MEASUREMENT OF RESPIRABLE DUST LEVELS IN HORSE STABLES

Respirable dust levels were monitored at two different stable complexe s. Monitoring of air inside the stables and the outside incoming air w as carried out at least once every hour for periods of one week. The r espirable dust levels showed a large fluctuation of 0.4 to 305 counts/ mL. The highest level recorded (305 counts/mL) was for a sampling poin t outside the horse stable which may have been a result of the stables proximity to a hay barn and a manure storage area. The high outside l evels of respirable dust may have been due to the location of the samp ling point in a position that recorded exhaust air rather than inlet a ir as it may have been located in the wake of the building. Diurnal va riation covered a range of approximately 10 counts/mL to 95 counts/mL within a 24 hour period. Seasonal variation at the same location indic ated a higher level during the winter period than during the summer pe riod. High levels of respirable dust were recorded outside the mill bu ilding (maximum 148.8 counts/mL) which was part of one of the stable c omplexes and also outside the dwelling house (maximum 128.3 counts/mL) approximately 50 m from the main stable complex. Natural ventilation was the system of ventilation used in all of the stables monitored. Th e data recorded indicate that natural ventilation may not be relied up on to achieve the current recommended internal dust quality within the stable at all times or that the natural ventilation system used in th e stables surveyed was not adequate.