1. Acid Deposition

2. Acid Rain What is it? Why do we care?

3. Acid Rain: History Evidence of increased pH level in the atmosphere can be found in glacier ice. The Ice show a sudden decrease in pH from the start of the Industrial Revolution

4. What is Acid Rain Term first used in 1872 by a Scottish chemist, Angus Robert Smith The more accurate name is acid deposition –“Acid rain” includes both wet and dry acidic deposits Acid deposition refers to all types of precipitation--rain, snow, sleet, hail, fog--that is acidic in nature Acid deposition is precipitation with a pH lower than 5.6

5. What is Acid Rain? Acid Rain is formed when particles of gases, such as Nitrogen oxides NO x and Sulphur dioxide SO 2 mix with water droplets in clouds to form diluted acids.

6. Examples When CO 2 reacts with water, carbonic acid is formed. When SO 2 reacts with water, sulfurous acid is formed. When NO 2 reacts with water, nitric acid is formed.

7. Acidity Acidity is measured on the pH scale Each drop is a tenfold increase in acidity Normal rainfall is about 5.6 In some areas including Ontario, rain has a pH of 4 or less

8. Sources of Acid Deposition Sulfur dioxide and nitrogen dioxide particles are emitted from utility plants, especially coal-fed electric plants Automobiles also emit acid rain causing pollution Atmospheric pollutants do not recognize international boundaries, and therefore pollutants put into the atmosphere in one area might affect a different region.

9. Sources of Acid Deposition SO² –Power plants –Iron smelters –Other heavy industry –Volcanoes NO 2 –Engine Exhaust –Agricultural lands Worldwide: Natural: 75-100 million tons per year (volcanoes) Human sources: 75-100 million tons per year But in Europe and N. America, human sources contribute 95% of total load

10. Sources of Acid Deposition

11. Effects of Acid Deposition

12. Acid Deposition effects: –BIOLOGICAL: Forestry, fisheries, wildlife, and farming –ANTHROPOLOICAL: buildings and other structures, vehicles, and human health

13. Plants and Forests

14. 1. Effects on Forests Damages leaves and needles reduce tree's ability to withstand cold inhibits plant germination depletes nutrients from soils.

15. Acid rain affects animals in the water.

16. 2. Effects on Lakes and Rivers increases acidity Cannot support variety of life –Plants grow best between pH 7.0 and 9.2 –At pH 6, freshwater shrimp cannot survive. –At pH 5.5, bottom-dwelling bacterial decomposers begin to die –Below a pH of about 4.5, all fish die. –Populations of water birds dwindle with loss of fish

18. Effects on Lakes Some life benefits from the increased acidity. –i.e Lake-bottom plants and mosses, and blackfly larvae. Some lakes with limestone rock are able to neutralize acid –Eastern Canada is underlain by granite, therefore cannot neutralize acids. According to Environment Canada, 150 000 lakes are being damaged in eastern Canada,

19. Areas (In Black) With Low Acid-neutralizing Capacity

20. 3. Effects on Farming In eastern Canada, particularly Ontario, 84% of productive farmlands affected by acid rain. Root systems unable to absorb nutrients crop yields fail millions of dollars are lost.

21. Effects on Building and Vehicles Causes corrosion of buildings, monuments, stained glass, railroad line, airplanes, cars, steel bridges and other man-made structures sulfur pollutants react with minerals in stone to form a powdery substance that is washed away by rain (especially sandstone or limestone, or marble) This powdery substance is called gypsum.

23. Sandstone portal Figure on Herten Castle in Ruhr district of Germany. Sculpted 1702; photographed in 1908.

24. Same sandstone portal figure photographed in 1969.

25. 4. Effects on Human Health causes toxic metals to break loose from their natural chemical compounds. toxic metals can be absorbed by the drinking water, crops, or animals that human consume. Can cause nerve damage to children or severe brain damage or death. –Scientists believe that one metal, aluminum, is suspected to relate to Alzheimer's disease.

26. Effects on Human Health respiratory problems sulfur dioxide and nitrogen oxide emission can cause dry coughs, asthma, headaches, eye, nose, and throat irritation Acid rain can aggravate a person's ability to breathe and may increase disease which could lead to death.