The document discusses acid rain, defined as precipitation with a pH lower than natural rainwater, formed primarily from sulfur dioxide and nitrogen oxides released from industrial activities. It details the causes, measurement methods, effects on the environment, and human health, highlighting its destructive impact on forests, aquatic life, and buildings. The document also proposes solutions such as using cleaner fuels and renewable energy to mitigate acid rain.

1. Acid rain
By : Charu Jaiswal

2. CONTENTS
1 :WHAT IS ACID RAIN ?
2 :DEFINITION
3 :HOW DO WE MEASURE THE LEVEL OF ACID IN THE PRECIPITATION?
4 :CAUSES OF ACID RAIN
5 :CHEMICAL EQUATIONS
6 :FORMATION OF ACID RAIN
7 :AFFECTED AREAS
8 :EFFECTS OF ACID RAIN ON TRESS , AQUATIC LIFE, BUILDINGS , VEGETATION AND HUMAN HEALTH
9 :THE PROBLEM !
10 :SOLUTIONS

3. WHAT IS ACID RAIN ?
Acid Rain is the 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.

4. DEFINITION
Dictionary.com
Precipitation, as rain, snow, or
sleet, containing relatively high
concentrations of acid-forming
chemicals, as the pollutants
from coal smoke, chemical
manufacturing, and smelting,
that have been released into the
atmosphere and combined with
water vapour: harmful to the
environment.
Britannica.com
Any precipitation, including snow,
that contains a heavy concentration
of sulphuric and nitric acids. This form
of pollution is a serious
environmental problem in the large
urban and industrial areas of North
America, Europe, and Asia.
Automobiles, certain industrial
operations, and electric power plants
that burn fossil fuels emit the gases
sulphur dioxide and nitrogen oxide
into the atmosphere, where they
combine with water vapour in clouds
to form sulphuric and nitric acids.
US FED GOVT
"Acid rain" is a broad term referring
to a mixture of wet and dry
deposition (deposited material) from
the atmosphere containing higher
than normal amounts of nitric and
sulphuric acids. The precursors, or
chemical forerunners, of acid rain
formation result from both natural
sources, such as volcanoes and
decaying vegetation, and man-made
sources, primarily emissions of
sulphur dioxide and nitrogen oxides
resulting from fossil fuel combustion

5. HOW DO WE MEASURE THE LEVEL OF
ACID IN THE PRECIPITATION?
pH tests determine how much hydrogen ions
in a litter of fluid, by using the pH scale we can
measure acidity or alkalinity. We do the same
pH tests in our pools and hot tubs. The scale
runs from 0 to 14 with water having a neutral
pH of 7. The greater the concentration of
hydrogen ions the lower the pH number, the
more acidic based the water is; the lower the
concentration of hydrogen ions and the higher
the pH number, the more alkaline based the
water is. So a pH greater than 7 tells us that it
is an alkaline substance while a pH less than 7
indicates an acidic substance. One unit of pH
change equals a 10 time change in the of
concentration of hydrogen ions. Normal rain
and snow measure about pH 5.60.

6. CAUSES OF ACID RAIN
NATURAL 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
HUMAN SOURCES: The principal cause of acid rain is from
human sources Industrial factories, power-generating plants
and vehicles Sulphur dioxide and oxides of nitrogen are
released during the fuel burning process (i.e. combustion )

7. CHEMICAL EQUATIONS
Both sulphuric acid and nitric acid are soluble in water and are the major acids present in
acid rain. As this forms and falls onto the Earth's surface, these strong acids are also
brought to the surface causing harmful effects on the built and the natural environment.
Sulfur dioxide reacts with water to form sulfurous acid.
SO2(g) + H2O(l) -> H2SO3(aq)
Substances in the upper atmosphere then catalyze the reaction between sulfurous acid
and oxygen to form sulfuric acid.
2H2SO3(aq) + O2(g) -> 2H2SO4(aq)
Similarly, nitrogen dioxide reacts with water to form a mixture of nitric acid and nitrous
acid.
2NO2(g) + H2O(l) -> HNO3(aq) + HNO2(aq)
Substances in the atmosphere then catalyze the reaction between nitrous acid and oxygen
causing the formation of more nitric acid.
2HNO2(aq) + O2(g) -> 2HNO3(aq)

8. FORMATION OF ACID RAIN
Formation of Acid Rain When water vapour condenses, or as the rain falls, they dissolve in the water to form
sulphuric acid (H2SO4) and nitric acid (HNO3). While the air in cleaned of the pollutants in this way, it also
causes precipitation to become acidic, forming acid rain

9. AFFECTED AREAS
Canada: Acid rain is a problem in Canada . Water and soil systems
lack natural alkalinity such as lime base Cannot neutralize acid .
Industrial acid rain is a substantial problem in China, Eastern
Europe and Russia and areas down-wind from them.
Acid rain from power plants in the Midwest United States has also
harmed the forests of upstate New York and New England.
This shows that the effects of acid rain can spread over a large
area, far from the source of the pollution

10. EFFECTS OF ACID RAIN
Acid rain is an extremely destructive form of
pollution, and the environment suffers from its
effects. Forests, trees, lakes, animals, and plants
suffer from acid rain.
Trees : The needles and leaves of the trees turn
brown and fall off. Trees can also suffer from
stunted growth; and have damaged bark and
leaves, which makes them vulnerable to
weather, disease, and insects. All of this happens
partly because of direct contact between trees
and acid rain, but it also happens when trees
absorb soil that has come into contact with acid
rain. The soil poisons the tree with toxic
substances that the rain has deposited into it.

11. EFFECTS ON AQUATIC LIFE
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 with the acid.
Fish usually die only when the acid level of a
lake is high; when the acid level is lower,
they can become sick, suffer stunted growth,
or lose their ability to reproduce.
Also, birds can die from eating "toxic" fish
and insects.

12. EFFECTS ON 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.
Accelerates weathering in metal
and stones structures . Eg.
Parthenon in Athens , Greece
and Taj Mahal in Agra , India .

13. HARMFUL TO 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.

14. AFFECTS 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.
Research carried out in
North America in 1982,
revealed that sulphur
pollution killed 51,000
people and about
200,000 people become
ill as a result of the
pollution.

15. THE PROBLEM!
Acid rain can travel long distances.
Often it doesn’t fall where the gas is produced. High
chimneys disperse (spread) the gases and winds blow
them great distances before they dissolve and fall to
Earth as rain.
Eg. gases produced in England and Western Europe can
result in acid rain in Scotland and Scandinavia.
People probably couldn't live without electricity!
Therefore coal will continue to be burnt. Also, electricity
and energy are constantly being overused.

16. SOLUTIONS
Use cleaner fuels ,Use Coal that contains less sulphur ."Washing" the coal to reduce sulphur
content .
Sulphur dioxide can be removed from power stations chimneys but this process is expensive.
Remove oxides of sulphur and oxides of nitrogen before releasing Flue gas desulphurization
Use renewable energy like wind power, solar panels, tidal power, HEP schemes and geothermal
energy.
Fit catalytic converters to vehicle exhausts which remove the nitrogen oxides.
Limit the number of vehicles on the roads and increase public transport.
Reducing the effects of Acid Rain Liming Powdered limestone/limewater added to water and soil
to neutralize acid Used extensively in Norway and Sweden Expensive, short-term remedy

17. THANK YOU !