Passive monitors to measure hydrogen sulfide near concentrated animal feeding operations

Abstract

Hydrogen sulfide (H 2 S) is one of many airborne pollutants emitted by concentrated animal feeding operations (CAFOs). However, few studies have characterized ambient H 2 S levels near these facilities, largely due to the lack of low-cost, reliable, and easily transportable instrumentation available to researchers. We determined intermediate environmental H 2 S exposure near CAFOs using Radiello passive monitors. First, a laboratory study was performed to determine the accuracy of the device. Next, a total of eight passive H 2 S monitors were deployed bi-weekly in close proximity (<40 m) to a medium-sized swine confinement for seven months in order to determine the temporal and spatial variability of H 2 S. Finally, we measured H 2 S concentrations across two rural Iowa counties to characterize ambient exposure near thirteen CAFOs and two schools. The value of the temperature-adjusted H 2 S passive diffusion rate provided by the supplier was 29% larger than the 24 h rate determined experimentally. Concentrations of H 2 S measured near the medium-sized confinement were varied and ranged from 0.2 to 48.6 ppb depending on the sampling period and proximity to a lagoon on the property. Two-week concentrations near the schools were low (<1 ppb), while concentrations near the thirteen CAFOs ranged from 0.1 to 42.9 ppb. The passive monitors were effective in measuring H 2 S concentrations near a swine CAFO as long as they were exposed for a sufficient period of time (two weeks). Radiello passive monitors are a promising new device in measuring intermediate H 2 S exposure in rural populations. Measured values in excess of an Iowa state limit of 30 ppb (24 h average) suggest that enforcement actions are needed to mitigate H 2 S migration from swine CAFOs. © The Royal Society of Chemistry.