Cherokee Nation collects air toxics samples at the Pryor site in Mayes County. During these studies Cherokee Nation Clean Air Program staff collect VOC samples every sixth day in specially treated canisters for a 24-hour sample period utilizing a commercially available canister sampling system, and deliver the exposed canister to an appropriate laboratory for analysis. The Cherokee Nation will analyze the lab data, identifying VOCs detected in project samples, checking the lab’s detection limits for those VOCs, and then compare the data to EPA human health benchmarks and ODEQ MAACs. Data is compared to EPA’s TRI inventory, Oklahoma’s TRI inventory, and to wind rose diagrams provided by the Oklahoma Climatological Survey in an attempt to identify industrial sources of detected VOCs. Air Toxics data will soon be uploaded to EPA’s AQS database.
In 2004 Cherokee Nation partnered with CENSARA-CENRAP Regional Planning Organization (RPO) on the aforementioned ammonia study. Eight ammonia denuder samplers were installed across the Midwest to detect ammonia. Pictured below is the ammonia denuder sampler and corresponding denuders. The ammonia sampling network operates on a one in six day sampling schedule similar to the PM2.5 networks.
Collocated with the denuder sampling apparatus is a Pranalytica Nitrolux continuous ammonia analyzer. Pranalytica has developed instrumentation for highly sensitive laser spectroscopy for detection of trace gases in medical, environmental, industrial, and national security applications. Laser spectroscopy has been extensively used for detection of a large number of industrially produced pollutant gases such as NO, NO2 , NH3 , SO2 , and CH4. Many of these gases are found in large concentrations at their sources, e.g. nitric oxide at the tailpipe of an automobile, and at very low concentrations in the ambient atmosphere and stratosphere. Optical absorptivity of most gases is characterized through the measurements of a sample of known concentration. With this in hand, the concentration of an unknown sample of ammonia may be readily determined.
The Nitrolux is an ultra-sensitive reference instrument capable of detecting trace concentrations of ammonia in air. The Nitrolux can detect ammonia pollution in the parts per billion (ppb). The Nitrolux and denuder sampler is located at the Stilwell CastNet site. For more information on regional haze and visibility projects please visit CENRAP.