An Incinerator Air Quality Impact Assessment for Metals, Pah, Dioxins and Furans by Using Mm5-cmaq: Spain Case Study

The increased interest to carry out air quality impact assessment by using sophisticated and state-of-the art air quality modeling systems has conducted us to simulate the air quality impact of a projected incinerator in the Basque Country (North of Spain) area (San Sebastian) as requested by the promoter. In this contribution we show the implementation of a modified version of MM5-CMAQ [3] for carrying on the incinerator air quality impact. The modified CMAQ model (EPA USA, 2004) includes Poly-Chlorinated Dibenzo-p-Dioxins and Dibenzo-Furans (dioxins and furans). The model represents their cogeners as divided between gaseous and aerosol forms that exchange mass based on theoretical coefficients for gas to particle portioning. Modelled metals are included in CMAQ as part of the non-reactive aerosol component. Metals modelled are: As, Cd, Ni and Pb. In additional Benzo(a)pyrene (PAH) is also modelled. The study uses the socalled ON/OFF approach which assumes that the differences between the simulation ON – full emissions including maxima expected incinerator emissions – and OFF – exactly the same emissions than ON but without the emissions coming from the projected incinerator -. The emissions of the projected incinerator in the ON run are incorporated by using the height of the chimney, the prescribed exit gas velocity, diameter of chimney and the limit emission values (worst scenario) prescribed in the Directive/2000/76/CE. The OFF run is done by using EMEP POP and PAH emission inventory. The system is mounted over one mother domain of 400 x 400 km with 9 km spatial resolution and two nesting levels: 99 km model domain with 3 km spatial resolution and 45 km with 1 km spatial resolution. All model domains with 23 vertical layers up to 100 mb and centered over the UTM coordinates prescribed for the projected incinerator. EPER EU industrial emissions (May, 2004) of the surrounding large point industrial sources are used. Results are compared with the target values included in the proposal for a Directive of the European Parlament and of the Council (ENV 194 CODEC 439). The study includes the relative impact of six large industrial plants currently operating in the area and the relative impact of the A8 highway over the 45 x 45 km model domain (1 km spatial resolution). Results offer an excellent detailed set of results by establishing a comparison between the different industrial plants currently operationg, highway and projected incinerator.