Over a period of 5 months, a high-flow sampler was used to collect fine particulate matter PM2.5 in a non-industrial area using glass fiber filter paper to make a particulate suspension, and PM2.5 suspension was injected into the trachea of experimental rats to establish a lung injury model and observe the signs, lung weight ratio, key biochemical indicators and the degree of lung injury in different control groups. PM2.5 can cause lung cancer It was found that PM2.5 not only affects the phagocytosis of alveolar macrophages after entering lung tissue, but also affects the permeability and fluidity of lung epithelial cell membranes, causing leakage of cell contents and leading to cell death. At the same time, PM2.5 can cause changes in the biochemical composition of lung tissue and the release of inflammatory factors, inducing inflammation, and severe and persistent inflammation can cause tissue proliferation and fibrosis, leading to lung diseases and even lung cancer. According to the International Agency for Research on Cancer (IARC) under the World Health Organization, there is sufficient evidence that exposure to outdoor air pollution can cause lung cancer, and the deeper the exposure to particulate matter and air pollution, the greater the risk of developing lung cancer. According to the latest data from the International Agency for Research on Cancer, 223,000 people died of lung cancer in 2010 due to air pollution. According to the 2012 China Tumor Registry Annual Report released by the National Tumor Registry, there are about 3.12 million new tumor cases in China every year, with an average of 8,550 people per day, and 6 people are diagnosed with cancer every minute nationwide, while lung cancer is the first malignant tumor. In the past 30 years, the mortality rate of lung cancer in China has increased by 465%, becoming the fastest rising cancer and has replaced liver cancer as the first cause of death in China. 6 days “fresh lung” to “black lung” and can not be reversed The study found that after 6 days (144 hours) of PM2.5 drip injection in rats, the lung tissue became hard, inelastic, dark red, grayish at the edges, and lung The lung tissues had visible black particulate matter diffusion, commonly known as “black lung”. Professor Song Weimin, director of the Department of Environmental Health, School of Public Health, Fudan University, and a doctoral supervisor, said in an interview, “Once the damage to the lungs caused by PM2.5 particles is formed, the cost of drugs and time for treatment will increase greatly. The difficulty of complete elimination is greatly increased, and there is almost no possibility of reversal.” PM2.5 as a particle itself or a carrier, can carry sulfur dioxide and even viruses, into the human alveoli and macrophages engulfed, and thus remain there forever. What should we do to prevent it for the health of our families?