Emissions from wildland fires strongly influence tropospheric chemistry and climate. Fires emit high levels of trace gases, including semi-volatile and volatile organic compounds (S/VOCs); and primary (directly emitted) particulate matter (PM). During plume evolution, S/VOCs react to form ozone (O3) and secondary PM, thereby degrading air quality downwind. The amount of pollutants formed depends on fuel and fire characteristics, and plume dynamics and chemistry. In the western US and Canada, fire activity has been increasing over the last twenty years, attributed to changes in climate and fire management practices. Fire activity in the region is projected to worsen in future years, undoubtedly with severe impacts on air quality and climate. Unfortunately, model predictions of O3 and PM are characterized by significant uncertainties; limiting the utility of models to stakeholders tasked with minimizing potential impacts of fires on downwind communities. While there are a number of factors that lead to poor model predictions, research in our group has focused on three particular limitations: 1) incomplete identification and quantification of gaseous compounds emitted from fires that may serve as pollutant precursors; 2) incomplete understanding of the transformations of the precursors that lead to pollutant formation in smoke plumes; and 3) over-simplified representation of emissions and processes in current smoke and air quality models. In this talk, I will present an overview of our efforts in these areas, using advanced analytical techniques to characterize the S/VOCs in smoke as a function of fuel species and component, and chemically detailed box models to develop air quality model parameterizations.