How does smog harm human health?

What is smog?

Haze, as its name implies, is a combination of "fog" and "haze". Haze is the result of the interaction between human activities and specific climatic conditions, so the occurrence of smog is more common in cities. Among them, fog is the condensation of water vapor in the air into fine water droplets suspended in the air, thus reducing visibility. Haze, also known as haze and ash haze, refers to the turbidity caused by a large number of particles such as smoke and dust suspended for unknown reasons. The core substance of smog is dust particles suspended in the air, which are called aerosol particles in meteorology. PM2.5 particulate matter is the main component of smog, which is the most harmful to human body and the "culprit" leading to smog weather. Solving the problem of PM2.5 in the air is the key to control air smog pollution.

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Causes of health hazards caused by smog

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PM2.5 refers to suspended particles with aerodynamic diameter less than or equal to 2.5 microns, also known as particles that can enter the lungs. It has small particle size and large specific surface area, and can carry a variety of toxic and harmful substances such as heavy metal ions (such as lead, cadmium, arsenic, etc. ), chemicals (such as sulfate, formaldehyde, etc. ) and bacteria and viruses.

PM2.5 can enter bronchioles and alveoli through the respiratory tract, enter the whole blood circulation system, damage the respiratory system, destroy the immune system, cause respiratory system, cardiovascular and cerebrovascular diseases, and have a serious impact on people's daily travel and life.

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What are the health hazards of air smog pollution?

Air PM2.5 is small in particle size and easy to deposit in alveolar area. Atmospheric particles entering the respiratory tract will destroy the defense function of the respiratory tract, damage lung function, cause cough, expectoration, chronic bronchitis, emphysema and other diseases, induce or aggravate inflammation, and also cause asthma and aggravate symptoms in children and adults. PM2.5 can stimulate pulmonary vagus nerve, cause autonomic nervous system disorder and spread to the heart, and cause cardiotoxicity, such as changes in heart rate variability, myocardial ischemia, myocardial infarction, arrhythmia and atherosclerosis. PM2.5 can cause blood system toxicity, abnormal blood coagulation and increased blood viscosity, leading to cardiovascular events such as atherosclerosis and myocardial infarction, which is a potential hidden danger of vascular accidents. Many harmful substances such as heavy metals and polycyclic aromatic hydrocarbons are attached to PM2.5, which can damage genetic material, interfere with normal cell division, destroy immune function, and cause cancer and teratogenesis. It is easy to cause intrauterine growth retardation and low birth weight, and poisons can also directly poison the fetus through the placenta, especially in the early pregnancy. Scientific research data show that the harm of PM2.5 to human health is complex and diverse, and even some harmful effects have not been fully recognized by human beings.