California Department of Public Health logo: three likenesses of people colored blue, green, and orange  
Last Edited: 1/29/2008

What is environmental health?

Different agencies define "environmental health" in different ways. For local county health departments, environmental health may refer to food safety, septic systems, building permits, and public nuisances. Federal agencies may also be concerned about earthquakes, flooding, and quality of life issues like noise. EHIB works to protect the health of Californians by monitoring environmental contaminants and their related diseases, studying the impact of these contaminants on human health, and by informing the public about how to best protect their health from harmful pollutants.

How can the environment affect my health?Sources of Pollution (traffic, pesticides, water contamination)

For better or worse, chemicals and other contaminants have become a part of every day life. They exist in every aspect of our lives even before we are born. Some contaminants, like mold, are found naturally in the environment; other contaminants (like chemicals) are created by humans. Hundreds of new chemicals are created every year.

Exposure to large amounts of any substance can be harmful to one’s health. However, some contaminants are more harmful, or toxic, than others.

There are many types of toxicity. When thinking about toxicity, researchers consider a chemical’s ability to cause or promote cancer, or cause neurological problems (damage to the brain and nervous system), respiratory problems (like asthma), and reproductive problems (chemicals that may harm the developing fetus, or an individuals ability to conceive).

It is important to remember that some chemicals in small amounts can improve or protect one’s health. Chlorine, which is used to purify drinking water, can be toxic in large quantities. In small quantities it protects us from cholera and other diseases.

There are many steps that must be taken in order to determine if a chemical in the environment is a health risk for people.

First researchers must identify a source of contamination. The source may be specific, like a hazardous waste site, or more general, like air pollution.

Second the type of chemical must be determined. There are tens of thousands of chemicals, and researchers are still learning about the toxic effects of many of them. EHIB has listed the most common chemicals here.

Third, one must determine if there is a "pathway" for the chemical to come in contact with a child or adult. Examples of pathways are pesticides that drift from fields into residential areas, contaminated drinking water, and exposure to contaminated dirt at a hazardous site.

Diagram of Exposure Pathways

Finally we must know the amount, or "dose" the person was exposed to.

When we know these four things, we can estimate the potential health risk.

It is important to remember that researchers can only estimate a health risk. Whether an exposure will make you sick or not depends on many factors, including your personal health, diet, genetic make-up, and other chemicals you may have been exposed to in your life.