What Is Clean Air?
Clean Air, both indoor and outdoor, is vital to lung health. Our Clean Air Initiative is focused on air quality problems that have a direct impact on lung health.
Ozone pollution
Ozone is a group of three oxygen molecules that serve both good and bad functions. In the lower atmosphere, the troposphere, ozone is a major component of smog. This is what people call “bad” ozone because of its harmful effects on people, materials and ecosystems. It is created when sunlight reacts with hydrocarbons and nitrogen oxides that are emitted by automobiles, auto body shops, gas stations, organic solvents and dozens of other sources. The concentration of ozone in the air also strongly correlates to many meteorological characteristics including temperature, wind speed and atmospheric stability.
Ground level ozone should not be confused with the protective ozone layer in the upper atmosphere, the stratosphere, which shields the Earth from the harmful ultraviolet rays of the sun. This is what people call “good” ozone. Over the past few years, scientists and the media have given a lot of attention to the problem of the “hole” in the ozone layer. In fact, “good” and “bad” ozone are chemically identical, it is only the location that makes the difference between the two. It is important that people do not mistake one for the other.
Particulate matter
Particulate matter, also known as particle pollution, refers to a mixture of solid particles and liquid droplets found in the air. Some particles such as dust, dirt, soot or smoke are large or dark enough to be seen with the naked eye, while other fine particles, such as acids, organic chemicals, metals, soil and dust particles and allergens, are so small they can only be detected by using an electron microscope.
With diameters of 2.5 micrometers and smaller, a size nearly 30 times smaller than a single strand of human hair, fine airborne particles come from a variety of sources including motor vehicles, power plants, wood burning stoves and fireplaces, forest fires and some industrial processes.
Coal-fired power plants
Electric utilities are a major source of air pollutants that affect lung health, including sulfur dioxide, a powerful asthma trigger, and nitrogen oxide, which is a component of ozone smog. Air quality experts nationwide have identified reducing emissions from power plants as a technologically feasible, cost-effective approach to achieving cleaner air.
Electric utilities produce 66 percent of all sulfur dioxide emissions nationwide. Even brief exposure to relatively low levels of sulfur dioxide has been repeatedly shown to trigger attacks in people with asthma. Sulfur dioxide also contributes to the formation of fine particles, and to acid rain.
Power plants are also the source of 29 percent of nitrogen oxide (NOx) emissions. NOx is a major component of ozone smog and fine particulate matter, which affect the health of millions of Americans across the country.