Using the European Photochemical Reactor (EUPHORE)
The ever-increasing industrialisation of European communities has a dramatic impact on the environment, resulting in air pollution with potential harmful effects on human health, agricultural production and water quality. Effective control measures against emissions of chemical species, which negatively affect air quality and climate change should be based on sound scientific investigations and understanding of atmospheric sciences. Answering this need, the MOST project focused on understanding the changes in atmospheric composition due to emissions changes related to EU directives. The key objective was to measure concentrations of chemically and radioactively active species such as ozone and aerosols. Particularly, particles and their precursors that form secondary aerosols coming from anthropogenic emissions changes and resulting from a change from traditional to oxygenated solvents were extensively studied. Having conducted a systematic investigation on the multiphase processes of oxygenated compounds, detailed and simplified degradation schemes were derived. These results coming from some laboratory studies were further validated with the aid of the outdoor EUPHORE smog chamber facility in Valencia, Spain. This environmental chamber offers working at ambient level conditions as far as the reactive nitrogen oxides concentrations are concerned. Unlike field studies or small laboratory chambers with artificial light sources the chamber allows better control of physical parameters and exclusion of meteorological effects. Therefore, data gathered during photochemical investigations can be more easily analysed in most cases. This is achieved through simulation of chemical processes in the smog chamber. Researchers are able to evaluate mechanisms under the low NOx concentrations as found in rural and downwind of urban areas. With the EUPHORE chamber the detailed degradation mechanism derived for single oxygenated compounds from laboratory data was tested. By employing a scanning mobility particle sizer connected to a condensation nuclei counter, aerosol size and number distribution were measured during the photosmog runs. The results enabled optimisation of unknown parameters and offered feedback to the laboratory studies. Moreover, they allowed validation of degradation schemes for all the generic oxygenated compounds under study. For more information, click at: http://most.univ-lyon1.fr/
