GSTM1 and anemia: In a cross-sectional study of elderly individuals in China, each interquartile range increase in PM10 and PM2.5 concentrations corresponded to a 5% (95% CI = 2–9) and 11% (95% CI = 6–16) increase in anaemia prevalence, respectively, while, for each IQR increment in PM1 and NO2, Hb concentrations decreased by 0.55 (95% CI = 0.41, 0.69) and 1.71 (95% CI = 1.57, 1.85) mg/dL [8].