Fig. 6

Positive correlations between 8 h TWA CO, Cu, and LDSA. A Correlation between 8 h TWA CO and LDSA, R² = 0.836, p < 0.0001. B Correlation between 8 h TWA CO and Cu, R² = 0.834, p < 0.0001. C Correlation between 8 h TWA Cu and LDSA, R² = 0.989, p < 0.0001