Hydrogen sulfide concentrations at three middle schools near industrial livestock facilities

Safe school environments are essential for healthy development, yet some schools are near large-scale livestock facilities that emit air pollution. Hydrogen sulfide (H₂S) from decomposing manure is an indicator of livestock-related air pollution. We measured outdoor concentrations of H₂S at three public middle schools near livestock facilities in North Carolina. We used circular graphs to relate H₂S detection and wind direction to geospatial distributions of nearby livestock barns. We also used logistic and linear regression to model H₂S in relation to upwind, distance-weighted livestock barn area. Circular graphs suggested an association between upwind livestock barns and H₂S detection. The log-odds of H₂S detection per 1000 m² increased with upwind weighted swine barn area (School A: β-coefficient (β)=0.43, SE=0.06; School B: β=0.64, SE=0.24) and upwind weighted poultry barn area (School A: β=0.05, SE=0.01), with stronger associations during periods of atmospheric stability than atmospheric instability (School A stable: β=0.69, SE=0.11; School A unstable: β=0.32, SE=0.09). H₂S concentration also increased linearly with upwind swine barn area, with greater increases during stable atmospheric conditions (stable: β=0.16 parts per billion (p.p.b.), SE=0.01; unstable: β=0.05 p.p.b., SE=0.01). Off-site migration of pollutants from industrial livestock operations can decrease air quality at nearby schools.