Thermal and epithermal neutron activation analysis techniques were used to analyze 27 Teflon air filters which were exposed
to ambient air in Lisbon, Portugal, in February 2007. Tin was detected which is strongly suggestive of an anthropogenic source.
Arsenic, antimony and copper were shown to be highly correlated, which is also suggestive of anthropogenic pollution. Trace
element analysis of short- and medium-lived isotopes was performed yielding concentration information of various elements.
Analytical sensitivities were enhanced using a Compton suppression system. Enrichment factor analysis shows that arsenic,
tin, zinc, copper and antimony are at elevated concentrations in the Lisbon atmosphere.