The lungs represent one of the earliest interfaces for pathogens and noxious stimuli to interact with the body. As such, careful maintenance of the permeability barrier is vital in providing homeostasis within the lung. Essential to maintaining this barrier is the tight junction, which primarily acts as a paracellular seal and regulator of ionic transport, but also contributes to establishing cell polarity, cell-to-cell integrity, and regulating cell proliferation and differentiation. The loss of these tight junctions has been documented to result in alterations in inflammation, and ultimately the development of many respiratory disorders such as COPD, Asthma, ARDS, and pulmonary fibrosis. One critical contributor that creates this permeability barrier is the tight junctional protein Claudin. While studies have begun to elucidate the various functions and roles of various Claudins, our understanding is still limited. To initially investigate these proteins, we looked at both temporal and spatial expression patterns for family members during development. A consistent pattern was demonstrated in mRNA expression for the majority of Claudin members. In general, Claudin expression underwent rapid increase during time periods that correlate with the pseudoglanduar/canalicular periods. One notable exception was Claudin 6 (Cldn6), which demonstrated decreasing levels of mRNA expression throughout gestation. We also sought to understand expression dynamics during the addition of maternal secondhand smoke (SHS) which resulted in an almost universal decrease in Claudin proteins. To more fully explore expression mechanisms that affect Claudin-6 (Cldn6), we exposed pulmonary alveolar type II (A549) cells to cigarette smoke extract (CSE) and found that it transcriptionally regulated Cldn6 expression. Using a luciferase reporter, we determined that transcription was negatively regulated at multiple promoter response elements by CSE, and transcription was equally hindered by hypoxic conditions. These findings identified Cldn6 as a potential target of SHS and other respiratory irritants such as diesel particulate matter (DPM). We next sought to assess whether an increase in Cldn6 was sufficient to provide a protective advantage against harmful exogenous exposure. To test this, we utilized a doxycycline induced Cldn6 over-expressing mouse, and subjected it to SHS for 30 days to stimulate an inflammatory state. Our findings demonstrated that Cldn6 transgenic animals have decreased inflammation as evidence by decreased total cell infiltration into the airways, decreased polymorphonuclocyte (PMNs) extravasation, total protein in bronchoalveolar lavage fluid (BALF), and decreased cytokine secretion. Anti-inflammatory advantages were also discovered during experiments involving acute exposure to DPM. In both cases, while stimulation of transgenic mice with SHS or DPM diminished Cldn6 expression, anti-inflammatory evidence emerged suggesting that genetic up-regulation of Cldn6 likely causes the recruitment of other tight junctional components during an organism's response to environmental assault.

Urban health problems and visibility degradation problems are associated with particulate matter in the air, especially PM10 and PM25 (particles with aerodynamic diameter less than 10 j.tm and 2.5 jsm, respectively). The aim of this study was to investigate the characteristics and sources of PM25 and PM20 aerosols in Brisbane. This study collected aerosol samples over a period of two and a half years at five sites around Brisbane. Source samples of soil dusts, road-side dusts and sea salt were also collected and analysed to provide information on source emission composition. The aerosol samples were analysed by a wide range of techniques, including Ion Beam Analysis and Scanning Electron Microscopy, for their chemical composition and particle size distribution. Some methodologies have been specifically developed in this study. The results presented here show that the chemical composition of PM20 aerosols in Brisbane varies largely with particle size and locations. The chemical composition of the samples are generally related to the land use near the monitoring sites. On average, the major components in the PM10 aerosol samples at five sites in Brisbane were identified as: crustal matter (27% by mass), organic matter (16%), sea salt (12%), soot (11%), and ammonium sulphate (7%). Among the Australian studies, in general, the results show that the composition of the PM25 aerosol samples collected at the Griffith University site (Brisbane) is closest to those of the New South Wales samples. The samples from Melbourne and Perth are generally richer in industry-and vehicle-related species. The major components of the PM25 aerosols at the GU site were identified as: organic matter (27% by mass), elemental carbon (23%), ammonium sulphate (14%), sea salt (9%) and crustal matter (6%). The results show that contribution of emission sources also has large particle size, temporal and spatial variations. Based on the results of source apportionment from the chemical mass balance method, the major contributors of PM20 aerosol mass in samples collected at five sites in Brisbane were found to include: soiL/road-side dusts (25% by mass, results of analysis also indicate a higher contribution from road-side dusts than from soil dusts), motor vehicle exhausts (13%, more than 80% of which are from diesel trucks/buses), elemental carbon and secondary products (around 15%), sea salt (12%), Ca/Ti-rich compounds from cement plant and mineral processing industries (11%), and biomass burning and bioaerosols (7%). On average, the PM25 aerosol mass at the Griffith University (GU) site was found to have contributions mainly from sources related to combustion. These sources include elemental carbon (24% by mass), secondary organics (21%), biomass burning (15%) and secondary sulphate (14%). Although motor vehicle exhausts contribute directly to only 6% of the PM25 aerosol mass at the GU site, their actual contribution could be substantial because most of the elemental carbon and secondary products are related to motor vehcile exhausts. On average, the results show that the visibility degradation problems in Brisbane are worse in winter/autumn than in summer. Soot and sulphate particles are the main visibility degrading species. In terms of visibility degrading sources, the main contributors are (excluding the contribution of NO2 gas): motor vehicles (up to 50%, including the secondary products), secondary sulphates (17%) and biomass burning (10%). In general, emission sources which contribute more to the fine particle fraction, and to gaseous pollutants, are most responsible for the aerosol associated health problems and visibility degradation problems. In Brisbane, these sources include motor vehicle exhausts, soil dusts, biomass burning and industrial dust.

Experimental work at the 1982 Dry Deposition Intercomparison Experiment (DDIEx) involved the use of optical particle counters for covariance estimates of dry deposition velocities of accumulation mode aerosols. Meteorological and particle flux observations are presented. Deposition velocity estimates exhibit scatter about zero. A formulation of the standard error of the deposition velocity estimator is derived and examined. Using this formulation, the observed deposition velocities are shown to be marginally significant. Using a case study, the correlation coefficient is examined and presented as an important statistic to the work. Humidity effects on the measurements are briefly examined. Recommendations are made for improvements in the instrumentation. / Graduation date: 1985

The European emission standard is an EU directive which describes what emission limits car manufactures are required to meet. In order to meet these requirements car manufacturers use different techniques and components. In a modern diesel automobile a Diesel Particulate Filter (DPF) is used to gather soot from the exhausts. As soot accumulates in the DPF, the back pressure increases and the capability to hold more soot decreases. Therefore the DPF continuously needs to get rid of the stored soot. The soot is removed through a process called regeneration. In order to optimize when to perform regeneration, it is vital to know the amount of soot in the filter. A method for estimating the soot mass in a DPF using a radio frequency-based sensor has been developed. The sensor that has been studied is the Accusolve soot sensor from General Electric. A parameter study has been performed to evaluate the parameters that affects the sensor’s output. Parameters that have been studied include positioning of the sensor, temperature in the DPF, flow rate through the DPF and distribution of soot in the DPF. Different models for estimation of soot mass in the DPF has been developed and analyzed. An uncertainty caused by removing the coaxial cable connectors when weighing the DPF has been identified and methods for minimizing this uncertainty has been presented. Results show that the sensor output is sensitive to temperature, soot distribution and position, and also show some sensitivity to the flow rate. An ARX model, with only one state, is proposed to estimate the soot mass in the DPF, since it gives the best prediction of soot mass and showed good resistance to bias errors and noise in all the input signals.

This thesis concerns various aspects of the influence of atmospheric particulate matter on the terrestrial system. In Part I, the radiative influence of particulate matter on the production of crops is explored using the CERES crop model. It is known that the presence of aerosols in the atmosphere simultaneously reduces the amount of sunlight reaching the surface and increases the fraction of that light which is diffuse. Reduction of the total amount of sunlight tends to slow the rate of photosynthesis occurring in plants while increasing the fraction which is diffuse tends to increase the net rate of photosynthesis by more evenly distributing sunlight throughout all layers of a plant canopy. The CERES crop model was modified to estimate the influence of both a reduction in total sunlight and an increase in the diffuse fraction. Model simulations were performed for rice, maize and wheat at a variety of locations and found the likely influence of aerosols on crop production to be a 0-10% reduction in yield compared to the base case. In Part II, the concentration and size distribution of water-insoluble aerosols (WIA) is explored. It has been well-established that atmospheric particulate matter influences the planetary radiation budget both directly and indirectly. The magnitude of these influences is related to particle solubility. A new technique was developed to provide these measurements in real-time. This instrumentation was evaluated in a laboratory setting and implemented into several field studies. Results from these sampling campaigns indicate that in areas heavily influenced by motor vehicle traffic, the WIA concentration is dominated by particulate soot. Many episodes of high levels of crustal dust were also observed. At these times, the WIA size distribution shifted toward larger sizes in a characteristic manner. This suggests that this method is useful for detecting insoluble mineral aerosols as well as particulate soot and that examination of the WIA size-distribution may provide a basis to distinguish between the two.

Water samples were collected along salinity gradients during different seasons from three estuaries (Tseng-Wen, Gao-Ping, Er-Ren) and coasts in/off southwestern Taiwan. In order to assess the partitioning of trace metals between solution and particle, the concentrations of dissolve and particulate trace metals (Cd, Cu, Ni, Pb) along with their chemical affinity fractions, were determined. This study investigated the variations in distribution and partitioning of the different metals in estuarine waters, and examined the effects of oxides and particulate organic matter on the partitioning of trace metals in waters from different estuaries. Fractionation of dissolved trace metal species was based on ion exchange (Chelex-100 and AG MP-1 resins) separation techniques. The fractions obtained were operationally defined as labile (Chelex), organic (AG MP-1) and inert. Particles were extracted to three phases (surface adsorbed phases, Fe¡VMn oxide/organic phases and refractory phases) using sequential extraction techniques. Seasonally variable distributions of dissolved trace metals were found in the Tseng-Wen estuary. The behavior of trace metals was mainly influenced by anthropogenic input during the dry season in the upper Tseng-Wen estuary, while mixing processes controlled the distribution of trace metals during the wet season. The dilution effect was a major factor in the metal distribution in the Gao-Ping estuary due to high river discharge. The higher concentration of metals in the Er-Ren estuary, in contrast to other estuaries indicated that the Er-Ren estuary has serious pollution concerns. According to the results of particulate metal fractions obtained, Cd and Pb existed predominantly in the surface adsorbed phase. The speciation and spatial distribution of Cd were similar to those of Mn, indicating that the formation of authigenic Mn oxides affected the distribution of Cd in estuaries. The percentage of oxide /organic phase for Cu accounted for 25% of total particulate Cu, but dose not correlate well with particulate organic carbon, implying that organic carbon is not the only factor controlling particulate Cu distribution. Ni was present mainly in lattice phase, except in the Er-Ren estuary where anthropogenic Ni loading was high. In the Tseng-Wen and Gao-Ping estuaries, the percentages of lattice phase of all metals determined in this study during the wet season were higher than those during the dry season. These seasonal variations are probably resulted from different flushing times in dry/wet seasons, which control the extent of geochemical processes for trace elements.

Water, suspended particle and sediment samples from Gao-ping coastal water column were collected and measured to determine the spatial and temporal distributions of polycyclic aromatic hydrocarbons (PAHs) during August 2010 and June 2011. In addition, principal component analysis (PCA) and hierarchical the cluster analysis (HCA) were performed with chemical fingerprinting to understand the possible sources of PAHs in Gao-ping coast. The correlations between PAHs and several factors such as salinity, temperature and organic carbon were also discussed in the present study. The total PAH concentrations (dissolved and particulate phase) at four sampling campaigns ranged from 2.09 to 45 ng/L. Concentrations of dissolved PAHs ranged from 2.0 to 39 ng/L and the highest average concentrations were found in November 2010 (10.0 ¡Ó 9.90 ng/L). The particulate PAHs ranged from 0.13 to 40 ng/L and the maximum concentration was found in the estuary in August 2010. The total PAH concentrations of sediment ranged from 125-648 ng/g, which were lower than the Effect Range Low (ERL) and Threshold Effect Level (TEL) values, suggesting that few adverse ecological effects would arise from the PAHs in Gao-ping canyon. Results from chemical fingerprinting, PCA and HCA indicate that PAHs in this area were from complex sources such as combustion, petroleum, diagenesis or biogenic sources. Sources of PAHs in dissolved phase were mainly from petrogenic and mixed sources, while particulate PAHs were mainly from a mixed source. However, sources of PAHs in November 2010 and February 2011 were mostly from mixed combustion, suggesting that the PAH concentrations in particulate phase might be affected by atmospheric transport. The results showed that perylene in Gao-ping coast and canyon was mainly from the biogenic source. A significant correlaction was found in PAH fingerprinting between the esturine particles and sediment, indicating that the sediments in Gao-ping canyon might mainly come from Gao-ping River. Correlation analysis showed a significant positive correlation between concentrations of suspended particle and PAHs, while a negative correlation was found between PAH concentrations and temperature. In addition, organic carbon showed a significant correlation with PAHs in sediment samples. The partition coefficients (Koc) values of PAHs were higher than the values from other literatures, suggesting that it might be attributed to soot carbon.

The Tapered Element Oscillating Microbalance (TEOM) sampler is an EPA approved Federal Equivalent Method Sampler for measuring PM10 concentrations. The Center for Agricultural Air Quality Engineering and Science (CAAQES) owns two Rupprecht and Patashnick (R&P) Series1400a monitors. The R&P Series 1400a monitor uses the TEOM method to measure particulate matter (PM) concentrations and was approved by EPA in 1990 as an automated equivalent method PM10 sampler. Since its approval, many state air pollution regulatory agencies (SAPRAs) have located R&P Series 1400a monitors at community-oriented monitoring sites. Some SAPRAs have even located TEOM samplers at the property line of major sources to determine if the source is meeting its permit requirements for PMc emissions. This thesis presents the results of PM10 and TSP concentrations measured with TEOM and low-volume gravimetric samplers at two Texas cattle feedlots. The purpose of this research was to compare the performance of the R&P Series 1400a monitor to the low-volume gravimetric sampler when sampling PM from a feedlot. Furthermore, this research was conducted to avoid the inappropriate regulation of cattle feedlots that may occur in the future as a consequence of the TEOM sampler being used to measure PMc emissions. The results of this research demonstrate that relationship between the R&P Series 1400a monitor and the low-volume gravimetric sampler is linear. In general, it was observed that the TEOM sampler measured higher PM10 and TSP concentrations than the low-volume gravimetric sampler when sampling downwind from a cattle feedlot. The opposite results were observed when sampling was conducted upwind from the feedlot. The collected data demonstrates that the concentration difference between the two sampling methods is linearly dependent with the concentration intensity for the upwind sampling locations. This trend was shown to be statistically significant. Another linear relationship was observed between the concentration difference and the particle size (mass median diameter and geometric standard deviation) of the sampled dust. Although this trend was not statistically significant, it is believed that additional downwind concentration measurements would validate this relationship.

Poor regional air quality in some states across the US cotton belt has resulted in increased pressure on agricultural sources of particulate matter (PM) from air pollution regulators. Moreover, inaccurate emission factors used in the calculation of annual emissions inventories led to the identification of cotton harvesting as a significant source of PM10 in California and Arizona. As a result, cotton growers in these states are now required to obtain air quality permits and submit management practice plans detailing the actions taken by the producer to reduce fugitive PM emissions from field operations. The objective of this work was to develop accurate PM emission factors for cotton harvesting in terms of total suspended particulate (TSP), PM10, and PM2.5. Two protocols were developed and used to develop PM emission factors from cotton harvesting operations on three farms in Texas during 2006 and 2007. Protocol one utilized TSP concentrations measured downwind of harvesting operations with meteorological data measured onsite in a dispersion model to back-calculate TSP emission flux values. Flux values, determined with the regulatory dispersion models ISCST3 and AERMOD, were converted to emission factors and corrected with results from particle size distribution (PSD) analyses to report emission factors in terms of PM10 and PM2.5. Emission factors were developed for two-row (John Deere 9910) and sixrow (John Deere 9996) cotton pickers with protocol one. The uncertainty associated with the emission factors developed through protocol one resulted in no significant difference between the emission factors for the two machines. Under the second protocol, emission concentrations were measured onboard the six-row cotton picker as the machine harvested cotton. PM10 and PM2.5 emission factors were developed from TSP emission concentration measurements converted to emission rates using the results of PSD analysis. The total TSP, PM10, and PM2.5 emission factors resulting from the source measurement protocol are 1.64 ± 0.37, 0.55 ± 0.12, and 1.58E- 03 ± 4.5E-04 kg/ha, respectively. These emission factors contain the lowest uncertainty and highest level of precision of any cotton harvesting PM emission factors ever developed. Thus, the emission factors developed through the source sampling protocol are recommended for regulatory use.

Previous studies have demonstrated that EPA approved federal reference method (FRM) samplers can substantially misrepresent the fractions of particles being emitted from agricultural operations due to the relationship between the performance characteristics of these samplers and existing ambient conditions. Controlled testing in a wind tunnel is needed to obtain a clearer understanding and quantification of the performance shifts of these samplers under varying aerosol concentrations, wind speeds and dust types. In this study, sampler performance was tested in a controlled environment wind tunnel meeting EPA requirements for particulate matter (PM) sampler evaluation. The samplers evaluated included two low-volume PM10 and Total Suspended Particulate (TSP) pre-separators. The masses and particle size distributions (PSDs) obtained from the filters of tested samplers were compared to those of a collocated isokinetic sampler. Sampler performance was documented using two parameters: cut-point (d_50) and slope. The cut-point is the particle diameter corresponding to 50% collection efficiency of the pre-separator while the slope is the ratio of particle sizes corresponding to cumulative collection efficiencies of 84.1% and 50% (d_84.1/d_50) or 50% and 15.9% (d_50/d_15.9) or the square root of 84.1% and 15.9% (d_84.1/d_ 15.9). The test variables included three levels of wind speeds (2-, 8-, and 24-km/h), five aerosol concentrations varying from 150 to 1,500 mu g/m3 and three aerosols with different PSDs (ultrafine Arizona Road Dust (ARD), fine ARD and cornstarch). No differences were detected between the performance of the flat and louvered FRM PM10 samplers (a = 0.05). The mean cut-point of both the PM10 samplers was 12.23 mu m while the mean slope was 2.46. The mean cut-point and slope values were statistically different from the upper limit of EPA-specified performance criteria of 10.5 mu m for the cut-point and 1.6 for the slope. The PM10 samplers over-sampled cornstarch but under-sampled ultrafine and fine ARD. The performance of the dome-top TSP sampler was close to the isokinetic sampler, and thus it can be used as a reference sampler in field sampling campaigns to determine true PM concentrations. There were large variations in the performance of the cone-top TSP samplers as compared to the isokinetic sampler. Dust type and wind speed along with their interaction had an impact on sampler performance. Cut-points of PM10 samplers were found to increase with increasing wind speeds. Aerosol concentration did not impact the cut-points and slopes of the tested samplers even though their interaction with dust types and wind speeds had an impact on sampler performance.