P. Huszar

On the long-term impact of emissions from central European cities on regional air quality

For the purpose of qualifying and quantifying the impact of urban emission from Central European cities on the present-day regional air-quality, the regional climate model RegCM4.2 was coupled with the chemistry transport model CAMx, including two-way interactions. A series of simula5 tions was carried out for the 2001–2010 period either with all urban emissions included (base case) or without considering urban emissions. Further, the sensitivity of ozone production to urban emissions was examined by performing reduction experiments with −20 % emission perturbation of NOx 10 and/or non-methane volatile organic compounds (NMVOC). The modeling system’s air-quality related outputs were evaluated using AirBase and EMEP surface measurements showed reasonable reproduction of the monthly variation for ozone (O3), but the annual cycle of nitrogen dioxide (NO2) 15 and sulfur dioxide (SO2) is more biased. In terms of hourly correlations, values achieved for ozone and NO2 are 0.5–0.8 and 0.4–0.6, but SO2 is poorly or not correlated at all with measurements (r around 0.2–0.5). The modeled fine particulates (PM2.5) are usually underestimated, especially in win20 ter, mainly due to underestimation of nitrates and carbonaceous aerosols. European air-quality measures were chosen as metrics describing the cities emission impact on regional air pollution. Due to urban emissions, significant ozone titration oc25 curs over cities while over rural areas remote from cities, ozone production is modeled, mainly in terms of number of exceedances and accumulated exceedances over the threshold of 40 ppbv. Urban NOx, SO2 and PM2.5 emissions also significantly contribute to concentrations in the cities them30 selves (up to 50–70 % for NOx and SO2, and up to 60 % for PM2.5), but the contribution is large over rural areas as well (10–20 %). Although air pollution over cities is largely determined by the local urban emissions, considerable (often a few tens of %) fraction of the concentration is attributable 35 to other sources from rural areas and minor cities. For the case of Prague (Czech Republic capital), it is further shown that the inter-urban interference between large cities does not play an important role which means that the impact on a chosen city of emissions from all other large cities is very small. 40 At last, is shown that to achieve significant ozone reduction over cities in central Europe, the emission control strategies have to focus on the reduction of NMVOC, as reducing NOx (due to suppressed titration) leads often to increased O3. The influence over rural areas is however always in favor of im45 proved air-quality, i.e. both NOx and/or NMVOC reduction ends up in decreased ozone pollution, mainly in terms of exceedances.

Forecasting Models for Urban Warming in Climate Change

Defining UHI phenomenon required and interdisciplinar approach using both simulation models and climate data elaborations at regional and metropolitan level. In particular the WP 3 of UHI project provided a detailed survey on the main studies and practices to counteract urban heat islands in different European areas; discussed climate models at regional level; simulated the evaluation of urban warming in the different cities involved in the project, providing locally proper measuring and analysis in connection with the specific urban forms.

Urban Impact on Air Quality in RegCM/CAMx Couple for MEGAPOLI Climate Change Study in High Resolution

For the purpose of qualifying and quantifying the climate forcing due to atmospheric chemistry/aerosols on regional scale, the regional climate model RegCM3 has been coupled with the chemistry/aerosol model CAMx. Experiments with the couple have been run for EC FP7 project MEGAPOLI assessing the impact of the megacities and industrialized areas on climate. New domain have been settled in 10 km resolution including all the European “megacities” regions, i.e. London metropolitan area, Paris region, industrialized Ruhr area, Po valley etc. TNO emissions are adopted to resolve urban areas. A sensitivity test of the resolution effect is presented to reveal whether the concept of effective emission indices could help to parameterize the urban plume effects in lower resolution models. The sensitivity test to switch on/off Paris area emissions is analysed as well.

Pilot Actions in European Cities – Prague

This chapter describes results of pilot actions in Prague. Two different pilot areas were selected (Legerova street and Bubny-Holesovice quarter) with different modelling approach. Finally, the Green belt around Prague is studied as well. Different scenarios are tested and their results discussed. The matter of air quality is also analysed.

Verification of Ship Plumes Modelling and Their Impacts on Air Quality and Climate Change in QUANTIFY EC 6FP Project

The impact of emission from transportation on climate change is being quantified in EC FP6 Integrated Project QUANTIFY. In Activity 2 the analysis of the dilution and transformation of the emission from microscale at exhausts and plumes till mesoscale distribution will be provided from all modes of transportation. In this contribution the mesoscale simulations of ship emission impact on atomspheric pollution are studied with emphasis to compare the simulation with reality analyzed by means of flight measurement during the field campaign. In framework of the project the modeling studies are supposed to support the field campaign as well. The sensitivity of the impact on air quality and composition is analyzed as well with respect to ship emissions.

Regional Climate Change Impacts on Air Quality in CECILIA EC 6FP Project

Recent studies show considerable effect of atmospheric chemistry and aerosols on climate on regional and local scale. For the purpose of qualifying and quantifying the magnitude of climate forcing due to atmospheric chemistry/aerosols on regional scale, the development of coupling of regional climate model and chemistry/aerosol model has been started recently on the Department of Meteorology and Environmental Protection, Faculty of Mathematics and Physics, Charles University in Prague, for the EC 6FP Project QUANTIFY and finally for EC 6FP Project CECILIA. One of the project objectives, aiming to study climate change impacts in Central and Eastern Europe based on very high resolution simulations using regional climate models (RCM) in 10 km grid, is dealing with climate change impacts on and interaction to air quality. For this coupling, existing regional climate model and chemistry transport model are used. Climate is calculated using model RegCM and ALADIN-Climate while chemistry is solved by model CAMx. Climate change impacts on large urban and industrial areas modulated by topographical and land-use effects which can be resolved at the 10 km scale, are investigated by CECILIA as well. Meteorological fields generated by RCM drive CAMx transport, chemistry and a dry/wet deposition. A preprocessor utility was developed for transforming RegCM provided fields to CAMx input fields and format. As the first step, the distribution of pollutants can be simulated off-line for long period in the model couple. There is critical issue of the emission inventories available both for present and scenarios runs as well as cross-boundary transport for regional simulations. The next step is the inclusion of the radiative active agents from CAMx into RCM radiative transfer scheme to calculate the changes of heating rates. Only the modification of radiative transfer due to atmospheric chemistry/aerosols is taken into account first, the indirect effect of aerosols will be studied later. Ten years time slices for present, control and scenarios runs for mid- and end of century are supposed in framework of the project. Some sensitivity runs will be run in present climate.