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Basic laws of hygiene. Bases of preventive and current sanitary supervision. Sun radiation and health. Hygienic value of sun radiation, physical properties and chemical composition of air environment.

THE PLAN

Introduction.1. The definition of hygiene.2. The aim and tasks of hygiene.3. Basic methods of hygienic

researches. 4. Compositions and Structure of the

Atmosphere5. Natural Sources of Air Pollution6. Human-caused Air Pollution7. Indoor Air Pollution8. Effects of Air Pollution   Conclusions.

Introduction

HealthHealth

is defined as a state of complete is defined as a state of complete physical, mental and social well-physical, mental and social well-being and not merely absence of being and not merely absence of disease or infirmity.disease or infirmity.

To promote and maintain a state of positive health an

individual needs the following

prerequisites

Healthful shelter

Healthful shelter

Supply of fresh air and sunlight

Supply of fresh air and sunlight

  Balanced diet  Balanced diet

Safe and potable water supply

Safe and potable water supply

Adequate clothing hygienic

environmental sanitation

Adequate clothing hygienic

environmental sanitation

Protection from communicable and other avoidable afflictions

Protection from communicable and other avoidable afflictions

Complete sense of protection and security both socially and

economically

Complete sense of protection and security both socially and

economically

A congenial social and cultural

atmosphere

A congenial social and cultural

atmosphere

  Regulated way of life with proper rest and relaxation and good and simple habits

  Regulated way of life with proper rest and relaxation and good and simple habits

Hygiene is a basic preventive Hygiene is a basic preventive science in medicine. It science in medicine. It generalizes all dates of generalizes all dates of theoretical and clinical theoretical and clinical disciplines in the field of disciplines in the field of prophylaxis, integrates prophylaxis, integrates knowledge’s about complex knowledge’s about complex influence of an environment for influence of an environment for health of the man, work out health of the man, work out principles and systems of principles and systems of preventive measures.preventive measures.

The word Hygiene is derived from the Greek word Hygeia — the goddess of health.

The word Hygiene is derived from the Greek word Hygeia — the goddess of health.

“Prevention is better than cure” is an old saying. Preventive medicine deals with the measures to protect the individuals from the diseases, and to keep them in a state of positive health. For this we have to ensure all the above-mentioned prerequisites required for the maintenance of positive health. The environments must be hygienic, with supply of fresh air, safe potable water and balanced diet.

physical factors

Ecology is constituted by the total environment of man. The environment of modern man is partly natural and

partly man-made.

1. air

social factors

1. customs

2. water

3. food

2. beliefs

3. laws

5. modes of living of human beings

4. peculiarities3. vectors

biological factors

4. buildings

1. pathogens,

2. microorganisms as well as living

beings

4. plants

Environmental SanitationThe word sanitation is derived from the Latin word

Sanitas which means a state of health. Environmental Sanitation means the control of all

those factors in man's surroundings, which cause or may cause adverse effects on his health. The sanitarian directs his efforts towards hygiene of water and food supply, hygienic disposal of human wastes, hygiene of housing and control of vectors and rodents etc.

1. Hygiene as sciences

Hygiene

is a science, which investigates regularities of influence of the environment on the organism of the man and public health with the purpose of the substantiation of the hygienic norms, sanitarian rules and measures, realization of which will ensure optimum conditions for vital activity, improving of health and preventing of diseases.

The following definition now is accepted:

The principal topics of the subject are:

Hygiene of atmospheric airWater supply hygieneHygiene of nutritionOccupational hygieneRadiological hygieneHygiene of children and teenagersHospital hygieneHygiene of extraordinary situationTropical hygiene

Hygiene is a science of preserving and promoting the health of both the individual and the community.

It has many aspects: personal hygiene (proper living habits, cleanliness of body and clothing, healthful diet, a balanced regimen of rest and exercise);

domestic hygiene (sanitary preparation of food, cleanliness, and ventilation of the home);

public hygiene (supervision of water and food supply, containment of communicable disease, disposal of garbage and sewage, control of air and water pollution);

industrial hygiene (measures that minimize occupational disease and accident);

mental hygiene (recognition of mental and emotional factors in healthful living) and so on.

2. The aim and tasks of hygiene

Basic aim of hygiene

Preservation and improving the health of Preservation and improving the health of the man is a basic aim of hygiene.the man is a basic aim of hygiene.

In this occasion the English scientist E.Parce has told, that the hygiene has a great and generous aim: «...To make development of the man «...To make development of the man most perfect, life most intense, wasting least fast, most perfect, life most intense, wasting least fast, and death most remote».and death most remote».

Tasks of hygiene :

1. Study of the

natural and anthropogenesis factors of the environment and social conditions which influence on health of the man.

4. Introduction in practice of public health services and national economy developed hygienic recommendations, rules and norms, check of their effectiveness and perfecting.

5. Prediction of the sanitarian situation for the nearest and remote perspective in view plans of development of the national economy. Definition of appropriate hygienic problems, which implying from prognostic situation and scientific working out these problems.

2. Study regularities of influence the factors and conditions of an environment on an organism of the man or population.

3. Scientific substantiation and working out of the hygienic norms, rules and measures, which help use maximum positively influencing on an organism of the man the factors of an environment and elimination or restriction up to safe levels unfavourable operating ones.

3.Basic methods of hygienic researches

Methods of hygieneMethods of hygiene

2. Methods of studying of environmental influence on human organism and health

1. Methods of environment studying

Methods of sanitary

examination with further sanitary

description

Methods of environment studying

Instrumental and laboratory methods

Geographical

Physical

Sanitary-statistic

chemical

Biological

Methods of experimental investigation

Methods of Studying of Environmental Influence on Human Organism and Health

1.Experiment with models of natural

condition

Methods of natural

observation

1.Clinical

2.Laboratory experiment on animals

3.Laboratory experiment on humans

2. Physiological

3. Biochemical

5. Sanitary-statistic

4. Toxicological

6. Medical-geographical

Hygienic standardization:

Environmental standards are definite ranges of environmental factors which are optimal or the least dangerous for human life and health.

In Ukraine basic objects of hygienic standardization are: MAC – maximum admissible concentration (for chemical

admixtures, dust and other hazards) MAL – maximum admissible level (for physical factors) LD – dose limit (for ionizing radiation) Optimum and admissible parameters of microclimate,

lighting, solar radiation, atmospheric pressure and other natural environmental factors.

Optimum and admissible daily requirements in food and water.

Let's study the methodical scheme of hygienic norms of substantiation using, the example of MAC for some toxic

substance. The first stage is stud physical and chemical properties of the substance, elaboration of methods of quantitative determination of this substance in different subjects, determination of its regimen of action on the human (duration, interruption, changes of intensity), ways of getting into the organism, study migration in different elements of the surrounding, mathematical prediction of duration of existence in different surroundings.

The second stage is study direct influence on the organism. It is started from 'sharp' experiments the main goal of which is getting initial toxicometric data about the substance (determination of LD50, or LC50 threshold of strong action (LIMac) and other. With the knowledge of physical and chemical properties of t he substance, its initial toxicological characteristics and approximate level of MAC can be calculated.

The third stage - is conduction of 'subsharp' experiment during l-2 months for determination of cumulating coefficient and the most vulnerable physiologic systems and organs specification of mechanisms of action and metabolism.

The fourth (basic) stage is carrying out chronic experiment which lasts 4-6 months in the case of modelling of working conditions, 8-12 - communal conditions, 24-36 - in study processes of aging or induction of tumours.

During the experiment integral parameters are studied. They reflect condition of animals, degree of strain of regulative systems, functions and structure of organs which take part in processes of metabolism (activity of enzymes), influence of functional loadings.

Numbers of MACs of toxic chemical substances in the Ukraine are various:

- for the air of working zone - more than 800, - water- 700, - atmosphere air- 200, - food-stuffs - more than 200, - soil - more than 30.

The first group contains factors of anthropogenous origin which are unfavorable for human being, and are not necessary for the normal life activity (dust, noise, vibration, ionizing radiation, etc.). MAC, MAL and LD are those parameters which are set for this group of factors.

The second group contains factors of natural surrounding which are necessary (in certain amount) for normal life activity (food-stuffs, solar radiation, microclimatic factors and others). For this group the following parameters, must be set: optimum, minimum and maximum admissible parameters.

The second group contains factors of natural surrounding which are necessary (in certain amount) for normal life activity (food-stuffs, solar radiation, microclimatic factors and others). For this group the following parameters, must be set: optimum, minimum and maximum admissible parameters.

Basic objects which are under the hygienic norms setting can be divided into two groups.

Basic objects which are under the hygienic norms setting can be divided into two groups.

At last, the modern hygiene should give the most serious attention to preventing of development of some pathological conditions, which are now the basic causes of mortality among the adult population (cardio – vascular diseases, malignant tumours, heavy chronic bronchitis). It is especially necessary, because it is possible to count proved connection of this diseases with unfavourable modifications of an environment.

Max von Pettenkofer, 1818–1901, German chemist and hygienist. He studied medicine at Munich. Pettenkofer is considered a founder of epidemiology and is known for his researches in the ventilation of dwellings, sewage disposal, and the spread of cholera. He developed a method for the quantitative determination of carbon dioxide.

Max von Pettenkofer, 1818–1901, German chemist and hygienist. He studied medicine at Munich. Pettenkofer is considered a founder of epidemiology and is known for his researches in the ventilation of dwellings, sewage disposal, and the spread of cholera. He developed a method for the quantitative determination of carbon dioxide.

Max Rubner (1854-1932) studied with Voit; constructed the first accurate respiration calorimeter in Marburg (1889); professor of hygiene (1891) and professor of physiology (1909) in Berlin; developed concepts of proportionality of body surface areas to energy requirements; collaborated with Heubner to measure energy needs of infants.

Erisman Fedor (Guldreich Friedrich) (1842-1915) is a founder of scientific hygiene in Russia. He’s Swiss by origin. In 1869-1896 he lived in Russia. Professor of Moscow university (since 1882). He had classical traits and guidelines in all principal parts of hygiene. In 1891 he organized the first sanitary-epidemiological station in Russia (now - Moscow Research Institute of Hygiene by Erisman)

Dobroslavin Alexey (1842-1889) is a founder of experimental and military hygiene in Russia. He created the first hygienic laboratory in St.-Petersburg.

Subbotin Viktor (1844 - 1898) was the first Ukrainian professor of hygiene.

In 1871, V.Subbotin was elected an assistant-professor of the Kyiv University and soon appointed a head of the first Department of Hygiene, Medical Police, Medical Geography and Statistics. The works by V. Subbotin were mainly devoted to the problems of general and communal hygiene. Problems of hygiene of hospitals, sanitary protection of water bodies, medical geography occupied the leading place among them.

  

Air is vital to maintain life and

serves to ensure a constant supply of life giving oxygen

to the body through the process of

respiration. One can refuse polluted food and water but

not the polluted air. An unlimited,

relatively clean air is necessary for comfortable and healthful living.

Air is vital to maintain life and

serves to ensure a constant supply of life giving oxygen

to the body through the process of

respiration. One can refuse polluted food and water but

not the polluted air. An unlimited,

relatively clean air is necessary for comfortable and healthful living.

Air is absolutely essential for the maintenance of life. Besides supplying the life giving oxygen, atmospheric conditions and air

serve several useful functions.

Functions of AirFunctions of Air1. It serves to maintain Life through constant oxygen supply.2. It helps in regulation of body temperature; cooling power of the air being an important factor.3. It helps in functioning of sensations like smell and hearing.4. The adverse function is through the polluted air, which be comes a source of spreading various diseases, whether bacterial or otherwise.

Air is absolutely essential for the maintenance of life. Besides supplying the life giving oxygen, atmospheric conditions and air

serve several useful functions.

Functions of AirFunctions of Air1. It serves to maintain Life through constant oxygen supply.2. It helps in regulation of body temperature; cooling power of the air being an important factor.3. It helps in functioning of sensations like smell and hearing.4. The adverse function is through the polluted air, which be comes a source of spreading various diseases, whether bacterial or otherwise.

The atmosphere may be divided into several The atmosphere may be divided into several layerslayers

Gas Fresh airPercent by volume

Nitrogen 78.8 %

Oxygen 20.94 %

Carbon dioxide 0.033 %

Air is a mechanical mixture of gases and not a chemical compound. It is enveloping earth as atmosphere. Pure air has approximtely the following composition:

Natural Sources of Air PollutionNatural Sources of Air PollutionIt is difficult to give a simple definition of It is difficult to give a simple definition of

pollution. The word comes from the Latin pollution. The word comes from the Latin pollutus, pollutus, which means made foul, unclean, or dirty. Some which means made foul, unclean, or dirty. Some authors limit the use of the term to damaging authors limit the use of the term to damaging materials that are released into the environment by materials that are released into the environment by human activities. There are, however, many natural human activities. There are, however, many natural sources of air quality degradation.sources of air quality degradation.

Volcanoes spew out ash, acid mists, hydrogen sulfide, and other toxic gases. Sea spray and decaying vegetation are major sources of reactive sulfur compounds in the air. Forest fires create clouds of smoke that blanket whole continents.

Trees and bushes emit millions of tons of volatile organic compounds (terpenes and isoprenes).Pollen, spores, viruses, bacteria, and other small bits of organic material in the air cause widespread suffering from allergies and airborne infections. Storms in arid regions raise dust clouds that transport millions of tons of soil and can be detected half a world away. Bacterial metabolism of decaying vegetation in swamps and of cellulose in the guts of termites and ruminant animals is responsible for as much as two-thirds of the methane (natural gas) in the air.

Human-caused Air PollutionHuman-caused Air Pollution Primary pollutantsPrimary pollutants are those released are those released

directly into the air in a harmful form. directly into the air in a harmful form.

Secondary pollutantsSecondary pollutants, by contrast, are , by contrast, are modified to a hazardous form after they modified to a hazardous form after they enter the air or are formed by chemical enter the air or are formed by chemical reactions as components of the air mix and reactions as components of the air mix and interact. Solar radiation often provides the interact. Solar radiation often provides the energy for these reactions. Photochemical energy for these reactions. Photochemical oxidants and atmospheric acids formed by oxidants and atmospheric acids formed by these mechanisms are probably the most these mechanisms are probably the most important secondary pollutants in terms of important secondary pollutants in terms of human health and ecosystem damage. human health and ecosystem damage.

Fugitive emissionsFugitive emissions are those that do not are those that do not go through a smokestack. By far the most go through a smokestack. By far the most massive example of this category is dust massive example of this category is dust from soil erosion, strip mining, rock from soil erosion, strip mining, rock crushing, and building construction (and crushing, and building construction (and destruction).destruction).

The most common gaseous pollutants areThe most common gaseous pollutants are

nitrogen oxides

carbon monoxidehydrocarbons

particulates

photochemical oxidants

sulfur dioxide

lead

Indoor Air PollutionIndoor Air Pollution

AsbestosAsbestosVinyl chlorideVinyl chloride

FormaldehydeFormaldehydeSmoking Smoking

radon gasradon gas

The level of risk depends on several factors:•the amount of pollution in the air, •the amount of air we breathe in a given time •our overall health.

Other, less direct ways people are exposed to air pollutants are:

•eating food products contaminated by air toxins that have been deposited where they grow, •drinking water contaminated by air pollutants, •ingesting contaminated soil, and •touching contaminated soil, dust or water.

How does air pollution affect me? Many studies have shown links between pollution and health effects. Increases in air pollution have been linked to decreases in lung function and increases in heart attacks. High levels of air pollution directly affect people with asthma and other types of lung or heart disease. Overall air quality has improved in the last 20 years but urban areas are still a concern. The elderly and children are especially vulnerable to the effects of air pollution.

ILL-EFFECTS OF POLLUTED AIRILL-EFFECTS OF POLLUTED AIRThey are as follows:-They are as follows:- 1.1. Due to physical changeDue to physical changeImmediate effects :Immediate effects : Nausea, vomiting, fever, annoyance, headache etc. Nausea, vomiting, fever, annoyance, headache etc.Late effects :Late effects : Anemia, Tuberculosis, Chronic bronchitis, Primary lung Anemia, Tuberculosis, Chronic bronchitis, Primary lung

cancercancer 2.2. Due to chemical changeDue to chemical change

Pneumoconiosis is the group of diseases which takes place due to Pneumoconiosis is the group of diseases which takes place due to inhalation of suspended dust particles. There is irreversible fibrosis in inhalation of suspended dust particles. There is irreversible fibrosis in lungs.lungs.

Asbestosis, silicosis, Siderosis are example of pneumoconiosis.Asbestosis, silicosis, Siderosis are example of pneumoconiosis. 3.3. On plants and animals:On plants and animals:

Plants are very sensitive to sulphur dioxide, fluorine Plants are very sensitive to sulphur dioxide, fluorine compounds, smoke etc. Spotting and burning of leaves, destruction of compounds, smoke etc. Spotting and burning of leaves, destruction of crops, and retarded growth of plants have been observed due to air crops, and retarded growth of plants have been observed due to air pollution.pollution.

Fluorides are very toxic to animals; catties suffer by eating Fluorides are very toxic to animals; catties suffer by eating foliage contaminated with fluorides.foliage contaminated with fluorides.

4.4. Global effects:Global effects:a - Ozone depletiona - Ozone depletionb - Green house effectb - Green house effectc - Acidic rain c - Acidic rain

a. Ozone Depletiona. Ozone DepletionItroduction Itroduction : Ozone is a gas having formula O3. It is present : Ozone is a gas having formula O3. It is present

at a distance of 15-50 Km from earth. It has encircled the earth like a at a distance of 15-50 Km from earth. It has encircled the earth like a jacket. jacket.

Function : Function : It prevents some wavelengths of ultraviolet It prevents some wavelengths of ultraviolet radiation, which are coming from the sun. radiation, which are coming from the sun. Causes of Ozone depletion Causes of Ozone depletion : : Ozone layer is depleted from chlorofluorocarbons (CFCs). They Ozone layer is depleted from chlorofluorocarbons (CFCs). They cause a chemical interaction with Ozone and so lead to cause a chemical interaction with Ozone and so lead to thinning of ozone layer. Chlorofluorocarbons are present in:thinning of ozone layer. Chlorofluorocarbons are present in:

Aerosol spraysAerosol spraysAir conditionersAir conditionersRefrigeratorsRefrigerators

Health Hazards : Health Hazards : Ultraviolet radiation if comes directly with all Ultraviolet radiation if comes directly with all wavelengths, they cause skin cancer and cataract.wavelengths, they cause skin cancer and cataract.

If there is 1 % fall of ozone, there is 4-6% more chances of If there is 1 % fall of ozone, there is 4-6% more chances of skin cancers, 0.8-1.5% increase in melanomas and 0.2-0.6% increase skin cancers, 0.8-1.5% increase in melanomas and 0.2-0.6% increase in cataract cases.in cataract cases.

Prevention :Prevention :I- Less use of Aerosol sprays (Ozone friendly sprays preferred) I- Less use of Aerosol sprays (Ozone friendly sprays preferred) ii - Prevention of air pollutionii - Prevention of air pollutioniii- Ban on nuclear tests.iii- Ban on nuclear tests.

b- Green House Effect:b- Green House Effect:introductionintroduction: : Green houses are glass huts seen in hilly areas and in the Green houses are glass huts seen in hilly areas and in the agricultural processing areas.agricultural processing areas.

Mechanism Mechanism : : When light falls on any surface which is transparent, some rays are When light falls on any surface which is transparent, some rays are reflected and some are refracted. A process of partial retention of light takes place reflected and some are refracted. A process of partial retention of light takes place in the green house, so temperature in the glass house is increased.in the green house, so temperature in the glass house is increased.

Causes of Green house effectCauses of Green house effect: : The air pollution causes emission of gases likeThe air pollution causes emission of gases likeCOCO22 CH CH44 CO CFC's NO CO CFC's NO22 Chlorine Methyl chloroformChlorine Methyl chloroform

These gases are known as Green house gases. These gases cause partial These gases are known as Green house gases. These gases cause partial retention of light in the air and so temperature of the atmosphere increases.retention of light in the air and so temperature of the atmosphere increases.

Annual Rise in Green House Gases :Annual Rise in Green House Gases :

CO2 -- 0.4 % CHCO2 -- 0.4 % CH44 - 1% CO —0.2% CCl - 1% CO —0.2% CCl44-1% -1% NONO2 2 - 0.25% CFC'S ~ 10% Methyl chloroform - 0.7% .- 0.25% CFC'S ~ 10% Methyl chloroform - 0.7% .

Hazards of Green House Effects:Hazards of Green House Effects: Global warmingGlobal warming Increased evaporation from sea.Increased evaporation from sea. Melting of Ice at poles of earth.Melting of Ice at poles of earth. Increase in sea level.Increase in sea level. Floods.Floods. Disturbance at coastal areas due to increased sea level.Disturbance at coastal areas due to increased sea level.

Prevention:Prevention: Decreased industrialization Decreased industrialization Treatment of Industrial smoke Treatment of Industrial smoke Check unfit automobiles.Check unfit automobiles.

c - Acidic Rainc - Acidic RainCause : SO2 & NO2 are released by products of industries : They are also produced as a result of fuel combustion and organic decomposition. They come in atmosphere and cause rain acidic.

Mechanism: When rainfalls, the water (rain drops) combines with NO2 & SO2 resulting in :

NO2 + H2O → HNO3 SO2 + H2O -» H2SO4

As HNO3 & H2SO4 are acids, they cause acidic rain.

Hazards of Acidic Rain :Hazards of Acidic Rain :.. Discoloration of Discoloration of

houses,houses, Rusting of metals. Rusting of metals. Damage of crops. Damage of crops. Skin cancerSkin cancer Damage to marine lifeDamage to marine life Lead poisoning due Lead poisoning due

to damage to lead to damage to lead pipes.pipes.

Prevention:Prevention: i.i. Treatment of Treatment of

industrial smokeindustrial smoke ii.ii. Increase plant Increase plant

growing i.e. growing i.e. ForestrationForestration

This chemical oxides causes acid rain

This chemical oxides causes acid rain

Acid rain causes damage toAcid rain causes damage toLakes and rivers:Lakes and rivers:

Acid rain causes a lower pH in the lakes and rivers Acid rain causes a lower pH in the lakes and rivers and that effects that fishes can't survive in that and that effects that fishes can't survive in that water and therefore there is a big fish dieing and water and therefore there is a big fish dieing and the long term increases are that the fish the long term increases are that the fish reproducing will stop. reproducing will stop.

Trees:Trees:The consequences are that the trees loose needles The consequences are that the trees loose needles and no new trees can be produced. The acid also and no new trees can be produced. The acid also reacts with many nutrients the trees need, such as reacts with many nutrients the trees need, such as calcium, magnesium and potassium, which starves calcium, magnesium and potassium, which starves the trees. the trees.

People:People:Many toxic metals are held in the groundwater, Many toxic metals are held in the groundwater, lakes and in the soil. In that case the people have to lakes and in the soil. In that case the people have to be careful what they eat and drink because that be careful what they eat and drink because that toxic chemicals cause different deceases like toxic chemicals cause different deceases like cancer, damage on livers, diarrhoea in young cancer, damage on livers, diarrhoea in young children and kidneys.children and kidneys.

Buildings:Buildings:If the toxic chemicals in the rain react with the If the toxic chemicals in the rain react with the material in the stones, like calcium carbonate, the material in the stones, like calcium carbonate, the buildings will be destroyed and dissolved. buildings will be destroyed and dissolved.

Here you can see the damagesHere you can see the damages

AIR POLLUTION CONTROL:AIR POLLUTION CONTROL:They use some directions in prevention of air pollution:They use some directions in prevention of air pollution:

technological methodstechnological methods technical methods (Fabric Filters: Baghouses; Dust Collectors; technical methods (Fabric Filters: Baghouses; Dust Collectors;

Weld Fume Collector; ; ; NOx Control – SNCR; NOx Control Weld Fume Collector; ; ; NOx Control – SNCR; NOx Control – SCR; ;)– SCR; ;)

architecture-planning measuresarchitecture-planning measures administrative measuresadministrative measures

At present the purpose of applying and/or developing a At present the purpose of applying and/or developing a controlcontrol technology is to meet ambient air quality standards and other technology is to meet ambient air quality standards and other source related regulations. A control technology can only be applied to source related regulations. A control technology can only be applied to a controllable source. Therefore, it will be difficult to think of a controllable source. Therefore, it will be difficult to think of

controlling emissions from a volcano.controlling emissions from a volcano.

PURIFICATION OF AIRPURIFICATION OF AIRAir is purified naturally. But due to increased rate of Air is purified naturally. But due to increased rate of

pollution, there are artificial methods also required for air pollution, there are artificial methods also required for air purification. purification.

A. Natural methodsA. Natural methodsB. Artificial methodsB. Artificial methods

A- Natural MethodsA- Natural Methods WINDS: WINDS: Winds take away air from industrial areas to deserts, Winds take away air from industrial areas to deserts,

forests region, from where fresh air comes.forests region, from where fresh air comes.

LARGE SIZE: LARGE SIZE: Air purifies by dilution, as very large area occupied Air purifies by dilution, as very large area occupied by air and as soon as polluted air comes it is diluted.by air and as soon as polluted air comes it is diluted.

SUNLIGHT: SUNLIGHT: Sunlight kills bacteria and neutralizes smell producing Sunlight kills bacteria and neutralizes smell producing substances.substances.

RAIN: RAIN: Rainfall settles down the suspended air particles.Rainfall settles down the suspended air particles.

PLANTS: PLANTS: They purify air by process of photosynthesis. They take They purify air by process of photosynthesis. They take up COup CO22 and give O and give O22, which is used up by human beings. They also , which is used up by human beings. They also lower the temperature.lower the temperature.

B- Artificial MethodsB- Artificial Methods1.1. CONTAINMENT:CONTAINMENT:

It means arresting pollutant air at the source, neutralizing It means arresting pollutant air at the source, neutralizing it and detoxifying it and finally it is released in atmosphere, so it and detoxifying it and finally it is released in atmosphere, so that it is least toxic.that it is least toxic.

2.2. REPLACEMENT:REPLACEMENT:It means either replacement of process (that is causing air It means either replacement of process (that is causing air

pollution) or replacement of substance, (e.g.) Use of electricity in pollution) or replacement of substance, (e.g.) Use of electricity in place of coal is an example of replacement.place of coal is an example of replacement.

3.3. DILUTION:DILUTION:The establishment of "green belts" between industrial and The establishment of "green belts" between industrial and

residential areas is an attempt of dilution.residential areas is an attempt of dilution.4.4. DISINFECTION:DISINFECTION:The methods employed for disinfection areThe methods employed for disinfection are a.a. Ultraviolet radiation: They are used for disinfection in O.T. Ultraviolet radiation: They are used for disinfection in O.T.

and wards.and wards. b.b. Chemical mist: Triethylene glucol vapours are effective Chemical mist: Triethylene glucol vapours are effective

bactericides.bactericides. c.c. Dust control: Application of oil to floors of hospital wards Dust control: Application of oil to floors of hospital wards

reduces bacterial content.reduces bacterial content.

Thank your for attentionThank your for attention!!