Fig. 3From: Association between elevated serum bilirubin levels with preserved lung function under conditions of exposure to air pollutiona Assessment of FEV1 according to different levels of serum bilirubin under different NOx levels. FEV1 forced expiratory volume in 1 s, Nox nitrogen oxide. Y axis—mean level of FEV1 percent of predictive values. X axis—NOx level (low, medium and high; 0.4–14.0 ppm; 14.1–22.1 ppm and 22.2–33.5 ppm, respectively). Bilirubin level (mg/dL) divided according to low, moderate, and high serum bilirubin; 0.1–0.59 mg/dL, 0.6–0.8 mg/dL and 0.81–1.47 mg/dL, respectively. b Assessment of FEV1 according to different levels of serum bilirubin under different CO levels. FEV1 forced expiratory volume in 1 s, CO carbon monoxide. Y axis—mean level of FEV1 percent of predictive values. X axis—CO level (low 0.1–0.7 ppm; medium and high 8–0.9 ppm and 1–1.2 ppm). Bilirubin level (mg/dL) divided according to low, moderate, and high serum bilirubin; 0.1–0.59 mg/dL, 0.6–0.8 mg/dL and 0.81–1.47 mg/dL, respectivelyBack to article page