Glaciers are a major source of freshwater around the world, but they are melting at an increased rate due to atmospheric warming resulting from anthropogenic climate change. In addition to temperature increases, light-absorbing particulates on glaciers also are contributing to glacial melt. This research examines how black carbon, released into the air through partial combustion of biofuels, is affecting the surface albedo of glaciers. I also delineate possible sources of black carbon in the Cordillera Blanca region of Peru. Ground data were collected each year from 2011 to 2013 during the local dry season. Effective black carbon (eBC) values were determined using the Light Absorption Heating Method and satellite-derived albedo values were retrieved from NASA’s MODIS MOD10A1 data. Effective black carbon (eBC) values and albedo levels were moderately correlated, showing that albedo decreases with an increase of black carbon, and that this impact can be measured using satellite instruments. Values of eBC did not correlate with spatial proximity to mines, but did correlate with proximity to Huaraz, which likely is the major source of light-absorbing particulates in the region. Further research would benefit from a more extensive source dataset and surface albedo measurements over different seasons.

Durch die Verbrennung von Biomasse werden Partikel freigesetzt, die u.a. schwarzen Kohlenstoff enthalten. Dieser ist wesentlich für die Absorption der solaren Strahlung in der Atmosphäre verantwortlich. Um den Effekt der emmitierten Partikel auf den Strahlungshaushalt quantifizieren zu können, ist die Kenntnis der physikalischen und chemischen Eigenschaften dieser Partikel nötig. Diese sind aber nur zum Teil bekannt. Dieser Bericht beschreibt eine Methode, die optischen Eigenschaften solcher Partikel unter Verwendung bestimmter Annahmen zu berechnen. Auÿerdem wird ein erster Vergleich zwischen berechneten Größen und Messungen aus Laborfeuern durchgeführt. / Biomass burning is an important source for particles containing black carbon, which is known as a strong light absorbing substance. To quantify the effect of such emitted particles on the radiation budget, the knowledge of their physical and chemical properties is necessary. Until now these properties are only partly known. In the following we describe a possibility of calculating the optical properties of such particles using certain simplifications. Also a first comparison between the calculated values and measurements from lab experiments is shown.

Submitted by Inácio de Oliveira Lima Neto (inacio.neto@inpa.gov.br) on 2018-07-13T19:32:04Z No. of bitstreams: 2 Dissertação_Rayner_Monteiro_dos_Santos.pdf: 7681022 bytes, checksum: 3a3a890f9254e37f8dea79e3d2b32b41 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-07-13T19:32:04Z (GMT). No. of bitstreams: 2 Dissertação_Rayner_Monteiro_dos_Santos.pdf: 7681022 bytes, checksum: 3a3a890f9254e37f8dea79e3d2b32b41 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-04-02 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The Amazon, during the wet season, receives dust supplies from the Sahara desert, which is the largest source of global dust. Sporadically, this dust arriving in the Amazon is accompanied by aerosol of biomass burning from the Sahel region. This transatlantic transport can act in the long term in providing essential nutrients to the forest, such as phosphorus. In this work we identify the events and quantify the aerosols transported to the Amazon from the north of Africa by the trade winds. The elemental compositions of the aerosols were investigated from continuous and long-term measurements at three sites in the Central Amazon, north of the city of Manaus, state of Amazonas. From an extensive and diverse database it was possible to determine the elemental concentration of dust aerosols of the Sahara desert and black carbon (Sahel) from Particle Induced X-ray Emission (PIXE) and fluorescence (EDXRF) applied to the filters obtained in a forest region (ZF2). We also used long-term measurements of aerosol optical thickness (AOD) using measurements of two solar photometers from the NASA / AERONET Network in central Amazonia. Aerosols were also analyzed by absorption and scattering measurements of visible radiation by the Matrix Ångström technique. It was also used remote sensing measurements obtained by the NASA-Giovanni system, as well as transport modeling with the HYSPLIT system. A strong seasonality was observed in the aerosol, and the presence of coarse particulate matter is predominant in the rainy season, with a mean volumetric radius ranging from 1.30 μm to 8.71 μm, and this contributes up to 78% of AOD at 500 nm. The highest prevalence of dust aerosols occurred during this same period, with a concentration of 204 ± 604 ng/m 3 , and from 141 pairs of filters, 60 dust-intensive events were identified between 2008 and 2015 represents 85% of traces elementes of dust identified. TheBC in the wet season has low concentrations, with an average of 265 ± 250 ng/m 3 , and has higher concentrations during the dust transport events. The Ångström parameter of scattering and absorption was obtained for the aerosol samples, obtaining during dust transport episodes scattering values ≤ 0.50 and absorption of ≥ 1,11. The analysis of back-trajetories and satellite products obtained with Terra's MODIS sensor confirm that the origin of the air masses are actually Sahara and Sahel. From these results it can be concluded that the highest frequency of dust deposition during the wet season occurs between mid-January and May and that soil dust has an average contribution of 14.6% of the measured total mass and its deposition has a strong impact on the absorption and scattering coefficients of the visible radiation. / A Amazônia, durante a estação chuvosa, recebe aportes de poeira provenientes do deserto do Saara, que é a maior fonte de poeira do solo global. Esporadicamente, essa poeira que chega na Amazônia é acompanhada de aerossol de queima de biomassa proveniente da região do Sahel. Este transporte transatlântico pode atuar a longo prazo no fornecimento de nutrientes essenciais para a floresta, como fósforo. Neste trabalho identificamos os eventos e quantificamos os aerossóis transportados para a Amazônia a partir do norte da África pelos ventos alísios. Investigou-se a composição elementar dos aerossóis a partir de medidas continuas e de longo prazo em três sítios na Amazônia Central, ao norte da cidade de Manaus, estado do Amazonas. A partir de uma extensa e diversificada base de dados foi possível determinar a concentração elementar de aerossóis de poeira do deserto do Saara e black carbon (BC) do Sahel, a partir da écnica de Particle Induced X-ray Emission (PIXE) e fluorescência de raios X por energia dispersiva (EDXRF) aplicada aos filtros obtidos em uma região de floresta (ZF2). Também utilizou-se medidas de longo prazo da espessura ótica de aerossóis (AOD) usando medidas de dois fotômetros solares da Rede NASA/AERONET na região central da Amazônia. Aerossóis também foram analisados através de medidas de absorção e espalhamento de radiação visível pela técnica de Matriz Å ngström. Foram ainda utilizados produtos de medidas de sensoriamento remoto obtidos pelo sistema NASA-Giovanni, além de modelagem de transporte com o sistema HYSPLIT. Observou-se forte sazonalidade no aerossol, e que a presença de material particulado grosso é predominante na estação chuvosa, apresentando um raio volumétrico médio que varia entre 1 e 8 μm, e este contribui com até 78% da AOD em 500 nm. A maior predominância do aerossol de poeira se mostra neste mesmo período, apresentando uma concentração de 204 ± 604 ng/m 3 , e sendo identificados, a partir de 141 pares de filtros, 60 eventos de forte aporte de poeira entre 2008 e 2015, o que representa 85% dos elementos traços de poeira identificados. O BC na estação chuvosa apresenta baixas concentrações, com média de 265 ± 250 ng/m 3 , e apresenta concentrações mais altas nestes eventos. O parâmetro de Å ngström de espalhamento e absorção foi obtido para as amostras de aerossóis, tendo nos episódios de transporte de poeira, valores de espalhamento ≤ 0,50 e absorção de ≥ 1,11. As análises de retrotrajetórias e produtos de satélite obtidos com o sensor MODIS do Terra confirmam que a origem das massas de ar são realmente o Saara e Sahel. A partir desses resultados pode-se concluir que as maiores frequências do aporte de poeira durante a estação chuvosa ocorrem entre meados de janeiro a maio e o forte aporte de poeira tem uma contribuição média de 14,6% da massa total medida, e sua deposição.

Black carbon, a proxy for woodsmoke was measured indoors and outdoors for an occupied residence in Cambria, CA during the winter months of 2009. The purpose was to investigate the infiltration parameters: air exchange rate, deposition rate, and penetration factor. The second part of this study investigated the light absorption properties of organic carbon from residential wood combustion, the dominant fraction of woodsmoke. To assess woodsmoke variation, a study conducted parallel to the one presented in this thesis (Ward, 2009), a grid array of personal emission monitors (PEMS) and aethalometers were placed in a small area, approximately one square kilometer, within a community in Cambria, California between the months of November 2008 and March 2009. In this study, PEMS were used to collect particles on filters, which were analyzed for tracers for woodsmoke, including levoglucosan, elemental carbon, and organic carbon. Aethalometers measured black carbon, an indicator of carbon combustion. Additional PEMS and aethalometers were placed inside one residential home to better understand infiltration of woodsmoke. To model the infiltration of woodsmoke, the Lawrence Berkeley National Laboratory Air Infiltration Model was used. The home of interest was chosen such that indoor sources of particulate matter (PM) were minimal. This insures that all PM measured indoors was from outdoor sources, namely household chimneys. While indoor sources such as indoor fires and resuspension of particles were of concern, homes were chosen to minimize these sources. To investigate the infiltration parameters, four different solution techniques were used. Two of the solution techniques used SOLVER, a Microsoft Excel program, to minimize the sum of squared differences between calculated indoor concentrations and measured indoor concentrations, with all three parameters (air exchange rate, penetration, and deposition) as independent variables. The other two solution techniques used the Air Exchange Rate (AER) model from Lawrence Berkeley National Laboratory (LBNL) (Sherman & Grimsrud, 1980) and then used SOLVER to calculate deposition rate and penetration factor. Solution techniques 1 and 3, which used SOLVER to find all three parameters, had average penetration factors of 0.94 and 0.97 respectively, while solution techniques 2 and 4, which used the LBNL AER model had average penetration factors of 0.85 and 0.78 respectively. The deposition rates for solution techniques 1,2,3, and 4 were 0.10, 0.07, 0.08, and 0.04 hr-1 respectively. The air exchange rates varied throughout the study and ranged from 0.1 to 0.7 hr-1. The average indoor/outdoor ratio was also found to be 0.75. The aerosols derived from the study samples were found to have light absorption properties that were heavily spectrally dependent, which is consistent with expectations for wood combustion aerosols. Conversely, traffic derived aerosols are not found to be heavily spectrally dependent and follow the power law relationship of λ-1 whereas our samples followed λ-1.7 across all wavelengths and λ-2.25 for wavelengths less than 600 nm. The reason for the difference in spectral dependence is the presence of light absorbing organic carbon in wood smoke that is not found in diesel aerosols. The optical absorbances were also calculated for our samples and average values were found to be 3 and 1 m2/g for 370 and 450 nm wavelengths respectively.

Extensive research on soot in snow and snow grain size has been carried out in the Polar Regions. However, North American prairie snowpacks lack observations of soot in snow on snow albedo which adds uncertainty to the overall global effect that black carbon on snow has on climate. Measurements in freshly fallen prairie snowpacks in Northwestern Iowa and Central Texas were collected from February 25 to March 3, 2007 and April 6, 2007, respectively. Multi-day monitoring locations and a frozen lake were study sites at which snow samples were collected to measure soot in snow concentrations. Ancillary measurements were collected at a subset of the sample sites that included: temperature, density, depth, and grain size. At some locations snow reflectance and snow radiance was collected with an Analytical Spectral Device visible/near infra-red spectroradiometer (350 ? 1500 nm). Snow impurity, consisting of light-absorbing particulate matter, was measured by filtering meltwater through a nucleopore 0.4 micrometer filter. Filters were examined using a photometer to measure mass impurity concentration. Soot observations indicate prairie snowpack concentrations ranging from 1 ng C gm^-1 to 115 ng C gm^-1 with an average of 34.9 ng C gm^-1. These measurements are within range of previously published values and can lower snow albedo. As expected, spectral albedo was found to decrease with increasing impurities. Additionally, as grain size increased impurity concentration increased. Differences in soot concentration were observed between the two Iowa snowfall events. The Texas event had higher soot concentrations than both Iowa snowfalls. Validation of an ADEOS-II snow product algorithm that compares simulated radiances to measured sensor radiances for retrieval of snow grain size and mass fraction of soot in snow was attempted using satellite images acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS). The algorithm was unable to uniquely identify a particular snow grain size and soot concentration that would lead to a converging radiance solution in the two spectral bands measured and compared by the algorithm. The in situ data at the validation site fell within published ranges for freshly fallen snow for both snow grain size and soot concentration; however; the closest algorithm retrievals were considerably higher than in situ measurements for both grain size and impurity concentrations.

This thesis explores the factors controlling the distribution of black carbon (BC) in the atmosphere/troposphere and its implications for climate forcing. BC is of great climate interest because of its warming potential. Estimates of BC climate forcing have large uncertainty, in part due to poor knowledge of the distribution of BC in the atmosphere. This dissertation first examines the factors controlling the sources of BC in the Arctic in winter and spring using a global chemical transport model (GEOS-Chem). Emission inventories of BC and wet scavenging of aerosols in the model are updated to reproduce observed atmospheric concentrations of BC as well as observed snow BC content in the Arctic in winter-spring. The simulation shows a dominant contribution of fuel (fossil fuel and biofuel) combustion to BC in Arctic spring. Arctic snow BC content is dominated by fuel combustion sources in winter, but has equal contributions from open fires and fuel combustion in spring. The estimated decrease in Arctic snow albedo due to BC deposition in spring is 0.6%, resulting in a regional surface radiative forcing of 1.2 W m-2. The dissertation then extends the evaluation of the BC simulation to the global scale using aircraft observations over source regions, continental outflow and remote regions and ground-based measurements. The observed low BC concentrations over the remote oceans imply more efficient BC removal than is currently implemented in models. The simulation that has total BC emissions of 6.5 Tg C a-1 and a mean tropospheric lifetime of 4.2 days for 2009 (vs. 6.8 &plusmn 1.8 days for the AeroCom models) captures the principal features of observed BC. The simulation estimates a global mean BC absorbing aerosol optical depth of 0.0017 and a top-of-atmosphere direct radiative forcing (DRF) of 0.19 W m-2, with a range of 0.17-0.31 W m-2 based on uncertainties in the BC atmospheric distribution. The DRF is lower than previous estimates, which could be biased high because of excessive BC concentrations over the oceans and in the free troposphere. / Engineering and Applied Sciences

Using an innovative arrangement of instruments to obtain a comprehensive set of properties, we present a description of the submicron aerosol properties for two distinct regions. During the 2009 SHARP/SOOT campaign in Houston, TX, the average effective density was 1.54 ± 0.07 g cm^-3, consistent with a population comprised largely of sulfates and organics Even in low concentrations (0.31 ± 0.22 µg m^-3), black carbon concentration has a significant impact on the overall density and optical properties. Under prevailing northerly winds, the average black carbon concentration increases from 0.26 ± 0.18 µg m^-3 to 0.60 ± 0.21 µg m^-3. Throughout the campaign, aerosols are often internally mixed, with one peak in the effective density distribution located at 1.55 ± 0.07 g cm^-3. In addition, we conclude that in this region the meteorology has a discernible impact on the concentration and properties of aerosols. After a frontal passage, there is a significant shift in the size distribution as the concentration of <100 nm particles increase and the average effective density decreases to 1.43 ± 0.08 g cm^-3. In Tijuana, Mexico, the submicron aerosols are heavily influenced by vehicle emissions. We observe an average single scattering albedo of 0.75. This average SSA is lower than observed in many US urban environments, and indicates a high concentration of black carbon. The average black carbon concentration is 2.71 ± 2.65 g cm^-3. The aerosol size distributions reveal a high concentration of small particles (< 100 nm) during the day, which are frequently associated with vehicle emissions. Overall, 46 and 81 nm particles are hydrophobic, have an average effective near 1.30 g cm^-3, a higher volatile growth factors than the larger particles, and exhibit a distinct diurnal cycle, which, on average, ranges between 0.80 during the afternoon and 1.70 g cm^-3 overnight. 46 and 81 nm distributions indicate a uniform aerosol composition. 151 and 240 nm aerosols are less cyclical, and the hygroscopicity, volatility, and effect density distributions all exhibit a bimodal distribution, which indicates an external mixture of aerosols. Black carbon and vehicle and industrial organic emissions appear to be the main components of the external mixture.

The Weather Research and Forecasting with Chemistry (WRF-Chem) Model is an “online” regional scale prediction system designed to simulate many detailed meteorological, gas-phase chemical and aerosol processes, with full coupling between the different components. The impacts of aerosol particles are complex and spatially heterogeneous, their impacts varying greatly at the regional scale. Modelling the properties and impacts in a systematic manner requires the coupling between different chemical phases, meteorological and physical parameterisations a model such as WRF-Chem offers. This manuscript documents several developments, and their evaluation, that have been made to the WRF-chem model to improve its representation of detailed gas-phase chemical and aerosol processes. The first study gives an overview of developments made for modeling the North-West European region, including the addition of a new semi-explicit chemical mechanism, N2O5 heterogeneous chemistry and modifications to the sea-spray emissions routine to include fine-mode organic material. The broad impacts of these developments were assessed in the study, while a follow up paper (included in supplementary material) investigated more deeply the impacts of N2O5 heterogeneous chemistry. The second study discusses modifications to WRF-Chem and emission products to improve modelled representation of biomass burning aerosol particles over Brazil. Model results were compared with aircraft measurements and found to represent aerosol particle size distributions and cloud condensation nuclei concentrations reasonably well, but too much biomass burning aerosol were transported up to high altitudes (4-8 km) by the model. In the third study, nested simulations (at higher resolutions than those used in the second study) over Brazil were used to evaluate the impact of aerosol particles on the local radiative balance, by comparing model results from simulations with and with- out aerosol-radiative feedbacks. The instantaneous clear sky aerosol-radiation forcings were found to have a net cooling of -5.0 W m−2 at the top of the atmosphere. Issues with resolving aerosol–cloud interactions, because of the convective parameterisation and differences in model setup across scales, made evaluating semi- and indirect effects impossible.

Several studies indicate that the cabin of buses is the micro-environment in urban public transport where commuters might be the most exposed to black carbon. Black carbon functions as an indicator of air pollution, which is shown to have harmful impacts on the human body and because it may lead to cancers, systemic inflammation, and cardiovascular diseases, it is listed as one of the top causes to premature deaths, globally. This makes it important to understand what mechanisms there are to the elevated levels of pollutants in urban buses, and by performing mobile in-cabin measurements of black carbon concentrations during 55 bus trips in the public transport system of Stockholm, this study have tried to assess the influences from using different types of fuel, self-contamination, meteorological conditions and driving factors. Although concentrations showed large variability both spatially and temporally, idling at intensely trafficked bus stops showed an average increase of concentrations by 42% compared to the overall average. The risk of allowing increased number of pollutants at bus stops increases with idling for longer time and having the doors open meanwhile.

At international border areas that suffer from poor quality, assessment of pollutant sources and transport across the border is important for designing effective air quality management strategies. As part of the Cal-Mex 2010 field campaign at the US-Mexico border in San Diego and Tijuana, we measured black carbon (BC) concentrations at three locations in Mexico and one in the United States. The measurements were intended to support the following objectives: to characterize the spatial and temporal variability in BC concentrations and emissions in the border region, to identify potential source areas of BC emissions, and to characterize the cross-border transport of BC and assess its impact on local and regional air quality. BC concentrations at Parque Morelos, the campaign's supersite, averaged 2.1 ?g m?? and reached a maximum value of 55.9 ?g m??. This average value is comparable to levels in large American cities like Los Angeles and similarly sized Mexican cities like Mexicali. The maximum value occurred near midnight, and similar incidents were observed on nearly half of the overnight monitoring periods. BC and carbon monoxide (CO) were strongly correlated at the Mexican sites. The BC/CO ratio was ~3 times higher in Tijuana than in Mexico City, suggesting that gasoline-powered vehicles in Tijuana emit more BC than is typical or that diesel vehicles comprise a relatively high proportion of the vehicle fleet. Tijuana's emissions of BC are estimated to be 380-1470 metric tons yr??. BC measurements were used in conjunction with modeled wind fields to simulate forward and backward particle trajectories. Generally, BC in Tijuana appears to originate locally, as backward simulations showed transport from the US into Mexico at only one site. The majority of the trajectory analyses indicate that there is often transport from Tijuana into the US, crossing the border in a northeasterly direction to the east of San Diego-Tijuana and sometimes as far east as Imperial County at the eastern edge of California. These results suggest that any air quality management strategies considering BC should account for contributions from the border region, as BC is chemically inert in the atmosphere and can travel up to thousands of kilometers. / Master of Science