Transcript File

Faculty of Medicine
Introduction to Community Medicine Course
(31505201)
Unit 3 Public Health/Environmental Health
Air Pollution
By
Hatim Jaber
MD MPH JBCM PhD
11-10-2016
1
Introduction to Unit 3
Public Health and Environment
5 lectures
• Introduction to Public Health and Environment-- 910-2016
• Environment 1- Air pollution11-10-2016
• Environment 2- Water Quality and Food Safety - 1310-2016 ??????????????
• Environment 3 -Waste Management --16-10-2016
• Occupational Health 4 – 18-10-2016
2
Presentation outline
Time
Air Pollution : Definition and Health
Impact
Outdoor and Indoor Air Pollution
12:00 to 12:10
12:10 to 12:20
Global Warming
12:20 to 12:30
Ozone Depletion
12:30 to 12:40
Temperature Inversion
12:40 to 12:50
Controlling Air Pollution
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The four types of
Atmosphere
• Troposphere: 8-18 km, close to
earth surface
• Stratosphere: up to 50km,
OZONE- absorbs harmful ultraviolet
radiation from sun
• Mesosphere: > 50 km
• Thermosphere and
Exosphere= upper
atmosphere
4
Man Made Environment
(Socio-cultural)
• Cultural OR man made
environment : It
includes
1)Industries,
2)Transport and
communication,
3)Population,
4)Traditions,
5)Political situations
etc.
5
Environmental
sustainability: ‫االستدامة‬
• Improvements in the standard of living
that do not cause long-term damage to
the environment that impact future
generations. and it includes:
•
•
•
•
•
1. Protecting biodiversity
2. Stopping human caused climate change
3. Elimination of acid rain
4. Elimination of damage to ozone layer
5. Reduction of pollution (air, water, noise,
etc.)
• 6. Management of resources e.g. fish, water
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Air Pollution : Definition and Health Impact
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Air pollution and Ventilation
Air pollution;
is the introduction of chemicals, particulate matter,
or biological material-- that cause harm discomfort
to humans or other living organisms, or damages the
natural environment,-- into the atmosphere.
OR Chemicals added to the atmosphere by natural events or
human activities in high enough concentrations to be
harmful
Ventilation :
A process, whereby air is supplied and removed from an
indoor space by natural or mechanical means.
Why ventilation is needed indoors?
To remove heat or moisture OR to reduce the
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concentration of one OR more indoor pollutants.
Atmosphere as a Resource
• Atmospheric
Composition
– Nitrogen 78.08%
– Oxygen 20.95%
– Argon 0.93%
– Carbon dioxide 0.04%
• Ecosystem services
– Blocks UV radiation
– Moderates the climate
– Redistributes water in
the hydrologic cycle
Types and Sources of Air Pollutants
• Two categories
– Primary Air Pollutant
• Harmful substance that is emitted
directly into the atmosphere
– Secondary Air Pollutant
• Harmful substance formed in the
atmosphere when a primary air
pollutant reacts with substances
normally found in the atmosphere or
with other air pollutants
Major Air Pollutants
Major Classes of Air Pollutants
•
•
•
•
•
•
Particulate Material
Nitrogen Oxides
Sulfur Oxides
Carbon Oxides
Hydrocarbons
Ozone
Particulate Material
• Thousands of different solid or liquid particles
suspended in air
– Includes: soil particles, soot, lead, asbestos, sea
salt, and sulfuric acid droplets
• Dangerous for 2 reasons
– May contain materials with toxic or carcinogenic
effects
– Extremely small particles can become lodged in
lungs
Nitrogen and Sulfur Oxides
• Nitrogen Oxides
– Gases produced by the chemical interactions
between atmospheric nitrogen and oxygen at high
temperature
– Problems
• Greenhouse gases
• Cause difficulty breathing
• Sulfur Oxides
– Gases produced by the chemical interactions
between sulfur and oxygen
– Causes acid precipitation
Carbon Oxides and Hydrocarbons
• Carbon Oxides
– Gases carbon monoxide (CO) and carbon dioxide
(CO2)
– Greenhouse gases
• Hydrocarbons
– Diverse group of organic compounds that contain
only hydrogen and carbon (ex: CH4- methane)
– Some are related to photochemical smog and
greenhouse gases
Ozone
• Tropospheric Ozone
– Man- made pollutant in the lower atmosphere
– Secondary air pollutant
– Component of photochemical smog
• Stratospheric Ozone
– Essential component that screens out UV
radiation in the upper atmosphere
– Man- made pollutants (ex: CFCs) can destroy it
Environmental Risk Factors and
Health:
• The evidence shows that environmental risk
factors play a role in more than 80% of the
diseases regularly reported by the World
Health Organization.
• Globally, nearly one quarter of all deaths and
of the total disease burden can be attributed
to the environment.
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Effects of Air Pollution
• Low level exposure
– Irritates eyes
– Causes inflammation of respiratory tract
• Can develop into chronic respiratory diseases
‫==ملخص‬Health Effects of Air Pollution
• Sulfur Dioxide and Particulate material
– Irritate respiratory tract and impair ability of
lungs to exchange gases
• Nitrogen Dioxides
– Causes airway restriction
• Carbon monoxide
– Binds with iron in blood hemoglobin
– Causes headache, fatigue, drowsiness, death
• Ozone
– Causes burning eyes, coughing, and chest
discomfort
Children and Air Pollution
• Greater health threat to children than adults
– Air pollution can restrict lung development
– Children breath more often than adults
• Children who live in high ozone areas are
more likely to develop asthma
Air Pollution Around the World
• Air quality is deteriorating rapidly in
developing countries
• Shenyang, China
– Residents only see sunlight a few weeks
each year
• Developing countries have older cars
– Still use leaded gasoline
• 5 worst cities in world
– Beijing, China; Mexico City, Mexico;
Shanghai, China; Tehran, Iran; and
Calcutta, India
Case-In-Point Air Pollution in Beijing and
Mexico City
• Beijing (left)
• Mexico City (above)
Urban Air Pollution
• Photochemical Smog (ex: Los Angeles below)
– Brownish-orange haze formed by chemical reactions involving
sunlight, nitrogen oxide, and hydrocarbons
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Outdoor and Indoor Air Pollution
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INDOOR AIR POLLUTION
-Indoor air pollutants may be up to 100 times
higher than outdoor levels. (Environmental
protection agency).
-Most people spend 90% of their time indoors.
(American Lung Association)
Dirty ventilation systems are a 50% contributor to
sick building syndrome. (Healthy Buildings
International).
INDOOR AIR POLLUTION
-50% of all illnesses are either caused or aggravated
by polluted indoor air. (American College of
Allergists).
-Legionnaire’s disease was spawned in air
conditioning ducts. (ALA)
-Indoor airpollution is the primary cause in as
many as 50 million cases of occupational chronic
respiratory disease each year. (World Health
Organization).
-
What Causes Indoor Air Pollution??
· Air tightness of buildings
· Poorly designed air conditioning and
ventilation systems
· Indoor sources of pollution
· Outdoor sources of pollution
What Causes Indoor Air Pollution??
Air Tightness in Buildings Causes inadequate supply of
fresh air, as a result, negative pressure develops, which
causes:
· Ground level pollutants, e.g. CO, Radon etc.to be
drawn inside the buildings.
· Release of odor (Bioaerosols) and other pollutants.
· Pull outside polluted air from vents, cracks and
openings and increase dust, pollen etc.
· Causes “Sick Building Syndrome”.
What Causes Indoor Air Pollution??
Poorly Designed Air Conditioning Systems Results into the
production of fungi, molds and other sickness
causing microbes.
Problems of IAQ Enclosed spaces inhabited by
humans produce following effects· Reduction in oxygen level of spaces.
· Increase in CO2 level.
· Increase in temperature.
· Increase in humidity
· Increase in Bioaerosols and odor
How can I tell that indoor air is
contaminated?
Sniff the air. The nose is the best
odor and gas detector, and a good
particle detector as well, especially
when first entering a contaminated
environment.
Health Effects of Indoor Air Pollutants
Health effects due to indoor air pollutants may be
short- as well as long-term.
Short-term problems include a stuffy, odorous
environment and symptoms such as burning
eyes, skin irritation, and headaches.
Long-term health problems have a longer
latency period or are chronic in nature.
Health conditions involving some allergic
reactions, including hypersensitivity
pneumonitis, allergic rhinitis, and some types
of asthma, are triggered by bioaerosols.
Control of Indoor Air Pollution
Basic approaches to control indoor air pollution include
source control, source isolation, increased ventilation,
dehumidification, and the use of filters.
Possible sources of contamination are eliminated in a
source-control strategy. Examples include banning
smoking in public buildings.
Source-isolation strategy is used in situations where a
source cannot be completely eliminated. For instance,
copy machine areas, food service stations, and bathrooms
are often separately vented outside buildings to avoid the
recirculation of return air.
Low humidity should be maintained inside a house to limit
the growth of such bacteria.
Indoor air pollution can be a very serious problem. You
should be aware of the potential health hazards within
your home, and you should also know how to effectively
reduce the levels of air pollutants
What is sick building syndrome ?
The feeling of illness among majority of
occupants of a conditioned space is called
“Sick Building Syndrome”.
A variety of illness symptoms reported by
occupants in sick buildings are – Headache,
fatigue, irritation in eyes, nose and throat,
shortness of breathe etc.
Causes
Inadequate ventilation
insufficient supply of outside air; poor mixing;
fluctuations in temperature & humidity;
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Indoor Air Pollution - Radon
Radon
Radon is the second leading cause of lung cancer,
following smoking. Radon is odorless, colorless, and
tasteless. It is a naturally occurring radioactive gas
resulting from the decay of radium, itself a decay
product of uranium .
Radon is a radioactive gas that comes from the decay of
uranium in the Earth. It comes up through cracks in
the ground and can get into your basement. It can
accumulate in the basement up to levels which can
cause lung cancer.
Smokers are at an especially high risk of getting lung
cancer from radon.
Outdoor Air Pollution
Global warming-Climate Change
Ozone Depletion
Temperature Inversion
40
Sources of Outdoor Air Pollution
• Two main sources
– Transportation
– Industry
• Intentional forest
fires is also high
What is Climate Change?
 Global warming and climate change are terms for
the observed century-scale rise in the
average temperature of the Earth's climate
system and its related effects
 Climate is the average weather at a given point and
time of year, over a long period (typically 30 years).
 We expect the weather to change a lot from day to
day, but we expect the climate to remain relatively
constant.
 If the climate doesn’t remain constant, we call it
climate change.
Global Warming
Global Warming “Climate changes”
43
What cause the temperature of the
atmosphere to go up?
• There are many possible mechanisms that can cause the
warming of the atmosphere, for example:
– Natural variation – the climate becomes warmer by internal chaotic dynamics
of the earth-atmosphere system (that is, no external influence).
– Solar activity – either direct increase of solar energy output or indirect
“trigger” mechanisms due to solar activity (though nobody knows how) may
cause the surface temperature to go up.
– Greenhouse effect – increasing “greenhouse” gases such
as CO2, CH4, NO, CFC,…etc. (actually H2O is very efficient,
too, but at present it is assumed to be in steady state).
• The last one is presently thought to be the most likely cause of the global
warming.
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Earth’s Atmospheric Gases
Nitrogen (N2)
Oxygen (O2)
NonGreenhouse
Gases
99%
Water (H2O)
Carbon Dioxide (CO2)
Methane (CH4)
Greenhouse
Gases
1%
Greenhouse gases
• The greenhouse effect is the process by
which absorption and emission of infrared
radiation by gases in
planet's atmosphere warm its lower
atmosphere and surface.
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Greenhouse gases
• Greenhouse gases are a group of
compounds that are able to trap heat (long
wave radiation) in the atmosphere, keeping
the Earth's surface warmer than it would
be if they were not present.
• These gases are the fundamental cause of
the greenhouse effect.
• Increases in the amount of greenhouse
gases in the atmosphere enhances the
greenhouse effect which is creating global
warming and consequently climate change.
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• Increases in the amount of greenhouse gases
in the atmosphere enhances the greenhouse
effect which is
• creating global warming and
• consequently climate change.
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The consequences of global warming
phenomenon are:
1.
2.
3.
4.
5.
Extreme heat:
Natural disasters
Poor air quality:
Allergens and other nuisances:
Spreading diseases:
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Possible impacts of climate change due to projected
changes in extreme weather and climate events
Ozone Depletion
51
Ozone Depletion in Stratosphere
• Ozone Protects earth from UV radiation
– Part of the electromagnetic spectrum with
wavelengths just shorter than visible light
Ozone Depletion in Stratosphere
• Ozone thinning/hole
– First identified in 1985 over
Antarctica
• Caused by
– human-produced bromine
and chlorine containing
chemicals
– Ex: CFCs
Effects of Ozone Depletion
• Higher levels of UVradiation hitting the
earth
– Eye cataracts
– Skin cancer (right)
– Weakened immunity
• May disrupt
ecosystems
• May damage crops
and forests
To summarize the health effects of exposure to
UVR as a result of Ozone depletion
• 1. 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.
• 2. Eye damage: Direct exposure to UV radiations can result in
photo-keratitis (snow blindness), and cataracts.
• 3. 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.
• 4. Accelerated aging of skin: Constant exposure to UV
radiation can cause photo allergy, which results in the
outbreak of rash in fair-skinned people.
• 5. Other effects: Ozone chemicals can cause difficulty in
breathing, chest pain, throat irritation, and impede lung
functioning.
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Recovery of Ozone Layer
• Montreal Protocol (1987)
– Reduction of CFCs
– Started using HCFCs (greenhouse gas)
• Phase out of all ozone destroying chemicals is
underway globally
• Satellite pictures in 2000 indicated that ozone
layer was recovering
• Full recovery will not occur until 2050
Acid Deposition
• Sulfur dioxide and nitrogen dioxide emissions
react with water vapor in the atmosphere and
form acids that return to the surface as either
dry or wet deposition
• pH scale
How Acid Deposition Develops
Acid Deposition and Forest Decline
Effects of Acid Deposition
• Declining Aquatic Animal
Populations
• Thin-shelled eggs prevent
bird reproduction
– Because calcium is
unavailable in acidic soil
• Forest decline
– Ex: Black forest in Germany
(50% is destroyed)
Temperature Inversion
62
Air Molecule Density
As you go higher in the atmosphere, air becomes
less dense.
The air molecules are spaced further apart
That is why it is hard to breathe at high altitudes.
That is also why it is colder at high altitudes
Heat is from molecule collisions.
Fewer molecules……Fewer collisions……Less heat!
Gravity pulls the air close to the earth
SO, The higher you go. . .The less dense the air . . .
The colder it gets!
Temperature Inversion
• A temperature inversion is when a layer
of warmer air covers the colder air at
ground level.
6
All Over Town
Lack of heavy cloud cover
Signs of a surface
inversion in the
early morning
Windless or light variable
wind
Ground Fog
Frost (or dew)
Controlling Air
Pollution