Model stability The R2values for the leave-one-out cross validations ranged from 0.53 to 0.66 for the NO models, 0.51 to 0.58 for NO2models, and from 0.42 to 0.63 for the NOXmodels (Table 1, and Tables S3–S11,Supplemental information). A final leave-one-out cross-validation (LOOCV) c...