Determination of selected microbial volatile organic compounds by diffusive sampling and dual-column capillary GC-FID - a new feasible approach for the detection of an exposure to indoor mould fungi?

A new, analytically valid procedure is described to assess the exposure of human beings to the so-called microbial volatile organic compounds (MVOCs) in air. The method can be used routinely for large sample numbers and is es pecially valuable as a basis for further research on the correlation betwee n single MVOCs and indoor mould growth. The procedure is based on the fact that fungi produce a variety of volatile organic compounds, such as 3-methy lbutan-1-ol, 3-methylbutan-2-ol, fenchone, heptan-2-one, hexan-2-one, octan -3-one, octan-3-ol, pentan-2-ol, alpha-terpineol, and thujopsene, which the y emit into the indoor environment. Using diffusive samplers, these MVOCs a re adsorbed onto charcoal during a sampling interval of four weeks. The des cribed method is thus superior to existing methods which use short-term act ive sampling. After desorption with carbon disulfide, the MVOCs were determ ined by dual-column gas chromatography with flame ionization detection usin g the large-volume injection technique for sample introduction. The detecti on limits ranged between 0.15 and 0.53 mu g m(-3) within-series precision w as found to range between 6.5 and 19.0%, and recovery was between 77 and 11 8%. The procedure has been sucessfully applied in the context of a large fi eld study to measure the indoor MVOC exposure in children's rooms of 132 dw ellings. The objective of the study was to examine the relation between ind oor mould growth, the indoor MVOC exposure and the prevalence of adverse he alth effects. Information about mould formation has been obtained by a ques tionnaire and by the determination of colony forming units of mould fungi i n mattress dust. With the exception of 3-methylbutan-2-ol, fenchone, nonan- 2-one, octan-2-one, and thujopsene, indoor air concentrations of all MVOCs under investigation were significantly higher inside damp and mouldy dwelli ngs. From the primary MVOCs under investigation, 3-methylbutan-1-ol, hexan- 2-one, heptan-2-one, and octan-3-ol were found to be most reliable indicato rs for mould formation. A correlation was also found between selected MVOCs and the occurance of mould species in mattress dust. Aspergillus sp. corre lated with heptan-2-one, hexan-2-one, octan-3-ol octan-3-one, and cr-terpin eol, while the occurrance of Eurotium sp. was correlated with higher indoor air concentrations of 3-methylbutan-1-ol, 3-methylbutan-2-ol, heptan-2-one , hexan-2-one, octan-3-ol, and thujopsene. Children living in dwellings wit h elevated MVOC levels had a higher prevalence of asthma, hay fever, wheezi ng, and irritations of the eyes. These positive associations persisted afte r controlling for confounding factors such as age, sex, body-mass index, nu mber of siblings, social status, passive smoking, type of heating, and vent ilation habits. However, they were not statistically significant. This lack of significance may be a result of the small number of investigated sample s.