Non–specific respiratory irritation is also observed, particularly
at higher concentrations of dust as it can result in non–allergic
rhinitis, conjunctivitis and bronchitis. In some studies 40–50% of
the employees were affected with these diseases. Table 1
illustrates the summary of statistical anthropometric measure‐
ments of the cases and controls. The average of age, weight and
height of workers (cases) were compatible with the control
subjects in the current study