1. Introduction to Environmental Health
(OPLAS)
OPEN PROGRAM OF LEARNING
AND
ASSISTING STUDENTS.
Introduction to Environmental Health
Supporting text used:
Moeller, Dade W. “Environmental Health.” Harvard University Press, Cambridge Massachusetts. 1992
Yassi, A., Kjellstrom, T., de Kok, T., and Guidotti, T. “Basic Environmental Health.” Oxford University Press for the World Health Organization

2. 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 where the living and working environment is protected from life-threatening and health threatening pollutants, pathogens and physical hazards’(Who, 1992a)
To start, we must have an understanding of what variable or aspect of an individual is compromised. One’s health is what is vulnerable to lack of exposures to nutrients and to exposures to hazardous agents. Change in a health state is measured or characterized by a change in the degree of functionality. If someone is in poor health they cannot function to their average potential.

3. Definition: ‘Environment’
‘…[All] that which is external to individual human host. [It] can be divided into physical, biological, social cultural any or all of which can influence health status in populations.’ (WHO, 1995)
The first definition alludes to the interdependence of health and accessibility of resources in the surrounding environment. This definition defines what an environment is.

4. 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 adversely the health of present and future generations’ (WHO, 1993a)
The term ‘environmental health’ is used to describe problems that arise in the relationship of the environment and health of populations within the environment.

5. Definition: ‘Health Effect…’
‘…is the specific damage to health that an environmental hazard can cause an individual person. Often the same hazard can cause a range of different effects of different severity.’ (Yassi et al., 2001)
This definition emphasizes the adverse effects that the environmnet may have on health. In truth, the environment also has beneficial effects which are not implied in this definition. The environment may also provide nutrients and medicines to remediate dysfunctionality.

6. Interdependence Health depends on resources.
Good health depends on accessibility to sustainable resources.
Bad health results from inaccessibility to sustainable resources or exposure to a hazard.
Sustainable resources and hazards exist in the environment.
Therefore, quality of health depends on the environment

7. Interdependent Environments
A relational definition of environment is a function of scale, boundaries, spatial proximity and recipient populations
When considering a global scale, focus is on the effect of an unbounded environment, e.g. air, on all populations anywhere

8. Interdependent Environments
When considering local scale, focus is on effect of both a bounded and an unbounded environment, e.g. water and air, on a subpopulation closest to the exposure event
The local scale is a subpart of the global scale

9. Population Perspective of Relations
All populations
Human population
Community, nation
Family
Problem definition involves many different perspectives. The first perspective shown here, is to define and approach environmental health problems by focusing on the indicator of change. Here, either and individual or a population may show a change in their health. The change may be positive (beneficial by a gain in health quality, e.g. increased longevity) or it may be negative (adverse by a loss in health quality, e.g. decreased functionality).
Individual

10. Health and Environment Perspective of Relations
Environmental health
Public Health
Occupational Health
Family Health
In contrast, another perspective may focus on the scale of the environment in which the individual or populations lives. Sudden changes in personal health results more from incidental exposure. These sudden changes in personal health are highly dependent on the frame of reference at a time of exposure. As the population size and scope increases, time becomes less important but still necessary and location becomes more important in identifying changes in health.
Personal
Health

11. In contrast, another perspective may focus on the scale of the environment in which the individual or populations lives. Sudden changes in personal health results more from incidental exposure.
These sudden changes in personal health are highly dependent on the frame of reference at a time of exposure.
As the population size and scope increases, time becomes less important but still necessary and location becomes more important in identifying changes in health.

12. The end