the acid rain environmental engineer group. introduction
TRANSCRIPT
INTRODUCTION
ACID DEPOSITION
1. Dry deposition
- Acidic gases and particles
2. Wet deposition
- Acidic rain, fog and snow
THE ACID RAIN
What is Acid rain?
- Acid rain is rain, snow or fog that is polluted by acid in the atmosphere and damages the environment.
ACID RAIN DROP
Acid Rain
(Acid Precipitation)
Any precipitation carrying dissolved acids from natural or man made causes.Examples; a. CO2 dissolves in H2O---------> Creates carbonic acid (H2CO3)b. Sulfur dioxide (from internal combustion) mixes with H2O ---------> Sulfuric Acid (H2SO4)c. Nitrogen oxides (from internal combustion) mixes with H2O ---------> Nitric Acid (HNO3)
*Acid precipitation may have a pH as low as 3. Very Acidic!
*Acids in the air may be carried thousands of miles from their source, polluting soil & water in pristine areas!
pH
• a number on a scale of 0 to 14 which shows how acid or alkaline a substance is
• Measure the amount of acid in a liquid – like water
The Water Molecule
• Formula of water = H20 H = hydrogen 2 = 2 hydrogen atoms O = oxygen.
http://www.miamisci.org/ph
•Pour acid into water give up H+ to water = acid
Pour base into water give up OH- to water = base
http://www.miamisci.org/ph
Ph 14.0 13.0 12.4 11.0 10.5 8.3 7.4
Substance
Sodium Hydroxide
Lye Lime (Calcium hydroxide)
Ammonia Milk of Magnesia
Baking Soda
Human Blood
Base
7.0 6.6 4.5 4.0 3.0 2.2 2.0 1.0 0
PureWater
Milk Tomato Wine &
Bee
Apple Vinegar
Lemon Juice
Battery Acid
Hydrochloric
Acid
Neutral
Acid
http://www.miamisci.org/ph
Ph 14.0 13.0 12.4 11.0 10.5 8.3 7.4
Substance
Sodium Hydroxide
Lye Lime (Calcium hydroxide)
Ammonia Milk of Magnesia
Baking Soda
Human Blood
Base
7.0 6.6 4.5 4.0 3.0 2.2 2.0 1.0 0
PureWater
Milk Tomato Wine &
Bee
Apple Vinegar
Lemon Juice
Battery Acid
Hydrochloric
Acid
Neutral
Acid
http://www.miamisci.org/ph
• Normal rain = slightly acidic = 5.5 (carbon dioxide dissolves into it)
• In 2000, rain pH = 4.3 (in the US)
http://www.epa.gov/airmarkets/acidrain
Sulphur dioxide (SO2)• cause by natural phenomena and
anthropogenic activities • is soluble in water • can be oxidised within airborne wate
r droplets • producing sulphuric acid
Comes From
• combustion of fossil fuels • oxidation of organic material in soils • volcanic eruptions • biomass burning
http://www.temis.nl/products/so2.html
Reaction
• Sulphur dioxide is an acidic gas • Easily be made by adding water
SO2 (g) SO2 (aq) SO2 (aq) + H2O (l) H2SO3 (aq) weakly dibasic acid
http://www.chm.bris.ac.uk/motm/so2/so2h.htm
The Combustion Of Fuels
• Residential
• cars
• commercial furnaces
• Industrial
• electrical-utility boilers
• Engines
• other equipment
Canada’s largest contributor of NOx ( 1998 )
11%
7% 3%
26%
53%
Transportation
IndustrialSources
Electric Utilities
Other
Fuel Combustion
http://www.ec.gc.ca/acidrain/acidfact.html
America’s largest contributor of NOx ( 1998 )
25%
12%
5% 5%
53%
Transprotation
Electric Utilities
IndustrialSources
Fuel Combuston
Other
http://www.ec.gc.ca/acidrain/acidfact.html
Critical Load & Target Load
• Critical Load:
a measure of how much pollution an environment can tolerate
• Target Load:
the amount of pollution that is considered achievable and politically acceptable
History of Acid Rain
1. Originated during the 1730's
2. Discovered in the 1950's
3. Started being noticed in the 1960's
4. 1984 - Germany
5. 1988 - United Nations
6. 2000