Faculty of allied medical science
Environmental health(NREH-101)
Air pollution
SupervisionProf.dr/Mervat Salah
Outcomes
1-To know the meaning of air pollution2-To differentiate between outdoor and indoor pollution3-To know types of air pollution4-To understand the ways to control air pollution
AIR POLLUTIONType of Air pollution:- outdoor pollution – indoor pollution
Sources of out door pollution Combustion of fuel (natural gas, petroleum, coal and
wood) Industrial process Natural process (Volcanic)
Carbon oxides (CO)
Nitrogen oxides and nitric acid (NO, HNO3)
Sulfur dioxide and sulfuric acid (SO2, H2SO4)
Particulates (SPM)
Ozone (O3)
Volatile organic compounds (VOCs)
)
Types of Major Air Pollutants
Pollutants Pollutants can be classified as either primary or secondary- Primary pollutants are substances directly emitted from a process, such
as the carbon monoxide gas from a motor vehicle exhaust or sulfur dioxide released from factories.
- Secondary pollutants are not emitted directly. Rather, they form in the
air when primary pollutants react or interact. An important example of a secondary pollutant is ground level ozone
Sources and Types of Air Pollutants
Environmental challenges
• Green house effect: Increasing global temperature. Scientists predicting that earth's temperature will increase by 3-40C by year 2030 if the pollution continues to increase at the same pace.
• Ozone depletion: As ozone layer in the upper
atmosphere absorbs incoming harmful ultraviolet radiation but it is now getting thinner & more UVs are reaching in to earth creating different disease like cancer& eye problems.
• Photochemical smog: In 1952 London was covered by smog for 10 days .This smog was caused by fog, smoke, ash,& SO2 plus NO2.Sunlight played a great role in the formation of this smog .Acid rain: is caused by oxides of nitrogen & sulphur.It increases acidity of soil & effects the growth of trees & plants.
Acid Deposition• Sulfur dioxides and nitrogen oxides• Wet and dry deposition• Acid rain• Regional air pollution
– Midwest coal-burning power plants– Prevailing winds
Fig. 15-4, p. 351
Lakes in deepsoil high in limestoneare buffered
Lakes in shallow soillow in limestonebecome acidic
Wet acid deposition(droplets of H2SO4 andHNO3 dissolved in rainand snow)
Dry acid deposition(sulfur dioxide gasand particles ofsulfate and nitrate salts)
Windborne ammonia gasand some soil particles partiallyneutralize acids and form drysulfate and nitrate salts
Sulfur dioxide(SO2) and NO
Nitric oxide (NO)
Acid fog
Transformation to sulfuric acid (H2SO4) and nitric acid (HNO3)
Wind
Acid Deposition
Effects Of Pollution
• Respiratory diseases in human
• Toxic metal leaching
• Structural damage
• Kills fish and other aquatic organisms• Leaches plant nutrients from soil
• Acid clouds and fog at mountaintops
Acid Rain
SO2 & NOX
+water
SEASea LakeFactories, Transportation
Solar Radiation
H2SO4 (Sulphuric Acid)HNO3 (Nitric Acid)
The Greenhouse Effect
Earth’s natural greenhouse effect
Natural greenhouse gasesWater vapor (H2O)Carbon dioxide (CO2)Methane (CH4)Nitrous Oxide (N2O)
Enhanced greenhouse effect Global warming
Effect of Global warming• Rise in average global surface temperature• Changes in glaciers, rainfall patterns,
hurricanes• Droughts and floods. Threat to biodiversity• Decreased food production• Diseases (Threats to human health)• Economic and social disruption
• Rising sea levels• Extreme weather
Government Roles in Reducing the Threat of Climate Change (1)
• Regulate carbon dioxide as a pollutant
• Carbon taxes
• Cap total CO2 emissions
• Subsidize energy-efficient technologies
• Technology transfers
Photochemical reactions
Photochemical smogBrown-air smog
Sources
Climate effects
Urban areas
Photochemical Smog
A
MethaneCarbon Dioxide Nitrous oxideOzone
EarthEarth
Carbon Dioxide
50%
Methane 18%
Chlorofluorocarbons
14%
Ozone 12%
Nitrous oxide
06%Green house gases in natural condition insulates the earth against extreme of temperature by limiting both incoming solar radiation & escape of reradiated heat in to space.
This natural balance may be distorted by Green House Effect as gases such as carbon dioxide have built up in the atmosphere trapping more heat
sun
Infra-red radiation
Atmosphere
Surface Temperature normal
Some reradiated heat reflected back to earth
Atmosphere
sun
Surface Temperature increases
More reradiated heat reflected back to earth
Less reradiated heat escapes in to space
Some reradiated heat escapes in to space
sun
Contribution of different gases to cause green house effect
H2O WaterNO2
Nitrogen dioxide
Hydrocarbons
O2
Molecular Oxygen
HNO3 Nitric Acid
PANs Peroxyacyl nitrates
Aldyhydes (e.g. Formaldehyde)
O3 Ozone
O Atomic Oxygen
NO Nitric Oxide
Ultraviolet Radiation
Photochemical Smog
Ozone Layer thinning• Affect on seasonal changes
• Causes – chlorofluorocarbons (CFCs) that uses in:
• Coolants in air conditioners and refrigerators
• Propellants in aerosol cans
• Cleaning solutions for electronic parts
• Fumigants
• Bubbles in plastic packing foam
Ultraviolet rays from Sun
The Ozone layer in stratosphere blocks these harmful UV rays
Chlorofluorocarbons are entering in to atmosphere releasing chlorine. The chlorine than break down the ozone
The chlorine released from CFCs break down the ozone molecule.
chlorine
ozone
More ultraviolet radiations are reaching in to earths surface as there is a whole in ozone layer.
Oxygen
Whole in Ozone layer
Reversing Ozone Depletion• Stop producing ozone-depleting chemicals
• Slow recovery
• Montreal Protocol
• Copenhagen Protocol
• International cooperation
Indoor air qualityIndoor air quality (IAQ) is a term referring to
the air quality within and around buildings and structures.
IAQ can be affected by microbial contaminants (mold, bacteria), gases (including carbon monoxide, radon, volatile organic compound and particulates) .
Major Indoor Air Pollutants• Tobacco smoke
• Formaldehyde
• Radioactive radon-222 gas
• Very small particles
• Sick-building syndrome (SBS)
• Developing countries – Indoor cooking and heating
Air Pollution and the Human Respiratory System
• Natural protective system
• Lung cancer, chronic bronchitis, emphysema, asthma
• Premature deaths
Air Pollutants and its impact on human health
Particulate MatterDust and smoke particles cause irritation of the respiratory tract and produce bronchitis, asthma and lung diseases.Dust and smoke function as nuclei for condensation of water vapors and produce smog which attract chemicals like SO2, H2S, NO2,etc. Smog not only reduce visibility but is also harmful due to its contained chemicals.
NOISE POLLUTIONThe term noise is applied to the sound that cause irritation on hearing of healthy human being.
Sources Transport noise--- Originates from road traffic (vehicular), air craft and rail traffic. Industrial noise--- It produced by presses; punch and stamp machine, pneumatic drills, milling machines, cutter and routers, dust extractors. etc. Domestic noise--- It is generated from domestic appliance like washing machines, spin dryers, food mixer, sink waste grinder and vacuum cleaner.
Effects Of Noise PollutionHearing damage from noise exposure
Pathological and Physiological disorders
The impact of noise may cause permanent
hearing loss due to the exposure to noise
levels exceeding 90 dB
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;
What is sick building syndrome ?
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
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.
Control of Indoor Air Pollution
Questions
1-Sources of out door pollution are……………….2-Effects Of Noise Pollution are……………3-Two of Effects Of Noise Pollution are…………and………4- Source-isolation strategy is used in situations where a source…………..5- primary pollutants are substances directly emitted from a process, such as the ……………from a ............or ……..released from ……………..
6-What is sick building syndrome ? And it is effect on the health status of human being ?
7- What are the environmental challenges?
8-What are the classification of pollutants ?
Recommended text book
• Basic Environmental Health