Although we are intricately linked to the environment, for simplicity we refer to it as all that is external to us. More specifically, we experience it as a combination of physical, chemical and biological conditions, which may be modified in turn by social, cultural and economic circumstances. As such, a healthy environment is essential for human health and well-being.

Environmental health threats have always accompanied human populations. Despite technological and economic advances, today many parts of the world still experience environmental hazards which are associated with poverty and lack of development. They include lack of access to safe drinking water, inadequate basic sanitation, contamination of food with pathogens, indoor air pollution from the use of biomass fuel, and inadequate waste disposal, among others. In addition we are also confronted with a wide set of hazards related to rapid and unsustainable development that lacks safeguards for health and environment. These hazards include water pollution from industry, agriculture and urban centres, ambient air pollution from transport, industry and coal power stations, accumulation of solid and hazardous wastes, and chemical and radiation hazards.

		Natural systems must be preserved to protect human health.

Although until recently in human history we have had the skills to modify only our local environment, we are now contributing to global environmental changes which may further threaten our health and well-being or that of future generations. The major drivers of global environmental change include policies that determine trends in economic development, technology and science, consumption patterns and population growth. Our personal actions also count. The sum of all our small individual efforts to maintain a healthy environment can become indeed a contribution of global proportions.

Dr. Carlos Corvalán, Scientist
Department of Protecions of Human Environment
World Health Organisation. CH-1211,
Geneva 27
Tel.: +41-22-791 4204
Fax: +41-22-791 4123
E-mail: corvalanc@who.it