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The Acid Rain Program – What’s it all about?

2010 April 12

We’ve heard about the problem of acid rain and all of its negative effects. So, what are we doing about it? Well, that’s where EPA’s Acid Rain Program comes into play. The Acid Rain Program, we’ll call it ARP for short, was established by Congress in the 1990 Clean Air Act Amendments. Here are the 5 Ws of the ARP:

What – A program that limits the emissions of pollutants that form acid rain. Specifically, the program reduces emissions of sulfur dioxide (SO2) and nitrogen oxides (NOx), which are the biggest contributors to the formation of acid rain.
When – The program began in 1995 and has been in place since.
Who – The ARP applies to power plants that burn fossil fuels to create electricity; so they are responsible for making the emission reductions.
Where – The program is nation-wide.
Why – To help protect sensitive lakes, streams, and forests from acid rain and to protect human health.

One of the most interesting things about the ARP is how it works. Instead of putting a limit on the amount of SO2 pollution each power plant can emit, the ARP created the world’s very first large-scale trading market that offers power plants different options as to how they want to comply with the program. This market approach is called cap and trade. Check out tomorrow’s blog post for an in depth explanation of cap and trade.

So, we’ve covered the basics of the ARP, but how do we know that it’s working? Well there are many types of monitoring programs that need to be in place to make sure the ARP is helping reduce acid rain. Think of the life cycle of acid pollution from where it starts to where it ends up (check out the figure from our April 9 blog post). It’s important for us to monitor the pollution during different parts of that cycle to determine if our pollution emission reductions are truly improving the health of acid-impaired ecosystems.  So, as part of the ARP we measure emissions of pollution at the power plants, acid rain pollution in the atmosphere, acid rain as it falls to the earth (i.e., acid deposition), and we look at the condition of lakes, streams and forests.ARP4_cover

At EPA, we want to make sure the public — you all — have access to the information we collect on the ARP. So each year we put out an Acid Rain Program progress report. The report summarizes the results of the monitoring programs listed above and looks at trends over time so everyone can see if the acid rain problem is improving.

What questions do you still have about the Acid Rain Program? If you have a chance, check out our annual progress reports. What information in these reports is the most useful to you? Explain any ideas you have for stuff you think we should report on. We would love to hear feedback from real people!

Colleen Mason is a Physical Scientist with the EPA’s Clean Air Markets Division. She works on assessing and communicating the results of the Acid Rain Program and other air market programs.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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