Modelling the effects of climate change on air quality over Central and Eastern Europe: concept, evaluation and projections

This paper presents regional scale simulations aiming to assess the sensitivity of future air quality under anticipated climate change, with a focus on near-surface ozone (O-3) and particulate matter with a diameter <10 mu m (PM10). Constant anthropogenic emissions and biogenic emissions varying with climate were used. The modelling was carried out with regional climate models coupled to Chemical Transport Models for 3 decadal time slices, under the IPCC A1B scenario, in both coarse (50 km) and high (10 km) resolution for Europe and for targeted domains of Central-Eastern Europe (CEE), respectively. Two modelling systems were applied: the RegCM/CAMx and ALADIN-Climate/CMAQ driven by ECHAM5 and ARPEGE global climate models, respectively. A comprehensive 'operational' evaluation of the performance of modelling systems driven by re-analysis of ECMWF ERA-40 fields was carried out for one full year. Our modelling systems fulfilled the fractional bias (FB) and fractional error (FE) skill criteria and the benchmark of index of agreement (IA) for maximum daily running 8 h mean O-3, with FBs ranging from +4 to -11%, FEs of 14 to 31% and IAs of 0.63 to 0.87. The models' performance for annual, winter and daily mean PM10 was weaker, with FBs of -3 to -49% and FEs of 38 to 66%, but skill criteria for PM were met. Those results justified the use of proposed modelling systems for future time projections. The simulated changes in climate has rather weak impacts on the air quality of the mid-century (2041-2050). For the end-century (2091-2100), our study shows an increase in summer mean O-3 and a decrease in annual mean PM10 in CEE. The main climate factors responsible for projected changes were an increase in summer temperature and a decrease in summer precipitation for O-3, and an increase in winter precipitation for PM10.