Trees Found to Improve Air Quality & Human Health

Nov 30, 2011


Contacts: Gary Allen (301) 717‐1579
Eric Sprague (443) 837‐5248
Trees Improve Air Quality and Protect Human Health

Annapolis, MD, November 18, 2011 – New data shows that trees can significantly improve air quality in metropolitan areas like Baltimore, MD and Washington, DC by filtering out pollution that is damaging to human health.


Released by the Center for Chesapeake Communities and Pinchot Institute for Conservation, the data shows that the trees in the Washington, DC area remove over 8.3 million pounds of nitrogen dioxide each year.  To achieve a similar pollutant reduction, over 274,000 cars would need to be taken of the road each year.  Based on studies of the costs of pollution to society such as health care, the District’s tree cover saves nearly $51 million annually1.   In the Baltimore, MD area, trees remove close to 5 million pounds of nitrogen dioxide annually —equal to removing 183,000 cars from the road and saving over $26 million in associated health care costs each year.


By lowering city temperatures and removing pollutants from the air, trees can reduce the risk to residents of developing a number of health problems including heart and lung disease and asthma, and ultimately reduce premature deaths.  These benefits are important to Baltimore and Washington, DC residents as these communities are currently not meeting federal air quality standards for ozone and particulate matter.


Trees can provide benefits to local neighborhoods as well:


  • Tanglewood Park in northern Prince George’s County, Maryland removes over 3,500 pounds of ozone‐forming pollutants per year.  This service saves residents $16,000 every year in avoided costs.


  •   The trees of Rock Creek Park in Washington, DC remove 63,500 pounds of ozone‐forming pollutants each year, which has a value of $285,000 dollars each year.


  •  Fountainhead Regional Park along the Occoquan Reservoir in Virginia removes nearly 89,000 pounds of ozone each year, which has a value of almost $400,000 each year.


Center for Chesapeake Communities Executive Director Gary G. Allen noted, “Protecting trees and woods in urban areas just makes sense. It not only saves money for the city in reduced health care costs, it is one of the most cost‐effective and multi‐benefit strategies for meeting regional air quality goals.”

1 US Forest Service, Northern Research Station, Syracuse, NY. Unpublished results of i‐Tree analysis of 2007 county data. October 2011



These findings could influence how the US Environmental Protection Agency considers trees in meeting air quality standards in the Baltimore and the Washington, DC metropolitan areas. Communities across the country are increasingly including tree cover in air quality plans to help them meet federal standards, however, the US EPA guidelines currently consider tree cover only a voluntary measure. The Center for Chesapeake Communities, Virginia Department of Forestry, and Pinchot Institute for Conservation, with funding from the USDA Forest Service, are investigating ways that these benefits can be used to allow landowners and local jurisdictions to take air quality “credit” for their tree planting and protection efforts.


“It is our hope that this effort will lead to landowners being able to market their forest’s air quality benefit,” said Virginia State Forester Carl Garrison.


Tad Aburn, Director of the Air and Radiation Management Administration at the Maryland Department of the Environment stated, “Maryland looks forward to including urban tree cover in a more substantial way in our air quality plans.”


Protecting and expanding tree cover goes beyond air quality benefits, including opportunities for recreation, wildlife habitat, flood control, and reaching the water quality goals that are the focus of the Chesapeake Bay Program, a federal state partnership to protect and restore the Chesapeake Bay.


“Trees and forests provide a multitude of ecological services. Forests are the best land cover for water quality: protecting and expanding trees and forests is critical to restoring the Chesapeake Bay. Trees also help sequester carbon, improve fisheries, stabilize stream banks, control erosion, and reduce the velocity of damaging runoff,” noted Nicolas DiPasquale, Director of the US EPA Chesapeake Bay Program.


To download the original press release and associated data, click here.



About the Center for Chesapeake Communities (

The Center for Chesapeake Communities works to assist local governments in their efforts to plan for growth and development and the protection of their own natural resources and the Chesapeake Bay.

Providing tools, techniques, and technical assistance opportunities, the Center supports local government watershed initiatives. The Center addresses concerns of jurisdictions that are large or small, rural or urban, developed or developing. It is committed to informing, educating, training, and assisting local governments in the protection of local natural resources and the Chesapeake Bay.


About the Pinchot Institute for Conservation (

The mission of the Pinchot Institute is to strengthen forest conservation thought, policy and action by developing innovative, practical, and broadly‐supported solutions to conservation challenges and opportunities. Pinchot Institute accomplishes this through nonpartisan research, education and technical assistance on key issues influencing the future of conservation and sustainable natural resource management.