Figure 2.

Ambient Temperature & Relative Humidity and COVID-19 Transmission

Associations of ambient temperature (A, province level; B, city level) and relative humidity (C, province level; D, city level) with the transmission rate of COVID-19. Transmission rate was defined as the increased rate of cumulated confirmed cases per day in a logistic growth model: Equation (1). The regression coefficients (β₁ and β₂) were obtained using a linear mixed-effect model as follows: R_{[t, s]}= β₁T_t+ β₂RH_t+ β₃WS_t + β₄PR_t+ β₅MII_t+ β₆MOI_t+ β₇PD_t + γ(L). This formula incorporated seven fixed terms (β_1-7) to model the effects of temperature (T), relative humility (RH), wind speed (WS), precipitation (PR), population mobility indexes of moving-in (MII) and moving-out (MOI), population density (PD), and a random intercept (γ) to control for the location (L)-specific effects. Data are shown with an estimated value with 95% confidence interval.