Outdoors: Air pollutants can be released into the air from a variety of sources, including vehicles, industrial facilities, and power plants. Exposure to outdoor air pollution can occur when people are outdoors, such as when walking, exercising, or working.
Indoors: Air pollutants can also be released indoors from a variety of sources, including tobacco smoke, cleaning products, and building materials. Exposure to indoor air pollution can occur when people are indoors, such as when cooking, cleaning, or sleeping.
The timing of air pollutant exposure can also vary. Some air pollutants are released into the air at specific times of day or year, such as during rush hour or during the winter heating season. Others are released into the air continuously.
The types of air pollutants that people are exposed to can also vary. Some of the most common air pollutants include:
Particulate matter (PM): PM is a mixture of small particles of solid and liquid matter suspended in the air. PM can come from a variety of sources, including vehicles, industrial facilities, and wildfires.
Ozone (O3): O3 is a gas that is formed when sunlight reacts with other pollutants in the air. O3 is a major component of smog and can cause respiratory problems.
Nitrogen dioxide (NO2): NO2 is a gas that is produced by vehicles, power plants, and industrial facilities. NO2 can irritate the lungs and contribute to respiratory problems.
Sulfur dioxide (SO2): SO2 is a gas that is produced by power plants, industrial facilities, and volcanoes. SO2 can cause respiratory problems and contribute to acid rain.
Carbon monoxide (CO): CO is a gas that is produced by vehicles, power plants, and industrial facilities. CO can reduce the oxygen-carrying capacity of the blood and can cause heart problems.
Lead (Pb): Pb is a metal that is released into the air from vehicles, industrial facilities, and smelters. Pb can damage the brain and nervous system, especially in children.
Exposure to air pollutants can have a variety of health effects, including:
Respiratory problems, such as asthma, bronchitis, and emphysema
Heart problems, such as heart attacks and strokes
Cancer
Developmental problems, such as low birth weight and learning disabilities
The health effects of air pollution can vary depending on the type of pollutant, the level of exposure, and the individual's health.
