Strategies to reduce wildfire smoke in frequently impacted communities in south-western Oregon

Background: Efforts to mitigate the adverse effects of wildfire smoke have focused on modifying human behaviour to minimise individual exposure, largely accomplished by providing smoke forecasts, monitoring, and consistent public messaging. Aims: To identify a strategy to reduce the amount of wildfire smoke in frequently impacted communities. Methods: We identify frequent air pathways that transport smoke into five communities in south-western Oregon. We present a case study comparing the potential change in the 24-h average PM2.5 concentration between fuels burned during a wildfire which are and are not treated prior to the incident. Key results: The concentration of PM2.5 would have decreased by 41% if fuel treatments occurred just prior to the wildfire. Of six vegetative strata, canopy, wood, and ground fuels contributed 88% of the total PM2.5 emissions, with shrub, herb, and lichen/litter/moss strata comprising the remaining 12%. Conclusions: Fuel treatments can substantially reduce smoke emission from subsequent wildfires and if located in consideration of meteorological patterns, these fuel treatments can reduce ambient concentrations of PM2.5. Implications: Fire and land managers can use the frequent air pathways and focus fuel treatments on the fuel beds and vegetative strata with the greatest potential to emit smoke during wildfires, to reduce the duration and concentration of wildfire smoke in frequently impacted communities.