Fig 13. Examples of 12-hour gap filling in PM2.5 time series (μg/m3) by representative models with varying performance: (a) XGB Seq2Seq, (b) RF Seq2Seq, (c) UniSeq2Seq XGB, (d) XGB Autoreg, (e) Local Imputation Mean, and (f) Simple Imputer Mean.
The blue line shows actual values, while the red line indicates predicted values within the gap.
