MATTER
SECTION 1: HEALTH AND THE ENVIRONMENT
Objectives
• Define the environment
• Explain the components of the environment
• Describe the effects of environmental factors on health
Environmental health-: is the branch of public health that is concerned with all
aspects of the
natural and built environment that may affect human health.
Since the environment comprises all things that make up your surroundings, environmental
health, therefore, describes the aspects of health related to or emanating from your interaction
with the environment.
Environmental Components and their Effect on Health
The following factors can have an effect on health:
• Biological environment
• Physical environment
• Socio-cultural environment
• Economic and political environment
Components of the environment
1. Biological Environment
The biological component of the environment is made up of living things, which include
plants,
people and animals.
Plants: Vegetation prevents soil erosion and also protects our water sources. Trees act as
windbreakers, provide firewood, charcoal, timber and paper among others. They also
influence
weather patterns. Flowers are a natural beauty and are often used for decoration. Plants
provide
vegetables, fruits, tubers and seeds as food. A number of plants are used as herbal medicine
for
the treatment of various diseases, for example, the Neem tree locally known as muarobaine,
is
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used for the treatment of malaria, among many other diseases. Garlic is used to treat
hypertension. The aloe vera plant is used for prevention of cancer of the stomach and healing
of
wounds.
On the other hand, some plants may adversely affect health. Occasionally, people react to
pollen
from blooming plants and may develop hay fever or asthma. Ingesting or touching some
poisonous plants may have devastating effects.
People: Human beings and their activities can be a big source of infection. For example,
overcrowding and slum settlements brought about by urbanisation, can promote the
transmission
of diseases, especially those diseases that are spread through droplets and contact. Explosions
from quarries produce a lot of dust, which causes respiratory and eye problems. When it
rains,
these quarries collect water and become breeding sites for mosquitoes and risky places for
, children. The felling of trees provides firewood and charcoal but, at the same time, it destroys
the
water sources. Cultivating along riverbanks may contaminate the water supply through
seepage
of the fertilizers and pesticides used on the crops. Overgrazing causes soil erosion, destroys
vegetation and contaminates water sources.
Animals: Domestic animals such as cattle, sheep, goats and poultry provide meat, milk
and eggs
for consumption. Some of them supply hides and wool for commercial purposes. They also
provide manure, which is used to increase food produce. Wildlife is often a tourist attraction
and
acts as a source of income for our country.
Cats and dogs are kept as pets, but they can also transmit diseases such as cat scratch fever
and
rabies, respectively. Other hazards include snakebites, which can be fatal and insect bites,
which
may act as vectors of various diseases. For example, mosquitoes are vectors of malaria,
yellow
fever and filariasis. Houseflies are vectors of dysentery and other diarrhoeal diseases.
Bacteria,
rickettsia and fungi are also part of the biological environment and are disease-causing
organisms
in man.
2. Physical Environment
The physical components of the environment are divided into geographical and man-made
components.
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Geographical Components: Land is used for settlements. When the land is fertile
and well
used, it provides enough food for consumption. On the other hand, when the land is infertile,
the
food supply will be inadequate, resulting into nutritional problems. The type of soil,
climate
and altitude determine the type of crops that can be grown in a specific area. Some
crops will do
well in a hot climate, others will not. For example, tea, peas and pyrethrum thrive in cool
climates. However, cold climates encourage respiratory diseases and joint problems such as
arthritis. In hot climates, most legumes and fruits such as oranges and mangoes do well.
Diseases
associated with hot climates include malaria. Snakes are also common in hot areas and their
bites can be fatal. Some disease outbreaks occur during the rainy season, for example,
cholera,
typhoid and malaria. Similarly, during dry seasons there may be a shortage of food leading to
malnutrition. Persistent crop failure will lead to food insecurity and famine. Each type of
climate
has its own pattern of vegetation and animals to control. Man has to adjust to the animals and
the
vegetation since they affect health. Additionally, to adjust to the different temperatures man
has
SECTION 1: HEALTH AND THE ENVIRONMENT
Objectives
• Define the environment
• Explain the components of the environment
• Describe the effects of environmental factors on health
Environmental health-: is the branch of public health that is concerned with all
aspects of the
natural and built environment that may affect human health.
Since the environment comprises all things that make up your surroundings, environmental
health, therefore, describes the aspects of health related to or emanating from your interaction
with the environment.
Environmental Components and their Effect on Health
The following factors can have an effect on health:
• Biological environment
• Physical environment
• Socio-cultural environment
• Economic and political environment
Components of the environment
1. Biological Environment
The biological component of the environment is made up of living things, which include
plants,
people and animals.
Plants: Vegetation prevents soil erosion and also protects our water sources. Trees act as
windbreakers, provide firewood, charcoal, timber and paper among others. They also
influence
weather patterns. Flowers are a natural beauty and are often used for decoration. Plants
provide
vegetables, fruits, tubers and seeds as food. A number of plants are used as herbal medicine
for
the treatment of various diseases, for example, the Neem tree locally known as muarobaine,
is
4
Downloaded by timothy kiburu () lOMoARcPSD|13079919
used for the treatment of malaria, among many other diseases. Garlic is used to treat
hypertension. The aloe vera plant is used for prevention of cancer of the stomach and healing
of
wounds.
On the other hand, some plants may adversely affect health. Occasionally, people react to
pollen
from blooming plants and may develop hay fever or asthma. Ingesting or touching some
poisonous plants may have devastating effects.
People: Human beings and their activities can be a big source of infection. For example,
overcrowding and slum settlements brought about by urbanisation, can promote the
transmission
of diseases, especially those diseases that are spread through droplets and contact. Explosions
from quarries produce a lot of dust, which causes respiratory and eye problems. When it
rains,
these quarries collect water and become breeding sites for mosquitoes and risky places for
, children. The felling of trees provides firewood and charcoal but, at the same time, it destroys
the
water sources. Cultivating along riverbanks may contaminate the water supply through
seepage
of the fertilizers and pesticides used on the crops. Overgrazing causes soil erosion, destroys
vegetation and contaminates water sources.
Animals: Domestic animals such as cattle, sheep, goats and poultry provide meat, milk
and eggs
for consumption. Some of them supply hides and wool for commercial purposes. They also
provide manure, which is used to increase food produce. Wildlife is often a tourist attraction
and
acts as a source of income for our country.
Cats and dogs are kept as pets, but they can also transmit diseases such as cat scratch fever
and
rabies, respectively. Other hazards include snakebites, which can be fatal and insect bites,
which
may act as vectors of various diseases. For example, mosquitoes are vectors of malaria,
yellow
fever and filariasis. Houseflies are vectors of dysentery and other diarrhoeal diseases.
Bacteria,
rickettsia and fungi are also part of the biological environment and are disease-causing
organisms
in man.
2. Physical Environment
The physical components of the environment are divided into geographical and man-made
components.
5
Downloaded by timothy kiburu () lOMoARcPSD|13079919
Geographical Components: Land is used for settlements. When the land is fertile
and well
used, it provides enough food for consumption. On the other hand, when the land is infertile,
the
food supply will be inadequate, resulting into nutritional problems. The type of soil,
climate
and altitude determine the type of crops that can be grown in a specific area. Some
crops will do
well in a hot climate, others will not. For example, tea, peas and pyrethrum thrive in cool
climates. However, cold climates encourage respiratory diseases and joint problems such as
arthritis. In hot climates, most legumes and fruits such as oranges and mangoes do well.
Diseases
associated with hot climates include malaria. Snakes are also common in hot areas and their
bites can be fatal. Some disease outbreaks occur during the rainy season, for example,
cholera,
typhoid and malaria. Similarly, during dry seasons there may be a shortage of food leading to
malnutrition. Persistent crop failure will lead to food insecurity and famine. Each type of
climate
has its own pattern of vegetation and animals to control. Man has to adjust to the animals and
the
vegetation since they affect health. Additionally, to adjust to the different temperatures man
has
