1. Acid Precipitation Section 12.3
Objectives:
Explain causes of acid precipitation.
Explain effects of acid precipitation.

2. Intro
Rainfall downwind
Acid precipitation and cars

3. What Causes Acid Precipitation?
Acid precipitation: any form of precipitation that contains a high concentration of acids
Caused by burning fossil fuels
Releases oxides of sulfur and nitrogen into the air (SO2 and NO2)
These gases combine with water vapor in the atmosphere, forming sulfuric acid and nitric acid.

4. pH: power of hydrogen Acids: pH < 7 Bases: pH > 7
Pure water: pH =7.0
Normal rain: pH about 5.6
Acid precipitation: pH < 5.0
Varies by location:
Eastern Europe:
Rest of Europe:
Eastern U.S.: (Lake Ontario and Lake Erie: 4.2)

5. pH Scale

6. Effects on Soil and Plants
Drop in pH of soil (acidification)
Acidic soil:
Some nutrients are dissolved
Causes aluminum and other toxic metals to be released and absorbed by plants
Aluminum causes root damage.

7. Effects on Aquatic Ecosystems
Change in water’s pH can kill aquatic plants, fish, and animals.
Acidic pH causes aluminum to leach out of soil and accumulate in fish gills so they can’t exchange oxygen and salt. (Fish suffocate!)
Acid shock: sudden change in water pH due to excess runoff of acidic precipitation (mainly in Spring)

8. Effects on Humans and Lifestyle
Toxic metals released in acidic soils (aluminum, mercury, etc.) become part of food crops, water, and fish, then we ingest them.
Possible connection between acid precipitation and respiratory problems in children
Damage to fishing and forestry industries
Can damage buildings and monuments

9. Cleopatra’s Needle

10. Challenges in Controlling Acid Precipitation
Pollutants may be released in one geographical area and fall to the ground in another.
SE Canada’s acid precipitation is formed in Ohio, Indiana, Pennsylvania, Illinois, Missouri, West Virginia, and Tennessee!
Acid precipitation falls downwind from where it is formed.

11. International Conflict

12. Know For TEST!
Section Review (p.317): 1-3, 6