Electrostatic Dust Collectors (EDCs) are a passive sampling method that has not yet been fully validated. Our first study investigated the effect of EDC mailing and EDC deployment in front of and away from heated ventilation on endotoxin concentrations. Endotoxin sampling efficiency of heated and unheated EDC cloths was evaluated. EDCs express mailed cross-country yielded no significant changes in endotoxin concentrations when dust-only samples were compared to high quality control (QC) spiked-EDCs (p=0.21) and low QC spiked-EDCs (p=0.16). EDCs were deployed in 20 apartments with one EDC placed in front of the univent heater and another EDC placed on a built-in bookshelf. Endotoxin concentrations were significantly different (p=0.049) indicating that EDC placement impacts endotoxin sampling. Heated and unheated EDCs were deployed for 7 days in farm homes. There was a significant difference between endotoxin concentrations (p=0.027). The electrostatic charge of 12 heated and 12 unheated EDC cloths were significantly different (p=0.009). These studies suggest that heating cloths may diminish their electrostatic charge and endotoxin sampling capabilities. The EDC sampling time needed to achieve detectable and reproducible loading for bioaerosols has not been systematically evaluated. In our second study, EDCs were deployed in 15 Iowa farm homes for 7-, 14-, and 28-day sampling periods to determine if endotoxin and allergens could be quantified and if loading rates were uniform (i.e. doubling from 7 to 14 days and 14 to 28 days and quadrupling from 7 to 28 days). Loadings between left and right paired EDC cloths were not significantly different and were highly correlated for endotoxin, total protein, and cat (Fel d1), dog (Can f1) and mouse (Mus m1) allergens (p<0.001). EDC endotoxin sampling had close agreement between paired samples (Pearson p=0.96, p<0.001). EDC endotoxin loading doubled from 7 to 14-day deployments but the loading rate decreased from 14 to 28 days of sampling with only a 1.38 fold increase. Allergen exposure assessment using EDCs was less satisfactory. Paired EDCs and daily Button aerosol samplers (BS) were used in our third study to concurrently sample endotoxin in 10 farm homes during 7 day periods in summer and winter. Winter sampling included an optical particle counter (OPC) for particulate size and number concentration data. OPC particulate matter (PM) data were divided into PM2.5 and PM10-2.5. Summer sampling yielded geometric mean and geometric standard deviation values of 0.82 EU/m3 (2.7) for inhalable aerosol BS and 737 EU/m2 (1.9) for EDCs. Winter values were 0.52 EU/m3 (3.1) for BS and 538 EU/m2 (3.0) for EDCs. Seven day endotoxin values of EDCs were significantly and highly correlated with the 7-day BS sampling averages (p=0.70; p<0.001). An Analysis of Variance indicated a 2.37-fold increase in EDC endotoxin concentrations for each unit increase of the ratio of PM2.5 to PM10-2.5. A 10-fold increase in BS endotoxin concentrations was associated with a 12.2-fold increase in EDC endotoxin concentrations. Our fourth study established QC protocols use of EDCs in large field studies. QCs were developed for endotoxin, peptidoglycan, and glucan for analysis alongside the Agricultural Lung Health study EDC samples. The coefficient of variation percentage (CV) for each QC was used to determine variability. For each QC, 20 EDC cloths were analyzed to establish an acceptable range (mean ± 3 standard deviations). Two QCs were established for endotoxin analysis. The high QCs were dust-spiked EDCs with a CV of 29.7%. The low QCs were spiked with E. coli standard and had a CV of 15.6%. One QC was established for peptidoglycan analysis using dust-spiked EDC extracts. Two glucan QCs were established using dust-spiked EDCs with a high CV (51.7%) and yeast-spiked EDCs with a CV of 26.0%. Endotoxin and glucan concentrations of AGLH EDC samples were found to be significantly correlated (p=0.71; p<0.0001). In conclusion, EDCs are an effective passive sampling method for endotoxin exposure assessment in farm homes.

I investigated the pollination ecology ofHesperidanthus suffrutescens, an endangered Utah shrub, as well as the effects that road dust and local plant density may have on successful reproduction. The breeding system study included four pollination treatments to determine the degree of self-compatibility. Flower visitors were collected and probable pollinators were identified. To determine the effects of road dust on reproduction, I measured dust deposition, plant size, and reproduction in plots of increasing distance from an unpaved road. I also measured dust effects on pollination success and stomatal conductance. I determined the number of individuals per plot and the relative isolation of individuals, and measured their reproductive success to determine any significant effects. Reproduction was measured as total fruit set per plant as well as estimates of total plant seeds and plant seed weight (mg). The results of the pollination treatments and the identity of pollinators are described in Chapter 2. Both autogamy and geitonogamy (selfing treatments) produced substantially and significantly fewer fruits, seeds, and seeds per fruit than xenogamy (outcrossing treatment). Additionally, outcrossed flowers produced significantly more fruits, seeds, and seeds per fruit than did open control flowers with no difference in mean seed weight. In total, 77 flower visitors were collected over the course of the study. Probable pollinators include severalAndrena,Halictus, andDialictusbees. The effects of road dust on the reproductive success ofH. suffrutescensare discussed in Chapter 3. Dust deposition decreased with increased distance from the road and was significantly correlated with decreased fruit set for plants of a given size. Other reproductive metrics showed the same negative patterns although not significantly. The results suggest that dust may disrupt pollination and affect the physiology of plants, resulting in decreased reproduction. Dust deposition did not decrease pollination success of dusted flowers but did negatively impact stomatal conductance of leaves. The main effects of patch size and relative isolation on reproductive success are discussed in Chapter 4. Both patch size and relative isolation had no significant impacts on reproductive success. Increased patch size did indicate negative patterns on reproductive metrics, although not significantly. Similarly, increased isolation indicated increased reproductive success, although not significantly.

Mineral dust both influences and is influenced by climate on many timescales, from seconds to epochs. Its complex interactions with the climate system are still being unraveled. For example, dust fluxes change in tandem with other records of past changes in climate, and dust source is often presumed to change as well, in response to shifts in climate conditions in source regions; changes in wind regimes; or changes in atmospheric transport pathways. In this work, I investigate dust records from the Southern Hemisphere from ice core and marine sediment core climate archives, looking at both flux and provenance in order elucidate the conditions that allowed for those particles to travel from source to sink. Using multiple radiogenic isotope systems as tracers (87Sr/86Sr, εNd(0), 206Pb/207Pb, and 208Pb/207Pb), I geochemically “fingerprint” of dust particles from Southern Hemisphere climate archives over the last glacial cycle. I compare the dust fingerprints to potential source areas (PSA’s) from across the Southern Hemisphere in order to identify the sources of dust found in the WAIS Divide and Taylor Glacier ice cores from West Antarctica, as well as from marine sediment core ELT39.75 in the Tasman Sea. I use endmember mixing theory to determine the relative contribution of different sources to the climate archives over time. In West Antarctica, I geochemically identify specific local volcanoes from Marie Byrd Land as significant particle contributors to the WAIS Divide ice core during the previous glacial period. In the Tasman Sea, I identify a specific region of southeastern Australia as primary the dust source over the past glacial cycle, with the source remaining constant across glacial-interglacial climate transitions. This clarifies that the “fingerprint” of Australian dust is relatively invariant over time and allows a single Australian signature to be used as an endmember for identifying dust provenance in climate archives downwind. I also identify the dust sources in the WAIS Divide during the Last Glacial Maximum and through the early deglacial, identifying southern South America as the predominant source during cold stages. WAIS Divide and Taylor Glacier dust records do not record dust source changes across millennial-scale climate events, suggesting that a) the source regions did not change, b) the transport pathways remained pinned, or c) the proxy is not sensitive to changes in these variables. Contributions from local volcanoes are also inferred from the WAIS dust record using mixing theory. In summary, I find that the radiogenic isotope fingerprint of dust samples from the archives analyzed show subtle or no changes in source over climate transitions, and therefore the strategy of dust particles as a tracer of past atmospheric circulation pathways should be approached cautiously.

Dust control is a very significant issue in underground coal mining. The benefits of reducing dust levels will be a lesser risk of lung disease to coal miners, improved working conditions and a reduced risk of dust explosions. Coal dust is commonly suppressed by water sprays but suppression efficiency is not high because dust tends to travel in the air flow round the water droplets rather than being captured by them. If water sprays are electrostatically charged, then a significant improvement in dust suppression efficiency may be achieved. Of the three principal droplet charging mechanisms, i.e. corona charging, induction charging and contact charging, corona charging is the most widely used in many industrial fields including dust suppression, However, it requires a high applied voltage, ranging from thousands to more than a hundred thousand volts, depending on the geometry of the charging equipment. Induction charging has been used in agricultural spraying since Law (1978) developed an embedded-electrode induction charging spraying nozzle. This nozzle provides a compact, inexpensively fabricated droplet charger and, reduces design requirements on size and output voltage (of the order of 1000 volts). It also reduces the potential for mechanical damage, misalignment and personnel hazard. In order to evaluate the effectiveness of dust suppression, either the charge on individual droplets or the charge-to-mass ratio of water sprays needs to be known. However, the parameters which control the charge applied to water and the charging rate have been unsolved theoretically for any charging mechanism. The existing theories for the induction-charged and air-atomising a liquid jet have been found to be inadequate. And there is no theory available for corona charging of the droplets produced with a pneumatic nozzle in order to predict the spray charge level or the spray charge-to-mass ratio. In view of this situation, mathematical models have been developed in this thesis for both the corona and induction charging mechanisms. During the development of the theories, it has been assumed that for corona charging, that the jet is disintegrated into droplets and the droplets are then charged; for induction charging, that the jet is first charged and the charged jet is then disintegrated into charged droplets. The Sauter mean diameter of the sprays, D32 , plays an important role in linking the individual droplet charge to the spray charge-to-mass ratio for both charging mechanisms. The developed theories are general models suitable for any liquid with both corona and induction charging. Theoretical calculations for the spray charge-to-mass ratio, individual droplet charge and the ratio of droplet charge to the Rayleigh charge limit have been presented for almost all of the influencing electrical and mechanical parameters such as applied voltage, air flowrate, liquid flowrate, liquid conductivity, liquid dielectric constant, nozzle dimensions, cylindrical electrode dimensions, and fluid parameters, for example, density, viscosity and surface tension. In the calculation for corona charging of droplets, the effect of the droplets on corona current and corona-onset voltage has been assessed for first time. The introduction of the Sauter mean diameter of the sprays, D32 , makes the assessment possible. Theoretical calculations for induction charging of liquid jets have shown that provided liquids have a conductivity value higher than the critical value, s = - 10 4 S/m, then they can be charged satisfactorily by the induction charging method. Among all of the influencing parameters, the electrical and mechanical parameters determine the charging rate and the water spray charge level. The suitability of employing these two charging mechanisms to dust suppression in coal mine has been evaluated based on the spray charge level, safety issues and the simplicity or otherwise of the equipment. The induction charging method was considered to have advantages over its corona charging counterpart, and has been chosen for charging the water sprays in the experiment program. Water has a conductivity of s = - 10 2 S/m, higher than the critical value, s = - 10 4 S/m. Based upon theoretical considerations, it is concluded that water is an appropriate liquid for corona charging, based on its dielectric constant, and for induction charging, based on its conductivity. In order to facilitate the testing of electrostatically charged water spray cloud parameters, a spray charger/collector was designed and constructed by others and a computerised data acquisition system has been employed. According to the theory developed for induction charging, the optimum length of the charging electrode has been analysed based upon the assumption that water jet is first charged and then the charged jet is disintegrated into charged droplets by the high pressure air. An experimental program examined the dependence of spray current upon four parameters: air flowrate, water flowrate, applied voltage and jet diameter. The experiments have shown that the induction-charged air-atomising nozzle used in the experiment is able to impart a significant charge into the water sprays. The spray charge-to-mass ratio calculated based upon the measured spray current demonstrates the same characteristics as predicted by theory: increasing with air flowrate, decreasing with water flowrate, increasing with applied voltage to a peak value then decreasing with further increase in the voltage, and increasing with jet diameter. A successful interpretation of an important phenomenon in the inductioncharged air-atomising a water jet, that spray charge-to-mass ratio and spray current increase with air pressure (or air flowrate) and decrease with increasing water flowrate, has been achieved based on the theories developed in this thesis. This phenomenon occurs because increasing air flowrate and/or decreasing water flowrate leads to a higher velocity of jet flowing through the induction electrode. However, when water flowrate becomes very small, a decrease in spray current with increasing air pressure (or flowrate) may be caused both by jet breakup inside the electrode and by contraction of the jet. In order to verify the theory, a preliminary comparison of experimental data with theoretical predictions employing a constant kic in the air-jet interaction coefficient a which was assumed to be 0.7 has shown a general agreement. However, the value of kic appears to be related to jet diameter, air/water mass ratio and applied voltage. An empirical equation for kic has then been formulated based on the experimental data for the spray charge-to-mass ratio. Finally a comparison of experimental results with theoretical predictions using the formulated kic shows an improved agreement. It is concluded that the induction-charged air-atomising nozzle has a potential application in dust suppression in coal mines, as the voltage required to charge water sprays is only 1000 ~ 1200 volts, and that the theory developed for induction charging of water sprays can be used to guide laboratory investigations and design processes for dust suppression and other industrial applications which might employ the electrostatic charging of liquid sprays.

The potential of atmospheric dust aerosols to modify the Earth's environment and climate has been recognized for some time. However, predicting the diverse impact of dust has several significant challenges. One is to quantify the complex spatial and temporal variability of dust burden in the atmosphere. Another is to quantify the fraction of dust originating from human-made sources. This thesis focuses on the spatiotemporal characterization of sources and dust outbreaks in Central and East Asia by integrating ground-based data, satellite multi-sensor observations, and modeling. A new regional dust modeling system capable of operating over a span of scales was developed. The modeling system consists of a dust module DuMo, which incorporates several dust emission schemes of different complexity, and the PSU/NCAR mesoscale model MM5, which offers a variety of physical parameterizations and flexible nesting capability. The modeling system was used to perform for the first time a comprehensive study of the timing, duration, and intensity of individual dust events in Central and East Asia. Determining the uncertainties caused by the choice of model physics, especially the boundary layer parameterization, and the dust production scheme was the focus of our study. Implications to assessments of the anthropogenic dust fraction in these regions were also addressed. Focusing on Spring 2001, an analysis of routine surface meteorological observations and satellite multi-sensor data was carried out in conjunction with modeling to determine the extent to which to this integrated data set can be used to characterize the spatiotemporal distribution of dust plumes at a range of temporal scales, addressing the active dust sources in China and Mongolia, mid-range transport and trans-Pacific, long-range transport of dust outbreaks on a case-by-case basis. This work demonstrates that adequate and consistent characterization of individual dust events is central to establishing a reliable climatology, ultimately leading to improved assessments of dust impacts on the environment and climate. This will also help to identify the appropriate temporal and spatial scales for adequate intercomparison between model results and observational data as well as for developing an integrated analysis methodology for dust studies.

This study collected relevant data of construction sites between January 1990 and December 2011 to estimate the emission factors of various construction projects for Kaohsiung City using Jhang¡¦s equations. The emission factors of various construction projects are as follows: about 0.121 kg/m2/month for reinforced concrete construction, about 0.141 kg/m2/month for steel constructed buildings, 0.228 kg/m2/month for road (tunnel) works, 0.126 kg/m2/month for bridge works, 0.101 tons/ha/month for regional construction projects, and 0.223 kg/m2/month for others. Based on these emission factors, the total fugitive dust emissions for 2,011 construction projects is estimated to be about 22,087.98 tons, and the exposure of per unit area to the fugitive dust pollution is approximately 11.98 ton/km2/month. The total fugitive dust emissions of 2,011 construction projects is estimated about 10528.14 tons (based on Kaohsiung City construction information database). According to the Department of Land, Kaohsiung City Government, Kaohsiung city is 27.8 kilometers from south to north, 10.4 kilometers from west to east, and the administrative area is 153.6029 square kilometers. The exposure of per unit area to the fugitive dust pollution is about 5.71 ton/km2/months.

Polycyclic aromatic hydrocarbons (PAHs) are widely distributed in the environment and are generated by many sources. Though the potential of PAH-rich mixtures to cause health effects has been known for almost a century, there are still unanswered questions about the levels of PAHs in the environment, the potential for human exposure to PAHs, the health effects associated with exposure, and how genetic susceptibility influences the extent of health effects in individuals. The first objective of this research was to quantify concentrations of PAHs in samples of settled house dust collected from homes in Azerbaijan, China, and Texas. The trends of PAH surface loadings and percentage of carcinogenic PAHs were China > Azerbaijan > Texas, indicating that the risk of health effects from exposure to PAHs in house dust is highest in the Chinese population and lowest in the Texas population. PAHs in China and Azerbaijan were derived mainly from combustion sources; Texas PAHs were derived from unburned fossil fuels such as petroleum. The second objective of this research was to investigate the effect of pregnane X receptor (PXR) on the genotoxicity of benzo[a]pyrene (BaP). BaP treatment resulted in significantly lower DNA adduct levels in PXR-transfected HepG2 cells than in parental HepG2 cells. Total GST enzymatic activity and mRNA levels of several metabolizing enyzmes were significantly higher in cells overexpressing PXR. These results suggest that PXR protects cells against DNA damage by PAHs such as BaP, possibly through a coordinated regulation of genes involved in xenobiotic metabolism. The third objective of this research was to investigate biomarkers of exposure in house mice (Mus musculus) exposed to PAH mixtures in situ. Mice and soil were collected near homes in Sumgayit and Khizi, Azerbaijan. Mean liver adduct levels were significantly higher in Khizi than in Sumgayit. Mean lung and kidney adduct levels were similar in the two regions. The DNA lesions detected may be a combination of environmentally-induced DNA adducts and naturally-occurring I-compounds. PAHs were present at background levels in soils from both Khizi and Sumgayit. It appears that health risks posed to rodents by soil-borne PAHs are low in these two areas.

A high-volume air sampler (PS-1) was used to measure the concentrations of polycyclic aromatic hydrocarbons (PAHs) in the atmosphere of Kaohsiung coast, PAHs diagnostic ratios,Hierarchical Cluster Analysis (HCA) and Principal Component Analysis (PCA) were employed to determine the potential sources of PAHs. The results show that the lowest concentrations of PAHs occurred in May (2.62 ngm-3), while the highest occurred in December (36.4 ngm-3). The nighttime concentrations of PAHs are higher than daytime with average night / day ratio of 1.65. The PAHs was more distributed in gas phase with proportions between 64.1 to 93.7 %. The 2, 3-Ring PAHs were mostly present in the gaseous phase (96.2 and 96.5 % respectively), 4-Ring also present dominantly in the gaseous phase (73.0 %), 5-Ring present mostly in the particle phase (80.2 %), 6, 7-Ring PAHs were mostly present in particulate phase (97.4 and 97.7 % respectively). During the Ghost Festiva and Asian dust storm events, atmospheric concentrations of PAHs and PAHs/TSP ratios were both found increased. It is found that gaseous and particulate PAHs correlate negatively with ambient temperature(r=-0.62, -0.57). Results from analyses of diagnostic ratios, HCA and PCA, the major sources of pollution include gasoline, diesel exhaust and industrial emission.

Mineral dust is ubiquitous in the atmosphere and represents a dominant type of particulate matter by mass. Despite its well-recognized importance, assessments of dust impacts on clouds and climate remain highly uncertain. This thesis addresses the role of dust as cloud condensation nuclei (CCN) and giant CCN (GCCN) with the goal of improving our understanding of dust-warm cloud interactions and their representation in climate models. We investigate the CCN-relevant properties of mineral dust samples representative of major regional dust sources experimentally in the laboratory conditions to determine their respective affinity to water. Based on the experimental exponent derived from the dependence of critical supersaturation with particle dry diameter, we determine the dominant physics of activation (i.e., adsorption activation theory (AT) or traditional Köhler theory (KT)) for dust particles from different global regions. Results from experimental measurements are used to support the development of a new parameterization of cloud droplet formation from dust CCN for climate models based on adsorption activation mechanism. The potential role of dust GCCN activating by AT within warm stratocumulus and convective clouds is also evaluated.

Thesis--Lund. / Includes bibliographical references (p. 221-228).