(1 → 3)-β-D-glucan in different background environments and seasons

This study was undertaken to investigate how the length of the extraction period influences the (1 -> 3)-beta-d-glucan (beta-glucan) yield and also to examine the background concentration of beta-glucan as airborne beta-glucan in outdoor environments in different seasons and as concentrations in airborne and floor dust in offices. To ensure compatibility between results obtained in different laboratories, it is important to use optimal and standardised methods to extract and quantify beta-glucan. In this study, an extraction period of 60 min gave the highest beta-glucan yield. The median concentration of beta-glucan in 44 floor dust samples was 597 mu g g(-1) dust. The median concentration of airborne beta-glucan in offices was 5.1 ng m(-3) in the summer and 2.3 ng m(-3) in the winter, and the outdoor median concentration in towns was 6.8 ng m(-3). The outdoor airborne concentration of beta-glucan was significantly lower in January, November and December than during the rest of year. In July, the median airborne concentration of beta-glucan was 14 times higher than in January. Furthermore, the airborne concentration of beta-glucan was significantly higher in July than in March, April, May, September and October. In the summertime, we found that the indoor airborne concentration of beta-glucan was lower than outdoor concentrations. This is in accordance with measurements of concentrations of airborne pollen and culturable fungal spores showing higher outdoor than indoor concentrations during the summer months.