THE ACID RAIN

Environmental Engineer Group

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!

DAMAGES THE ENVIRONMENT

pH

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)

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

Nitrogen Oxide ( NOx )

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

the NOx emissions amount( 1998 )

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

The amount of wet sulphate deposition (kg/ha/yr)

http://www.ec.gc.ca/acidrain/acidfact.html

Environmental Engineer

History of Acid Rain

Major problem area

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

Major problem area

Major problem area

• Canada

• British Columbia

• United States

• Central Europe

• Asia

Reference

• Virtual Globe http://www.virtualglobe.org/en/info/env/03/acid06.html

• The acid rain report http://www.angelfire.com/ks3/acidrainreport/history2.html

• Living Landscapes http://royal.okanagan.bc.ca/mpidwirn/atmosphereandclimate/acidprecip.html#a