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ACID RAIN
Tuesday, March 12, 2013
Hydrologic cycle
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Acid Rain - Wet deposition pH < 5.3
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Dry deposition: the falling of small particles and gases to the earth without rain or snow
Dry deposition can be washed away from surfaces such as buildings, cars and trees during rainstorms.
When this happens, the runoff water contains acid from both the rain (wet deposition) and dry deposition, making the combination more acidic than the falling rain alone.
The combination of acid rain (wet deposition) and dry deposition, is
called ACID DEPOSITION
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Types of Acid Rain
Pollutant emitted + Water in atmosphere Pollution (acid rain)
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Types of Acid Rain
1. SO2(g) + H20(l) H2S03(aq) – sulfurous acid
Pollutant emitted + Water in atmosphere Pollution (acid rain)
Tuesday, March 12, 2013
Types of Acid Rain
1. SO2(g) + H20(l) H2S03(aq) – sulfurous acid2. SO3(g) + H20(l) H2S04(aq) – surfuric acid
Pollutant emitted + Water in atmosphere Pollution (acid rain)
Tuesday, March 12, 2013
Types of Acid Rain
1. SO2(g) + H20(l) H2S03(aq) – sulfurous acid2. SO3(g) + H20(l) H2S04(aq) – surfuric acid3. N02(g) + H20(l) HN02(aq) + HN03(aq) – nitrous and nitric acid
Pollutant emitted + Water in atmosphere Pollution (acid rain)
Tuesday, March 12, 2013
Types of Acid Rain
1. SO2(g) + H20(l) H2S03(aq) – sulfurous acid2. SO3(g) + H20(l) H2S04(aq) – surfuric acid3. N02(g) + H20(l) HN02(aq) + HN03(aq) – nitrous and nitric acid4. CO2(g) + H2O(l) H2CO3(aq) – carbonic acid
Pollutant emitted + Water in atmosphere Pollution (acid rain)
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NATURAL FORMS OF POLLUTANTS THAT INFLUENCE ACID DEPOSITION
Old Faithful @ Yellowstone natural Park
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Effects of Acid Rain?
a) chemical change reduces soil fertility b)retards tree growthc) kills organisms in lakes & streams d) corrodes exposed metal surfacese) leaches toxic chemicals from the soil f)breaks down stone and limestoneg) damages or destroys aquatic ecosystems
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Effects of Acid Rain on Humans?Acid rain looks, feels, and tastes just like clean rain. Swimming in an acid lake is no more dangerous to humans than walking or swimming in clean water. However, breathing air that contains the pollutants that cause acid rain can damage health.SO2 (Sulfur dioxide), nitrogen oxides (NOx) and particulate matter all irritate and even damage our lungs.
Yale University - Environmental Performance Index (Air quality)http://epi.yale.edu/dataexplorer/indicatorprofiles?ind=eh.air
Poor air quality in China = Acid rain in Japan
Wind
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What is being done?
Regulations and agreements have also been set by governments that require that acceptable levels of pollutants be achieved
The concentration of chemicals in the environment can be changed using different techniques:
Dispersion: is the scattering of a substance away from its source.Dilution: reduces the concentration of a pollutant by mixing it with large quantities of air or water
-Canada & US agreed to reduce industrial exhaust emissions by 10% by the year 2000. -exhaust emissions from cars built before 1998 were to be reduced by 60%
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NEUTRALIZATION DUE TO SOIL/BEDROCKThe map below shows the potential of soils and bedrock to reduce the acidity of acid rain. Red shaded areas, almost half of Canada's area, are most sensitive to the effects of acid rain
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NEUTRALIZATION DUE TO SOIL/BEDROCKThe map below shows the potential of soils and bedrock to reduce the acidity of acid rain. Red shaded areas, almost half of Canada's area, are most sensitive to the effects of acid rain
Tuesday, March 12, 2013
NEUTRALIZATION DUE TO SOIL/BEDROCKThe map below shows the potential of soils and bedrock to reduce the acidity of acid rain. Red shaded areas, almost half of Canada's area, are most sensitive to the effects of acid rain
Tuesday, March 12, 2013
NEUTRALIZATION DUE TO SOIL/BEDROCKThe map below shows the potential of soils and bedrock to reduce the acidity of acid rain. Red shaded areas, almost half of Canada's area, are most sensitive to the effects of acid rain
Limestone is made up of calcium carbonate (pH 9.4)Tuesday, March 12, 2013
LimingTo neutralize acid rain precipitation, lime (calcium hydroxide - which is a base) is added to lakes.
Calcium Hydroxide + Sulfuric Acid ------ » Calcium Sulfate + Water Ca(OH)2 + H2SO4 ------ » CaSO4 + H2O
***This is not necessary in Alberta because the mountains contain rich deposits of limestone, making the water naturally basic. When the acid rain falls, it is neutralized almost immediately.***
Alkaline minerals (basic) – such as calcium carbonate or calcite - left after glaciers melted, following the Ice Age provide a basic aquatic environment, so that the acid precipitation gets neutralized almost immediately after it enters lakes and water systems.
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Catalytic ConvertorsAn emissions control device installed into vehicles exhaust systems. Using a catalyzed reaction, it
converts toxic byproducts from vehicles into less toxic substances
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Catalyst - a substance that speeds up a reaction without being used up in the reaction
In catalytic converters, the catalyst is what coats the honeycomb structure (typically palladium, rhodium and platinum). The result is that N2, CO2 and H2O are released rather than NOx (nitrous oxides) and hydrocarbons.
High theft of catalytic converters. Why? http://www.globaltvbc.com/catalytic+converter+theft+costing+thousands+in+langley/6442787023/story.html
The 3 main pollutants in car emissions are carbon monoxide, unburned hydrocarbons and oxides of nitrogen. CO and HC are converted to 2 new molecules. This happens through an oxidizing reaction which converts "carbon monoxide (CO) and unburned hydrocarbons (HC)" to "CO2 and water vapor". The last pollutant is converted to 3 new molecules. This happens through a reduction reaction which converts "oxides of nitrogen (NOx)" to "CO2, nitrogen (N2) and water (H2O)".
Catalytic Convertors
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SCRUBBERSA device installed in large factories that use a sorbent that absorbs or
captures the harmful oxides
Dry scrubbers: http://www.youtube.com/watch?v=HE6Y0iEuXMQ
Wet scrubbers: http://www.youtube.com/watch?v=jnfvJ3B2puE
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