AIRBORNE DUST AND AEROALLERGEN CONCENTRATION IN A HORSE STABLE UNDER 2 DIFFERENT MANAGEMENT-SYSTEMS

Airborne dust concentration (ADC) was measured in 2 different horse ma nagement systems using an Andersen cascade impactor in the box-stall, and a personal Marple cascade impactor attached to the halter to measu re ADC in the breathing zone. The levels of aeroallergens implicated i n chronic obstructive pulmonary disease were measured by radioallergos orbent-inhibition immunoassay. A conventional management system (Syste m C) utilising hay feed and straw bedding, and a recommended environme nt (System R) utilising wood shaving bedding and a complete pelleted d iet were studied. In the stall, total and respirable ADC (geometric me an) were significantly higher in System C (2.55 mg/m3; 0.44 mg/m3, res pectively) than in System R (0.70 mg/m3; 0.20 mg/m3, respectively). In System C, the total and respirable ADC in the breathing zone (17.51 m g/m3; 9.28 mg/m3) were much higher than in the stall, but values in bo th regions were similar in System R (0.52 mg/m3; 0.30 mg/ml). Major ae roallergens were significantly higher in System C than in System R: Mi cropolyspora faeni (1423 ng/m3 and 705 ng/m3), Aspergillus fumigatus ( 1823 ng/m3 and 748 ng/m3), and mite allergens (1420 ng/M3 and 761 ng/m 3). Measurement of ADC with personal samplers indicates that the very high inhalation challenge in the breathing zone is not reflected in me asurements of stall air quality. When compared with System C, System R produced only 3% of the respirable dust burden in the breathing zone and a decreased aeroallergen challenge.