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Faculty of allied medical science Environmental health (NREH-101)

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Presentation on theme: "Faculty of allied medical science Environmental health (NREH-101)"— Presentation transcript:

1 Faculty of allied medical science Environmental health (NREH-101)

2 Air pollution Supervision Prof.dr/Mervat Salah

3 Outcomes 1-To know the meaning of air pollution 2-To differentiate between outdoor and indoor pollution 3-To know types of air pollution 4-To understand the ways to control air pollution

4 AIR POLLUTION Type 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)

5 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

6 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

7 Sources and Types of Air Pollutants

8 Environmental challenges Green house effect: Increasing global temperature. Scientists predicting that earth's temperature will increase by C 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,& SO 2 plus NO 2. 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.

9 Acid Deposition Sulfur dioxides and nitrogen oxides Wet and dry deposition Acid rain Regional air pollution – Midwest coal-burning power plants – Prevailing winds

10 Fig. 15-4, p. 351 Lakes in deep soil high in limestone are buffered Lakes in shallow soil low in limestone become acidic Wet acid deposition (droplets of H2SO4 and HNO3 dissolved in rain and snow) Dry acid deposition (sulfur dioxide gas and particles of sulfate and nitrate salts) Windborne ammonia gas and some soil particles partially neutralize acids and form dry sulfate 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

11 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

12 Acid Rain SO 2 & NO X + water SEA Sea Lake Factories, Transportation Solar Radiation H 2 SO 4 (Sulphuric Acid) HNO 3 (Nitric Acid)

13 The Greenhouse Effect Earths natural greenhouse effect Natural greenhouse gases Water vapor (H 2 O) Carbon dioxide (CO 2 ) Methane (CH 4 ) Nitrous Oxide (N 2 O) Enhanced greenhouse effect Global warming

14 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

15 Government Roles in Reducing the Threat of Climate Change (1) Regulate carbon dioxide as a pollutant Carbon taxes Cap total CO 2 emissions Subsidize energy-efficient technologies Technology transfers

16 Photochemical reactions Photochemical smog Brown-air smog Sources Climate effects Urban areas Photochemical Smog

17 A Methane Carbon Dioxide Nitrous oxide Ozone Earth Carbon Dioxide 50% Methane 18% Chlorofluoroc arbons 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

18 H2O Water NO 2 Nitrogen dioxide Hydrocarbons O 2 Molecular Oxygen HNO 3 Nitric Acid PANs Peroxyacyl nitrates Aldyhydes (e.g. Formaldehyde) O 3 Ozone O Atomic Oxygen NO Nitric Oxide Ultraviolet Radiation Photochemical Smog

19 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

20 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

21 Reversing Ozone Depletion Stop producing ozone-depleting chemicals Slow recovery Montreal Protocol Copenhagen Protocol International cooperation

22 Indoor air quality Indoor 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).


24 Major Indoor Air Pollutants Tobacco smoke Formaldehyde Radioactive radon-222 gas Very small particles Sick-building syndrome (SBS) Developing countries – Indoor cooking and heating

25 Air Pollution and the Human Respiratory System Natural protective system Lung cancer, chronic bronchitis, emphysema, asthma Premature deaths

26 Air Pollutants and its impact on human health Particulate Matter Dust 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 SO 2, H 2 S, NO 2,etc. Smog not only reduce visibility but is also harmful due to its contained chemicals.

27 NOISE POLLUTION The 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.

28 Effects Of Noise Pollution Hearing 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

29 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.

30 Causes: Inadequate ventilation, insufficient supply of outside air; poor mixing; fluctuations in temperature & humidity ; What is sick building syndrome ?

31 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

32 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

33 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 ……………..

34 6-What is sick building syndrome ? And it is effect on the health status of human being ? 7- What are the e 7- What are the environmental challenges? 8-What are the classification of pollutants ?

35 Recommended text book Basic Environmental Health

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