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Health hazards of the environment

The earth is in peril. Life is under attack from a new enemy: a polluted environment, created by a systemic failure to practice responsible stewardship of our planet. Industrial greed decimates rain forests. Hazardous wastes pollute our waterways and oceans. Global warming changes weather patterns around the world. Overpopulation places an intolerable burden on the earth’s resources.

These and other news relating to our earth’s environment are routinely in the media. But are we aware of less-publicized environmental factors that affect our lives in our homes, in our workplace, in our classrooms? Consider the following.

Indoor environment

Most of us spend a lot of time indoors—eating, working, traveling, sleeping, and shopping. But one might ask, how does this relate to environmental health? Already in 1986, a United States Environmental Protection Agency (EPA) report revealed that air pollution levels inside most buildings are generally five times higher than in the air outside.1 The World Health Organization estimates that 30 percent of all new or renovated buildings suffer from “sick building syndrome” (see sidebar, p. 17).

Some may say, “We live in a less-developed country and therefore we don’t have to worry about the problems associated with modern building structures.” However, in developing countries, high levels of indoor air pollutants contribute to various acute respiratory infections (ARI) in children and adults, and these infections result in an estimated 4.3 million deaths per year.2 Among all endemic diseases, including diarrhea, ARI is the most pervasive cause of chronic illness and is responsible for 34 percent of all mortality for children under the age of five in the developing world.3

In Latin America, Africa, and Asia, 40 to 60 percent of all fuel used for cooking is biomass in origin (wood, cow dung, and other vegetation). Using biomass fuel in a traditional stove captures only 5 to 15 percent of the energy for cooking the food, while the rest is wasted in the form of unused heat and copious quantities of smoke. Studies have shown that homes that use biomass fuels often exceed by 20-fold air-quality exposure limits recommended by the World Health Organization. In fact, the pollution levels in such homes often exceed the worst air pollution of the world’s major metropolitan areas. People primarily impacted by cooking smoke are women and children, who traditionally do more than 90 percent of household chores.

Work environment

According to the World Health Organization, 60 to 70 percent of all adult males and 30 to 60 percent of all adult females are employed outside the home.4 The workplace, even in relatively modern societies, can be potentially hazardous to human health. More than 100 million work-related cases of illness are reported worldwide each year. A U.S. National Institute for Occupational Safety and Health (NIOSH) funded research project showed that in the United States in 1992, direct and indirect costs of occupational injuries and illnesses totaled $145 billion and $26 billion respectively. These costs compare to $33 billion for HIV/AIDS, $67.3 billion for Alzheimer’s disease, $164.3 billion for circulatory disease, and $170.7 billion for cancer.5

Other illnesses

Asthma, a condition that affects millions, is a disorder of the airways that lead into the lungs. In an acute asthmatic attack, these airways constrict and consequently obstruct the flow of air. This condition obviously leads to considerable discomfort and occasionally results in death. Although worldwide data is difficult to secure, reports from various health agencies suggest that asthma and its management have developed into a major public health problem in many countries. Data for the United States suggests that asthma prevalence rates among children and youth under the age of 20 doubled between 1982 and 1991 (from 3 to 5 percent), while asthma related mortality rates for persons aged 5 to 34 increased by roughly the same amount.6

Although an asthma attack may be precipitated by exercise, stress, change in weather, allergies, and other contributors, a key factor in the development of asthma and subsequent asthmatic episodes is exposure to indoor environmental triggers such as tobacco smoke, cleaning compounds, mites, animal dander, and cockroaches.

Environmental hazards also contribute to the re-emergence of many vector-borne and infectious diseases. Health professionals believed that many of these common diseases would be eradicated by the turn of the century. Unfortunately, they are making a comeback due to drug resistance and environmental factors. A case in point is malaria. Thirty years ago, public health professionals believed that this, a potentially fatal disease, which is transmitted by mosquitoes, would soon be a thing of the past. However, due to environmental factors and the mosquito’s growing tolerance for pesticides and malaria’s drug resistance, 55 percent of the world population is now routinely exposed to malaria. This disease kills up to 2 percent of Africa’s children each year. Annually, 300 to 500 million new cases are reported worldwide, with an estimated mortality of 1.5 to 3 million people.7

Another example of an environmentally related infectious disease that continues to resist control is tuberculosis (TB). TB is caused by a bacteria that is transmitted from person to person through airborne droplets produced by coughing or sneezing. Untreated, tuberculosis can be debilitating and potentially fatal. Approximately one-third of the world’s population has TB and about two-thirds of the population in developing countries are carriers of the organism.8 Tuberculosis infection rates are often highest in environments where people are densely crowded, ventilation is marginal, and sunlight is weak or absent.

Other diseases that arise from poor environmental conditions include hepatitis, cryptosporidiosis, dengue hemorrhagic fever, diarrheal diseases, encephalitis, and numerous other illnesses. Human migration and expanded air travel increase environmental interconnectedness, and in a very short while environmental diseases from one part of the world can impact other faraway places. Distance no longer provides immunity.

Yes, our planet is sick. And environmental hazards can make us fall a prey to one or more of the illnesses caused by a polluted environment. Governments, health organizations, and industries can do a lot. But the question is: What should we as individuals do? Here’s a simple list within our reach.

What can we do?

1. Be a good steward. That’s the first principle of ecology we learn from the Bible. The Genesis record tells us that after God created the earth in all its beauty and perfection, He gave it to human beings “to dress it and to keep it” (Genesis 2:15, KJV). God gave us the earth for our good and for our enjoyment—for food, for beauty, for work—and we are to care for it as good stewards. Good stewardship means that we do not carelessly exploit the earth’s resources and cause environmental imbalances that create hazards to life and health.

2. Follow sound principles of hygiene. The Bible provides us good examples of basic sanitary practices. Leviticus (15:2-12) instructs individuals who have come in contact with contagious or contaminating diseases to cleanse themselves before interacting with other people. Deuteronomy 23:14 speaks about personal and environmental cleanliness because the Lord is always with us. Says Ellen White: “Perfect cleanliness, plenty of sunlight, careful attention to sanitation in every detail of the home life, are essential to freedom from disease and to the cheerfulness and vigor of the inmates of the home.”9 Personal hygiene is a Christian duty.

3. Use simple preventive methods. The risk associated with most environmental problems can be minimized by some basic prevention. Public health officials advise that routine hand-washing with soap and water will minimize transmission of many communicable diseases. This is particularly important for parents, child-care professionals, medical practitioners, and food handlers.

Keeping the home clean both inside and out can provide a healthful environment. Periodically remove dust from counter-tops, bedposts, and other surfaces by dusting with a damp rag. This will minimize dust and other particles that can exacerbate allergies or initiate an asthma episode.

Wash your bed linen regularly. Infestation by mites, which feed on dead skin, can heighten the risk of developing asthma and allergies. By routinely washing your bed linen and pillow covers and exposing the mattresses and pillows to the sun, you will minimize this risk.

If you use an indoor vacuum cleaner, or are cleaning or renovating a room, be certain to open the windows and doors. Excess dust or chemicals that can aggravate pre-existing medical conditions can be safely diluted by lots of fresh outdoor air.

Vent wood-burning stoves and fireplaces outside. Gases generated from the combustion of biomass fuel can create both short- and long-term respiratory problems. A reliable chimney will minimize the concentration of smoke.

If your home has a mechanical (forced air) ventilation system, inspect and change the filters on a regular basis. This will prevent potentially pathogenic microbes from establishing themselves in the ventilation system of your home, where they can be easily distributed to every living space.

Screen your windows and doors to minimize entry of disease-carrying insects.

4. Maintain clean your home surroundings. Keep your yard free of depressions, debris, and trash that can act as collection points for water. Puddles and rainwater that accumulates in tires, automobile parts, and even un-maintained bird baths can act as breeding grounds for disease-carrying mosquitos and other vectors.

If you possess a garden pond, stock it with mosquito-eating fish to keep nuisance insects under control.

5. Develop good cooking and eating habits. Cook food thoroughly, particularly if you eat animal products. Foods contaminated with viruses and bacteria can not be made wholesome simply by heating. Cooked meats should ideally be free of any sign of blood. Maintain appropriate temperatures for cold and frozen foods.

6. Keep your workplace environmentally safe. Survey your place of employment to see what occupational hazards that may be present. Educate yourself to recognize potential risk factors and signs of exposure. Many hazardous substances used in manufacturing can be replaced by less-expensive, less-toxic, and equally effective compounds. Both you and your employer will be pleased if you can enhance the safety of the workplace and save money at the same time.

Educate yourself

In addition to the simple measures listed above, you can promote a cleaner environment by keeping yourself informed. Ecology is an ever-expanding science. Being aware of your immediate surroundings and keeping them healthful is part of good stewardship. But you need to know and do more. Internet Web sites provide current, reliable, and useful information about environmental and occupational health. Look up the following sites:

Environmental Health Web Sites:

  • (U.S. Environmental Protection Agency)
  • (U.S. National Institute for Environmental Health Sciences)
  • (World Health Organization)

Workplace Health and Safety Web Sites :

  • (American Industrial Hygiene Association)
  • (U.S. National Institute for Occupational Safety & Health)


The Sick-Building Syndrome

Since the petroleum crisis of the 1970s, architectural design has largely been influenced by the necessity to conserve energy. You can readily identify energy efficient buildings through their design features. Many modern commercial facilities’ windows do not open or close because this would allow expensive tempered air to escape. These buildings usually have tinted windows to reduce glare and minimize overheating caused by the sun’s rays.

Energy efficient buildings may contribute to sick-building syndrome. The symptoms generally do not fit the pattern of any particular illness and their cause is difficult to trace to specific sources. People who suffer from this malady may complain of one or more of the following symptoms: dry or burning eyes, nose, or throat; sneezing, stuffy or runny nose; fatigue or lethargy, headache, dizziness, nausea, irritability, and forgetfulness. Poor lighting, noise, vibration, thermal discomfort, and psychological stress may cause or contribute to these symptoms.

These health problems do not appear in any particular sequence. In some cases, workers experience problems as they enter their offices and diminish as they leave. In other cases, symptoms do not begin until later in the workday. In still other cases, there is no pattern at all. Sometimes there is an outbreak of illness among many workers in a single building; other times, symptoms show up in only a few individuals.

Scientist suggest three major reasons for “sick” buildings:

  1. The presence of numerous indoor air pollution sources. Typically, none of these in itself causes building occupants to feel ill. In most cases, several factors accumulate to a point that some individuals will feel sick when spending time in a building. Some of the routine indoor sources include: tobacco smoke; formaldehyde from pressed wood products and upholstery; fumes from paints, adhesives, and copy machines; and mold and bacteria that come from water-damaged carpets, wood, and other building materials.
  2. Poorly designed and maintained ventilation systems. Perhaps the most important contributor to sick-building syndrome is poor or inadequate ventilation systems. When designed properly, these systems should provide ample quantities of fresh outdoor air to each office.
  3. The use of a building for purposes for which it was not designed. Building occupancy often changes through time. What was once a classroom is now a wet laboratory, and later may become a suite of individual offices. Each use may be valid, but cumulative effects on the environment must be factored, taking into account occupant density as well as prior and present activities.


David Dyjack (Dr.P.H., University of Michigan) is Associate Professor and Chairman of the Department of Environmental and Occupational Health, School of Public Health, Loma Linda University. His address: 1202 Nichol Hall; Loma Linda, California 92350; U.S.A. E-mail: Angela Bennett Dyjack (M.P.H, Loma Linda University) is an Assistant Professor in the Department of Environmental and Occupational Health, School of Public Health, Loma Linda University. Her address: 1203 Nichol Hall; Loma Linda, California 92350; U.S.A. E-mail:

Notes and references

1.   “The Total Assessment Methodology Study.” United States Environmental Protection Agency, Document No. EPA/600/S6-87/002, 1987.

2.   Daniel Kammen, “Energy as an Instrument for Socio-Economic Development,” United Nations Development Project, 1995, pp. 50-60.

3.   K. S. Lankinen, S. Bergstrom, P. H. Makela, and M. Peltomaa, Health and Disease in Developing Countries (New York: The Macmillan Press Limited, 1984), pp. 281-286.

4.   “Global Strategy on Occupational Health for All,” World Health Organization, 1995, pp. 1-4.

5.   U.S. National Institute for Occupational Safety and Health, National Occupational Research Agenda: Update, July 1998, p. 4.

6.   Robert Wallace, ed., Public Health and Preventive Medicine (Stamford, Connecticut: Appleton and Lange, publisher, 1998) 14th edition, pp. 984, 985.

7.   Ibid., pp. 313-316.

8.   M.C. Raviglione, D.E. Snider, and A. Kochi, “Global Epidemiology of Tuberculosis: Morbidity and Mortality of a Worldwide Epidemic,” Journal of the American Medical Association, 273 (1995): 220-226.

9.   Ellen G. White, The Ministry of Healing (Mountain View, Calif.: Pacific Press Publ. Assn., 1909), p. 276.