What is environmental health?

This section gives information about what environmental health is, and why the environment is important to human health.

What is environmental health?

The environment can directly and indirectly impact on our health and wellbeing. Environmental health examines the interaction between the environment and our health. 

We use the following definitions:

  • Environmental health refers to aspects of human health (including quality of life) that are determined by physical, chemical, biological, social and psychosocial factors in the environment.
  • Environment broadly includes everything external to ourselves, including the physical, natural, social and behavioral environments. 
  • Health is a state of complete physical, mental and social wellbeing, and is not merely the absence of disease or illness.   

Why is the environment important for health?

We need safe, healthy and supportive environments for good health. The environment in which we live is a major determinant of our health and wellbeing.  We depend on the environment for energy and the materials needed to sustain life, such as:

  • clean air
  • safe drinking water
  • nutritious food
  • safe places to live.

Many aspects of our environment – both built and natural environment – can impact on our health. It’s important that we interpret health issues in the wider context of our environment and where we live

Figure 1: Determinants of health and well-being in our neighbourhoods

Fig 1: Determinants of health and well-being in our neighbourhoods

Source: Barton and Grant 2006 [1]

Many aspects of the environment can affect our health. Environmental hazards can increase the risk of disease, including cancer, heart disease and asthma [2].

Table 1 gives examples of how different aspects of the environment can affect our health.

Table 1: Environmental exposures and related human health effects

Environmental exposure Examples of health effects
Outdoor air pollution Respiratory conditions, cardiovascular disease, lung cancer
Unsafe drinking water Diarrhoeal (gastrointestinal) illnesses
Contaminated recreational water Diarrhoeal (gastrointestinal) illnesses; eye, ear, nose and throat infections
Mosquitoes, ticks and other vectors Malaria, dengue fever, Rickettsial disease
UV (ultraviolet light) exposure

Too much: melanoma, non-melanoma skin cancer, eye cataracts

Too little: vitamin D deficiency, leading to rickets, osteoporosis and osteomalacia

Second-hand smoke exposure

In infants: low birthweight, sudden unexpected death in infancy (SUDI)

In children: asthma, lower respiratory infections, middle ear infections

In adults: ischaemic heart disease, stroke, lung cancer 

Household crowding Infectious diseases, including lower respiratory infections
Cold and damp housing Excess mortality
Climate change Infectious diseases, including giardiasis, cryptosporidiosis and salmonellosis; heat stroke
Hazardous substances Poisoning, burns, dermatitis

In children: developmental delays, behavioural problems

In adults: increased blood pressure

Asbestos Breathing difficulties, lung cancer, mesothelioma
Noise Hearing loss, cardiovascular problems, insomnia, psychophysiological problems

Environmental burden of disease worldwide

Globally, environmental factors contributed to an estimated 23 percent of all deaths in 2002.

Children under 15 years were particularly affected, with 36 percent of all deaths accounted for by environmental factors [3].

Even in developed countries, environmental factors play a large role in the burden of disease.

In 2002, 17 percent of all deaths were attributable to environmental factors in developed countries in the Western Pacific (New Zealand, Australia, Japan, Singapore and Brunei Darussalam).

For more information on our New Zealand Environmental Burden of Disease Study, go to the environmental burden of disease webpage.


1. Barton H, Grant M. 2006. A health map for the local human habitat. The Journal for the Royal Society for the Promotion of Health 126(6): 252–261. doi: 10.1177/1466424006070466

2. Resnik DB, Portier CJ. 2008. Environment and Health. In M Crowley (Ed.), From Birth to Death and Bench to Clinic: The Hastings Center Bioethics Briefing Book for Journalists, Policymakers, and Campaigns (pp. 59–62). Garrison, NY: The Hastings Center.

3. Prüss-Üstün A, Corvalán C. 2006. Preventing Disease Through Healthy Environments. Towards an estimate of the environmental burden of disease. Geneva: World Health Organization.

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