An Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) was used to obtain mass spectra of individual aerosol particles in the 0.5 – 2 µm size range in downtown Toronto, Canada for one to two month periods during each season of 2007. A modified version of the Adaptive Resonance Theory (ART-2a) clustering algorithm, which clusters particles based on the similarity of their mass spectra, was shown to be more accurate than the existing algorithm and was used to cluster the ambient data. A total of 21 unique particle types were identified and were characterized based on their chemical composition, their size, and their temporal trends and seasonal variations. Potential sources are also discussed. Particles containing trimethylamine (TMA) were also observed and a more detailed investigation of ambient trends in conjunction with a laboratory experiment was performed in order to elucidate conditions for which TMA will be observed in the particle phase in Southern Ontario.

An Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) was used to obtain mass spectra of individual aerosol particles in the 0.5 – 2 µm size range in downtown Toronto, Canada for one to two month periods during each season of 2007. A modified version of the Adaptive Resonance Theory (ART-2a) clustering algorithm, which clusters particles based on the similarity of their mass spectra, was shown to be more accurate than the existing algorithm and was used to cluster the ambient data. A total of 21 unique particle types were identified and were characterized based on their chemical composition, their size, and their temporal trends and seasonal variations. Potential sources are also discussed. Particles containing trimethylamine (TMA) were also observed and a more detailed investigation of ambient trends in conjunction with a laboratory experiment was performed in order to elucidate conditions for which TMA will be observed in the particle phase in Southern Ontario.

La poussière minérale est l'aérosol le plus abondant injecté dans l'atmosphère. Les surfaces de poussière peuvent être le siège de phénomènes d‘adsorption et de transformation hétérogène de gaz traces et peuvent affecter la teneur en espèces clés atmosphériques. Dans ce contexte, l'objectif de ce travail était l'étude expérimentale de la réactivité de particules minérales avec des gaz traces atmosphériques. L'interaction de réactifs gazeux (NO2, HONO, H2O2, OH, HO2) avec des oxydes minéraux (TiO2, Al2O3, Fe2O3, Arizona Test Dust) a été étudiée à l'aide d'un photoréacteur mis en place dans le cadre de la thèse pour des études de processus hétérogènes photochimiques. Le photoréacteur consiste en un tube à écoulement (irradié par 6 lampes UV) à basse pression (quelques Torr), couplé à l‘analyse des espèces par un spectromètre de masse quadripolaire à ionisation par impact électronique. Les coefficients de capture (ou probabilité de perte d'une espèce gazeuse par collision avec la surface réactive) ainsi que les produits de réactions hétérogènes ont été déterminés en fonction de différents paramètres tels que la masse du film minéral, la concentration initiale du réactif gazeux, la température, l‘humidité relative, la concentration d'oxygène et l'intensité d'irradiation UV. Les mécanismes des processus hétérogènes étudiés et leurs implications atmosphériques ont été discutés. En particulier, les données obtenues indiquent que la contribution de l'aérosol à la perte totale de HONO dans la couche limite planétaire est négligeable. A l‘inverse, l'interaction de H2O2 et des radicaux HO2 avec des aérosols minéraux peut être un puits non négligeable d'espèces HOx (OH, HO2) dans la troposphère avec un effet sur le pouvoir oxydant de la troposphère. / Mineral dust is the most abundant aerosol injected into the atmosphere. The dust surfaces provide the seedbed for adsorption and heterogeneous transformation of trace gas molecules and can affect the content of key atmospheric species. In this context, the goal of the present work was the experimental investigation of the reactivity of mineral dust particles toward trace atmospheric gases. The interaction of gaseous reactants (NO2, HONO, H2O2, OH, HO2) with mineral oxides (TiO2, Al2O3, Fe2O3, Arizona Test Dust) was studied using a photoreactor developed during this work for studies of heterogeneous photochemical processes. The photoreactor comprises a low pressure (several Torr) flow reactor (irradiated with 6 UV lamps) combined with an electron impact ionization quadrupole mass spectrometer for analysis of gas phase species. The uptake coefficients (determined as the probability of gas species loss per collision with reactive surface) as well as the products of heterogeneous reactions were determined as a function of different parameters such as the mass of mineral film, initial concentration of the gaseous reactant, temperature, relative humidity, concentration of oxygen and UV irradiation intensity. The mechanisms of the heterogeneous processes studied and their atmospheric implications are discussed. In particular, the data obtained in the present work indicate that the contribution of the aerosol to the total loss of HONO in the planetary boundary layer is negligible. Instead, the interaction of H2O2 and of HO2 radicals with mineral aerosols may be an important sink for HOX (OH, HO2) species in the troposphere with an effect on the oxidative capacity of the troposphere.

Phenomenon of industrial grounds placed near residential areas can be frequently detected in European cities, which may cause decrease of air quality in these areas. The aim of this diploma thesis is to determine level of concentration and size distribution of aerosol in the planetary boundary layer above the residential area and industrial complex of Škoda auto a.s. in Mladá Boleslav city by using remotely controlled airship. Thereby, the thesis extends terrestrial experiment realized in February and March 2013 which revealed no significant impact of industry and traffic on air quality. Size distribution and concentration of aerosol particles in range from 11.5nm to 10µm with integration time one second or one minute (depending on measure mode - SINGLE or SCAN) was measured by two aerosol spectrometers placed in dirigible gondola during 13 flights on February 11, 2015. SINGLE mode lead the airship in one stable flight level during one flight above residential area and industrial complex of Škoda auto a.s. Whereas SCAN mode changed flight level every two minutes during the flight of airship above sports fields in residential zone only. Exhausts of car painting halls and place of automobile loading were identified as the sources of nanoparticles, PM1 a PM2.5 and coarse aerosol in the industrial area...

Title: What is the connection between atmospheric aerosols, meteorological pa- rameters and gaseous pollutants? Author: RNDr. Naděžda Slezáčková Zíková Department: Department of Meteorology and Environment Protection Supervisor: Ing. Vladimír Ždímal, Dr. Laboratory of Aerosol Chemistry and Physics, Institute of Chemical Process Fun- damentals, Czech Academy of Sciences, v.v.i. Abstract: Five years of atmospheric aerosol (AA) measurements at rural back- ground station Košetice were compared with meteorological records and gaseous pollutants concentrations. The sampling and data analysis of AA data is de- scribed, and the statistical evaluation is done. The variability in the AA con- centrations is significant; the long-term measurements of AA, over the period at least several years, and the differentiation according to the season of the year are thus necessary. The clearly expressed annual cycle of AA concentrations is mainly influenced by two phenomena. From April to September, the total AA concentration cycle is driven mainly by the new particles formation events, from October to March, the concentrations are strongly influenced by particles coming from long-range transport and/or from the regional pollution. The relationship between AA and meteorological parameters, however, is not only season...

Diploma thesis deals with the analysis of saccharides and markers of biomass and wood combustion in atmospheric aerosol, PM2,5. Theoretic part is focused on general characterisation of atmospheric aerosols and on the properties, sources and analysis methods of selected analysed organic compounds. The experimental part is focused on the optimization of method for simultaneous analysis of saccharides and tracers from biomass and wood combustion. Optimization of method includes selection of solvent for the extraction of compounds and optimization of derivatization process and GC/MS analysis. The optimized method was then applied for the analysis of selected compounds in real aerosol samples in the size fraction PM2.5. The concentrations of analysed compounds were compared in term of sampling seasons.

Title: Formation and transformation of atmospheric aerosol in boundary layer Author: Mgr. Adéla Holubová Šmejkalová Institute: Institute for Environmental Studies Supervisor: Ing. Vladimír Ždímal, Dr., Institute of Chemical Process Fundamen- tals of the CAS Training workplace: Institute of Chemical Process Fundamentals of the CAS Abstract: The experimental measurement of aerosol clusters from 1.17 nm in size was carried out from August 2016 till December 2018 at the National Atmospheric Observatory Košetice. Atmospheric conditions leading to aerosol clusters stabili- zation, fresh particles formation and particle growth were analyzed. Data of days with no new particle formation confrmed the connection between mixing layer height development and decrease of total aerosol number concentration together with lower gaseous pollutant concentrations. On the contrary, new particle for- mation process overcomes dilution of the atmosphere by increasing the number of freshly nucleated particles. Only decreasing gaseous pollutant concentrations were observed during these events. The atmospheric boundary layer was high du- ring new particle formation events that can mean enrichment of the atmosphere by other components transported by long-range transport or some transfer from the free troposphere. The measurement in...

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Atmospheric fine particulate matter (PM2.5), which is mostly formed in the atmosphere from precursor gases, contributes to numerous environmental and health concerns. Quantifying the ambient concentrations of PM2.5 and precursor gases can be challenging. Hence, many scientific questions about the formation, chemical composition, and gas/particle partitioning of PM2.5 remain unanswered. Ambient Ion Monitor - Ion Chromatography (AIM-IC) was characterized and utilized to measure the water-soluble composition of PM2.5 (dominated by pNH4+, pSO42-, and pNO3-) and associated precursor gases (dominated by NH3(g), SO2(g), and HNO3(g)) during two field campaigns. The AIM-IC detection limits for hourly sampling were determined to be 3 - 45 ng m-3. The response time for “sticky” gases was significantly improved with a nylon denuder membrane. A novel inlet configuration for the AIM-IC, which minimizes sampling inlet losses and carryover in sample analyses, was implemented. Measurements from the BAQS-Met 2007 campaign were utilized to assess the accuracy of the AURAMS model and investigate gas/particle partitioning in SW Ontario. Due to high sulphate levels, NH3(g) was the limiting chemical factor in the formation and gas/particle partitioning of PM2.5. The errors in the predictions of relative humidity and free ammonia were responsible for the poor agreement iii between modelled and measured pNO3- values. The AIM-IC measurements from the CalNex 2010 study were compared to the CMAQ model and utilized to investigate the gas/particle partitioning in Bakersfield, CA. Very high NH3(g) concentrations were observed, and the formation and partitioning of PM2.5 was limited by HNO3(g) and H2SO4. Evidence of rapid removal of HNO3(g) by interactions with super-micron dust particles, and possibly with the alkaline surface was found. CMAQ exhibited significant biases in the predicted concentrations of pSO42-, NH3(g) and HNO3(g).

Atmospheric fine particulate matter (PM2.5), which is mostly formed in the atmosphere from precursor gases, contributes to numerous environmental and health concerns. Quantifying the ambient concentrations of PM2.5 and precursor gases can be challenging. Hence, many scientific questions about the formation, chemical composition, and gas/particle partitioning of PM2.5 remain unanswered. Ambient Ion Monitor - Ion Chromatography (AIM-IC) was characterized and utilized to measure the water-soluble composition of PM2.5 (dominated by pNH4+, pSO42-, and pNO3-) and associated precursor gases (dominated by NH3(g), SO2(g), and HNO3(g)) during two field campaigns. The AIM-IC detection limits for hourly sampling were determined to be 3 - 45 ng m-3. The response time for “sticky” gases was significantly improved with a nylon denuder membrane. A novel inlet configuration for the AIM-IC, which minimizes sampling inlet losses and carryover in sample analyses, was implemented. Measurements from the BAQS-Met 2007 campaign were utilized to assess the accuracy of the AURAMS model and investigate gas/particle partitioning in SW Ontario. Due to high sulphate levels, NH3(g) was the limiting chemical factor in the formation and gas/particle partitioning of PM2.5. The errors in the predictions of relative humidity and free ammonia were responsible for the poor agreement iii between modelled and measured pNO3- values. The AIM-IC measurements from the CalNex 2010 study were compared to the CMAQ model and utilized to investigate the gas/particle partitioning in Bakersfield, CA. Very high NH3(g) concentrations were observed, and the formation and partitioning of PM2.5 was limited by HNO3(g) and H2SO4. Evidence of rapid removal of HNO3(g) by interactions with super-micron dust particles, and possibly with the alkaline surface was found. CMAQ exhibited significant biases in the predicted concentrations of pSO42-, NH3(g) and HNO3(g).