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INTRODUCTION
The European PHOtoREactor was designed by a consortium of 7 research institutes from 4 countries within the EU. The EUPHORE simulation chambers are operated by the Mediterranean Center for Environmental Studies Foundation (CEAM). The Foundation was created in 1991 by the Generalitat Valenciana and Bancaja, with the support of the Secretariat of State for Universities and Research and the European Commission (DG Research). The CEAM Foundation is a Center of Applied Research and Technological Innovation, and it also operates as an associated unit of CSIC. The CEAM is conceived as a mutilidisciplinary center, focussing its performances on complementary thematic areas in which it provides internationally recognized expertise. The scientific activity of the Foundation is articulated in four research programmes: Atmospheric Pollution, Air Pollutant Effect, Forest Research and Meteorology-Climatology.
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DESCRIPTION OF THE RESEARCH FACILITY
The main objectives of the Atmospheric Chemistry area, within the Atmospheric pollution area, are: i) Investigation into the photochemical degradation of atmospheric pollutants and study of generated products which present a potential risk for health and environment. ii) Database development with international projection, iii) Validation and implementation of photochemical models. iv) Development and validation of new instrumentation, as well as improvement of the already existing one v) Exploitation of the EUPHORE smog chambers, for the development of research projects managed by the Foundation, as well as for other national and international institutions.
The Installation has two twin outdoor atmospheric simulation chambers. Each one consists of a half spherical Teflon bag with a volume of about 200m3. The chambers are made from a fluorine-ethene-propene (FPE) foil with a thickness of 0.13 mm whereby 32 individual segments are welded together to achieve the half-spherical form. This foil has a transmission of more than 80% for sunlight in the near UV and the visible range between 280 nm and 640 nm, which is the important range supplying the energy for the chemical reactions occurring in photo-oxidation processes in the troposhere. Teflon is a chemically inert material and provides the best choice to avoid uncontrolled reactions of the trace gases with the chamber walls.
The chamber is self-stabilising against wind distortions when operated with an excess pressure of 100-200 Pa. An internal framework made of epoxide resin tubes based on a half-spherical network construction keeps the foil in shape in the absence of excess internal pressure. The chamber floor consists of 32 symmetrically arranged aluminium panels covered with FPE foil, and an integrated rubber cord is used as a seal between the bag and the floor. One of the technical innovations is the refrigeration system integrated in the chamber floor, which compensates heating of the chamber air by solar radiation. Ports for input of the reactants and sampling lines for the different analytical instruments are located on the chamber floor.
Analytical instrumentation
The simulation chambers are equipped with a broad number of analytical instruments in order to analyse VOCs, O3, NO, NO2, PAN, organic nitrates, hydroperoxides and organic acids. For in-situ measurements highly sensitive and selective techniques such as LP-FTIR and LP-UV/VIS DOAS spectroscopy are available. For the sensitive analysis of reaction products several ozone and NOx monitors, as well as HCHO monitor, HONO-LOPAP monitor, PTRMS, GC-MS and GC-MS/MS systems can be employed for sampling the trace gas components directly from the gas phase, with pre-concentration techniques or solvent trapping. For the measurement of OH and OH2 radicals a Laser Induced Fluorescence LIF is available with its excellent potential for obtaining insight into radical formation and radical cycling processes, responsible for ozone and photo-oxidant formation. To measure aerosol formation from biogenic or anthropogenic precursor VOCs during oxidation, the EUPHORE installation is equipped with a SMPS system and a continuous-operating microbalance (TEOM) providing particle numbers and mass concentration. Other off-line techniques, such HPLC and LC-MS or GC-MS for the analysis of different range of compounds, both in gas and particle phase, are also available.
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