New Protocol for the Determination of Reactive Organic Gases in Animal Feeding Operations

A new protocol was used to measure the quantity of reactive organic gases (ROG) being emitted from animal feeding operations (AFO) such as feed yards, dairies and poultry houses. The protocol makes use of a portable gas chromatograph (GC) that is brought to the field where actual measurements are taken in conjunction with the EPA flux chamber sampling protocol. To have the analyte concentrations come within the detection limits of the instrument, the GC is equipped with an EPA TO-14 purge and trap pre-concentration device that can introduce gas samples at a rate of 100ml/min. Once the analytes are trapped, they are desorbed and directed to the column for immediate separation. Installed were two traps, a carbosieve trap sensitive to highly volatile compounds and the Tenax GR trap sensitive to most other hydrocarbons. Two columns were also used to separate polar and non-polar substances. In addition, two detectors a photo ionization detector (PID) for molecules with carbon double bonds and aromatics and a flame ionization detector (FID) to detect most other hydrocarbons, were installed. With this setup, flux and emission factors for ROGs from ground level area sources can be estimated more readily. This method eliminates problems associated with the use of Tedlar bags and gas canisters. This paper presents preliminary results on the appropriateness of methods used to determine ROG fluxes, emission rates and emission factors from ground level areas sources.