, the increase of suspended particulate matter and organic pollutants in the air. With the growth of urban population and industrial development, the number of motor vehicles has surged, resulting in a large increase in pollutant emissions and suspended solids.
Preventive measures:
Open the window less in foggy days. When going out, you must wear a mask, drink plenty of water, soak chrysanthemum tea and other Chinese herbal teas to prevent diseases, eat more fruits, and thoroughly clean your skin and hair after coming home from the outside. In addition, the elderly who like morning exercises and shopping in the food market should pay attention to reducing going out, because smog is extremely harmful to the health of the elderly.
wear a mask when going outside
Drink more tea.
Appropriate vitamin d supplementation
Have a light diet and drink plenty of water.
Eat more vegetables
Minimize going out in foggy days.
Pay attention to the speed when driving.
When going out, do a good job of self-protection, wear a special anti-fog PM2.5 mask and anti-fog nose mask, filter PM2.5, and breathe fresh air anytime and anywhere.
Avoid exercising in foggy days. You can do morning exercises after the sun comes out. You can also switch to indoor sports.
The patient insisted on taking medicine. Patients with respiratory diseases and cardiovascular and cerebrovascular diseases should insist on taking medicine on time in foggy days.
Don't close the window too tightly. You can choose to open the window for a short time at noon with sufficient sunshine and less pollutants.
Try to stay away from the road. The concentration of pollutants is the highest when large cars enter the city during peak hours and at night.
Supplement calcium and vitamin D, and eat more tofu and Sydney.
Danger:
1, harm to human body:
(1) on the respiratory system.
The composition of smog is very complex, including hundreds of atmospheric chemical particles. Among them, aerosol particles smaller than 10 micron are harmful to health, such as mineral particles, sea salt, sulfate, nitrate, organic aerosol particles, fuel, automobile exhaust, etc., which can directly enter and adhere to human respiratory tract and alveoli. In particular, submicron particles will be deposited in the upper and lower respiratory tract and alveoli respectively, causing acute rhinitis and acute bronchitis. For patients with chronic respiratory diseases such as bronchial asthma, chronic bronchitis, obstructive emphysema, and chronic obstructive pulmonary disease, smog weather will make the condition acute or acute. Staying in this environment for a long time will also induce lung cancer.
(2) Effects on cardiovascular system.
Hazy days also have a serious impact on cardiovascular and cerebrovascular diseases, which will hinder normal blood circulation, lead to cardiovascular diseases, hypertension, coronary heart disease, 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.
(3) Hazy weather will also lead to the weakening of ultraviolet rays in the surface layer, which can enhance the activity of infectious bacteria in the air and increase infectious diseases.
(4) It is not conducive to children's growth. 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.
(5) Affect mental health.
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.
(6) affecting reproductive capacity.
Studies have shown that the success rate of sperm in vitro fertilization may be reduced in people who have been exposed to high concentrations of polluted air for a long time. The researchers also found a link between toxic air and the decline of male fertility.
20 13 1 1.5 The Green Paper on Climate Change: Report on Coping with Climate Change (20 13) jointly issued by China Academy of Social Sciences and China Meteorological Bureau pointed out that in recent 50 years, the smog weather in China has generally shown an increasing trend. Among them, the number of foggy days decreased significantly, the number of haze days increased significantly, and the process of persistent haze increased significantly.
Haze weather will have a significant negative impact on climate, environment, health and economy, such as acid rain and photochemical smog in urban atmosphere, which will reduce atmospheric visibility and hinder air, water and land traffic; Increase mortality, aggravate chronic diseases, aggravate respiratory and heart diseases, change lung function and structure, affect reproductive capacity and change human immune structure.
2. Harm to ecological environment and traffic:
(1) affects traffic safety.
In foggy days, due to poor air quality and low visibility, traffic jams and traffic accidents are easily caused. In daily driving, you should observe the road conditions to avoid danger.
(2) Hazy weather is more likely to cause cancer.
In foggy days, the light is seriously insufficient, the ultraviolet rays near the bottom are obviously weakened, and the bacteria in the air are difficult to kill, thus greatly increasing the probability of infectious diseases. Zhong Nanshan, academician of China Academy of Engineering and director of Guangzhou Institute of Respiratory Diseases, once pointed out at a forum that in the past 30 years, the smoking rate of the public in China has been declining, but the prevalence of lung cancer has increased 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.
(3) Affect the ecological environment.
Haze weather has an important impact on roads, railways, aviation, shipping, power supply systems and crop growth. Fog and haze will reduce air quality, affect the ecological environment and bring great harm to human health.