Global population exposure to landscape fire air pollution from 2000 to 2019.

Wildfires are thought to be increasing in severity and frequency as a result of climate change1-5. Air pollution from landscape fires can negatively affect human health4-6, but human exposure to landscape fire-sourced (LFS) air pollution has not been well characterized at the global scale7-23. Here, we estimate global daily LFS outdoor fine particulate matter (PM2.5) and surface ozone concentrations at 0.25° × 0.25° resolution during the period 2000-2019 with the help of machine learning and chemical transport models. We found that overall population-weighted average LFS PM2.5 and ozone concentrations were 2.5 µg m-3 (6.1% of all-source PM2.5) and 3.2 µg m-3 (3.6% of all-source ozone), respectively, in 2010-2019, with a slight increase for PM2.5, but not for ozone, compared with 2000-2009. Central Africa, Southeast Asia, South America and Siberia experienced the highest LFS PM2.5 and ozone concentrations. The concentrations of LFS PM2.5 and ozone were about four times higher in low-income countries than in high-income countries. During the period 2010-2019, 2.18 billion people were exposed to at least 1 day of substantial LFS air pollution per year, with each person in the world having, on average, 9.9 days of exposure per year. These two metrics increased by 6.8% and 2.1%, respectively, compared with 2000-2009. Overall, we find that the global population is increasingly exposed to LFS air pollution, with socioeconomic disparities.

Climate Change, Landscape Fires, and Human Health: A Global Perspective.

Landscape fires are an integral component of the Earth system and a feature of prehistoric, subsistence, and industrial economies. Specific spatiotemporal patterns of landscape fire occur in different locations around the world, shaped by the interactions between environmental and human drivers of fire activity. Seven distinct types of landscape fire emerge from these interactions: remote area fires, wildfire disasters, savanna fires, Indigenous burning, prescribed burning, agricultural burning, and deforestation fires. All can have substantial impacts on human health and well-being directly and indirectly through (a) exposure to heat flux (e.g., injuries and destructive impacts), (b) emissions (e.g., smoke-related health impacts), and (c) altered ecosystem functioning (e.g., biodiversity, amenity, water quality, and climate impacts). Minimizing the adverse effects of landscape fires on population health requires understanding how human and environmental influences on fire impacts can be modified through interventions targeted at individual, community, and regional levels.

Wood heater smoke and mortality in the Australian Capital Territory: a rapid health impact assessment.

OBJECTIVES: To estimate the number of deaths and the cost of deaths attributable to wood heater smoke in the Australian Capital Territory. STUDY DESIGN: Rapid health impact assessment, based on fine particulate matter (PM2.5 ) data from three outdoor air pollution monitors and published exposure-response functions for natural cause mortality attributed to PM2.5 exposure. SETTING: Australian Capital Territory (population, 2021: 454 000), 2016-2018, 2021, and 2022 (2019 and 2020 excluded because of the impact of extreme bushfires on air quality). MAIN OUTCOME MEASURES: Proportion of PM2.5 exposure attributable to wood heaters; numbers of deaths and associated cost of deaths (based on the value of statistical life: $5.3 million) attributable to wood heater smoke. RESULTS: Wood heater emissions contributed an estimated 1.16-1.73 µg/m3 to the annual mean PM2.5 concentration during the three colder years (2017, 2018, 2021), or 17-25% of annual mean exposure, and 0.72 µg/m3 (15%) or 0.89 µg/m3 (13%) during the two milder years (2016, 2022). Using the most conservative exposure-response function, the estimated annual number of deaths attributable to wood heater smoke was 17-26 during the colder three years and 11-15 deaths during the milder two years. Using the least conservative exposure-response function, an estimated 43-63 deaths per year (colder years) and 26-36 deaths per year (milder years) were attributable to wood heater smoke. The estimated annual equivalent cost of deaths was $57-136 million (most conservative exposure-response function) and $140-333 million (least conservative exposure-response function). CONCLUSIONS: The estimated annual number of deaths in the ACT attributable to wood heater PM2.5 pollution is similar to that attributed to the extreme smoke of the 2019-20 Black Summer bushfires. The number of wood heaters should be reduced by banning new installations and phasing out existing units in urban and suburban areas.

Decrypting seasonal patterns of key pollen taxa in cool temperate Australia: A multi-barcode metabarcoding analysis.

Pollen allergies pose a considerable global public health concern. Allergy risk can vary significantly within plant families, yet some key pollen allergens can only be identified to family level by current optical methods. Pollen information with greater taxonomic resolution is therefore required to best support allergy prevention and self-management. We used environmental DNA (eDNA) metabarcoding to deepen taxonomic insights into the seasonal composition of airborne pollen in cool temperate Australia, a region with high rates of allergic respiratory disease. In Hobart, Tasmania, we collected routine weekly air samples from December 2018 until October 2020 and sequenced the internal transcribed spacer 2 (ITS2) and chloroplastic tRNA-Leucine tRNA-Phenylalanine intergenic spacer (trnL-trnF) regions in order to address the following questions: a) What is the genus-level diversity of known and potential aeroallergens in Hobart, in particular, in the families Poaceae, Cupressaceae and Myrtaceae? b) How do the atmospheric concentrations of these taxa change over time, and c) Does trnL-trnF enhance resolution of biodiversity when used in addition to ITS2? Our results suggest that individuals in the region are exposed to temperate grasses including Poa and Bromus in the peak grass pollen season, however low levels of exposure to the subtropical grass Cynodon may occur in autumn and winter. Within Cupressaceae, both metabarcodes showed that exposure is predominantly to pollen from the introduced genera Cupressus and Juniperus. Only ITS2 detected the native genus, Callitris. Both metabarcodes detected Eucalyptus as the major Myrtaceae genus, with trnL-trnF exhibiting primer bias for this family. These findings help refine our understanding of allergy triggers in Tasmania and highlight the utility of multiple metabarcodes in aerobiome studies.

Lung function changes in children exposed to mine fire smoke in infancy.

BACKGROUND AND OBJECTIVE: Chronic, low-intensity air pollution exposure has been consistently associated with reduced lung function throughout childhood. However, there is limited research regarding the implications of acute, high-intensity air pollution exposure. We aimed to determine whether there were any associations between early life exposure to such an episode and lung growth trajectories. METHODS: We conducted a prospective cohort study of children who lived in the vicinity of the Hazelwood coalmine fire. Lung function was measured using respiratory oscillometry. Z-scores were calculated for resistance (R5 ) and reactance at 5 Hz (X5 ) and area under the reactance curve (AX). Two sets of analyses were conducted: (i) linear regression to assess the cross-sectional relationship between post-natal exposure to mine fire-related particulate matter with an aerodynamic diameter of less than 2.5 micrometres (PM2.5 ) and lung function at the 7-year follow-up and (ii) linear mixed-effects models to determine whether there was any association between exposure and changes in lung function between the 3- and 7-year follow-ups. RESULTS: There were no associations between mine fire-related PM2.5 and any of the lung function measures, 7-years later. There were moderate improvements in X5 (ß: -0.37 [-0.64, -0.10] p = 0.009) and AX (ß: -0.40 [-0.72, -0.08] p = 0.014), between the 3- and 7-year follow-ups that were associated with mean PM2.5 , in the unadjusted and covariance-adjusted models. Similar trends were observed with maximum PM2.5 . CONCLUSION: There was a moderate improvement in lung stiffness of children exposed to PM2.5 from a local coalmine fire in infancy, consistent with an early deficit in lung function at 3-years after the fire that had resolved by 7-years.

Long-term exposure to low concentrations of air pollution and decline in lung function in people with idiopathic pulmonary fibrosis: Evidence from Australia.

BACKGROUND AND OBJECTIVE: Little is known about the association between ambient air pollution and idiopathic pulmonary fibrosis (IPF) in areas with lower levels of exposure. We aimed to investigate the impact of air pollution on lung function and rapid progression of IPF in Australia. METHODS: Participants were recruited from the Australian IPF Registry (n = 570). The impact of air pollution on changes in lung function was assessed using linear mixed models and Cox regression was used to investigate the association with rapid progression. RESULTS: Median (25th-75th percentiles) annual fine particulate matter (<2.5 µm, PM2.5 ) and nitrogen dioxide (NO2 ) were 6.8 (5.7, 7.9) µg/m3 and 6.7 (4.9, 8.2) ppb, respectively. Compared to living more than 100 m from a major road, living within 100 m was associated with a 1.3% predicted/year (95% confidence interval [CI] -2.4 to -0.3) faster annual decline in diffusing capacity of the lungs for carbon monoxide (DLco). Each interquartile range (IQR) of 2.2 µg/m3 increase in PM2.5 was associated with a 0.9% predicted/year (95% CI -1.6 to -0.3) faster annual decline in DLco, while there was no association observed with NO2 . There was also no association between air pollution and rapid progression of IPF. CONCLUSION: Living near a major road and increased PM2.5 were both associated with an increased rate of annual decline in DLco. This study adds to the evidence supporting the negative effects of air pollution on lung function decline in people with IPF living at low-level concentrations of exposure.

Asthma and landscape fire smoke: A Thoracic Society of Australia and New Zealand position statement.

Landscape fires are increasing in frequency and severity globally. In Australia, extreme bushfires cause a large and increasing health and socioeconomic burden for communities and governments. People with asthma are particularly vulnerable to the effects of landscape fire smoke (LFS) exposure. Here, we present a position statement from the Thoracic Society of Australia and New Zealand. Within this statement we provide a review of the impact of LFS on adults and children with asthma, highlighting the greater impact of LFS on vulnerable groups, particularly older people, pregnant women and Aboriginal and Torres Strait Islander peoples. We also highlight the development of asthma on the background of risk factors (smoking, occupation and atopy). Within this document we present advice for asthma management, smoke mitigation strategies and access to air quality information, that should be implemented during periods of LFS. We promote clinician awareness, and the implementation of public health messaging and preparation, especially for people with asthma.

No association between in utero exposure to emissions from a coalmine fire and post-natal lung function.

BACKGROUND AND OBJECTIVE: Studies linking early life exposure to air pollution and subsequent impaired lung health have focused on chronic, low-level exposures in urban settings. We aimed to determine whether in utero exposure to an acute, high-intensity air pollution episode impaired lung function 7-years later. METHOD: We conducted a prospective cohort study of children who lived in the vicinity of a coalmine fire. Respiratory function was measured using the forced oscillation technique (FOT). Z-scores for resistance at 5 Hz (R5), reactance at 5 Hz (X5) and area under the reactance curve (AX) were calculated. Two sets of analyses were conducted to address two separate questions: (1) whether mine fire exposure (a binary indicator; conceived after the mine fire vs in utero exposed) was associated with the respiratory Z-scores; (2) whether there was any dose-response relationship between fire-related PM2.5 exposure and respiratory outcomes among those exposed. RESULTS: Acceptable lung function measurements were obtained from 79 children; 25 unexposed and 54 exposed in utero. Median (interquartile range) for daily average and peak PM2.5 for the exposed children were 4.2 (2.6 - 14.2) and 88 (52-225) µg/m3 respectively. There were no detectable differences in Z-scores between unexposed and exposed children. There were no associations between respiratory Z-scores and in utero exposure to PM2.5 (daily average or peak). CONCLUSION: There was no detectable effect of in utero exposure to PM2.5 from a local coalmine fire on post-natal lung function 7-years later. However, statistical power was limited.

Exposure to air pollution concentrations of various intensities in early life and allergic sensitisation later in childhood.

BACKGROUND: Evidence on the relationship between air pollution and allergic sensitisation in childhood is inconsistent, and this relationship has not been investigated in the context of smoke events that are predicted to increase with climate change. Thus, we aimed to evaluate associations between exposure in two early life periods to severe levels of particulate matter with an aerodynamic diameter < 2.5 µm (PM2.5) from a mine fire, background PM2.5, and allergic sensitisation later in childhood. METHODS: We measured specific immunoglobulin E (IgE) levels for seven common aeroallergens as well as total IgE levels in a cohort of children who had been exposed to the Hazelwood coal mine fire, either in utero or during their first two years of life, in a regional area of Australia where ambient levels of PM2.5 are generally low. We estimated personal exposure to fire-specific emissions of PM2.5 based on a high-resolution meteorological and pollutant dispersion model and detailed reported movements of pregnant mothers and young children during the fire. We also estimated the usual background exposure to PM2.5 at the residential address at birth using a national satellite-based land-use regression model. Associations between both sources of PM2.5 and sensitisation to dust, cat, fungi, and grass seven years after the fire were estimated with logistic regression, while associations with total IgE levels were estimated with linear regression. RESULTS: No association was found between the levels of exposure at either developmental stage to fire-related PM2.5 and allergic sensitisation seven years after the event. However, levels of background exposure were positively associated with sensitisation to dust (OR = 1.90, 95%CI = 1.12,3.21 per 1 µg/m3). CONCLUSIONS: Chronic but low exposure to PM2.5 in early life could be more strongly associated with allergic sensitisation in childhood than time-limited high exposure levels, such as the ones experienced during landscape fires.

Thunderstorm asthma in seasonal allergic rhinitis: The TAISAR study.

BACKGROUND: Asthma epidemics associated with thunderstorms have had catastrophic effects on individuals and emergency services. Seasonal allergic rhinitis (SAR) is present in the vast majority of people who develop thunderstorm asthma (TA), but there is little evidence regarding risk factors for TA among the SAR population. OBJECTIVE: We sought to identify risk factors for a history of TA and hospital presentation in a cohort of individuals with SAR. METHODS: This multicenter study recruited adults from Melbourne, Australia, with a past diagnosis of TA and/or self-reported SAR. Clinical information, spirometry results, white blood cell count, ryegrass pollen-specific (RGP-sp) IgE concentration, and fractional exhaled nitric oxide were measured to identify risk factors for a history of TA in individuals with SAR. RESULTS: From a total of 228 individuals with SAR, 35% (80 of 228) reported SAR only (the I-SAR group), 37% (84 of 228) reported TA symptoms but had not attended hospital for treatment (the O-TA group), and 28% (64 of 228) had presented to the hospital for TA (the H-TA group). All patients in the H-TA group reported a previous asthma diagnosis. Logistic regression analysis of factors associated with O-TA and H-TA indicated that lower FEV1 value and an Asthma Control Questionnaire score higher than 1.5 were associated with H-TA. Higher blood RGP-sp IgE concentration, eosinophil counts, and fractional exhaled nitric oxide level were significantly associated with both O-TA and H-TA. Receiver operating curve analysis showed an RGP-sp IgE concentration higher than 10.1 kU/L and a prebronchodilator FEV1 value of 90% or lower to be biomarkers of increased H-TA risk. CONCLUSION: Clinical tests can identify risk of a history of TA in individuals with SAR and thereby inform patient-specific treatment recommendations.

Cardiac Autonomic Impacts of Bushfire Smoke-A Prospective Panel Study.

BACKGROUND: Air pollution is associated with cardiovascular disease and mortality. Most studies have focussed on urban or traffic-related pollution, and less is known about the impacts from bushfire smoke on cardiovascular autonomic function, although it is associated with increased sudden cardiac death and mortality. We sought to investigate its instantaneous and short-term impacts on heart rate variability (HRV). METHODS: Twenty-four (24)-hour Holter electrocardiography (ECG) was repeated twice (during bushfire [Phase 1] and then clean air [Phase 2]) in 32 participants from two Australian towns (Warburton and Traralgon, Victoria) surrounding planned burning areas. This was compared with 10 control participants in another town (Maffra, Victoria) with two clean air assessments during the same periods. The primary HRV parameters assessed were those assessing overall HRV (Standard Deviation of Normal-to-Normal intervals [SDNN]), long-term HRV (Standard Deviation of the Average of Normal Sinus-to-Normal Sinus intervals for each 5-minutes [SDANN]), low frequency [LF]) and short-term HRV (Root Mean Square of Successive Differences between N-N intervals [RMSSD], High Frequency [HF], LF:HF ratio). Average concentrations of particulate matter <2.5 µm in diameter (PM2.5) were measured at fixed site monitors in each location. RESULTS: Mean PM2.5 levels were significantly elevated during bushfire exposure in Warburton (96.5±57.7 µg/m3 vs 4.0±1.9 µg/m3, p<0.001) and Traralgon (12.6±4.9 µg/m3 vs 3.4±3.1 µg/m3, p<0.001), while it remained low in the control town, Maffra, in each phase (4.3±3.2 µg/m3 and 3.9±3.6 µg/m3, p=0.70). Although SDANN remained stable in controls, the exposed cohort showed significant worsening in SDANN during bushfire smoke exposure by 9.6±25.7ms (p=0.039). In univariable analysis, smoke exposure was significantly associated with higher ΔSDNN and ΔSDANN (p=0.03, p=0.01 exposed vs control). The association remained significant in ΔSDANN after adjusting for age, sex and cigarette smoking (p=0.02) and of borderline significance in ΔSDNN (p=0.06). CONCLUSIONS: Exposure to the bushfire smoke was independently associated with reduced overall and long-term HRV. Our findings suggest that imbalance in cardiac autonomic function is a key mechanism of adverse cardiovascular effects of bushfire smoke.

Short-Term Exposure to Sulfur Dioxide and Nitrogen Monoxide and Risk of Out-of-Hospital Cardiac Arrest.

BACKGROUND & AIMS: Over the past decades, particulate matter (PM), especially fine PM <2.5 µm in aerodynamic diameter (PM2.5) has been a major research focus. However, the air pollutant is a mixture of gases or vapour-phase compounds, such as carbon monoxide (C), nitrogen oxides (NOx), photochemical oxidants (Ox), and sulfur dioxide (SO2). Little is known about their cardiovascular effect, individually or in combination with PM. Thus, we aimed to determine the associations between the incidence of acute cardiac events and both gaseous and PM using a case-crossover design. METHODS: Cardiovascular cases were identified through the Gunma Prefectural Ambulance Activity Database in Japan in 2015 (1,512 out-of-hospital cardiac arrest [OHCA] and 1,002 heart failures from 53,006 ambulance cases). Air quality data from the nearest station was for day of the arrest (lag0) and 1-2 days before the arrest (lag1, lag2) and the moving average across days 0-1 (lag0-1). Conditional logistic regression was used for unadjusted and adjusted analysis for temperature and humidity. RESULTS: Independent associations of OHCA were daily concentrations of SO2 at lag1 (OR 1.173, 95%CI 1.004, 1.370; p=0.044) and lag0-1 (OR 1.203, 95%CI 1.015, 1.425; p=0.033); and daily NO concentrations at lag2 (OR 1.039, 95%CI 1.007, 1.072; p=0.016). The incidence of heart failure was significantly associated with daily concentrations of Ox on the day of the event in univariable model but not after adjustment for temperature and humidity. No associations were found for other pollutants. CONCLUSIONS: Short-term exposure to SO2 and NO are associated with an increased risk of OHCA.

The 2022 report of the MJA-Lancet Countdown on health and climate change: Australia unprepared and paying the price.

The MJA-Lancet Countdown on health and climate change in Australia was established in 2017 and produced its first national assessment in 2018 and annual updates in 2019, 2020 and 2021. It examines five broad domains: climate change impacts, exposures and vulnerability; adaptation, planning and resilience for health; mitigation actions and health co-benefits; economics and finance; and public and political engagement. In this, the fifth year of the MJA-Lancet Countdown, we track progress on an extensive suite of indicators across these five domains, accessing and presenting the latest data and further refining and developing our analyses. Within just two years, Australia has experienced two unprecedented national catastrophes - the 2019-2020 summer heatwaves and bushfires and the 2021-2022 torrential rains and flooding. Such events are costing lives and displacing tens of thousands of people. Further, our analysis shows that there are clear signs that Australia's health emergency management capacity substantially decreased in 2021. We find some signs of progress with respect to health and climate change. The states continue to lead the way in health and climate change adaptation planning, with the Victorian plan being published in early 2022. At the national level, we note progress in health and climate change research funding by the National Health and Medical Research Council. We now also see an acceleration in the uptake of electric vehicles and continued uptake of and employment in renewable energy. However, we also find Australia's transition to renewables and zero carbon remains unacceptably slow, and the Australian Government's continuing failure to produce a national climate change and health adaptation plan places the health and lives of Australians at unnecessary risk today, which does not bode well for the future.

Outdoor particulate matter exposure and upper respiratory tract infections in children and adolescents: A systematic review and meta-analysis.

BACKGROUND: While the relationship between outdoor particulate matter (PM) and lower respiratory tract infections in children and adolescents is accepted, we know little about the impacts of outdoor PM on the risk of developing or aggravating upper respiratory tract infections (URTIs). METHODS: We aimed to review the literature examining the relationship between outdoor PM exposure and URTIs in children and adolescents. A systematic search of EMBASE, MEDLINE, PubMed, Scopus, CINAHL and Web of Science databases was undertaken on April 3, 2020 and October 27, 2021. Comparable short-term studies of time-series or case-crossover designs were pooled in meta-analyses using random-effects models, while the remainder of studies were combined in a narrative analysis. Quality, risk of bias and level of evidence for health effects were appraised using a combination of emerging frameworks in environmental health. RESULTS: Out of 1366 articles identified, 34 were included in the systematic review and 16 of these were included in meta-analyses. Both PM2.5 and PM10 levels were associated with hospital presentations for URTIs (PM2.5: RR = 1.010, 95%CI = 1.007-1.014; PM10: RR = 1.016, 95%CI = 1.011-1.021) in the meta-analyses. Narrative analysis found unequivocally that total suspended particulates were associated with URTIs, but mixed results were found for PM2.5 and PM10 in both younger and older children. CONCLUSION: This study found some evidence of associations between PM and URTIs in children and adolescents, the relationship strength increased with PM10. However, the number of studies was limited and heterogeneity was considerable, thus there is a need for further studies, especially studies assessing long-term exposure and comparing sources.

The effects on mortality and the associated financial costs of wood heater pollution in a regional Australian city.

OBJECTIVES: To estimate the annual burden of mortality and the associated health costs attributable to air pollution from wood heaters in Armidale. DESIGN: Health impact assessment (excess annual mortality and financial costs) based upon atmospheric PM2.5 measurements. SETTING: Armidale, a regional Australian city (population, 24 504) with high levels of air pollution in winter caused by domestic wood heaters, 1 May 2018 - 30 April 2019. MAIN OUTCOME MEASURES: Estimated population exposure to PM2.5 from wood heaters; estimated numbers of premature deaths and years of life lost. RESULTS: Fourteen premature deaths (95% CI, 12-17 deaths) per year, corresponding to 210 (95% CI, 172-249) years of life lost, are attributable to long term exposure to wood heater PM2.5 pollution in Armidale. The estimated financial cost is $32.8 million (95% CI, $27.0-38.5 million), or $10 930 (95% CI, $9004-12 822) per wood heater per year. CONCLUSIONS: The substantial mortality and financial cost attributable to wood heating in Armidale indicates that effective policies are needed to reduce wood heater pollution, including public education about the effects of wood smoke on health, subsidies that encourage residents to switch to less polluting home heating (perhaps as part of an economic recovery package), assistance for those affected by wood smoke from other people, and regulations that reduce wood heater use (eg, by not permitting new wood heaters and requiring existing units to be removed when houses are sold).

The 2021 report of the MJA-Lancet Countdown on health and climate change: Australia increasingly out on a limb.

The MJA-Lancet Countdown on health and climate change in Australia was established in 2017, and produced its first national assessment in 2018, its first annual update in 2019, and its second annual update in 2020. It examines indicators across five broad domains: climate change impacts, exposures and vulnerability; adaptation, planning and resilience for health; mitigation actions and health co-benefits; economics and finance; and public and political engagement. Our special report in 2020 focused on the unprecedented and catastrophic 2019-20 Australian bushfire season, highlighting indicators that explore the relationships between health, climate change and bushfires. For 2021, we return to reporting on the full suite of indicators across each of the five domains and have added some new indicators. We find that Australians are increasingly exposed to and vulnerable to excess heat and that this is already limiting our way of life, increasing the risk of heat stress during outdoor sports, and decreasing work productivity across a range of sectors. Other weather extremes are also on the rise, resulting in escalating social, economic and health impacts. Climate change disproportionately threatens Indigenous Australians' wellbeing in multiple and complex ways. In response to these threats, we find positive action at the individual, local, state and territory levels, with growing uptake of rooftop solar and electric vehicles, and the beginnings of appropriate adaptation planning. However, this is severely undermined by national policies and actions that are contrary and increasingly place Australia out on a limb. Australia has responded well to the COVID-19 public health crisis (while still emerging from the bushfire crisis that preceded it) and it now needs to respond to and prepare for the health crises resulting from climate change.

Ambulance dispatches and heatwaves in Tasmania, Australia: A case-crossover analysis.

BACKGROUND: Climate change is causing an increase in the frequency and severity of heatwave events, with a corresponding negative impact on human health. Health service utilisation during a heatwave is increased, with a greater risk of poor health outcomes identified for specific population groups. In this study, we examined the impact of heatwave events on ambulance dispatches in Tasmania, Australia from 2008 to 2019 to explore health service utilisation and identify the most vulnerable populations at a local level. METHODS: We used a time-stratified case-crossover analysis with conditional logistic regression to examine the association between ambulance dispatches and three levels of heatwave events (extreme, severe, and low-intensity). We examined the relationship for the whole study population, and by age, gender, socio-economic advantage and clinical diagnostic group. RESULTS: We found that ambulance dispatches increase by 34% (OR 1.34, 95% CI 1.18-1.52) during extreme heatwaves, by 10% (OR 1.10, 95% CI 1.05-1.15) during severe heatwaves and by 4% (OR 1.04, 95% CI 1.02-1.06) during low-intensity heatwaves. We found significant associations for the elderly (over 65), the young (5 and under) and for regions with the greatest socio-economic disadvantage. CONCLUSION: Heatwaves were associated with increased demands on ambulance services in Tasmania. In subgroups of people aged over 65 or under 5 years of age, and those from areas of higher disadvantage, we generally observed greater effect sizes than for the population as a whole.

Adverse effects of prenatal exposure to residential dust on post-natal brain development.

BACKGROUND: Previous studies have shown an association between prenatal exposure to particulate matter (PM) and adverse brain development. However, it is unclear whether gestational exposure to community-sampled residential PM has an impact on the developing brain. OBJECTIVES: We aimed to test whether in utero exposure to PM from residential roof spaces (ceiling voids) alters critical foetal neurodevelopmental processes. METHODS: Pregnant C57BL/6 mice were intranasally exposed to 100 µg of roof space particles (~5 mg kg-1) in 50 µl of saline, or saline alone under light methoxyflurane anaesthesia, throughout mid-to-late gestation. At 2 weeks post-natal age, pups were sacrificed and assessed for body and brain growth. The brain tissue was collected and examined for a range of neurodevelopmental markers for synaptogenesis, synaptic plasticity, gliogenic events and myelination by immunohistochemistry. RESULTS: Gestational exposure to roof space PM reduced post-natal body and brain weights. There was no significant effect of roof space PM exposure on synaptogenesis, synaptic plasticity or astrocyte density. However, PM exposure caused increased myelin load in the white matter and elevated microglial density which was dependent on the PM sample. These effects were found to be consistent between male and female mice. CONCLUSIONS: Our data suggest that exposure to residential roof space PM during pregnancy impairs somatic growth and causes neuropathological changes in the developing brain.

Characterising non-linear associations between airborne pollen counts and respiratory symptoms from the AirRater smartphone app in Tasmania, Australia: A case time series approach.

Pollen is a well-established trigger of asthma and allergic rhinitis, yet concentration-response relationships, lagged effects, and interactions with other environmental factors remain poorly understood. Smartphone technology offers an opportunity to address these challenges using large, multi-year datasets that capture individual symptoms and exposures in real time. We aimed to characterise associations between six pollen types and respiratory symptoms logged by users of the AirRater smartphone app in Tasmania, Australia. We analyzed 44,820 symptom reports logged by 2272 AirRater app users in Tasmania over four years (2015-2019). With these data we evaluated associations between daily respiratory symptoms and atmospheric pollen concentrations. We implemented Poisson regression models, using the case time series approach designed for app-sourced data. We assessed potentially non-linear and lagged associations with (a) total pollen and (b) six individual pollen taxa. We adjusted for seasonality and meteorology and tested for interactions with particulate air pollution (PM2.5). We found evidence of non-linear associations between total pollen and respiratory symptoms for up to three days following exposure. For total pollen, the same-day relative risk (RR) increased to 1.31 (95% CI: 1.26-1.37) at a concentration of 50 grains/m3 before plateauing. Associations with individual pollen taxa were also non-linear with some diversity in shapes. For all pollen taxa the same-day RR was highest. The interaction between total pollen and PM2.5 was positive, with risks associated with pollen significantly higher in the presence of high concentrations of PM2.5. Our results support a non-linear response between airborne pollen and respiratory symptoms. The association was strongest on the day of exposure and synergistic with particulate air pollution. The associations found with Dodonaea and Myrtaceae highlight the need to further investigate the role of Australian native pollen types in allergic respiratory disease.

Associations between respiratory and vascular function in early childhood.

BACKGROUND AND OBJECTIVE: The link between respiratory and vascular health is well documented in adult populations. Impaired lung function is consistently associated with thicker arteries and higher incidence of cardiovascular disease. However, there are limited data on this relationship in young children and the studies that exist have focussed on populations at high risk of cardiorespiratory morbidity. We determined if an association exists between respiratory and cardiovascular function in young children and, if so, whether it is confounded by known cardiorespiratory risk factors. METHODS: Respiratory and vascular data from a prospective cohort study established to evaluate the health implications 3 years after coal mine fire smoke exposure in children aged 3-5 years were used. Respiratory function was measured using the forced oscillation technique and included resistance at 5 Hz (R5 ), reactance at 5 Hz (X5 ) and area under the reactance curve (AX). Vascular health was measured by carotid intima-media thickness (ultrasound) and pulse wave velocity (arterial tonometry). Regression analyses were used to examine the relationship between the respiratory Z-scores and cardiovascular measures. Subsequent analyses were adjusted for potential confounding by maternal smoking during pregnancy, maternal education and exposure to fine particulate matter <2.5 µm in aerodynamic diameter (PM2.5 ). RESULTS: Peripheral lung function (X5 and AX), but not respiratory system resistance (R5 ), was associated with vascular function. Adjustment for maternal smoking, maternal education and early life exposure to PM2.5 had minimal effect on these associations. CONCLUSION: These observations suggest that peripheral lung stiffness is associated with vascular stiffness and that this relationship is established early in life.