Using WRF-CMAQ Air Quality Modelling System to Estimate BaP Concentrations over Zaragoza (Spain)

Abstract

The main aim is to estimate the BaP concentrations in the atmosphere and know the main influences on BaP ground level concentrations. We have utilized CMAQ 4.7 version as core for our system. BaP degradation and adsorption mechanism have been integrated into the chemical-transport model. Emissions have been processed the EMIMO-UPM emission model with a top-down approach including detailed GIS data. The air quality model has been driven by the WRF meteorological model. Urban particulate material generally contains a significant amount of amorphous organic carbon. Absorptive mechanism plays the dominant role in the urban air and also in air affected by urban sources. Equilibrium partitioning calculations are based on absorptive partitioning model. Gas/particle partitioning of BaP is simulated as an absorption process into the organic mass on the aerosol particle assuming the formation of a quasi-ideal solution. BaP reaction with ozone is an important degradation pathway of the particulate BaP in the atmosphere. The degradation rate constant depends on the ozone gas to surface equilibrium constant and the maximum rate coefficient that would be observed at high ozone concentrations. A validation process of the BaP and other pollutant results has been conducted in the urban area of Zaragoza (Spain) during 10 weeks in 2010. The agreement is generally satisfactory. The simulated concentrations depend on the meteorological and emission inputs.