Evaluating portable air cleaner effectiveness in residential settings to reduce exposures to biomass smoke resulting from prescribed burns

AIM: Prescribed burning is the most common method employed to reduce fuel loads in flammable landscapes. This practice is designed to reduce the hazard associated with uncontrolled bushfires. Prescribed burns are frequently conducted close to residential areas, and the associated smoke impacts can adversely affect community health. Particulate matter is the predominant pollutant within the smoke and is strongly and consistently linked with adverse health effects. Outdoor smoke readily infiltrates buildings and reduces the quality of indoor air. Portable air cleaners containing high-efficiency particulate air (HEPA) filters are a promising indoor air quality intervention for reducing outdoor smoke exposure.METHODS: We provided 10 homes from semirural regions of Victoria, Australia, with HEPA cleaners and conducted continuous monitoring of indoor and outdoor fine particulate matter (PM2.5) for 2-4 weeks during prescribed burning periods. We calculated the potential improvements to indoor air quality when operating a HEPA cleaner during a smoke episode. Ventilation measures were conducted to identify points of smoke ingress and housing characteristics that could lead to higher infiltration rates.RESULTS: Depending on the house, the use of HEPA cleaners resulted in a reduction in indoor PM2.5 concentrations of 30-74%.CONCLUSIONS: HEPA cleaners have the potential to substantially improve indoor air quality during episodic smoke episodes.</p

Fine particulate matter (PM < inf > 2.5 < /inf > ) exposure during a prolonged wildfire period and emergency department visits for asthma

Background and objective: The 2006–2007 wildfire period was one of the most extensive and long lasting fires in Australian history with high levels of fine particulate matter (PM2.5). Large populations were exposed to smoke for over 2 months. The study aimed to investigate the association between wildfire-related PM2.5 exposure and emergency department (ED) visits for asthma. Methods: A time-stratified case-crossover design was used to investigate associations between daily average PM2.5and ED attendances for asthma from December 2006 to January 2007. ED data were obtained from the Victorian Emergency Minimum Dataset. Smoke dispersion during the wildfire event was modelled using a validated chemical transport model. Exposure data (daily average PM2.5, temperature and relative humidity) were modelled for the study period. Various lag periods were investigated. Results: There were 2047 ED attendances for asthma during the study period. After adjusting for temperature and relative humidity, an interquartile range increase in PM2.5 levels of 8.6 μg/m3 was associated with an increase in ED attendances for asthma by 1.96% (95%CI: 0.02, 3.94) on the day of exposure. Lag periods up to 2 days prior did not show any association. A strong association was observed among women 20 years and older (5.08% 95%CI: 1.76, 8.51). Conclusions: Wildfire-related PM2.5 was associated with increased risk of ED attendance for asthma during the wildfire event. It is important to understand the role of wildfire PM2.5 as a trigger for asthma presentations

Developing a conceptual framework for environmental health tracking in Victoria, Australia

Victoria&#8217;s (Australia) Environment Protection Authority (EPA), the state&#8217;s environmental regulator, has recognized the need to develop an Environmental Health Tracking System (EHTS) to better understand environmental health relationships. To facilitate the process of developing an EHTS; a linkage-based conceptual framework was developed to link routinely collected environmental and health data to better understand environmental health relationships. This involved researching and drawing on knowledge from previous similar projects. While several conceptual frameworks have been used to organize data to support the development of an environmental health tracking system, Driving Force&#8722;Pressure&#8722;State&#8722;Exposure&#8722;Effect&#8722;Action (DPSEEA) was identified as the most broadly applied conceptual framework. Exposure and effects are two important components of DPSEEA, and currently, exposure data are not available for the EHTS. Therefore, DPSEEA was modified to the Driving Force&#8722;Pressure&#8722;Environmental Condition&#8722;Health Impact&#8722;Action (DPEHA) conceptual framework for the proposed Victorian EHTS as there is relevant data available for tracking. The potential application of DPEHA for environmental health tracking was demonstrated through case studies. DPEHA will be a useful tool to support the implementation of Victoria&#8217;s environmental health tracking system for providing timely and scientific evidence for EPA and other decision makers in developing and evaluating policies for protecting public health and the environment in Victoria

Health effects of smoke from planned burns: a study protocol

Abstract Background Large populations are exposed to smoke from bushfires and planned burns. Studies investigating the association between bushfire smoke and health have typically used hospital or ambulance data and been done retrospectively on large populations. The present study is designed to prospectively assess the association between individual level health outcomes and exposure to smoke from planned burns. Methods/design A prospective cohort study will be conducted during a planned burn season in three locations in Victoria (Australia) involving 50 adult participants who undergo three rounds of cardiorespiratory medical tests, including measurements for lung inflammation, endothelial function, heart rate variability and markers of inflammation. In addition daily symptoms and twice daily lung function are recorded. Outdoor particulate air pollution is continuously measured during the study period in these locations. The data will be analysed using mixed effect models adjusting for confounders. Discussion Planned burns depend on weather conditions and dryness of ‘fuels’ (i.e. forest). It is potentially possible that no favourable conditions occur during the study period. To reduce the risk of this occurring, three separate locations have been identified as having a high likelihood of planned burn smoke exposure during the study period, with the full study being rolled out in two of these three locations. A limitation of this study is exposure misclassification as outdoor measurements will be conducted as a measure for personal exposures. However this misclassification will be reduced as participants are only eligible if they live in close proximity to the monitors

Impact of fine particulate matter (PM < inf > 2.5 < /inf > ) exposure during wildfires on cardiovascular health outcomes

Background: Epidemiological studies investigating the role of fine particulate matter (PM2.5; aerodynamic diameter < 2.5 μm) in triggering acute coronary events, including out‐of‐hospital cardiac arrests and ischemic heart disease (IHD), during wildfires have been inconclusive. Methods and Results: We examined the associations of out‐of‐hospital cardiac arrests, IHD, acute myocardial infarction, and angina (hospital admissions and emergency department attendance) with PM2.5 concentrations during the 2006–2007 wildfires in Victoria, Australia, using a time‐stratified case‐crossover study design. Health data were obtained from comprehensive health‐based administrative registries for the study period (December 2006 to January 2007). Modeled and validated air exposure data from wildfire smoke emissions (daily average PM2.5, temperature, relative humidity) were also estimated for this period. There were 457 out‐of‐hospital cardiac arrests, 2106 emergency department visits, and 3274 hospital admissions for IHD. After adjusting for temperature and relative humidity, an increase in interquartile range of 9.04 μg/m3 in PM2.5 over 2 days moving average (lag 0‐1) was associated with a 6.98% (95% CI 1.03% to 13.29%) increase in risk of out‐of‐hospital cardiac arrests, with strong association shown by men (9.05%,95%CI 1.63% to 17.02%) and by older adults (aged ≥65 years) (7.25%, 95% CI 0.24% to 14.75%). Increase in risk was (2.07%, 95% CI 0.09% to 4.09%) for IHD‐related emergency department attendance and (1.86%, 95% CI: 0.35% to 3.4%) for IHD‐related hospital admissions at lag 2 days, with strong associations shown by women (3.21%, 95% CI 0.81% to 5.67%) and by older adults (2.41%, 95% CI 0.82% to 5.67%). Conclusion: PM2.5 exposure was associated with increased risk of out‐of‐hospital cardiac arrests and IHD during the 2006–2007 wildfires in Victoria. This evidence indicates that PM2.5 may act as a triggering factor for acute coronary events during wildfire episodes