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The urban environment

deaths from urban air pollution map

Over the next thirty years, most of the world’s population growth will occur in cities and towns of poor countries1. Even while population growth rates in Asia, for instance, are falling dramatically, the region will see an absolute increase of nearly a billion people over the next three decades –growth concentrated mostly in urban areas2. In Africa, the urbanization process also is occurring apace. For example, in the United Republic of Tanzania, the population of Dar es Salaam is doubling every 12 years3.

Rapid, unplanned and unsustainable patterns of urban development are making developing cities focal points for many emerging environment and health hazards4. As urban populations grow, the quality of the urban environment, will play an increasingly important role in public health with respect to issues ranging from solid waste disposal, provision of safe water and sanitation, and injury prevention, to the interface between urban poverty, environment and health.

Unsustainable patterns of transport and urban land use are a driver, or root cause, of a number of significant, and interrelated environment and health hazards faced by urban dwellers in developing countries. These health and environment linkages cut across a range of policy sectors and thus are often overlooked in policymaking. They are a focus of this Priority Risks section on the urban environment.

See enlarged map [pdf 257kb]


  • Urban air pollution – of which a significant proportion is generated by vehicles, as well as industry and energy production – is estimated to kill some 800,000 people annually5. Today, many developing world cities face very severe levels of urban air pollution – higher than developed world counterparts6 7.
  • Road traffic accidents contribute a further 1.2 million deaths annually; low- and middle-income countries bear 90 % of the death and injury toll. Degradation of the built urban and rural environment – particularly for pedestrians and cyclists – has been cited as a key risk factor8 9.
  • Current patterns of urbanization and motorization also are associated with more sedentary lifestyles, diminished space and opportunities for physical activity, and a consequent surge in related non-communicable diseases. 10 11 12Physical inactivity is estimated to be responsible for some 1.9 million deaths globally every year, as a result of disease such as heart ailments, cancer and diabetes13.

Cost-effective strategies to address such linkages do exist. More integrated transport and land use – including the development of high capacity, dedicated busways and pedestrian/cycle networks – have become central to policy in Latin American cities such as Bogotá and Curitiba, and similar models are being examined/tested in other cities of Africa, the Americas and Asia. Reducing transport pollution emissions, and their health impacts, through the use of cleaner fuels and vehicle technologies has been an issue addressed in the African context, and elsewhere. These experiences are detailed in the links below.


Work to address environment and health issues in developing cities, and urban transport in particular, is carried out in the framework of the United Nations Environment Programme (UNEP); the United Nations Human Settlements Programme (UN-HABITAT); the World Health Organization (Healthy Cities Network); and within other United Nations, international and development agencies, as well as at the country level. For resources on environment and health in urban areas in general, and with respect to transport in particular, see the following.

Brief general directory of urban programmes/web portals

Policy briefing on transport, environment and health in developing cities

Urban environment illustration
UNEP/Permdahl Vesm; UNEP; UNEP/Carmel Fatima

Directory of web accessible resources

Topic index

Overview of environment and health linkages
Case-studies: health and environment impacts
Case studies of good practice management/strategies
Economic impacts and economic evaluation
Training and capacity building
Advocacy and community participation
Surveillance and monitoring of health and environment indicators and trends
Related health and environment conventions, legal agreements, and strategic policies
United Nations Environment Programme, World Health Organization, and other United Nations agency links
Other organizational links
Selection criteria and disclaimer


  • World urbanization prospects: The 2003 revision. United Nations Department of Economic and Social Affairs, Population Division: New York. (Accessed August, 2004:
  • Health effects of outdoor air pollution in developing countries of asia; a literature review. Health Effects Institute, April 2004. (Accessed July, 2004 : http: de Jong, R. The environmental impact of cities. In Habitat Debate. United Nations Human Settlements Programme - UN-Habitat . June 2002, 8(2)5.
  • Montgomery, M., et al., eds. N.R.C. Panel on Urban Population Dynamics.Cities Transformed: Demographic Change and its Implications in the Developing World.. London, Earthscan, 2004:529.
  • The world health report 2002 – reducing risks, promoting healthy life. Geneva, World Health Organization, 2002.
  • Kenworthy J, Laube F. Urban transport patterns in a global sample of cities and their linkages to transport infrastructures, land use, economics and environment. World Transport Policy and Practice, 2002, 8(3):5–20.
  • Health effects of outdoor air pollution in developing countries of Asia: a literature review. Boston, Health Effects Institute, 2004.
  • Peden M et al., eds. World report on road traffic injury prevention. Geneva, World Health Organization, 2004.
  • Nantulya VM, Reich MR. The neglected epidemic: road traffic injuries in developing countries. British Medical Journal, 2002, 324(7346):1139–1141.
  • Neglected global epidemics: three growing threats. The world health report 2003 – shaping the future. Geneva, World Health Organization, 2003.
  • Physical activity, environmental issues. Geneva, World Health Organization (accessed 4 October, 2004).
  • Dora C, Phillips M, eds. Transport, environment and health. Copenhagen, World Health Organization Regional Office for Europe, 2000 (WHO Regional Publications, European Series, No. 89).
  • The world health report 2002 - reducing risks, promoting healthy life. Geneva, World Health Organization, 2002.


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Ecosystems and human well-being: Health synthesis

Millennium Ecosystem Assessment

Health/environment journals on line





Health & environment: tools for effective decision-making

Health & environment: tools for effective decision-making

The WHO-UNEP Health and Environment Linkages Initiative (HELI): Review of initial findings

Information package in environmental and occupational health

Information package in environmental and occupational health

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