As the human population and technology have grown, our impact on the environment—and subsequently, on our own health—has also grown. The World Health Organization (2014) defines environmental health as “all the physical, chemical, and biological factors external to a person, and all the related factors impacting behaviors. It encompasses the assessment and control of those environmental factors that can potentially affect health. It is targeted towards preventing disease and creating health-supportive environments. This definition excludes behavior not related to environment, as well as behavior related to the social and cultural environment, and genetics.”

To understand environmental health, we must first understand the environment and its many interrelated systems. We do not often think about the Earth beyond what we see around us every day, but the environment spans from the core of the Earth to the outer reaches of the troposphere. The four main divisions of the Earth system are the lithosphere (crust and mantle), hydrosphere (water), atmosphere (gases surrounding earth), and biosphere (area supporting life). Life on Earth depends on the biogeochemical cycles that occur within each of these regions. Biogeochemical cycles recycle energy and chemicals through the lithosphere, hydrosphere, atmosphere, and biosphere. Within the biosphere there are specific divisions called biomes. Biomes are characterized by similar climate, soil, plants, and animals. Because humans dominate most ecosystems on Earth, we have a large impact on the environment. Overpopulation and demands on natural resources can degrade the environment. Since the environment provides us with so many resources such as clean air, clean water, and nutrients, environmental degradation directly influences human health.

Environmental scientists and government officials look for ways to preserve the environment and conserve environmental resources. By monitoring human demand on the environment, laws such as the Endangered Species Act, Clean Air Act, and Clean Water Act have worked to protect the environment for future generations. While technology has created many problems for the environment, it is also being used to benefit the environment and human health. New farming techniques, waste management methods, and pollution control devices all help to keep the environment healthy and protect human health. Environmental health is everyone’s responsibility. Public health officials and governmental leaders are on the front lines, but the decisions made daily by businesses and individuals directly affect our health and the health of the environment.