Acid Rain - What You Should Know

It's something that we've all heard about, but many of us don't know what "acid rain" really is or why it negatively impacts our environment. To broaden general knowledge, and as inspiration to generate action, we’ve listed the basics of acid rain, what causes it, and what everyday folks can do to stop it.

Acid Rain is a broad term used to describe how acid falls from the sky. It can be wet or dry. It can be in the form of clouds, rain, hail, fog, snow or even dust.

Two pollutants cause Acid Rain: Sulfur dioxide (SO2) and Nitrogen Oxide (Nox). Two-thirds of all SO2 and ¼ of NOx are byproducts of the electric power generated every day by plants all over the world—more specifically, these contaminants are produced by the burning of fossil fuels such as coal. The biggest concentrations of Acid Rain are found over the United States and Canada.

Acid Rain occurs when these two pollutant gases react in the atmosphere with oxygen, water and other chemicals to form various acidic compounds. Sunlight exacerbates most of these reactions and the result is a mild solution of sulfuric and nitric acid.

If you remember back to chemistry class, everything has a pH. Pure water has a pH of 7.0. Normal rain is slightly acidic with a pH of 5.5. Statistics show that as of the year 2000, the most acidic rain falling in the United States had a pH of 4.3. Over time, the pH of lakes and streams change due to acidic rainfall. If the pH of a lake or stream falls under 5.5, several things happen: fish cannot reproduce, young fish have a hard time staying alive, deformities become more common and fish die of suffocation. If the pH falls under 5.0, the fish population will die off completely.

The effects of Acid Rain also include damage to forests and soil. The acidic compounds in the rainfall or melting snow change the chemistry of the soil. This leads to the stripping of vegetation and ultimately, less habitat to support the ecosystem.

There is no "quick" solution to stopping or reversing the effects of Acid Rain. It may take years, or even decades, for an ecosystem to recover. Some conservation organizations are using lime to help neutralize the acid rise in watersheds. However, this is costly and therefore not done extensively, has repercussions of its own and is more of a short-term fix.

Acid Rain is also harmful to architecture and transportation. The acidic components turn marble to a crumbly gypsum, and cause bridges and other structures to corrode and deteriorate. This corrosion problem applies to planes and trains as well, which results in increased maintenance costs and potentially hazardous situations.

Acid Rain takes its toll on our historic artifacts. The ventilation systems of most buildings cannot filter out acidic particles in the air. These particles are destroying works of art, including vintage books and clothing, flags, tapestries and other antiques.

Acid Rain also affects human health. The most serious side effect is respiratory problems, including asthma, dry cough. Other health problems include headache, eye, nose and throat irritation. An indirect effect is the concentration of toxic metals. Toxic particles of mercury and aluminum find their way into fruits, vegetables, and grasses. Once eaten by animals, these toxic particles are retained in their organs, and although this poses no threat to the animal, it does pose a threat to humans who consume them. Mercury has been linked to brain damage (especially in children), and aluminum is a suspected contributor to Alzheimer's disease.

So, what can we do about it? Well, a lot. Here are simple ways that you can make a difference they really do work!

1. Conserve electricity. Turn off lights, use compact fluorescent bulbs, turn off the TV.
2. When replacing an appliance, purchase those with an Energy Star rating. This goes for lighting as well.
3. Keep the thermostat at 68F in the winter and 72F in the summer.
4. Insulate your home. If you can, replace your windows with double pane glass. Don't forget to insulate your hot water heater. It's easy to do and it'll save you quite a bit on your energy bill.
5. Have your local utility company visit your home for a free energy inspection. They may recommend insulating doors, fixing a leaky duct system and installing a programmable thermostat.
6. Car pool when you can. This includes driving kids to practices, parties, etc.
7. Explore alternative means of transportation. Dust off your bike or break out the rollerblades. Take the bus or the train. Even just one day a week makes a huge difference.
8. When it's time to purchase a new vehicle, buy one with low NOx emissions (most car manufacturers websites have this information).
9. Maintain existing vehicles including off-road vehicles. This helps minimize emissions and maximizes fuel use.

For Earth Day, do an experiment with your child or friend to test the acidity of your local watersheds. Check out the EPA's web site for step-by-step instructions. They're easy, fun and may be quite enlightening.

For more information, visit these websites:

The ABC's of Acid Rain
EcoNet
Encyclopedia of the Atmospheric Environment