The objective of this paper was to assess the air pollution and the main sources of Air Particulate Matter in the Setúbal
urban/industrial area, Portugal. PM2.5 and PM2.5–10 were sampled in Nuclepore filters and lichens transplants were exposed during 9 months. The levels of elements in these two
matrixes were measured by INAA and PIXE. A large data base was created and source apportionment was performed by using Principal
Component Analysis. The results showed that the main sources of fine particles were anthropogenic and were related with traffic
and local industry. There was an important contribution of natural sources, mainly for the coarse fraction, associated with
the sea and the soil. Lichens characterization and mapping showed that different site-specific characteristics controlled
the spatial distribution of different elements. This study showed that biomonitoring is an effective complementary method
to traditional sampling systems.