Evaluation of ambient level hydrogen sulfide and ammonia static samples using commercially available sampling media

Abstract

<p>A suitable container and sampling method for the collection of hydrogen sulfide and ammonia at low concentrations present in ambient air needs to be examined due to the concern that air emissions from animal feeding operations (AFOs) are an environmental hazard and a potential human health issue. Tedlar bags with polypropylene fittings, Restek SilcoCan canisters, and Melinex bags with polypropylene fittings were investigated as sampling media for hydrogen sulfide and ammonia at ambient-level concentrations. The samples were tested at various known ambient-level concentrations at 0, 12, and 24 hour intervals. A combined sampling system for ammonia and hydrogen sulfide in which all aspects of the experiment could be carried out with minimal changes was developed. A SO2 fluorescent based analyzer and a chemiluminescent based NO/NO2/NO[subscript x] analyzer were used for sample analysis. The Tedlar bag with polypropylene fittings was proven to be the best suitable container for hydrogen sulfide for both short and long-term stability at ambient level concentrations up to 75 ppb and holding times up to 24 hours. The Melinex and the Restek SilcoCan canister were also found to be suitable for hydrogen sulfide sampling for sample concentrations up to 40 ppb and holding times up to 24 hours. The 0 hour holding time at a sample concentration of 75 ppb for Melinex and the Restek SilcoCan canister was also found to be suitable for the collection of hydrogen sulfide, but the 12 and 24 hour were not. The Restek SilcoCan canister was found to be suitable for the collection of ammonia for ambient level concentrations up to 131 ppb and for holding times up to 24 hours. Melinex was found to be suitable up to ambient level concentrations of 131 ppb for a 0 hour holding time for ammonia while Tedlar was found to be unsuitable sampling media for the analysis of ambient level ammonia concentrations.</p>