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•We apply a consistent framework to model impacts of PM2.5 from eight major sources.•50% ambient PM2.5 was from wood heaters, on-road sources and power stations.•Wood heaters were the ...most important source, responsible for 1,400 YLL annually.•Introduction of a 1.5 g/kg standard for wood heaters could produce 90,000 life-years.
We describe an assessment of the impact on mortality of eight major sources of PM2.5 in the Greater Metropolitan Region of Sydney, Australia (GMR). We modeled exposure to PM2.5 for the year July 2010 to June 2011 and estimated the burden of current mortality attributable to these sources. We also estimated the number of life-years that would be produced if emissions from wood heaters and power stations, the two largest emissions sources, were reduced.
Wood heaters (assuming a real-world emissions factor of 11.4 g of PM2.5 per kg of wood burned) were the most important source of PM2.5 exposure, responsible for around 24.0% of the total anthropogenic PM2.5 concentration. On-road sources and power stations were also important, responsible for 16.9% and 10.5% of anthropogenic PM2.5 exposure respectively.
Around 1.2% of mortality (5,900 YLL) was attributable to long-term exposure to all anthropogenic PM2.5, including 0.3% (1,400 YLL) attributable to wood heater–related PM2.5, 0.2% (990 YLL) to on-road sources and 0.1% (620 YLL) to power stations.
Compared to ongoing emissions at 2010/11 levels, we estimated that a sustained reduction in emissions from wood heaters due to the introduction of an emissions standard of 1.5 g of PM2.5 per kilogram of wood burned (real world emissions factor of 3.9 g of PM2.5 per kg of wood burned) and the associated reduction in PM2.5 population exposure would produce 90,000 life-years among the cohort of people alive in 2010/11. Complete removal of sulphur oxide emissions from power stations would produce 14,000 life-years and complete removal of nitrogen oxide emissions would produce 38,000 life-years. A range of sensitivity analyses indicate the true impact of PM2.5 from these sources is likely to be at least as large as these estimates.
This assessment shows that eight sources are responsible for more than 60% of exposure to anthropogenic PM2.5 in the Sydney GMR. Although the burden of mortality attributable to each source is relatively small, interventions that achieve sustained reductions in emissions could provide substantial health benefits, which are likely to far outweigh the costs.
Vascularized free flaps are now the reference standard for the reconstruction of defects after cancer resection in oral and maxillofacial surgery and other specialties and have an interesting and ...surprisingly long history. We reviewed the history of free flap use in oral and maxillofacial surgery and show their place in the wider context of surgical progress. An overview is given of both soft tissue and bony reconstruction in the pre–free flap era and the development of vascular anastomosis and microsurgery—one of the main foundations of free flap surgery. The emergence of free flaps from 1959 through to the early 1970s is documented. The history of 19 of the more common free flaps used in oral and maxillofacial surgery is described, from the jejunal flap in 1959 through to the posterior tibial artery flap in 1985. For each, the origin and first reported use in the head and neck are discussed. Free flap surgery has continued to evolve, with developments in perforator and chimeric flaps, and new flaps continue to be described. An appreciation of the surgical history is important in understanding where we are today. Our review should give the practicing surgeon an idea of the origins of the currently used techniques.
Epidemiological studies show that long-term exposure to ambient air pollution reduces life expectancy. Most studies have been in environments with relatively high concentrations such as North ...America, Europe and Asia. Associations at the lower end of the concentration-response function are not well defined.
We assessed associations between all-cause mortality and exposure to annual average particulate matter <2.5 μm (PM2.5) and nitrogen dioxide (NO2) in Sydney, Australia, where concentrations are relatively low.
The ‘45 and Up Study’ comprises a prospective longitudinal cohort from the state of New South Wales, Australia with 266,969 participants linked to death registry data. We analyzed data for the participants who resided in Sydney at baseline questionnaire (n = 75,268). Exposures to long-term pollution were estimated using annual averages from a chemical transport model (PM2.5), and a satellite-based land-use regression model (NO2). Socio-demographic information was extracted from the baseline questionnaire. Cox proportional hazard models were applied to estimate associations, while adjusting for covariates.
In our cohort mean annual PM2.5 was 4.5 μg/m3 and mean NO2 was 17.8 μg/m3. The mortality rate was 4.4% over the 7 years of follow up. Models that adjusted for individual-level and area-level risk factors resulted in a detrimental non statistically significant hazard ratio (HR) of 1.05 (95% CI: 0.98–1.12) per 1 μg/m3 increase in PM2.5, and 1.03 (95% CI: 0.98–1.07) per 5 μg/m3 increase in NO2.
We found evidence that low-level air pollution exposure was associated with increased risk of mortality in this cohort of adults aged 45 years and over, even at the relatively low concentrations seen in Sydney. However, a clear determination of the association with mortality is difficult because the results were sensitive to some covariates. Our findings are supportive of emerging evidence that exposure to low levels of air pollution reduces life expectancy.
•We report new information on the effects of long-term exposure to low levels of ambient air pollution on mortality•PM2.5 and NO2 had detrimental but non statistically significant associations with all-cause mortality at low concentrations•Our results were larger than comparable studies in higher pollution environments but were variable under the model sensitivity test•Exposure measurement error and other statistical issues complicate studies of air pollution concentrations at this low end of the spectrum•It is unknown if there is any safe low threshold of air pollution for health, and this is important as many countries strive to continuously reduce air pollution emission levels to protect public health
This study investigates the mortality effect of primary and secondary PM2.5 related to ship exhaust in the Sydney greater metropolitan region of Australia. A detailed inventory of ship exhaust ...emissions was used to model a) the 2010/11 concentration of ship-related PM2.5 across the region, and b) the reduction in PM2.5 concentration that would occur if ships used distillate fuel with a 0.1% sulfur content at berth or within 300km of Sydney. The annual loss of life attributable to 2010/11 levels of ship-related PM2.5 and the improvement in survival associated with use of low-sulfur fuel were estimated from the modelled concentrations.
In 2010/11, approximately 1.9% of the region-wide annual average population weighted-mean concentration of all natural and human-made PM2.5 was attributable to ship exhaust, and up to 9.4% at suburbs close to ports. An estimated 220years of life were lost by people who died in 2010/11 as a result of ship exhaust-related exposure (95% CIβ: 140–290, where CIβ is the uncertainty in the concentration-response coefficient only). Use of 0.1% sulfur fuel at berth would reduce the population weighted-mean concentration of PM2.5 related to ship exhaust by 25% and result in a gain of 390life-years over a twenty year period (95% CIβ: 260–520). Use of 0.1% sulfur fuel within 300km of Sydney would reduce the concentration by 56% and result in a gain of 920life-years over twenty years (95% CIβ: 600–1200).
Ship exhaust is an important source of human exposure to PM2.5 in the Sydney greater metropolitan region. This assessment supports intervention to reduce ship emissions in the GMR. Local strategies to limit the sulfur content of fuel would reduce exposure and will become increasingly beneficial as the shipping industry expands. A requirement for use of 0.1% sulfur fuel by ships within 300km of Sydney would provide more than twice the mortality benefit of a requirement for ships to use 0.1% sulfur fuel at berth.
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•PM2.5 related to ship exhaust was modelled from a high-resolution inventory of ship emissions.•Current human exposure and associated mortality was estimated.•The mortality benefit of using low-sulfur fuel was also assessed.•Ships are an important single source of PM2.5 in the Sydney region and have a public health impact.•Local action to reduce fuel sulfur content reduces this effect.
Short- and long-term spatiotemporal variation in exposure to air pollution is associated with respiratory morbidity in areas with moderate-to-high level of air pollution, but very few studies have ...examined whether these associations also exist in areas with low level exposure.
We assessed the association between spatial variation in long-term exposure to PM2.5 and NO2 and hospitalisation for all respiratory diseases, asthma, chronic obstructive pulmonary disease (COPD), and pneumonia, in older adults residing in Sydney, Australia, a city with low-level concentrations.
We recorded data on hospitalisations for 100,084 participants, who were aged >45 years at entry in 2006–2009 until June 2014. Annual NO2 and PM2.5 concentrations were estimated for the participants' residential addresses and Cox proportional hazards regression was used to model the association between exposure to air pollutants and first episode of hospitalisation, controlling for personal and area level covariates. We further investigated the shape of the exposure-response association and potential effect modification by age, sex, education level, smoking status, and BMI.
NO2 and PM2.5 annual mean exposure estimates were 17.5 μg·m−3 and 4.5 μg·m−3 respectively. NO2 and PM2.5 was positively, although not significantly, associated with asthma. The adjusted hazard ratio for a 1 μg·m−3 increase in PM2.5 was 1.08, 95% confidence interval 0.89–1.30. The adjusted hazard ratio for a 5 μg·m−3 increase in NO2 was 1.03, 95% confidence interval 0.88–1.19. We found no positive statistically significant associations with hospitalisation for all respiratory diseases, and pneumonia while negative associations were observed with COPD.
We found weak positive associations of exposure to air pollution with hospitalisation for asthma while there was no evidence of an association for all respiratory diseases.
•NO2 and PM2.5 were weakly associated with hospitalisation for asthma•No associations were found with hospitalisation for all respiratory diseases, and pneumonia•Effects of air pollution on asthma may persist at low levels of air pollution•Negative associations were observed with hospitalisation for COPD
Smoke haze events have increasingly affected Australia’s environmental quality, having demonstrable effects on air quality, climate, and public health. This study employs a hybrid methodology, ...merging satellite-based aerosol optical depth (AOD) data with Chemical Transport Model (CTM) simulations to comprehensively characterize these events. The AOD data are sourced from the Japan Aerospace Exploration Agency (JAXA), Copernicus Atmosphere Monitoring Service (CAMS), and the Commonwealth Scientific and Industrial Research Organization (CSIRO), and they are statistically evaluated using mean, standard deviation, and root mean square error (RMSE) metrics. Our analysis indicates that the combined dataset provides a more robust representation of smoke haze events than individual datasets. Additionally, the study investigates aerosol distribution patterns and data correlation across the blended dataset and discusses possible improvements such as data imputation and aerosol plume scaling. The outcomes of this investigation contribute to enhancing our understanding of the impacts of smoke haze on various environmental factors and can assist in developing targeted mitigation and management strategies.
Biomass burning aerosols influence the radiative balance of the earth-atmosphere system. They also reduce visibility and impact human health. In addition, trace gases and aerosols emitted to the ...atmosphere during large biomass burning episodes may have a significant effect on atmospheric chemistry due to the presence of reactive species.
Six hundred and ninety wildfires burned more than one million hectares in Victoria, Australia between December 2006 and February 2007. Thick smoke haze was transported to Melbourne (population 3.9 million) on several occasions, causing PM10 (particulate mass less than 10 μm in diameter) concentrations to exceed 200 μg m−3. The presence of elevated total secondary organic aerosol (SOA) and speciated SOA compounds (including pinene and cineole oxidation products), O3, and the larger aerosol mode diameter during smoke impacted periods indicated the presence of photochemical oxidation within the plume. The presence of organosulfate compounds and nitro-oxy organosulfate compounds indicated oxidation may have occurred in the presence of acidic seed aerosol and that oxidation may also have occurred at night.
Older smoke plumes (aged 30 h) displayed higher concentrations of a number of gaseous and aerosol species relative to the younger smoke plumes (aged 3 h). SOA compounds made up a greater fraction of speciated organic mass in the old plume than in the young plume where speciated biomass burning compounds dominated. Cineole oxidation products made up a greater fraction of the speciated SOA compounds in the old plume while pinene oxidation products made up a greater fraction of the total SOA speciated mass in the samples from the young plume. This may be a result of the slower reaction rate of cineole with OH. Organosulfate compounds and nitro-oxy organosulfate compounds made up greater fractions of the speciated SOA mass in the old plume consistent with the production of nitro-oxy organosulfate compounds under night time conditions in the presence of acidic seed.
These results suggest that enhanced photochemical activity occurs in smoke plumes and can significantly change the composition and microphysical properties of aerosol, potentially leading to changes in the optical and thus radiative properties of the aerosol.
•Plumes that impacted Aspendale resulted in elevated concentrations of particles and gases.•Old plumes showed evidence of more photochemistry than young plumes.•Speciated SOA compounds made up a greater fraction of speciated organic mass old plumes.•Speciated biomass burning compounds dominated the speciated organic mass in the young plumes.•Smoke plumes resulted in elevated concentrations of particles and gases.
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