If you like fresh air, you're probably a big fan of the Clean Air Act and its amendments. While the air in many places is far from ideal, prior to federal legislation it was downright deadly in American cities. A clear gray sky on a summer's day in Philadelphia is a little off-putting, but it beats a smothering fog in the valleys outside Pittsburgh. After the deadly Donora smog in 1948 killed 20 and sickened thousands of others. Federal investigators were asked to come in, and determined that air pollution was in fact the killer, among other factors.
The government prefers to take baby steps when implementing positive change, rather than jumping in feet first, and tackling air pollution is no exception. The first step came in 1955 with the Air Pollution Control Act, which provided funding for research and led to the Clean Air Act of 1963 and Air Quality Act of 1967. These provided the first air quality monitoring.
The Clean Air Act of 1970 was a major step forward. It developed limits on pollution and expanded federal enforcement powers. Among the controls included were auto emissions. States were mandated to implement plans to reduce pollution.
The Amendments of 1990 aimed to reduce air pollution linked to acid rain and ozone depletion.
Looking at a picture of the summer sky over Los Angeles, it might be hard to believe the Clean Air Act is working. However, the number of ugly sky days is lower than prior to enactment. Air quality monitors in California frequently show poor quality, and geography is partly to blame. Ocean breezes carry pollution as far as the mountains, where it gets stuck and sometimes builds up for days.
 |
| Los Angeles skyline (LAist) |
Acid rain has been reduced as a result on the 1990 amendments. pH testing has shown freshwater pH levels in many areas have risen closer to neutral 7. Pure water is neutral, but in nature, water is rarely pure. Pristine rain is slightly acidic because of carbon dioxide in the atmosphere forming carbonic acid. However, the lowered pH in rivers and lakes nationwide was far lower than caused by carbonic acid. Targets of the 1990 amendments were nitrogen oxides (NOx) and sulfur dioxide (SO2). Emissions have been greatly reduced over the last 30 years, and ecosystems are continuing to slowly recover.
Information this week comes the
EPA (Clean Air Act overview),
Smithsonian Magazine (Donora), and more
EPA (acid rain). For a great visual on showing higher pH and lower NOx and SO2, check out the
National Atmospheric Deposition Program.
EPA:
https://www.epa.gov/clean-air-act-overview/evolution-clean-air-act
Smithsonian: https://www.smithsonianmag.com/history/deadly-donora-smog-1948-spurred-environmental-protection-have-we-forgotten-lesson-180970533/
EPA:
https://www.epa.gov/airmarkets/acid-rain-program
nm1 LAist:
https://laist.com/2018/10/30/why_las_smog_has_been_extra_smoggy.php
nm2 Citylab:
https://www.citylab.com/design/2012/06/what-pittsburgh-looked-when-it-decided-it-had-pollution-problem/2185/
nm3 Smithsonian
nm4 National Atmospheric Deposition Program
http://nadp.slh.wisc.edu/data/animaps.aspx
No comments:
Post a Comment