Air Quality Monitoring & Access to Data

The National Park Service Air Resources Division administers an extensive Air Monitoring Program that measures air pollution levels in national parks. The purpose of the Program is to establish current air quality conditions and to assess long-term trends of air pollutants that affect park resources. The data are also used to determine compliance with the National Ambient Air Quality Standards and to assess national and regional air pollution control policies. Measuring air pollution levels in parks is an essential part of the NPS air resource management program and provides vital information to Congress, air pollution control agencies, academia, and the public.

The NPS Air Monitoring Program consists of an extensive network of air monitoring stations in almost 70 national parks across the country. Several of these sites have been in operation for over 20 years. The Program has three primary components: visibility, gaseous pollutants (mainly ozone), and atmospheric deposition (wet and dry). Meteorological monitoring is also conducted at many locations to aid in the interpretation of measured air pollution levels. For more information, please see the table below.

Air Monitoring Programs	Visibility IMPROVE at Big Bend NP, TX	Ozone & Meteorology GPMN at Shenandoah NP, VA	Wet & Dry Deposition NADP at Virgin Islands NP, VI
Network Names	IMPROVE (Interagency Monitoring of Protected Visual Environments)	GPMN (Gaseous Pollutant Monitoring Network) CASTNET (Clean Air Status and Trends Network)	NADP (National Atmospheric Deposition Program) CASTNet (Clean Air Status and Trends Network)
Parameters Measured	fine and coarse particle (PM2.5 & PM10) mass, elements, sulfate, nitrate, organic and elemental carbon scenic views, scattering, and absorption	ozone, wind speed, wind direction, ambient temperature, relative humidity, solar radiation, wetness	Wet: sulfate, nitrate, ammonium, cations, and mercury in precipitation Dry: sulfur dioxide, sulfate, nitric acid, nitrate, and ammonium; wind speed, wind direction, ambient temperature, relative humidity, solar radiation, wetness
Frequency of Measurements	24-hrs every 3 days	continuous, hourly averages	weekly
Access to Data	Visibility Data	Ozone & Met Data	Wet Deposition Data Dry Deposition Data

In addition to long-term monitoring, the NPS is involved in many special studies that tend to be short-term and more intensive in nature. These studies are often initiated to answer specific local and regional research questions, such as identifying sources of air pollution or assessing the potential risk of natural resources in parks.

Locations

The Air Resources Division monitors air quality in cooperation with several national networks. This monitoring complements the efforts of other federal, state, and local agencies. The following map shows where different monitors are located within the national park system. Links below the map provide site location information for each monitoring network.

Visibility | Ozone | Deposition | Meteorology | All

Trends

Assessing how air quality is changing is a prime function of the NPS Air Monitoring Program. In fact, the National Park Service measures the success of its air resource management program based on results achieved, even though the NPS has no authority to regulate sources of air pollution located outside park boundaries. Monitoring data on visibility, ozone, and atmospheric deposition show that air pollution is affecting some park resources nationwide. Consistent with the Government Performance and Results Act, the NPS has established the air quality goal of stable or improved air quality in 70% of reporting park areas by September 30, 2008. An area meets the goal if it does not show statistically significant deterioration in any of the performance indicators. For more information, view the 2005 GPRA Report (PDF 0.8 mb). Based on the latest analysis of air quality data covering the period 1995-2004, 68% of reporting parks had stable or improved air quality. In addition,

• All 30 reporting parks showed stable or improving visibility on both the clean and hazy days.
• Of the areas monitoring wet deposition, 93% showed stable or improving trends in sulfate concentrations in precipitation (27 of 29 parks reporting); 83% in nitrate concentrations (24 of 29 parks reporting); and 76% in ammonium concentrations (22 of 29 parks reporting).
• Of the 32 park units that monitor ozone, 20 units or 63% have stable or improving trends.