Relationship between different bioaerosol parameters sampled from the breathing zone of waste collectors - identification of the most important parameters*
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Rendan A/S, Søborg, Denmark
National Institute of Occupational Health, Copenhagen, Denmark
Ann Agric Environ Med. 1997;4(1):81–85
Measurements of the exposure to bioaerosols are often necessary in studies on the causality of occupational respiratory problems, but controversy exists on the relevance of different bioaerosol exposure parameters as well as on the proper methods for sampling of bioaerosol and analysis of the parameters. The aim of the present study was to elucidate possible correlations between different general microbiological parameters obtained from personal sampling of bioaerosols on filters, and to identify the parameters most useful in the discrimination between exposure levels of waste collectors. Bioaerosol sampling was carried out with the assistance of Danish waste collectors (n = 199) collecting household waste. For a full work shift each waste collector carried two field monitors (25 mm) with filters for the collection of aerosols. The following general exposure parameters were measured: total dust; endotoxin; total counts of microorganisms by epifluorescence microscopy including differential counts of fungal spores, spherical and rod shaped bacteria; culturable bacteria and fungi on agar plates (viable counts). The relationships between the different parameters were investigated by parametric correlation analysis (Pearsons) after logarithmic transformation of the data. Principal component analysis was used to study the contribution of the parameters with respect to the variance between independentsamples of bioaerosols. A statistically significant positive correlation (p < 0.05) was observed between a number of different parameters. However, the correlation coefficients were in all cases low (0.2 < r < 0.7). Consequently, the prediction of a bioaerosol parameter based on data of other parameters is expected to have a limited accuracy and validity. Principal component analysis revealed that total counts of fungal spores and rod shaped bacteria can account for 93% of the variance between independent bioaerosol samples. The result is unlikely to be due to poor analytical performance of the method. It is concluded that the total count parameter may provide the best exposure stratification of waste collectors in epidemiological studies and in routine monitoring of workplace exposure.