Alexandria University

Faculty of engineering
Mechanical engineering department
4Th year

Air Pollution

Name: Osama Mohamed Ali Hussein Haraz

Dr. Mervat A. Abdel_Kawi

1. Air pollution
1.1. Introduction

1.2. History

1.3. Sources of Air Pollution

1.4. Effects on Health and the Environment

1.5. Solutions to Air Pollution

2. Global Warming
2.1. What Is Global Warming?

2.1.1. Greenhouse effect

2.1.2. Aren't temperature changes natural?

2.1.3. Why is this concern?

2.2. Causes of Global Warming

2.2.1. What Causes Global Warming?

2.3. Effects of Global Warming

2.4. Global Warming Solutions

2.4.1. What Can We Do?

2.4.2. Is this possible?

1.1. Introduction
Smog hanging over cities is the most familiar and obvious form of air pollution. But there
are different kinds of pollution—some visible, some invisible—that contribute to global
warming. Generally any substance that people introduce into the atmosphere that has
damaging effects on living things and the environment is considered air pollution.

Carbon dioxide, a greenhouse gas, is the main pollutant that is warming Earth. Though
living things emit carbon dioxide when they breathe, carbon dioxide is widely considered
to be a pollutant when associated with cars, planes, power plants, and other human
activities that involve the burning of fossil fuels such as gasoline and natural gas. In the
past 150 years, such activities have pumped enough carbon dioxide into the atmosphere
to raise its levels higher than they have been for hundreds of thousands of years.

Other greenhouse gases include methane—which comes from such sources as swamps
and gas emitted by livestock—and chlorofluorocarbons (CFCs), which were used in
refrigerants and aerosol propellants until they were banned because of their
deteriorating effect on Earth's ozone layer.

Another pollutant associated with climate change is sulfur dioxide, a component of smog.
Sulfur dioxide and closely related chemicals are known primarily as a cause of acid rain.
But they also reflect light when released in the atmosphere, which keeps sunlight out and
causes Earth to cool. Volcanic eruptions can spew massive amounts of sulfur dioxide into
the atmosphere, sometimes causing cooling that lasts for years. In fact, volcanoes used to
be the main source of atmospheric sulfur dioxide; today people are.

1.2. History
Air pollution existed in prehistory in the form of  volcanic eruptions, wildfires and
duststorms and with their associated sulfur dioxide, carbon monoxide and particulate
matter. In the Middle Ages coal burning was outlawed in London while Parliament was in
session. However, the phenomenon of air pollution accelerated dramatically due to the
increase of emissions since the Industrial Revolution.

1.3. Sources of Air Pollution

The combustion of gasoline and other hydrocarbon fuels in automobiles, trucks, and jet
airplanes produces several primary pollutants: nitrogen oxides, gaseous hydrocarbons,
and carbon monoxide, as well as large quantities of particulates, chiefly lead. In the
presence of sunlight, nitrogen oxides combine with hydrocarbons to form a secondary
class of pollutants, the photochemical oxidants, among them ozone and the eye-stinging
peroxyacetylnitrate (PAN). Nitrogen oxides also react with oxygen in the air to form
nitrogen dioxide, a foul-smelling brown gas. In urban areas like Los Angeles where
transportation is the main cause of air pollution, nitrogen dioxide tints the air, blending
with other contaminants and the atmospheric water vapor to produce brown smog.
Although the use of catalytic converters has reduced smog-producing compounds in
motor vehicle exhaust emissions, recent studies have shown that in so doing the
converters produce nitrous oxide, which contributes substantially to global warming.
2- Factories

In cities, air may be severely polluted not only by transportation but also by the burning
of fossil fuels (oil and coal) in generating stations, factories, office buildings, and homes
and by the incineration of garbage. The massive combustion produces tons of ash, soot,
and other particulates responsible for the gray smog of cities like New York and Chicago,
along with enormous quantities of sulfur oxides (which also may be result from burning
coal and oil). These oxides rust iron, damage building stone, decompose nylon, tarnish
silver, and kill plants. Air pollution from cities also affects rural areas for many miles
downwind.

3-Petroleum

Every industrial process exhibits its own pattern of air pollution. Petroleum refineries are
responsible for extensive hydrocarbon and particulate pollution. Iron and steel mills,
metal smelters, pulp and paper mills, chemical plants, cement and asphalt plants—all
discharge vast amounts of various particulates. Uninsulated high-voltage power lines
ionize the adjacent air, forming ozone and other hazardous pollutants. Airborne
pollutants from other sources include insecticides, herbicides, radioactive fallout, and
dust from fertilizers, mining operations, and livestock feedlots.

4- Volcanoes

Volcanoes emit chemicals into the air with both explosive eruptions and venting. Holt
molten magma beneath the Earth's surface traps gases such as sulfur and chlorine within
the liquid rock. When eruptions occur, the magma releases the gas into the atmosphere
in the form of tiny acid particles. Volcanic gases can climb thousands of miles into the air.
The weather carries the acidic air mass around the globe. Rain brings the particles closer
to the ground, releasing particles into our water supply.
5- Wildfires

Wildfires, like the ones often seen in California, take a toll on pollution levels of the area.
As plants and trees burn, ash and chemicals release into the air. This cloud of noxious
gases doesn't dissipate quickly. Wildfire smoke can cause a cloud filled with fine particles
containing over 1,000 compounds, according to California Breathing, a resident education
branch of the California Department of Public Health. People living near wildfires can
experience health problems. These include breathing problems and eye irritation as well
as serious health concerns for those with asthma and heart conditions. Wildfires contain
elevated levels of carbon monoxide, a deadly air pollutant that can cause death.

6- Pesticides

Pesticides used to kill indoor and outdoor pests, insecticides used to kill insects and
herbicides use to kill weeds all cause air pollution.

7- Power Lines

Some power lines are not insulated and are high voltage. This creates air pollution.

8- Radioactive Fallout

Radioactive fallout causes air pollution from the nuclear energy dispersed, which is a
dust.

9- Fertilizer Dust

Dust from fertilizers used to help plants grow causes air pollution.

10- Indoor Air Pollution

Sick building syndrome (SBS) is the term used when there is indoor air pollution. This
happens when there is not enough ventilation to disburse the toxic fumes from new
carpet, paint and/or cleaning chemicals that are used indoors. Mold can also cause SBS.

11- Mining Operations

Mining causes air pollution by releasing a variety of particles.

12- Mills and Plants

Mills and plants, include paper mills, chemical plants, iron mills, steel mills, cement plants
and asphalt plants, release emissions into the air causing air pollution.
1.4. Effects on Health and the Environment
Like photochemical pollutants, sulfur oxides contribute to the incidence of respiratory
diseases. Acid rain, a form of precipitation that contains high levels of sulfuric or nitric
acids, can contaminate drinking water and vegetation, damage aquatic life, and erode
buildings. When a weather condition known as a temperature inversion prevents
dispersal of smog, inhabitants of the area, especially children and the elderly and
chronically ill, are warned to stay indoors and avoid physical stress. The dramatic and
debilitating effects of severe air pollution episodes in cities throughout the world—such
as the London smog of 1952 that resulted in 4,000 deaths—have alerted governments to
the necessity for crisis procedures. Even everyday levels of air pollution may insidiously
affect health and behavior. Indoor air pollution is a problem in developed countries,
where efficient insulation keeps pollutants inside the structure. In less developed nations,
the lack of running water and indoor sanitation can encourage respiratory infections.
Carbon monoxide, for example, by driving oxygen out of the bloodstream, causes apathy,
fatigue, headache, disorientation, and decreased muscular coordination and visual acuity.

Air pollution may possibly harm populations in ways so subtle or slow that they have not
yet been detected. For that reason research is now under way to assess the long-term
effects of chronic exposure to low levels of air pollution—what most people experience—
as well as to determine how air pollutants interact with one another in the body and with
physical factors such as nutrition, stress, alcohol, cigarette smoking, and common
medicines. Another subject of investigation is the relation of air pollution to cancer, birth
defects, and genetic mutations.

A recently discovered result of air pollution are seasonal “holes” in the ozone layer in the
atmosphere above Antarctica and the Arctic, coupled with growing evidence of global
ozone depletion. This can increase the amount of ultraviolet radiation reaching the earth,
where it damages crops and plants and can lead to skin cancer and cataracts. This
depletion has been caused largely by the emission of chlorofluorocarbons (CFCs) from
refrigerators, air conditioners, and aerosols.

1.5. Solutions to Air Pollution

To combat pollution in the United States, the Clean Air Act Amendments of 1970 gave the
Environmental Protection Agency (EPA) the authority to establish and enforce air
pollution standards and to set emission standards for new factories and extremely
hazardous industrial pollutants. The states were required to meet “ambient air quality
standards” by regulating the emissions of various pollutants from existing stationary
sources, such as power plants and incinerators, in part by the installation of smokestack
scrubbers, electrostatic precipitators, and other filters. Auto manufacturers were
mandated to install exhaust controls or develop less polluting engines. The Clean Air Act,
as amended in 1977, authorized the EPA to impose stricter pollution standards and
higher penalties for failure to comply with air quality standards.

In 1990 when the act was reauthorized it required most cities to meet existing smog
reduction regulations by the year 2005. The 1990 amendments also expanded the scope
and strength of the regulations for controlling industrial pollution. The result has been
limited progress in reducing the quantities of sulfur dioxide, carbon monoxide, nitrogen
oxide, ozone, particulate matter, and lead in the air. The EPA also regulated hazardous air
pollutants, which in 1992 included mercury, beryllium, asbestos, vinylchloride, benzene,
radioactive substances, and inorganic arsenic.

The most satisfactory long-term solutions to air pollution may well be the elimination of
fossil fuels and the ultimate replacement of the internal-combustion engine. To these
ends efforts have begun in the United States, Japan, and Europe to develop alternative
energy sources, as well as different kinds of transportation engines, perhaps powered by
electricity or steam. A system of pollution allowances based on trading emission rights
has been established in the United States in an attempt to use the free market to reward
pollution reductions, and the international sale of surplus emission rights is permitted
under the Kyoto Protocol (see below). Other proposed solutions include raising electricity
and gasoline rates to better reflect environmental costs and to discourage waste and
inefficiency, and mechanical controls on coal-fired utility plants.

In 1992, 150 nations signed a treaty on global warming at the UN-sponsored summit on
the environment in Rio de Janeiro. A UN Conference on Climate Change, held in Kyoto,
Japan, in 1997, produced an international agreement to combat global warming by
sharply reducing emissions of industrial gases. Although the United States abandoned the
treaty in 2001, saying it was counter to U.S. interests, most other nations agreed that
year on the details necessary to make the protocol a binding international treaty, and the
necessary ratifications brought the treaty into force in 2005.

Industrialized countries have worked to reduce levels of sulfur dioxide, smog, and smoke
in order to improve people's health. But a result, not predicted until recently, is that the
lower sulfur dioxide levels may actually make global warming worse. Just as sulfur dioxide
from volcanoes can cool the planet by blocking sunlight, cutting the amount of the
compound in the atmosphere lets more sunlight through, warming the Earth. This effect
is exaggerated when elevated levels of other greenhouse gases in the atmosphere trap
the additional heat.

Most people agree that to curb global warming, a variety of measures need to be taken.
On a personal level, driving and flying less, recycling, and conservation reduces a person’s
"carbon footprint"—the amount of carbon dioxide a person is responsible for putting into
the atmosphere.

On a larger scale, governments are taking measures to limit emissions of carbon dioxide
and other greenhouse gases. One way is through the Kyoto Protocol, an agreement
between countries that they will cut back on carbon dioxide emissions. Another method
is to put taxes on carbon emissions or higher taxes on gasoline, so that people and
companies will have greater incentives to conserve energy and pollute less.
 2. Global Warming

2.1. What Is Global Warming?

Glaciers are melting, sea levels are rising, cloud forests are drying, and wildlife is
scrambling to keep pace. It's becoming clear that humans have caused most of the past
century's warming by releasing heat-trapping gases as we power our modern lives. Called
greenhouse gases, their levels are higher now than in the last 650,000 years.

We call the result global warming, but it is causing a set of changes to the Earth's climate,
or long-term weather patterns, that varies from place to place. As the Earth spins each
day, the new heat swirls with it, picking up moisture over the oceans, rising here, settling
there. It's changing the rhythms of climate that all living things have come to rely upon.

2.1.1. Greenhouse effect

The "greenhouse effect" is the warming that happens when certain gases in Earth's
atmosphere trap heat. These gases let in light but keep heat from escaping, like the glass
walls of a greenhouse.

First, sunlight shines onto the Earth's surface, where it is absorbed and then radiates back
into the atmosphere as heat. In the atmosphere, “greenhouse” gases trap some of this
heat, and the rest escapes into space. The more greenhouse gases are in the atmosphere,
the more heat gets trapped.
Levels of greenhouse gases (GHGs) have gone up and down over the Earth's history, but
they have been fairly constant for the past few thousand years. Global average
temperatures have stayed fairly constant over that time as well, until recently. Through
the burning of fossil fuels and other GHG emissions, humans are enhancing the
greenhouse effect and warming Earth.

Scientists often use the term "climate change" instead of global warming. This is because
as the Earth's average temperature climbs, winds and ocean currents move heat around
the globe in ways that can cool some areas, warm others, and change the amount of rain
and snow falling. As a result, the climate changes differently in different areas.
2.1.2. Aren't temperature changes natural?

The average global temperature and concentrations of carbon dioxide (one of the major
greenhouse gases) have fluctuated on a cycle of hundreds of thousands of years as the
Earth's position relative to the sun has varied. As a result, ice ages have come and gone.

However, for thousands of years now, emissions of GHGs to the atmosphere have been
balanced out by GHGs that are naturally absorbed.  As a result, GHG concentrations and
temperature have been fairly stable. This stability has allowed human civilization to
develop within a consistent climate.

Occasionally, other factors briefly influence global temperatures.  Volcanic eruptions, for
example, emit particles that temporarily cool the Earth's surface.  But these have no
lasting effect beyond a few years. Other cycles, such as El Niño, also work on fairly short
and predictable cycles.

Now, humans have increased the amount of carbon dioxide in the atmosphere by more
than a third since the industrial revolution. Changes this large have historically taken
thousands of years, but are now happening over the course of decades.

2.1.3. Why is this concern?

The rapid rise in greenhouse gases is a problem because it is changing the climate faster
than some living things may be able to adapt. Also, a new and more unpredictable
climate poses unique challenges to all life.

Historically, Earth's climate has regularly shifted back and forth between temperatures
like those we see today and temperatures cold enough that large sheets of ice covered
much of North America and Europe. The difference between average global temperatures
today and during those ice ages is only about 5 degrees Celsius (9 degrees Fahrenheit),
and these swings happen slowly, over hundreds of thousands of years.

Now, with concentrations of greenhouse gases rising, Earth's remaining ice sheets (such
as Greenland and Antarctica) are starting to melt too. The extra water could potentially
raise sea levels significantly.

As the mercury rises, the climate can change in unexpected ways. In addition to sea levels
rising, weather can become more extreme. This means more intense major storms, more
rain followed by longer and drier droughts (a challenge for growing crops), changes in the
ranges in which plants and animals can live, and loss of water supplies that have
historically come from glaciers.

Scientists are already seeing some of these changes occurring more quickly than they had
expected. According to the Intergovernmental Panel on Climate Change, eleven of the
twelve hottest years since thermometer readings became available occurred between
1995 and 2006.

2.2. Causes of Global Warming

2.2.1. What Causes Global Warming?

Scientists have spent decades figuring out what is causing global warming. They've looked
at the natural cycles and events that are known to influence climate. But the amount and
pattern of warming that's been measured can't be explained by these factors alone. The
only way to explain the pattern is to include the effect of greenhouse gases (GHGs)
emitted by humans.

To bring all this information together, the United Nations formed a group of scientists
called the International Panel on Climate Change, or IPCC. The IPCC meets every few
years to review the latest scientific findings and write a report summarizing all that is
known about global warming. Each report represents a consensus, or agreement, among
hundreds of leading scientists.

One of the first things scientists learned is that there are several greenhouse gases
responsible for warming, and humans emit them in a variety of ways. Most come from
the combustion of fossil fuels in cars, factories and electricity production. The gas
responsible for the most warming is carbon dioxide, also called CO2. Other contributors
include methane released from landfills and agriculture (especially from the digestive
systems of grazing animals), nitrous oxide from fertilizers, gases used for refrigeration
and industrial processes, and the loss of forests that would otherwise store CO2.

Different greenhouse gases have very different heat-trapping abilities. Some of them can
even trap more heat than CO2. A molecule of methane produces more than 20 times the
warming of a molecule of CO2. Nitrous oxide is 300 times more powerful than CO2. Other
gases, such as chlorofluorocarbons (which have been banned in much of the world
because they also degrade the ozone layer), have heat-trapping potential thousands of
times greater than CO2. But because their concentrations are much lower than CO2,
none of these gases adds as much warmth to the atmosphere as CO2 does.

In order to understand the effects of all the gases together, scientists tend to talk about
all greenhouse gases in terms of the equivalent amount of CO2. Since 1990, yearly
emissions have gone up by about 6 billion metric tons of "carbon dioxide equivalent"
worldwide, more than a 20% increase.

2.3. Effects of Global Warming

The planet is warming, from North Pole to South Pole, and everywhere in between.
Globally, the mercury is already up more than 1 degree Fahrenheit (0.8 degree Celsius),
and even more in sensitive polar regions. And the effects of rising temperatures aren’t
waiting for some far-flung future. They’re happening right now. Signs are appearing all
over, and some of them are surprising. The heat is not only melting glaciers and sea ice,
it’s also shifting precipitation patterns and setting animals on the move

.
Some impacts from increasing temperatures are already happening.

 Ice is melting worldwide, especially at the Earth’s poles. This includes mountain
glaciers, ice sheets covering West Antarctica and Greenland, and Arctic sea ice.
 Researcher Bill Fraser has tracked the decline of the Adélie penguins on Antarctica,
where their numbers have fallen from 32,000 breeding pairs to 11,000 in 30 years.
 Sea level rise became faster over the last century.
 Some butterflies, foxes, and alpine plants have moved farther north or to higher,
cooler areas.
 Precipitation (rain and snowfall) has increased across the globe, on average.
 Spruce bark beetles have boomed in Alaska thanks to 20 years of warm summers.
The insects have chewed up 4 million acres of spruce trees.

Other effects could happen later this century, if warming continues.

 Sea levels are expected to rise between 7 and 23 inches (18 and 59 centimeters) by
the end of the century, and continued melting at the poles could add between 4
and 8 inches (10 to 20 centimeters).
 Hurricanes and other storms are likely to become stronger.
 Species that depend on one another may become out of sync. For example, plants
could bloom earlier than their pollinating insects become active.
 Floods and droughts will become more common. Rainfall in Ethiopia, where
droughts are already common, could decline by 10 percent over the next 50 years.
 Less fresh water will be available. If the Quelccaya ice cap in Peru continues to melt
at its current rate, it will be gone by 2100, leaving thousands of people who rely on
it for drinking water and electricity without a source of either.
 Some diseases will spread, such as malaria carried by mosquitoes.
 Ecosystems will change—some species will move farther north or become more
successful; others won’t be able to move and could become extinct. Wildlife
research scientist Martyn Obbard has found that since the mid-1980s, with less ice
on which to live and fish for food, polar bears have gotten considerably skinnier. 
Polar bear biologist Ian Stirling has found a similar pattern in Hudson Bay.  He fears
that if sea ice disappears, the polar bears will as well.
2.4. Global Warming Solutions

2.4.1. What Can We Do?

The evidence that humans are causing global warming is strong, but the question of what
to do about it remains controversial. Economics, sociology, and politics are all important
factors in planning for the future.

Even if we stopped emitting greenhouse gases (GHGs) today, the Earth would still warm
by another degree Fahrenheit or so. But what we do from today forward makes a big
difference.  Depending on our choices, scientists predict that the Earth could eventually
warm by as little as 2.5 degrees or as much as 10 degrees Fahrenheit.

A commonly cited goal is to stabilize GHG concentrations around 450-550 parts per
million (ppm), or about twice pre-industrial levels. This is the point at which many believe
the most damaging impacts of climate change can be avoided.  Current concentrations
are about 380 ppm, which means there isn't much time to lose.  According to the IPCC,
we'd have to reduce GHG emissions by 50% to 80% of what they're on track to be in the
next century to reach this level.
2.4.2. Is this possible?

Many people and governments are already working hard to cut greenhouse gases, and
everyone can help.

Researchers Stephen Pacala and Robert Socolow at Princeton University have suggested
one approach that they call "stabilization wedges." This means reducing GHG emissions
from a variety of sources with technologies available in the next few decades, rather than
relying on an enormous change in a single area.  They suggest 7 wedges that could each
reduce emissions, and all of them together could hold emissions at approximately current
levels for the next 50 years, putting us on a potential path to stabilize around 500 ppm.

There are many possible wedges, including improvements to energy efficiency and
vehicle fuel economy (so less energy has to be produced), and increases in wind and solar
power, hydrogen produced from renewable sources, biofuels (produced from crops),
natural gas, and nuclear power.  There is also the potential to capture the carbon dioxide
emitted from fossil fuels and store it underground—a process called "carbon
sequestration."

In addition to reducing the gases we emit to the atmosphere, we can also increase the
amount of gases we take out of the atmosphere.  Plants and trees absorb CO2 as they
grow, "sequestering" carbon naturally.  Increasing forestlands and making changes to the
way we farm could increase the amount of carbon we're storing.

Some of these technologies have drawbacks, and different communities will make
different decisions about how to power their lives, but the good news is that there are a
variety of options to put us on a path toward a stable climate.
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http://environment.nationalgeographic.com/environment/global-warming/gw-causes

http://environment.nationalgeographic.com/environment/global-warming/gw-effects/

http://environment.nationalgeographic.com/environment/global-warming/gw-overview

http://environment.nationalgeographic.com/environment/global-warming/gw-solutions

http://www.ehow.com/about_5371911_causes-air-pollution-ways-improve.html