The thesis examines the international taxation rules of the Common Consolidated Corporate Tax Base (CCCTB) and their interaction with third-country corporate tax practice. The aim is to assess the effectiveness of the CCCTB vis-à-vis third countries, with Egypt as a practical example. The CCCTB has the potential to reduce corporate tax obstacles faced by businesses in the EU in having to comply with up to twenty seven different domestic systems for determining their taxable profits. However, the international taxation rules of the CCCTB system are likely to have an impact on the corporate tax practice in third countries, and may conflict with existing bilateral tax treaties concluded between CCCTB-Member States and third countries. The discussion presents a detailed analysis of the CCCTB’s unilateral framework for the avoidance of double taxation and for the protection of the common consolidated tax base. It reveals that, by means of ordinary credit and exemption methods provided in the CCCTB Directive, international double taxation will be eliminated in relation to third countries. Furthermore, the CCCTB’s anti-abuse rules are effective in protecting the common tax base and in eliminating non-double taxation. Nevertheless, the unilateral measures are in conflict with a number of important provisions of bilateral tax treaties, based on the OECD Model, concluded between the potential CCCTB-Member States and third countries. Egypt exemplifies this – but the problem is generic. These conflicts between the CCCTB and OECD Model bilateral treaties are detrimental to the effective functioning of the CCCTB system vis-à-vis third countries, and need to be redressed. This thesis suggests a simple and practical solution - replacement of the bilateral tax treaties between CCCTB-Member States and third countries with a multilateral tax treaty to be concluded between every third country and all CCCTB-Member States.

L'objectif de cette thèse est le développement et la validation d'un modèle numérique de la dynamique des particules en mélange externe et résolu en taille. Afin de suivre plusieurs compositions chimiques par classe de tailles, une nouvelle approche est présentée dans laquelle la composition chimique des particules est elle-même discrétisée suivant la fraction d'un ou plusieurs des constituants chimiques (e.g. suie, sulfate). Cette approche a pour but de mieux simuler l'évolution d'une population de particules à l'échelle locale et de particulariser des compositions chimiques typiques de certaines sources. Dans l'atmosphère, les particules interagissent essentiellement entre elles et avec les polluants gazeux par coagulation et condensation/évaporation. La première partie de la thèse a été consacrée à l'élaboration du modèle pour la coagulation, processus physique qui s'avère le plus complexe à modéliser selon notre approche du mélange externe. Dans un premier temps, les équations de la coagulation en mélange externe sont présentées et discrétisées suivant un nombre arbitraire de classe de tailles et de compositions chimiques. Plusieurs simulations numériques ont ensuite été effectuées avec ce modèle sur un même cas d'étude, en utilisant deux, trois et quatre composants chimiques. On vérifie à chaque fois que les résultats de la simulation numérique en mélange externe sont cohérents avec ceux du mélange interne du cas d'étude. Les résultats de ces simulations permettent d'apprécier l'effet de mélange de la coagulation qui produit, à partir de particules monocomposées, des particules bicomposées et tricomposées. Étant donné la complexité croissante d'un tel modèle, une attention toute particulière a été portée à l'implémentation numérique et à l'optimisation des algorithmes choisis. L'extension de cette approche à la condensation/évaporation constitue le prochain développement de ce modèle, nous en posons les bases théoriques en annexe. S'il existe aujourd'hui des données de mesure résolues en taille (SMPS), il n'y en a pas encore qui puissent être réellement validantes pour ce modèle de mélange externe, c'est-à-dire qui distinguent quantitativement plusieurs compositions chimiques par classe de taille. Aussi, dans la seconde partie de la thèse, nous avons envisagé le protocole d'une expérience en chambre permettant de mettre en évidence le mélange par coagulation de deux populations de particules de compositions différentes et d'apporter des données validantes pour le modèle développé. Deux séries d'expériences ont été menées, la première dans la chambre de grand volume CESAM et la seconde, dans le réacteur de petit volume de l'INERIS. La première série a mis en évidence l'homococagulation de chaque distribution polydispersée prise séparément et dans une moindre mesure, l'hétérocoagulation des deux distributions de nature différentes (NaBr et KBr) entre elles. La seconde série a montré la possibilité d'observer simultanément deux distributions monodispersées de particules de compositions différentes (CaSO4 et KBr), prérequis pour ce cas. Au final, les résultats de mesure se sont avérés insuffisants pour produire des données validantes pour le modèle, à cause du trop grand écart-type des distributions polydispersées dans la chambre de grand volume et à cause du dépôt au paroi qui domine dans le réacteur de petit volume. Des analyses au microscope électronique ont cependant attesté de la présence de particules issues de la coagulation entre les deux natures. A la suite des différentes expériences menées, nous revenons sur le protocole envisagé et proposons quelques pistes d'améliorations

La connaissance des sources primaires (combustion des énergies fossiles, combustion de la biomasse, éruptions des volcans, etc.) et secondaires (oxydation des composés organiques volatils (COV) suivie de la condensation formant des composés organiques particulaires) de l'aérosol organique ainsi que la caractérisation et la quantification de sa composition chimique restent un défit majeur, en particulier dans la région du Moyen Orient où les études de caractérisation de l'aérosol organique n'existent pas jusqu'à présent. Le Liban, un pays du Moyen Orient qui se situe au bord du bassin méditerranéen, représente un bon exemple pour la caractérisation des aérosols organiques dans cette région. Les travaux menés durant cette thèse s'inscrivent dans un objectif de l'étude de la qualité de l'air à Beyrouth (la capitale du Liban) en se concentrant plus spécifiquement sur les aérosols organiques. Tout d'abord, cette thèse a permis le développement d'un inventaire des émissions pour les gaz et les particules pour le Liban avec une résolution spatiale de 5 km x 5 km et pour la capitale Beyrouth avec une résolution spatiale de 1 km x 1 km. Les résultats obtenus indiquent que le transport routier est la source majoritaire responsable des émissions de monoxyde de carbone (CO), d'oxydes d'azote (NOX) et de composés organiques volatils non méthaniques (COVNM), tandis que les industries et les centrales électriques sont les principaux émetteurs des émissions de dioxyde de souffre (SO2) et des particules primaires. Ensuite, afin de caractériser les concentrations des polluants et plus spécialement la fraction organique des particules, deux campagnes de mesures intensives de 15 jours chacune ont été menées sur un site semi-urbain situé dans la banlieue de Beyrouth. Une première campagne estivale s'est déroulée en juillet 2011 et une deuxième campagne hivernale en février 2012. Ces campagnes, qui s'inscrivent dans le cadre du projet ECOCEM (Emission and Chemistry of Organic Carbon in East Mediterranean Beirut) ont permis une spéciation moléculaire et une catégorisation des sources en été et en hiver de l'aérosol organique au site de mesures où les campagnes ont été menées. En été, les précurseurs biogéniques tels que les monoterpènes et les sesquiterpènes qui aboutissent à la formation des aérosols organiques secondaires biogéniques sont la principale source à cause de l'insolation intensive et les températures élevées qui favorisent les émissions et les réactions de photo-oxydations. En hiver, la combustion de la biomasse est la principale source en raison de la combustion du bois dans le secteur résidentiel pour le chauffage. Enfin, les concentrations ambiantes des polluants à Beyrouth ont été simulées durant le mois de juillet 2011 à partir de données de l'inventaire des émissions développé dans le cadre de cette thèse en utilisant le modèle de chimie-transport Polyphemus/Polair3D. Les concentrations de polluants simulées avec le modèle ont été comparées aux concentrations mesurées durant la campagne estivale afin d'évaluer le modèle. Les résultats obtenus révèlent que le modèle est capable de simuler de manière satisfaisante les concentrations d'ozone (O3), de NOX et la plupart des composés présents dans les particules fines. Les différences entre le modèle et les mesures peuvent résulter des incertitudes dans les données d'entrée qui ont une très grande influence sur les sorties du modèle. Pour cela, une réduction des incertitudes engendrées par les données d'entrée et plus spécifiquement celles liées à l'inventaire des émissions est nécessaire. Par ailleurs, des mesures chimiques sur plusieurs sites sont aussi nécessaires dans le futur afin de mieux évaluer les simulations des concentrations de polluants / The chemical composition of PM2.5 includes both organic and inorganic compounds. Organic compounds, which constitute a significant fraction of the PM2.5 mass, can be emitted directly as primary aerosol from sources such as fossil-fuel combustion, biomass burning, and natural biogenic emissions, or formed in the atmosphere via chemical reactions leading to secondary organic aerosol (SOA) formation. SOA, which account for 20 – 80 % of total organic aerosol, are currently a major source of uncertainty in air quality modeling. The identification and quantification of the chemical composition of the organic fraction of PM2.5 and its source apportionment are of great interest, especially in the Middle East region where data on organic aerosols are currently lacking. Lebanon, a small developing country in the Middle East region located on the eastern shore of the Mediterranean basin represents a good example for characterizing organic aerosols in this region. To address this issue, the air quality in Beirut (the capital city of Lebanon) was investigated with a focus on organic aerosols. First, an air pollutant emission inventory was developed for Lebanon with a spatial resolution of 5 km x 5 km and for Beirut with a spatial resolution of 1 km x 1 km. The results obtained show that the road transport sector is the major contributor to carbon monoxide (CO), nitrogen oxides (NOx) and non-methane volatile organic compounds (VOC) emissions, whereas fossil fuel-fired power plants and large industrial plants are the major contributors to sulfur dioxide (SO2) and primary particulate matter (PM) emissions. Then, two intensive 15-day measurement campaigns were conducted at a semi-urban site located in a Beirut suburb to characterize air pollutant concentrations. The first measurement campaign took place in July 2011 and the second in February 2012. Measurements included PM2.5, organic carbon (OC) and elemental carbon (EC) mass concentrations as well as a molecular characterization of organic aerosols. Using these data, a source apportionment of organic aerosols was conducted for summer and winter. In summer, biogenic precursors such as monoterpenes and sesquiterpenes were the major source of OC due to intensive solar radiation and high ambient temperatures that promote biogenic VOC emissions and photo-oxidation reactions. In winter, biomass burning was the major source of organic aerosols because of the intensive use of wood burning for heating. Finally, air pollutant concentrations in Beirut were simulated for July 2011 with the Polyphemus/Polair3D chemical-transport model (CTM). The emission inventory mentioned above was used as input to the model. Meteorological simulations were conducted with the Weather Research and Forecasting model (WRF) using different configurations and the configuration leading to the best agreement with the observations was used to drive the air quality simulations. The simulated air pollutant concentrations were compared to the measured concentrations collected during the summer measurement campaign. The results show that the model reproduces satisfactorily the concentrations of ozone (O3), nitrogen dioxide (NO2), carbon monoxide (CO), and the major components of PM2.5. The differences obtained between the modeled and measured air pollutants concentrations are due in part to uncertainties in input data. Future studies should address the reduction of uncertainties such as those of the emission inventory. In addition, measurement campaigns involving several sites are needed to better characterize air pollution in Beirut and provide a more complete database to evaluate simulated air pollutant concentrations

The effective air quality management in the heavy polluted areas has to be based on high-quality monitoring with properly designed monitoring network and targeted measurements, which provided information required to source apportionment. The thesis aim was to apportion sources of atmospheric aerosol based on highly time resolved data of mass concentration of size segregated aerosol, its temporal and spatial variability, elemental composition, OC/EC and size distribution of carcinogenic polyaromatic hydrocarbons. Sampling campaigns went during winter and summer in small settlement Březno by Chomutov, residential area Ostrava - Radvanice a Bartovice and Mladá Boleslav in the years 2008 - 2010, 2012, 2013. We determined mass concentrations of PM10, PM1-10, PM1.15-10 and PM0.15-1.5 and their size fraction ratios. Based on the size ratios, the source apportionment of fine fraction (PM0.15-1.15) with focus on PM0.34-1.15 is crucial. We examined seasonal and spatial variability of PM10, PM.2.5, PM1 and PM1-10. Based on the examination, we obtained representative highly-time resolved data with regards to season and sampling locality. We analysed dynamic of size distribution of particle-bond eight carcinogenic polycyclic hydrocarbons. Based on the results the source apportionment of PM0.34-1.15 is crucial....

Atmospheric aerosols deteriorate visibility and pose a significant risk to human health. The global fluxes of secondary organic aerosols (SOA) that form in the atmosphere from aromatic hydrocarbons are poorly constrained and highly uncertain. The lack of molecular tracers to quantify anthropogenic SOA (ASOA) in part limits the understanding of its abundance and variability, and results in a systematic underestimation of the role of ASOA in the atmosphere. The research presented in this thesis advances the knowledge about ASOA through the i) development of new and advanced methods to quantify potential ASOA tracers, ii) evaluation of their suitability as tracers for ASOA, and iii) application of the validated tracers to assess the spatial, diurnal and seasonal variation of ASOA in three urban environments. In this research, a greater understanding of the role of ASOA is gained through the expansion of tracers for SOA from aromatic hydrocarbons. An analytical method to quantify furandiones, which are produced in high yields from the photooxidation of aromatic hydrocarbons, was developed and enabled the first ambient measurements of furandiones. The optimized method allows for the simultaneous extraction of primary source tracers (e.g., polycyclic aromatic hydrocarbons, hopanes, levoglucosan) and other potential ASOA tracers (e.g., 2,3-dihydroxy-4-oxopentanoic acid [DHOPA], benzene dicarboxylic acids, and nitromonoaromatics). The systematic evaluation of potential ASOA tracers by their detectability, gas-particle partitioning, and specificity revealed that DHOPA, phthalic acid, 4-methylphthalic acids, and some nitromonoaromatics are good ASOA tracers because they are specific to aromatic hydrocarbon photooxidation, readily detected in ambient air, and substantially partition to the particle phase under ambient conditions. These tracers are thus recommended for use in field studies to estimate ASOA contributions to atmospheric aerosol relative to other sources. ASOA was determined to be a significant contributor to PM2.5 organic carbon (OC) in three urban environments. In the industrial Houston Ship Channel area in Houston, TX, ASOA contributed 28% of OC, while biogenic SOA (BSOA) contributed 11%. Diurnally, ASOA peaked during daytime and was largely associated with motor vehicle emissions. In Shenzhen, a megacity in China, 13-23% of OC mass was attributed to ASOA, three folds higher than BSOA. When China controlled the emissions from fossil fuel-related sources, the ASOA contribution to OC reduced by 42-75% and visibility remarkably improved. In downtown Atlanta, GA, ASOA contributed 29% and 16% of OC during summer and winter, respectively. ASOA dominates over BSOA during winter, while high biogenic VOC fluxes made BSOA the major SOA source in Atlanta, GA during summertime. These results indicate the high abundance of ASOA in urban air that has potential to be reduced by modification of anthropogenic activities. Overall, the work presented in this dissertation advances the knowledge about the abundance and variation of ASOA in urban atmospheres through the development of quantification methods and expansion of ASOA tracers. These tracers improve source apportionment of ASOA in receptor based models, which can ultimately aid in developing and implementing effective strategies for air quality management.

Non-Methane Hydrocarbons (NMHC) monitored in Roosevelt Utah including Benzene, Toluene, Ethylbenzene and Xylene (collectively known as BTEX) are associated with deleterious effects including cancer. This study was designed to assess the origin and effect of the toxicants and addressed two points: 1) Source identification using the USEPA’s Positive Matrix Factorization (PMF) and NOAA’s Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model and 2) A human health risk assessment based on ambient concentrations of BTEX collected at the Roosevelt site. Model fit indicated that the primary contributor to total NMHCs was local oil and gas operations and was supported by previous assessments. Assessment of ambient BTEX concentrations was associated with slightly elevated carcinogenic risk.

Ozone (O3) and particulate matter (PM) existing in the atmosphere have adverse effects to human and environment. Southeast Texas experiences high O3 and PM events due to special meteorological conditions and high emission rates of volatile organic compounds (VOCs) and nitrogen oxides (NOx). Quantitative knowledge of the contributions of different emissions sources to O3 and PM is helpful to better understand their formation mechanisms and develop effective control strategies. Tagged reactive tracer techniques are developed and coupled into two chemical transport models (UCD/CIT model and CMAQ) to conduct source apportionment of O3, primary PM, secondary inorganic PM, and secondary organic aerosol (SOA) and aging distribution of elemental carbon (EC) and organic carbon (OC). Ozone (O3) and particulate matter (PM) existing in the atmosphere have adverse effects to human and environment. Southeast Texas experiences high O3 and PM events due to special meteorological conditions and high emission rates of volatile organic compounds (VOCs) and nitrogen oxides (NOx). Quantitative knowledge of the contributions of different emissions sources to O3 and PM is helpful to better understand their formation mechanisms and develop effective control strategies. Tagged reactive tracer techniques are developed and coupled into two chemical transport models (UCD/CIT model and CMAQ) to conduct source apportionment of O3, primary PM, secondary inorganic PM, and secondary organic aerosol (SOA) and aging distribution of elemental carbon (EC) and organic carbon (OC). Models successfully reproduce the concentrations of gas phase and PM phase species. Vehicles, natural gas, industries, and coal combustion are important O3 sources. Upwind sources have non-negligible influences (20-50%) on daytime O3, indicating that regional NOx emission controls are necessary to reduce O3 in Southeast Texas. EC is mainly from diesel engines while majority of primary OC is from internal combustion engines and industrial sources. Open burning, road dust, internal combustion engines and industries are the major sources of primary PM2.5. Wildfire dominates primary PM near fire locations. Over 80% of sulfate is produced in upwind areas and coal combustion contributes most. Ammonium ion is mainly from agriculture sources. The SOA peak values can be better predicted when the emissions are adjusted by a factor of 2. 20% of the total SOA is due to anthropogenic sources. Solvent and gasoline engines are the major sources. Oligomers from biogenic SOA account for 30-58% of the total SOA, indicating that long range transport is important. PAHs from anthropogenic sources can produce 4% of total anthropogenic SOA. Wild fire, vehicles, solvent and industries are the major sources. EC and OC emitted within 0-3 hours contribute approximately 70-90% in urban Houston and about 20-40% in rural areas. Significant diurnal variations in the relative contributions to EC are predicted. Fresh particles concentrations are high at morning and early evening. The concentrations of EC and OC that spend more than 9 hours in the air are low over land but almost accounts for 100% of the total EC and OC over the ocean.

Atmospheric aerosols may be emitted directly as particles (primary) or formed from gaseous precursors (secondary) from different natural and anthropogenic sources. The highly populated South and East Asia regions are currently in a phase of rapid economic growth to which high emissions of carbonaceous aerosols are coupled. This leads to generally poor air quality and a substantial impact of anthropogenic aerosols on the regional climate. However, the emissions of different carbon aerosol components are still poorly constrained. Water-soluble organic carbon (WSOC) is a large (20-80%) component of carbonaceous aerosols that can absorb solar light and enhance cloud formation, influencing both the direct and indirect climate effects of the aerosols. A novel method for carbon isotope-based studies, including source apportionment, of the WSOC component of ambient aerosols was developed and tested for recovery efficiency and the risk of contamination using both synthetic test substances and ambient aerosols (paper I). The application of this method for the source apportionment of aerosols in South and East Asia shows that fossil fuel input to WSOC is significant in both South Asia (about 17-23%) highly impacted by biomass combustion practices and in East Asia (up to 50%) dominated by fossil energy sources (papers II, III, IV). Fossil fraction in WSOC in the outflow from northern China is considerably larger than what has been measured in South Asia, Europe and USA (paper IV). A trend of enrichment in heavy stable carbon isotopes in WSOC with distance the particles have been transported from the source is observed in the South Asian region (papers II, III). Dual-isotope (Δ14C and δ13C) analysis demonstrates that WSOC is highly influenced by atmospheric aging processes. / <p>At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Submitted.</p>

In this study, atmospheric levels and sources of VOCs at Aliaga industrial area was investigated. For this, VOC concentrations were measured at two monitoring stations through winter and summer campaigns in 2005 and 2006. Sampling stations were located in downtown Aliaga and downwind of industrial facilities, approximately 500 m to the south east of Horozgedigi village. After the summer sampling, another temporary station was installed in between PETKIM and T&Uuml / PRAS, named as T&Uuml / PRAS Station to generate T&Uuml / PRAS and PETKIM profiles. More than 50 species were measured in all stations. In all stations, toluene has the highest contribution to total VOC concentration. Toluene is followed by m,p-xylene and benzene. While higher concentrations of traffic related VOCs were measured at Aliaga station, VOCs from industrial solvents and industrial processes were higher at Horozgedigi station. The concentration levels in Aliaga and Horozgedigi are found to be comparable to the other industrial regions reported in the literature. Investigation of episodes, diurnal variations of VOCs and meteorological parameters showed that PETKIM and T&Uuml / PRAS emissions affect the concentrations levels at Horozgedigi and Aliaga stations. Source profiles of PETKIM and T&Uuml / PRAS are determined by using the T&Uuml / PRAS station data set. 2-methyl-hexane, benzene and 2,2,3-tri-methyl-butane+2,3-di-methyl-pentane are found to be good markers of PETKIM emissions. Ten different VOC sources were identified in the region. These were gasoline exhaust, diesel exhaust, natural gas use, gasoline evaporation, industrial emissions-1, natural gas construction, non-industrial solvent use, industrial emissions-2, PETKIM emissions, and mixed emissions from PETKIM and shipbreaking facilities.

In recent years, the air quality of Kinmen-Xiamen region has deteriorated gradually, and PM10 was always the worst air quality indicator. Particularly, high PM10 concentration has been observed in spring and winter. The objective of this study was to characterize the chemical properties of atmospheric aerosol particles sampled at Xiamen Bay located at the west coast of Taiwan Strait by sampling atmospheric particles and using chemical mass balance (CMB) receptor model for source apportionment, which indicated the difference of background and episode periods. Furthermore, this study applied HYSPLIT model to figure out the transportation routes of polluted air mass by backward trajectory. Seven particulate matter (PM) sampling sites at Xiamen Bay, three sites at Kinmen Island and four sites at metro Xiamen, were selected for this particular study. Particulate matter sampling included regular and intensive sampling. Intensive sampling was conducted to collect PM2.5 and PM2.5-10 with dichotomous samplers in the spring and winter of 2008 and 2009, while regular sampling was conducted to collect PM10 with high-volume samplers twice a month since March 2008. Results from PM sampling indicated that atmospheric particles had a tendency to accumulate in Xiamen Bay all year round, particularly in spring and winter. Five sampling sites inside the Xiamen Bay had relatively higher PM concentration than two sampling sites outside the Xiamen Bay. It suggested that local emission at the Xiamen Bay was superior to long-range transportation from the Northeastern Monson. A superimposition phenomenon was regularly observed during the episodes at Xiamen Bay. The most abundant water-soluble ionic species of PM were SO42-, NO3-, and NH4+ at Xiamen Bay, the major chemical species of PM were secondary aerosols (i.e. (NH4)2SO4 and NH4NO3). Crustal elements (e.g. Ca, Mg, Fe, and Al) and anthropogenic elements (e.g. Zn and Pb) dominated the chemical species of particles. Backward trajectory results indicated that polluted air mass originated from Asian continent moved directly to Kinmen-Xiamen region in winter and spring, while air mass originated from the southwestern and southeastern ocean did not pass polluted region in summer, which result in better air quality of Kinmen-Xiamen region in summer than those in winter and spring. Results from CMB receptor modeling showed that the major sources of atmospheric PM10 at Kinmen-Xiamen region were soil dust, secondary aerosol, petroleum industry, motor vehicle exhanst, iron and steel industry, cement industry, Diesel vehicle exhanst marine aersols, and vegetative burning. The stationary sources were the major contributor accounting for approximately 50% of PM10 in Kinmen. It suggested that atmospheric particles were mainly originated from cross-boundary transport rather than local emission sources since there are no such kinds of industrial factories in Kinmen.