fig2
![Tobacco-specific and combustion pollutants in settled house dust in Malta](https://image.oaes.cc/290ca799-1b19-485e-9c7a-f6b244f5dcd1/4621.fig.2.jpg)
Figure 2. Concentration (in ng/g) of nicotine, nicotelline, ∑TSNA, and ∑PAH in indoor SHD in different districts. District classification (number of samples): 1: urban (10); 2: urban background/rural (7); 3: urban/harbor (14); 4: urban background/rural (7); 5: quarries/industrial/trans-shipment hub (16). ○: Outliers; *: extreme values.