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Enhanced Field Experiments

Big Bend Regional Aerosol and Visibility Observational Study (BRAVO)

The BRAVO study was conducted to investigate the causes of haze at Big Bend National Park. The network operated from July to October 1999 measuring fine aerosol mass and its constituents, atmospheric optical properties, gaseous air pollutants and meteorology at Big Bend National Park. Some additional information is available from the IMPROVE website.

Southeastern Aerosol and Visibility Study (SEAVS)

SEAVS measured aerosols under humid Southeastern US conditions to determine the contribution of major aerosol constituents, including water, to the total particle mass and light extinction. Field measurements included particle size, water and optics, aerosol composition, meteorology and human perception of scenes at the Great Smoky Mountains National Park over a 6 week period during the summer of 1995.

Measurement of Haze and Visual Effects (MOHAVE)

The MOHAVE network was established to help determine the contributions of the Mohave Power Plant and other sources to haze at Class I areas in the Southwestern US. The MOHAVE network employed 43 IMPROVE type samplers in the Southwest collecting daily particulate samples over a 24 hour period. The network collected data over a winter and summer period from 1/10/-2/15/92 and 7/11/-9/2/92 respectively. The particulate samples were analyzed for PM2.5 and its elemental constituents, organics, ions, light absorption and PM10.

The Pacific Northwest Regional Visibility Experiment Using Natural Tracers (PREVENT)

The PREVENT network was established to study visibility causes and effects in Washington state, west of the Cascades. The network consisted of 34 monitors located in Washington and Oregon. Daily particulate samples were collected from 6/90-9/90 and analyzed for PM2.5 mass and its elemental constituents and light absorption.

The Winter Haze Intensive Tracer Experiment (WHITEX)

WHITEX was established to study the visibility impacts of emissions from the Navajo Generating Station. The database contains data from 13 locations which sampled from 1/1/87 - 2/18/87. Samples were collected every 6, 12, and 24 hours depending on the site and sampler. The particulate samples were analyzed for PM2.5 mass and its elemental constituents, organics, ions, and light absorption.

Yosemite NP Aerosol and Visibility Study

During the late summer and fall Yosemite National Park experiences some of the highest organic mass concentrations of any national park in the United States, and, on a fractional basis, carbonaceous particles are the single largest contributor to visibility impairment. Over a period of several weeks in late summer and fall of 2002 a special study was conducted to investigate the origins and physical/optical characteristics of this carbon aerosol.


updated on 03/05/2006  I   http://nature.nps.gov/air/studies/vis_fieldxpt.cfm   I  Email: Webmaster