Table 7: Comparison of Al2O3 concentrations in the air at workstations in the exposed group between subjects without and with symptoms.

Respiratory chronic symptoms Al2O3 concentrations (mg/m3) in the exposed group (Mean ± SD) p-Value*
Without symptoms With symptoms
Asthma 1.12 ± 0.81 1.80 ± 0.90 0.006**
Chronic cough 0.99 ± 0.78 1.77 ± 0.82 0.001***
Morning cough with sputum 1.14 ± 0.83 1.64 ± 0.91 0.033*
Phlegm 1.27 ± 0.85 1.35 ± 1.47 0.882
Chronic phlegm 1.32 ± 0.88 0.82 ± 0.80 0.220
Wheeze 1.21 ± 0.85 1.84 ± 0.86 0.054
Respiratory problems (asthma, coughing) caused by current work 1.15 ± 0.79 2.43 ± 0.76 0.001***

T-test: *significant at P < 0.05, **significant at P < 0.01, ***significant at P < 0.001.