IMPROVE Visibility Monitoring Program

A nationwide cooperative visibility monitoring effort is being accomplished through the Interagency Monitoring of Protected Visual Environments (IMPROVE) program. The IMPROVE Program is a cooperative measurement effort governed by a steering committee composed of representatives from Federal and regional-state organizations. The IMPROVE monitoring program was established in 1985 to aid the creation of Federal and state implementation plans for the protection of visibility in Class I Federal areas (156 national parks and wilderness areas) as stipulated by the 1977 amendments to the Clean Air Act.

Yellowstone National Park

The objectives of IMPROVE are:

1) to establish current visibility and aerosol conditions in mandatory Class I Federal areas

2) to identify chemical species and emission sources responsible for existing man-made visibility impairment

3) to document long-term trends for assessing progress towards the national visibility goal

4) and with the enactment of the Regional Haze Rule, to provide regional haze monitoring representing all visibility-protected federal class I areas where practical

IMPROVE has also been a key participant in visibility-related research, including the advancement of monitoring instrumentation, analysis techniques, visibility modeling, policy formulation, and source attribution field studies.

The IMPROVE program includes Class I visibility characterization by scene monitoring with automated cameras, the measurement of optical extinction with transmissometers, and the measurement of the composition and concentration of the particles that produce the extinction with aerosol monitors.

The IMPROVE network began in 1988 with 42 sites, mostly at or near Class I visibility areas. This slowly grew to 80 sites in the late 1990’s. In 2000 and 2001, the network was expanded to 144 sites. Of these, 110 are IMPROVE sites, to officially represent 155 Class I Federal areas. An additional 34 sites are IMPROVE Protocol, operated for Federal Land Managers, states and tribes. Starting in 2002, 18 new sites were installed as IMPROVE Protocol, operated for states and tribes. Operationally, there is no difference between IMPROVE and IMPROVE Protocol sites.

There are six IMPROVE program sites in Wyoming, to characterize visibility conditions in Class I areas. The monitoring stations are located near the Bridger Wilderness, North Absaroka Wilderness, in Yellowstone National Park, at Brooklyn Lake, near Cloud Peak Wilderness and in Thunder Basin National Grasslands. The Bridger Wilderness and Yellowstone National Park sites have collected data since 1988, at Brooklyn Lake since 1993, and the North Absaroka Wilderness site was installed in 2000. The Thunder Basin and Cloud Peak monitors became part of the IMPROVE Network in July 2002. The photo below shows the IMPROVE monitor at the top of Dead Indian Pass near the North Absaroka Wilderness Area.

IMPROVE Monitoring Station