Cotton dust and endotoxin levels in three Shanghai textile factories: a comparison of samplers

The results of a field survey at three Shanghai textile factories were used to compare the performance of the Chinese dust sampler (CDS) with the standard American sampler, vertical elutriator (VE). Side-by-side samples using a CDS and a VE were collected in seven specific manufacturing processes, with additional area and personal samples collected with a modified Institute of Occupational Medicine (IOM) personal inhalable sampler. Filters were analyzed for mass and endotoxin concentration. The geometric mean (GM) of the samples collected by the CDS was 0.79 mg/m3 (geometric standard deviation [GSD] 1.9) compared with a GM of 0.31 mg/m3 (GSD 1.7) for the VE measurements. The correlation coefficient for the CDS and VE samples was 0.35. The CDS, a high-volume total dust area sampler, collects 2 to 10 times more dust than the VE, a size-selective method, depending on the manufacturing process. In spinning at Factory A, the VE and CDS measured concentrations of 0.15 mg/m3 and 1.62 mg/m3, respectively. Cotton dust concentration measurements collected by the IOM sampler demonstrated that personal exposure concentrations were significantly higher (GM 1.84 mg/m3, GSD 1.6) than fixed-position area samples (GM 0.68 mg/m3, GSD 1.9). The endotoxin concentration based on the VE samples was 366 EU/m3, with the highest levels found in the specific manufacturing process drawing (1871 EU/m3) and the lowest in spinning (43.5 EU/m3). The results of the field comparison were used to convert historic CDS data into comparable exposures and to assign retrospective exposures to subjects included in a case-cohort study of lung cancer among female textile workers in Shanghai.