Exposure to fine particulate matter can lead to a variety of health effects. For example, numerous studies link particle levels to increased hospital admissions and emergency room visits, and even to death from heart or lung diseases. Both short-term and long-term particulate matter exposures have been linked to health problems.
Short-term exposures for several hours or several days can aggravate lung disease, causing asthma attacks and acute bronchitis, and may also increase susceptibility to respiratory infections. To those with heart disease, short-term exposures have been linked to heart attacks and arrhythmias. Long-term exposure has been associated with problems such as reduced lung functioning and the development of chronic bronchitis and even premature death.
PM2.5 is the major cause of reduced visibility or haze in parts of the United States, including national parks and wilderness areas. Fine particulate matter can be carried long distances by wind and then settle on the ground or in the water. The settling or deposition can make water bodies acidic and can damage sensitive forests and farm crops.