Fig. 2
From: Impact of outdoor air pollution on the incidence of pertussis in China: a time-series study
Contour plots of exposure-response relationships between pertussis incidence and four air pollutants in the single-pollutant model. A-D Four air pollutants associated with (PM2.5, SO2, NO2 and O3) pertussis incidence from 2013 to 2018. The reference level was set to the median value of the corresponding variable. The Y-axis represents the lag period from 0 to 2 months. The e-axis represents the range of observations for each variable. RR stands for relative risk, red stands for RR>1, white stands for RR=1, and blue stands for RR<1