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What is Air Pollution?
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What is Air Pollution? Air pollution consists of gases, solid particles, and aerosols that change the natural composition of the atmosphere. Some gases that are normal components of clean air, such as carbon dioxide, become dangerous when concentrations are higher than normal. Air pollution has the potential to be harmful to human health and to damage other parts of the environment, including soil and water. Air pollution can come from two sources: natural and human (anthropogenic). Natural sources can include forest fires, trees and plants, and even sea salt in coastal areas. Anthropogenic pollution occurs from a wide range of human activities, such as car and truck exhaust, industrial processes, power plants, mining activities, and landfills. What governs air pollution? The Clean Air Act (CAA) is the federal law that governs air pollution and efforts to improve air quality. The CAA sets standards for how much of certain pollutants can be in the air. These standards are health-based, meaning the amount of pollutants in the air is not supposed to harm human health. The goal of these standards is to ensure that everyone has the same basic health and environmental protections Half of all Georgians now live in areas with air that may be harmful to their health. The air pollutants of concern in Atlanta are ground-level ozone and particulate matter. Ground level-ozone (smog): Ozone can be good or bad depending on where it is located. Ozone in the stratosphere high above Earth protects human health and the environment, but ground-level ozone is a serious health concern. Ozone is produced by a combination of two pollutants, nitrogen oxides (NOx) and volatile organic compounds (VOCs), from many sources, including cars and trucks, smoke stacks, paints and solvents, and even trees. These smog-forming pollutants react with one another in the atmosphere in the presence of sunlight to form ground-level ozone. Ozone levels can vary throughout the day, but the highest concentrations tend to occur between 2 and 7 pm. Ground-level ozone increases throughout the day as temperatures rise. May 1 – September 30 is Georgia’s official ozone season, but unhealthy ozone levels can happen anytime there is enough heat and sunlight to form ozone in the atmosphere. Until 2004, Atlanta had only been trying to meet the old CAA ozone standard, which is known as the 1-hour standard. In 2004, however, a new, more protective ozone standard became effective. This new standard is called the 8-hour standard. One of the differences between the two standards is the time period over which the level of ozone in the air is measured (one hour v. eight hours). Atlanta has never met, or “attained”, the 1-hour standard and is therefore classified as a “severe” non-attainment area. Atlanta also does not meet the new 8-hour standard and is classified as a “marginal” non-attainment area. The state is developing plans to bring Atlanta into compliance with both the 1-hour and 8-hour standard. Atlanta says it will be able to meet the 1-hour standard by 2005. Atlanta is required to meet the 8-hour standard by 2007. Particulate matter (PM): this is the term for particles found
in the air, including dust, dirt, soot, smoke, and liquid droplets. Particles
can be suspended in the air for long periods of time. Some particles are
large or dark enough to be seen as soot or smoke. Others are so small
that they can only be detected with an electron microscope. Areas in Georgia in violation of the national, CAA standards for particulate matter pollution will be finalized in December of this year. Five counties in metro Atlanta will likely be designated as non-attainment areas along with several other counties throughout the state. While ozone violations are typically associated with the hot spring and summer months, unhealthy levels of particulate matter can happen in any time of year. In addition to public health concerns, particulate matter can corrode metals and building facades, inhibit the growth of plants, and reduce visibility. Sources: Georgia Institute of Technology, American Lung Association, Clean Air Campaign, U.S. Environmental Protection Agency Air Pollution Links for Students http://www.arb.ca.gov/knowzone/knowzone.htm http://www.sk.lung.ca/content.cfm/kids http://www.smogcity.com/welcome.htm http://www.energyquest.ca.gov/ http://www.planetpolluto.com/index1.html http://www.niehs.nih.gov/kids/baylor/homeair.htm http://www.epa.gov/ozone/science/missoz/index.html http://www.epa.gov/airnow/aqikids/index.html http://www.ozoneactionday.org/kidozone.asp List prepared by students of Centennial Place Elementary School
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