Prolonged exposure to high levels of air pollutant particles, such as PM2.5 particulate matter with a diameter of 2.5 micrometers or less , can have significant adverse effects on the human respiratory system and overall health. PM2.5 particles are small enough to penetrate deep into the lungs and even enter the bloodstream, leading to a range of health issues.1. Respiratory system effects: When PM2.5 particles are inhaled, they can cause inflammation and irritation in the airways, leading to symptoms such as coughing, wheezing, and shortness of breath. Over time, this can exacerbate existing respiratory conditions, such as asthma and chronic obstructive pulmonary disease COPD , and increase the risk of developing respiratory infections like bronchitis and pneumonia.2. Cardiovascular effects: PM2.5 particles can also affect the cardiovascular system by causing inflammation and oxidative stress, which can contribute to the development of atherosclerosis hardening and narrowing of the arteries . This increases the risk of heart attacks, strokes, and other cardiovascular events.3. Cancer risk: Long-term exposure to high levels of PM2.5 has been associated with an increased risk of lung cancer. The International Agency for Research on Cancer IARC has classified outdoor air pollution and particulate matter, including PM2.5, as a Group 1 carcinogen, meaning it is considered to be carcinogenic to humans.4. Impaired lung function and growth: Children exposed to high levels of PM2.5 may experience reduced lung function and growth, which can have long-term consequences for their respiratory health.5. Premature death: Studies have shown that long-term exposure to high levels of PM2.5 is associated with an increased risk of premature death, particularly from cardiovascular and respiratory diseases.6. Other health effects: PM2.5 exposure has also been linked to other health issues, such as diabetes, cognitive decline, and adverse birth outcomes like low birth weight and preterm birth.In summary, prolonged exposure to high levels of air pollutant particles like PM2.5 can have severe consequences for the human respiratory system and overall health, increasing the risk of respiratory and cardiovascular diseases, cancer, and premature death. Reducing air pollution and limiting exposure to PM2.5 is essential for protecting public health.