Speciation and Aqueous Dissolution of Macronutrients in Fire Ash: Variation across Ecosystems and the Effects on Nutrient Cycling.

This study investigated the speciation and aqueous dissolution of macronutrients in fire ash from diverse ecosystems and speciation of ash and smoke from laboratory burning, exploring the variations and their causes. The speciation of phosphorus (P), calcium (Ca), and potassium (K) in fire ash from five globally distributed ecosystems was characterized by using X-ray absorption spectroscopy and sequential fractionation. Aqueous dissolution of the macronutrients was measured by batch experiments at acidic and alkaline pHs.

Aqueous Photolysis of Water-Soluble Brown Carbon from Simulated Prescribed and Wildfire Biomass Burning.

This work, as part of the Georgia Wildland fire Simulation Experiment (G-WISE) campaign, explores the aqueous photolysis of water-soluble brown carbon (W-BrC) in biomass burning aerosols from the combustion of fuel beds collected from three distinct ecoregions in Georgia: Piedmont, Coastal Plain, and Blue Ridge. Burns were conducted under conditions representative of wildfires, which are common unplanned occurrences in Southeastern forests (low fuel moisture content), and prescribed fires, which are commonly used in forest management (higher fuel moisture content). Upon exposure to radiation from UV lamps equivalent to approximately 5 h in the atmosphere, the absorption spectra of all six samples exhibited up to 40% photobleaching in the UV range (280-400 nm) and as much as 30% photo-enhancement in the visible range (400-500 nm).

Optical Properties of Biomass Burning Aerosols from Simulated Wildfires and Prescribed Fires with Representative Fuel Beds from the Southeast United States.

We report measurements of the absorption Ångström exponent (AAE) and single scattering albedo (SSA) of biomass burning aerosol from the combustion of fuel beds representing three eco-regions of the Southeast U.S. (Piedmont, Coastal Plain, and Blue Ridge Mountains) with moisture content representative of wildfires and prescribed fires.

Brown Carbon Emissions from Biomass Burning under Simulated Wildfire and Prescribed-Fire Conditions.

We investigated the light-absorption properties of brown carbon (BrC) as part of the Georgia Wildland-Fire Simulation Experiment. We constructed fuel beds representative of three ecoregions in the Southeastern U.S.

Alkylperoxy radicals are responsible for the formation of oxygenated primary organic aerosol.

Organic aerosol (OA) is an air pollutant ubiquitous in urban atmospheres. Urban OA is usually apportioned into primary OA (POA), mostly emitted by mobile sources, and secondary OA (SOA), which forms in the atmosphere due to oxidation of gas-phase precursors from anthropogenic and biogenic sources. By performing coordinated measurements in the particle phase and the gas phase, we show that the alkylperoxy radical chemistry that is responsible for low-temperature ignition also leads to the formation of oxygenated POA (OxyPOA).