Collection Efficiency and Culturability of Impingement into a Liquid for Bioaerosols of Fungal Spores and Yeast Cells
Titel:
Collection Efficiency and Culturability of Impingement into a Liquid for Bioaerosols of Fungal Spores and Yeast Cells
Auteur:
Lin, Wen-Hai
Verschenen in:
Aerosol science and technology
Paginering:
Jaargang 30 (1999) nr. 2 pagina's 109-118
Jaar:
1999-02-01
Inhoud:
Collection efficiency of AGI-30 impingers and culturability of collected fungal bioaerosols were evaluated in a laboratory test system. A Pitt-3 generator and a Collison nebulizer aerosolized spores of Penicillium citrinum (P. citrinum) and yeast cells of Candida famata (C. famata) var. flareri , respectively. A 37-mm 3-piece cassette containing a 0.4- mu m Nuclepore filter was adapted to the outlet of the test impinger to collect the particles penetrating the sampler. The particles deposited on the inlet tube were also extracted to evaluate the wall loss effect. The physical collection efficiency was evaluated by counting the fungal particles of three portions of the impinger (inlet tube, AGI-30, and outlet) using a haemocytometer. In addition, the culturability was determined as the ratio of CFU concentration to total concentration measured by the haemocytometer. Our results demonstrated that the impinger could collect more than 90% of the particles, and less than 1% of the particles were found in the inlet tube. Moreover, physical collection efficiency became higher as sampling flow rate increased, but became lower as the sampling time increased for collecting P. citrinum spores. For yeast cells, the collection efficiency was nearly 100% and was similar for both sampling duration and flow rates. In addition, culturability of spores collected by the impinger was in the range of 4.5-34% and decreased as sampling time and flow rate increased. However, it was demonstrated that yeast culturability was in the range of 70-85% and did not depend on sampling time and flow rate. Moreover, the culturability of both strains in generators was found to be close to 100% during the test. Therefore, it was noted that the P. citrinum spores were more sensitive to impingement stress than yeast cells. In addition, hydrophobicity and contact effect might also contribute to the observed low recovery of the spore samples.
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