(416a) Oxidative Potential and Cellular Oxidant Production from Biomass Burning Aerosol

Exposure to particulate matter (PM) is a leading global health risk and has been associated with increased cardiopulmonary morbidity and mortality. Toxicological studies suggest that PM-induced reactive oxygen and nitrogen species (ROS/RNS) production may be a possible mechanism by which PM exposure leads to adverse health endpoints. Recent studies on the relative toxicities of different aerosol subtypes reported high relative toxicity for biomass burning aerosol in terms of oxidative potential.

Here, we present chemical oxidative potential and cellular oxidant production measurements from biomass burning aerosol collected in the southwestern part of the Brazilian Amazon region, where biomass burning emissions have drastically changed the composition of PM and have been shown to negatively impact the surrounding population. Samples were collected during the dry and wet seasons (n = 41). Dithiothreitol (DTT) was used to assess the oxidative potential or concentration of redox-active species present in the sample. Murine alveolar macrophages were exposed to PM extracts for 24 hrs, after which ROS/RNS production was measured. For all PM samples, a significant positive correlation was observed between ROS/RNS and concentrations of monosaccharide anhydride, such as levoglucosan. Exposure to pure levoglucosan was found to be non-toxic. Despite a lack of causation, levoglucosan may serve as an indicator of biomass burning health effects. ROS/RNS estimations were also calculated based on polycyclic aromatic hydrocarbon (PAH) concentrations and their respective ROS/RNS activity. The discrepancy between these estimations and ROS/RNS measured for the water-soluble hydrophobic fraction of PM suggests that concentration addition may not be an applicable mixture model for PM health effects.