Page 1-8 
Ventilation Design Handbook on Animal Research Facilities Using Static Microisolators 
Scott Perkins and Neil S. Lipman: Characterization And Quantification Of Microenvironmental 
Contaminants In Isolator Cages With A Variety Of Contact Beddings, 1995, Contemp. Topics 
Lab. Anim. Sci., 173:96-113. 
Microenvironmental contaminants were measured within isolator-type cages housing 
DBA/1J mice on eight contact beddings. Each cage contained 850 cm 3 of bedding and 
five mice randomized by body weight. Seven cages with and two to four cages without 
mice were evaluated per bedding. Macroenvironmental conditions were defined and 
controlled. Macro- and microenvironmental temperatures, relative humidity, and carbon 
dioxide and ammonia concentrations were determined daily during each of three 7-day 
test periods. An air sampling pump and detector tubes were used to measure hydrogen 
gas, 
2-butanol, acetone, ethanol, carbon monoxide, acetic acid, hydrogen sulfide, sulfur 
dioxide, and formaldehyde on the final day of each test period. In addition, gas 
chromatographic analysis was used on the seventh day to detect additional volatile 
alcohols and ketones. Ammonia concentrations ranged from 0 to 410 ppm, depending on 
the bedding type and day of measurement. On the basis of the mean microenvironmental 
ammonia concentration in the cages with mice, the beddings were ranked from highest to 
lowest in ammonia generated, as follows: aspen shavings, pine shavings, reclaimed wood 
pulp bedding, virgin pulp loose bedding, hardwood chip bedding, recycled paper bedding, 
virgin cellulose pelleted bedding, and com cob bedding. The temperature, relative 
humidity, and carbon dioxide concentration were similar among beddings. No other 
contaminants were detected except acetic acid (mean = 0.86 ppm) in the cages with and 
without mice containing corncob bedding. Sulfur dioxide (mean = 0.42 ppm) was only 
detected in cages with mice and corncob bedding. In summary, the concentration of 
ammonia generated varied significantly in cages containing mice and different contact 
bedding. 
• Temperature: There were no significant differences in temperature detected among 
cages with mice and various bedding throughout the 7-day observation periods. 
Temperature rise in the cages with hardwood chip bedding was approximately 4 °F. 
® Relative humidity: Intracage relative humidities were not significantly different 
among cages with different bedding through the 7-day observation periods. Relative 
humidity rise in the cages with hardwood chip bedding was approximately 25 percent. 
• Carbon dioxide: There were no significant variations detected in carbon dioxide 
concentration among cages with various bedding throughout the 7-day observation 
periods. Carbon dioxide concentration in the cages with hardwood chip bedding was 
approximately 4,500 ppm with background concentration of 370 ppm. 
