Scenic vistas are diminished by haze that causes discoloration, loss of texture, and diminished visual range, and some of the pollutants that form haze have been linked to serious health effects and environmental damage. These reports summarize visibility in Class I areas that are protected and regulated by the Regional Haze Rule.

Elevated ozone concentrations adversely affect sensitive vegetation and ecosystems, including forests, parks, wildlife refuges, and wilderness areas. This graphical report summarizes ozone trends as measured by the EPA ozone monitoring network.

Deposition of sulfur and nitrogen compounds contributes to the acidification and eutrophication of sensitive terrestrial and aquatic ecosystems. This graphical report summarizes trends in wet deposition data from the NADP National Trends Network (NTN).

About half of the acidity in the atmosphere falls back to earth through dry deposition. This graphical report summarizes the sulfur and nitrogen composition of dry deposition data from the EPA's Clean Air Status and Trends Network (CASTNet).

Use a variety of interactive tools and applications to visualize, explore, filter, and download raw and aggregated air quality data and relevant metadata from the integrated database in a variety of customizable formats.

These express tools provide access to the full collection of data and metadata from the Interagency Monitoring of Protected Visual Environments (IMPROVE) program. The IMPROVE program monitors pollutants and generates metrics to identify sources and causes of regional haze at all Class 1 Areas in the U.S.

Explore air-quality-related water chemistry data collected and managed by the U.S. Forest Service. These data have been collected on Forest Service lands or by the Forest Service on adjacent lands, and are used to help assess air pollution impacts to sensitive waters in Federally-protected areas.

View the locations of monitoring sites and explore monitoring site metadata for all of the available ground-based monitoring networks in the FED database using an interactive map.

Search and explore the entire collection of air and water quality datasets currently stored in the FED database. See details for each dataset such as the parameters it contains, the data flags used, and its monitoring site locations on a map.

View low-level and comprehensive details about each dataset stored in the FED database. Download each dataset's raw data, see its monitoring locations on a map, and view details about the parameters it contains.

These express tools provide access to detailed metadata about datasets, networks, sites, parameters, methodologies, data flags, agencies, and other key entities that are referenced by the data products and air quality datasets provided on the FED website.

An Air Quality Related Value (AQRV) is a scenic, cultural, physical, biological, ecological, and/or recreational resource in one or more federal areas that may be adversely affected by a change in air quality. These express tools help analyze the impacts to AQRVs for Federal Class I Areas.

This interactive tool provides access to data and charts based upon the EPA Annual Summary dataset, which is a compilation of annual averages and other metrics for the pollutants submitted to the EPA Air Quality System (AQS). It includes criteria air pollutants (CAPs), hazardous air pollutants (HAPs), urban air toxics, fine (PM2.5) aerosols, and other pollutants that affect visibility and air quality.

These express tools below provide a variety of charts and graphs for analyzing Regional Haze Rule (RHR) metrics from the IMPROVE program. The IMPROVE program monitors pollutants and generates metrics to identify sources and causes of regional haze at all Class 1 Areas in the U.S.

The tools below provide a variety of graphical products for exploring and analyzing raw aerosol data from the IMPROVE network. The tools are designed to facilitate quick, high-level assessments of raw IMPROVE aerosol data at the network, regional, and individual monitoring site level.

This graphical and tabular report summarizes the 5-year and by-year average 4th Highest Daily 8-hr Avg. Max. Ozone Concentrations at EPA ozone sites. A time series graph and data table are displayed.

This graphical and tabular report summarizes the 5-year and by-year average W126 Ozone Exposure Indexes at EPA ozone sites. A time series graph and data table are displayed.

These webcams are useful for seeing the effects of air pollution on visibility. Take note of whether or not it appears that air pollution is affecting the quality of the respective vistas.

Cameras are used at a number of IMPROVE monitoring sites. Images from monitoring sites with over five years of data were selected to capture the range or "spectrum" of visual conditions at each site.