Transcript Earth’s atmosphere. Air pollution.

Earth’s atmosphere.
Air pollution.
Earth’s atmosphere
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is a layer of gases surrounding the planet
Earth and retained by the Earth's gravity.
It contains roughly
78%nitrogen,
21%oxygen,
0.97%argon,
0.04%carbon dioxide, and trace amounts of
other gases, in addition to water vapor.
An air pollutant can be a
chemical
 physical (particulate matter or dust)
 biological
agent that modifies the natural
characteristics of the atmosphere.
Worldwide air pollution is responsible
for large numbers of deaths and cases
of respiratory diseases.
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Health problems resulting
from air pollution
aggravated asthma
 bronchitis
 emphysema
 lung and heart diseases
 respiratory allergies
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Air quality standards
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In the United States there was issued the
Clean Air Act that has already reduced
concentrations of some pollutants.
The Clean Air Act sets numerical limits on the
concentrations of basic group of air pollutants
and provides reporting and enforcement
mechanisms.
The European Union follows the initiative.
Antropogenic (manmade)
sources of air pollution
Marine vessels
 Burning fossil fuels
 Burning wood, fireplaces, stoves,
furnaces and incinerators
 Combustion-fired power plants
 Controlled burn practices in agriculture
and forestry
 Motor vehicles
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Other antropogenic sources
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Chemicals, dust and crop waste burning in
farming.
Fumes from paint, varnish, aerosol sprays
and other solvents.
Waste deposition in landfills, which generate
mathane.
Military uses, as nuclear weapons, toxic
gases, and rocketry.
Oil refining, power plant operation and
industry.
Natural sources
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Methane, emitted by the digestion of food by
animals, for example cattle.
Pine trees, which emit
volatile organic
compounds (VOCs).
Radon gas from radioactive decay within the
Earth's crust.
Smoke and carbon monoxide from wildfires .
Volcanic activity, which produce sulfur,
chlorine , and ash particulates.
Dust from natural sources.
Indoor air pollution, or Indoor
air quality (IAQ)
Radon is a gas of carcinogenic
properties trapped inside houses.
 Formaldehyde is emitted by building
materials.
 Volatile
Organic
Compounds
(VOCs) are given off by paints and
solvents.
 Lead paint can degenerate into lead
containing dust and be inhaled.
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Indoor air pollution
Air fresheners, incense and other
scented items.
 Smoke from wood fires in stoves and
fireplaces.
 Arsenic and manganese in shower
water (damaging to inhale).
 Arsenic can be trapped in shower nozzle
filter.
 Pesticides.
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Indoor air pollution
Carbon monoxide from incomplete
combustion.
 Hydrogen sulfide, deadly sewer gas (to
stop it special traps are built into all
domestic plumbing).
 Tetrachloroethylene from dry cleaned
clothes.
 Asbestos from building materials.
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Smog
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is a type of air pollution; the word "smog" was coined in the
early 20th century as a portmanteau of the words smoke
and fog to refer to smoky fog. The word was then intended
to refer to what was sometimes known as pea soup fog, a
familiar and serious problem in London from the 19th
century to the mid 20th century. This kind of smog is
caused by the burning of large amounts of coal within
a city; this smog contains soot particulates from
smoke, sulfur dioxide and other components.
Modern smog, as found for example in Los Angeles, is a
type of air pollution derived from vehicular emission from
internal combustion engines and industrial fumes that
react in the atmosphere with sunlight to form
secondary pollutants that also combine with the primary
emissions to form photochemical smog.
Health effects of ground -level
ozone and photochemical
smog
Inflammation of breathing passages,
decreasing the lung’s working capacity,
shortness of breath, pain, wheezing,
and coughing.
 Eye and nose drying and irritation.
 It increases susceptibility to infectious
diseases.
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Carbon monoxide (CO)
is a colourless, odourless and tasteless
gas.
 is the product of incomplete combustion
 burns in air with a blue flame.
 is toxic as when inhaled, it takes the
place of oxygen in haemoglobin. It
binds haemoglobin 200-400times more
strongly
than
oxygen
producing
carboxyhaemoglobin.
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From 1999 through 2004 there were
439 unintentional, non-fire related
carbon monoxide poisoning deaths
annually in the U.S.
 In 2007, there were 2,302
hospitalizations for confirmed cases of
unintentional, non-fire related carbon
monoxide poisoning in the U.S.
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In 2009 there were 552 persons with
unintentional, non-fire related carbon
monoxide poisoning who received
hyperbaric oxygen treatment in the U.S.
Acute poisoning with CO
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The main manifestations of poisoning develop in the organ
systems most dependent on oxygen use, the central
nervous system and the heart. The initial symptoms of
acute carbon monoxide poisoning
include headache, nausea, malaise, and fatigue. These
symptoms are often mistaken for a virus such
as influenza or other illnesses such as food
poisoning or gastroenteritis. Headache is the most common
symptom of acute carbon monoxide poisoning; it is often
described as dull, frontal, and continuous. Increasing
exposure produces cardiac abnormalities including fast
heart rate, low blood pressure, and cardiac
arrhythmia.
Acute poisoning with CO
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Central nervous system symptoms
include delirium, hallucinations, dizziness, unstead
y gait, confusion, seizures, central nervous system
depression,unconsciousness, respiratory arrest,
and death. Less common symptoms of acute carbon
monoxide poisoning include myocardial ischemia, atrial
fibrillation, pneumonia, pulmonary edema, high blood
sugar, lactic acidosis, muscle necrosis, acute kidney
failure, skin lesions, and visual and auditory problems.
One classic sign of carbon monoxide poisoning is more
often seen in the dead rather than the living - people
have been described as looking pink-cheeked and
healthy.
Concentration
Symptoms
35 ppm (0.0035%)
Headache and dizziness
within six to eight hours of
constant exposure
100 ppm (0.01%)
Slight headache in two to
three hours
200 ppm (0.02%)
Slight headache within two
to three hours; loss of
judgment
400 ppm (0.04%)
Frontal headache within
one to two hours
800 ppm (0.08%)
Dizziness, nausea, and
convulsions within 45 min;
insensible within 2 hours
1,600 ppm (0.16%)
Headache, tachycardia,
dizziness, and nausea
within 20 min; death in less
than 2 hours
3,200 ppm (0.32%)
Headache, dizziness and
nausea in five to ten
minutes. Death within 30
minutes.
6,400 ppm (0.64%)
Headache and dizziness in
one to two minutes.
Convulsions, respiratory
arrest, and death in less
than 20 minutes.
12,800 ppm (1.28%)
Unconsciousness after 2–3
breaths. Death in less than
three minutes.
Chronic exposure to CO
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Chronic exposure to relatively low levels of carbon monoxide
may cause persistent headaches, lightheadedness,
depression, confusion, memory loss, nausea and
vomiting. It is unknown whether low-level chronic exposure
may cause permanent neurological damage. Typically, upon
removal from exposure to carbon monoxide, symptoms
usually resolve themselves. Chronic exposure may worsen
cardiovascular symptoms in some people. Chronic carbon
monoxide exposure might increase the risk of developing
atherosclerosis. Long-term exposures to carbon monoxide
present the greatest risk to persons with coronary heart
disease and in females who are pregnant
First aid in CO poisoning
Remove the victim from the exposure.
 Apply CPR if needed.
 Provide 100% oxygen for breathing.
 Hyperbaric
oxygen
increases
carboxyhaemoglobin dissociation.
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Carbon dioxide (CO2)
exists in Earth's atmosphere as a trace gas at a
concentration of 0.039% by volume
 Carbon dioxide is colorless. At low
concentrations, the gas is odorless. At higher
concentrations it has a sharp, acidic odor.
 At standard temperature and pressure, the
density of carbon dioxide is around 1.98 kg/m3,
about 1.5 times that of air.
 Is a greenhouse gas.
 In solid state it is called dry ice.
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plants absorb carbon dioxide, light,
and water to produce carbohydrate energy for themselves and oxygen as a
waste product.
 In medicine up to 5% of CO2 is added
to pure oxygen for stimaulation of
breathing after apnea and to stabilize
the O2/CO2 balance in blood.
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CO2 toxicity
CO2 is an asphyxiant gas and not
classified as toxic or harmful.
 Concentrations of 7% to 10% may
cause suffocation, manifesting as
dizziness, headache, visual and hearing
dysfunction, and unconsciousness
within a few minutes to an hour.
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Acute carbon dioxide physiological effect
is hypercapnia or asphyxiation sometimes known by
the names given to it by miners: blackdamp.
Blackdamp is primarily nitrogen and carbon dioxide
and kills via suffocation (having displaced
oxygen). Miners would try to alert themselves to
dangerous levels of blackdamp and other gasses in a
mine shaft by bringing a caged canary with them as
they worked. The canary is more sensitive to
environmental gasses than humans and as it became
unconscious would stop singing and fall off its perch.
Sulfur (sulphur) dioxide (SO2)
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Sulfur dioxide is the chemical compound with the
formula SO2. It is a toxic gas with a pungent,
irritating smell, that is released by volcanoes and in
various industrial processes. Since coal
and petroleum often contain sulfur compounds, their
combustion generates sulfur dioxide unless the sulfur
compounds are removed before burning the fuel.
Further oxidation of SO2, usually in the presence of a
catalyst such as NO2, forms H2SO4, and thus acid
rain.Sulfur dioxide emissions are also a precursor
to particulates in the atmosphere. Both of these
impacts are cause for concern over the
environmental impact of these fuels.
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Inhaling sulfur dioxide is associated with increased
respiratory symptoms and disease, difficulty in
breathing, and premature death. In 2008,
the American Conference of Governmental Industrial
Hygienists reduced the short-term exposure
limit from 5 ppm to 0.25 ppm.
Exposure to sulfur dioxide is associated with preterm
birth.
In the United States, the Center for Science in the
Public Interest lists the two food preservatives, sulfur
dioxide and sodium bisulfite, as being safe for human
consumption except for certain individuals who may
be sensitive to it, especially in large amounts
Acid rain
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or acid precipitation occurs when SO2 and
NOx are emitted into atmosphere, undergo
chemical transformations and are absorbred
by water droplets in clouds. Acid rain has pH
less than 5.6.
Acid rain accelerates weathering in
carbonate
rocks
and
accelerates
building weathering. It also contributes to
acidificaton of rivers, streams and
damage to conifer forests.
Oxides of nitrogen (NOx)
Nitric oxide (NO)
 Nitrogen dioxide (NO2)
 Dinitrogen monoxide (N2O)
 Dinitrogen trioxide (N2O3)
 Dinitrigen tetraoxide(N2O4)
 Dinitrogen pentaoxide (N2O5)
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Nitrogen oxides
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Nitrogen oxides are a mixture of gases that are composed of
nitrogen and oxygen. Two of the most toxicologically significant
nitrogen oxides are nitric oxide and nitrogen dioxide; both are
nonflammable and colorless to brown at room temperature.
Nitric oxide is a sharp sweet-smelling gas at room temperature,
whereas nitrogen dioxide has a strong, harsh odor and is a
liquid at room temperature, becoming a reddish-brown gas
above 70°F. Nitrogen oxides are released to the air from the
exhaust of motor vehicles, the burning of coal, oil, or natural
gas, and during processes such as arc welding, electroplating,
engraving, and dynamite blasting. They are also produced
commercially by reacting nitric acid with metals or cellulose.
Nitrogen oxides are used in the production of nitric acid,
lacquers, dyes, and other chemicals. Nitrogen oxides are also
used in rocket fuels, nitration of organic chemicals, and the
manufacture of explosives.
Oxides of nitrogen (NOx)
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are produced during combustion. The most
important source of NO2 is internal
combustion engines.
aggravate asthmatic conditions.
react with the oxygen in the air to produce
ozone.
can form nitric acid; when dissolved in
atmospheric moisture the result can be acid
rain damaging trees and forest ecosysytems.
NO2 is toxic by inhalation, causes lung edema.
Ozone (O3)
Is a triatomic molecule, consisting of
three oxygen atoms.
 The highest levels of ozone in the
atmosphere are in the stratosphere
(ozon layer is between 10 to 50km
above the surface). There it filters out
the short wavelengths (less than
320nm) of ultraviolet light.
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Ozone (O3)
Low level ozone or tropospheric ozone
is regarded as a pollutant by the WHO. It is
formed by the reaction of sunlight an air
containing hydrocarbons and nitrogen oxides
that to form ozone.
Ozone present in the upper troposphere acts
as a greenhouse gas absorbing some of
the infrared energy emitted by earth. Ozone
depletion
occurs
due
to
chlorofluorocarbons (CFCs or freons)
and bromofluorocarbons (halons).
At the earth’s surface ozone can harm lung
function and irritate respiratory system.
Ozone (O3)
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Ozone is produced by laser printers
photocopiers and arc welders.
Ozone is used for bleaching substances and
for killing bacteria, for water and food
disinfection, to deodorize air and objects, for
plactics processing, cleaning and bleaching of
fabrics.
In medicine to decontaminate operating
rooms.
Particulates
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Or particulate matter (PM) are tiny particles
of solid (a smoke) or liquid (an aerosol)
suspended in gas. They range in size from 10
nanometers to more than 100 micrometers in
diameter.
Some PM originate from volcanoes, dust
storms and forest fires.
Human activities, especially fossil fuels
burning also produce PM.
Pneumoconioses
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Are lung diseases caused by inhalaton
of dust. They can be fibrogenic
(caused by silica dust or asbestos) or
non fibrogenic.
Effects of asbestos
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Significant exposure to any type of
asbestos will increase the risk of lung
cancer, mesothelioma and
nonmalignant lung and pleural
disorders, including asbestosis, pleural
plaques, pleural thickening, and pleural
effusions.
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When asbestos fibers are inhaled, most
fibers are expelled, but some can
become lodged in the lungs and remain
there throughout life. Fibers can
accumulate and cause scarring and
inflammation. Enough scarring and
inflammation can affect breathing,
leading to disease.
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Inhaling longer, more durable asbestos fibers
(such as tremolite and other amphiboles)
contributes to the severity of asbestos-related
disorders.
Exposure to asbestos can increase the
likelihood of lung cancer, mesothelioma, and
non-malignant lung conditions such as
asbestosis (restricted use of the lungs due to
retained asbestos fibers) and changes in the
pleura (lining of the chest cavity, outside the
lung).
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Changes in pleura such as thickening, plaques,
calcification, and fluid around the lungs (pleural
effusion) may be early signs of asbestos exposure.
These changes can affect breathing more than
previously thought. Pleural effusion can be an early
warning sign for mesothelioma (cancer of the lining
of the lungs).
Most cases of asbestosis or lung cancer in workers
occurred 15 years or more after the person was first
exposed to asbestos.
Most cases of mesothelioma are diagnosed 30 years
or more after the first exposure to asbestos.
Asbestosis
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Results from heavy exposure to asbestos
Symptoms: shortness of breath, cough,
respiratory failure. There is also an increased
risk for lung cancer and mesothelioma.
Pathogenesis:
asbestos
fibres
cause
intersitial fibrosis in lower lobes.
There is no curative treatment. Oxygen
therapy relieves shortness of breath.
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Asbestosis is a serious,
progressive, long-term disease
of the lungs. Asbestosis is not a
cancer. Inhaling asbestos fibers
that irritate and inflame lung
tissues, causing the lung tissues
to scar, causes asbestosis. The
scarring makes it hard to
breathe and difficult for oxygen
and carbon dioxide pass
through the lungs. Asbestosis
generally progresses slowly.
The latency period for the onset
of asbestosis is typically 10-20
years after the initial exposure.
The disease can vary from
asymptomatic (no symptoms) to
disabling and potentially fatal.
Signs and Symptoms of
asbestosis can include:
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Shortness of breath is the primary symptom
A persistent and productive cough (a cough
that expels mucus)
Chest tightness
Chest pain
Loss of appetite
A dry, crackling sound in the lungs while
inhaling.
Mesothelioma
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Mesothelioma is a rare cancer, which
may affect the lining of the chest cavity,
outside the lung (pleura) or the
abdominal contents (peritoneum). Most
mesotheliomas are caused by exposure
to asbestos.
Lung Cancer
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Lung cancer is a malignant tumor
that invades and obstructs the
lung's air passages. Cigarette
smoking greatly increases the
likelihood of a person developing
lung cancer as the result of
asbestos exposure. The most
common symptoms of lung cancer
are cough, wheezing, unexplained
weight loss, coughing up blood, and
labored breathing. Other symptoms
of lung cancer include shortness of
breath, persistent chest pain,
hoarseness, and anemia. People
who develop these symptoms do
not necessarily have lung cancer,
but they should consult a physician
for advice.
Asbestosis
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Heavy
asbestos
fibres
cause
intersitial fibrosis
in lower lobes.
Silicosis
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Silica dust causes nodular lesions (nodular
fibrosis) in upper lobes.
Symptoms: tachypnea, shortness of breath,
cough, fatigue, changes in breathing pattern
(rapid breathing or shallow breathing), loss of
appetite, chest pain, fever, cyanosis, cor
pulmonale, respiratory insufficiency, patients
are particularly susceptible to tuberculosis
(silicotuberculosis).
Silicosis is an irreversible condition. There
is no cure.
Silicosis
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Silica dust causes
nodular
lesions
(nodular fibrosis) in
upper lobes.
Black lung disease
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Black lung disease is
a pneumoconiosis
caused by inhalation
of carbon dust and
silica dust by
workers in coal
miners.
Airborne diseases
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refers to any diseases which are caused by
pathogens and transmitted through the air.
These viruses and bacteria can be spread
through coughing, sneezing, laughing or
through close personal contact. These
pathogens ride on either dust particles or
small respiratory droplets and can stay
suspended in air and or are capable of
traveling distances on air currents.
Airborne diseases
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Tuberculosis
Anthrax (inhalational),
Chickenpox,
Influenza,
Measles,
Smallpox .
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Airborne diseases are most commonly seen in
unsanitary household conditions and overcrowded
areas. Also, these diseases thrive in areas of poverty
and poor hygienic conditions. Tuberculosis happens
to be one of the most leading causes of death in
adults from infectious diseases. Around 95% of
people suffering from this disease are from
developing areas in the world. Measles and
diphtheria are two diseases found in poverty
conditions, but over the years these diseases have
been eliminated due to vaccines in developed
countries.