Figure 2.

Computation of the AUROC confirmed favorable discriminatory power of NDPM₁₀ (AUROC =0.564±0.024; 95% CI, 0.51–0.61; P=0.007).

Notes: The optimal cutoff point for NDPM₁₀, derived from the maximal value of the Youden index, was 4.5 days/12 months (sensitivity, 48%; specificity, 74%). Green line represents reference line. Blue line represents NDPM₁₀.

Abbreviations: AUROC, area under the receiver operating characteristic; CI, confidence interval; NDPM₁₀, the number of days of mean 24-hour PM₁₀ ≥125 μg/m³/12 months; PM₁₀, particulate matter with a diameter of <10 μm.