Partial correlation analysis between Mn-CEI and pulmonary function values of workers.

<p>r₁, the partial correlation coefficients of smoking male workers in the high exposure group</p><p>r₂, the partial correlation coefficients of non-smoking male workers in the high exposure group</p><p>r₃, the partial correlation coefficients of female workers</p><p>Partial correlation analysis between Mn-CEI and pulmonary function values of workers.