La biomasse représente l’une des principales alternatives à l’utilisation du pétrole dans la plasturgie. Grâce à leurs propriétés fonctionnelles, les caséinates sont une matière première prometteuse pour la fabrication de films plastiques pour des applications dans l’emballage biodégradable et hydrosoluble. La transformation du caséinate de sodium par les techniques habituellement utilisées dans la plasturgie a été démontrée. Des extrudats de caséinate plastifié au glycérol ont été obtenus au moyen d’une extrudeuse bi-vis corotative. La caractérisation physico-chimique du matériau obtenu a confirmé la thermostabilité de cette protéine et a montré la dépendance du comportement du matériau vis-à-vis de l’humidité ambiante. Pour une variation du taux d’Humidité Relative, de 40 à 90% et une augmentation de la concentration du glycérol, plastifiant hygroscopique, le matériau passe d’un état vitreux (rigide) à un état caoutchouteux (mou). Des films fins ont été ensuite réalisés, à partir des extrudats thermoplastiques, par extrusion gonflage. La perméabilité à la vapeur d’eau des films de caséinate de sodium a été étudiée et a montré que ces matériaux sont de mauvaises barrières à l’humidité. La deuxième partie a été consacré à l’étude de mélanges caséinate de sodium/caséinate de calcium d’un côté et caséinate de sodium/PBAT de l’autre. Le mélange des deux caséinates a permis d’augmenter la tenue mécanique du mélange, à partir de 50% de caséinate de calcium, et de retarder le transfert hydrique à travers le film. Dans le même sens, l’ajout du PBAT, a augmenté jusqu’à deux fois plus, le module d’Young des mélanges mais a baissé la résistance au transfert d’humidité du film à cause de l’incompatibilité des deux polymères / Biomass is one of the main alternatives to the use of oil in plastics field. Due to their various functional properties, caseinates are considered as an interesting raw material for making biodegradable and water-soluble packaging. The transformation of sodium caseinate by the processes used for synthetic plastics industry has been demonstrated. A corotating twin-screw extruder was used to get glycerol plasticized caseinate pellets. The physicochemical properties of the obtained material have confirmed the thermal stability of this protein and demonstrated the influence of surrounding moisture on material behavior. With the Relative Humidity varying from 40 to 90% and increasing the glycerol content, an hydrous plasticizer, the mechanical properties of sodium caseinate based materials changed from those of glassy (rigid) to rubbery (soft) plastics. The pellets were then taken over to make film using a blown-film extruder. The water vapour permeability of blown film was studied and showed that sodium caseinate based films are a poor moisture barrier. The second part dealt with the sodium caseinate blend. Sodium caseinate/calcium caseinate and sodium caseinate/PBAT blends was performed. Adding calcium caseinate, started from 50%, improved the mechanical properties and delayed hydrous transfer through the film. Concerning the sodium caseinate/PBAT blends, adding PBAT increased until twice more the material’s Young modulus but decreased the moisture transfer resistance because of the incompatibility between the two polymers

A composição química do material particulado fino (MP2,5) e MP10 foi determinado em três sítios representativos do estado de São Paulo: Cidade Universitária (SPA), Piracicaba (PRB) e São Luis do Paraitinga (MAT); e em duas outras cidades sul-americanas, Bogotá (BOG) e Buenos Aires (BAI). As coletas ocorreram nos anos de 2007, 2008 e 2009. Para caracterizar os sítios foram determinados íons inorgânicos, orgânicos e levoglucosano no MP coletado em filtros de fibra de quartzo. O material carbonáceo, sulfato, nitrato e amônio foram as espécies determinadas mais abundantes na massa do MP2,5 e MP10, sobretudo nas amostras dos sítios do estado de São Paulo. A contribuição destes componentes está associada à formação secundária das partículas atmosféricas nos centros urbanos. Entretanto, o cátion predominante das amostras nos sítios BOG e BAI foi o cálcio. Esta espécie no MP atmosférico, juntamente com o Mg2+, são atribuídos à ressuspensão de solo. Por meio dos estudos das trajetórias de massas de ar foi observada a influência de outras fontes sobre o material particulado local. A entrada de partículas provenientes de queima de madeira e biomassa em regiões urbanas foi associada à presença do levoglucosano, correlacionado com K+ e outros marcadores ambientais. O uso de ferramentas estatísticas, como as razões diagnósticas, as matrizes de correlações e análise de componente principal (ACP), contribuíram para a caracterização dos sítios estudados, distinguindo estatisticamente as emissões veiculares, das atividades agrícolas, industriais e queima da biomassa, entre outras. / The chemical composition of fine particulate matter (PM2.5) and PM10 was determined in three sites representative of the São Paulo State: University City (SPA), Piracicaba (PRB) and São Luis of the Paraitinga (MAT); and in two other South American cities, Bogotá (BOG) and Buenos Aires (BAI). The samples were collected in 2007, 2008 and 2009. In order to characterize the chemical composition of PM collected on quartz fiber filters, water-soluble ions and levoglucosan were determined. Carbonaceous material, sulfate, nitrate and ammonium were the most abundant species in the PM2.5 and PM10 samples, especially those from the São Paulo sites. The contribution of these components is associated with secondary formation of atmospheric particles in urban centers. However, calcium was the predominant cation of samples from BOG and BAI sites. PM atmospheric presence of Ca2+ and Mg2+ is attributed to soil dust. Through the studies air mass trajectories was observed the influence of other sources on the local particulate matter. The input of particles from burning wood and biomass in urban areas was associated with the presence of levoglucosan with K+ and other environmental tracers. The use of statistical tools such as diagnostic reasons, correlation matrices and principal component analysis (PCA), contributed to the characterization of sites studied. Therefore it was possible to distinguish statistically vehicle, agricultural activities, industrial and biomass burning emissions, among others.

A composição química do material particulado fino (MP2,5) e MP10 foi determinado em três sítios representativos do estado de São Paulo: Cidade Universitária (SPA), Piracicaba (PRB) e São Luis do Paraitinga (MAT); e em duas outras cidades sul-americanas, Bogotá (BOG) e Buenos Aires (BAI). As coletas ocorreram nos anos de 2007, 2008 e 2009. Para caracterizar os sítios foram determinados íons inorgânicos, orgânicos e levoglucosano no MP coletado em filtros de fibra de quartzo. O material carbonáceo, sulfato, nitrato e amônio foram as espécies determinadas mais abundantes na massa do MP2,5 e MP10, sobretudo nas amostras dos sítios do estado de São Paulo. A contribuição destes componentes está associada à formação secundária das partículas atmosféricas nos centros urbanos. Entretanto, o cátion predominante das amostras nos sítios BOG e BAI foi o cálcio. Esta espécie no MP atmosférico, juntamente com o Mg2+, são atribuídos à ressuspensão de solo. Por meio dos estudos das trajetórias de massas de ar foi observada a influência de outras fontes sobre o material particulado local. A entrada de partículas provenientes de queima de madeira e biomassa em regiões urbanas foi associada à presença do levoglucosano, correlacionado com K+ e outros marcadores ambientais. O uso de ferramentas estatísticas, como as razões diagnósticas, as matrizes de correlações e análise de componente principal (ACP), contribuíram para a caracterização dos sítios estudados, distinguindo estatisticamente as emissões veiculares, das atividades agrícolas, industriais e queima da biomassa, entre outras. / The chemical composition of fine particulate matter (PM2.5) and PM10 was determined in three sites representative of the São Paulo State: University City (SPA), Piracicaba (PRB) and São Luis of the Paraitinga (MAT); and in two other South American cities, Bogotá (BOG) and Buenos Aires (BAI). The samples were collected in 2007, 2008 and 2009. In order to characterize the chemical composition of PM collected on quartz fiber filters, water-soluble ions and levoglucosan were determined. Carbonaceous material, sulfate, nitrate and ammonium were the most abundant species in the PM2.5 and PM10 samples, especially those from the São Paulo sites. The contribution of these components is associated with secondary formation of atmospheric particles in urban centers. However, calcium was the predominant cation of samples from BOG and BAI sites. PM atmospheric presence of Ca2+ and Mg2+ is attributed to soil dust. Through the studies air mass trajectories was observed the influence of other sources on the local particulate matter. The input of particles from burning wood and biomass in urban areas was associated with the presence of levoglucosan with K+ and other environmental tracers. The use of statistical tools such as diagnostic reasons, correlation matrices and principal component analysis (PCA), contributed to the characterization of sites studied. Therefore it was possible to distinguish statistically vehicle, agricultural activities, industrial and biomass burning emissions, among others.

Ce travail est consacré à l'étude d'origine et signatures de la dépendance en concentration $\phi$ du paramètre de Flory $\chi _(eff)$ pour les polymères neutres solubles dans l'eau. Les trois versions du modèle à deux états qui ont été proposés pour expliquer le comportement de phase de Poly(oxyéthylène) dans l'eau mènent à $\chi _(eff)(\phi) $. Cette dépendance peut servir à tester la qualité des modèles: elle permet de distinguer entre les différents modèles et juger de la pertinence des paramètres impliqués. L'apparition de $\chi _(eff)(\phi)$ à partir des modèles alternatifs à un seul état est aussi discutée. Les signatures macroscopiques de $\chi _(eff)(\phi)$ sont illustrées avec l'exemple du gonflement des chaînes isolées et des brosses planes. La dépendance de $\chi _(eff)$ avec $\phi$ dans les systèmes à concentration uniforme a deux conséquences principales: entraînement du déplacement du croisement entre les régimes Gaussien et auto-évitant, et la possibilité d'une transition de phase du premier ordre pour les chaînes flexibles isolées. $\chi _(eff)(\phi)$ peut provoquer une séparation verticale de phase dans des brosses polymères qui implique la coexistence de deux phases de concentration finie. Cette approche est appliquée à l'interprétation d'un ensemble des résultats expérimentaux qui suggère que cet effet pourrait exister avec les brosses de Poly(N-isopropylacrylamide).

The search for alternatives to the fossil-based products has dramatically surged during past few decades primarily due to the problems associated with the scarcity of these sources and global environmental concerns. Among those many alternatives, exploitation of cellulose, as a raw material to develop novel products has been a constant attempt since it has never lost its both economic and industrial impact. Cellulose is known for its significant contribution as a raw material and as a fascinating sustainable macromolecule, which exhibits wide availability and versatile chemical reactivity to discover novel derivatives for broad range of applications. Conversion of cellulose C2/C3 secondary hydroxyl groups to dialdehyde groups in the presence of periodate is an extremely useful method for regioselective oxidation of cellulose and to activate the polymer for further derivatization. This thesis is primarily focused on synthesis and characterization of wide range of cellulose derivatives exploiting facile periodate oxidation methodology. The first study investigated the use of periodate oxidation as a potential method to synthesize a novel water soluble derivative of cellulose from bleached hardwood Kraft pulp. The work focused on the effect of periodate oxidation and sulfonation reaction on water solubility, morphology and structure of cellulose fibers. The results showed a significant increase in water solubility (2.85 -28.5 g/L) and complete change in surface morphology of the fibers due to the introduction of sulfonic acid groups. In the second study, the same reaction scheme was employed on bead cellulose to prepare anionic 2,3-disulfonated beads. Due to the presence of negatively charged sulfonic acid groups, the beads were found to be agglomerated in presence of cationic starch, exhibiting their future application in chromatographic separation. In the third study, model primary amine compounds such as methyl and butyl amines were grafted to nanowhisker surfaces following periodate oxidation and reductive amination. Then, based on the grafting procedure, in the following study, gamma aminobutyric acid (spacer) and syringyl alcohol (linker) was attached to periodate oxidized nanowhiskers to synthesize a novel drug delivery system. The final study investigated the application of periodate oxidized nanowhiskers as chemical cross-linkers to stabilize gelatin gels. It was concluded that the chemical cross-linking has a significant effect on relative increase in percentage of rigid protons, reduced water uptake ability and reduced pore size of the gels. Not only did the chemical cross-linking improve the storage modulus of the gels (150%) and but it also increased the thermal resistance until 50 oC.

Different aspects of natural organic matter composition and cycling have been studied using solid-state 13C and 31P Nuclear Magnetic Resonance (NMR) spectroscopy. Depending on the specific study, complementary analytical techniques such as elemental, isotopic and molecular analyses have also been applied. Samples from a variety of environments were examined including ocean waters, marine sediments and atmospheric aerosols. Studies from all these environments illustrate differences in natural organic matter composition resulting from various factors such as sources, cycling mechanisms and redox conditions. In the marine water column, organic matter of two different size fractions (dissolved and particulate) is found to have distinctly different bulk chemical and isotopic compositions. Overall, this indicates that particulate organic matter does not form from the simple physical aggregation of dissolved organic matter, and dissolved organic matter is not the primary source for particulate organic matter. Comparison of carbon and phosphorus compositional changes with depth in the ocean within the dissolved and particulate fractions reveals differences in cycling mechanisms. In the marine water column, selective mineralization of specific carbon compounds such as carbohydrates and amino acids occurs relative other species such as lipids. Whereas for phosphorus, the relative proportion of the different functional groups are unvarying with depth. In marine sediments, NMR spectroscopy reveals P cycling for specific phases such as polyphosphates is a function of sediment redox conditions. In atmospheric aerosols 13C NMR spectroscopy shows differences in water-soluble organic carbon composition from urban versus biomass burning sources. Urban aerosols have higher aliphatic and lower aromatic compound contents relative to samples derived from biomass burning. The results of these studies provide new insights into carbon and phosphorus cycling in the environment and demonstrate the capabilities of solid-state NMR as a tool for investigating natural organic matter composition.

In today s world, the need to limit the use of nonrenewable resources and the importance of recycling has been recognized. One important contribution of chemists toward the general goal of limiting their use is to find catalysts that can be reused and recycled thereby limiting the need for expensive metal precursors and metal waste. Strategies to recycle catalysts are multifold and range from the employment of soluble polymers as catalyst supports to the use of membrane-encapsulated catalyst. The use of soluble polymers as a support not only offers the advantage of being soluble under the catalytic reaction conditions but also, to be removable by changing the conditions of the surrounding media. Despite the great potential of these soluble supported catalysts, their use is very limited in today s synthesis. In addition, no set of rules have been established to guide the synthesis of efficient supported catalysts. In order to establish a tool box for the synthesis of supported catalysts, the study of several parameters such as the choice of the support and the choice and the stability of the catalyst are necessary. To establish this set of rules, a limited number of catalytic transformations, were studied. These catalytic reactions are the Heck-Mizoroki, Suzuki-Miyaura and Sonogashira coupling reactions. These transformations became fundamental for the synthesis of drugs and materials. The first and second chapters provide background information by describing and evaluating the main supports that were previously used for catalysts and the two main catalysts that are used in this thesis, the palladium pincer complex and the palladium N-heterocyclic complex. In chapter 3, the synthesis of a soluble polymer supported catalyst is described. The polymer chosen for the study is poly(norbornene), and the catalyst is a 1,3-disubstituted benzene ligand with sulfurs in the side-chains able to chelate to the metal center, better known as pincer ligand. These ligands are abbreviated by the three atoms that coordinate to the metal center, in this study, SCS. The metal used for the investigation of the activity of this supported pincer is palladium. The importance of the nature of the linkage on the stability of the Pd-SCS pincer complex has been reported in the literature, leading to the synthesis of Pd-SCS pincer complex tethered to the polymer via an ether and an amide linkage. The synthesized poly(norbornene) supported Pd-SCS pincer complexes were evaluated using the Heck transformation of iodobenzene with n-butyl acrylate. Kinetic studies and leaching tests using poly(vinyl pyridine) and mercury were carried out resulting in the conclusion that the active species during the catalysis is not the palladium pincer complex but a leached palladium (0) species. In chapter 4, Pd-PCP pincer complexes with the ether and amide tether were synthesized. Kinetic and poisoning studies were carried out resulting in a similar conclusion. Furthermore, 31P NMR experiments were conducted to investigate the unstability of the complex. Following this study, in-situ XAS as well as computational calculations were carried out. The conclusion from this sinvestigation argues that triethylamine is a key ingredient for the decomposition of the Pd-PCP complex. The overall conclusion from these two different studies is thta Pd(II) pincer complexes decomposes during the Heck reaction when triethylamine is used for the coupling of iodobenzene to n-butyl acrylate in DMF at 120 ºC. Stemming from this investigation, a reported more stable complex, Pd-NHC, was tethered onto poly(norbornene). The system was evaluated using Suzuki-Miyaura, Heck and Sonogashira reactions. Similar poisoning and kinetic studies were utilized to investigate the stability of the supported NHC Pd complexes. The result of this investigation suggests that supported Pd-NHC complexes are stable under Suzuki-Miyaura and Sonogashira but decompose under Heck conditions. However, when the system was recycled, a decrease in activity for the Suzuki-Miyaura transformation and solubility was observed. In chapter 6, gold monolayer protected clusters (MPC) were investigated as potential candidates as supports. To examine the potential of MPC as a support, a NHC-Pd complex was graphted onto the particles. To functionalize the gold nanoparticles, a new method was developed. Using azide moieties added to the gold nanoparticles, the catalyst was added via microwave assisted 1,3 dipolar cycloaddition. The system was evaluated using Suzuki-Miyaura transformations under microwave conditions. The system exhibited quantitative conversions for a variety of substrates. However, when the system was recycled, aggregation of the particles and decrease in catalytic activity was observed. In summary, this thesis describes the synthesis and evaluation of poly(norbornene) supported Pd-pincer and Pd-NHC complexes and of gold nanoparticles supported Pd-NHC complex. It also detail the combination of kinetic and poisoning studies developed to evaluate a potential supported catalyst.

It is well known that atmospheric aerosols provide the sites for forming cloud droplets, and can affect the Earth's radiation budget through their interactions with clouds. The ability of aerosols to act as cloud condensation nuclei is a strong function of their chemical composition and size. The compositional complexity of aerosol prohibits their explicit treatment in atmospheric models of aerosol-cloud interactions. Nevertheless, the cumulative impact of organics on CCN activity is still required, as carbonaceous material can constitute up to 90% of the total aerosol, 10-70% of which is water soluble. Therefore it is necessary to characterize the water soluble organic carbon fraction by CCN activation, droplet growth kinetics, and surface tension measurements. In this thesis, we investigate the water soluble properties, such as surface tension, solubility, and molecular weight, of laboratory and ambient aerosols and their effect on CCN formation. A mechanism called Curvature Enhanced Solubility is proposed and shown to explain the apparent increased solubility of organics. A new method, called Köhler Theory Analysis, which is completely new, fast, and uses minimal amount of sample was developed to infer the molar volume (or molar mass) of organics. Due to the success of the technique in predicting the molar volume of laboratory samples, it was applied to aerosols collected in Mexico City. Additionally the surface tension, CCN activity, and droplet growth kinetics of these urban polluted aerosols were investigated. Studies performed for the water soluble components showed that the aerosols in Mexico City have surfactants present, can readily become CCN, and have growth similar to ammonium sulfate. Finally, aerosols from three different polluted sources, urban, bovine, and ship emissions, were collected and characterized. The data assembled was used to predict CCN concentrations and access our understanding of the system. From these analyses, it was evident that knowledge of the chemical composition and mixing state of the aerosol is necessary to achieve agreement between observations and predictions. The data obtained in this thesis can be introduced and used as constraints in aerosol-cloud interaction parameterizations developed for global climate models, which could lead to improvements in the indirect effect of aerosols.

Textile reinforced concrete (TRC) is an innovative composite material, which is being intensely and practice-oriented investigated on national and international level. In the last few years this material has gained increasing importance in the field of civil engineering. In the context of the collaborative research project SFB 532 at the RWTH Aachen University, research was carried out to understand and to predict the behaviour of different yarn structures in fine grained concrete. Based on the results, innovative commingling yarns were made of alkali-resistant glass fibres and water soluble PVA. These hybrid yarns have an open structure, which improves the penetration of the textile reinforcement by the concrete matrix. Hence, the load bearing capacity of TRC structural elements was significantly improved. This paper presents a technique for the production of such commingling yarns for concrete applications. The mechanical properties of the new yarns are determined due to tensile stress tests. The bond behaviour of the commingling yarns was investigated by pull-out- and tensile stress tests on TRC-specimens. The results of the different tests are being presented and briefly discussed.

Aerosol are solid or liquid particles suspended in the atmosphere ranging in size from 10 3 to 102 m. Aerosol influence both the regional and global climate of the earth by its direct and indirect effect. Role of atmospheric aerosols on the radiative forcing of atmosphere is a matter of serious research for past few decades and still it remains highly uncertain as acknowledged by Intergovernmental Panel on Climate Change. Heterogeneous nature of aerosol both spatially and temporally makes it more complex in estimating radiative forcing compared to that of greenhouse gases. Compounding to the existing difficulty in determining the climate effects, changing aerosol concentration and nature of the aerosol further increases the complexity in determining its effects in both regional and global climate. Increasing aerosol loading is emerging to be an issue of major concern over several regions. The first step towards achieving this goal is by determining the trends in the physical and optical properties of aerosol over the globe. Main objective of the thesis is the determination of the recent trends in aerosol loading over the globe and then to focus specifically on the properties of aerosol over an urban site in southern India. Specific objectives are (a) to determine the trend in aerosol physical and optical properties over the globe using AERONET surface observations (b) to characterize the chemical properties of water soluble inorganic aerosol over an urban site in Southern India, Bangalore (c) to have a better estimation of aerosol radiative forcing over Bangalore with measured aerosol chemical concentration, black carbon concentration and aerosol optical depth (AOD). To quantify the recent trends in aerosol loading over the globe, we have used the surface observations from AERONET and the study provided the first step in giving a global picture of the recent trends in the fundamental optical and physical property of aerosol. Trend analysis showed a significant spatial inhomogenity, and Asian continent clearly showed an increasing trend in AOD compared to other continents. Solar village (24.9oN, 46.4oE) of Saudi Arabia showed a maximum with a value of 0.04/yr and Bac -Giang (21oN, 106oE) of Vietnam showed the minimum value of -0.04/yr. North American study region included 18 sites in which eastern US (E.US) exhibited a decreasing trend while the scenario in western US (W.US) is different with more of sites with increasing AOD trend. Single scattering albedo (SSA) trend in W. US showed a decreasing trend irrespective of the AOD trend. Study sites in South America include Cordoba -CETT (31.5oNS, 64.5 oN W) Alta Floresta (9.8oS, 56.1 o W), Riobranco (9.9oNS, 67.8o W) and Soa Poulo (23.5oS, 46.7o W).Except Riobranco which has a positive trend in AOD, all other sites exhibited a statistically signi cant negative trend. Over Australia, there is an inclination towards increasing AOD in sites and all the three sites in Australia exhibit a statistically significant increasing trend in SSA. According to the recent trends in AOD over African region, there exists a significant decrease in AOD compared to that reported for few years earlier, showing the high temporal in homogeneity and need for continuous observation of aerosol over the regions. European study region included 15 stations, among them only 3 sites showed an increasing trend in AOD, remaining 12 sites showed a significant decreasing trend in aerosol loading over the period of study. SSA was also observed to be decreasing over most of the European sites, even with a decreasing AOD over most of the sites. A Comparison study carried out to determine the relation of population growth rate and aerosol loading, and it revealed that the increasing AOD trend not always coincided with the sites having high population growth rate. Having determined the trends in AOD and other aerosol parameters over the globe and seeing an alarmingly increasing trend over most of the Asian sites, especially over Indian region, we have then focused over work on the aerosol properties of one of the rapidly growing urban location in southern India, Bangalore. While physical properties of aerosol have been extensively studied over Bangalore, chemical characteristics are still an unexplored area. Extensive information on aerosol chemical composition is not available over Indian region except for a few locations based on campaign mode. Even available data is of very coarse temporal resolution, since hours or full day sampling is needed to gather enough samples for chemical analysis. High temporal resolution data of aerosol chemical characteristics, especially for all season is completely lacking over Indian subcontinent. Among aerosol, water soluble aerosol form an important component in particulate matter, since it can change its size, composition, can easily mix with other aerosols and can act as cloud condensation nuclei, based on its hygroscopic nature. Present study provided the rst time results from a high temporal resolution water soluble inorganic aerosol chemical data over Indian region, which is first step towards estimating aerosol climate impacts more accurately. Water soluble inorganic aerosol ions over Bangalore namely, sulphate, nitrate, chloride, potassium, calcium, magnesium, sodium and ammonium are measured using Particle Into Liquid Sampler Ion Chromatograph (PILS-IC). PILS is an online sampling technique for quantitatively measuring the chemical concentration of ion in water soluble aerosol particles. PILS IC used in the present study is developed in Georgia Institute of Technology. Instrument samples ambient air at a flow rate of 16.7Lmin 1. Particles below PM 2.5 micron are collected for the analysis using cyclone impactor. Two annular glass denuders are used to remove inorganic gases which else will interfere with the aerosol ion concentration. Ambient air which is deprived of the inorganic gases is then mixed with steam vapours at 150oC, eventually high supersaturated atmosphere is produced with rapid adiabatic mixing of steam and ambient air. High supersaturated air allows droplets to grow enough to be collected by inertial impaction onto a quartz impactor plate. Entire PILS condensation unit is kept at a slight tilt of 15o, to remove all condensate through drain tube connected to the end of the PILS condensate body. Condensed liquid sample is collected from the impaction chamber and known concentration LiF is allowed to mix with the collected sample at a constant rate. LiF known as carrier liquid is added to know the dilution occurring to the collected sample. Sample with carrier liquid is then collected to a debubbler and is supplied to the IC through peristaltic tubings for determining the ion chemical concentration. Seasonal variation of mass concentration of water soluble aerosol species and the influence of long range transport is carried out using HYSPILT back trajectory analysis. Marine air mass from Arabian Sea dominated the air parcel reaching the site for both SW monsoon and summer. Continental air mass dominated the site during both NE monsoon and winter with slight contribution from marine atmosphere. Source characteristics of sulphate, potassium, calcium and magnesium ions are carried out based on sea salt (ss) and non sea salt (nss) origin and it is observed that the nss contribution is dominant over the site for all these ions except magnesium where ss component comparatively dominates the source. SO24 and NO3 form the dominant anions while NH+4 makes the dominant cation species. Monthly variation of the ratio of ammonium to nss -sulphate is carried out to determine the possible cation -anion relation existing between these two major ions. During later winter and summer months ammonium bi sulphate is found to be the existing chemical form and ammonium sulphate during other seasons. High temporal resolution data enabled us to study the diurnal variation of aerosol ions and it is influenced by various mechanisms from boundary layer to local emissions. Optical properties of aerosols depend upon the size and the relative abun-dance of each components. It is usual practice to assume default aerosol chemical composition in radiative transfer models due to unavailability of data, which can lead to errors in forcing estimates. Incorporating realistic aerosol chemical composition in models is essential to reduce the uncertainty in aerosol radiative forcing. Hence we have included measured aerosol chemical compositions, black carbon and AOD to improve the determination of radiative forcing of aerosol. OPAC and SBDART models were used for estimating the aerosol radiative forcing over Bangalore. We have used mainly four components namely, soot, water soluble, sea salt and dust. Except dust all are other components are measured over the site and formed a constrain for the calculation. Dust concentration was altered so that the OPAC AOD matched the measured AOD within 5%. Mineral dust shows the highest contribution in AOD among the four components, however water soluble and soot even being less is mass concentration compared to mineral dust, has significant impact on the AOD. This clearly indicate the influence of both water soluble and soot aerosol over the regional climate of the site. Sea Salt exhibited low AOD compared to other three constituents. The results presented in the thesis highlights the importance of varying trends in the aerosol properties and its effects on a global picture and speci - cally over an urban site in Indian region , we explored the temporal variations of water soluble inorganic aerosol ions and its effects on regional climate. Hence the thesis addressed some of the unexplored areas in aerosol science. This study also suggests the need of continuous observation of aerosol over both spatial and temporal scale, which is essential to estimate their effects on earth's climate.