Field Evaluation of a Personal, Bioaerosol Cyclone Sampler

Abstract

A personal cyclone sampler (cyclone) was operated continuously alongside a 25-mm filter sampler (filter), a slit impactor (Burkard slide), and a high-volume cyclone sampler (Burkard cyclone) at an outdoor location with abundant naturally occurring fungi (N = 30; sampling time: 12.5 ± 2.3 hr). Air concentrations (spore m^-3) of 28 fungal groups were determined for all samplers by microscopy. Cyclone performance was judged using various indices to determine if it agreed with the other samplers in determination of the frequencies with which the fungal groups were observed, as well as their proportions of the total air concentration. Fungal diversity estimates were similar for all samplers and in the range of what has been reported nationally, i.e., observation of 9–11 equal groups per sample, but spore concentration dominated by 2–3 groups. Plots of paired cyclone:comparison sampler ratios against average concentrations identified biases. For example, ratios were correlated with concentration and there was greater uncertainty at lower concentrations. Mean ratios for cyclone:filter comparisons were not significantly different from one for ascospores, Aspergillus-Penicillium spp., basidiospores, Cladosporium spp., or total spore m^-3. However, agreement was less consistent with the Burkard slide (0.74, 1.12, 0.91, 1.09, and 0.92, respectively) and the Burkard cyclone (2.31, 1.62, 1.43, 1.91, and 1.33, respectively). Concentrations of cell equivalent m^-3 also were determined for the filter and two cyclone samples by polymerase chain reaction. Cell equivalents for Aspergillus fumigatus and Penicillium brevicompactum were compared with Aspergillus-Penicillium spp. spores, and Cladosporium cladosporioides and Cladosporium herbarum cell equivalents were compared with Cladosporium spp. spores. Cell equivalent:spore ratios below one for A. fumigatus and P. brevicompactum indicated that these species comprised smaller factions of total spores or were collected less efficiently than the larger C. cladosporioides and C. herbarum spores. The personal cyclone was shown to be suitable for collection of ambient airborne fungal spores and for analysis by microscopy and polymerase chain reaction.

Keywords:

• cyclone sampler
• fungal biodiversity
• method comparison
• outdoor air
• sampler performance

ACKNOWLEDGMENTS

This work was supported in part by NIOSH contract HELD/EAB Can # 4927007U. “Evaluation and Validation of a Novel Bioaerosol Personal Sampler Project.” The authors thank Robert Miller, Environmental Health Laboratory Branch, California Department of Public Health for help with sample collection; S. Katherine Hammond, Environmental Health Sciences, University of California at Berkeley for loan of the Burkard slide impactors; and John Shane, Pro-Lab, for advice on the Burkard C90 sampler.

The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the National Institute for Occupational Safety and Health.

Notes

^A Refs. 7,14.

^B All fungi were identified for microscopy (spore) and culture (CFU), but only A. fumigatus, C. cladosporioides, C. herbarum, and P. brevicompactum were measured by PCR (CE).