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Ultrafine particles (UFPs) are present in the ambient atmosphere and are generated from atmospheric gases, pollution sources, and combustion. Candles emit carbonaceous soot particles similar to UFPs present in the ambient atmosphere. With the exception of lead, airborne concentrations of candle emissions have not been shown capable of causing cancer or cardiopulmonary disease during normal use. The purpose of this research is to determine the occupational risk associated with candle emissions. Candle studies employ chambers to measure candle emission exposures and assess public health risk. Chambers used in previous studies did not match normal room conditions. They were affected by turbulence and high temperature, which affected particle distribution and constituent concentrations, while making it difficult to extrapolate the results. The chamber designed for this study sought to avoid the problems noted above. This study also employed a room constructed to closely simulate a normal work environment. Candle suppliers and users were surveyed to determine occupational candle use and settings. Scented, unscented, and church candles were measured in both ventilated and unventilated environments. A condensation nuclei counter was used to measure UFPs from candle emissions. Relative to previous chamber designs, results indicated a reduction in candle soot generation, no significant airborne concentrations of metals, and airborne concentrations of polycyclic aromatic hydrocarbons (PAHs), below occupational limits. Scented candles generated more soot than unscented candles. UFP studies have demonstrated only weak associations between ambient UFP exposures and cardiopulmonary disease. However, ambient UFP exposures were used as a benchmark for candle soot exposures. The lifetime average daily dose (LADD) was calculated from the candle soot measurement data and ambient UFP data. Candle soot generated inside the test room ranged from 5.73 x 109 to 1.86 x 1011 number of candle soot particles inhaled daily compared to the 3.25 x1011 to 2.45 x 1012 soot particles inhaled in the ambient environment. The calculated candle soot dose was nearly an order of magnitude less than the calculated ambient dose. The conclusion is that candle emissions do not pose a health risk under normal occupational use.

Surgical masks are intended to be used to prevent transmission of disease from a health care worker to a patient. Often times, they are relied upon by health care workers for their own protection. In light of recent developments regarding preparation for health care worker response to global infectious diseases such as H1N1 Influenza, health care workers may experience a false sense of security when wearing surgical masks. The goal of this study was to evaluate the filtration efficiency of a double strap tie-on surgical mask. The manufacturer asserts a >95% efficiency with a 0.1 um challenge aerosol under FDA testing procedures. The NIOSH Title 42 CFR Part 84 certification criteria call for testing at a rate of 85 lpm representing a human moderate to heavy work load breathing rate. Three sizes of monodispersed aerosols (polystyrene latex beads: 0.5 um, 1.0 um, 2.0 um) were used. The specific aims were to measure the collection efficiencies of this mask for the various particle sizes. Two tests were performed. In the first, masks were affixed to a dummy head and the edges of the mask were not sealed. In the second, the edges of the masks were sealed to the head using silicone sealant, so all penetration was through the filtering material of the mask. Differences in upstream and downstream particle concentrations were measured. Thus, penetration by leakage around the mask and through the filtering material was measured. The experimental set up involved passing the aerosol from the nebulizer through a diffusion dryer and Kr-85 charge equilibrator ensuring a dry charge neutralized aerosol cloud for detection by a LASAIR particle counter. The analysis revealed that the filtration efficiency for 0.5 um particles ranged from 3% to 43% for the unsealed masks and 42% to 51% for the sealed. For 1.0 um particles, the efficiency was 58% to 75% for unsealed and 71% to 84% for sealed masks. For 2.0 um, the efficiency was 58% to 79% for unsealed masks and 69% to 85% for the sealed masks. The data were statistically significant and indicated that surgical masks were associated with very low filtration efficiency. This suggests that they may be inadequate against airborne viruses and bacteria.

Hazards associated with air pollution motivate the search for technologies capable of monitoring individual exposure to gaseous pollutants and particulate matter (PM). A Low-cost Optical Particle Counter (OPC), costing less than 50 USD, is an example of such technologies. Currently, OPCs are widely used to measure the concentration of particle matter in ambient air. While these low-cost air quality sensors are widely available, the accuracy and precision of these devices is highly uncertain. Consequently, the purpose of this thesis is to present an analytical model of two generic, low-cost OPCs based on the Laws of Conservation of Mass, Momentum, and Energy. These models utilize Mie scattering theory and Computational Fluid Dynamics models to quantify uncertainty and accuracy in low-cost OPCs based first principles. Modeling results indicate that the measurement of forward-scattered light may dramatically increase the accuracy of low-cost OPCs. These results also indicate that careful attention must be placed on the design of sensor flow passages so as to most efficiently transport particles to the scattering volume where they may be detected. A combination of careful attention to photodetector placement in the forward scattering regime as well as efficient transport to the scattering volume may increase low-cost OPC accuracy by magnitudes of order.

The purpose of this project is to investigate and propose a system for condition monitoring and analysis of the hydraulic system of a forestry machine based on available on-board oil quality sensor data. The sample machine used was Scorpion King from Ponsse. This machine is equipped with an Icount PDR particle sensor from Parker. A two weeks long field test was conducted by Skogforsk. The data measured by the particle counter was collected, and breaks longer than five minutes were recorded as well as the reason for each break. The main results from the thesis are the relations between three factors: number of particles in the oil, machine operations, and machine breaks. The thesis also aims at proposing how the operator could use the Icount PDR data to manage the maintenance of the machine. / Syftet för detta projekt är att utreda och föreslå ett system för tillståndsövervakning och analys av en skogsmaskins hydraulsystem baserat på tillgängliga data från ombordmonterade partikelsensorer. Den maskin som studerats är Ponsse Scorpion King, som är utrustad med partikelsensorn Icount PDR från Parker. Data samlades in under en två veckor lång fälttest. Maskinoperationerna och mätdata från partikelräknaren samlades in, och orsakerna till avbrott längre än fem minuter loggades manuellt. Resultatet av detta examensarbete presenterar relationerna mellan tre faktorer: partikelantal hos hydrauloljan, maskinens verksamhet och de avbrott som inträffade. Denna avhandling avser också föreslå hur informationen från Icount PDR skall presenteras för operatören och hur förebyggande maskinunderhåll skall kunna planeras.

Control and analysis of protein aggregation is an increasing challenge to biopharmaceutical research and development. Therefore it is important to understand the interactions, causes and analysis of particles in order to control protein aggregation to enable successful biopharmaceutical formulations. This work investigates the role of different non-ionic surfactants on protein conformational stability, as assessed by HSDSC, and on protein size stability as assessed by Dynamic Light Scattering (DLS), HIAC and MFI. BSA and IgG2 were used as model proteins. Thermal unfolding experiments indicated a very weak surfactant-immunoglobulin IgG2 interaction, compared to much stronger interactions for the BSA surfactant systems. The DLS results showed that BSA and IgG2 with different surfactants and concentration produced different levels of particle size growth. The heat treatment and aging of samples in the presence of Tween 20, Tween 80, Brij 35 and Pluronic F-68 surfactants led to an increase in the populations of larger particles for BSA samples, whereas IgG2 systems did not notably aggregate under storage conditions MFI was shown to be more sensitive than HIAC technique for measuring sub-visible particles in protein surfactant systems. Heat treatment and storage stress showed a significant effect on BSA and IgG2 protein sub-visible particle size stability. This work has demonstrated that both proteins with different Tween 20, Tween 80, Brij 35 and Pluronic F-68 concentrations, have different level of conformational and size stability. Also aging samples and heating stress bears the potential to generate particles, but this depends on surfactant type. Poor predictive correlations between the analytical methods were determined.

Control and analysis of protein aggregation is an increasing challenge to biopharmaceutical research and development. Therefore it is important to understand the interactions, causes and analysis of particles in order to control protein aggregation to enable successful biopharmaceutical formulations. This work investigates the role of different non-ionic surfactants on protein conformational stability, as assessed by HSDSC, and on protein size stability as assessed by Dynamic Light Scattering (DLS), HIAC and MFI. BSA and IgG2 were used as model proteins. Thermal unfolding experiments indicated a very weak surfactant-immunoglobulin IgG2 interaction, compared to much stronger interactions for the BSA surfactant systems. The DLS results showed that BSA and IgG2 with different surfactants and concentration produced different levels of particle size growth. The heat treatment and aging of samples in the presence of Tween 20, Tween 80, Brij 35 and Pluronic F-68 surfactants led to an increase in the populations of larger particles for BSA samples, whereas IgG2 systems did not notably aggregate under storage conditions MFI was shown to be more sensitive than HIAC technique for measuring sub-visible particles in protein surfactant systems. Heat treatment and storage stress showed a significant effect on BSA and IgG2 protein sub-visible particle size stability. This work has demonstrated that both proteins with different Tween 20, Tween 80, Brij 35 and Pluronic F-68 concentrations, have different level of conformational and size stability. Also aging samples and heating stress bears the potential to generate particles, but this depends on surfactant type. Poor predictive correlations between the analytical methods were determined.