Matching Items (7)
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- All Subjects: Particulate matter
- Creators: Herckes, Pierre
- Creators: Buttry, Daniel
Description
Americans spend upwards of 90% of their time indoors, hence indoor air quality (IAQ) and the impact of IAQ on human health is a major public health concern. IAQ can be negatively impacted by outdoor pollution infiltrating indoors, the emission of indoor pollutants, indoor atmospheric chemistry and poor ventilation. Energy saving measures like retrofits to seal the building envelope to prevent the leakage of heated or cooled air will impact IAQ. However, existing studies have been inconclusive as to whether increased energy efficiency is leading to detrimental IAQ. In this work, field campaigns were conducted in apartment homes in Phoenix, Arizona to evaluate IAQ as it relates to particulate matter (PM), carbonyls, and tobacco specific nitrosamines (TSNA).
To investigate the impacts of an energy efficiency retrofit on IAQ, indoor and outdoor air quality sampling was carried out at Sunnyslope Manor, a city-subsidized senior living apartment complex. Measured indoor formaldehyde levels before the building retrofit exceeded reference exposure limits, but in the long term follow-up sampling, indoor formaldehyde decreased for the entire study population by a statistically significant margin. Indoor PM levels were dominated by fine particles and showed a statistically significant decrease in the long term follow-up sampling within certain resident subpopulations (i.e. residents who reported smoking and residents who had lived longer at the apartment complex). Additionally, indoor glyoxal and methylglyoxal exceeded outdoor concentrations, with methylglyoxal being more prevalent pre-retrofit than glyoxal, suggesting different chemical pathways are involved. Indoor concentrations reported are larger than previous studies. TSNAs, specifically N'-nitrosonornicotine (NNN), 4-(methyl-nitrosamino)-4-(3-pyridyl)-butanal (NNA) and 4-(methylnitrosoamino)-1-(3-pyridyl)-1-butanone (NNK) were evaluated post-retrofit at Sunnyslope Manor. Of the units tested, 86% of the smoking units and 46% of the non-smoking units had traces of at least one of the nitrosamines.
To investigate the impacts of an energy efficiency retrofit on IAQ, indoor and outdoor air quality sampling was carried out at Sunnyslope Manor, a city-subsidized senior living apartment complex. Measured indoor formaldehyde levels before the building retrofit exceeded reference exposure limits, but in the long term follow-up sampling, indoor formaldehyde decreased for the entire study population by a statistically significant margin. Indoor PM levels were dominated by fine particles and showed a statistically significant decrease in the long term follow-up sampling within certain resident subpopulations (i.e. residents who reported smoking and residents who had lived longer at the apartment complex). Additionally, indoor glyoxal and methylglyoxal exceeded outdoor concentrations, with methylglyoxal being more prevalent pre-retrofit than glyoxal, suggesting different chemical pathways are involved. Indoor concentrations reported are larger than previous studies. TSNAs, specifically N'-nitrosonornicotine (NNN), 4-(methyl-nitrosamino)-4-(3-pyridyl)-butanal (NNA) and 4-(methylnitrosoamino)-1-(3-pyridyl)-1-butanone (NNK) were evaluated post-retrofit at Sunnyslope Manor. Of the units tested, 86% of the smoking units and 46% of the non-smoking units had traces of at least one of the nitrosamines.
ContributorsFrey, Sarah E (Author) / Herckes, Pierre (Thesis advisor) / Fraser, Matthew P (Thesis advisor) / Destaillats, Hugo (Committee member) / Chizmeshya, Andrew (Committee member) / Arizona State University (Publisher)
Created2014
Description
Dielectrophoresis (DEP) is a technique that influences the motion of polarizable particles in an electric field gradient. DEP can be combined with other effects that influence the motion of a particle in a microchannel, such as electrophoresis and electroosmosis. Together, these three can be used to probe properties of an analyte, including charge, conductivity, and zeta potential. DEP shows promise as a high-resolution differentiation and separation method, with the ability to distinguish between subtly-different populations. This, combined with the fast (on the order of minutes) analysis times offered by the technique, lend it many of the features necessary to be used in rapid diagnostics and point-of-care devices.
Here, a mathematical model of dielectrophoretic data is presented to connect analyte properties with data features, including the intercept and slope, enabling DEP to be used in applications which require this information. The promise of DEP to distinguish between analytes with small differences is illustrated with antibiotic resistant bacteria. The DEP system is shown to differentiate between methicillin-resistant and susceptible Staphylococcus aureus. This differentiation was achieved both label free and with bacteria that had been fluorescently-labeled. Klebsiella pneumoniae carbapenemase-positive and negative Klebsiella pneumoniae were also distinguished, demonstrating the differentiation for a different mechanism of antibiotic resistance. Differences in dielectrophoretic behavior as displayed by S. aureus and K. pneumoniae were also shown by Staphylococcus epidermidis. These differences were exploited for a separation in space of gentamicin-resistant and -susceptible S. epidermidis. Besides establishing the ability of DEP to distinguish between populations with small biophysical differences, these studies illustrate the possibility for the use of DEP in applications such as rapid diagnostics.
Here, a mathematical model of dielectrophoretic data is presented to connect analyte properties with data features, including the intercept and slope, enabling DEP to be used in applications which require this information. The promise of DEP to distinguish between analytes with small differences is illustrated with antibiotic resistant bacteria. The DEP system is shown to differentiate between methicillin-resistant and susceptible Staphylococcus aureus. This differentiation was achieved both label free and with bacteria that had been fluorescently-labeled. Klebsiella pneumoniae carbapenemase-positive and negative Klebsiella pneumoniae were also distinguished, demonstrating the differentiation for a different mechanism of antibiotic resistance. Differences in dielectrophoretic behavior as displayed by S. aureus and K. pneumoniae were also shown by Staphylococcus epidermidis. These differences were exploited for a separation in space of gentamicin-resistant and -susceptible S. epidermidis. Besides establishing the ability of DEP to distinguish between populations with small biophysical differences, these studies illustrate the possibility for the use of DEP in applications such as rapid diagnostics.
ContributorsHilton, Shannon (Author) / Hayes, Mark A. (Thesis advisor) / Borges, Chad (Committee member) / Herckes, Pierre (Committee member) / Arizona State University (Publisher)
Created2019
Description
Metal-organic frameworks (MOFs) are a new set of porous materials comprised of metals or metal clusters bonded together in a coordination system by organic linkers. They are becoming popular for gas separations due to their abilities to be tailored toward specific applications. Zirconium MOFs in particular are known for their high stability under standard temperature and pressure due to the strength of the Zirconium-Oxygen coordination bond. However, the acid modulator needed to ensure long range order of the product also prevents complete linker deprotonation. This leads to a powder product that cannot easily be incorporated into continuous MOF membranes. This study therefore implemented a new bi-phase synthesis technique with a deprotonating agent to achieve intergrowth in UiO-66 membranes. Crystal intergrowth will allow for effective gas separations and future permeation testing. During experimentation, successful intergrown UiO-66 membranes were synthesized and characterized. The degree of intergrowth and crystal orientations varied with changing deprotonating agent concentration, modulator concentration, and ligand:modulator ratios. Further studies will focus on achieving the same results on porous substrates.
ContributorsClose, Emily Charlotte (Author) / Mu, Bin (Thesis director) / Shan, Bohan (Committee member) / Chemical Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12
Description
X-ray crystallography is the most widely used method to determine the structure of proteins, providing an understanding of their functions in all aspects of life to advance applications in fields such as drug development and renewable energy. New techniques, namely serial femtosecond crystallography (SFX), have unlocked the ability to unravel the structures of complex proteins with vital biological functions. A key step and major bottleneck of structure determination is protein crystallization, which is very arduous due to the complexity of proteins and their natural environments. Furthermore, crystal characteristics govern data quality, thus need to be optimized to attain the most accurate reconstruction of the protein structure. Crystal size is one such characteristic in which narrowed distributions with a small modal size can significantly reduce the amount of protein needed for SFX. A novel microfluidic sorting platform was developed to isolate viable ~200 nm – ~600 nm photosystem I (PSI) membrane protein crystals from ~200 nm – ~20 μm crystal samples using dielectrophoresis, as confirmed by fluorescence microscopy, second-order nonlinear imaging of chiral crystals (SONICC), and dynamic light scattering. The platform was scaled-up to rapidly provide 100s of microliters of sorted crystals necessary for SFX, in which similar crystal size distributions were attained. Transmission electron microscopy was used to view the PSI crystal lattice, which remained well-ordered postsorting, and SFX diffraction data was obtained, confirming a high-quality, viable crystal sample. Simulations indicated sorted samples provided accurate, complete SFX datasets with 3500-fold less protein than unsorted samples. Microfluidic devices were also developed for versatile, rapid protein crystallization screening using nanovolumes of sample. Concentration gradients of protein and precipitant were generated to crystallize PSI, phycocyanin, and lysozyme using modified counterdiffusion. Additionally, a passive mixer was created to generate unique solution concentrations within isolated nanowells to crystallize phycocyanin and lysozyme. Crystal imaging with brightfield microscopy, UV fluorescence, and SONICC coupled with numerical modeling allowed quantification of crystal growth conditions for efficient phase diagram development. The developed microfluidic tools demonstrated the capability of improving samples for protein crystallography, offering a foundation for continued development of platforms to aid protein structure determination.
ContributorsAbdallah, Bahige G (Author) / Ros, Alexandra (Thesis advisor) / Buttry, Daniel (Committee member) / Hayes, Mark (Committee member) / Arizona State University (Publisher)
Created2016
Description
Quantifying halogen presence and speciation in particulate matter is crucial given the role atmospheric particulates play in transport and cycling. While some halogens (fluorine and chlorine) are often included in aerosol studies, iodine and bromine have rarely been examined, especially outside of a marine environment. Focus on this environment is, in part, due to the existence of biogenic marine sources for both halogens. However, examining iodine and bromine in an urban environment has the potential to provide key insights into the transport and processing of these species in the atmosphere. As Tempe is set within a desert environment, bromine concentration is expected to be relatively high due to its presence in Earth’s crust, while iodine is expected to exist in higher concentrations near the coast. To detect presence and concentration, ICP-MS analysis was performed on samples taken in Tempe, AZ as well as sites in Bakersfield, CA and Davis, CA, which yielded preliminary results in line with these expectations. A secondary set of samples were taken in Tempe, AZ during dust storms, haboobs, and winter holidays. CIC was used to determine the organic fraction. In doing so, this study aims to identify species present in an urban environment as well as potential transportation pathways.
ContributorsLoera, Lourdes (Author) / Herckes, Pierre (Thesis director) / Richert, Ranko (Committee member) / Fraser, Matthew (Committee member) / Barrett, The Honors College (Contributor) / School of Molecular Sciences (Contributor) / School of Human Evolution & Social Change (Contributor)
Created2023-05
Description
Atmospheric particulate matter (PM) has a pronounced effect on our climate, and exposure to PM causes negative health outcomes and elevated mortality rates in urban populations. Reactions that occur in fog can form new secondary organic aerosol material from gas-phase species or primary organic aerosols. It is important to understand these reactions, as well as how organic material is scavenged and deposited, so that climate and health effects can be fully assessed. Stable carbon isotopes have been used widely in studying gas- and particle-phase atmospheric chemistry. However, the processing of organic matter by fog has not yet been studied, even though stable isotopes can be used to track all aspects of atmospheric processing, from particle formation, particle scavenging, reactions that form secondary organic aerosol material, and particle deposition. Here, carbon isotope analysis is used for the first time to assess the processing of carbonaceous particles by fog.
This work first compares carbon isotope measurements (δ13C) of particulate matter and fog from locations across the globe to assess how different primary aerosol sources are reflected in the atmosphere. Three field campaigns are then discussed that highlight different aspects of PM formation, composition, and processing. In Tempe, AZ, seasonal and size-dependent differences in the δ13C of total carbon and n-alkanes in PM were studied. δ13C was influenced by seasonal trends, including inversion, transport, population density, and photochemical activity. Variations in δ13C among particle size fractions were caused by sources that generate particles in different size modes.
An analysis of PM from urban and suburban sites in northeastern France shows how both fog and rain can cause measurable changes in the δ13C of PM. The δ13C of PM was consistent over time when no weather events occurred, but particles were isotopically depleted by up to 1.1‰ in the presence of fog due to preferential scavenging of larger isotopically enriched particles. Finally, the δ13C of the dissolved organic carbon in fog collected on the coast of Southern California is discussed. Here, temporal depletion of the δ13C of fog by up to 1.2‰ demonstrates its use in observing the scavenging and deposition of organic PM.
This work first compares carbon isotope measurements (δ13C) of particulate matter and fog from locations across the globe to assess how different primary aerosol sources are reflected in the atmosphere. Three field campaigns are then discussed that highlight different aspects of PM formation, composition, and processing. In Tempe, AZ, seasonal and size-dependent differences in the δ13C of total carbon and n-alkanes in PM were studied. δ13C was influenced by seasonal trends, including inversion, transport, population density, and photochemical activity. Variations in δ13C among particle size fractions were caused by sources that generate particles in different size modes.
An analysis of PM from urban and suburban sites in northeastern France shows how both fog and rain can cause measurable changes in the δ13C of PM. The δ13C of PM was consistent over time when no weather events occurred, but particles were isotopically depleted by up to 1.1‰ in the presence of fog due to preferential scavenging of larger isotopically enriched particles. Finally, the δ13C of the dissolved organic carbon in fog collected on the coast of Southern California is discussed. Here, temporal depletion of the δ13C of fog by up to 1.2‰ demonstrates its use in observing the scavenging and deposition of organic PM.
ContributorsNapolitano, Denise (Author) / Herckes, Pierre (Thesis advisor) / Fraser, Matthew (Committee member) / Shock, Everett (Committee member) / Arizona State University (Publisher)
Created2018
Description
-Please adjust the format of the abstract. m-3 should be typed as "m to the minus 3" with the "minus 3" in superscript
-see the additional "abstract.pdf" document for formatting
In arid environments like Phoenix, many professional and residential outdoor spaces are cooled by the use of misting systems. These systems spray a fine mist of water droplets that cool down the surrounding air through the endothermic evaporation process. When the water droplets evaporate, they leave behind dissolved material that is present in the water, generating ambient particulate matter (PM). Thus, misting systems are a point source of PM. Currently there is no information on their impact on air quality in close proximity to these systems, or on the chemical composition of the particulate matter generated by the evaporating mist.
In this project, PM concentrations are found to increase on average by a factor of 8 from ambient levels in the vicinity of a residential misting system in controlled experiments. PM concentrations in public places that use misting systems are also investigated. The PM10 concentrations in public places ranged from 0.102 ± 0.010 mg m-3 to 1.47 ± 0.15 mg m-3, and PM2.5 ranged from 0.095 ± 0.010 mg m-3 to 0.99 ± 0.10 mg m-3. Air quality index (AQI) values based on these concentrations indicate that these levels of PM range from unhealthy to hazardous in most cases. PM concentrations tend to decrease after remaining relatively constant with increasing distance from misting systems. Chemical data reveal that chloride and magnesium ions may be used as tracers of aerosolized water from misting systems. The average chloride concentration was 71 µg m-3 in misting samples and below the detection limit for Cl- (< 8.2 µg m-3) in ambient samples. The average magnesium concentration was 11.7 µg m-3 in misting samples and 0.23 µg m-3 in ambient samples.
-see the additional "abstract.pdf" document for formatting
In arid environments like Phoenix, many professional and residential outdoor spaces are cooled by the use of misting systems. These systems spray a fine mist of water droplets that cool down the surrounding air through the endothermic evaporation process. When the water droplets evaporate, they leave behind dissolved material that is present in the water, generating ambient particulate matter (PM). Thus, misting systems are a point source of PM. Currently there is no information on their impact on air quality in close proximity to these systems, or on the chemical composition of the particulate matter generated by the evaporating mist.
In this project, PM concentrations are found to increase on average by a factor of 8 from ambient levels in the vicinity of a residential misting system in controlled experiments. PM concentrations in public places that use misting systems are also investigated. The PM10 concentrations in public places ranged from 0.102 ± 0.010 mg m-3 to 1.47 ± 0.15 mg m-3, and PM2.5 ranged from 0.095 ± 0.010 mg m-3 to 0.99 ± 0.10 mg m-3. Air quality index (AQI) values based on these concentrations indicate that these levels of PM range from unhealthy to hazardous in most cases. PM concentrations tend to decrease after remaining relatively constant with increasing distance from misting systems. Chemical data reveal that chloride and magnesium ions may be used as tracers of aerosolized water from misting systems. The average chloride concentration was 71 µg m-3 in misting samples and below the detection limit for Cl- (< 8.2 µg m-3) in ambient samples. The average magnesium concentration was 11.7 µg m-3 in misting samples and 0.23 µg m-3 in ambient samples.
ContributorsKnight, William Louis (Co-author) / Knight, William (Co-author) / Herckes, Pierre (Thesis director) / Fraser, Matthew (Committee member) / Hamilton, Kerry (Committee member) / School of Sustainability (Contributor) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05