Downscaling air quality

SUDPLAN Newsletter 1 (December 2010): To accurately describe the future air quality in European cities will we build a system where it will be possible to nest pan-European models and local urban-scale air quality models.

Climate change is together with emission changes expected to result in changed air quality across Europe. In most cases is emission changes most important but for some species can climate change be as important for the future air quality in a city.

Ozon
A simulation of average number of days per year with daily maximum of running 8-hour concentration exceeding 120 ug/m3 in a future climate. Left: present climate, middle: 2021-2050, right 2071-2100.

Air quality in a city is also the result of emissions from the city itself and from long-range transport of air pollution from regions far away. To accurately describe the future air quality in European cities will we build a system where it will be possible to nest pan-European models and local urban-scale air quality models.

The modelling systems will be able to simulate the results of different climate change scenarios and different emission scenarios (both in Europe and in the city itself). The urban models will benefit from the detailed emission and population data that is typically available, and they will be fed by meterology from different climate realisations.
 
Air pollutants entering the city from other parts of Europe will be provided by already performed simulations that will simulate the tendency of air quality in Europe following climate change and estimated emission changes across the region, see figure.

Demanding simulations

The simulations are very time- and data demanding and an unlimited execution of models is not advisable. The downscaling will also include tools to analyse and visualize the results in various ways, in order to better communicate the results to non-scientists.

The down-scaled predictions of future air quality in the selected cities are novel and high quality science and we are preparing several scientific papers detailing the results and explaining the methods.