Urban air pollution is responsible for high levels of morbidity and mortality in exposed populations due to its effects on cardiovascular and respiratory function. Transportation-related air pollutants account for the majority of harmful air pollution in urban areas. Forests are known to reduce air pollution through their ability to facilitate dry deposition and atmospheric gas exchange. This work characterizes the interactions between transportation air pollutants and urban forests in Hillsborough County, Florida. A highly spatially resolved passive air sampling campaign was conducted to characterize local concentrations of nitrogen oxides, benzene, toluene, ethylbenzene, and xylenes (BTEX) in Hillsborough County, Florida. Sampling locations included a proportion of densely forested urban areas in order to determine the effects of Hillsborough County's urban forest resources on localized concentrations of selected transportation pollutants. Recommended approaches for the use of urban forests as an effective air pollution mitigation technique in Hillsborough County were generated based on results from the sampling campaign. Results show mean concentrations of 2.1 parts per billion and 6.5 µg/m3 for nitrogen oxides and total BTEX, respectively. High spatial variability in pollutant concentrations across Hillsborough County was observed, with the coefficient of variation found to be 0.61 for nitrogen oxides and 0.79 for total BTEX. Higher concentrations were observed along interstate highways, in urban areas of the county, and near select point sources in rural areas. Differences in concentrations within forested areas were observed, but were not statistically significant at the 95%#37; confidence level. These results can be used to identify elements of urban design which contribute to differences in concentrations and exposures. This information can be used to create more sustainable urban designs which promote health and equity of the population.

Land surface areas, which represent approximately 30% of the Earth’s surface, contribute largely to the complexity of the climate system by exchanging water, energy, momentum, and chemical materials with the overlying atmosphere. Because of the highly heterogeneous nature of the land surface and its rapid transformation due to human activities, future climate projections are less certain on regional scales than for the globe as a whole. The work presented in this dissertation is focused on a better understanding of regional-scale land–atmosphere interactions and their impacts on climate and air quality. Specifically, I concentrate my research on three typical regions in the United States (U.S.): 1) the Central U.S. (representing transition zones between arid and wet climates); 2) the Houston metropolitan region (representing a major urban area); and 3) the eastern U.S. (representing temperate forested regions). These regions are also chosen owing to the consideration of data availability. The first study concerns the roles of vegetation phenology and groundwater dynamics in regulating evapotranspiration and precipitation over the transition zones in summer months. It is found that the warm-season precipitation in the Central U.S. is sensitive to latent heat fluxes controlled by vegetation dynamics. Groundwater enhances the persistence of soil moisture memory from rainy periods to dry periods by transferring water to upper soil layers through capillary forces. Enhancement in soil moisture facilitates vegetation persistence in dry periods, producing more evaporation to the atmosphere and resulting in enhanced precipitation, which then increases soil moisture. The second study compares the impacts of future urbanization and climate change on regional air quality. The results show that the effect of land use change on surface ozone (O3) is comparable to that of climate change, but the details differ across the domain. The third study deals with the formation and distributions of secondary organic aerosols (SOA) — a largely overlooked but potentially important component in the climate system. Under future different climate scenarios, I found that biogenic emissions — an important precursor of SOA — are expected to increase everywhere over the U.S., with the largest increase found in the southeastern U.S. and the northwestern U.S., while changes in SOA do not necessarily follow those in biogenic emissions. Other factors such as partitioning coefficients, atmospheric oxidative capability, primary organic carbon, and anthropogenic emissions also play a role in SOA formation. Direct and indirect impacts from climate change complicate the future SOA formation. / text

Submitted by Valquíria Barbieri (kikibarbi@hotmail.com) on 2018-04-12T21:14:58Z No. of bitstreams: 1 DISS_2014_Anna Carolinna Albino Santos.pdf: 2580158 bytes, checksum: 7c462cc6d9578f7ac6db50c5de436a44 (MD5) / Approved for entry into archive by Jordan (jordanbiblio@gmail.com) on 2018-04-27T14:47:45Z (GMT) No. of bitstreams: 1 DISS_2014_Anna Carolinna Albino Santos.pdf: 2580158 bytes, checksum: 7c462cc6d9578f7ac6db50c5de436a44 (MD5) / Made available in DSpace on 2018-04-27T14:47:45Z (GMT). No. of bitstreams: 1 DISS_2014_Anna Carolinna Albino Santos.pdf: 2580158 bytes, checksum: 7c462cc6d9578f7ac6db50c5de436a44 (MD5) Previous issue date: 2014-02-17 / CAPES / O Pantanal constitui em uma região de enorme importância ecológica e socioeconômica. A região pantaneira é a maior área alagável contínua existente e tem-se apresentando interesse nos estudos relacionados ao clima para entender os mecanismos antrópicos e naturais que são capazes de regular a composição da atmosfera. Pode-se avaliar o impacto das queimadas e, sobretudo, determinar a variabilidade sazonal da concentração de aerossóis nessa região. O objetivo desse trabalho foi caracterizar a composição elementar de aerossóis, a variabilidade sazonal da concentração de material particulado, e avaliar as fontes de material particulado no Pantanal Mato-Grossense. As amostras de aerossóis atmosféricos foram coletadas de abril de 2012 a agosto de 2013 na Baía das Pedras, localizada no Pantanal Matogrossense, Brasil. O dispositivo de amostragem consistiu em amostradores de particulado fino e grosso (AFG), que separam a fração fina do aerossol (dp˂ 2,5 μm) e a fração grossa (2,5 – 10 μm). A análise de composição elementar foi realizada com Fluorescência de Raios-X por energia dispersiva. Três tipos de fontes de aerossóis foram estimadas através do PMF (Positive Matrix Factorization): emissões biogênicas naturais, ressuspensão de poeira do solo e queima da biomassa. Na estação seca observou-se uma média de 0,00866 μg/m3 para o material particulado fino e 0,00721 μg/m3 para o material particulado grosso. A fração conhecida do MPF representou 20,8 % de sua massa na estação seca, sendo a do MPG representou 20,1 %. Na estação chuvosa observou-se uma média de 0,00424 μg/m3 para MPF e 0,00544 μg/m3 para MPG. A fração conhecida do MPF representou 24,5 % e MPG, 23,8 %. / The Pantanal is a region of enormous ecological and socioeconomic importance. The Pantanal is the largest wetland existing continuous and has been showing interest in climate-related studies to understand the anthropogenic and natural mechanisms that are able to regulate the composition of the atmosphere. Can assess the impact of fires and especially to determine the seasonal variability of aerosol concentration in this region. The purpose of this study was to characterize the aerosol elemental composition, the seasonal variability of concentrations, and to evaluate the sources of particulate matter in the Pantanal Mato Grossense. Atmospheric aerosol samples were collected from April 2012 to August 2013 at Baía das Pedras, located in Pantanal, Brazil. The sampling device consisted of particulate samplers (SFU – stacked filter units), which separates the fine fraction ( dp ˂ 2.5 μm ) and the coarse fraction ( 2,5 - 10 μm ) of the aerosols. The elemental analysis was done using X- ray fluorescence by dispersive energy. Three types of aerosol sources were determined for both seasons by PMF (Positive Matrix Factorization) analysis: natural biogenic emissions, resuspension of soil dust, and biomass burning, being sources of fine and coarse particles. In the dry season there was an average of 0.00866 μg/m3 for fine particulate matter and 0.00721 μg/m3 for coarse particulate matter. A known fraction of MPF represented 20.8 % of its mass in the dry season, with an MPG represented 20.1 %. In the rainy season there was an average of 0.00424 μg/m3 for MPF and 0.00544 μg/m3 for MPG. A known fraction of MPF represented 24.5% and MPG, 23.8%.

There is an urgency within the building sector to reduce its greenhouse gas emissions and mitigate climate change. An increased proportion of biobased building materials in construction is a potential measure to reduce these emissions. Life cycle assessment (LCA) has often been applied to compare the climate impact from biobased materials with that from e.g. mineral based materials, mostly favouring biobased materials. Contradicting results have however been reported due to differences in methodology, as there is not yet consensus regarding certain aspects. The aim of this thesis is to study the implications from non-traditional practices in climate impact assessment of timber buildings, and to discuss the shortcomings of current practices when assessing such products and comparing them with non-renewable alternatives. The traditional practices for climate impact assessment of biobased materials have been identified, and then applied to a case study of a building with different timber frame designs and an alternative building with a concrete frame. Then, non-traditional practices were explored by calculating climate impact results using alternative methods to handle certain methodological aspects, which have been found relevant for forest products in previous research such as the timing of emissions, biogenic emissions, carbon storage in the products, end-of-life substitution credits, soil carbon disturbances and change in albedo. These alternative practices and their implications were also studied for low-carbon buildings. The use of non-traditional practices can affect the climate impact assessment results of timber buildings, and to some extent the comparison with buildings with lower content of biobased building materials. This effect is especially evident for energy-efficient buildings. Current normal practices tend to account separately for forest-related carbon flows and aspects such as biogenic carbon emissions and sequestration or effects from carbon storage in the products, missing to capture the forest carbon cycle as a whole. Climate neutrality of wood-based construction materials seems like a valid assumption for studies which require methodological simplification, while other aspects such as end-of-life substitution credits, soil carbon disturbances or changes in albedo should be studied carefully due to their potentially high implications and the uncertainties around the methods used to account for them. If forest phenomena are to be included in LCA studies, a robust and complete model of the forest carbon cycle should be used. Another shortcoming is the lack of clear communication of the way some important aspects were handled. / <p>QC 20150310</p>

A técnica de confinamento de folhas de plantas em câmara de Teflon rígido (cuvette), com visor em vidro, submetida a um fluxo contínuo de ar foi adotada na avaliação da emissão de compostos carbonílicos voláteis por plantas. Os carbonílicos foram coletados sobre sílica impregnada com o reagente derivatizante 2,4-dinitrofenilhidrazina e analisados por cromatografia a líquido de alto desempenho e detecção por ultravioleta. Foram identificados e quantificados aldeídos alifáticos saturados (C1 a C6) e insaturados (acroleína, metacroleína, crotonaldeído), benzaldeído, acetona e 2-butanona. A temperatura ambiente e na superfície das folhas, a umidade relativa do ar, a intensidade da luz solar e os níveis de ozônio e de óxidos de nitrogênio no ar foram monitorados durante as coletas de amostras. Com o objetivo de avaliar os níveis de fundo de carbonílicos no sistema coletor empregado, 29 amostras de ar foram coletadas sem a introdução de folhas de planta no cuvette, em condições ambientais de laboratório e campo. Uma avaliação estatística dos resultados indicou que os níveis de fundo do cuvette vazio foram próximos a zero nas coletas feitas no laboratório e aumentaram de acordo com o aumento da intensidade da luz solar nas coletas em campo. Esses resultados mostraram que a exposição do cuvette à radiação solar conduz à formação de artefato positivo de amostragem. Foram feitas medidas da emissão de carbonílicos pela espécie Ficus benjamina, para a qual foram observadas taxas de emissão de acetaldeído altas em condições de temperatura na superfície das folhas superior a 40°C. Na ausência de luz solar incidente, não foi observada emissão de carbonílicos pelo exemplar avaliado dessa espécie. Foram feitas também medidas da emissão de carbonílicos pelas seguintes espécies de plantas ocorrentes na vegetação nativa da Região Metropolitana de São Paulo: Cecropia pachystachya, Casearia sylvestris, Croton floribundus, Solanum erianthum, Alchornea sidifolia, Syagrus rommanzoffiana e Ficus insipida, para as quais foram observadas taxas de emissão de carbonílicos que variaram entre 1,5 10-2 e 2,3 &#181;gC g-1 h-1. / The leaf enclosure technique in air flow-through rigid Teflon chamber (cuvette) was employed to evaluate volatile carbonyl compound emission from plants. The gaseous carbonyl compounds were collected on silica gel coated with 2,4-dinitrophenylhydrazine and analyzed by high performance liquid chromatography with ultra-violet detection. The identified and quantified carbonyls were saturated (C1 - C6) and unsaturated (acrolein, methacrolein, crotonaldehyde) aliphatic aldehydes, benzaldehyde, acetone and 2-butanone. Ambient and leaf surface temperatures, relative humidity, light intensity, ozone and nitrogen oxides air levels were monitored during carbonyl emission sampling. With the aim of evaluate the collection system carbonyl background leveIs, 29 air samples were collected from the empty cuvette under laboratory and field conditions. Statistical analysis of the data indicated that the cuvette background leveIs were close to zero under laboratory conditions and increased with the increasing of the sunlight intensity under field conditions. These results showed that the cuvette exposition to the sunlight leaded to positive sampling artifact. Carbonyl compound emission from Ficus benjamina species was measured and high acetaldehyde emission rates were observed under leaf surface temperature higher than 40°C. In the absence of direct sunlight no carbonyl emission was measured from the evaluated individual of Ficus benjamina. Also carbonyI emissions from the following native species in the metropolitan region of São Paulo City were measured: Cecropia pachystachya, Casearia sylvestris, Croton floribundus, Solanum erianthum, Alchornea sidifolia, Syagrus rommanzoffzana e Ficus insípida. The observed rate emissions from these plants ranged between 1,5 10 -2 and 2,3 &#181;gC g-1 h-1.

A técnica de confinamento de folhas de plantas em câmara de Teflon rígido (cuvette), com visor em vidro, submetida a um fluxo contínuo de ar foi adotada na avaliação da emissão de compostos carbonílicos voláteis por plantas. Os carbonílicos foram coletados sobre sílica impregnada com o reagente derivatizante 2,4-dinitrofenilhidrazina e analisados por cromatografia a líquido de alto desempenho e detecção por ultravioleta. Foram identificados e quantificados aldeídos alifáticos saturados (C1 a C6) e insaturados (acroleína, metacroleína, crotonaldeído), benzaldeído, acetona e 2-butanona. A temperatura ambiente e na superfície das folhas, a umidade relativa do ar, a intensidade da luz solar e os níveis de ozônio e de óxidos de nitrogênio no ar foram monitorados durante as coletas de amostras. Com o objetivo de avaliar os níveis de fundo de carbonílicos no sistema coletor empregado, 29 amostras de ar foram coletadas sem a introdução de folhas de planta no cuvette, em condições ambientais de laboratório e campo. Uma avaliação estatística dos resultados indicou que os níveis de fundo do cuvette vazio foram próximos a zero nas coletas feitas no laboratório e aumentaram de acordo com o aumento da intensidade da luz solar nas coletas em campo. Esses resultados mostraram que a exposição do cuvette à radiação solar conduz à formação de artefato positivo de amostragem. Foram feitas medidas da emissão de carbonílicos pela espécie Ficus benjamina, para a qual foram observadas taxas de emissão de acetaldeído altas em condições de temperatura na superfície das folhas superior a 40°C. Na ausência de luz solar incidente, não foi observada emissão de carbonílicos pelo exemplar avaliado dessa espécie. Foram feitas também medidas da emissão de carbonílicos pelas seguintes espécies de plantas ocorrentes na vegetação nativa da Região Metropolitana de São Paulo: Cecropia pachystachya, Casearia sylvestris, Croton floribundus, Solanum erianthum, Alchornea sidifolia, Syagrus rommanzoffiana e Ficus insipida, para as quais foram observadas taxas de emissão de carbonílicos que variaram entre 1,5 10-2 e 2,3 &#181;gC g-1 h-1. / The leaf enclosure technique in air flow-through rigid Teflon chamber (cuvette) was employed to evaluate volatile carbonyl compound emission from plants. The gaseous carbonyl compounds were collected on silica gel coated with 2,4-dinitrophenylhydrazine and analyzed by high performance liquid chromatography with ultra-violet detection. The identified and quantified carbonyls were saturated (C1 - C6) and unsaturated (acrolein, methacrolein, crotonaldehyde) aliphatic aldehydes, benzaldehyde, acetone and 2-butanone. Ambient and leaf surface temperatures, relative humidity, light intensity, ozone and nitrogen oxides air levels were monitored during carbonyl emission sampling. With the aim of evaluate the collection system carbonyl background leveIs, 29 air samples were collected from the empty cuvette under laboratory and field conditions. Statistical analysis of the data indicated that the cuvette background leveIs were close to zero under laboratory conditions and increased with the increasing of the sunlight intensity under field conditions. These results showed that the cuvette exposition to the sunlight leaded to positive sampling artifact. Carbonyl compound emission from Ficus benjamina species was measured and high acetaldehyde emission rates were observed under leaf surface temperature higher than 40°C. In the absence of direct sunlight no carbonyl emission was measured from the evaluated individual of Ficus benjamina. Also carbonyI emissions from the following native species in the metropolitan region of São Paulo City were measured: Cecropia pachystachya, Casearia sylvestris, Croton floribundus, Solanum erianthum, Alchornea sidifolia, Syagrus rommanzoffzana e Ficus insípida. The observed rate emissions from these plants ranged between 1,5 10 -2 and 2,3 &#181;gC g-1 h-1.

Les particules en suspension dans l’air (notées « PM » pour « Particulate matter ») sont aujourd’hui au cœur des préoccupations sociétales en raison de leur impact majeur sur la santé publique et leur forte participation au changement climatique. La matière organique (MO) représente généralement la première composante en masse des PM mais reste encore très mal appréhendée, en particulier la fraction organique d’origine biogénique primaire (PBOA). Des sucres primaires sont proposés comme des traceurs moléculaires pour étudier les processus de transport atmosphérique ainsi que pour estimer la contribution des PBOAs à la masse totale des PM. Cependant, les connaissances sont encore très limitées sur leurs distributions spatiales et temporelles (i.e., cycles journaliers, saisonniers et annuels), leurs principales sources d’émissions, ou encore les facteurs environnementaux qui déterminent leurs concentrations atmosphériques. Par ailleurs, si la comprehension du potentiel oxydant (PO) —proxy de l’effet sanitaire des PM— inhérent à la composante chimique des aérosols a relativement bien avancé ces dernières années, la contribution de cette fraction PBOA est encore est très mal connue. Ces différents aspects constituent les objectifs de ce travail de thèse. D’un point de vue méthodologique, nos questions ont été abordées par une approche interdisciplinaire, qui a impliquée l’exploitation statistique d’une large base de données et le couplage de campagnes de terrain spécifiques avec la mise en œuvre d’une stratégie expérimentale novatrice développée pour l’étude simultanée des caractéristiques chimiques et microbiologiques des échantillons prélevés.Dans un premier travail basé sur l’exploitation d’une large base de données, nous avons montré que les PBOAs constituent une fraction très importante des PM en France, independamment de la typologie de l’environnement, contribuant en moyenne annuelle à 13 ± 4 % de la MO dans les PM10. On met en évidence une similitude entre les évolutions temporelles de concentrations et de ratios entre sucres primaires pour des sites localisés dans une même région géographique (jusqu’à une distance inter-sites d’environ 200 km). Ces observations indiquent que la source PBOA est très homogène spatialement sur des distances cohérentes avec celle de grands types d'écosystèmes. Cette observation a ensuite été validée par une expérimentation basée sur deux échantillonnages annuels de terrain qui nous a permis de démontrer (i) que les évolutions journalières des concentrations atmosphériques en sucres primaires sont déterminées par seulement quelques taxons microbiens atmosphériques, variables d’un point de vue regionale ; et (ii) que ces taxons proviennent respectivement de la flore locale et régionale pour les sites d’étude qui sont directement influencés et non par les activités agricoles. Enfin, dans le cadre d’étude de PO, nos résultats ont permis de démontrer (i) que tous les bioaérosols modèles testés possèdent un PO intrinsèque significatif, comparable pour certaines espèces à celui de composants chimiques atmosphériques modèles connus pour leur forte reactivité redox ; et (ii) qu’ils sont capables d’influencer significativement le PO des PM chimiques modèles ou collectées en condition réelle.Ces travaux apportent un nouveau regard sur l’importance massique des PBOAs et des nouvelles connaissances sur les sources et processus dominants conduisant à leur introduction dans l’atmosphère, ainsi que l’influence des facteurs environnementaux sur ces processus. L’ensemble des résultats de ce travail plaide pour une prise en compte systematique des PBOAs dans les modèles de chimie atmosphérique pour une meilleure prédiction de la qualité de l’air. / Airborne particles (called « PM » for Particulate matter") are nowadays at the core of societal concerns because of their major impact on public health and their strong participation in climate change. Organic matter (OM) generally represents the first mass component of PM but it is still poorly understood, in particular the organic fraction from primary biogenic origin (PBOA). Some specific primary sugars are proposed as molecular tracers to study the atmospheric transport processes as well as to estimate the contribution of PBOAs to the total mass of PM. However, knowledge is still very limited about their spatial and temporal distributions (i.e., daily, seasonal and annual cycles), their main emission sources, or the environmental factors that drive their atmospheric concentrations. Moreover, although the understanding of the oxidative potential (OP) —a proxy of the health effect of PM— inherent in the chemical component of aerosols has progressed quite well in recent years, the contribution of this PBOA fraction is still very poorly understood. These aspects constitute the main objectives of this thesis work. From a methodological point of view, our questions were addressed by an interdisciplinary approach, which involved the statistical exploitation of a large database and the coupling of specific field campaigns with the implementation of an innovative experimental strategy developed for the simultaneous study of the chemical and microbiological characteristics of the samples collected.In a first work based on the exploitation of a large database, we showed that PBOAs constitute a very important fraction of PM in France, regardless of the typology of the environment, contributing on average to 13 ± 4% of the annual MO in PM10. We observed a synchronous temporal trends in both concentrations and ratios between primary sugars species for sites located in the same geographical region (up to an inter-site distance of about 200 km). These observations indicate that the PBOA source is very spatially homogeneous over distances consistent with those of large ecosystem types. This observation was then validated by an experimental approach based on two annual field sampling studies that allowed us to demonstrate (i) that daily changes in atmospheric concentrations of primary sugars are drived by only a few regionally variable atmospheric microbial taxa; and (ii) that these taxa come from local and regional flora for study sites that are directly influenced and not by agricultural activities, respectively. Finally, in the framework of the OP study, our results demonstrated (i) that all the tested model bioaerosols have a significant intrinsic OP, which is comparable for some species to the model atmospheric chemical components known for their high redox reactivity; and (ii) that they can significantly influence the OP of chemical PM models or sampled under real ambient conditions.This work provides a different look into the mass importance of PBOAs and new insights into the dominant sources and processes leading to their introduction into the atmosphere, as well as the influence of environmental factors on these processes. Alltogether these results argue for a systematic consideration of PBOAs in atmospheric chemistry models for better prediction of air quality.