(2014 Meilie District Simulation) PM2.5 (fine particles), which are pollutant particles with a diameter less than 2.5 microns, are an important cause of haze weather.

The respiratory system consists of the respiratory tract and the lungs. After PM2.5 particles enter the lungs, they can enter the blood through the alveolar walls and capillary walls. After passing through the pulmonary circulation, they first reach the left atrium of the heart through the pulmonary veins [1]. (2) The formation of urine includes filtration of the inner wall of the glomerulus and renal capsule and reabsorption of the renal tubules. Blood enters the kidneys from blood vessels 8. Heavy metals in PM2.5 can easily cause nephrotoxicity, thus affecting the glomeruli. filtration and tubular reabsorption. (3) Blood circulation is divided into systemic circulation and pulmonary circulation. Through the systemic circulation, the blood changes from arterial blood to venous blood. From B to A in the figure, the blood changes from arterial blood to venous blood. (4) Air quality is very important to human health. Control of pollution Emissions are the fundamental measure to improve air quality. To prevent and control air pollution, we can start from the following aspects, take various measures to reduce the generation of pollutants, use various professional technologies to control pollutant emissions, improve environmental supervision, and increase law enforcement. Therefore, the answer is: (1) respiratory tract; capillaries; left atrium (2) filtration; reabsorption

(3) arteries; veins (4) Take various measures to reduce the production of pollutants and use various develop professional technologies to control pollutant emissions; improve environmental supervision and increase law enforcement. (The answer is reasonable)