EUPHORE chamber

Outdoor simulation chamber EUPHORE Solar UV/VIS Atmospheric simulation Brockmann et al. (1996)... 

The experiments presented here were carried out in the outdoor simulation chamber EUPHORE in Valencia, Spain. This facility and the analytical equipment used for the measurement of selected trace gases are described in detail by Becker (1996) as also Barnes and Wenger (1998). 

No quantum yield data have been reported for processes (I) or (II), but the apparent y-values for toluene oxide/2-methyloxepin disappearance have been determined in the European outdoor chamber (EUPHORE) in Valencia, Spain (Klotz et al., 1998b). The ratio y(CH3C6H50)//(N02) was measured to be (3.99 0.48) x 10 . Hence, for conditions with y(N02) = 8.0 x 10 , y(CH3C6H5O) 3.2 x 10 s ... 

Two other chambers were built in Germany, at the same time, for the study of aerosol processes. Already in 1986, Zetzsch and coworkers built in Hannover a 3000 1 Duran-glass indoor chamber, covered inside with FEP, and irradiated by solar simulators. This facility has recently been moved to Bayreuth. In 1990, Schurath and co-workers (see contribution in this book) built in Karlsruhe a 84 m stainless steel chamber called AIDA, which could be operated between -90 and +60 °C. EUPHORE will be described later in more detail. Other groups also now operate medium sized chambers Baltensperger in Zurich, Wenger in Cork, Le Bras in Orleans, Herrmann in Leipzig, Hjorth in Ispra and Doussin in Paris. 

An example of the good agreement which has been obtained in the EUPHORE chamber between measured OH radical profiles using the PAGE technique (Pilling, M. J. et al., 2003) and the OH radical concentration in the chemical system calculated from the decay of toluene is shown in Figure 24. 

Wirtz, K. Recent Investigations on Aerosol Formation in EUPHORE Chamber. Presented at the NATO EST-ARW Workshop on Environmental Simulation Chambers Application to Atmospheric Chemical Processes, Zakopane, Poland, October 1-4 (2004). 

The problems associated with calculating photolysis rates can be overcome by the experimental determination of j values in outdoor simulation chambers, such as the European Photoreactor (EUPHORE), in Valencia, Spain (Becker, 1996). The decay of an aldehyde when irradiated by natural sunlight can be measured directly by FTIR spectroscopy or gas chromatography and the j values determined from a simple first order kinetic plot in the form of equation (III) ... 

Experiments were performed in Chamber B of the EUPHORE facility. Reactants were introduced into the chamber by gently heating a known amount of the compound in a glass impinger and flushing the vapour into the chamber via a stream of purified air. Concentrations ranging from 131 to 511 ppbv of reactant were used during different experiments. The... 

About 580 actinic flux spectra recorded under different meteorological conditions (clear sky, partially cloudy or overcast) in the EUPHORE smog chambers, have been used to calculate the photolysis frequencies for various small carbonyl compounds that are considered to be important from the atmospheric chemistry point of view. The results are presented here. 

To obtain a clear dependency a statistical treatment of all the calculated photolysis frequencies, derived from all the actinic spectra recorded in the EUPHORE chamber has been performed. Figure 3 shows an example of the complete dataset for acetaldehyde. The statistical treatment has allowed a clear dependency between the calculated photolysis frequency and the solar zenith angle to be established. The result obtained for acetaldehyde statistical treatment after is presented graphically in Figure 4. The error bars represent the statistical (la) error only. Photolysis frequencies have been calculated in the range of 19 to 71.5 solar zenith angles for 17 carbonyl compounds. The calculated photolysis frequencies obtained for the different zenith angles as derived from all the EUPHORE actinic flux spectra measurements are presented in Table 1. 

Figure 3. Calculated photolysis frequency profile for one year derived from data recorded using the EUPHORE outdoor chamber.

Table 1. Calculated photolysis frequencies for carbonyl compounds (in s ) at different zenith angles derived from the EUPHORE chamber measurements.

In Table 3 the mean of the all calculated photolysis frequencies for the various compounds obtained from the analysis of the actinic flux measurements performed using EUPHORE chamber facilities is compared with results from other similar studies. In the estimates a quantum yield of unity has been assumed. 

In the present work a large set of actinic spectra recorded in the EUPHORE chamber under various atmospheric conditions has been obtained and used for the calculation of photolysis frequencies of 17 organic carbonyl compounds. From a statistical analysis of the photolysis frequencies calculated for the compounds an analytical form for Jfd) has been derived. For unsaturated compounds (methyl vinyl ketone, methacrolein, acrolein and crotonaldehyde) < ) g is negligible, although those cxompounds possess absorption spectra reaching the near visible. 

The degradation schemes of four aromatic hydrocarbons benzene, toluene, /7-xylene and 1,3,5-trimethylbenzene, have been updated on the basis of new kinetic and mechanistic data from current literature and conference proceedings and are available as part of the latest version of the Master Chemical Mechanism (MCMv3.1) via the MCM website thttn //mcm.leeds.ac.uk/MCM). The performance of these schemes concerning ozone formation from tropospheric aromatic oxidation has been evaluated using detailed environmental chamber datasets from the two EU EXACT measurement campaigns at EUPHORE (EXACT I - September 2001 and EXACT II - My 2002 (Pilling et al, 2003)). 

Another problem encountered in the aromatic photosmog experiments was the difficulty experienced in detecting appropriate amounts of y-dicarbonyls under atmospheric conditions, even using a comprehensive 2D-GC technique (Hamilton et al., 2003). Therefore, improved detection techniques need to be investigated in order to quantify the amounts of y-dicarbonyls formed in these systems. Nevertheless, the EUPHORE chamber dataset on unsaturated y-dicarbonyls provides an important resource for testing future mechanism developments and the work presented here highlights issues that require further investigation. 

Although the entire MCM has been tested in atmospheric models, and through intercomparison with the results of chamber-validated mechanisms (e.g. Derwent et al, 1998 Jenkin et al, 2002), it has only been partially tested using environmental chamber data. It has been used in a number of studies involving die European Photoreactor (EUPHORE) in Valencia (EUPHORE, 2002), providing the basis for validation of the mechanisms for selected VOC. MCM v3 chemistry has thus already been tested for the photo-oxidation of a-pinene-NOx mixtures at comparatively low NOx concentrations (Saunders et al, 2003). The aromatic mechanisms in MCM v3 and MCM v3.1 have also been evaluated against a set of smog-chamber experiments the evaluation was focused on four representative species of the... 

Dodge (2000) wrote an extensive review on large and small simulation chambers. Gas-phase reactions of isoprene were investigated in virtually all faeilities - SAPHIR in Jtilich (formerly TASK, 370 m ), EUPHORE in Valencia (200 m ), UNC (University of North... 

This paper describes a project that was designed to study the products from sunlight, ozone, HO radical, and NO3 radical-initiated reactions (the latest in the dark) of diesel emissions with the aid of an environmental simulation chamber, under realistic ambient conditions (dilution in the range of 1 300 - 1 400). The European Photoreactor in Valencia, Spain, (EUPHORE) which is currently one of the largest (approximately 200 m ) and best equipped outdoor simulation chambers in the world, is employed for this study. 

The EUPHORE chambers in Valencia, Spain, are described in detail elsewhere (Becker, 1996). Briefly, there are two chambers, each consisting of a half-spherical Teflon bag with a volume of about 204 m (see Figure 1). The chambers are protected against atmospheric influences by two half spherically shaped protective housings. The inlet and... 

The test matrix that will be carried out in the EUPHORE chamber is shown in Tables 1 and 2. These series of tests provide experiments that will examine the effects of aging, photolysis, HO, O3 and the NO3 radieal (in the dark) on the eomposition of diesel exhaust. The experiments are divided into dark (Table 1) and light (Table 2) exposures test matrixes. The dark experiments D-1, D-2, and D-5 provide baselines for other experiments. Experiment D-3 investigates the effeets of O3 on diesel exhaust in the dark and experiment D-4 allows the effect of the NO3 radical on diesel exhaust to be studied. Dinitrogen pentoxide is used as a source of NO3 radicals. N2O5 is prepared by reacting ozone with NO2 direetly in the chamber. 

The experiments performed in the EUPHORE smog chamber were simulated using a simple box model, including gas-phase chemistry only. The model described all experiments with high accuracy. Sensitivity analyses were carried out in order to explain the observations. 

Under Romanian-German-Spanish collaboration, experimental investigations of the gas-phase reactions of the NO3 radical with a series of benzenediol compounds were performed. The experiments were carried out in two chamber systems with in situ FT-IR (Fourier Transform -Infrared Spectroscopy) detection of reactants a 1080 1 quartz glass reactor at the Bergische University Wuppertal and in the EUPHORE outdoor smog chamber facility in Valencia/Spain. The kinetics of the reaction of NO3 radicals with three benzenediols using a relative kinetic technique have been investigated. 

Within the frame of the EU EXACT project (Romania, Germany, France and Spain), studies of the mechanisms of Secondary Organic Aerosol (SOA) formation from the photooxidation of aromatic hydrocarbon systems were performed. Experiments were carried out in the EUPHORE chamber facility. 

Under collaboration between FC, UI and the Bergische University Wuppertal, experimental studies of the atmospheric chemistry of C3 to C5 alkyl iodides have been performed in the EUPHORE outdoor chamber in Valencia, Spain. The kinetics and mechanism of the reactions of O atoms with alkyl halides have also been investigated. 

Among these decomposition processes, formation of OH radicals and H atoms are important in atmospheric chemistry. The yield of OH has been obtained by experiments with tracers or direct measurements with LIF method (Paulson et al. 1999 Rickard et al. 1999 Kroll et al. 2001), and the lUPAC subcommittee recommends (OH) = 0.16 (Atkinson et al. 2006). A recent value by the LIF detection using the EUPHORE chamber (see column in page 278) is (OH) = 0.17 0.09 agreeing with the above recommendation (Alam et al. 2011). As for the reaction pathway of HCO + OH, existence of a direct decomposition path, reaction (5.89) has also been suggested in addition to the path via dioxirane mentioned above (Alam et al. 2011). Information on the OH yields in the reactions of OH with alkene other than C2H4 will be described in Sect. (7.2.4). 

Zador, J., Zsely, I.G., Turanyi, T., Ratto, M., Tarantola, S., Saltelli, A. Local and global uncertainty analyses of a methane flame model. J. Phys. Chem. A 109, 9795-9807 (2(X)5b) Zador, J., Turanyi, T., Wirtz, K., Pilling, M.J. Uncertainty analysis backed investigation of chamber radical sources in the European Photoreactor (EUPHORE). J. Atmos. Chem. 55, 147-166 (2006a)... 

G6mez Alvarez et al. coupled PTR-MS with the European PHOtoREactor (EUPHORE) atmospheric simulation chamber (Valencia, Spain) to provide experimental confirmation of the dicarbonylic mechanism in the photooxidation of toluene and benzene [189]. The particular benefit of PTR-MS in this context is its relatively fast response time, which provides data that can be tested against a Master Chemical Mechanism (MCMv3.1) model. Differences in mass spectral fragmentation patterns also allowed PTR-MS to distinguish between cis- and fraws-butenedial, which are two of the products resulting from the photooxidation process. 

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