Broadly defined, the environment includes all that is external to an individual -- the air we breathe, the water we drink and use, the land and built structures that surround us -- all of the natural as well as human-formed conditions that influence the quality of our lives. Our interactions with the environment are complex and not always healthy.
A healthy community environment encompasses aspects of human health, disease, and injury that are determined or influenced by factors in the overall environment. Examining the interaction between health and the environment requires studying not only how health is affected by the direct pathological impacts of various chemical, physical, and biologic agents, but also by factors in the broad physical and social environments, which include housing, urban development, land use, transportation, industry, and agriculture.
Since 1900, life expectancy in the United States has increased by approximately 40 years. Only seven of those years can be attributed to improvements in disease care while the rest are the result of improved prevention efforts (such as immunizations) and improved environmental conditions, including sanitation and water. The link between the nation’s health and the environment is unmistakable. (cdc.gov)