Airborne Endotoxin and ß-D-glucan in PM1 in Agricultural and Home Environments

Received: March 1, 2011
Revised: May 20, 2011
Accepted: May 20, 2011
Download Citation: RIS|BibTeX|https://doi.org/10.4209/aaqr.2011.03.0019  

Cite this article:
Singh, U., Reponen, T., Cho, K.J., Grinshpun, S.A., Adhikari, A., Levin, L., Indugula, R. and Green, B.J. (2011). Airborne Endotoxin and β-D-glucan in PM1 in Agricultural and Home Environments. Aerosol Air Qual. Res. 11: 376-386. https://doi.org/10.4209/aaqr.2011.03.0019

ABSTRACT

Objectives: Concentrations of microbial cell wall components such as endotoxin and β-D-glucan in airborne submicrometer particle size fraction (PM₁, defined as particles with median aerodynamic diameter, da ≤ 1 μm) have not been well characterized. In this study, airborne concentrations of endotoxin and β-D-glucan among different size fractions were quantified in two distinctly different environments: farms and homes. Effect of microbial source (farm type for farms and mold damage for homes) on size-fractionated concentrations was investigated.

Methods: Airborne endotoxin and β-D-glucan were collected on 7 farms and 184 suburban homes using NIOSH two-stage sampler, a cyclone air sampler that fractionates airborne particles into three size fractions: ≤ 1 μm, 1–1.8 μm and ≥ 1.8 μm.

Results: Geometric means (geometric standard deviations) of airborne total endotoxin concentration on farms and in homes were 1.20 × 10⁴ (7.57) EU/m³ and 2.67 (3.82) EU/m³, respectively. Similar values of airborne total β-D-glucan concentrations were 1.80 × 10³ (152.88) ng/m³ and 1.91 (2.83) ng/m³, respectively. Relative proportions of PM₁ endotoxin, however, were significantly higher (p < 0.001) in home samples (7.9%) than in farm samples (0.3%). Likewise, the proportion of PM₁ β-D-glucan was significantly higher (p < 0.001) in homes (28.2% vs. 2.3%). Farm type significantly influenced concentrations of PM₁ β-D-glucan (p < 0.05) and total β-D-glucan (p < 0.001).

Conclusions: The results of this study demonstrate higher proportions of PM₁ endotoxin and β-D-glucan in homes compared to farms. These data further emphasize the importance of conducting size-selective air sampling for microbial exposure assessment in homes.

Keywords: Bioaerosol; Fine particles; Farms; Moldy buildings; Size-Selective sampling