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Background: In 2014, the Hazelwood coalmine fire shrouded the regional Australian town of Morwell in smoke and ash for 6 weeks. One of the fire's by-products, PM 2.5 , is associated with an increased risk of COVID-19 and severe disease. However, it is unclear whether the effect persisted for years after exposure. In this study, we surveyed a cohort established prior to the pandemic to determine whether PM 2.5 from the coalmine fire increased long-term vulnerability to COVID-19 and severe disease., Methods: From August to December 2022, 612 members of the Hazelwood Health Study's adult cohort, established in 2016/17, participated in a follow-up survey that included standardized items to capture COVID-19 cases, as well as questions about hospitalization and vaccinations. Associations were evaluated in crude and adjusted logistic regression models., Results: A total of 268 (44%) participants self-reported or met symptom criteria for having had COVID-19 at least once. All models found a positive association, with odds of COVID-19 increasing by between 4% and 30% for a 10 μg/m 3 increase in coalmine fire-related PM 2.5 exposure. However, the association was significant in only 2 of the 18 models. There were insufficient hospitalizations to examine severity (n = 7; 1%)., Conclusion: The findings are inconclusive on the effect of coalmine fire-related PM 2.5 exposure on long-term vulnerability to COVID-19. Given the positive association that was robust to modelling variations as well as evidence for a causal mechanism, it would be prudent to treat PM 2.5 from fire events as a long-term risk factor until more evidence accumulates., (© 2023 The Authors. Respirology published by John Wiley & Sons Australia, Ltd on behalf of Asian Pacific Society of Respirology.)

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 (PM 2.5 ) from a mine fire, background PM 2.5 , 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 PM 2.5 are generally low. We estimated personal exposure to fire-specific emissions of PM 2.5 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 PM 2.5 at the residential address at birth using a national satellite-based land-use regression model. Associations between both sources of PM 2.5 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 PM 2.5 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/m 3 )., Conclusions: Chronic but low exposure to PM 2.5 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., (© 2023. The Author(s).)

Background: Episodic spikes in air pollution due to landscape fires are increasing, and their potential for longer term health impacts is uncertain., Objective: Our objective is to evaluate associations between exposure in utero and in infancy to severe pollution from a mine fire, background ambient air pollution, and subsequent hospital care., Methods: We linked health records of births, emergency department (ED) visits, and hospitalizations of children born in the Latrobe Valley, Australia, 2012-2015, which included a severe pollution episode from a mine fire (9 February 2014 to 25 March 2014). We assigned modeled exposure estimates for fire-related and ambient particulate matter with an aerodynamic diameter of 2.5 μ m ( PM 2.5 ) to residential address. We used logistic regression to estimate associations with hospital visits for any cause and groupings of infectious, allergic, and respiratory conditions. Outcomes were assessed for the first year of life in the in utero cohort and the year following the fire in the infant cohort. We estimated exposure-response for both fire-related and ambient PM 2.5 and also employed inverse probability weighting using the propensity score to compare exposed and not/minimally exposed children., Results: Prenatal exposure to fire-related PM 2.5 was associated with ED presentations for allergies/skin rash [odds ratio ( OR ) = 1.34 , 95% confidence interval (CI): 1.01, 1.76 per 240   μ g / m 3 increase]. Exposure in utero to ambient PM 2.5 was associated with overall presentations ( OR = 1.18 , 95% CI: 1.05, 1.33 per 1.4   μ g / m 3 ) and visits for infections (ED: OR = 1.13 , 95% CI: 0.98, 1.29; hospitalizations: OR = 1.23 , 95% CI: 1.00, 1.52). Exposure in infancy to fire-related PM 2.5 compared to no/minimal exposure, was associated with ED presentations for respiratory ( OR = 1.37 , 95% CI: 1.05, 1.80) and infectious conditions (any: OR = 1.21 , 95% CI: 0.98, 1.49; respiratory-related: OR = 1.39 , 95% CI: 1.05, 1.83). Early life exposure to ambient PM 2.5 was associated with overall ED visits ( OR = 1.17 , 95% CI: 1.05, 1.30 per 1.4   μ g / m 3 increase)., Discussion: Higher episodic and lower ambient concentrations of PM 2.5 in early life were associated with visits for allergic, respiratory, and infectious conditions. Our findings also indicated differences in associations at the two developmental stages. https://doi.org/10.1289/EHP12238.

Background: Due to climate change, landscape fires account for an increasing proportion of air pollution emissions, and their impacts on primary and pharmaceutical care are little understood., Objectives: To evaluate associations between exposure in two early life periods to severe levels of PM 2.5 from a mine fire, background PM 2.5 , and primary and pharmaceutical care., Methods: We linked records of births, general practitioner (GP) presentations and prescription dispensing for children born in the Latrobe Valley, Australia, 2012-2014, where a severe mine fire occurred in February-March 2014 in an area with otherwise low levels of ambient PM 2.5 . We assigned modelled exposure estimates for fire-related (cumulative over the fire and peak 24-hour average) and annual ambient PM 2.5 to residential address. Associations with GP presentations and dispensing of prescribed medications in the first two years of life (exposure in utero) and in the two years post-fire (exposure in infancy) were estimated using two-pollutant quasi-Poisson regression models., Results: Exposure in utero to fire-related PM 2.5 was associated with an increase in systemic steroid dispensing (Cumulative: IRR = 1.11, 95%CI = 1.00-1.24 per 240 μg/m 3 ; Peak: IRR = 1.15, 95%CI = 1.00-1.32 per 45 μg/m 3 ), while exposure in infancy was associated with antibiotic dispensing (Cumulative: IRR = 1.05, 95%CI = 1.00-1.09; Peak: IRR = 1.06, 95%CI = 1.00-1.12). Exposure in infancy to ambient PM 2.5 , despite relatively low levels from a global perspective (Median = 6.1 μg/m 3 ), was associated with an increase in antibiotics (IRR = 1.10, 95%CI = 1.01-1.19 per 1.4 μg/m 3 ) and in GP presentations (IRR = 1.05, 95%CI = 1.00-1.11), independently from exposure to the fire. We also observed differences in associations between sexes with GP presentations (stronger in girls) and steroid skin cream dispensing (stronger in boys)., Discussion: Severe medium-term concentrations of PM 2.5 were linked with increased pharmaceutical treatment for infections, while chronic low levels were associated with increased prescriptions dispensed for infections and primary care usage. Our findings also indicated differences between sexes., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Fay Johnston reports financial support was provided by Victoria Department of Health and Human Services. Shyamali Dharmage reports a relationship with AstraZeneca plc that includes: funding grants. Shyamali Dharmage reports a relationship with GSK plc that includes: funding grants., (Copyright © 2023 The Author(s). Published by Elsevier B.V. All rights reserved.)

Background: In 2014, wildfires ignited a coal mine in Australia, burning for 6 weeks, releasing large amounts of fine particulate matter ≤2.5 μm in diameter (PM 2.5 ). We investigated the association between individual PM 2.5 exposure and emergency department presentations (EDPs) within 5 years post-fire., Methods: Survey and exposure data for 2725 residents from an exposed and unexposed town were linked with ED administrative data from 2009 to 2019. The association between individual PM 2.5 and EDPs was assessed using recurrent survival analysis., Results: A 10 μg/m 3 increase in PM 2.5 was associated with a 10% increase in respiratory EDPs (HR = 1.10; 95%CI:1.00-1.22) over 5 years post-fire. Increased risks of EDPs for ischaemic heart disease (HR = 1.39; 95%CI:1.12-1.73), atherothrombotic disease (HR = 1.27; 95%CI:1.08-1.50), and cardiovascular disease (HR = 1.10, 95%CI:0.99-1.22) were evident within 2.5 years., Conclusion: PM 2.5 exposure from a 6-week mine fire increased the 5-year risk of respiratory conditions. An increased risk of CVD within 2.5 years post-fire subsided after this time., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Michael Abramson reports a relationship with Pfizer that includes: funding grants. Michael Abramson reports a relationship with Boehringer-Ingelheim that includes: funding grants. Michael Abramson reports a relationship with Sanofi that includes: consulting or advisory and funding grants. Michael Abramson reports a relationship with GSK that includes: funding grants and speaking and lecture fees. Dion Stub reports a relationship with National Heart Foundation of Australia that includes: funding grants. Yuming Guo reports a relationship with Australian National Health and Medical Research Council that includes: funding grants., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Due to climate change, catastrophic events such as landscape fires are increasing in frequency and severity. However, relatively little is known about the longer-term mental health outcomes of such events. Follow-up was conducted of 709 adults exposed to smoke from the 2014 Hazelwood mine fire in Morwell, Victoria, Australia. Participants completed two surveys evaluating posttraumatic distress, measured using the Impact of Events Scale-Revised (IES-R), three and six years after the mine fire. Mixed-effects regression models were used to evaluate longitudinal changes in distress. IES-R total scores increased on average by 2.6 points (95%CI: 1.2 to 3.9 points) between the two survey rounds, with increases across all three posttraumatic distress symptom clusters, particularly intrusive symptoms. This increase in distress was evident across all levels of fine particulate matter (PM 2.5 ) exposure to the mine fire smoke. Age was an effect modifier between mine fire PM 2.5 exposure and posttraumatic distress, with younger adults impacted more by exposure to the mine fire. Greater exposure to PM 2.5 from the mine fire was still associated with increased psychological distress some six years later, with the overall level of distress increasing between the two survey rounds. The follow-up survey coincided with the Black Summer bushfire season in south-eastern Australia and exposure to this new smoke event may have triggered distress sensitivities stemming from exposure to the earlier mine fire. Public health responses to disaster events should take into consideration prior exposures and vulnerable groups, particularly younger adults., (Copyright © 2022 Elsevier GmbH. All rights reserved.)

Background: Little is known about the long-term health impacts of exposures to landscape fire smoke. We aimed to evaluate the association between exposure to coal mine fire-related particulate matter 2.5 μm or less in diameter (PM2.5) and hospitalisation in the 5 years following the 6-week Hazelwood coal mine fire in Australia in 2014., Methods: We surveyed 2725 residents (mean age: 58.3 years; 54.3% female) from an exposed and a comparison town. Individual PM2.5 exposures during the event were estimated using modelled PM2.5 concentrations related to the coal mine fire and self-reported location data. The individual exposure and survey data were linked with hospitalisation records between January 2009 and February 2019. Recurrent event survival analysis was used to evaluate relationships between PM2.5 exposure and hospitalisation following mine fire, adjusting for important covariates., Results: Each 10-µg/m3 increase in mine fire-related PM2.5 was associated with a 9% increased hazard [hazard ratio (HR) = 1.09; 95% confidence interval (CI): 1.01, 1.17] of respiratory hospitalisation over the next 5 years, with stronger associations observed for females (HR = 1.16; 95% CI: 1.06, 1.27) than males (HR = 0.99; 95% CI: 0.89, 1.11). In particular, increased hazards were observed for hospitalisations for asthma (HR = 1.43; 95% CI: 1.19, 1.73) and chronic obstructive pulmonary disease (HR = 1.14; 95% CI: 1.02, 1.28). No such association was found for hospitalisations for cardiovascular diseases, mental illness, injuries, type 2 diabetes, renal diseases or neoplasms., Conclusions: A 6-week exposure to coal mine fire-related PM2.5 was associated with increased hazard of respiratory hospitalisations over the following 5 years, particularly for females., (© The Author(s) 2021; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association.)

Background: Little is known about the long-term health effects of coalmine fire smoke exposure. The 2014 Hazelwood coalmine fire event in southeast Australia released smoke into surrounding areas for 6 weeks., Objectives: We aimed to investigate whether individual-level exposure to coalmine fire-related PM 2.5 was associated with a long-term increase in ambulance attendances following a coalmine fire event., Methods: A total of 2223 residents from the most exposed town of Morwell were assessed for ambulance attendances after the Hazelwood event from April 1, 2014 to December 31, 2017. PM 2.5 exposure was estimated for each individual using participant self-reported location diary data during the event and modelled PM 2.5 concentrations. Recurrent event survival analysis was used to evaluate the relationship between PM 2.5 exposure and ambulance attendances., Results: For each 10 μg/m 3 increase in mean coalmine fire-related PM 2.5 exposure, there was a 10% (adjusted hazard ratio [HR]:1.10, 95%CI:1.03-1.17) increase in the overall risk of ambulance attendances within 3.5 years after the coalmine fire. Exposure to PM 2.5 was also associated with increased risk of respiratory (HR: 1.21, 95%CI: 1.02-1.44) and cardiovascular (HR: 1.13, 95%CI: 1.01-1.28) related ambulance attendances., Conclusion: These results demonstrate that exposure to coalmine fire smoke during the Hazelwood event was associated with a long-term health risk post the fire event, specifically for respiratory and cardiovascular conditions. These findings are important for effective implementation of health care services following future extended coalmine fire PM 2.5 events., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Rationale: In 2014, the Hazelwood open-cut coal mine in southeastern Australia burned for 6 weeks, exposing nearby residents to high concentrations of fine particulate matter (PM 2.5 ). The long-term health consequences are unknown and are being evaluated as part of the Hazelwood Health Study. Objectives: To explore the association between PM 2.5 exposure and chronic obstructive pulmonary disease (COPD). Methods: A sample of 346 exposed and 173 unexposed adults participated in the longitudinal Respiratory Stream of the Hazelwood Health Study. Participants underwent spirometry and gas transfer measurements and answered validated respiratory questionnaires 3.5-4 years after the fire. Individual-level mine fire-related PM 2.5 exposure was modeled. Multivariate linear regression and logistic models were fitted to analyze associations between mean and peak PM 2.5 exposure and clinical outcomes, stratified by smoking status. Results: A 10 μg/m 3 increase in mean PM 2.5 exposure was associated with a 69% (95% confidence interval [CI], 11-158%) increase in odds of spirometry consistent with COPD among nonsmokers and increased odds of chest tightness (odds ratio [OR], 1.30; 95% CI, 1.03-1.64) and chronic cough (OR, 1.24; 95% CI, 1.02-1.51) in the previous 12 months in all participants. For current smokers, increments in mean PM 2.5 exposure were associated with higher odds of chronic cough in the preceding 12 months (OR, 2.13; 95% CI, 1.24-3.65). Conclusions: Almost 4 years after a 6-week period of coal fire PM 2.5 exposure, we identified a dose-response association between exposure and COPD in nonsmokers. With climate change a likely contributor to increased risk of landscape fires, the findings will inform policy decisions during future sustained smoke events.

Background and Objective: In 2014, a 6-week-long fire at the Hazelwood coal mine exposed residents in the adjacent town of Morwell to high concentrations of fine particulate matter with an aerodynamic diameter < 2.5 μm (PM 2.5 ). The long-term health consequences are being evaluated as part of the Hazelwood Health Study., Methods: Approximately 3.5-4 years after the mine fire, adults from Morwell (n = 346) and the comparison town Sale (n = 173) participated in the longitudinal Respiratory Stream of the Study. Individual PM 2.5 exposure was retrospectively modelled. Lung mechanics were assessed using the forced oscillation technique (FOT), utilizing pressure waves to measure respiratory system resistance (Rrs) and reactance (Xrs). Multivariate linear regression was used to evaluate associations between PM 2.5 and transformed Rrs at 5 Hz, area under the reactance curve (AX5) and Xrs at 5 Hz controlling for key confounders., Results: There were clear dose-response relationships between increasing mine fire PM 2.5 and worsening lung mechanics, including a reduction in post-bronchodilator (BD) Xrs5 and an increase in AX5. A 10 μg/m 3 increase in mine fire-related PM 2.5 was associated with a 0.015 (95% CI: 0.004, 0.027) reduction in exponential (Xrs5) post-BD, which was comparable to 4.7 years of ageing. Similarly, the effect of exposure was associated with a 0.072 (0.005, 0.138) increase in natural log (lnAX5) post-BD, equivalent to 3.9 years of ageing., Conclusion: This is the first study using FOT in adults evaluating long-term respiratory outcomes after medium-term ambient PM 2.5 exposure to coal mine fire smoke. These results should inform public health policies and planning for future events., (© 2021 Asian Pacific Society of Respirology.)

Background: For six weeks from February 9, 2014, smoke and ash from a fire in the Morwell open cut brown coal mine adjacent to the Hazelwood power station covered parts of the Latrobe Valley, in south eastern Australia., Aims: To evaluate the health impact of the mine fire, daily counts of ambulance attendances from July 2010 to March 2015 were analysed., Methods: Time series models were used to evaluate the relative risk of ambulance attendances during the mine fire, in comparison with the remainder of the analysis period, and to also assess the risk of ambulance attendances associated with lagged effects of exposure to mine fire-related PM 2.5 levels. The models controlled for factors likely to influence ambulance attendances including seasonality, long-term temporal trends, day of the week, daily maximum temperature and public holidays., Results: A 10 μg/m 3 increase in fire-related PM 2.5 was found to be associated with a 42% (95%CI: 14-76%) increase in ambulance attendances for respiratory conditions and a 7% (0-14%) increase in all ambulance attendances over a 20-day lag period. A smaller effect associated with exposure to fire-related PM 2.5 was identified when assuming shorter lag effects. Similar results were identified when assessing whether ambulance attendances increased during the 30-day mine fire period. There was a 15% (8-21%) increased risk of ambulance attendances for all conditions and a 47% (19-81%) increased risk for respiratory conditions during the mine fire period., Conclusions: Exposure to smoke and ash from a fire in an open cut brown coal mine was associated with increased ambulance attendances, particularly for respiratory conditions. These findings guide the development and implementation of effective and timely strategies and health service planning to respond and mitigate health risks that arise in affected communities during future major air pollution episodes., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Although the association between long-term exposure to PM 2.5 and mortality has been evaluated intensively, little is known about the socioeconomic disparity in the association., Methods: We collected data on annual all-cause mortality, PM 2.5 concentration, socioeconomic and demographic characteristics of 2640 counties from the two most recent Chinese censuses in 2000 and 2010. We applied the difference-in-differences (DID) method to estimate PM 2.5 -mortality association for counties at different quartiles of literacy rate, college rate, urbanization rate and GDP per capita, respectively., Results: Overall, every 10 µg/m 3 increase in annual average PM 2.5 was associated with 3.8% (95% confidence interval [CI]: 3.0-5.0) increase of all-cause mortality. The stratified analysis suggested higher health impact of exposure in counties with lower socioeconomic status. For counties of the lowest quartile (Q 1 ) of literacy rate, college rate, urbanization rate and GDP per capita, the effect estimates were 6.0% (95% CI: 4.2-7.7), 4.4% (95% CI: 2.8-6.0), 3.5% (95% CI: 2.0-5.1) and 4.9% (95% CI: 2.7-7.1), respectively. There was strong evidence for elevated risk in mortality associated with PM 2.5 of all socioeconomic factors in the lowest quartile (Q 1 ) compared with the highest quartile counties (Q 4 ) (p-value for difference < 0.05)., Conclusions: There was socioeconomic disparity in the PM 2.5 -mortality association in China. Dwellers living in less developed counties are more vulnerable to long-term exposure to ambient PM 2.5 than those living in developed counties., (Copyright © 2020 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

In February 2014, the coalmine adjacent to the Hazelwood Power Station in the Latrobe Valley of Victoria, Australia, caught fire, with residents from the nearby town of Morwell and the wider area exposed to smoke for six weeks. Although there was evidence linking the mine-fire event with psychological distress, no studies have evaluated the degree of distress in relation to the level of smoke exposure. We aimed to investigate the exposure-response relationship between particulate matter 2.5 μm or less in diameter (PM 2.5 ) released during the Hazelwood mine fire event and long-term symptoms of posttraumatic distress in the affected community, including the consideration of other key factors. A total of 3096 Morwell residents, and 960 residents from the largely unexposed comparison community of Sale, were assessed for symptoms of posttraumatic distress 2.5 years after the Hazelwood incident using the Impact of Events Scale-Revised (IES-R). Individual-level PM 2.5 exposure was estimated by mapping participants' self-reported location data on modelled PM 2.5 concentrations related to the mine fire. Multivariate linear regression was used to evaluate the exposure-response relationship. Both mean and peak exposure to mine fire-related PM 2.5 were found to be associated with participant IES-R scores with an interaction effect between age and mean PM 2.5 exposure also identified. Each 10 μg/m 3 increase in mean PM 2.5 exposure corresponded to a 0.98 increase in IES-R score (95% CI: 0.36 to 1.61), and each 100 μg/m 3 increase in peak PM 2.5 exposure corresponded to a 0.36 increase (95% CI: 0.06 to 0.67). An age-effect was observed, with the exposure-response association found to be stronger for younger adults. The results suggest that increased exposure to PM 2.5 emissions from the Hazelwood mine fire event was associated with higher levels of psychological distress associated with the mine fire and the most pronounced effect was on younger adults living in the affected community., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background: This study assessed the association between coal-mine-fire-related fine particulate matter (PM2.5) and medical-service utilization, following a 6-week coal-mine fire in Australia, in 2014. Areas in the immediate vicinity of the mine experienced hourly mine-fire-related PM2.5 concentrations of up to 3700 μg/m3., Methods: Data on medical-service utilization were collected from the Medicare Benefits Schedule-a national database of payment for medical services. PM2.5 concentrations were modelled using atmospheric chemical transport modelling. Quasi-Poisson interrupted distributed lag time-series analysis examined the association between daily mine-fire-related PM2.5 concentrations and medical-service utilization, including General Practitioner (GP) consultations and respiratory, cardiovascular and mental health services. Confounders included seasonality, long-term trend, day of the week, maximum daily temperature and public holidays. Gender and age stratification were conducted., Results: A 10-μg/m3 increase in PM2.5 was associated with an increased relative risk of service usage for all long and short GP consultations [11% (95% confidence interval: 7 to 15%)] and respiratory services [22% (4 to 43%)] in both men and women. Sex stratification found an increased relative risk in mental health consultations in men [32% (2 to 72%)] but not women. No associations were found for cardiovascular services in men or women., Conclusions: Coal-mine-fire-related PM2.5 exposure was associated with increased use of medical services for GP consultations and respiratory services in men and women and mental health consultations in men. These findings can inform the development of future public-health-policy responses in the event of major air-pollution episodes., (© The Author(s) 2019; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association.)

Juan Mundisugih,1,2 Caroline X Gao,1,3 Jillian F Ikin,1 Michael J Abramson,1 David Brown,1 Sinjini Biswas,1,2 Elizabeth M Dewar,2,4 Danny Liew,1 Dion Stub1,2,4 1School of Public Health and Preventive Medicine, Monash University, Melbourne, VIC, Australia; 2Department of Cardiology, Alfred Health, Melbourne, VIC, Australia; 3Centre for Youth Mental Health (Orygen), University of Melbourne, Melbourne, VIC, Australia; 4Baker Heart and Diabetes Institute, Melbourne, VIC, AustraliaCorrespondence: Jillian F Ikin, Tel +61 3 9903 0308, Email jill.blackman@monash.eduBackground and Aims: Mega-wild fires are exposing large communities to weeks or months of high concentration smoke-related fine particulate air pollution (PM). However, little research has examined the long-term vascular responses from exposure to PM of this concentration and duration. We investigated whether level of exposure to 6 weeks of PM from the 2014 Hazelwood coal mine fire was associated with abnormal vascular responses approximately four years later.Methods: A cross-sectional analysis was undertaken of 387 participants (225 exposed, 162 unexposed) aged 55– 89 years, 3.5– 4 years after the mine fire. The primary outcome was flow-mediated dilatation (FMD), with time to reach peak diameter as the secondary outcome. Other secondary markers included high-sensitivity C-reactive protein (hsCRP) and ischaemic Electrocardiogram (ECG) changes.Results: There was no evidence of a difference in FMD between participants with high, medium, low or no mine-fire related PM2.5 exposure (4.09% vs 4.06% vs 4.02% vs 3.98%, respectively, p=0.99). Likewise, there was no difference in hsCRP or ischaemic ECG changes. In contrast, there was evidence of a difference in time to peak diameter (p=0.002) with more unexposed participants reaching peak diameter within 30 seconds (36%) compared to those who had high, medium, or low exposure (23%, 22%, 13%, respectively). Multivariate ordinal logistic regression analysis suggested that township, Morwell (exposed) vs Sale (unexposed), but not level of PM2.5 exposure, was associated with delayed time to peak diameter (OR 2.71; 95% CI 1.56, 4.69). Smokers also had delayed time to peak diameter.Conclusion: There was no association between level of exposure to PM2.5 from the 6-week Hazelwood coal mine fire smoke event and reduced FMD, elevated hsCRP or ischaemic ECG four years later. Evidence of delayed time to peak diameter observed in adults from the exposed town, compared to an unexposed town, requires further investigation.Keywords: vascular responses, flow mediated dilatation, time to peak diameter, particulate matter, epidemiology, air pollution