Fig. 2
Odds ratios for the asthma worsening episodes per interquartile range (IQR) increase in concentrations of PM2.5 total mass and five chemical species in Nagasaki city (A and B) and Isahaya city (C and D), estimated by the generalized linear mixed effects model adjusting for potential confounders and PM2.5 mass. The episode was defined if the percent reduction in daily peak expiratory flow (PEF) from the personal best monthly PEF was > 15% within a rolling 1-week window. Different lag days were applied to the morning PEFs (A and C) on the preceding day (lag1), the cumulative exposure during two preceding days (clag1–2), and the cumulative exposure during three preceding days (clag1–3) and the evening PEF (B and D) on the current day (lag0), the cumulative exposure on the current day and the preceding day (clag0–1), and the cumulative exposure up to two preceding days (clag0–2). The vertical bars indicate the 95% confidence intervals. OC: organic carbon; EC: elemental carbon