Recently, the health hazards of haze pollution have become a hot topic of discussion. So, what are the health hazards of haze? What protective measures should be taken in haze days? What are the effects of PM2.5 on health? PM2.5 refers to suspended particulate matter with an aerodynamic equivalent diameter of less than or equal to 2.5 micrometers, also known as particulate matter that can enter the lungs. It has a small particle size and can carry many heavy metal ions (such as lead, cadmium, arsenic, etc.), chemical substances (such as sulfate, formaldehyde, etc.), as well as toxic and harmful substances such as bacteria and viruses. PM2.5 can enter the bronchioles and alveoli through the respiratory tract, enter the entire circulatory system, damage the respiratory system, destroy the immune system, cause respiratory, cardiovascular and cerebrovascular diseases, and have a serious impact on people's daily travel and life. Air PM2.5 particles have a small size and are prone to settling in the alveolar area. The atmospheric particulate matter entering the respiratory tract can damage the defense function of the respiratory tract, impair lung function, cause diseases such as cough, sputum, chronic bronchitis, emphysema, induce or worsen inflammation, and also cause the occurrence and worsening of asthma symptoms in children and adults. PM2.5 will stimulate the vagus nerve in the lung, causing autonomic nervous system disorder and affecting the heart, causing cardiac toxicity, such as heart rate variability change, myocardial ischemia, myocardial infarction, arrhythmia, atherosclerosis, etc. PM2.5 can cause blood system toxicity, abnormal blood coagulation function, and increase blood viscosity in the body, leading to cardiovascular events such as atherosclerosis and myocardial infarction, which is a potential risk of vascular accidents. There are many harmful substances such as heavy metals and polycyclic aromatic hydrocarbons attached to PM2.5, which can damage genetic material and interfere with normal cell division, disrupt the body's immune function, and cause the occurrence of cancer and deformities. It can easily lead to fetal intrauterine growth retardation and low birth weight, and toxins can also pass through the placenta, directly poisoning the fetus, especially in early pregnancy. Scientific research data shows that the harm of PM2.5 to human health is complex and diverse, and some harmful effects have not yet been fully recognized by humans. How to Protect Your Health in Haze Days: Eight Key Points for Self Protection? We should do the following: 1. Wear a mask. It can effectively block the direct contact of pollutants in haze with the mouth and nose, which is a direct and effective prevention method. It is best to purchase masks from a reputable medical supplies store. 2. Wear a hat. Hair can adsorb pollutants, so wearing a hat before going out can reduce hair contamination with more fine particles. 3. Wear long clothes. It is recommended to cover the skin on the surface of the body as much as possible, reduce the area of contact between the skin and harmful air, and wear a long coat in winter, which is both warm and healthy. 4. Reduce going out. Contact with haze can be directly isolated, especially for the elderly and children, and outdoor activities should be minimized as much as possible. 5. Remember "short, flat, and fast" for outdoor activities. It is very necessary to reduce the time spent outdoors in hazy weather, following the principles of short stops, peaceful breathing, and brisk walking. 6. Maintain good personal hygiene. When working or going out to do other things on hazy days, it is important to promptly maintain personal hygiene after returning home. 7. Go inside and wash your face and hands. After fully armed staying outdoors, Pi