This document discusses environmental issues caused by population growth, industrialization, urbanization, and modern lifestyle changes. It identifies four major global problems: global warming, acid rain, depletion of the ozone layer, and provides background information on each of these issues, including their causes and effects. Greenhouse gases from human activities are the main driver of global warming, while acid rain is caused by sulfur dioxide and nitrogen oxide emissions from burning fossil fuels. Ozone depletion is largely due to chlorofluorocarbons released into the atmosphere.

1. PREPARED BY:-
KHUSHBU K. SHAH
ASST. Prof.
S.S.A.S.I.T.
S.S.A.S.I.T
G.T.U
SHREE SWAMI ATMANAND SARASWATI
INSTITUTE OF TECHNOLOGY, SURAT
Environmental studies
(2110007)

2. INTRODUCTION
There are significant changes in the global ecosystem
after the world war. The man made forces disrupting
the global ecosystem can be enlisted as under:-
1. Population explosion
2. Rapid industrialization
3. Urbanization
4. Modern life cycle
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3. All these factor are collectively cause following
global environment problems like:-
1. Global Warming due to Green House Effect
2. Acid Rain
3. Depletion of Ozone layer
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4.  Global warming refers to an unequivocal and continuing rise
in the average temperature of Earth's climate system.
 Since 1971, 90% of the warming has occurred in the
oceans. Despite the oceans' dominant role in energy storage,
the term "global warming" is also used to refer to increases in
average temperature of the air and sea at Earth's surface.
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5.  Since the early 20th century, the global air and sea surface
temperature has increased about 0.8 °C (1.4 °F), with about
two-thirds of the increase occurring since 1980.
 Emissions of greenhouse gases grew 2.2% per year between
2000 and 2010, compared with 1.3% per year from 1970 to
2000.
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6.  Carbon dioxide emissions from fossil fuel burning power plants.
 Carbon dioxide emissions from burning gasoline for
transportation.
 Methane emissions from animals, agriculture such as rice
paddies, and from Arctic sea beds.
 Deforestation, especially tropical forests for wood, pulp, and
farmland.
 Increase in usage of chemical fertilizers on croplands.
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7.  Rise in sea levels worldwide
 More killer storms
 Massive crop failures
 Widespread extinction of species
 Disappearance of coral reefs
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8.  Reduce, Reuse, Recycle
 Use Less Heat and Air Conditioning
 Change a Light Bulb
 Drive Less and Drive Smart
 Buy Energy-Efficient Products
 Use Less Hot Water
 Use the "Off" Switch
 Plant a Tree
 Get a Report Card from Your Utility Company
 Encourage Others to Conserve 8

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The greenhouse effect is when the temperature
rises because the sun’s heat and light is trapped.
 The Earth’s surface thus receives energy from two
sources: the sun & the atmosphere.
 As a result the Earth’s surface is ~33C warmer
than it would be without an atmosphere.

11.  Deforestation
 Cutting down of trees, thus, leads to an increase
in the carbon dioxide level in the atmosphere,
eventually enhancing the greenhouse effect.
 Burning of Fossils
 Greenhouse gases can also be released into the
atmosphere due to the burning of fossil fuels, oil,
coal, and gas.
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12.  Electrical Appliances
 Some processes of the cement manufacturing
industries also act as a cause towards the
greenhouse effect.
 Population Growth
 With the increase in population, the needs and
wants of people increase which consequently
increases deforestation, manufacturing, and
industry processes.
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13.  Carbon Dioxide
 Methane
 Nitrous Oxide
 Chlorofluorocarbons (CFCs)
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PERCENTAGE COMPOSITION OF GREEN
HOUSE GASES
50%
19%
17%
8%
4%
2%
CO2
CH4
CFC
O3
N2O
H2O

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Carbon Dioxide (CO2)
Source: Fossil fuel burning, deforestation
• Last 30 years increase: 30%
• Average atmospheric residence time: 500 year
Methane (CH4)
Source: Rice cultivation, cattle & sheep ranching, decay from
landfills, mining
• Last 30 years increase: 145%
• Average atmospheric residence time: 7-10 years

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Nitrous oxide (N2O)
Source: Industry and agriculture (fertilizers)
• Last 30 years increase: 15%
• Average atmospheric residence time: 140-190 years
Chlorofluorocarbon
 Sources: Air conditioners, refrigerators, evaporation of
industrial solvents, production of plastic foam, etc
Per year increase : 4%
Average residence time in atmosphere : 10-15 years

18.  Recycle your paper, beverage containers, milk jugs,
and tin cans so that they can be used to make new
material and so that we don't waste natural
resources.
 Reuse house hold items.
 Car pool or find another way to travel in order to
preserve the earth's natural resources.
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19.  Acid rain is caused by the burning of fossil fuels.
Burning oil, gas and coal in power stations releases
Sulphur Dioxide (SO2) into the atmosphere. Burning
oil and petrol in motor vehicles puts nitrogen oxides
(NOX) into the atmosphere.
 These gases mix with water droplets in the atmosphere
creating weak solutions of nitric and sulphuric acids.
When precipitation occurs these solutions fall as acid
rain.
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Gases which are at the origin of acid rains
are :
Sulphur dioxyde Carbon dioxyde Nitrogen oxide

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Acid rains appear when :
Sulphur dioxyde Nitrogen oxide
Release sulphuric acid and nitric
acid !
They move up into the air and are released
as acid rains

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In the gas phase sulfur dioxide is oxidized by reaction with
the hydroxyl radical via an intermolecular reaction:
SO2 + OH· → HOSO2·
which is followed by:
HOSO2· + O2 → HO2· + SO3
In the presence of water, sulfur trioxide(SO3) is converted rapidly
to sulfuric acid:
SO3 (g) + H2O (l) → H2SO4 (l)
Nitrogen dioxide reacts with OH to for
NO2 + OH· → HNO3

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a) Acidification of soils:
- Acid rain increases acidity of soil, lakes, streams etc.
- Lower pH can mobilize or leach out important minerals and
release heavy metals in Al3+, Cd, Pb etc. beyond safe limits
- This affects the land & aquatic flora & fauna especially fish
- Thousands of lakes across the world have died i.e. they have lost all
the fish population and much of other organisms
b) Phyto toxicity:
- Directly from excessive concentration of acid and acid forming
gases particularly SO2 & NO2
- Indirectly from Al3+ liberated from soil
- Acid rain, acid fog and acid vapors damage the surfaces of leaves
and needles, reduce a tree’s ability to withstand cold & inhibit plant
germination and reproduction.
- Tree regenerative capability are reduced

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25.  In the area of transportation, NOx needs to be
removed from motor vehicles exhaust.
 Understand acid deposition’s causes and effects.
 Clean up smokestacks and exhaust pipes.
 Use alternative energy sources.
 Restore a damaged environment.
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26.  Ozone depletion describes two distinct but related
phenomena observed since the late 1970s: a steady decline of
about 4% per decade in the total volume of ozone in Earth's
stratosphere (the ozone layer), and a much larger springtime
decrease in stratospheric ozone over Earth's polar regions.
The latter phenomenon is referred to as the ozone hole. In
addition to these well-known stratospheric phenomena, there
are also springtime polar tropospheric ozone depletion
events.
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 1. Chlorofluorocarbons (CFCs) and halons (entirely man made) with
wide application in air conditioning refrigeration, aerosols, foam
blowing and modern fire fighting are the main culprits responsible for
the destruction of ozone in the stratosphere.
 2. In addition, oxides of nitrogen released from the exhausts of large fleet
supersonic aircrafts are also responsible for increasing the rate of ozone
destruction.
 3. CFCs and halons have a long residential period in atmosphere. CFCl2
has a residential time between 60 and 110 years whereas CF2Cl2 has
‘Residence time between 55 and 400 years.
 4. They remain inactive in the troposphere (0-15 Kms) and it takes about
20-40 years for these chemicals to travel to reach stratosphere.

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CFCs Cl
Cl + O3 ClO +O2
ClO + O3 or O 2O2 or O2 + Cl

29.  Skin cancer: Exposure to ultraviolet rays poses an
increased risk of developing several types of skin cancers,
including malignant melanoma, basal and squamous cell
carcinoma.
 Eye damage: Direct exposure to UV radiations can result
in photo keratitis (snow blindness), and cataracts.
 Immune system damage: Effects of UV rays include
impairment of the immune system. Increased exposure to
UV rays weakens the response of the immune system.29

30.  Accelerated aging of skin: Constant exposure to UV
radiation can cause photo allergy, which results in
the outbreak of rash in fair-skinned people.
 Other effects: Ozone chemicals can cause difficulty
in breathing, chest pain, throat irritation, and
hamper lung functioning.
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31.  Limit private vehicle driving
 Use eco-friendly household cleaning products
 Avoid using pesticides
 Developing stringent regulations for rocket
launches
 Banning the use of dangerous nitrous oxide
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