Environmental health is a branch of public health concerned with
all aspects of the natural and built environment that may affect human health.
Other phrases that concern or refer to the discipline of environmental health
include environmental public health and environmental health and protection.
Environmental health is defined by the World Health Organization as:
Those aspects of the human health and disease that are determined by factors
in the environment. It also refers to the theory and practice of assessing and
controlling factors in the environment that can potentially affect health.
Environmental health as used by the WHO Regional Office for Europe, includes
both the direct pathological effects of chemicals, radiation and some
biological agents, and the effects (often indirect) on health and well being
of the broad physical, psychological, social and cultural environment, which
includes housing, urban development, land use and transport.
Environmental health services are defined by the World Health Organization as:
those services which implement environmental health policies through
monitoring and control activities. They also carry out that role by promoting
the improvement of environmental parameters and by encouraging the use of
environmentally friendly and healthy technologies and behaviors. They also
have a leading role in developing and suggesting new policy areas.
Environmental health practitioners may be known as sanitarians, public health
inspectors, environmental health specialists, environmental health officers or
environmental health practitioners. In many European countries physicians and
veterinarians are involved in environmental health. Many states in the United
States require that individuals have professional licenses in order to practice
environmental health. California state law defines the scope of practice of
environmental health as follows:
"Scope of practice in environmental health" means the practice of
environmental health by registered environmental health specialists in the
public and private sector within the meaning of this article and includes, but
is not limited to, organization, management, education, enforcement,
consultation, and emergency response for the purpose of prevention of
environmental health hazards and the promotion and protection of the public
health and the environment in the following areas: food protection; housing;
institutional environmental health; land use; community noise control;
recreational swimming areas and waters; electromagnetic radiation control;
solid, liquid, and hazardous materials management; underground storage tank
control; onsite septic systems; vector control; drinking water quality; water
sanitation; emergency preparedness; and milk and dairy sanitation pursuant to
Section 33113 of the Food and Agricultural Code.
The environmental health profession had its modern-day roots in the sanitary and
public health movement of the United Kingdom. This was epitomized by Sir Edwin
Chadwick, who was instrumental in the repeal of the poor laws and was the
founding president of the Association of Public Sanitary Inspectors in 1884,
which today is the Chartered Institute of Environmental Health.
Environmental medicine may be seen as the medical branch of the broader field of
environmental health. Terminology is not fully established, and in many European
countries they are used interchangeably.
Disciplines
Three basic disciplines generally contribute to the field of environmental
health: environmental epidemiology, toxicology, and exposure science. Each of
these disciplines contributes different information to describe problems in
environmental health, but there is some overlap among them.
Environmental epidemiology studies the relationship between environmental
exposures (including exposure to chemicals, radiation, microbiological
agents, etc.) and human health. Observational studies, which simply observe
exposures that people have already experienced, are common in environmental
epidemiology because humans cannot ethically be exposed to agents that are
known or suspected to cause disease. While the inability to use experimental
study designs is a limitation of environmental epidemiology, this discipline
directly observes effects on human health rather than estimating effects
from animal studies.
Toxicology studies how environmental exposures lead to specific health
outcomes, generally in animals, as a means to understand possible health
outcomes in humans. Toxicology has the advantage of being able to conduct
randomized controlled trials and other experimental studies because they can
use animal subjects. However there are many differences in animal and human
biology, and there can be a lot of uncertainty when interpreting the results
of animal studies for their implications for human health.
Exposure science studies human exposure to environmental contaminants by
both identifying and quantifying exposures. Exposure science can be used to
support environmental epidemiology by better describing environmental
exposures that may lead to a particular health outcome, identify common
exposures whose health outcomes may be better understood through a
toxicology study, or can be used in a risk assessment to determine whether
current levels of exposure might exceed recommended levels. Exposure science
has the advantage of being able to very accurately quantify exposures to
specific chemicals, but it does not generate any information about health
outcomes like environmental epidemiology or toxicology.
Information from these three disciplines can be combined to conduct a risk
assessment for specific chemicals or mixtures of chemicals to determine whether
an exposure poses significant risk to human health. This can in turn be used to
develop and implement environmental health policy that, for example, regulates
chemical emissions, or imposes standards for proper sanitation.
