Bioaerosol concentration at an outdoor composting center

Compost centers are one of many environments that produce airborne microorg anisms. The objective of this study was to compare the bacterial, fungal, a nd actinomycete concentrations at the Norman, OK, compost center to backgro und concentration of these same microorganisms. For this comparison, a modi fied Andersen Microbial Sampler was used. Sampling was performed at three s ites at the outdoor compost center and at two background sites. The concent ration of each microorganism was measured as total colony forming units per cubic meter (CFU/m(3)). The predominantly downwind compost center site had a 10-fold increase in all the microorganisms in comparison with the other sites (p < 0.05). The median concentrations (95% confidence interval) of to tal viable bacteria, Gram-negative bacteria, fungi, and actinomycetes at th is site were 5059 (CI95 = 4952-9600) CFU/m(3), 2023 (CI95 = 2586-6806) CFU/ m(3), 972 (CI95 = 964-1943) CFU/m(3), and 2159 (CI95 = 1755-4190) CFU/m(3), respectively.