Acid Deposition

What is Acid Deposition? Primary pollutants such as sulfur dioxide (SO 2 )from factories and nitrogen oxides (NO x ) from cars form secondary pollutants that are acidic. These then fall as wet or dry deposition.

Acid Formation These primary pollutants mix with water to form acids! –These can fall as: Wet deposition- precipitation Dry deposition- particles and gases, which can become wet deposition when they encounter any water.

Acid rain? Normal rain has a pH of 5.6 –Due to acids formed with carbon dioxide –CO 2 and Water makes dilute carbonic acid Average pH of rain in the Eastern United States is ! –10 times as acidic as normal rain! Some California fogs have pH’s as low as 2.3 –This is the same as lemon juice!

Wet Deposition SO 2 reacts with O 2 and water vapor to form diluted sulfuric acids. NO x react with O 2 and water vapor to form diluted nitric acids. Resulting precipitation has pH of 5.5 or lower.

How does acid rain affect humans? Respiratory problems (dry deposition) Can leach chemicals such as lead and copper into our drinking water! –Lead poisoning can cause learning disabilities in children Property damage –Marble and limestone dissolve easily in very weak acids –Acid rain can even damage the clear coat on cars Decrease productivity of crops and fisheries –Celery, Radishes, Tomatoes, Onions, Spinach Beans, Alfalfa, and Oranges

How does acid rain affect humans?

How does Acid Rain Affect Freshwater Ecosystems? As pH decreases acid tolerant plankton and mosses may take over Increased levels of nitrogen and sulfur to water can cause too many nutrients in the water, which causes? Acid water leaches toxic metals, such as mercury and aluminum, out of rocks and soil, it then runs off into water, which is then absorbed by fish (bad for fish and humans) –Al slows the growth, sex organ development, and egg production of fish. It can also cause an overproduction of mucus within their gills (suffocation!) –Toxic mercury makes its way up the food chain and into our food chain Acidification can slow or inhibit decomposition. How? An overall decrease in biodiversity.

How does Acid Rain Affect Freshwater? An Acidic Lake in the AdirondacksThe growth of red-algae in an acidic lake. Below 4.5, most lakes are devoid of fish!

How Does Acid Rain Affect Soil and Plants? At first the introduction of sulfur and nitrogen can improve soil fertility, but over time it leaches nutrients. –This decreases productivity of plants Weakens trees and makes them more susceptible to severe cold, diseases, and insect attacks Leaching of alkaline nutrients: –Calcium and Magnesium –Depletes the soil’s own buffering capacity. What is meant by “buffering capacity”?

Coniferous Trees A decrease in the waxy cuticle that protects coniferous tress from excess water loss!

Why is Acid Rain a Regional Problem?

Why is acid deposition regional rather than global? Acidic components only remain in the atmosphere for a short while before they are grounded either by dry or wet deposition. Areas that are most effected are near industrial areas or areas with high traffic. Ex: Coal and Oil burning factories in Philadelphia, Pittsburgh, Chicago and West Virginia account for 1/2 of the Acid Deposition in southeast Canada Ex: 3/4 of the acid deposition in Norway, Switzerland, Austria, and Sweden are caused by industries in the UK and Germany

Why are some regions more susceptible than others? Some soil has buffers (Calcium Carbonate or limestone) that naturally occur Soils that are thin and rocky are at a greater risk = sensitive soils

The 3 R Model for Pollution Management! Replace/Reduce = Using an alternative that would replace the original primary pollutant OR using a method that would stop or reduce the use of the pollutant. Regulate = The implementation of Laws or regulations to reduce the pollutant. Restore = Fixing the environment after the effects of the pollutant.

Reducing Acid Rain! Stop burning coal! –Change from using coal to cleaner burning natural gas and renewable energy sources. Removal of sulfur from coal before it is burned ie “clean coal”…expensive, not efficient Filters on smokestacks….must be regulated Removal of Nitrogen Oxides from automobile exhaust. –How is this regulated?

Restoring Acidified Areas! Liming –Large amounts of limestone can be deposited to neutralize lakes and soils Expensive and temporary ! * $8 Billion Harmful to plankton and aquatic plants Only a Temporary Remedy - must be done annually.