FIREX Science Questions

The following list of specific science questions can be addressed using a combination of the large-scale aircraft campaign and the smaller-scale field and laboratory experiments.

  1. What are the emissions of gases and aerosols from North American fires?
    • How do emissions depend on meteorology, fuel, time of day or night, and fire conditions?
    • How do the relative and absolute amounts of smoldering and flaming impact smoke composition and injection altitude?
    • What is the amount, composition, and volatility of aerosol precursors including the previously unidentified fraction of the emissions including SVOCs, IVOCs, and BC, BrC and OC aerosols?
    • What are the emissions of greenhouse gases and air toxics?
    • How well do inventories represent BB emissions and their radiative properties, and what are the largest uncertainties affecting the inventories?
  2. What chemical transformations affect those emissions?
    • What are the formation mechanisms for secondary species (ozone and secondary aerosol) and what environmental or chemical conditions control their relative importance?
    • How do aerosol optical and CCN properties evolve in fire plumes due to secondary production, particle phase transitions, and brown carbon bleaching and production?
    • How large are the variations in fire emissions compared to the changes from chemical processing?
    • What fraction of the organic aerosol is primary versus secondary at various time scales?
    • How do nighttime chemical transformations involving NO3, N2O5 and O3 influence the composition and evolution and the production of secondary organic aerosol in smoke plumes?
    • What are the mechanisms that lead to PAN formation in fire plumes during daytime and nighttime?
    • What is the diurnal cycle of free radical and oxidant production in fire plumes, and how important are reactions with different oxidants at various times of day
    • How important is the formation of organic aerosol from aqueous-phase processes?
  3. What is the local air quality impact of North American fires?
    • How well do local models predict the BB impact on air toxics including gases and aerosols, and visibility?
    • How does local meteorology impact fire evolution?
    • How large are the small-scale temporal and spatial gradients in fire plumes?
    • How important is nighttime smoke for populated areas and what are the health impacts?
    • How large are the regional impacts of small prescribed fires?
    • How much do small prescribed fires lead to population exposure?
  4. What are the regional and long-term impacts of North American fires?
    • How strongly are the composition and distribution of pollutants over North America influenced by BB?
    • How far afield can BB emissions from prescribed fires impact air quality?
    • What are the likely future changes in BB impacts that could result from climate change and changes to fire management practices?
  5. What are the climate-relevant properties of BB aerosols?
    • What roles do brown carbon and black carbon, other light-absorbing species, and internal mixtures play in the climate-relevant properties of smoke?
    • What intensive properties of BB aerosols can remote (i.e. satellite and AERONET) observations determine globally?
    • How well do regional and global models predict the BB influence on climate?
    • How can FIREX-AQ measurements improve remote retrievals of smoke?
  6. How can satellite measurements help with science questions #1-5?
    • How can improved measurements of plume height, fire intensity, and fire radiative power be used to adjust satellite retrievals?
    • How can satellite data be complemented by information, such as modeling, fuel characterization, aircraft and ground observations, to fully exploit their potential for constraining the magnitude and impact of fires?
    • How useful is thermal imaging of fires and documentation of field size for small fires for validating satellite active-fire count and burned-area products as well as fire radiative power (FRP)?
    • What is the relationship between FRP and emissions based on in situ measurements and can remote sensing of fire intensity be more effectively used to estimate of fire emissions of trace gases and aerosols?
    • Can lidar observations of depolarization contribute to speciation of aerosol types and evaluation of the age of smoke?
    • How accurate are NO2, CH2O and other trace gas retrievals (e.g., CHOCHO) in fire plumes and can these gases be used to assess air quality impacts (e.g., O3 sensitivities) associated with fires.