Correction to: Environmental Science and Pollution Research

https://doi.org/10.1007/s11356-021-13432-5

The correct images of Figs. 3 and 5 are presented in this paper.

Fig. 3
figure 1

The random tree for classifying the ethanol and gasoline blend's environmental impact using the variables ethanol blend and engine rotation

Fig. 5
figure 2

The random tree for classifying the ethanol and gasoline mixture's environmental impact using λ, ethanol blend, engine rotation, and the air-fuel ratio

The original article has been corrected.