National Park Service

Northeast Temperate Network (NETN)

Parks in this Network

NETN Network Map
Click to see Larger
Network Map
Find your park logo
A hazy view of the Boston skyline as seen fron Boston Harbor Islands NRA.
A hazy view of the Boston skyline as seen fron Boston Harbor Islands NRA. Doc Searles photo.
  • Determine trends in ozone levels, the the impacts of ozone pollution on selected bioindicator species, and changes in the deposition of pollutants.



Download Program Brief:

forest health brief

Atmospheric deposition is the process by which airborne particles and gases are deposited to the earth's surface either through precipitation (rain, snow, clouds, and fog) or as a result of complex atmospheric processes such as settling, impaction, and adsorption, known as dry deposition. Deposition can include a wide variety of natural and anthropogenic pollutants, including inorganic elements and compounds (e.g., nitrogen, sulfur, basic cations, mercury and other metals) and organic compounds (e.g., pesticides and herbicides). Once deposited, pollutants can have a variety of ecosystem effects. Nitrogen and sulfur compounds, for example, can result in acidification of freshwaters, loss of aquatic species, eutrophication of estuarine and near-coastal waterways, soil nutrient and base cation leaching, and vegetation changes. The NPS is responsible for the protection and conservation of the areas it manages in order to "leave them unimpaired for the enjoyment of future generations". NPS also has an affirmative responsibility under the Clean Air Act to protect parks and their resources from sources of air pollution and to participate in national and regional initiatives to control air pollution. Protecting resources in our national parks from air pollution requires extensive knowledge about the origin, transport, and transformation of pollutants and the ecological effects that may result. The NPS Air Resources Division has taken the lead on air resource monitoring and reporting. Refer to their website for the latest reports and information.

A.T. Deposition Effects Study

High elevation and ridge-top ecosystems along the Appalachian Trail corridor are very sensitive to acidic deposition. Air pollutants emitted by power plants, industry, vehicles, and agriculture can contribute to acidic deposition to forests, soils, streams, and lakes. Effects include forest die-back and streams that are no longer able to support certain sensitive species of fish. The AT MEGA-Transect Deposition Effects study will evaluate the condition and sensitivity of the Trail with respect to acidic deposition by investigating current impacts and identifying deposition "critical loads" (the amount of acidic deposition below which deleterious effects are not expected). The study will also predict the time needed for ecosystem recovery under future deposition scenarios. The project is led by scientists from US Geological Survey (USGS), USDA Forest Service (USFS), universities, and private companies, and is began in the spring of 2010.


Key objectives include the development and refinement of thresholds for ecosystem effects from acid deposition, and the development of critical loads for acid deposition. Identifying ecological threshold values that are specific to AT soils, forests, and streams will result in more accurate critical loads, allowing for improved assessments of current and future ecosystem health. Defining critical loads will also enable NPS to set meaningful air quality management goals to ensure protection of the AT.


The AT MEGA Transect Deposition Effects study is supported by funds provided to the National Park Service (NPS) by American Electric Power (AEP), an operator of coal-fired power plants in the Ohio Valley. In 2008, AEP made a donation to NPS for the restoration of land, watersheds, vegetation, and forests affected by air pollution emitted by AEP power plants. The regional scope of the AT MEGA Deposition Effects study includes affected Class I air quality areas, including Shenandoah and Great Smoky Mountains National Parks, and surrounding national forests. Additional park-specific AEP projects will target local issues related to ecosystem restoration and pollution control or prevention.


This study will identify and assess acid deposition-sensitive ecosystems along the AT.  Information from the study will be used by the NPS to develop air quality management goals for the long-term protection of the AT. Outreach efforts will promote awareness and understanding of the deleterious effects of acidic deposition to state and federal air quality management agencies, scientific forums and the stakeholder community. The study will also provide information to allow the assessment of the  success of current air quality improvement strategies. The AT MEGA-Transect Deposition Effects Study also demonstrates the value of the AT for monitoring environmental change across a large geographic region, supporting an ongoing  multi-agency initiative with professional and citizen scientists that includes the NPS, USFS, USGS, and the non-profit Appalachian Trail Conservancy.


The project plans a three-tiered sampling approach with various levels of sampling intensity: 12 Level I sites (most intensive), 50 Level II sites, and 200 Level III sites. Level I sites will include sampling of: (1) atmospheric deposition, (2) soil chemistry, (3) water chemistry, (4) wood tissue chemistry, (5) tree ring cores to assess growth, and (6) composition of understory vegetation. Level II sites will focus on soil and water chemistry samples; Level III sites will sample water chemistry only. Citizen scientist volunteers will be utilized to assist with data collection efforts.

NETN Air Quality Monitoring Materials

Air Atlas - Estimated Atmospheric Deposition from ARD website

Click the map legend to turn parks, monitors, or atmospheric deposition layers on and off. Click on parks on the map to find park specific estimates. Wet deposition estimates are based on air quality data from monitors in the National Atmospheric Deposition Program (NADP) network.

Northeast Temperate Network Staff Contacts for Breedinf Landbird Monitoring

Name Title/Position Phone Number Email Address
Aaron Weed Program Manager 802-457-3368
ex. 237
Fred Dieffenbach Environmental Monitoring Coordinator - Appalachian NST 802-457-3368 ex 236
Holly Salazer Northeast Region ARD 814-865-3100
Adam Kozlowski Data Manager 802-457-3368 ex 240
Ed Sharron Science Communication Specialist 802-457-3368 ex 223
Last Updated: December 30, 2016 Contact Webmaster