Characteristic westerly sea breeze carries air over the Los Angeles Basin in Southern California to the Inland Empire approximately 50 miles inland, directly impacting air quality in both of these two highly polluted regions. As particles play a critical role in air quality and human health, this study compares the bulk aerosol profiles of the Los Angeles pollution "source" and Inland Empire "receptor" regions during the 2013 and 2014 NASA Student Airborne Research Program (SARP) campaigns onboard the NASA DC-8 airborne laboratory. The source and receptor regions were characterized by a series of missed approaches at the Los Angeles International Airport, Long Beach Airport, and Los Alamitos Army Airfield (coastal sources) as well as the Ontario International Airport, San Bernardino International Airport, and March Air Reserve Base (inland receptors). The aerosol populations in each region were compared, and the changes evolved were analyzed alongside volatile organic compound (VOC) concentrations from Whole Air Samples. Particle size distributions were collected using a Droplet Measurement Technologies Ultra High Sensitivity Aerosol Spectrometer (DMT-UHSAS). Aerosol concentration, mass, and mode diameter increased significantly between coastal pollution source and inland pollution receptor regions in all cases, along with an increase in mode diameter. The observed changes cannot be accounted for by aerosol aging over the Los Angeles basin alone, suggesting new particle emission/formation over this region could be a dominating factor in the changes. Positive correlations between particle increases at receptor sites and anthropogenic VOC tracers will be discussed.

An examination of the seasonal and spatial distribution of Polar Stratospheric Clouds (PSCs) inferred from standard temperature profiles in the lower-middle atmosphere above Antarctica, as derived from the Earth Observing System (EOS) Aura Microwave Limb Sounder (MLS) satellite observations and NCEP/NCAR assimilations, is provided. Chemical volume mixing ratio (VMR) observations of EOS Aura MLS v2.2 hydrogen chloride (HCl) were used to show the interannual variability of PSC formation with respect to stratospheric chlorine partitioning during five Southern Hemisphere Antarctic seasons from 2005 to 2009. A remarkable first set of results, obtained from an algorithm developed for modelling HCl depletion areas in the Antarctic polar vortex region, and based on satellite observations, is presented. In particular, the analysis of HCl concentration data obtained from 2006 indicated that the area processed for HCl was larger than the area of PSC during some periods of Antarctic winter, and that this result was robust with respect to the various PSC formation and HCl depletion thresholds utilized. The results suggest that an underestimation in chlorine activation area can occur when temperature thresholds for PSC formation thresholds are employed. The work presented here also evaluated chlorine activation via sulfate aerosol (SA) in the Southern Hemisphere 2006 stratosphere, based on satellite measurements of water vapor (H2O) and constant values of SA, by implementing the TACL formula of Drdla and Müller [2010] in contrast to the TNAT formula of Hanson and Mauersberger [1988]. The results indicated that the former formula was not completely sufficient for accurately modeling areas of depleted HCl and chlorine deactivation for all pressure surfaces in the Antarctic stratosphere. Based on the results of this study, the role of SA in chlorine activation appears to be more important at lower altitudes than for areas higher in the stratosphere.

Trace gases and aerosols, or suspended liquid and solid material in the atmosphere, have significant climatological and societal impacts; consequently, accurate representation of their contribution to atmospheric composition is vital to predicting climate change and informing policy actions. Sensitivity analysis allows scientists and environmental decision makers alike to ascertain the role a specific component of the very complex system that is the atmosphere of the Earth. Anthropogenic and natural emissions of gases and aerosol are transported by winds and interact with sunlight, allowing significant transformation before these species reach the end of their atmospheric life on land or in water. The adjoint-based sensitivity method assesses the relative importance of each emissions source to selected results of interest, including aerosol and cloud droplet concentration. In this work, the adjoint of a comprehensive inorganic aerosol thermodynamic equilibrium model was produced to improve the representativeness of regional and global chemical transport modeling. Furthermore, a global chemical transport model adjoint equipped with the adjoint of a cloud droplet activation parameterization was used to explore the footprint of emissions contributing to current and potential future cloud droplet concentrations, which impact the radiative balance of the earth. In future work, these sensitivity relationships can be exploited in optimization frameworks for assimilation of observations of the system, such as satellite-based or in situ measurements of aerosol or precursor trace gas concentrations.

The feedbacks among aerosols, clouds, and radiation are important components for understanding Earth's climate system and quantifying human-induced climate change, yet the magnitude of these feedbacks remain highly uncertain. Since every cloud droplet in the atmosphere begins with water condensing on a pre-existing aerosol particle, characterizing the ability of aerosols to uptake water vapor and form cloud condensation nuclei (CCN) are key to understanding the microphysics behind cloud formation, as well as assess the impact aerosols have on the Earth system. Through a combination of controlled laboratory experiments and field measurements, this thesis characterizes the ability of atmospheric aerosols to uptake water vapor and become CCN at controlled levels of water vapor supersaturation. The origin of the particle water uptake, termed hygroscopicity, is also explored, being from either the presence of deliquescent soluble material and/or adsorption onto insoluble surfaces. The data collected and presented is comprehensive and includes (1) ground samples of volcanic ash, collected from six recent eruptions re-suspended in the laboratory for analysis, (2) laboratory chamber and flow-tube studies on the oxidation and uptake of surface active organic compounds, and (3) in-situ aircraft measurements of aerosols from the Arctic background, Canadian boreal forests, fresh and aged biomass burning, anthropogenic industrial pollution, and from within tropical cyclones in the Atlantic basin. Having a more thorough understanding of aerosol water uptake will enable more accurate representation of cloud droplet number concentrations in global models, which can have important implications on reducing the uncertainty of aerosol-cloud-climate interactions, as well as additional uncertainties in aerosol transport, atmospheric lifetime, and impact on storm dynamics.

Geoengineering is the intentional alteration of the Earth’s climate system. The international Geoengineering Model Intercomparison Project (GeoMIP) seeks to identify the potential benefits and side effects of geoengineering on the Earth's climate. This thesis examines the first two experiments from the contribution of the Canadian Centre for Climate Modelling and Analysis to GeoMIP. In the first experiment (G1), atmospheric carbon dioxide concentrations are quadrupled and the solar constant is reduced to offset the increased greenhouse gas forcing. In the second experiment (G2), atmospheric carbon dioxide concentrations are increased at the rate of 1% per year and the solar constant is incrementally reduced to offset the greenhouse gas forcing. In concert with these experiments, results from two other experiments were analyzed, one in which the atmospheric greenhouse gas concentrations are quadrupled one in which they are increased at the rate of 1% per. The results obtained are in broad agreement with earlier work, showing that solar radiation management geoengineering schemes can prevent an increase in mean global surface temperature as atmospheric carbon dioxide concentrations increase. Though the mean global temperature remains constant while geoengineering is employed, there are regional and zonal differences from the control climate, with high latitude warming and cooling in the tropical and subtropical regions. In particular, the meridional temperature gradient is reduced compared to that of the control climate. The G2 experiment was very similar to the G1 experiment in terms of the spatial surface temperature changes, though the changes seen in the G2 experiment were less pronounced and the regions of statistical significance were smaller. During the geoengineering period, seasonal changes and a statistically significant decrease in global precipitation, particularly over the ocean were apparent in the G1 run. As with temperature, the spatial pattern of precipitation changes during the geoengineering period for G2 are similar to the same period in G1, but reduced in magnitude. However, most of the spatial changes to precipitation in the G2 experiment during geoengineering deployment fail to be statistically significant. Following geoengineering termination, the G1 experiment responds rapidly, with surface and ocean temperatures, NH and SH summer sea ice volume, AMOC transport volume and global precipitation following the same time evolution and reaching those same values found in the 4 × CO2 experiment’s first 10 years. Following geoengineering failure, the G2 run also experiences rapid climate change in all of the variables studied, but does not approach the first 10 years of the 1%CO2yr-1 experiment, because the forcings are quite different in the two runs. Taken together, these results suggest that, while geoengineering to reduce incoming solar radiation could offset the global temperature increase due to increased atmospheric greenhouse gas concentrations, there would be regional warming and cooling, as well as both global and regional impacts on the hydrological cycle. These results also suggest that, should geoengineering suddenly stop, the Earth’s climate would react immediately, with rapid changes in nearly all of the climate variables examined. / Graduate

The ocean emission and subsequent oxidation of dimethylsulfide (DMS) provides a source of sulfate in the atmosphere, potentially affecting the amount of solar radiation reaching the Earth's surface through both direct and indirect radiative effects of sulfate aerosols. DMS in the ocean can be quite variable with season and location, which in turn leads to high spatial and temporal variability of ocean DMS emissions. This study tested currently available observational and empirically-based climatologies of DMS concentration in the surface ocean. The exploration of the existing parameterizations mainly reveals the limitations of estimating DMS with an empirical model based on variables such as chlorophyll and mixed layer depth. The different algorithms show significant differences in spatial pattern, and none correlate strongly with observations. There is considerable uncertainty both in terms of the spatiotemporal distribution in DMS concentration and flux, as well as in the global total DMS flux. The present research investigates the influence of DMS on sulfate aerosols and radiative fluxes given different DMS climatologies in the fourth generation of the Canadian Global Atmospheric Climate Model (CanAM4.1). In general, the response in the radiative flux seems to follow the variation in the global mean flux of DMS linearly. Differences in the spatial and temporal structure of oceanic DMS have only a secondary effect on the radiative changes. The overall response of the atmosphere to the presence or absence of structure of DMS in space and time is distinctly smaller compared to the possible uncertainty of this response associated with the magnitude of the annually averaged global flux. / Graduate / 0425 / 0725 / 0416 / jetesdal@uvic.ca

Aerozolinė terapija, lėtine obstrukcine plaučių liga sergantiems arkliams, nėra labai dažnai taikomas gydymo būdas Lietuvoje, tačiau ši terapija yra plačiai taikoma kitose šalyse. Aerozolinė terapija yra efektyvus arklių lėtinės obstrukcinės plaučių ligos gydymo būdas. Darbo tikslas: Šio darbo tikslas yra nustatyti bronchus plečiančių preparatų, kaip salbutamolio ir gliukokortikoidų preparatų, kaip deksametazono, aerozolinės terapijos įtaką, lėtine obstrukcine plaučių liga sergančių arklių kraujo dujoms ir kraujo ląstelių morfologijai. Metodai: Tyrimui buvo atrinkti šeši arkliai, kurių amžius yra nuo 5 iki 18 metų. Visi arkliai buvo laikomi vienodomis sąlygomis. Arkliai buvo suskirstyti į dvi grupes: į pirmąją grupę buvo atrinkti trys arkliai (n=3), su klinikiniais lėtinės obstrukcinės plaučių ligos simptomais. Visiems pirmojoje grupėje esantiems arkliams anksčiau buvo diagnozuota lėtinė obstrukcinė plaučių liga. Į kontrolinę grupę buvo atrinkti trys sveiki arkliai (n=3), kuriems niekada nebuvo pasireiškusios kvėpavimo takų ligos. Aerozolinė terapija buvo taikoma vieną kartą per dieną, septynias dienas iš eilės. Pirmiausia buvo inhaliuojamas salbutamolis, o tada - deksametazonas. Kontrolinės grupės arkliai nebuvo gydomi. Kraujo tyrimai pirmosios grupės arkliams buvo imami prieš taikant aerozolinę terapiją ir po septynių dienų aerozolinės terapijos taikymo. Antrosios grupės arkliams kraujo tyrimai buvo imami vieną kartą. Kraujo dujų tyrimas buvo atliekamas iš karto po... [toliau žr. visą tekstą] / Equine aerosol therapy for treating recurrent airway disease in horses is not a very common therapy used in Lithuania, but it is widely used in other countries. It is a very effective way of treating horses in crisis with reccurent airway disease. Aim of the study: The aim of this study was to establish, how the results of blood gas and blood cell morphology change after an aerosol bronchodilator such as salbutamol and the use of glucocorticoid such as dexamethazone for therapy on horses with recurrent airway disease. Methods: There were six horses in this study, 5 - 18 years of age, and they were kept under the same conditions. The horses were divided into two groups: the first group was made up of three horses (n = 3), previously diagnosed with recurrent airway disease. At the time of the study they had clinical signs of the disease. The control group were also made up of three horses (n = 3), who have never been diagnosed with respiratory diseases. Horses from the first group, were treated with aerosol salbutamol and dexamethasone for a week, once a day, with an ultrasound nebulizer. Horses from the control group were not treated. Blood samples from the horses of the first group were taken before aerosol therapy and after a one week period of therapy blood samples were drawn again for comparison. Blood samples from the control group were taken once. Blood gas tests were carried out with an Epoc blood analyzer and blood cell morphology was carried out with Abacus... [to full text]

The modeling results of current global aerosol models agree, generally within a factor of two, with the measured surface concentrations of black carbon (BC) and sulphate (SF) aerosols in rural areas across the northern continents. However, few models are able to capture the observed seasonal cycle of the Arctic aerosols. In general, the observed seasonality of the Arctic aerosols is determined by complex processes, including transport, emissions and removal processes. In this work, the representations of aerosol deposition processes (i.e., dry deposition, in-cloud and below-cloud scavenging) within the framework of the Canadian Global Air Quality Model – GEM-AQ are first enhanced. Through the enhancements in GEM-AQ, the seasonality of the Arctic BC and SF is reproduced, and the improvement in model performance extends to the rest of the globe as well. Then, the importance of these deposition processes in governing the Arctic BC and SF seasonality is investigated. It is found that the observed seasonality of the Arctic BC and SF is mainly caused by the seasonal changes in aerosol wet scavenging, as well as the seasonal injection of aerosols from surrounding source regions. Being able to reproduce the seasonality of the Arctic BC, the enhanced GEM-AQ allows more accurate assessment of the contributions of anthropogenic sources to the BC abundance in the Arctic air and deposition to the Arctic surface. Simulating results on regional contributions to the Arctic BC show a strong dependence on altitude. The results reinforce the previous finding of Eurasia being the dominant contributor to the surface BC in the Arctic, and suggest a significant contribution from Asian Russia. In addition to the seasonality of the Arctic aerosols, the inter-annual variation in the Arctic BC surface concentration is also investigated. To complement the 3-D GEM-AQ model, the atmospheric backward trajectory analysis, together with estimated BC emissions, is implemented as a computational effective approach to reconstruct BC surface concentrations observed at the Canadian high Arctic station, Alert. Strong correlations are found between the reconstructed and the measured BC in the cold season at Alert between 1990 and 2005, which implies that atmospheric transport and emissions are the major contributors to the observed inter-annual variations and trends in BC. The regional contributions estimated annually from 1990 through 2005 suggest that Eurasia is the major contributor in winter and spring to the near-surface BC level at Alert with a 16-year average contribution of over 85% (specifically 94% in winter and 70% in spring). A decreasing trend in the Eurasian contribution to the Arctic is found in this study, which is mainly due to regional emission reduction. However, the inter-annual variation in the North American contribution shows no clear trend.

La finalitat d'aquest treball ha estat l'estudi i caracterització dels components inorgànics de l'aerosol en una àrea urbana que ha estat la de Sant Adrià de Besòs.Hom ha procedit a posar a punt un mètode analític per cromatografia liquida de bescanvi iònic per tal de poder determinar els anions inorgànics presents a l'atmosfera.Aquest mètode utilitza només una columna separadora de bescanvi iònic i detector ultraviolat, i permet determinar simultàniament els anions clorur, bromur nitrito i nitrat per fotometria directa, i clorur, nitrat i sulfat per fotometria indirecta, i arribar a límits de detecció entre 1 i 5 ppb, excepte per al sulfat, que té un límit de detecció de 100 ppb. El desenvolupament del mètode analític conté la comparació entre diverses columnes, diversos eluents i diferents tipus de detecció ultraviolada i l'estudi de la linealitat, la desviació estàndard i la sensibilitat del mètode. Aquest mètode permet determinar els anions majoritaris i minoritaris de l'aerosol utilitzant els dos tipus de fotometria directa i indirecta, ja que ambdós mètodes són perfectament compatibles.Un cop optimitzat el mètode analític per a la determinación dels anions inorgànics, s'ha palesat la possibilitat de determinar els metalls per espectroscòpia d'emissió per plasma. Com que aquest mètode és prou conegut per a la determinació de metalls, només s'ha comprovat la no existència d'interferències i la linealitat de les rectes dins del rang de concentració en què es troben els metalls a l'atmosfera. Els metalls analitzats han estat: Zn, Pb, Ni, Mn, Fe, V, Ca i Al. Aquests metalls són elements traçadors de fonts emissores contaminants. El mètode permet arribar a límits de detecció entre 1 i 10 ppb, la qual cosa fa que sigui una tècnica adequada per a aquest tipus d'estudi.Seguidament hom ha procedit a la comparació de diferents tipus de filtres i captadors per optimitzar la presa de mostres tenint en compte les espècies que cal estudiar. El mètode de captació utilitzat ha estat amb captadors d'alt volum Sierra Misco i filtres de membrana Millipore de 20 x 25 cm.L'etapa següent ha estat l'extracció de les partícules del filtre comparant-la amb mètodes estàndard. El procediment més adequat per a l'extracció de metalls de les partícules dels filtres resulta ser la digestió àcida amb àcid clorhídric i nítric durant dues hores. Per a l'extracció dels anions hom ha utilitzat aigua en ebullició durant mitja hora. La recuperació de les espècies presents en forma de partícules ve reforçada per l'homogeneïtat trobada al filtre.Hom ha realitzat l'anàlisi de partícules atmosfèriques a Sant Adrià de Besòs durant vuit setmanes, repartides en les quatre estacions de l'any.Un cop obtingudes les matrius de dades per a les vuit setmanes, s'ha aplicat l'anàlisi factorial com a model de receptor per a l'anàlisi quimiomètrica dels resultats de les mostres de Sant Adrià de Besòs durant el període de juny de 1986 a abril de 1987. Això s'ha fet per tal de conèixer les fonts contaminants i els percentatges de col·laboració de cada una de les fonts. Hem trobat sis fonts contaminants emissores: el sòl, el tràfic, el nitrat i el sulfat, el gas-oil, l'aerosol marí i les emissions d'aceries o d'incineradors.Com que un dels problemes més importants en la captació d'anions inorgànics és la formació d'artefactes, s'han comparat dos tipus de presa de mostres, amb i sense separació prèvia dels gasos presents a l'atmosfera.Aquest estudi ha estat realitzat al Departament de Química Inorgànica de la Universitat de Dortmund, ja que aquí no era possible d'aconseguir l'equip adient. Hem constatat diferències en els valors obtinguts durant la captació de clorurs i nitrats causats per la formació d'artefactes, pèrdues per volatilitat o col·lapsament del filtre. S'ha comprovat que la tècnica dels separadors de gasos o "denuders" permet assegurar valors fiables per al contingut d'aquests dos anions a les partícules. El contingut de sulfats no presentava diferències amb el mètode de captación sense "denuders" amb filtres Nucleopore. S'ha verificat també la formació d'artefactes de sulfit.Finalment s'ha aplicat el mètode optimitzat de l'anàlisi dels anions inorgànics a la deteminació d'anions separats en un impactador en cascada de baix volum, el qual necessita d'una anàlisi molt sensible per als components minoritaris de l'aerosol. Aquesta presa de mostres amb impactador en cascada també ha estat realitzada a Dortmund. Hom ha verificat que els anions bromur, nitrat I sulfat es troben principalment a la fracció més fina de l'aerosol mentre que el clorur presenta diferències. / The purpose of this work is to study and characterize the inorganic components of the aerosols in a built-up urban area that of Sant Adrià de Besòs.Determination of the inorganic anions chloride, bromide, nitrate and sulphate was undertaken by using the ion exchange liquid chromatography technique, which was optimized .in our laboratory. The detection method used was that of the ultraviolet, using bath direct and indirect photometry.Determination of the metals Zn, Pb, Ni, Mn, Fe, V, Ca and Al was carried out with inductively coupled plasma.We optimized the sampling technique by varying different kinds of filters and samplers. We also optimized the extraction of anions and metals from the particles in the filters.The next step was to analyse the atmospheric particles in Sant Adrià de Besòs over a period of eight weeks. The data obtained was treated by using factor analysis in order to ascertain pollutant sources, which were: soil (Mn, Ca, Al and Fe), traffic (Pb and Br), gases (nitrate and sulphate), fuel oil (Ni and V), marine aerosol (CI) and emissions from incinerator plants or steelworks (Zn).We have compared sampling methods with and without prior separation of gases present in the atmosphere in order to ascertain the variations that the particles undergo during their sampling.The optimization of the analytical method for determining inorganic anions has been applied to the determination of these anions in particles sampled in a cascade impactor.

Marine aerosols have attracted increasing attention over the past 15 years because of their potential significance for global climate modelling. The size distribution of these aerosols extends from super-micrometer sea salt mode particles down through 150 nm accumulation mode particles, 40 nm Aitken mode particles and nucleation mode particles which extend from 25 nm right down to clusters of a few molecules. The process by which the submicrometer modes form and grow and their composition have remained topics of debate throughout this time in large part because of the difficulties associated with determining their composition and relating it to proposed models of the formation process. The work compared the modality of marine aerosol influencing the South-east-Queensland region with that of other environmental aerosols in the region. The aerosol was found to be consistent with marine aerosols observed elsewhere with concentrations below 1000 cm-3 and frequently exhibiting the distinct bimodal structure associated with cloud processing, consisting of an Aitken mode at approximately 40 nm, an accumulation mode in the range 100-200 nm and a coarse mode attributed to sea salt between 600 and 1200 nm. This work included the development of two new techniques for aerosol research. The first technique measures aerosol density using a combination of aerosol size distribution and gravimetric mass concentration measurements. This technique was used to measure the density of a number of submicrometer aerosols including laboratory generated NaCl aerosol and ambient aerosol. The densities for the laboratory generated aerosols were found to be similar to those for the bulk materials used to produce them. The technique, extended to super-micrometer particle size range may find application in ambient aerosol research where it could be used to discriminate between periods when the aerosol is dominated by NaCl and periods when the density is more representative of crustal material or sulfates. The technique may also prove useful in laboratory or industrial settings for investigating particle density or in case where the composition is known, morphology and porosity. The second technique developed, integrates the existing physicochemical techniques of volatilisation and hygroscopic growth analysis to investigate particle composition in terms of both the volatilisation temperatures of the chemical constituents and their contribution to particle hygroscopic behaviour. The resulting volatilisation and humidification tandem differential mobility analyser or VH-TDMA, has proven to be a valuable research tool which is being used in ongoing research. Findings of investigations relating the composition of the submicrometer marine aerosol modes to candidate models for their formation are presented. Sea salt was not found in the numerically dominant particle type in coastal nucleation mode or marine Aitken and accumulation modes examined on the Southeast Queensland coast during periods where back trajectories indicated marine origin. The work suggests that all three submicrometer modes contain the same four volatile chemical species and an insoluble non-volatile residue. The volatility and hygroscopic behaviours of the particles are consistent with a composition consisting of a core composed of sulfuric acid, ammonium sulfate and an iodine oxide coated with a volatile organic compound. The volume fraction of the sulfuric acid like species in the particles shows a strong dependence on particle size.