What is Air Pollution?The air we breathe is made up of a mixture of gases and small particles. Pollutants in the air are chemicals or substances that are harmful to humans, other species, or ecosystems as a whole. These such pollutants can come from human (anthropogenic) sources, or from natural sources such as volcanos or dust storms. For more information visit the Weather Underground's main air pollution page.
What are the major classifications of Air Pollutants?There are two basic types of pollutants: gases and aerosols. Aerosols consist of either solid materials or liquid droplets such as sulfuric acid. Most air pollutant gases are invisible to the naked eye, with the exception of nitrogen dioxide, which has a brownish color. Even air that appears to be clean and clear contains a multitude of small solid particles. One cubic foot of air can contain millions of air pollution particles! Scientists have observed that cities can have hundreds to thousands of times more particles than rural regions.
What is ozone pollution?Ozone forms in both the upper and the lower atmosphere. Ozone is helpful in the upper atmosphere, called the stratosphere, because it absorbs most of the harmful ultraviolet light coming from the sun. Ozone found in the lower atmosphere, called the troposphere, is harmful. Ozone found here is the prime ingredient for the formation of photochemical smog. This pollutant can irritate the eyes and throat, and damage crops. Visit the Weather Underground's ozone pollution page, or our ozone action page for more information.
What is particulate matter pollution? Particulate matter (PM) pollution is composed of very small solid or liquid particles suspended in the air. Many man-made and natural sources emit PM directly or emit other pollutants that react in the atmosphere to form PM. PM is the most noticeable pollutant because it dramatically reduces visibility in urban areas. For more information, or to learn about the health effects from particulate matter, visit the Weather Underground's particulate matter pollution page.
What is carbon monoxide pollution?Carbon Monoxide (CO) is also a major urban air pollutant. It is a colorless, odorless, poisonous gas that forms during the incomplete combustion of carbon-containing fuels. Scientists estimate that in the U.S. alone, over 60 metric tons of CO enter the air annually. The Weather Underground has compiled a page that deals specifically with the topic of carbon monoxide pollution, visit this page for more information.
What is sulfur dioxide pollution?Sulfur Dioxide (SO2) pollution is produced when sulfur containing fuels are burned. High concentrations of SO2 can aggravate respiratory problems, such as asthma, bronchitis, and emphysema. In high quantities, SO2 can harm plants and cause rain to become acidic. Visit the Weather Underground's sulfur dioxide pollution page for more information.
What is nitrogen dioxide pollution?Nitrogen Dioxide (NO2) pollution forms when nitrogen in the air reacts with oxygen during the high temperature combustion of fuel. High concentrations of this pollutant can lead to heart and lung problems, as well as lowering a body's natural immune system. NO2 is a key component in producing photochemical smog and ozone pollution. The Weather Underground's nitrogen dioxide pollution page has all the information that you need to further your knowledge on this topic.
What is lead pollution?Lead has long been known as a harmful environmental pollutant, and has been called the most harmful pollutant to small children. People are easily exposed to lead pollution through the ingestion of contaminated water, food, air, soil, deteriorating paint and dust. Lead pollution is formed and emitted during the processing of metals. The highest concentration of this pollutant can be found in the vicinity of nonferrous and ferrous smelters, battery manufacturers, and other sources of stationary lead emissions. According to the American Lung Association, exposure to lead pollution can cause neurological impairments such as seizures, mental retardation, and/or behavioral disorders. Even in low amounts, exposure to lead is can cause damage to the nervous systems of fetuses and young children. The National Ambient Air Quality Standard for lead is 1.5 micrograms per cubic meter of air, averaged over a three-month period. In 1998, the EPA monitored these 5 US counties to be in violation of this standard: Philadelphia Co, PA (1.64µg/m3), Shelby Co, TN (2.02µg/m3), King Co, WA (2.03µg/m3), Madison Co, IL (2.59µg/m3), and Jefferson Co, MO (11.54µg/m3).
What cities in the world have the worst pollution?Beijing, Shanghai, Tehran and Calcutta follow Mexico City on the list of cities whose air poses greatest risk to children. Respiratory disease is now the leading cause of death for children worldwide, according to http://www.overpopulation.org/catholic.html