Particulate matter (PM) and tropospheric ozone are air pollutants that are harmful to human health and have broad implications for climate. Despite their importance, there remain large uncertainties related to their sources, evolution in the atmosphere, and impact downwind. In this thesis, I work to address some of these uncertainties through integrated analysis of ground, aircraft, and satellite observations and using both forward and inverse modeling approaches. A new, high-resolution database of ozone-CO correlations was developed from two separate satellite platforms and was validated against in-situ profiles of the trace gases from commercial aircraft. These correlations were interpreted with a state-of-the-science global chemical transport model (CTM) to infer constraints on ozone sources. The observations supported the major source representation in the model for polluted North American outflow in June-July-August (combustion sources) and for the observed ozone maximum in the South Atlantic during December-January-February (lightning). A major model discrepancy was revealed over the North Pacific in summer and fall that was related to an overestimate of the natural lightning source and an underestimate of East Asian anthropogenic emissions. Land clearing by fire in Equatorial Asia pollutes the air shed of one of the most densely populated regions in the world, but fires set in different areas have very different public health implications depending on the population downwind. Smoke exposure sensitivity to Equatorial Asian fires for several receptor locations was calculated with the adjoint of a global CTM. Peatswamp fires in southern Sumatra were found to be particularly detrimental to public health for all years studied, implying that an effective land management policy protecting the remaining peatswamp forests would be of great air quality benefit. This approach can be used to estimate PM exposure for any future fire emission scenario and can be used to provide guidance for targeted land conservation in Equatorial Asia. We use an ensemble of surface, aircraft, and satellite observations over the Southeast US during the summer-fall of 2013 together with the GEOS-Chem CTM at high resolution to better understand aerosol sources in the region and the relationship between surface PM and aerosol optical depth (AOD). Sulfate and organic aerosol (OA) are the main contributors to surface PM2.5 (mass concentration of PM finer than 2.5 μm aerodynamic diameter) and AOD over the Southeast US, with OA acquiring an increasing role over the past decade as anthropogenic emissions have declined. Biogenic isoprene and monoterpenes are the dominant source of OA, and may contribute to sulfate formation through the production of Criegee intermediates as SO2 oxidants. The vertical profile of aerosol extinction over the Southeast US follows closely that of aerosol mass. The SEAC4RS aircraft data demonstrate that the AODs measured from space are fundamentally consistent with surface PM2.5. This implies that satellites can be used reliably to infer PM2.5 air quality if a good CTM representation of the aerosol vertical distribution is available. / Earth and Planetary Sciences

Water treatment is a critical global challenge requires innovated effective solution. Conventional treatment methods includes membrane filtration, adsorption and electrochemical oxidation of organics. This dissertation proposed a new hybrid of the three conventional technologies and investigated the mechanism and application potential for water treatment using carbon nanotube (CNT) based anodic filter. A qualitative reactive transport model consisting of mass transport, adsorption/desorption, electron transfer was developed to understand reaction mechanism and compare the filtration with the batch electrochemical system. The mass transport step is found to be the key advantage (>6-fold) of the electrochemical filtration over the batch system due to convective mass transport through the filter pores. This indicate synergy between the filtration and the electrochemisty. A quantitative model coupling the above three steps was also build to quantitatively simulate the reaction kinetics and probe information about reactive sites. The model simulation was successfully validated by experimental methyl orange oxidation data and was further used to identify kinetics from reactive sites. It was found that two types of reactive sites–the sidewall sites and oxy-defect sits are both reactive for ferrocyanide oxidation with a slightly different overpotential. Also, microscopic flux and steamline plot again verify the convective mass transport enhance reaction kinetics–synergy of the filtration and electrochemistry. To improve potential for organic oxidation applications, the CNT filter was coated with 3.9±1.5 nm bismuth-doped tin oxide (BTO) nanoparticles. In the oxalate oxidation experiments, the current efficiency increased by 1.5–3.5 times and TOC removal increased by 2–8 times after coating. The BTO-CNT anode energy consumption was 25.7 kWh kgCOD-1 at ~93% TOC removal and 8.6 kWh kgCOD-1 at ~50% TOC removal, comparable to state-of-the-art oxalate oxidation processes (22.5–81.7 kWh kgCOD-1). The anode stability also improved by extending the working potential range from 1.4 V of pure CNT to 2.2 V of BTO coated CNT. For inorganic ion removal applications, the CNT filter was coated by a 5.5 ± 2.7 nm layer of TiO2 for arsenic removal. Compared with the conventional adsorption column using granular adsorbents, the TiO2-CNT filter is a highly dispersed nano-system allows forced convective transport through the pores whereas diffusive mass transport dominates and limits kinetics for granular adsorbents. As a result, adsorption kinetics of the TiO2-CNT filter increased by two orders of magnitude due to structure improved site accessibility (20–30 fold), internal convection (4–6 fold) and electrosorption (0.15–2 fold). Groundwater samples containing 44 ppb As were treated by single-pass filtration, and 12500 bed volumes (residence time of 4.5 s; 127 L m-2 h-1; 5.8 mg m-2 h-1). TiO2 filter was successfully regenerated by 5 mM NaOH for both As(III) and As(V). / Engineering and Applied Sciences - Engineering Sciences

Organic and microbial fouling are the initial steps for biofilm formation, resulting in severe fouling problems in many environmental and engineered applications including membrane water filtration. Electro-active methods are proposed to mitigate microbial as well as organic fouling via electrokinetic and/or electrochemical mechanisms. In the first part of this thesis, a parallel-electrode configuration was adopted and the cathode antifouling was evaluated. A carbon nanotube-polyvinylidene fluoride (CNT-PVDF) porous non-Faradaic cathode was first fabricated on top of an ultrafiltration (UF) membrane to produce negative surface charges via capacitive charging at 2 V, which reduced energy requirements (up to 2-fold) in comparison to the unmodified control. A semi-quantitative study was then completed on cathode coatings of different nanomaterials (CNM) to reduce microbial fouling. The bacterial attachment and inactivation were correlated to the electric potential and cathodic H2O2 generation, respectively. Next, a CNT and carbon black (CB) composite cathode was made on a forward osmosis (FO) membrane surface and challenged with synthetic and actual wastewater, which reduced fouling in regard to initial flux loss (~60%) for the actual wastewater and fouling rate (~50%) for both solutions at 2 V in 84 h. In the other part of the thesis, the electrode configuration was improved by fabricating interlaced surface electrodes on a substrate or membrane surface instead of only using a cathode. Insulated interlaced Ag electrodes resulted in optimal bacterial inactivation (84%) and detachment (94% after 15 h biofilm growth) with 2 min treatment at 50 V AC (10 kHz). Interlaced CNT electrodes on a microfiltration (MF) membrane altered the bacterial density and morphology at 2 V DC and reduced the fouling rate by up to 75% under the optimal filtration conditions at 2 V AC. / Engineering and Applied Sciences - Engineering Sciences

Stable water isotopes (H2O, H18O, and HDO) are incorporated into the microphysics schemes of two different atmospheric models. This thesis describes the use of these molecules as tracers in precipitation budgets to assess the processes controlling the isotopic signatures of precipitation in the tropics and orographic snow in the mid-latitudes. The idealized simulations of seasonal precipitation budgets in the tropics determine that increased vapor convergence during intense precipitation is most important for setting the isotopic composition of the convective precipitation. The isotopic signal of the converged vapor is more important than the local evaporation and smaller scale post-condensational processes. Flow over a 2D-mountain and realistic simulations of orographic clouds show that the isotopic signature of precipitation is more sensitive to changes in mountain height and initial temperature profiles than to the cloud droplet number concentration. Riming of cloud liquid and vapor deposition onto ice are the largest source terms for orographic precipitation, and have distinct isotopic signatures that are altitude-dependent. When riming is the larger source term, precipitation tends to be more enriched than when vapor deposition dominates. / Earth and Planetary Sciences

Remote islands face increasingly pressing constraints in their efforts to satisfy their waste management, energy, and water needs in a sustainable manner. Their small scale and isolated context restrict the availability of natural resources and infrastructure commonly available in mainland regions, which facilitates an adverse dependency on imports and exclusive use of landfilling. This thesis aims to investigate systemic solutions to the waste management, energy and water problems encountered by insulated communities. Analysis evaluates the benefits and costs of a novel network based on a waste-to-energy facility against the business-as-usual methods in the region of the Northern Aegean Sea in Greece. The economic, social, and environmental sustainability of the two systems is evaluated through a cost-benefit analysis, using a comprehensive set of economic, environmental, and social indicators. Two main alternatives were investigated; an ENERGOS gasification plant and an Enerkem waste-to-biofuels plant. Results show that the current system is economically and environmentally unsustainable and that substantial benefits are achieved through the development of the proposed network. The results also revealed that the possibility to produce biofuels is not only the most economically, environmentally and socially feasible alternative, but also fosters several synergies and the development of a circular economy at the regional scale. The results of the analysis facilitate prudent decision-making with regard to natural resource management in island regions and can be utilized by other groups of islands with similar waste generation levels and challenges.

This study was focused on analyzing the Facility Environmental Module (FEM) of the Sustainable Apparel Coalition’s (SAC) Higg Index. The research objectives were twofold: 1) to test whether the indicators featured in the FEM could accommodate the data requirements for calculating environmental impacts of apparel products, and 2) to identify if the FEM indicators could satisfy the data and information needs of other key stakeholder groups. The long track record of irresponsible social and environmental practices in the apparel industry began gaining more attention in the press toward the end of the 20th century. Since then, many companies have been prompted to introduce sustainability practices in response to business-threatening criticisms. While these measures helped companies manage their supply chains better, for the most part the improvements remained at the scale of individual companies, limiting their effectiveness in implementing systemic change in the apparel industry. The potential for improving sustainability across the industry rests in the ability for apparel companies to engage collaboratively toward the common goal. Helping to facilitate this objective is the Higg Index, the SAC’s self-assessment suite of tools. The Index is presently composed of three modules, which use a standardized scoring methodology to rate the performance of an apparel company’s brand, facilities, and products, respectively. One of the issues with the current state of the Index is the lack of connectivity between the product and facility modules. Because the processes conducted at the facility level have a direct impact on the embedded impacts of the product, it is important to consider these factors when assessing the lifecycle implications of a given product. The second issue considered in this study is that facilities are often confronted with external pressures to report, comply, and seek certifications related to environmental performance. In practice, this requires completing data and information requests similar to those of the Higg Index. However, these tasks can be burdensome for facility managers who may need to gather data from multiple sources. If the FEM and other Higg Index modules were structured in such a way that they could reduce the time and effort required to complete other requests for information they would likely be more easily adopted. A gap analysis approach was used to test the FEM’s ability to yield valuable data for product LCAs and to understand its potential synergies with other data and information requests. First, the metrics that could be expected from a completed FEM were compared against the requirements of the product LCA methodology using a restructured excel file. This file featured all FEM key performance indicators (KPI) and included dedicated columns for mapping the criteria for data needed by each LCA impact category methodology. The second test involved using a similar excel-based tool to assess the equivalencies between the FEM KPIs and those featured in two example external frameworks: the Fair Trade Product Standard and the Cradle to Cradle Standard. Based on the results of these gap analyses, it became clear that there is significant potential to improve the assessment of facilities’ performance through the introduction of more quantitative KPIs. This would be required to calculate relative impacts for product LCAs and it would also help facilities gain a better understanding of their performance. It is therefore recommended that the SAC reassess the KPIs featured in the FEM and request more quantitative metrics. Additionally, continuing to evaluate the equivalencies of other sustainability frameworks may help the SAC to identify common KPIs that are asked by external organizations but not included in the FEM. These elements could then be incorporated into a future version of the FEM for a more comprehensive assessment of facility environmental performance.

The capture of methane from waste disposal facilities can have a significant impact on the reduction of anthropogenic methane emissions. In the United States, more than six hundred facilities are capturing approximately 26.3 MMTCO2e methane annually (U.S. EPA, 2015). The importance of the capture is two-fold: reduction of greenhouse gases and the exploitation of a beneficial energy source. Yet methane capture efficiencies have been moderate due to many logistical issues. Few methods currently exist to rehabilitate marginally producing extraction wells at landfills. This study was designed to test whether post-perforation technology, invented in 2009, is effective in increasing the efficiency of gas capture from marginally producing wells. This study examined the effectiveness of post-perforation technology to improve the environmental and energy benefits associated with additional methane capture. Post perforation technology was designed and developed to rehabilitate marginal extraction wells. The technology creates new openings to allow more methane to enter an extraction well. Prior to this technology low yield or marginal extraction wells were abandoned and new extraction wells were drilled and installed. The study consisted of gathering data from nine existing municipal solid waste facilities that had extraction wells previously post-perforated. After review, five of the nine facilities were selected for the study. For adequate sample size, facilities with nine or more post-perforated extraction wells were included in this study. The number of post perforated wells from the five facilities ranged from 9 to 19. All facilities were from Texas or Florida. Post-perforation at these facilities was conducted between September 2009 and October 2014. The number of methane extraction wells from the five facilities ranged from 49 to 138. Measurements for % methane (CH4), initial flow (standard cubic feet per minute scfm) and adjusted flow (scfm) were obtained at each extraction well at least on a monthly basis. One year’s worth of data was obtained at each facility, six months prior and six month after post-perforation for each extraction well. All extraction at each of the five facilities wells were categorized into one of three groups for analyses based on the following criteria. If the initial flow was ≤2 (scfm) or the % methane was ˂50% the extraction well was a candidate for post-perforation. If this type of extraction well was subsequently post-perforated, it was categorized into group 1, but if not selected for post-perforation it was categorized into group 2, serving as a control group within that landfill. However, if the initial flow was >3 (scfm) the extraction wells was categorized into group 3. The total sample size for group 1 was 67, group 2 contained 165, and group 3 contained 261 extraction wells. The results of the analyses demonstrated a statistical effect after post-perforation on the initial flow (scfm) and on adjusted flow (scfm) in Group 1, the treatment group. The mean initial flow after post-perforation increased from 16.9 to 28.5 scfm (t = 3.05; p = 0.016; n=67), and the adjusted flow increased from 16.8 to 30.1 scfm (t = 3.66; p = 0.002; n=67). Group 2 and Group 3 mean values also increased after the time of perforation of Group 1 wells, but with not as large an increase in either variable. The added methane capture from landfills yielded substantial environmental and energy benefits. Four facilities yielded mean flow increases of methane at 125, 157, 120 and 558 scfm, for a total 960 scfm methane. The increase from those four facilities represents a total equivalent emission reduction of 0.1329 MMTCO2E/year, equivalent to 5,336 tons of CH4/year or 13,171 tons of CO2/ year. The energy benefit from 960 scfm could heat 3,315 homes for a year. This study demonstrates that post-perforation does increase the capture of methane in extraction wells at municipal solid waste facilities. Furthermore, this study demonstrated the advantages to be gained from any methodology or innovation that decreases fugitive emissions from landfills. Further research is required to increase the efficiency of methane capture. Industry change is slow due to the inconsistencies between federal, state and local regulatory requirements, but this study helps point the way.

The application of the widely used mass balance model in determining portable air purifier (PAP) effectiveness in particulate matter (PM) removal was not validated in occupied residential settings. The corresponding size-resolved information and measurements for the model parameters and PAP effectiveness were also limited to better characterize human exposure to indoor PM. Additionally, effects of ambient factors, such as meteorology, and their long-term impacts on occupant indoor exposure to outdoor PM was unclear. We achieved well-mixed environment and steady state of PM concentrations that met the mass balance model assumptions. Size-resolved particle deposition rate was determined using non-linear mixed effects model, whereas linear mixed effects model was used to estimate the slope between the measured and modeled effectiveness for validation purpose. To evaluate the impact of ambient factors on PM exposure, we assembled data from two cohorts in the greater Boston area, assessing the monthly and long-term effect of temperature and other meteorology on Sr. Long-term meteorology was projected using 15 weather models for the past and future 20 years to estimate Sr for the corresponding periods with mixed effects models. Both particle deposition rate and portable air purifier effectiveness were highly particle size-dependent. Filtration was found to be the dominant removal mechanism for submicrometer particles, whereas deposition could play a more important role in ultrafine particle removal. There was reasonable agreement between measured and modeled effectiveness with size-resolved slopes ranging from 1.11±0.06 to 1.25±0.07 (mean±SE), except for particles <35 nm. Sr was found to be a robust measure of indoor exposure to outdoor PM, and temperature was its significant predictor. Seasonal effect of temperature was much more dominant when compared to long-term effect on Sr, which differed in the whole population and the subpopulation of naturally ventilated homes. However, long-term temperature effect was small, with maximum of <10% for summer Sr compared to the past. Findings from the studies improved characterization of indoor PM exposure. The study design and methods can be used in the future to better understand exposure scenarios and their correlation to health effects in other homes or populations.

Advances in technologies associated with hydraulic fracturing and horizontal drilling in the first decade of this century have enabled a massive energy transformation in the United States. For the first time, carbon emissions in the U.S. have decreased steadily while economic growth has increased, largely because of the switch from coal to natural gas made possible by hydraulic fracturing and horizontal drilling. Also because of hydraulic fracturing, the U.S. is now the worldâs largest producer of oil and natural gas. The rapidity with which the nation experienced these changes saw communities grappling with oil and gas operations on a scale many had never experienced, bringing lucrative economic opportunities as well as challenges, especially to local and rural transportation infrastructure. Tools and methodologies are needed to assist communities, and newly emerging tools need data-driven analyses of their utility. This work represents the first comprehensive national survey of state regulators on the effectiveness of FracFocus, a tool developed by regulators to address chemical disclosure in hydraulic fracturing operations. The study provided needed visibility to the (often novel) ways states were using FracFocus to augment state regulatory programs with important potential for sharing valuable approaches between states. Important data and information emerging from the FracFocus study was then leveraged to develop a methodological approach for local planners addressing impacts from oil and gas development. With a focus on local transportation infrastructure, the methods developed were applied in a case study to the Tuscaloosa Marine Shale Oil Play in Mississippi, and included the views of local operators, a perspective largely missing from the literature. Finally, this work provides a legal and policy framework for local planners to better understand potential approaches and challenges to maintaining transportation infrastructure in the face of large scale hydraulic fracturing. Local communities have met with significant obstacles when attempting to regulate oil and gas development from an environmental or policy perspective, but local regulations tailored to address infrastructure impacts are more likely to be successful.

The purpose of my study was to collect data on managed cat (Felis catus) colonies located in two Miami-Dade County, Florida, parks, in order to test the following assertions put forward by proponents of the colonies: 1) Managed cat colonies will decline in size over time and 2) The territorial behavior of cats living in established cat colonies will prevent additional cats from joining. I collected observational and photographic capture-recapture data in order to track colony population dynamics. Behavioral data were also collected in order to understand the role that cat behavior plays in influencing colony population dynamics. My results do not support the assertion that colonies will decline over time. Instead, my findings demonstrate that the establishment of colonies on public lands encourages dumping of cats and creates an attractive nuisance. Furthermore, my behavioral analysis suggests that territorial behavior does not play a role in excluding new cats.