ATMOSPHERIC CHEMISTRY

Author: TORO GOMEZ MARIA VICTORIA.
Year: 2003.
University: POLITÉCNICA DE CATALUÑA [www.upc.edu].
Place of defense: ENGINYERIA QUÍMICA ETSEIB.
Place of preparation: ETSEIB, EDIFICI H PLANTA 4 Campus SUD.

Summary: The Valle de Aburrá is a set of 11 municipalities near 3Â'000 .000 inhabitants among them, is the most populous Medellin (1Â'900 .000 inhabitants); his business is based on trade and textiles, food and chemistry. The city of Medellin is located in a valley closed with a complex topography and high mountains, which cause an entrapment of the pollutants that are emitted. In the Aburrá valley, it was found the existence of photochemical smog by monitoring air quality using a mobile station with automatic equipment for determining SOx, CO, NOx, particulate matter and O3. Since its implementation in September 1999, there have been episodes of especially high concentrations of ozone (up to 250 ppb). For this thesis work has been carried out an inventory of anthropogenic emissions and biogenic in a domain 40x40 km2 and spatial and temporal resolution of 1x1 km2 and one hour, respectively The results have reported an emission total of 81596 t / yr of pollutants in the first atmospheric layer which covers a height of 20 m above ground level (m sns), which interact stationary sources, the mobile sources and biogenic sources. In the upper layers that can reach 300 meters sns issuance due to the industries is 67660 t / year with greater involvement of particulate matter and SO2. In total in the valley are issued 149252 tpa where the largest proportion is due to vehicular traffic. The pollutant emission is more CO followed by the NOx and VOC. Subsequently it has been applied the model Eumac Zooming Model (EZM) at the University of Karlsrhue consisting of a model predictive mesoscale (MEMO), and a model of chemical reaction (MUSE) using data from globosonda obtained from measurements in Bogotá and the global model FINAL (FNL) to get the wind field, temperature and kinetic energy. These results are used as input data in conjunction with the inventory of emissions MUSE model to obtain the distribution of photochemical pollutants. For the simulation was required of the topography and the type of land use in each of the cells in the surface of a domain that covers a total volume of 144 x 202 x 6 km3. One scenario has been studied actual 48 hours characterized by high levels of production of ozone occurred over 23 and December 24, 1999. After simulating the scene by several cases, the results obtained allow on the one hand, describe the behavior of winds in an area of highly complex topographic and on the other hand, study the dispersion of pollutants. The ozone levels obtained by the model agree reasonably in several cases simulated. Finally, it has conducted an analysis of the chemical reaction mechanism that allowed for minimal relations between VOC and NOx emissions to limit the formation of ozone in the domain where the study has been developed.

Author: JIMENEZ GUERRERO PEDRO.
Year: 2004.
University: POLITÉCNICA DE CATALUÑA [www.upc.edu].
Place of defense: ETSEIB.
Place of preparation: ETSEIB, EDIFICI H PLANTA 10 Campus SUD.

Summary: High levels of air pollutants in the northeast of the Iberian Peninsula have a strong impact on both ecosystems as on human health. This region is particularly sensitive to pollution by ozone (O3), due to its complicated topography, which induces a flow structure that has important effects on the transport and transformation of pollutants photochemical. A pesar de esta complejidad, la utilización de modelos de calidad del aire multiescala y anidados se ha revelado como una herramienta útil a la hora de evaluar fenómenos relacionados con la calidad del aire en terrenos muy complejos. The model air quality third generation used to simulate the problems of air pollution in the north-east of the Iberian Peninsula is MM5-EMICAT2000-CMAQ, configured with high spatial resolution (1-2km) and temporal (1h). The meteorological model mesoscale MM5 was implemented in order to simulate the atmospheric circulations in a regional scale. EMICAT2000 was developed by Dr. Parra within the Environmental Modeling Laboratory, under the leadership of Dr. Baldasano, in order to estimate emissions of primary pollutants, and to provide the information required by the CMAQ chemical transport model. This model has been configured with different parametrizations to analyze its influence on the outcome of O3 tropospheric. After developing a methodology for comparing and selecting photochemical mechanism, the mechanism CBM-IV was implemented in CMAQ to represent the gas phase chemical and heterogeneous, since this mechanism introduced a performance medium and representative of the current state of knowledge in this field . The episode of photochemical pollution selected took place between 13 and 16 August 2000. This episode is a typical situation summer low gradient bárico with high levels of O3 in the entire Mediterranean basin that surpass the threshold of 180 mg m-3 in 2002/3/EC. The domain study covers an area of 272x272 km2 concentrated in the northeast of the Iberian Peninsula. The problems associated with the startup of the model and the generation of boundary conditions for the domain were solved using an approximation multiscale, performing simulations for the entire Iberian Peninsula and providing information to the domain of the northeast peninsula through procedures nesting unidirectional. The influence of initial conditions was minimized through a spin-up of 48 hours prior to the actual simulations, which reduces the impact of the initial conditions a factor below 10% in the case of O3. The application of high resolution is essential in order to describe the phenomena mesoescalares in very complex terrain. Certain peculiarities of small-scale appear when using a horizontal resolution of 2km and 16 layers vertical. With the proposed resolution, modeled MM5-EMICAT2000-CMAQ can be applied for regulatory purposes, it reaches accuracy requirements established by the USEPA for 2002/3/EC. The origin of the high levels of atmospheric pollution in the study area is determined by the overlap of varying scale circulations that can be described by a combination of global and regional models, as ECHAM5/MESSy and MM5-EMICAT2000-CMAQ respectively. The presence of high levels of O3 is the result of interactions between different processes in which dominates local photochemistry and dry deposition, basically.

Author: CASTILLO FERNÁNDEZ SONIA.
Year: 2005.
University: POLITÉCNICA DE CATALUÑA [www.upc.edu].
Place of defense: UNIVERSIDAD POLITÉCNICA DE CATALUÑA.
Place of preparation: MN1 MANRESA.

Summary: The atmospheric particulate matter can be delivered by a wide variety of sources of natural and anthropogenic origin which produces a wide variation in the characteristics of the particles in suspension. Besides the influence of emissions of particulate matter of anthropogenic origin on air quality, Southern Europe, and in particular Spain, is particularly affected by frequent episodes of invasion of air masses of natural origin from North Africa . These air masses besides producing promotions in the levels of suspended particles, being of natural origin may also produce health effects (breathing problems in the surrounding towns of North Africa, such as the Canary Islands), effects on the radiative balance Ground effects on ecosystems through atmospheric deposition, and reducing visibility. The main objective of this work focuses on the study of atmospheric particulate matter in two areas of study, the Canary Islands and the northeast of the Iberian Peninsula. THE proximity of these areas of study to North Africa, makes these two areas are ideal for the study of this type of particulate matter, and its influence on the levels and the variability of atmospheric particulate matter both areas. So are chosen stations regional fund, where there are no influences of local anthropogenic input, in order to know the influence they can have air masses transported over long distances, with particular interest being transported from North Africa. Moreover, in areas of urban background of the Canary Islands were also seeks to study the interaction of these air masses of natural origin with local pollutants. Finally, we try to show the physical and chemical processes which take place during the transport of these air masses from its source area to the two areas receiving, the Canary Islands and the northeast of the Iberian Peninsula.

Author: VICENTE FORTEA ANA BELEN.
Year: 2006.
University: JAUME I DE CASTELLON [www.uji.es].
Place of defense: E.S.DE TECNO. Y CIENCIAS EXPERI..
Place of preparation: ESCUELA SUPERIOR DE TECNOLOGIA Y CIENCIAS EXPERIMENTALES.

Summary: The high technological development achieved by our society carries have been introduced into the environment naturally aspirated a large amount of chemicals that cause pollution. This research analyzes the quality of the air we breathe in a heavily industrialized area, as is the town of Vila - real (Castellon), with the aim of sensitizing the public on the problem of air pollution and that measures must be taken to alleviate the effects of such pollution. The main objective is the integrated study, during the period 2001 to 2005, of one hand the origins and evolution of particulate matter (TSP and PM10) and the chemical elements it contains: arsenic, cadmium, nickel and lead , in order to develop statistical models for forecasting, and on the other side of the ambient air quality following the procedures and rules for the new European legislation, and that leads to the formulation of a plan of reorganization of atmospheric study area.

Author: MINGUILLON BENGOCHEA MARIA CRUZ.
Year: 2006.
University: JAUME I DE CASTELLON [www.uji.es].
Place of defense: INSTITUTO DE TECNOLOGIA CERAMICA.
Place of preparation: ESCUELA SUPERIOR DE TECNOLOGIA Y CIENCIAS EXPERIMENTALES.

Summary: There has been an in-depth study during the period 2002-2005 on the levels, composition and sources of particulate matter in ambient air in the area of ceramics Castellon. The average levels of PM10 ranged between 27 and 36 µ g/m3, with the majority component mineral matter, which involves up to 45% of the total mass of PM10. The main sources of PM10 identified are: ore (with high industry's contribution), road traffic, regional fund, industrial and marine aerosol; also has quantified the contribution to the mass of PM10 in ambient air from each source. As plotters of emissions ceramics in the area and period of study have identified the As, Pb, Zn, Zr, and Tl. Stresses the sharp decline in the levels of As, Pb and Zn since early 2004, reflecting the implementation of corrective measures in some industrial plants, mainly ovens manufacturing chips. There were also quantified emissions from the ceramic industry in the area and the potential for reduction. All this has set targets for reducing between 3 and 5 mg/m3 of PM10 in urban areas, mainly based on the reduction of mineral fraction.

Author: VILDARRAZ SARALEGUI MARÍA JOSEFA.
Year: 2006.
University: PÚBLICA DE NAVARRA [www.unavarra.es].
Place of defense: DEPARTAMENTO DE QUÍMICA APLICADA.
Place of preparation: UNIVERSIDAD PÚBLICA DE NAVARRA.

Summary: The fundamental objective of this work will be the preparation, determination of the physicochemical properties and evaluation of the activity of platinum catalysts supported for the removal using catalytic oxidation of volatile organic compounds (VOCs). The VOCs are a class of air contaminants growing importance, which together with nitrogen oxides are involved in the problems of tropospheric ozone (photochemical smog). It produced a series of catalysts Pt (2% by weight) considering various media and salts of the metal precursor. It departed from commercial carriers (SiO2, gamma-Al2O3, alfa-Al2O3, MgO, SiO2-AlO3). It took into account the character or not chlorinated precursor salts [Pt (NH3) 4] Cl2 H2O, or Pt (NH3) 2)] (NO2) 2 and the use of a non-aqueous salt with Pt (acac) 2. As reference materials were tested commercial Pt catalysts dispersed on alumina. The physicochemical characterization was carried out by adsorption -desorción of Ns to -196 ° C, the X-ray Diffraction (XRD), temperature programmed reduction (RTP) and quisisorción CO to 35 ° C. The texture of the catalysts did not vary significantly with respect to the media. By XRD was identified in all Pt metal catalysts. The analysis of the diffraction peaks indicated a low initial dispersion of Pt, with values in the average size of crystalline between 14 and 60 nm. The results of RTP showed consumption of H2 very low, with relations H2/Pt generally lower than 1, which confirms along with resutlados of XRD, that the majority of Pt catalysts present in the state is in cash. The impact registered at lower temperatures were perceptible only with the catalysts prepared Pt (NH3) 2 (Nos.) 2 and could be allocated to the reducicón of PtO and alfa-PtO2. The effects recorded at higher temperatures were appreciated in all catalysts, suggesting species that have established a strong interaction with the media. The results of quimisorción CO on the catalysts previously reduced with H2 at 500 ° C confirmed the low dispersion of Pt, with values in the range of 1 to 32%. Stresses the catalysts prepared with Pt (NH3) 2 (NO2) 2 and supported on gamma-Al2O3 with a dispersion of 32%. The dispersions lowest coincided with the lowest consumption of H2 in experiments RTP, for the catalysts prepared Pt (NH3) 4) Cl2H2O, particularly those supported on SiO2 and SiO2-Al2O3. In a first phase was studied the effect of different variables operating in the ignition curves for the complete oxidation of 2-butanona, with the Pt catalyst (Cl) / gamma-Al2O3. There was a significant influence of some variables in the form of curves of ignition. The curves depart at low conversions how sigmoidea characteristics, and discrepancies occur between conversions as it is calculated through the formation of CO2 or consumption 2-butanona. This effect is accentuated if it increases the time space, if the reaction is initiated at low temperatures without prior contact with the stream feeding the catalyst, or whether pretreatment of the catalyst is in the air. The only reaction products were CO2 and H2O, and the results suggest the involvement of phenomena retention of VOCs in the media and / or certain centers linked to Pt. The results of the behavior of the catalysts in the combustion of 2-butanona, have shown a pioneering influence of salt and support. It has been found less effective for the catalysts prepared from salt containing chlorine, however this effect depends on 8 the natu 4d4 nature of the stand, being lower for those catalysts with a very low dispersion, especially for the catalyst supported on SiO2 which is not observed this effect. The catalyst supported on SiO2 seems to retain the intrinsic catalytic activity, presenting a distinct character. In general, low dispersion is beneficial for the activity, but is also dependent influence is the type of support. The acidity of the medium, which promotes the state's metal catalyst is also positive. All catalysts had high stability and selectivity.