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CONTENTS • Definition• Formation• Causes• Effects• Preventive Measures

DEFINITION OF ACID RAIN• Precipitation that has a pH of less than

that of natural rainwater (which is about 5.6 due to dissolved carbon dioxide).• It is formed when sulphur dioxides and

nitrogen oxides, as gases or fine particles in the atmosphere, combine with water vapour and precipitate as sulphuric acid or nitric acid in rain, snow, or fog.

FORMATION OF ACID RAIN

Acid Rain (pH < 5.6)

NO2 (g) + H2O (l) HNO3 (aq) nitric acid(a strong acid)

Transportation60%

2 SO2 (g) + O2 (g) 2 SO3 (g)

SO3 (g) + H2O (l) H2SO4 (aq) sulfuric acid (a strong acid)

Industrial Sources 68%

Electric Utilities27%

CAUSESNATURAL SOURCES :- Emissions from volcanoes and from

biological processes that occur on the land, in wetlands, and in the oceans contribute acid-producing gases to the atmosphere

Effects of acidic deposits have been detected in glacial ice thousands of years old in remote parts of the globe

• THE PRINCIPAL CAUSE OF ACID RAIN IS FROM HUMAN SOURCES :-

• Burning coal,Oil and natural gas in power stations makes electricity, giving off sulphur dioxide gas.

MSN Encarta

• Burning petrol and oil in vehicle engines gives off nitrogen oxides as gases.

• These gases mix with water vapour and rainwater in the atmosphere producing weak solutions of sulphuric and nitric acids – which fall as acid rain.

EFFECTS• Human Health• Vegetation • Aquatic life• Transport• Sculptures

HUMAN HEALTH• Respiratory problems, asthma, dry

coughs, headaches and throat irritations

• Leeching of toxins from the soil by acid rain can be absorbed by plants and animals. When consumed, these toxins affect humans severely.

• Brain damage, kidney problems, and Alzheimer's disease has been linked to people eating "toxic" animals/plants.

VEGETATION• – Increased acidity in soil– Leeches nutrients from

soil, slowing plant growth– Leeches toxins from soil,

poisoning plants–Creates brown spots in

leaves of trees, impeding photosynthesis–Allows organisms to infect

through broken leaves

• Lakes are also damaged by acid rain. Fish die off, and that removes the main source of food for birds. • Acid rain can even kill

fish before they are born when the eggs are laid and come into contact .• Also, birds can die from

eating "toxic" fish and insects.

AQUATIC LIFE

TRANSPORT Currently, both the

railway industry and the aeroplane industry are having to spend a lot of money to repair the corrosive damage done by acid rain.

• Also, bridges have collapsed in the past due to acid rain corrosion.

SCULPTURES, BUILDINGS• • Acid rain dissolves

the stonework and mortar of buildings (especially those made out of sandstone or limestone).

• It reacts with the minerals in the stone to form a powdery substance that can be washed away by rain.

What are the solutions to acid

rain?

Use Energy Sources that Don’t Produce Nitrogen or Sulfur Oxides

Lifestyle Decisions

conserve electricity

drive less

• Liming– Powdered

limestone/limewater added to water and soil to neutralize acid

– Used extensively in Norway and Sweden

– Expensive, short-term remedy

Legislation

Canadian PM Brian Mulrooney & U.S. President George Bushsigned the Acid Rain Accord in 1991, committing both of theircountries to reduce acid rain emissions.