Abstract
Concentrations of ammonia, volatile organic compounds, particles, and mouse allergen were measured in an animal facility. Ammonia concentrations averaged less than 1 ppm, below any health–based standards. The concentrations of volatile organic compounds were in the 5–15 µg/m3 range. Among the volatile organic compounds found, only the terpenes a–pinene and a–terpinol (which may be derived from the pine shavings used as bedding) were consistently present in concentrations greater than outdoor air. The primary air contaminant present at concentrations high enough to be of known physiological significance was the mouse allergen, Mus ml. To determine which activities in an animal room generated the highest concentrations of airborne Mus ml, a monitor that counted particles continuously was used. The particle counts were correlated with allergen levels in the worker's breathing zone (r50.83, p,0.05). Thus, a particle counter can be used effectively in an animal facility to identify specific activities that generate high levels of both particles and allergen. Such activities included changing mice from soiled to clean cages, cleaning floors, and changing foam inserts in pressurized individually ventilated cages. To reduce exposure to allergen during cage changing, which is the major activity for an animal caretaker, a capture–type ventilated changing table was designed and tested. Use of such a table reduced exposure to allergen in the worker's breathing zone from 4.9 6 1.1 to 2.1 6 0.3 ng Mus ml/m3, a level comparable to background levels.