Foundations in Medicine

بسم الله الرحمن الرحيم

Foundations in Medicine Lec -6-

Air Pollution

Air pollution is one of the present -day health problems world wide.
Air pollution is an inescapable consequence of the presence of man and his activities.

Pollution

Environmental pollution can be subdivided into:- 1.Air Pollution. 2.Water pollution. 3.Soil Pollution.

Air pollution:

The presence in the surrounding atmosphere of substances ,generated by the activities of man , in concentrations that interfere with human health,safety or comfort,or injurious to vegetation and animals and other environmental media,resulting in chemicals entering the food chain or being present in drinking water and therapy constituting additional source of human exposure.

1. Automobiles:

They emit hydrocarbons ,carbon monoxide , lead,nitrogen oxides and particulate matter.
In sun light, certain of these hydrocarbons and oxides of nitrogen may be converted into photochemical pollutants of oxidizing nature.


The direct effect of air pollution on plants ,animals and soil can influence the structure and function of ecosystems ,including self regulation ability ,therapy affecting the quality of life.

Sources of Air Pollution:

They emit large amounts of pollutants into the atmosphere.
Combustion of fuel produces smoke,sulphur dioxide,nitrogen fluoride,hydrochloric acid and organic halides.
Many industries discharge carbon monoxide, carbon dioxide ,ozone,hydrogen sulphide and sulphur dioxide.

Diesel engines are capable of emitting black smoke and malodorous fumes.

2.Industries :


Domestic combustion of coal,wood or oil is a major source of smoke,dust,sulphur oxide and nitrogen oxides.
4.Tobacco Smoke:
The most direct and important source of air pollution affecting people health.
5.Miscellaneous
(Burning refuse ,incinerators ,pesticide,natural sources e.g. wind born dust,fungi,bacteria)and nuclear energy program.

3.Domestic Sources:

Meteorological factors:-


Although the Earth’s atmosphere extends to several layers above the surface,man is most directly concerned with only (8-10)km of atmosphere.The level of atmospheric pollution depends upon meteorological factors e.g. topography , air movement and climate.Winds help in the dispersal and dilution of pollutants.


The vertical diffusion of pollutants depends upon the temperature gradient .Rapid cooling of lower layers of air little vertical motion and the pollutants and water vapors remain trapped at the lower level and the result is “smog”.



Temperature inversion which is more frequent in winter months is a threat to human health.


It contributes to acute respiratory infections in young children,chronic lung disease and cancer in adults,and adverse pregnancy out comes (such as still births) for pregnant exposed.

Indoor Air Pollution:

It is one of the most critical global environmental problems that exposes people to important air pollutants than does pollution in outdoor air.

A.Health Aspects :

Usually the most common and include chronic bronchitis,lung cancer,bronchial asthoma, emphysema and respiratory allergies.

Effects of Air Pollution:

1.Immediate effects on respiratory tract resulting in acute bronchitis, dyspnea , suffocation and death. 2.Delayed Effects



Precise estimates of the risk of air pollution to health are difficult to quantify because:
A. Difficult to estimate degree of exposure of individuals.
B.The influence of possible confounding variables such as smoking, nutrition, occupation and climate.


Lead poisons is particularly dangerous to children developing brain and nervous system I impaired neuro psychological development ( IQ),poor school performance and behavioral difficulties.


1.Destruction of plant and animal life . 2.Corrosion of metals. 3.Damage of buildings. 4.Cost of cleaning and maintenance. 5.Reduces visibility in towns . 6.Soil and damage clothing.


Sudden increase in air pollution often associated with immediate increase in morbidity and mortality.

B.Social And Economic Aspects:

1.Natural impurities which are not essentially dangerous.
It include dissolved gasses e.g. nitrogen ,carbon dioxide, hydrogen sulphide..etc,and dissolved minerals e.g. salts of calcium, magnesium, sodium..etc,and suspended impurities e.g. clay,sand and mud.
It is derived from the atmosphere ,catchment area and the soil.

Water Pollution :

Pure uncontaminated water doesn't occur in nature . Impurities include:


A.Sewage.B. Industrial and trade wastes.C. Agricultural pollutants.D.Physical pollutants.
Even if water source and treatment are of high standard,water pollution may still occur because of:

2.Man-made impurities:

It is caused by human activity -urbanization and industrialization. Sources of it are:-

Water -related diseases:

A.Biological (Water -borne diseases).1.Those caused by presence of infective agent:a.Viral hepatitis,poliomyelitis ,rota viral diarrhea. b.Bacterial typhoid and paratyphoid fever,bacillary dysentry .

1.Corrosion of pipe lines.2.Leaky joints and cross connections between water supply pipes and sewage drainage pipes.



Thus surveillance has to be exercised at every point in the distribution system to ensure supply of safe water to the consumer.

a.Snail Schistosomiasisb.Cyclops Guinea worm ,fish tape worm.

B.Chemical Pollutants diseases.
1.By direct effect on man. 2.Indirectly through accumulating in aquatic life used as human food e.g. fish.


c.Protozoal amoebiasis,giardiasis.d.Helminthic worm infestations.e.Leptospiral Weils disease.

2.Those due to presence of aquatic host:

2.Cyanosis in infants. High nitrate content methaemoglobinaemia. 3.Cardiovascular diseases. Hard water is protective. 4.Disease due to inadequate water supply e.g.shigellosis,trachoma,conjunctivitis,scabes. 5.Diseases related to disease carrying insects breeding in or near water e.g. malaria ,trypansomiasis.

C.Water associated illnesses:

Caries 1.Dental health mottling of dental enamel

Soil pollution :

Soil pollutants sources are:- 1.Lead from fuel. 2.Insecticides e.g. DDT,Arsenic,Mercury. 3.Radioactive by products . 4.Various parasites and pathogens e.g .anthrax spore can survive up to 40 years.

Scope of environmental health program.

1.Planning+Design+Construction+Maintenance of safe water supply. 2.Safe methods of collection and disposal of excreta. 3.Control of insects,rodents and animal reservoirs. 4.Protect water sources. 5.Proper collection and disposal of refuse. 6.Food and milk sanitation. 7.Public health supervision.


8.Occupational hazards control.9.Environmental catastrophes control.10.Industrial pollution control.11.Control transport aspects.

The End