3. ATMOSPHERE.
The Earth's atmosphere, or air, is made of
gases like nitrogen, carbon dioxide and
oxygen. Every time we take a breath, we
use the oxygen part of air. When we breathe
out, carbon dioxide goes into the
air. Sometimes particles of water, dust and
bits of smoke can be in the air too.
4. GASES
oxygen :-(O2), (20.95% of volume) almost entirely of biological
origin, produced by auto-Trophic organisms (plants), thanks to the
function of the chlorophyll in the photosynthesis;
carbon dioxide :-(CO2) (in varying proportions) of natural and
anthropogenic origin (i.e. generated by man’s activities: for
instance combustion processes);
water :-(H2O), (in varying proportions) that may be present in the
atmosphere as steam or in a liquid or solid state;
nitrogen :-(N2), equal to 78% of the volume and argon (A) equal
to 0.93% of the volume, both inert gases;
other gases :-such as neon, krypton, xenon, hydrogen and
others that taken together make up just 0.01% of the volume of
the atmosphere. Solid and liquid particles
(dust, spores, pollen, etc.) are present in limited amounts and
their size, physical characteristics and chemical properties are
extremely variable.
5. The atmosphere is an essential component for life on Earth, since
it contains the oxygen that living organisms need to breathe. In
addition, it filters out the harmful solar radiations, reflecting them
and preventing them from reaching the soil, and allows the Earth’s
surface to maintain the right temperature for plants and animals to
live. The atmosphere is also the place where the main weather
phenomena (wind, rain, snow, etc.), that compose the climate,
occur.
6. AIR QUALITY
"Bad air quality" and "Air quality" redirect here. For the
obsolete medical theory, see Bad air. For the measure of how
polluted the air is , see Air quality index.
Not to be confused with Qualities of air.
Air pollution from a World War II wartime production plant
Air pollution is the introduction of
chemicals, particulates, biological materials, or other harmful
materials into the Earth's atmosphere, possibly causing
disease, death to humans, damage to other living organisms
such as food crops, or the natural or built environment.
The atmosphere is a complex natural gaseous system that is
essential to support life on planet Earth. Stratospheric ozone
depletion due to air pollution has long been recognized as a
threat to human health as well as to the Earth's ecosystems.
Indoor air pollution (see Airlog) and urban air quality are listed
as two of the world’s worst toxic pollution problems in the
2008 Blacksmith Institute World's Worst Polluted Places
report.
7. POLLUTANTS
Main articles: Pollutant and Greenhouse gas
Before flue-gas desulfurization was installed, the emissions from this
power plant in New Mexico contained excessive amounts of sulfur
dioxide.
Schematic drawing, causes and effects of air pollution: (1)
greenhouse effect, (2) particulate contamination, (3) increased UV
radiation, (4) acid rain, (5) increased ground level ozone
concentration, (6) increased levels of nitrogen oxides.
An air pollutant is a substance in the air that can have adverse
effects on humans and the ecosystem. The substance can be solid
particles, liquid droplets, or gases. A pollutant can be of natural
origin or man-made. Pollutants are classified as primary or
secondary. Primary pollutants are usually produced from a process,
such as ash from a volcanic eruption. Other examples include
carbon monoxide gas from motor vehicle exhaust, or the sulfur
dioxide released from factories. Secondary pollutants are not
emitted directly. Rather, they form in the air when primary pollutants
react or interact. Ground level ozone is a prominent example of a
secondary pollutant. Some pollutants may be both primary and
secondary: they are both emitted directly and formed from other
primary pollutants.
8. MAJOR PRIMARY POLLUTANTS PRODUCED BY
HUMAN ACTIVITY INCLUDE:
SOx) - particularly sulfur dioxide, a chemical compound with the
formula SO2. SO2 is produced by volcanoes and in various industrial
processes. Coal and petroleum often contain sulfur compounds, and
their combustion generates sulfur dioxide. Further oxidation of
SO2, usually in the presence of a catalyst such as NO2, forms
H2SO4, and thus acid rain.[2] This is one of the causes for concern
over the environmental impact of the use of these fuels as power
sources.
Nitrogen oxides:- (NOx) - Nitrogen oxides, particularly nitrogen
dioxide, are expelled from high temperature combustion, and are
also produced during thunderstorms by electric discharge. They can
be seen as a brown haze dome above or a plume downwind of
cities. Nitrogen dioxide is a chemical compound with the formula
NO2. It is one of several nitrogen oxides. One of the most prominent
air pollutants, this reddish-brown toxic gas has a characteristic
sharp, biting odor.
Carbon monoxide:- (CO)- CO is a colorless, odorless, toxic yet
non-irritating gas. It is a product by incomplete combustion of fuel
such as natural gas, coal or wood. Vehicular exhaust is a major
source of carbon monoxide.
9. GLOBAL WARMING
VOCs are a well known outdoor air pollutant. They
are categorized as either methane (CH4) or nonmethane (NMVOCs). Methane is an extremely
efficient greenhouse gas which contributes to
enhanced global warming. Other hydrocarbon
VOCs are also significant greenhouse gases
because of their role in creating ozone and
prolonging the life of methane in the atmosphere.
This effect varies depending on local air quality.
The aromatic NMVOCs benzene, toluene and
xylem are suspected carcinogens and may lead to
leukemia with prolonged exposure. 1,3-butadiene
is another dangerous compound often associated
with industrial use.
10. PARTICULATES
Particulates, alternatively referred to as particulate matter
(PM), atmospheric particulate matter, or fine particles, are
tiny particles of solid or liquid suspended in a gas. In
contrast, aerosol refers to combined particles and gas.
Some particulates occur naturally, originating from
volcanoes, dust storms, forest and grassland fires, living
vegetation, and sea spray. Human activities, such as the
burning of fossil fuels in vehicles, power plants and various
industrial processes also generate significant amounts of
aerosols. Averaged worldwide, anthropogenic aerosols—
those made by human activities—currently account for
approximately 10 percent of our atmosphere. Increased
levels of fine particles in the air are linked to health hazards
such as heart disease, altered lung function and lung
cancer.
11. OZONE LAYER
connected to airborne fine particles are linked to cardiopulmonary disease.
Toxic metals, such as lead and mercury, especially their compounds.
Chlorofluorocarbons (CFCs) - harmful to the ozone layer; emitted from products
currently banned from use <-These are gases which are released from air conditioners, refrigerators, aerosol
sprays, etc. CFC's on being released into the air rises to stratosphere. Here they
come in contact with other gases and damage the ozone layer. This allows
harmful ultraviolet rays to reach the earth's surface. This can lead to skin
cancer, disease to eye and can even cause damage to plants.
Ammonia (NH3) - emitted from agricultural processes. Ammonia is a compound
with the formula NH3. It is normally encountered as a gas with a characteristic
pungent odor. Ammonia contributes significantly to the nutritional needs of
terrestrial organisms by serving as a precursor to foodstuffs and fertilizers.
Ammonia, either directly or indirectly, is also a building block for the synthesis of
many pharmaceuticals. Although in wide use, ammonia is both caustic and
hazardous.
Odors — such as from garbage, sewage, and industrial processes
Radioactive pollutants - produced by nuclear explosions, nuclear events, war
explosives, and natural processes such as the radioactive decay of radon.
12. CFC
connected to airborne fine particles are linked to cardiopulmonary disease.
Toxic metals, such as lead and mercury, especially their compounds.
Chlorofluorocarbons (CFCs) - harmful to the ozone layer; emitted from
products currently banned from use <-These are gases which are released from air conditioners, refrigerators,
aerosol sprays, etc. CFC's on being released into the air rises to
stratosphere. Here they come in contact with other gases and damage the
ozone layer. This allows harmful ultraviolet rays to reach the earth's surface.
This can lead to skin cancer, disease to eye and can even cause damage to
plants.
Ammonia (NH3) - emitted from agricultural processes. Ammonia is a
compound with the formula NH3. It is normally encountered as a gas with a
characteristic pungent odor. Ammonia contributes significantly to the
nutritional needs of terrestrial organisms by serving as a precursor to
foodstuffs and fertilizers. Ammonia, either directly or indirectly, is also a
building block for the synthesis of many pharmaceuticals. Although in wide
use, ammonia is both caustic and hazardous.
Odors — such as from garbage, sewage, and industrial processes
Radioactive pollutants - produced by nuclear explosions, nuclear events,
war explosives, and natural processes such as the radioactive decay of
radon.
13. Secondary
pollutants include
Particulates created from gaseous primary pollutants and compounds in photochemical
smog. Smog is a kind of air pollution. Classic smog results from large amounts of coal
burning in an area caused by a mixture of smoke and sulfur dioxide. Modern smog does
not usually come from coal but from vehicular and industrial emissions that are acted on
in the atmosphere by ultraviolet light from the sun to form secondary pollutants that also
combine with the primary emissions to form photochemical smog.
Ground level ozone (O3) formed from NOx and VOCs. Ozone (O3) is a key constituent of
the troposphere. It is also an important constituent of certain regions of the stratosphere
commonly known as the Ozone layer. Photochemical and chemical reactions involving it
drive many of the chemical processes that occur in the atmosphere by day and by night.
At abnormally high concentrations brought about by human activities (largely the
combustion of fossil fuel), it is a pollutant, and a constituent of smog.
Peroxyacetyl nitrate (PAN) - similarly formed from NOx and VOCs.
Minor air pollutants include:
A large number of minor hazardous air pollutants. Some of these are regulated in USA
under the Clean Air Act and in Europe under the Air Framework Directive
A variety of persistent organic pollutants, which can attach to particulates
14. US AIRWAYS
US Airways is a major U.S. airlzzine owned by the American Airlines Group. It
operates an extensive international and domestic network, with 193 destinations in
24 countries in North America, South America, Europe, and the Middle East.
The airline is a member of the Star Alliance and utilizes a fleet of 343mainline jet
aircraft, as well as 278 regional jet and turbo-prop aircraft operated by contract and
subsidiary airline as US Airways Express. The carrier operates the US Airways
Shuttle, a US Airways brand which provides hourly service between Boston, New
York City, and Washington, D.C. As of October 2013, US Airways employed 32,312
people worldwide and operated 3,028 daily flights (1,241 US Airways Mainline, 1,790
US Airways Express).
In February 2013, American Airlines and US Airways announced plans to merge,
creating the largest airline in the world. The holding companies of American and US
Airways merged effective December 9, 2013. In preparation for their eventual
integration, the airlines began offering reciprocal frequent flyer benefits on January 7,
2014,and US Airways has announced plans to leave Star Alliance to
join Oneworld as an affiliate member of American Airlines on March 31, 2014. The
combined airline will carry the American Airlines name and branding, and will
maintain the existing US Airways hubs in Charlotte, Philadelphia, and Phoenix for a
period of at least five years under the terms of a settlement with the Department of
Justice and several state attorneys-general. US Airways management will run the
15. ACID RAIN
Acid rain:- is a rain or any other form
of precipitation that is unusuallyacidic, meaning that it
possesses elevated levels of hydrogen ions (low pH). It
can have harmful effects on plants, aquatic animals and
infrastructure. Acid rain is caused by emissions of sulfur
dioxide
andnitrogen
oxide,
which
react
with
the water molecules in the atmosphere to produce acids.
Governments have made efforts since the 1970s to
reduce
the
release
of
sulfur
dioxide
into
the atmospherewith positive results. Nitrogen oxides can
also be produced naturally by lightning strikes and sulfur
dioxide is produced by volcaniceruptions. The chemicals
in acid rain can cause paint to peel,corrosion of steel
structures such as bridges, and erosion of stone statues.
16. ACID corrosive effect of polluted, acidic city air on limestone and marble was noted in
RAIN HISOTRY
The
the 17th century by John Evelyn, who remarked upon the poor condition of
the Arundel marbles. Since the Industrial Revolution, emissions of sulfur dioxide and
nitrogen oxides into the atmosphere have increased.[In 1852, Robert Angus
Smith was the first to show the relationship between acid rain and atmospheric
pollution in Manchester, England.
Though acidic rain was discovered in 1853, it was not until the late 1960s that
scientists began widely observing and studying the phenomenon.[he term "acid rain"
was coined in 1872 by Robert Angus Smith. Canadian Harold Harvey was among the
first to research a "dead" lake. Public awareness of acid rain in the U.S increased in
the 1970s after The New York Times published reports from the Hubbard Brook
Experimental Forest in New Hampshire of the myriad deleterious environmental
effects shown to result from it.
Occasional pH readings in rain and fog water of well below 2.4 have been reported in
industrialized areas. Industrial acid rain is a substantial problem in China and Russia
and areas downwind from them. These areas all burn sulfur-containing coal to
generate heat and electricity.[
The problem of acid rain has not only increased with population and industrial
growth, but has become more widespread. The use of tall smokestacks to reduce
local pollution has contributed to the spread of acid rain by releasing gases into
regional atmospheric circulation.[Often deposition occurs a considerable distance
downwind of the emissions, with mountainous regions tending to receive the greatest
deposition (simply because of their higher rainfall). An example of this effect is the low
pH of rain which falls in Scandinavia.
17. ACID RAIN HISOTRY
n 1980, the U.S. Congress passed an Acid Deposition Act.[This Act established an 18-year
assessment and research program under the direction of the National Acidic Precipitation
Assessment Program (NAPAP). NAPAP looked at the entire problem from a scientific perspective.
It enlarged a network of monitoring sites to determine how acidic the precipitation actually
was, and to determine long term trends, and established a network for dry deposition. It looked at
the effects of acid rain and funded research on the effects of acid precipitation on freshwater and
terrestrial ecosystems, historical buildings, monuments, and building materials. It also funded
extensive studies on atmospheric processes and potential control programs.
From the start, policy advocates from all sides attempted to influence NAPAP activities to support
their particular policy advocacy efforts, or to disparage those of their opponents.the U.S.
Government's scientific enterprise, a significant impact of NAPAP were lessons learned in the
assessment process and in environmental research management to a relatively large group of
scientists, program managers and the public.[ In 1991, DENR provided its first assessment of acid
rain in the United States. It reported that 5% of New England Lakes were acidic, with sulfates
being the most common problem. They noted that 2% of the lakes could no longer support Brook
Trout, and 6% of the lakes were unsuitable for the survival of many species of minnow.
Subsequent Reports to Congress have documented chemical changes in soil and freshwater
ecosystems, nitrogen saturation, decreases in amounts of nutrients in soil, episodic
acidification, regional haze, and damage to historical monuments.
Meanwhile, in 1989, the U.S. Congress passed a series of amendments to the Clean Air Act. Title
IV of these amendments established the Acid Rain Program, a cap and trade system designed to
control emissions of sulfur dioxide and nitrogen oxides. Title IV called for a total reduction of about
10 million tons of SO2 emissions from power plants. It was implemented in two phases. Phase I
began in 1995, and limited sulfur dioxide emissions from 110 of the largest power plants to a
combined total of 8.7 million tons of sulfur dioxide. One power plant in New England (Merrimack)
was in Phase I. Four other plants (Newington, Mount Tom, Brayton Point, and Salem Harbor) were
added under other provisions of the program. Phase II began in 2000, and affects most of the
power plants in the country.
During the 1990s, research continued. On March 10, 2005, EPA issued the Clean Air Interstate
Rule (CAIR). This rule provides states with a solution to the problem of power plant pollution that
drifts from one state to another. CAIR will permanently cap emissions of SO2and NOx in the
eastern United States. When fully implemented, CAIR will reduce SO2 emissions in 28 eastern
states and the District of Columbia by over 70% and NOx emissions by over 60% from 2003
levels.[