Future air quality in Europe: a multi-model assessment of projected exposure to ozone

Abstract

Abstract. In order to explore future air quality in Europe at the 2030 horizon, two emission scenarios developed in the framework of the Global Energy Assessment including varying assumptions on climate and energy access policies are investigated with an ensemble of six regional and global atmospheric chemistry transport models.A specific focus is given in the paper to the assessment of uncertainties and robustness of the projected changes in air quality. The present work relies on an ensemble of chemistry transport models giving insight into the model spread. Both regional and global scale models were involved, so that the ensemble benefits from medium-resolution approaches as well as global models that capture long-range transport. For each scenario a whole decade is modelled in order to gain statistical confidence in the results. A statistical downscaling approach is used to correct the distribution of the modelled projection. Last, the modelling experiment is related to a hind-cast study published earlier, where the performances of all participating models were extensively documented.The analysis is presented in an exposure-based framework in order to discuss policy relevant changes. According to the emission projections, ozone precursors such as NO x will drop down to 30 % to 50 % of their current levels, depending on the scenario. As a result, annual mean O 3 will slightly increase in NO x saturated areas but the overall O 3 burden will decrease substantially. Exposure to detrimental O 3 levels for health (SOMO35) will be reduced down to 45 % to 70 % of their current levels. And the fraction of stations where present-day exceedences of daily maximum O 3 is higher than 120 µg m −3 more than 25 days per year will drop from 43 % down to 2 to 8 %.We conclude that air pollution mitigation measures (present in both scenarios) are the main factors leading to the improvement, but an additional cobenefit of at least 40 % Published by Copernicus Publications on behalf of the European Geosciences Union.

Tropospheric ozone and its precursors from the urban to the global scale from air quality to short-lived climate forcer

“…At the continental scale the efficiency of emission reductions was demonstrated but models provided a large spread of responses in city centres. The ability of an ensemble of six chemistry transport models to capture recent observed ozone trends was also discussed by Colette et al (2012). They found that models efficiently captured the increase in NO x -saturated areas, such as the Benelux region and the decrease in NO x -limited areas (many rural regions in Europe).…”

“…but an additional co-benefit of at least 40 % (depending on the indicator) was attributed to the climate policy (Colette et al, 2012). A study by Crawford-Brown et al (2012) focused on the co-benefits to O 3 -and PM-related health effects resulting from implementation of climate policy in Mexico.…”

“…In a model ensemble study by Colette et al (2012), future (2030) air quality in Europe owing to just air quality policy or air quality and climate policy was compared. The base case included all current and planned air quality measures up to 2030 and was compared to a "sustainable" case with the air quality as well as climate measures (2 • C target and energy efficiency improvements).…”

Model calculations of the effects of present and future emissions of air pollutants from shipping in the Baltic Sea and the North Sea

“…For ozone the lateral boundary concentrations are based on ozone climatology scaled by measurements from the clean sector at Mace Head, Ireland, unaffected by European emissions. A detailed description of the model can be found in Simpson et al (2012) Colette et al, 2011Colette et al, , 2012Angelbratt et al, 2011).…”

“…With the exception of ship emissions in the Baltic Sea and the North Sea the emissions of air pollutants are based on the EC4MACS Interim Assessment of "Greenhouse gases and air pollutants in the European Union: baseline projections up to 2030" (Amann et al, 2012). The emissions include both land-based emissions and emissions from international shipping.…”