Diffusive sampling has been used to study the spatial distribution of SO(2), NO(2), NO(x), NH(3) and BTX (benzene, toluene and xylenes) near an oil refinery located in Falconara, Italy, over the period from March to October 2001. Three different categories of sampling sites (roadside, residential and background) were studied. In total, 56 sites were monitored. The results were evaluated on the basis of the limit values found in the European Directives. The results of the defined study indicate that the measured concentrations were substantially lower than the ambient air quality standard with the maximum concentrations being generally found much closer to emission sources. The monitoring method described here can be used to assess integrated concentration levels over long periods of time and to identify pollution "hotspots" where concentrations are likely to be consistently high. Identification of these hotspots may help to assess air quality and to implement proper action plans, especially in locations where industrial and urban pollution coexist.