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Spatial modelling of woodsmoke concentrations and health risk associated with residential wood burning.Lightowlers, Christy 08 December 2008 (has links)
Within the context of global climate change and soaring energy prices, people are
searching for inexpensive and renewable sources of energy; therefore, burning wood for
home heating is increasing. Woodsmoke contains substances known to harm human
health and is a major contributor to air pollution in many parts of the world; yet there is
limited research into the health effects of woodsmoke and existing research suffers from
methodological constraints. As a result, there is interest in producing robust woodsmoke
exposure estimates for health research and air quality management purposes. Studying
health and the environment is inherently spatial; however, research related to air pollution
and health tends to be aspatial. As investigators begin to understand the influence of
spatial processes on research findings, the importance of adopting a spatial approach to
modelling exposure and health risk is becoming apparent. This thesis describes a spatially
explicit model for predicting fine particulate matter (PM2.5) attributable to woodsmoke
from residential heating in Victoria, British Columbia, Canada. Spatially resolved
measurements of PM2.5 were collected for 32 evenings during the winter heating seasons
of 2004/05, 2005/06, 2006/07 using a nephelometer installed in a passenger vehicle.
Positional data were collected concurrently using a Global Positioning System (GPS).
Levoglucosan, a chemical unique to woodsmoke, was measured to confirm the presence
of woodsmoke in the measured PM2.5. The spatial scale for the analysis of woodsmoke
data was determined using semivariograms to identify the maximum distance of spatial
dependence in the data which typically occurred near 2700m. Different spatial
approaches for modelling woodsmoke concentrations were evaluated both qualitatively in
terms of transferability, meeting statistical assumptions, and potential for exposure
misclassification; and quantitatively to assess the association between the model’s
predicted PM2.5 concentrations and observed PM2.5. The baseline model characterized
exposure based on the PM2.5 value from the closest fixed monitor (R=0.51, α=0.05). The
Krigged model produced a seasonal average surface based on nephelometer
measurements and showed the weakest performance (R=0.25, α=0.05). The regression
models predicted concentrations of woodsmoke based on predictor variables available
from census data, typically used in health research, and spatial property assessment data
(SPAD), an underused data source at a finer spatial resolution. Different approaches to
regression modelling were investigated. A regression model already developed for
Victoria performed the best quantitatively (R=0.84, α=0.05); however, qualitative
considerations precluded it from being selected as an appropriate model. A quantitatively
(R=0.62, α=0.05) and qualitatively robust regression model was developed using SPAD
(M6). SPAD improved the spatial resolution and model performance over census data.
Removing spatial and temporal autocorrelation in the data prior to modelling produced
the most robust model as opposed to modelling spatial effects post regression. A
Bayesian approach to M6 was applied; however, model performance remained
unchanged (R=0.62, α=0.05). The spatial distribution of susceptibility to health problems
associated with woodsmoke was derived from census data relating to population, age and
income. Intersecting the exposure model with population susceptibility in a Geographic
Information System (GIS) identified areas at high risk for health effects attributable to
woodsmoke.
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Acute cardiovascular effects of biofuel exhaust exposureUnosson, Jon January 2014 (has links)
Background Anthropogenic air pollution is a global health problem estimated to contribute to millions of premature deaths. Exposure to biomass smoke is common due to varying sources, such as wildfires, indoor cooking over open fires, and residential heating from wood stoves. In urban environments transportation and industry rely heavily on the combustion of fossil fuels yet environmental policies increasingly support a shift to renewable fuels such as biodiesel. It has not been investigated how either wood smoke or biodiesel exhaust affect human health in general or the cardiovascular system in particular. We hypothesized that wood smoke exposure would induce acute cardiovascular impairment via similar underlying mechanisms as have been established for petrodiesel exhaust exposure. We also hypothesized that replacing petrodiesel with biodiesel, as a blend or pure biodiesel, would generate an exhaust profile with a less harmful effect on the cardiovascular system than petrodiesel exhaust. Methods In four separate studies healthy non-smoking subjects were exposed to different air pollutants in controlled exposure chambers followed by clinical investigations of the cardiovascular system. All studies were performed as randomized controlled trials in a crossover fashion with each individual acting as her own control. In study I healthy volunteers were exposed to wood smoke at a target concentration of particulate matter (PM) 300 µg/m3 for three hours followed by measures of blood pressure, heart rate variability and central arterial stiffness. In study II subjects were exposed to wood smoke at a target concentration of PM 1000 µg/m3 for one hour followed by measures of thrombus formation using the Badimon technique and vasomotor function using forearm venous occlusion plethysmography. In study III subjects were exposed to petrodiesel exhaust and a 30% rapeseed methyl ester (RME30) biodiesel blend for one hour at a target concentration of PM 300 µg/m3. Following exposure, thrombus formation and vasomotor function were assessed as in study II. In study IV subjects were exposed to petrodiesel exhaust at a target concentration of PM 300 μg/m3for one hour and pure rapeseed methyl ester (RME100) exhaust generated at identical running conditions of the engine. Following exposure, thrombus formation and vasomotor function were assessed as in study II and III. Results In study I fourteen subjects (8 males) were exposed to wood smoke at P M 294±36 μg/m3. Compared to filtered air exposure, measures of central arterial stiffness were increased and heart rate variability was decreased following wood smoke exposure. No effect was seen on blood pressure. In study II sixteen males were exposed to wood smoke at PM 899±100 μg/m3. We found no evidence of increased thrombus formation or impaired vasomotor function following wood smoke exposure. In study III sixteen subjects (14 males) were exposed to petrodiesel exhaust (PM 314±27 µg/m3) and RME30 exhaust (PM 309±30 µg/m3). Thrombus formation and vasomotor function were equal following either exposure. In study IV nineteen males were exposed to petrodiesel exhaust (PM 310±34 µg/m3, 1.7±0.3 x105 particles/cm3) and RME100 exhaust (PM 165±16 µg/m3, 2.2±0.1 x105 particles/cm3). As in study III, thrombus formation and vasomotor function were identical following both exposures. Conclusions We have for the first time demonstrated that wood smoke exposure can increase central arterial stiffness and decrease heart rate variability in healthy subjects. We did not, however find evidence of increased thrombus formation and impaired vasomotor function following wood smoke exposure at a higher concentration for a shorter time period. We have, for the first time, demonstrated that exhaust from RME biodiesel induced acute adverse cardiovascular effects of increased thrombus formation and impaired vasomotor function in man. These effects are on par with those seen following exposure to petrodiesel exhaust, despite marked physicochemical differences of the exhaust characteristics.
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Impact of Biogas Digesters on Health and Quality of Life Measures of Kenyan FarmwomenDohoo, Carolyn 05 August 2011 (has links)
Women living in rural Kenya rely on wood for cooking and are exposed to elevated amounts of wood smoke. The objective of this thesis was to assess the health and quality of life benefits of installing biogas digesters on rural Kenyan dairy farms. Thirty-one farms with biogas digesters and 31 farms without digesters (referent group) were assessed for wood utilization practices, basic respiratory and self-reported health, and exposure to volatile organic compounds (VOCs). Women with biogas digesters spent less time and money acquiring wood, and less time exposed to wood smoke (p<0.01). Multivariable linear regression showed associations between daily wood consumption and having a biogas digester, family size, and number of cows. Individual VOCs were lower in cookhouses on biogas farms (p<0.001) and women with biogas digesters reported fewer respiratory symptoms. Biogas digesters are one technology that can reduce reliance on wood fuel and reduce exposures to harmful wood smoke.
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Effects of phosphate type, antimicrobials and processing methods on the quality, shelf-life and sensory characteristics of enhanced catfish filletsKin, Sovann 30 April 2011 (has links)
Catfish fillets that were enhanced with salt and various phosphate treatments through vacuum tumbling or multi-needle injection were evaluated for yield, protein exudate (only tumbling), surface color, pH, cooking loss, tenderness, purge loss and shelf-life. An agglomerated sodium phosphate blend (AGSP) was the optimum treatment for both vacuum tumbling and multi-needle injection and was further utilized in conjunction with potassium lactate (PL) and/or potassium acetate (PA) through vacuum tumbling to determine their effect on the quality, shelf-life and sensory characteristics of enhanced catfish fillets. In addition, the combination of AGSP and PA+PL that maximized shelf-life was further utilized in conjunction with liquid or wood smoking to evaluate the quality and inhibition of L. monocytogenes growth in ready-to-eat (RTE) smoked catfish fillets. All phosphate treatments increased (P<0.05) tenderness, but AGSP that contained mono-, tri-, and polyphosphates increased (P<0.05) pH and yield and decreased (P<0.05) yellowness in both tumbling and injection systems when compared to the control treatment. In addition, AGSP decreased (P<0.05) protein exudate when fillets were tumbled and increased (P<0.05) solution pick-up when injected. Psychrotrophic plate counts (PPC) for all phosphate treatments were similar to the control at each storage time and reached 7 log CFU/g by day 7 of storage; however, when AGSP was used in conjunction with PA+PL, PPC and sensory spoilage scores of raw catfish fillets were lower (P<0.05) than the control at each storage time. Marinating with a combination of 0.25% PA and 0.58% PL increased shelf-life (P<0.05) to between 10 and 14 days when compared to the control which had a shelf-life between 7 and 10 days. In addition, consumers preferred (P<0.05) fried catfish fillets that were treated with AGSP with and without PA+PL when compared to non-marinated controls with respect to appearance, flavor and overall acceptability. In conclusion, AGSP optimized yield and improved the quality of refrigerated catfish fillets, and extended shelf-life three days over other treatments when combined with PA+PL. This combined treatment also enhanced sensory properties of fried catfish fillets and had a synergistic effect with wood smoke constituents that inhibited the growth of L. monocytogenes on RTE smoked catfish fillets.
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TARGETED AND NON-TARGETED METABOLITE ANALYSIS FOR DISEASE RISK ASSESSMENT: MEASURING BIOMARKERS OF SMOKE EXPOSURE AND HABITUAL DIETWellington, Nadine L January 2019 (has links)
Exposomics applies metabolomics methods and technologies to the comprehensive
analysis of all low molecular weight molecules (< 1.5 kDa) in complex biological
samples to characterize the interaction between cellular metabolism and exogenous
lifestyle exposures that determine health and quality of life. To fully access the
diverse classes of biological molecules related to an individual’s metabolic profile,
metabolomics frequently requires the use of complementary analytical platforms,
and employs targeted and untargeted molecular profiling strategies to identify
biomarkers that are clinically relevant to an individual’s health status. Chapter 2
describes a quinoline-based boronic acid biosensor for N-acetylneuraminic acid that
undergoes a striking binding enhancement under strongly acidic conditions. For the
first time, this work allows for direct analysis of acidic sugars with high selectivity
when using UV absorbance or fluorescence detection based on formation of a
highly stable boronate ester complex with metabolites containing an α-hydroxycarboxylate moiety. Chapter 3 describes a targeted analysis of 24 different
organic contaminants using GC-MS that can serve as biomarkers of recent smoke
exposure following search-and-rescue training exercises by firefighters located at
three different sites across the province of Ontario. Importantly, skin and possible
respiratory uptake of various polycyclic aromatic hydrocarbons, methoxyphenols,
and resin acids was confirmed by peak excretion of several wood smoke biomarkers
in urine within 6 h following acute exposure. Chapter 4 applied a cross-platform
metabolomics strategy based on CE-MS and GC-MS in order to identify and
validate dietary biomarkers in matching plasma and urine samples collected from
healthy participants in the pilot Diet and Gene Interaction Study (DIGEST). For the
first time, we demonstrate that a panel of metabolites can serve as reliable
biomarkers following contrasting Prudent and Western diets over 2 weeks of food
provisions, which correlated well with self-reported diet records. This work paves the way for the development of objective biomarkers for accurate assessment of
wood smoke exposures, as well as complex dietary patterns as required for new
advances in occupational health and nutritional epidemiology. / Dissertation / Doctor of Philosophy (PhD) / Exposomics is an emerging multidisciplinary science aimed at deciphering the
complex interactions that impact human health and gene expression, such as
lifestyle choices (i.e., habitual diet) and lifelong environmental exposures. There is
growing interest in identifying biomarkers that can be readily measured for chronic
disease prevention given an alarming global prevalence of obesity and
cardiometabolic disorders, including heart disease, type 2 diabetes and cancer. The
research in this thesis focuses on developing new analytical methods for identifying
and quantifying metabolites that may allow for better assessments of human health,
and has contributed to the development of novel biosensors for the targeted analysis
of N-acetylneuraminic (sialic) acid and related acidic sugars, as well as high
resolution methods for broad spectrum analysis of biotransformed organic
contaminants from smoke exposure by GC-MS, and plasma and urinary metabolites
that differentiate contrasting Prudent and Western diets and correlate well with self-reported
diet records.
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