Acid Rain

Questions What’s the pH of normal rain? Acid rain? How does acid rain form? What are the effects of acid rain? What can be done about acid rain?

Normal Rain Normal rain is slightly acidic Pure water has a pH of 7.0 Normal rain is about 5.6-7.0 Anything below 5.6 is considered acidic

What is Acid Rain? How Does it Form? Precipitation with a pH lower than 5.6 is considered acidic These particles can travel long distances on wind currents Acidic particles remain in the atmosphere for 2–14 days, depending on wind, precipitation, and other weather patterns. By combining with water vapor, these particles form acids which fall to the earth as acid rain

Acid Rain The acidic substances return to the earth in one of two forms: Wet: falls as acidic rain, snow, fog, and cold vapor Dry: falls as acidic particles

What Ever Happened to Acid Rain? In the 1980s, acid rain received a lot of media attention. Although we don’t hear about acid rain as much these days, it is still a problem that deserves our attention.

Acid Rain pH measurements in relation to major coal-burning and industrial plants.

Where does acid rain come from? Acidic particles that form acid rain come from power plants (especially coal power plants) Cars also release acid rain causing pollution

Acid Rain Effects Acid rain can cause or worsen respiratory disease, attack metallic and stone objects, increase clouds, and kill fish. Large amounts of money are spent each year to clean and repair monuments and statues damaged by acid rain Acidified lakes kill fish Many lakes in northern Europe and the eastern U.S. have few, if any, fish due to decreased pH.

How Does Acid Rain Effect Our Lives? Poor forest/crop health due to acid in the soil

How Does Acid Rain Effect Our Lives? Acidification of lakes and streams can lead to the death of aquatic life, such as trout and bass

How Does Acid Rain Effect Our Lives? Acidity can leach heavy metals like mercury out of the soil, causing toxic levels to build up in the fish we eat

How does acid rain effect our lives? Acid rain dissolves limestone and other soft stones, leading to erosion and the destruction of statues and buildings

Plants and Acid Deposition Acid deposition can destroy some soil nutrients, release toxins into soil, and weaken plants Effects of acid rain on plants is caused partly by chemical interaction in the soils. Herbivores that eat these plants can also develop calcium deficiencies. Weakened trees are more vulnerable to diseases. The mountaintop trees are those that are most harmed by acidic rain because they are also growing in thin soils

Downwind Acid Deposition Acid rain is a problem in areas downwind from coal-burning plants and urban areas. Some areas have basic compounds in the soil that act to neutralize some acids. Many acid-producing chemicals generated in one country end up in other countries due to winds.

What Can be Done About Acid Rain? Prevention: Reduce air pollution by improving energy efficiency and increasing renewable resources Use natural gas/low sulfur coal Cleanup Add lime to neutralize acidified lakes and soils

The Future A number of prevention and control methods can reduce acid deposition, but they are politically difficult to implement. The best approaches are those that reduce or eliminate the chemicals that cause acid rain