Comparison of shape of particulate matter in the study population according to use of personal protective precautions
| Exposed workers (n=29) | Nonexposed controls (n=40) | Protection* | |||
| Yes (n=13) | No (n=16) | p-value | |||
| Grey level | 85.0±1.0 | 114.8±29.9 | 85.3±1.0 | 84.8±1.0 | 0.254 |
| Average Ferret diameter μm | 3.6±0.7 | 4.4±1.7 | 3.15±0.32 | 3.90±0.84 | 0.014 |
| Circularity | 0.46±0.02 | 0.53±0.1 | 0.47±0.02 | 0.45±0.01 | 0.084 |
| Convexity | 0.85±0.009 | 0.87±0.03 | 0.853±0.01 | 0.847±0.008 | 0.066 |
| Concavity | 0.84±0.006 | 0.86±0.03 | 0.841±0.006 | 0.836±0.005 | 0.031 |
Data are presented as mean±sd unless otherwise stated. Protective measures applied in the workshop and personal protective equipment are described in the Methods section. Sizes measured by image analysis as described in the Methods section. The use of protection means was evaluated by the questionnaire. *: p<0.05 (t-test) for dust exposure and Kruskal-Wallis for protection method.