The objective of this study was to evaluate galvanic corrosion potential under various pH conditions, buffering capacities, and corrosion inhibitors including zinc orthophosphate (ZOP) and orthophosphate (OP). Bench-scale dump-and-fill experiments evaluated metals release from a lead and copper couple under stagnant conditions. Key findings from this study were that increasing DIC from 3 to 7 or 17 mg CaCO3/L significantly reduced lead release with or without corrosion inhibitor; however, the lowest lead concentrations were observed in water conditions with corrosion inhibitor addition. However, addition of 20 mg PO4/L as OP exacerbated lead release in some cases; though dissolved lead release was always below 28 µg/L, particulate lead was as much as 4 times greater compared to no corrosion inhibitor. Overall, this study demonstrated the potential of high dose ZOP and OP for lead corrosion control in drinking water, however, overdosing OP can lead to exacerbated particulate concentrations.

In the northern Gulf of Mexico, hypoxia occurs annually during the summer on the Texas-Louisiana shelf. This study examines the distribution of particulate and dissolved components relative to hydrography, to better understand the processes controlling the development of hypoxia. Particulate matter on the Texas-Louisiana Shelf has three major sources – river plumes, primary production, and resuspended sediments. The sources and processes controlling distribution and transport of particles are investigated using optical proxies (backscattering, chlorophyll fluorescence, Colored Dissolved Organic Matter fluorescence (CDOM)), temperature, salinity, dissolved oxygen (DO), and in-situ sampling during June and August 2011 cruises of the Mechanisms Controlling Hypoxia program (hypoxia.tamu.edu). Discrete samples of particulate matter (PM) and particulate organic carbon (POC) concentration were obtained for analysis and calibration of optical instruments interfaced with a profiling CTD, a towed undulating CTD (Acrobat), and the ship’s flow-through system along the shelf from south of Galveston, Texas, to east of the Mississippi delta. The results of this study support a previously hypothesized concept of three primary areas of organic and inorganic particle composition and processes that dominate those areas – river-dominated water, highly productive surface waters, and clear, nutrient-poor low-productivity surface waters. The distribution and bulk composition of particulate matter in the northern Gulf of Mexico, plus the distribution of chlorophyll fluorescence and CDOM suggest that subpycnocline primary production plays a role in determining oxygen concentration in subpycnocline waters away from the river-dominated water.

In South Africa one of the strongest influences on domestic indoor air quality is the type of energy used for heating, cooking and other household purposes. Emissions from fuel combustion, along with housing factors, can result in respiratory infections, a leading cause of death in the country. In this study I examine the relationships between energy types, patterns of use, housing conditions such as improper ventilation and overcrowding, indoor air quality and respiratory health in poorer communities of Msunduzi Municipality, South Africa. These variables were examined using an ecohealth perspective through the integration of data concerning individual time-activity budgets, housing materials and structure, energy sources used for heating, cooking and lighting, respiratory symptoms and continuous real time monitoring of indoor air pollutants (particulate matter (PM), carbon dioxide (CO2), carbon monoxide (CO) and sulphur dioxide (SO2)). A total of 20 dwellings, displaying large variability in housing structure and energy patterns, were sampled for 24 hours (hr) over a period of 60 days. The mean 24-hr average indoor concentrations measured were as follows: PM2.5= 16 ± 11 µg/m3, PM10= 78 ± 46 µg/m3, CO= 5 ± 6 ppm and SO2= 0.18 ± 0.27 ppm. Mean indoor concentrations measured were significantly greater than mean outdoor concentrations (p<0.0001 (PM2.5), p=0.017 (PM10), p<0.0001 (CO), p<0.0001 (SO2)). Although PM concentrations increased with the use of increasingly inefficient-burning fuel types (gas < paraffin < wood), no significant differences in the means were found across these fuel types. It is thought that the high degree of variability among dwellings and the small sample size in this study obscured any statistically significant relationships. No significant differences in mean concentrations were found across different housing types either. Indoor exposures were, on average, highest among very young children (ages 0-5) and elders (ages 51+). All age groups reported experiencing high levels of respiratory symptoms, with the elder group (ages 51+) reporting the highest percentages for each symptom. This study will be used to inform local governments and NGOs of local indoor air pollution and exposure risks, so that policy and resources can be allocated accordingly to improve physical environments. / Thesis (Master, Environmental Studies) -- Queen's University, 2007-09-27 08:52:05.443

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This work is primarily comprised of five self-contained papers. Three papers are applications oriented. A common element in the first three papers is that micro-perforated panels (MPP), the permeable membranes in diesel particulate filters, and a source impedance are all modeled as a transfer impedance. The first paper deals with enhancing the performance of micro-perforated panels by partitioning the backing cavity. Several different backing schemes are considered which enhance the performance without increasing the total volume of the MPP and backing. In the second paper, a finite element modeling approach is used to model diesel particulate filters below and above the plane wave cutoff frequency. The filter itself is modeled using a symmetric finite element model and results are compared to plane wave theory. After the transfer matrix of the filters is known, it is used in three-dimensional finite and boundary element models. The third paper is a tutorial that shows how a source impedance can be modeled using transfer impedance approaches in finite element analysis. The approach used is useful for better understanding the resonance effects caused by pipes upstream and downstream of the exhaust. The fourth paper examines the best practice for the two-load transmission loss measurement. This method was integral to obtaining the measurements for validating the diesel particulate filter models. The fifth paper proposes transmission and insertion loss metrics for multi-inlet mufflers. It is shown that the transmission loss depends on the amplitude and phase relationship between sources (at the inlets) whereas insertion loss depends on both the source strength and impedance for each inlet.

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Motivation: The investigation of agricultural respiratory hazards has lagged behind the investigation of hazards in mining and other heavy industries. Relatively few epidemiological data are available addressing pulmonary infections in the context of the agricultural work environment, especially for the South African population. Poultry house dust was generally considered nuisance or inert, meaning it has little adverse effect on human lungs. New research shows that because poultry house dust is largely organic and contain bacteria and other bioactive substances, it cannot be considered inert. Several published research manuscripts document that the legal and recommended exposure limits for the toxic substances found in the agricultural environment are to high for concentrated animal feeding operations (CAFO's). In CAFO's there is a mixture of biologically active agents that can work synergistic to produce respiratory and systemic effects at much lower levels. Most of the current legal exposure limits used in South Africa are adopted from international limits and guidelines. Because of the influence of geography, climate and degree of industrialisation on the agricultural air quality, the relevance of the foreign exposure limits is questionable. Aim: To determine if there is a correlation between occupational exposure to poultry farm dust and the lung function of poultry farm workers in the Potchefstroom district, South Africa. Also to determine if the current legal exposure limits used for ammonia and particulate matter (PM) in South Africa, offer adequate worker protection for poultry farm workers exposed to biologically active dust. Methodology: This was an observational, cross-sectional pilot study. A target population of fifty contract workers concerned with the removal and disposal of poultry manure were identified in the Potchefstroom district and a random sample of nineteen was drawn for participation in this study. Exposure to total and respirable dust were determined by means of personal sampling for the full duration of the time averaging period (8-hour TWA). Area monitoring for ammonia and bio-aerosols were done in poultry houses in three specific demarcated areas around Potchefstroom, and weather conditions were taken into account. Lung function tests (spirometry) were conducted before and after each work shift. Interviewer administered questionnaires were used to assess occupational and exposure histories and to detect symptoms of organic dust exposure. Results and conclusions: The mean total- and respirable dust concentrations complied with the legal limits of OSHA, NlOSH and the Regulations for hazardous chemical substances of 1995. However, fifty five percent of the measured total dust concentrations and all of the respirable dust measurements exceeded Donham's recommended values for human health. The spirometric values of the subjects were normal; there was no statistical difference between the mean baseline FEV1/FVC and the mean predicted FEV1/FVC. Results also show no statistically significant cross shift changes in any of the measured variables and there is no significant correlation of the measured dust concentrations to any of the spirometric measurements. It can be concluded that occupational exposure to ammonia, particulate matter and micro-organisms on poultry farms in the Potchefsroom district, South Africa, do not have any adverse effects on the workers' lung function and the workers are adequately protected in the short term, by the legal limits that are currently used in South Africa. / Thesis (M.Sc. (Occupational Hygiene))--North-West University, Potchefstroom Campus, 2006.

Aerosol emissions from diesel combustion and other activities in rail yards can affect the health of urban populations. Fine particulate (PM[subscript 2.5]) concentrations near the Inman and Tilford rail yards in Atlanta, Georgia, are the highest measured in the state. The rail yard complex is surrounded by homes, schools, businesses and other industries. The impact of the aerosol emissions from these rail yards on local concentrations of PM[subscript 2.5] was quantified. Specifically, black carbon and PM[subscript 2.5] fuel-based emission factors from the rail yards were estimated by carbon balance using high time-resolution monitoring, a BC and PM[subscript 2.5] emissions inventory was estimated and dispersion modeling was applied to assess the impact of the rail yard activities on local air quality and the cost and benefits of upgrading locomotive engines with cleaner technologies was assessed. Further, baseline information that will allow a later evaluation of the improvement of local air quality as locomotives operating in the rail yards are upgraded was generated, and a composition profile of the rail yard aerosols was developed using chemical speciation techniques. These results found that activities from locomotives in the Inman and Tilford Rail yards lead to and an average emission factor of 6.0 ± 0.5 g of PM[subscript 2.5] per gallon of fuel and are responsible for increases in annual average concentrations of approximately 1.3 µg/m³ of PM[subscript 2.5] as far as 1 km from the perimeter of the rail yard complex. Approximately 11.7 tons of BC and 26 tons of PM[subscript 2.5] per year were emitted from the rail yards in 2011. The rail yards were found to be important sources of hydrocarbon-like organic aerosols (HOA) and black carbon from fuel (BCf). Upgrading the engines at the rail yards would decrease PM[subscript 2.5] emissions by about 9 t/year, reducing PM[subscript 2.5] concentrations around 0.5±0.1 µg/m³ as far as 1 km from the perimeter of the rail yard complex and producing monetized health benefits of approximately 24 million dollars per year.