Fig. 5. Contour plots of the exposure–response relationship for the association between scarlet fever incidence and air pollutants or meteorological conditions in the single-variable model.

a–d Four air pollutants from 2013 to 2018. e–i Five meteorological variables from 2004 to 2018. The reference level is set as the median value of the corresponding variable. In the single-variable model, we further adjust the temporal trend, as well as quantile groups both for average incidences and for incidence in the previous month. The Y-axis is the lag month ranging from 0 to 15. The X-axis is the range of the observed values of each variable. The color gradient represents the relative risk (RR). The red color gradient represents higher strength of RR, above 1, and the blue gradient represents lower strength of RR, below 1. The white color represents no difference, at RR = 1. Source data are provided as a Source Data file.