Reduced Risk

The incidence of poor health has increased in the U.S., due in part to an increase in environmental threats and risks. Yet natural elements can be planned and managed to improve the environmental performance of built environments as well as mitigate the health risks and impacts of urban living. Provision of parks and nature can be part of the public health solution.

Fast Facts

  • Based on multiple studies1 the U.S. Forest Service estimates that urban trees perform a range of environmental services that make cities healthier places, including improved air and water quality, energy savings, noise abatement, and improved soils. In total these services provide billions of dollars of value each year.
  • Estimated total annual air pollution removal (of ozone, particulate matter, NO2, SO2, and carbon monoxide) across 55 U.S. cities is 711,000 metric tons, representing $3.8 billion in public value.2
  • Urban heat island effect occurs in built up areas. Parks can be up to 2°F cooler than the surrounding urban area in the day.3 Large numbers of trees and expansive green spaces across a city can reduce local air temperatures by up to 9°F.4
  • An increase of 343 trees/km2 was associated with a 29% lower early childhood prevalence of asthma in New York City.5
  • Appealing and easily accessible green environments may motivate and encourage physical exercise. Activity in outdoor green spaces - at any level, intensity, duration, or type – has been associated with mental and physical benefits.6,7,8
  • Poorer people generally have poorer health. One study found that people who are exposed to green space have lower levels of illness and disease than other people of similar income. Physical environments that promote good health may reduce socioeconomic health inequalities.9
  • Community gardening may help improve one’s diet. Adults were 3.5 times more likely to consume at least five servings of fruit or vegetables a day if someone in their household had participated in a community gardening project within the last 12 months.10

More information later . . . .


1. Nowak, DJ, SM Stein, PB Randler, EJ Greenfield, SJ Comas, MA Carr, and RJ Alig. 2010. Sustaining America's Urban Trees and Forests: A Forests on the Edge Report. U.S.D.A. Forest Service, General Technical Report NRS-62. Newtown Square, PA: Northern Research Station, 27 pp.

2. Nowak, DJ, DE Crane, and JC Stevens. 2006. Air Pollution Removal by Urban Trees and Shrubs in the United States. Urban Forestry & Urban Greening 4, 3-4:115-123.

3. Bowler, DE, L Buyung-Ali, TM Knight, and AS Pullin. 2010. Urban Greening to Cool Towns and Cities: A Systematic Review of the Empirical Evidence. Landscape and Urban Planning 97:147-155.

4. McPherson, EG. 1994. Cooling Urban Heat Islands with Sustainable Landscapes. In: Platt, RH, RA Rowntree, and PC Muick (eds), The Ecological City: Preserving and Restoring Urban Biodiversity. University of Massachusetts Press, pp. 161-171.

5. Lovasi, GS, JW Quinn, KM Neckerman, MS Perzanowski, and A Rundle. 2008. Children Living in Areas with More Street Trees Have Lower Prevalence of Asthma. Journal of Epidemiology and Community Health 62:647-49.

6. Thompson, CW. 2011. Linking Landscape and Health: The Recurring Theme. Landscape and Urban Planning 99:187-195.

7. Stigsdotter, UK, O Ekholm, J Schipperijn, M Toftager, F Kamper-Jørgensen, and TB Randrup. 2010. Health Promoting Outdoor Environments - Associations Between Green Space and Health, Health-Related Quality of Life, and Stress Based on a Danish National Representative Survey. Scandinavian Journal of Public Health 38, 4:411-17.

8. Pretty, J, R Hine, and J Peacock. 2006. Green Exercise: The Benefits of Activities in Green Places. Biologist 53, 3:143-48.

9. Mitchell, R, and F Popham. 2008. Effect of Exposure to Natural Environment on Health Inequalities: An Observational Population Study. The Lancet 372, 9650:1655-660.

10. Alaimo, K, E Packnett, RA Miles, and DJ Kruger. 2008. Fruit and Vegetable Intake Among Urban Community Gardeners. Journal of Nutrition Education and Behavior 40, 2:94-101.


credit: Margaret Bourke-White, Lunch Atop a Skyscraper, c. 1932

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