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    ZME Science
    https://www.zmescience.com › ecology › the-invisible-threat-how-air-pollution-is-silently...

    The Invisible Threat: How Air Pollution Is Silently Reshaping Our …

    Why is air pollution a problem?
    2. 12 EPA, 2005 National-Scale Air Toxics Assessment (2011). Despite the dramatic progress to date, air pollution continues to threaten Americans’ health and welfare. The main obstacles are climate change, conventional air pollution, and ozone layer depletion.
    epa.gov
    Air Pollution: Current and Future Challenges | US E…

    Great progress has been made in achieving national air quality standards, which EPA originally established in 1971 and updates periodically based on the latest science. One sign of this progress is that visible air pollution is less frequent and widespread than it was in the 1970s. However, air pollution can be harmful even when it is not visible. ...

    U.S. Environmental Protection Agency

    EPA determined in 2009 that emissions of carbon dioxide and other long-lived greenhouse gases that build up in the atmosphere endanger the health and welfare of current and future generations by causing climate change and ocean acidification. Long-lived greenhouse gases, which trap heat in the atmosphere, include carbon dioxide, methane, nitrous ox...

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    While overall emissions of air toxics have declined significantly since 1990, substantial quantities of toxic pollutants continue to be released into the air. Elevated risks can occur in urban areas, near industrial facilities, and in areas with high transportation emissions.

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    The ozone (O3) layer in the stratosphere protects life on earth by filtering out harmful ultraviolet radiation (UV) from the sun. When chlorofluorocarbons (CFCs) and other ozone-degrading chemicalsare emitted, they mix with the atmosphere and eventually rise to the stratosphere. There, the chlorine and the bromine they contain initiate chemical rea...

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