1. Indoor Air Quality Testing with an Andersen N6 Microbial Impactor Kit
John Kanzia
Environmental Quality Manager
Chicago Zoological Society

2. Sampling Technique
All samples taken with a single-stage Andersen N6 Microbial Impactor at 28.3 L/min flow
Agar: Dichloran Glycerol, 18% Chloramphenicol (DG18) – selective for certain molds and fungi, including Aspergillus (mold), Penicillium (fungus), Candida (yeast), and Saccharomyces (yeast)
Sample time = 3 minutes
Plates incubated at 250 C for 72 hours
Plates counted at 24, 48 and 72 hours
Plates digitally photographed after 72 hours of incubation
Several hundred species of Aspergillus and Penicillium, so initial focus was placed on enumeration rather than identification

3. Andersen N6 Microbial Impactor Kit
Comprised of 4 components
Vacuum pump, hose, impactor (inlet cone, jet stage, base plate), and nutrient agar plate
Air enters through the inlet cone, and velocity is increased as air passes through the jet stage
Small particles avoid plate impact and are filtered from the vacuum pump exhaust
Larger particles (airborne mold and fungal spores) impact the plate and are cultured for enumeration during incubation

4. Andersen N6 Microbial Impactor Kit

5. Andersen N-6 Microbial Impactor
Vacuum Pump

6. Examples of Yeasts and Molds That Will Grow on DG18 Agar
Examples of Aspergillus and Pennicillium
Photo by: Dr. David Midgley Cultures: Dr. David Midgley University of Sydney, Australia.
Example of Candida (yeast)
Thaimedicalnews.com

7. Site 1
Before Renovation
47 spores/m3
After Renovation
0 spores/m3

8. Site 2
Before Renovation
482 spores/m3
After Renovation
0 spores/m3

9. Site 3
Before Renovation
447 spores/m3
After Renovation
0 spores/m3

10. Site 4
Before Renovation
718 spores/m3
After Renovation
0 spores/m3

11. Site 5
Before Renovation
24 spores/m3
After Renovation
0 spores/m3

12. Site 6
Before Renovation
82 spores/m3
After Renovation
0 spores/m3

13. Site 7
Before Renovation
635 spores/m3
After Renovation
12 spores/m3

14. Site 8
Before Renovation
71 spores/m3
After Renovation
12 spores/m3

15. Site 9
Before Renovation
612 spores/m3
After Renovation
0 spores/m3

16. Outside Comparison Before Renovation 94 spores/m3 After Renovation

17. Data Table Exhibit/Area 04/21/08 Before Renovation Spores/m3
09/28/10 After Renovation
Site 1 47
Site 2
482
Site 3
447
Site 4
718
Site 5 24
Site 6 82
Site 7
635 12
Site 8 71
Site 9
612
Outside Comparison 94 35

18. Renovation Details Related to Air Quality
All live plants were removed and replaced with synthetic plants
All soil was removed
Planter boxes were demolished or repurposed
Ductwork into the stadium was sealed from soil
Fans added over north and south holding pools to improve air circulation at the air/water interface
Building HVAC system was upgraded
Stadium was thoroughly cleaned and repainted

19. Before Renovation

20. After Renovation

21. Next Steps
Continue to perform seasonal air quality testing at location and other areas where vets have seen Aspergillosis cases
Proactively seek out and sample exhibits with environmental conditions that favor the growth of Aspergillus (live plants, soil, high humidity, poor air circulation)
Prepare DG18 agar in-house to reduce costs and wait time for prepared plates
Analyze tape samples from plates to learn to identify commonly found molds and fungi

22. Sources
1. Dykstra, M., M. Loomis, K. Reninger, D. Zombeck and T. Faucette (1997). A Comparison of Sampling Methods for Airborne Fungal Spores During an Outbreak of Aspergillosis in the Forest Aviary of the North Carolina Zoological Park. Journal of Zoo and Wildlife Medicine 28 (4),
2. Wilson, S.C., D.C. Strauss (2002). The Presence of Fungi Associated with Sick Building Syndrome in North American Zoological Institutions. Journal of Zoo and Wildlife Medicine 33 (4),
3. J.D. Cooly, W.C. Wong, C.A. Jumper, D.C. Strauss (1998). Correlation Between the Prevalence of Certain Fungi and Sick Building Syndrome. Occupational Environmental Medicine 55,