Assessing the health benefits and economic costs of interventions to reduce exposure to air pollution from biomass combustion in Australia.

Fine particulate matter (PM2.5) pollution related to biomass combustion is an established driver of poor health outcomes. While interventions such as face masks and portable air cleaners (PACs) reduce exposure, the health benefits and cost effectiveness of these interventions are not well understood. In this study, we modelled the benefits and costs of face masks and PACs across eight capital cities in Australia. We used historic daily PM2.5 concentrations coupled with fire activity and temperature data to create a statistically representative year of data. We used established concentration-response functions for long-term exposure to PM2.5 to estimate reductions in mortality risk and monetised them using the value of a statistical life. We calculated intervention costs by considering investment and operating expenses. We calculated the PM2.5 reduction potential and the benefit-cost ratio (BCR) as measures to compare interventions, using Monte Carlo simulation to account for uncertainty. All interventions were found to have a BCR above 1. Despite being the least effective intervention for reducing personal PM2.5 exposure, surgical masks, used for 3.6 h during smoky days, had the greatest BCR compared to P2/N95 masks, home-made PACs and branded PACs (BCR > 18.8 surgical masks; BCR > 3.7 P2/N95 masks; BCR > 1.8 home-made PACs; BCR > 1.4 branded PACs). This was due to the very low unit cost of surgical masks. Overall, the health benefits of using face masks and/or PACs outweighed the economic costs.