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Media Advisory: DRI scientists deploy new tethered helium balloons to aid probe of Las Vegas air quality


Reporters and Editors, Please Note

WHO: Desert Research Institute and the National Oceanic and Atmospheric Administration (NOAA) in cooperation with the Clark County Department of Air Quality and Environmental Management (DAQEM) and the U.S. Environmental Protection Agency

Conducting an upper-atmospheric air quality study to investigate sources of ozone and factors leading to increased levels in the Las Vegas Valley using a new tethersonde system, or tethered helium-filled balloons

WHERE: Jean Airport

WHEN: Wed., Aug. 10, in collaboration with the Clark County DAQEM's ozone sampling media event with glider planes. DRI scientist Dr. Dave DuBois will be launching a balloon at 8 a.m. and will be available to speak with media beforehand, during or after the launches.

HOW: The Jean Airport portion of the study on Wednesday will utilize a newly acquired tethersonde system consisting of meteorological sensor packages suspended below a large, tethered helium-filled balloon, which provides the lift to raise the instruments up to 3000 meters above ground level. The system gives the research meteorologist a detailed profile of the atmospheric boundary layer by raising and lowering the tethersondes to measure atmospheric conditions over time at multiple levels. The tetherline is controlled by a winch to raise or lower the instruments as they collect continuous vertical measurements of wind speed and direction, temperature, relative humidity and ozone level. It is suspected that on occasion, high levels of ozone in the upper atmosphere are vertically mixed to the ground level in the Las Vegas area thus resulting in higher ozone pollution. This system will aid DRI and NOAA researchers in understanding the vertical air-mixing process and identifying the source of ozone.

The overall study incorporates an extensive array of atmospheric testing equipment, including one radar (radio detection and ranging) wind profiler and four SODAR (sonic detection and ranging) systems, which were deployed at the beginning of the 2005 ozone season. The radar wind profiler was set up in the central portion of the Las Vegas Valley and collocated with a "mini-SODAR" to improve definition of wind patterns at lower levels (less than 150 meters). To aid in defining ozone-transport pathways in an out of the area, the other three SODARs were placed in Jean, Nev. (southwest of Las Vegas), the Las Vegas Motor Speedway (northeast of Las Vegas) and at the Floyd Lamb State Park in the northwestern portion of Las Vegas.

It's no surprise that ozone pollution in urban Las Vegas has become a major focus for local governmental air-quality agencies, since the EPA officially designated the city non-compliant for ozone in Sept., 2004. To remediate high episodes of local ozone, the Clark County DAQEM and the EPA have turned to Desert Research Institute scientists through its Cooperative Institute for Atmospheric Sciences and Terrestrial Applications, or CIASTA, to conduct an upper-atmospheric air quality study to investigate the sources of ozone and factors leading to increased levels in the Las Vegas Valley. An interdisciplinary research collaboration among NOAA and educational institutions within the Nevada System of Higher Education, CIASTA consists of research meteorologists and air quality scientists well-experienced in sleuthing for air-quality troublemakers.

Ozone occurs naturally in the upper atmosphere and protects the earth from ultraviolet rays. At ground level, however, ozone is a constituent of smog caused when sunlight, hot temperatures and various pollutants combine in a complex chemical reaction. Even in low concentrations, ground-level ozone may irritate the human respiratory system and inflame the lining of the lungs. Based on national ambient air quality standards--established by the EPA--Las Vegas and several surrounding areas have been designated non-attainment for the 8-hour average ozone level.

Ozone seasons vary around the United States, but in Clark County, ozone usually registers the highest between May and August. The study period for this project correlates with the typical Clark County ozone season with the project beginning in May 2005 and concluding in August 2005. Drs. Mark Green and Dave DuBois--co-principal investigators with DRI--and researchers with NOAA's Las Vegas-based Air Resources Laboratory are collaborating on this air-quality study. A major goal is to expand knowledge of upper-air wind patterns and illuminate transport processes that carry ozone into, around and out of the Las Vegas area.

Upper-air measurements have indicated that elevated levels of ozone in the Las Vegas area may be resulting partially from wind currents carrying ozone to Nevada from southern California. DRI and NOAA researchers are aiming to define the effect that this process exerts on ozone levels in urban Las Vegas. In the analysis and evaluation stages of the study, air-emissions, atmospheric chemistry and meteorological data will be combined to establish robust conceptual models. These models, in turn, will be used to evaluate measures for reducing ozone levels in metropolitan Las Vegas.