Air quality at low outdoor temperatures in Norwegian horsestables

摘要

The aim of this study was to investigate the variation in air quality on days with low outdoor air temperature in Norwegian horse stables. A total of 19 insulated, mechanically-ventilated stables with horses kept inside during the nigi were included in the study. In almost all of the stables (n=18) ventilation fans were operated during the night. In eleven < the stables the exhaust fans had a manual step by step regulation whereas in the remaining eight stables the exhaust far were regulated by a temperature-setpoirtt thermostat. Fresh air inlets however, were highly variable in design an management leading to potential for ineffectiveness of ventilation functions. In four of the stables there were no specific a inlet systems, in five stables the exit door was used as the only air inlet. Mean outside air temperature was 0.0 ± 0.8 °C an mean indoor air temperature was 7.5 ±0.5 °C. Mean level of CO2 was 1800ppm and only in one stable CO2 exceeded 30C ppm. Mean inside ammonia (NH3) was 1.3 ppm andonly in one stable the level ofNH3 exceeded 5 ppm. The total du concentration was 0.69 ± 0.19 mg/m3 and in two stables the dust concentration exceeded 1.0 mg/m3. Half of the stablt visited had a lower calculated air exchange rate than recommended. Still, the majority of the stables maintained acceptab, air quality, with ammonia and dust levels within recommended levels.