Author:Author: Lototska Olena VLototska Olena V..

11

The perspectives of development of preventive medicine field

THE PLANTHE PLAN

1.1. Introduction in hygiene and ecology. Introduction in hygiene and ecology. 2.2. Basic laws of hygiene.Basic laws of hygiene.3.3. Bases of preventive and current sanitary Bases of preventive and current sanitary

supervision. supervision. 4.4. Principles of the hygienical setting of norms. Principles of the hygienical setting of norms. 5.5. Cosmosphere, sun radiation and health.Cosmosphere, sun radiation and health.6.6. Hygienical value of sun radiation, physical Hygienical value of sun radiation, physical

properties and chemical composition of air properties and chemical composition of air environment. environment.

7.7. Hygienical value of constituents of biosphere Hygienical value of constituents of biosphere (atmosphere, hydrosphere, litosphere).(atmosphere, hydrosphere, litosphere).

Introduction

“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.

ProphylaxisProphylaxis is one of the basic principles of is one of the basic principles of public health service. The main duty of the public health service. The main duty of the medical workers is the taking of the disease medical workers is the taking of the disease prevention measures for healthy people and prevention measures for healthy people and exacerbation, complication and relapse exacerbation, complication and relapse prevention for the ill.prevention for the ill.

Prophylaxis means the wide system of Prophylaxis means the wide system of state, public and medical measures for state, public and medical measures for preserving and strengthening people’s preserving and strengthening people’s health, the upbringing of the healthy young health, the upbringing of the healthy young generation, work capacity and people’s generation, work capacity and people’s longevity increasing.longevity increasing.

Prophylaxis is divided into three kinds – Prophylaxis is divided into three kinds – primary, secondary and tertiary in accordance to the primary, secondary and tertiary in accordance to the specific kinds of pathology. specific kinds of pathology.

Primary prophylaxisPrimary prophylaxis includes prophylactic includes prophylactic technologies of preventing disease through technologies of preventing disease through removing risk factors (causes and conditions of its removing risk factors (causes and conditions of its development) and improving general body resistance development) and improving general body resistance to risk factors. to risk factors.

Secondary prophylaxisSecondary prophylaxis includes medico-prophylactic includes medico-prophylactic technologies of revealing a disease, preventing its technologies of revealing a disease, preventing its progress, aggravation and possible complications. progress, aggravation and possible complications.

Tertiary prophylaxisTertiary prophylaxis includes medico-prophylactic includes medico-prophylactic technologies aimed at removing negative aftermaths technologies aimed at removing negative aftermaths of the disease (relapses, complications, temporary of the disease (relapses, complications, temporary and permanent disability, death).and permanent disability, death).

Health Health

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

health of the population

genetic factor

(18-22 %),

genetic factor

(18-22 %),

pollution of an environment (17-20 %)

pollution of an environment (17-20 %)

medical etiological factors

(8 -10 %)

medical etiological factors

(8 -10 %)

  way of life (49-53 %)

  way of life (49-53 %)

To promote and maintain a state of health an To promote and maintain a state of health an

individual needs the following prerequisites:individual needs the following prerequisites: Supply of fresh air

and sunlight Safe and potable

water supply Balanced diet Healthful shelter Adequate clothing Protection from

communicable and other avoidable afflictions

Complete sense of protection and security both socially and economically

hygienic environmental sanitation

A congenial social and cultural atmosphere.

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

PROPHYLACTIC MEDICINE PROPHYLACTIC MEDICINE (HYGIENE)(HYGIENE)

Object of studying: Object of studying: healthy healthy man, and groups of the man, and groups of the

practically healthy peoplepractically healthy people

MEDICAL

Object of studying:Object of studying:

sick mansick man

MediciMedicinene

MediciMedicinene

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

Basic aim of hygiene –

preserving and improving healthpreserving and improving health

Professor Winslow defined aim of hygiene Professor Winslow defined aim of hygiene as "science and art of (as "science and art of (i) preventing diseases, (ii) i) preventing diseases, (ii) prolonging life, and (iii) promoting health and prolonging life, and (iii) promoting health and efficiencyefficiency through organized community effort for through organized community effort for

((a) the sanitation of the environmenta) the sanitation of the environment, ,

(b) the control of communicable diseases,(b) the control of communicable diseases,

((c) the education of the individual or personal c) the education of the individual or personal hygiene,hygiene,

(d) the organization of medical and nursing (d) the organization of medical and nursing services for the early diagnosis and preventive services for the early diagnosis and preventive treatment of disease,treatment of disease, and and

((e) the development of the social machinery to e) the development of the social machinery to ensure everyone a standard of living adequate ensure everyone a standard of living adequate for the maintenance of healthfor the maintenance of health, so organizing , so organizing these benefits as to enable every citizen to these benefits as to enable every citizen to realize birth right of health and longevity".realize birth right of health and longevity".

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);

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

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

Main tasks of hygiene are the Main tasks of hygiene are the following:following:

2. Studying the laws of the impact of environmental factors and conditions on the human body 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.

1. Studying the natural and anthropogenic environmental factors and social conditions affecting the health of a human

4. Practical implementation of developed hygienic recommendations, rules and standards in national economy, controlling and improving their effectiveness.

5. Forecasting the sanitary situation for the nearest and remote future, taking into account plans of the national economy development, proper hygienic problems arising from the forecasted situation, scientific research of such problems.

Basic methods of hygienic researches

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

1. 1. Methods of environment Methods of environment studyingstudying

Methods of Methods of hygienehygiene

Methods of Methods of hygienehygiene

Methods of sanitary

examination with further sanitary

description

Methods of environment Methods of environment studyingstudying

Instrumental and laboratory methods

Geographical

Physical

Sanitary-statistic

chemical

Biological

Methods of experimental investigation

Methods of Studying of Environmental Methods of Studying of Environmental Influence on Human Organism and HealthInfluence 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

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.

Environmental SanitationThe word sanitation is derived from the Latin word Sanitas

which means a state of health.

People in ancient societies were concerned about personal hygiene and sanitation for religious reasons. The Bible contains many rules for cleanliness, and describes public health measures still important today. These include quarantining the sick to prevent the spread of disease and avoiding contact with objects used by sick people.

The Greek physician Hippocrates first made the connection between disease and natural environmental factors in the 4th century bc. His treatise Airs, Waters, and Places described how diseases can result from way of life, climate, impure water, and other environmental factors. For the next 2000 years, it was the most widely used text on public health and epidemiology.

Ancient Romans adopted Greek ideas about public health after colonizing Greece in the 1st century bc. Rome's greatest contributions to public health involved sanitary engineering. They built aqueducts to supply Rome with pure water and a public sewer system to carry away wastes, as well as public baths and hospitals. The Roman government also hired physicians and assigned them to villages to care for the poor.

After the Roman Empire collapsed in ad 476 public health efforts were forgotten and unsanitary conditions returned. Millions of people died when great epidemics of smallpox, leprosy, bubonic plague, tuberculosis, and other diseases swept across Europe in the Middle Ages (5th to 15th centuries ad).

The environments must be hygienic, with supply of fresh air, safe potable water and balanced diet. This aspect of preventive medicine started gaining more importance from 18th century onwards with the discovery of various vaccines and sera for the protection against various diseases like small pox, cholera, plague, whooping cough, tetanus, tuberculosis, poliomyelitis etc.

•Edward Jenner discovered vaccination against small pox in 1796. •The discovery of causative agents of the diseases by Louis Pasteur (1822-1895) and Robert Koch (1843-1910) gave a great fillip to the science of preventive medicine. •Von Behring (1854-1917) brought up the principle of serum treatment and use of anti-sera in various diseases.

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 (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.

physical factors

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

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.

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.

The methodical scheme of hygienic norms of

substantiation using, the example of MAC for some toxic

substance.

The first stage is study 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 purpose 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 the substance, its initial toxicological

characteristics and approximate level of MAC can

be calculated.

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

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

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

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

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

The first law of hygiene

can be formulated as follows: the infringement of level of health of the people (disease, decreasing of the resistance, immunological status, adaptation-compensatory opportunities of organism), caused by physical, chemical, biological and psychogenic etiological factors, can occur only at presence of three driving forces:•source of pollution,•mechanism of its influence or ways of its transference •and human susceptible organism.At the absence of one of these conditions, the disturbances of health will not take place.

The word comes from the Latin pollutus, which means made foul, unclean, or dirty. Some is obvious like smoke which you can see but much of it is not obvious at all. Yet you're eating it and drinking it and breathing it most of the time. And what is worse is that all this muck affects all other life on Earth.

What is pollution?What is pollution?

You can find pollution made You can find pollution made by people just about by people just about everywhere on the planet. everywhere on the planet. Even remote places like the Even remote places like the Arctic are badly polluted by Arctic are badly polluted by nasty chemicals made by nasty chemicals made by people. The polar bears and people. The polar bears and seals there have poisonous seals there have poisonous chemicals made by people in chemicals made by people in their bodies and so do the their bodies and so do the Inuit people who live with Inuit people who live with them. These nasty things kill them. These nasty things kill many animals and make many animals and make others sick -- including others sick -- including penguins in the Antarctic.penguins in the Antarctic.

On a degree of danger distinguish four groups of On a degree of danger distinguish four groups of chemical substances – pollutes:chemical substances – pollutes: I I - especially high toxic (middle death doze -LD- especially high toxic (middle death doze -LD

5о5о - is lower - is lower

than 50 mg/kg of weight of body); than 50 mg/kg of weight of body); II - high toxic (LDII - high toxic (LD

5о5о = 50 - 200 mg/kg); = 50 - 200 mg/kg);

Ш - middle toxic (LDШ - middle toxic (LD5о5о = 200 - 1000 mg/kg); = 200 - 1000 mg/kg);

IV - low toxic (LDIV - low toxic (LD5о5о- more than 1000 mg/kg) - more than 1000 mg/kg)

The concept about first driving force of process of The concept about first driving force of process of change of level of health allows to study laws of change change of level of health allows to study laws of change of polluting substances in an environment, their of polluting substances in an environment, their decomposition and transformation under influence of the decomposition and transformation under influence of the physical and chemical factors of an environment. The physical and chemical factors of an environment. The basic purpose of these measures is the decreasing of basic purpose of these measures is the decreasing of concentration of polluting substances in an environment concentration of polluting substances in an environment up to a level, which is safety for health of the population.up to a level, which is safety for health of the population.

polluting substance

AIR MAN

water

Plants

MAN

Animals

MAN

SOIL

The following ways of toxic, radioactive and biological agents transmission are possible

The following ways of toxic, radioactive and biological agents transmission are possible

polluting substance

polluting substance

Major condition of high stability of the organism to adverse factors of environment is healthy way of life, excluding the using of alcoholic drinks, smoking, other harmful habits, rational nutrition, rational mode of work and rest, observance of rules of personal hygiene, using of wide improving opportunities of physical culture and sports, self preparing.

During the process of live the man allocates in During the process of live the man allocates in environment excrement (faces, urine), which are very environment excrement (faces, urine), which are very dangerous in the epidemic and sanitary attitude. dangerous in the epidemic and sanitary attitude.

Human activities can release substances into Human activities can release substances into the air, water and soil some of which can cause the air, water and soil some of which can cause problems for humans, plants, and animalsproblems for humans, plants, and animals. .

The second law (negative anthropogenic The second law (negative anthropogenic action) - action) - people unfavorably influence on the people unfavorably influence on the environment in connection with their environment in connection with their physiological, domestic and industrial action.physiological, domestic and industrial action.

The second law of hygiene

Traditional forms of pollution includeTraditional forms of pollution include

air pollution, water pollution, and air pollution, water pollution, and radioactive contamination while a broader radioactive contamination while a broader interpretation of the word has led to the interpretation of the word has led to the ideas of ship pollution, light pollution, and ideas of ship pollution, light pollution, and noise pollution.noise pollution.

Serious pollution sources includeSerious pollution sources include chemical chemical plants, plants, oil refineriesoil refineries, , nuclear wastenuclear waste dumps, regular dumps, regular garbage dumps (many toxic substances are illegally garbage dumps (many toxic substances are illegally dumped there), incinerators, dumped there), incinerators, PVCPVC factories, car factories, car factories, plastics factories, and corporate animal factories, plastics factories, and corporate animal farms creating huge amounts of animal waste. farms creating huge amounts of animal waste.

Some sources of pollution, such asSome sources of pollution, such as nuclear powernuclear power plants or plants or oil tankersoil tankers, , can release very can release very severe pollution when accidents occur. Some of the severe pollution when accidents occur. Some of the more common contaminants are more common contaminants are chlorinated hydrocarbonschlorinated hydrocarbons (CFH), (CFH), heavy metalsheavy metals like like leadlead (in lead (in lead paintpaint and until recently in and until recently in gasolinegasoline), ), cadmiumcadmium (in rechargeable (in rechargeable batteriesbatteries), ), chromiumchromium, , zinczinc, , arsenicarsenic and and benzenebenzene..

Common Sources of Primary Pollutants

   Source  PollutantsChemical Formulae

Cars, Trucks, Buses

   Nitrous oxide,      carbon monoxide,      carbon dioxide,     hydrocarbons 

NO2   CO  CO2  CxHy

                                        Industry

  Nitrous oxide,      carbon monoxide,      carbon dioxide,      hydrocarbons   + others 

        NO2           CO          CO2          CxHy

 Aerosol cans    CFCs  

      (chlorofluorocarbons),     hydrocarbons 

  Various

Burning   Coal

  Carbon monoxide,     carbon dioxide     sulfur dioxide  

        CO          CO2          SO2 

There are several main types of pollution and well-known effects of pollution which are commonly discussed. These include •smog, •acid rain,•the greenhouse effect, •and "holes" in the ozone layer.

Each of these problems has serious implications for our health and well-being as well as for the whole environment.

This interaction of gases with water vapour forms sulphuric acid and nitric acids. Eventually these chemicals fall to earth as precipitation, or acid rain. Acid rain pollutants may travel long distances, with winds carrying them thousands of miles before they fall as dew, drizzle, fog, snow or rain.

Acid rain forms when moisture in the air interacts

with nitrogen oxide and sulphur dioxide released

by factories, power plants, and

motor vehicles that burn coal or

oil.

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

Discoloration of houses,Discoloration of 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 to Lead poisoning due to

damage to lead pipes.damage to lead pipes.

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

industrial smokeindustrial smoke ii.ii. Increase plant Increase plant

growing i.e. Forestationgrowing i.e. Forestation

Causes of Green house effect: The air pollution causes emission of gases likeCO2, CH4, CO, CFC's,NO2,,Chlorine, Methyl chloroform

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

Green House Effect:Green House Effect: Green houses are glass

huts seen in hilly areas and in the agricultural processing areas.

Mechanism : 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 in the green house, so temperature in

the glass house is increased.

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

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

Damage to the Damage to the ozoneozone layer is primarily layer is primarily caused by the use of caused by the use of chloroflurocarbons (CFCs). chloroflurocarbons (CFCs). Ozone is a form of oxygen Ozone is a form of oxygen found in the earth's upper found in the earth's upper atmosphere. The thin layer of atmosphere. The thin layer of ozone molecules in the ozone molecules in the atmosphere absorb some of atmosphere absorb some of the sun's ultraviolet (UV) rays the sun's ultraviolet (UV) rays before it reaches the earth's before it reaches the earth's surface, making life on earth surface, making life on earth possible. The depletion of possible. The depletion of ozone is causing higher levels ozone is causing higher levels of UV radiation on earth, of UV radiation on earth, endangering both plants and endangering both plants and animals.animals.

The third law of hygiene (of natural pollution)

The environment is polluted not only under the action of people, but some pollutants come from natural sources.

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.

The fourth law of hygiene – is the law of positive anthropogenic influence on environmental of human

society.

However we must not think, that the environment is absolutely defenseless in front of the activity of the man. The nature has huge resources of self-preservation, self-updating,

self-regulation, maintenance of ecological balance, self-cleaning, but these reserves are not boundless.

The fourth law of hygiene – is the law of positive anthropogenic influence on environmental of human

society.

However we must not think, that the environment is absolutely defenseless in front of the activity of the man. The nature has huge resources of self-preservation, self-updating,

self-regulation, maintenance of ecological balance, self-cleaning, but these reserves are not boundless.

Factors Which Keep the Composition of Air Constant Wind, which dilutes, sweeps away or

aspirates the impurities and gets replaced by pure air.

Rain, which washes the air and removes gases as well as suspended impurities.

Oxygen and ozone, which oxidise the organic matter present in the air.

Plants absorb CO2 and give off oxygen in sunlight. During sunlight, chlorophyll present in green leaves of the plants absorbs carbon from carbon dioxide of the atmosphere and gives off free oxygen, but at night this process gets reversed.

Sun affects the temperature, pressure and volume of air. Thus heating of air during the day and its cooling at night brings about the air movements.

Changing weather and other climatic and meteorological factors affect the direction and velocity of air movements over vast a tomospheric areas.

The fifth law of hygiene is the law of inevitable negative influence of the muddy environment on health of the

population.

People also become ill through exposure to hazards in the environment. Many diseases are linked to

environmental problems such as polluted drinking water, poor waste disposal and air and exposure to

mosquitoes and other carriers of disease.

The fifth law of hygiene is the law of inevitable negative influence of the muddy environment on health of the

population.

People also become ill through exposure to hazards in the environment. Many diseases are linked to

environmental problems such as polluted drinking water, poor waste disposal and air and exposure to

mosquitoes and other carriers of disease.

The fifth law of hygiene

Air pollution can affect our health Air pollution can affect our health in many ways with both short-in many ways with both short-term and long-term effects. term and long-term effects. Different groups of individuals Different groups of individuals are affected by air pollution in are affected by air pollution in different ways. Some individuals different ways. Some individuals are much more sensitive to are much more sensitive to pollutants than are others. pollutants than are others. Young children and elderly Young children and elderly people often suffer more from people often suffer more from the effects of air pollution. the effects of air pollution.

People with health problems such People with health problems such as asthma, heart and lung as asthma, heart and lung disease may also suffer more disease may also suffer more when the air is polluted.when the air is polluted.

Effects of Air Pollution

Examples of short-term effects include irritation to the eyes, nose and throat, and upper respiratory infections such as bronchitis and pneumonia. Other symptoms can include headaches, nausea, and allergic reactions. Short-term air pollution can aggravate the medical conditions of individuals with asthma and emphysema. In the great "Smog Disaster" in London in 1952, four thousand people died in a few days due to the high concentrations of pollution.

Long-term health effects can include chronic respiratory disease, lung cancer, heart disease, and even damage to the brain, nerves, liver, or kidneys. Continual exposure to air pollution affects the lungs of growing children and may aggravate or complicate medical conditions in the elderly. It is estimated that half a million people die prematurely every year in the United States as a result of smoking cigarettes.

Air Pollutant Health Effects

Carbon Monoxide (CO)

Colourless and odourless gas.  Reacts with haemoglobin in preference of oxygen. This reduces the amount of oxygen being carried around the body and can result in suffocation. Fortunately, this reaction is slow and requires very high concentrations before advserse effects are felt.

Nitrogen Dioxide (NO2)

Brown poisonous gas.  Effects trachea and lungs causing respiratory problems.

Ozone (O3)

Colourless gas, slightly sweet odour at low concentrations.  Causes eye irritations at concentration of 0.3ppm and respiratory problems at higher concentrations

PAN gas Effects eyes, nasal passages and respiratry system.

The sixth law of hygiene is the law of positive influence of the factors of a natural environment on health of the population.

The natural factors of the environment (air, water, good-quality food) have a positive influence on people’s health. They provide preservation and strengthening of the human health

The sixth law of hygiene

Good nutrition is a basic component of health. It is essential for the attainment of normal growth and development. Not only physical growth and development, but also the intellectual development, learning and behavior are affected by malnutrition. In short, nutrition affects human health from birth till death.

Good nutrition is a basic component of health. It is essential for the attainment of normal growth and development. Not only physical growth and development, but also the intellectual development, learning and behavior are affected by malnutrition. In short, nutrition affects human health from birth till death.

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.

Functions 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.

Inspired air

Expired air

Oxygen 20.95 % 16.50 %

Nitrogen 79.02 % 79.06%

C02 0.04% 4.44%

Water vapours

Varies Saturated

Temperature

Varies As of body temperature

Impurities due to RespirationImpurities due to Respiration

The sun is a source of electromagnetic energy including radio waves, infrared, visible light, ultraviolet, x-rays, gamma rays, and cosmic rays. Each band has its own characteristic wavelengths and properties as a result of wavelength.Visible light is "visible" because its wavelengths can be detected as various colors by the human eye. Ultraviolet, although invisible, also has various wavelengths and properties.

. Category

Wavelength

(nanometres, nm)

Relevance to life on earth

Ultraviolet (UV)

100-400

Causes short- and long- radiation term damage to exposed living matter, particularly, in humans, sunburn, photoageing and cancer of the skin

Visible light

400-800Allows us to see; enables plants to create food molecules; drives human biorhythms; lifts human mood

Infrared radiation

800-17,000

Warms our bodies

The light you can see has a wavelength of 400-760 (nm). UV raysregion А – long-wave ultraviolet radiation: = 315-400 nm;region В – middle-wave ultraviolet radiation: = 280-315 nm;region С – short-wave ultraviolet radiation: = 120-280 nm.

The solar ultraviolet radiation wave lenght less then 290 nm is completely absorbed by oxygen and ozone of the upper atmosphere. Atmospheric pollution by factory waste helps the ozone layer destruction resulting in appearance of “ozone holes”. The shortest and the most harmful UV waves reach the earth surface through these “ozone holes”.

Positive effects

UV rays are necessary for our body to produce vitamin D, a substance that helps strengthen bones and safeguards against diseases such as Rickets. Some scientists have shown that Vitamin D lowers the risk of getting some kinds of internal cancer, like colon cancer.UV light is also used as a therapy for psoriasis, a condition in which the skin sheds its cells too quickly, resulting in itchy, scaly patches on various parts of the body. When exposed to ultraviolet rays, the growth of the skin cells is slowed, relieving the symptoms.UV rays are also used in various commercial functions, such as disinfecting fish tanks and sterilizing medical equipment. Animal life makes their own use of these wavelengths too—certain animals can actually see ultraviolet light, and use it to their advantage. Bees use the reflection of UV off of flower petals to guide their pollen collecting. 

2.1.

Is ultraviolet light harmful?The difference has to do with the ability of UV rays to penetrate body surfaces.UV-A is also known as "blacklight" and is generally harmless. It results in skin tanning and is used in medicine to treat certain skin disorders. UV-B has a very high penetrating ability and prolonged exposure is responsible for some types of skin cancer, skin aging, and cataracts (clouding of the lens of the eye). UV-C has extremely low penetrating ability and is nearly completely absorbed by the outer, dead layer of skin where it does little harm. It does reach the most superficial layer of the eye where overexposure can cause redddening and painful but temporary irritation, but it cannot penetrate to the lens of the eye and cannot cause cataracts. UV-C is also known as "germicidal UV."

Over the years, researchers of human comfort have established the variables that affect a human's thermal sensations and they have

established the ranges of these variables within which the average person is comfortable.

Six primary comfort variables

These "comfort" variables include air temperature, relative humidity, air motion, and mean radiant temperature. The mean radiant temperature is the average temperature of all of the surfaces that surround the person in question. These four variables are called the "environmental variables" because they represent the environment surrounding the body.

A second set of variables, called the "personal" variables, are controlled by the individual. The two are the clothing insulation value, termed the "clo" value, and the metabolism rate.

Thermoregulation of human organism on 85 % is realized through the skin. The most of the heat (45 %) organism loses by the emitted radiation, 30 % by convection and conduction, 10 % by evaporation (perspiration).

Heat Generated

Body

Skin

Sweat

Clothing

Exposed surface

Respiration

Evaporative heat loss

Surface in environment

Radiation

Convection

Sensible heat loss from the skin

High humidity of air sharply decreases heat loss by perspiration. Heat loss by conduction first of all depends on temperature of subjects contacting with body, and by convection (circulation) - also on speed of air moving.

Heat loss by convection is proportional to square root of speed of air moving (√V). In air temperature 33°C heat loss by convection stops, and in further increase of temperature body heating takes place. If temperature of environment is equal to body temperature heat loss by conduction and radiation stops. Thus, in conditions of high temperature and humidity in absence of air moving adaptive possibilities of thermoregulation are sharply narrowed and tensed.

TemperatureTemperature is a measure of the amount of heat (average molecular kinetic energy) in a material, such as air. Temperature is the average amount of “moving” energy contained by particles moving around in the atmosphere.

Temperature is measured with thermometers that may be calibrated to a variety of temperature scales. The basic unit of temperature (symbol: T ) in the International System of Units (SI) is the kelvin (Symbol: K). In most of the world, the degree Celsius scale is used for most temperature measuring purposes.

Many physical properties of materials including the phase, density, solubility, vapor pressure, and electrical conductivity depend on the temperature. Temperature also plays an important role in determining the rate and extent to which chemical reactions occur. This is one reason why the human body has several elaborate mechanisms for maintaining the temperature at 37 °C, since temperatures only a few degrees higher can result in harmful reactions with serious consequences. Temperature also controls the type and quantity of thermal radiation emitted from a surface.

Air PressureAir pressure is the force of air pushing down on earth. Air pressure due to weather is also known as Atmospheric Pressure. Air pressure is the result of Earth’s gravity pulling on the atmosphere.

                           A barometer is used to measure air pressure. The average pressure exerted by the atmosphere on sea level is 1 bar. The millibar (one-thousandth of a bar) is the unit commonly used to report air pressure.

Generally, air pressure decreases with higher altitude. Pretend air pressure is like a column of air reaching into the sky. The higher up the land is, the shorter the column of air is on top of it. A shorter column has less mass and weighs less. As such, there is less air on top of mountains pushing down than there is down in a valley.

Water vapor in the air is called humidity. Hygrometers are used to measure humidity. Relative humidity is the amount of water vapor in a volume of air compared to the maximum amount of vapor that volume of air could possibly hold. Relative humidity is measured by a psychrometer and reported as a percentage.                            

Wind is the movement of air from a location of high pressure to a location of low pressure as pressure equalizes. Wind is described in terms of its direction and speed.

Wind vanes are used to indicate wind direction. Wind vanes point into the wind, meaning they point in the direction from which the wind is coming. Winds are named for the direction from which they are coming.

Anemometers measure wind speed. Wind speed is reported in kilometers or miles per hour (km/h or mph), or in centimeters or meters per second (cm/s or m/s).