Modeling air concentrations and risk of carcinogens and co–carcinogens in Gibraltar and source apportionment of nearby industrial facilities

Airborne exposures of carcinogenic and co–carcinogenic pollutants, emitted from industries and various diffuse sources in a 10km radius of Gibraltar, were calculated at the west side of the Rock of Gibraltar facing the Bay. 2005 and 2008 industrial annual emission rates reported to E–PRTR and 2005 municipal diffuse annual emission rates were entered in OML–Multi, a multi–source version of an atmospheric Gaussian plume local scale dispersion model. The model results reveal that carcinogens PAH, represented by benzo[a]pyrene (BaP), arsenic and nickel, and potentially chromium are the priority pollutants with respect to human cancer risk and that the contribution from industrial sources on the Spanish coastal area exceeds that from the diffuse sources from adjacent Spanish municipalities. There is a decrease in annual mean air concentrations from industrial emissions between the years 2005 and 2008. The assessment of contribution to the Gibraltar air concentrations of the priority pollutants from industrial sources shows that refinery CEPSA, chemical industry Petresa and petroleum industry Lubricantes del Sur are significant for nickel. Chemical industry Interquisa is significant for PAHs with a notable decrease in PAH emissions from 2006 to 2007, whereas the contribution from CEPSA is more constant. For arsenic only CEPSA shows a continuous trend and contributes to the 2008 air concentration together with sewerage Edar de la Linea de la Concepcion. CEPSA and metal industry Acerinox contribute the most to the chromium air concentrations. NO2/NOx is the most critical co–carcinogen and electricity plant Central Termica Los Barrios, CEPSA, electricity plant Generacion Electrica Peninsular and electricity plant Cogeneracion de Interquisa are the most significant contributors to the air concentrations in Gibraltar. Pollutant contributions from CEPSA flaring, ship traffic in the Bay and Strait, local road traffic and local diesel generators are currently un–quantified.