INTRODUCTION TO

ENVIRONMENTAL HEALTH
By: Gutama H.

May, 2022

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Learning Objectives
 Define basic terms
 Historical background of Environmental health
 Explain the basic relationship between environment
and health
 Explain why Environmental health matter?
 Explain determinants of health
 Explain the scope of environmental health
 Explain the role of environmental health

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Definitions of terms

What is health???

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 Definition: ‘Health …’
• Is a state of complete physical, mental and social well-being
and not merely the absence of disease or infirmity’(WHO,
1948)

• ‘Health is only possible where:

 Resources are available to meet human needs and
 The living and working environment is protected from life-
threatening and health threatening pollutants, pathogens
and physical hazards’(WHO, 1992a)

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 Definition: ‘Environment’
• Literary environment means the surrounding external
conditions influencing development or growth of people,
animal or plants; living or working conditions etc.
• is the sum of all external conditions and influences that
affect the life and development of an organism, human
behavior or society.
• It can be divided into physical, biological, social, cultural
any or all of which can influence health status in
populations.’ (WHO, 1995)

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 Introduction…
 The environment consists of four segments
1. Atmosphere: - implies the protective blanket of gases,
surrounding the earth

o It absorbs
 most of the cosmic rays from outer space and
 a major portion of the electromagnetic radiation from the sun and
transmits only here visible ultraviolet, and radio waves

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 Introduction…
2. Hydrosphere: comprises all types of water resources oceans,
seas, lakes, rivers, streams, reservoir, polar icecaps, glaciers, and
ground water

3. Lithosphere: is the outer mantle of the solid earth which

consists of minerals occurring in the earth’s crusts

4. Biosphere: indicates the realm of living organisms and their

interactions with the rest environment

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 Definition: ‘Environmental Health’

• Comprises those aspects of human health, including

quality of life, that are determined by physical,
biological, social and psychosocial factors in the
environment

• It
also, refers to the theory and practice of assessing,
correcting, controlling, and preventing those factors in
the environment that can potentially affect the health of
present and future generations’ (WHO, 1993a)

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 Definition: ‘Sanitation’

Sanitation: (derived from the Latin word “Sanitas”,

meaning health); is the establishment of environmental
conditions favorable to health
• It is the prevention of diseases by eliminating or controlling
the environmental factors which form links in the chain of
disease transmission

Public Health: is “the science and the art of preventing

diseases, prolonging life, and promoting health through
organized efforts of society” (WHO)
It is an organized effort carried out for the benefit of
community
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Environmental health

Public Health
Occupational Health

Family Health

Personal Health

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Contamination:
is the presence of an infection agent on a body surface; also
on/in clothes, bedding, toys, surgical instruments or
dressings, including water and food

Pollution:
the undesirable change in the physical, chemical, or
biological characteristics of air, land and water that may or
will harmfully affect human life or that of other desirable
species, industrial processes, living conditions, and cultural
assets: or that may or will waste or deteriorate raw material
resources

Background level/concentration 11
 Definition: ‘Health Effect’
• Is the specific damage to health that an environmental
hazard can cause to an individual person
• Often the same hazard can cause a range of different
effects of different severity.’ (Yassi et al., 2001)

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Historical background of Environmental health

Reading assignment

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Human-environment interaction outcomes

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Human-environment interaction outcomes
Human ecology is the study of the
interactions between humans
With one another

with other living things, and

with their environment in general

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 Human-environment interaction outcomes...

Life sustaining natural

resources:
Air
Water
Food
Energy
Wastes produced
Life vities

The natural ecological

act

• liquid
i
&E

system:
con

• solid
- received and
om

• gaseous assimilated
ic

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 Human-environment interaction outcomes...
The system has been ever active by :
Dispersing gaseous wastes
Diluting animal wastes washed into streams or rivers
Converting organic wastes into humus to support the future
population
ASSIMILATIVE CAPACITY???
☞ This means that:
 for every natural act of pollution or/and
 for every incident that eroded the quality of the immediate
or local environment
there were a natural mechanisms that restored the
quality
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 Human-environment interaction outcomes...

However,
 In recent years, this natural
mechanism has begun to show
sign of stress, primarily because
of man’s unfriendly interaction
with the environment

 natural and manufactured

wastes generated are released into
the biosphere have upset the
natural equilibrium
-

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Does Environmental health Matters?

why?

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 Introduction…
 The issue of environmental health is now a global matter under
the guidance of the UN through the WHO
 Universal human rights:
“All people have the right to a standard of living adequate for
health and well being of themselves and their family, including
food, clothing, housing, healthcare, and the necessary social
services”
 The significance of hygiene and environmental health is
recognized in the UNs’ MDGs and SDGs

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 Introduction…
 The Ethiopian National Health policy considers that hygiene and
environmental health is one of the cornerstones of the strategy
for the promotion of health and wellbeing
The Ethiopian Constitution states that
‘All persons have the right to a clean and healthy
environment’ (Article 44/1).
All Ethiopians should have ‘access to clean water, housing
and food’ (Article 90/1).

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I. Lack of access to clean water and sanitation
According to the Centers for Disease Control and Prevention;
• An estimated 780 million people worldwide don’t have access
to safe drinking water, and a jaw-dropping 2.5 billion (or
roughly a third of Earth’s population) lack adequate sanitation
services like clean bathrooms
• The impact of this is staggering
• An estimated 2,200 children die every day worldwide of
diarrheal diseases linked to improper water and sanitation

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 II. Indoor air pollution
• Majority of the population especially in the continents of
Africa, Asia, Latina America use biomass & fossil fuels like
wood, coal… in an open air or poorly constructed oven…
emission & exposure to smoke high in particulate matter, &
gasses like CO, SO2, NO2
• Women, children & z elderly are venerable population

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III. Vector born diseases

• Malaria
• Dengue and dengue hemorrhagic fever
• Filariasis
• Yellow fever (viral)
• Human African trypanosomiasis

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 IV. Environmental health and poverty

• Poor people’s live in areas with the worst

environmental conditions
• The burden of environmental disease falls more
harshly on the poor…they have lower resistance to
infection
• Poverty--- disease---loss of income---loss of jobs

Health is both a precondition for and

product of economic development

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 V. Other Global problems
• Ozone depletion has raised the risk of skin cancer;
• Loss of biodiversity has raised the need of basified in many
developing countries;
• Global climate change has become a concern in the world:

• Deforestation, draught, earthquakes, hurricanes (a storm

with a violent wind e.g. Suname) etc. are wiping out the lives
of many people every year;
• A quarter of all irrigated land suffers from soil Stalinization

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Physical/environmental factors

Social and cultural factors

Individual behaviors

Biological factors

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 Physical /Environmental factors
i. Climate
Tropical countries
• Warm, humid temperature, prevalence of rain
• Parasitic and infectious diseases are leading community
health problems

Temperate climate
• Fewer parasitic andinfectious disease and a more than
adequate food supply, chronic non-communicable
diseases are common problems

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ii. Production and use of non-renewable natural resource

• Example fossil
fuels
• Non- renewable because it takes billions of years to
produce them when compared with the rate of
consumption

• Theburning of fossil fuels produce 21.3 billion tones of

CO2/year but only half of which is absorbed by natural
process. i.e. 10.65 billion tones is released to the
atmosphere per year

• Thisgas is responsible for the Global temperature

increment

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One of the five deadly effects of global worming is the spread
of diseases
Changes in temperature will affect vector development,
reproduction, behavior and survival rates
Temperature can also affect pathogen development
within vectors
Precipitation can influence the availability of breeding
sites, and
Climatic variables can affect the distribution and
abundance of their vertebrate host species

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iii. Population Growth
• As population and demand for natural resources continue
to grow, environmental limits will become increasingly
apparent
• As we humans exploit nature to meet present needs, we
are destroying resources needed for the future

iv. Industrial development

• Positive impact
Added resources to the community
• Negative impact
Environmental pollution
Occupational illnesses

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 Social and cultural factors
 Arise from the interaction of individuals or groups within
the community
 Prejudice of one specific ethnic group against the other
can result in acts of violence and crime (our country)
 Some limit the type of
medical treatment their
members may receive (contraceptive)
 Some don’t permit immunization, HIV/AIDS
medications, Some never donate blood to the needy
ones, etc.

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i. Social norms
Example
• Alcohol consumption of college students; the
normal expectation seems to be fun.
• Smoking

ii. Socioeconomic status

• low socioeconomic status
Have the poorest health and the most difficulty in
gaining access to health care
• High socioeconomic status
Have family doctors

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 Individual behavior

Examples
• If each occupant wear a safety belt, …
• If an individual is immunized against a certain disease ,
the lower the disease will be spread and the fewer
people will be exposed
• Personalchoices, social and physical environment can
shape individuals behavior
Biological factors
• Individuals genetic makeup
• Family history which may suggest risk for a disease (ex.
DM, Cancer….)
• Physical and mental health problems acquired during life
Aging (stroke) 36
 SCOPE OF
ENVIRONMENTAL HEALTH

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 Scope of environmental…
 Environmental health is the broadest scope of health problem
definition
 It is a population based science that can be scaled to study
individual within populations
 Problem definition and potential resolution is possible through
the implementation of a systematic approach
Determine the nature and source of hazards
Determine the exposure pathway
The vulnerable/susceptible group
Measure the effects
Apply controls measures at each steps if possible

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 Scope of environmental…
• Waste management: (Solid, Human & liquid waste): Proper
excreta disposal & liquid waste management, Proper
application of storage, collection, disposal: Waste recycling and
generation analysis

• Water supply: Adequacy, safety (chemical, bacteriological,

physical) for domestic, drinking, and recreational use

• Housing and institutional health: Physiological needs,

protection against disease and accidents, psychological needs,
and social comforts in residential and recreational areas

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• Foodhygiene: Food safety and wholesomeness in its
production, storage, preparation, distribution, sale, until
consumption

• Arthropod and Rodent control: Control of disease

transmitting and harmful arthropods and animals

• Atmospheric conditions to ensure that the external

atmosphere is free from harmful elements and that the
internal conditions of workshops, houses, etc. are suitable
for the occupations undertaken in them

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• Occupational health /hygiene: Occupational health
service, sanitation, safety in working settings
• Hygiene education
• Urban and regional planning
• Environmental health aspects of air, sea or land transport
• Public recreation and tourism, in particular the
environmental health aspects of public beaches
swimming-pools, camping, disasters and migrations of
population

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The role of environmental health in public
health

To break the chain of disease transmission

 What’s chain of disease transmission?
 How?

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 Chain of Disease Transmission

• This refers to a logical sequence of

factors or links of a chain
that are essential to the development of the infectious agent
and propagation of disease

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For the development of the infectious process, six factors are
essential:

1. Etiological or a causative agent

2. A reservoir or source of infection of the causative
agent
3. A mode of escape from the reservoir
4. A mode of transmission from the reservoir to the
potential new host
5. A mode of entry into the new host
6. A susceptible host

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Major determining factors in the chain diseases
transmision

Host

Enviro
Agent
nment
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Agent
• Sterilization (the process of killing all microorganisms
including spores)
• Disinfection (the application of chemicals to materials,
which come in to contact with or are ingested by
humans, for the purpose of killing pathogenic
microorganisms)
Host
• Personal hygiene
• Immunization
• Nutrition
• Isolation

Environment
• Environmental manipulation
• Environmental sanitation

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 Role…
Therefore, to stop the spread of a communicable disease,
attacking the agent,
protectingthe host or
changing the environment can break the chain

The environmental health also plays an important

role in the control of other non- communicable
disease, such as chemical poisoning of the air, land and
water, occupational disease, etc.

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