Online Measurements during Simulated Atmospheric Aging Track the Strongly Increasing Oxidative Potential of Complex Combustion Aerosols Relative to Their Primary Emissions.

Oxidative potential (OP) is increasingly recognized as a more health-relevant metric than particulate matter (PM) mass concentration because of its response to varying chemical compositions. Given the limited research on the OP of complex combustion aerosols, the effects of aging processes on their OP remain underexplored. We used online instruments to track the evolution of OP [via dithiothreitol (DTT) assays] during the aging of wood burning and coal combustion emissions by hydroxyl-radical-driven photooxidation and dark ozonolysis.

Sensitivity Constraints of Extractive Electrospray for a Model System and Secondary Organic Aerosol.

The quantification of an aerosol chemical composition is complicated by the uncertainty in the sensitivity of each species detected. Soft-ionization response factors can vary widely from molecule to molecule. Here, we have employed a method to separate molecules by their volatility through systematic evaporation with a thermal denuder (TD).

Singlet Oxygen Seasonality in Aqueous PM is Driven by Biomass Burning and Anthropogenic Secondary Organic Aerosol.

The first excited state of molecular oxygen is singlet-state oxygen (O), formed by indirect photochemistry of chromophoric organic matter. To determine whether O can be a competitive atmospheric oxidant, we must first quantify its production in organic aerosols (OA). Here, we report the spatiotemporal distribution of O over a 1-year dataset of PM extracts at two locations in Switzerland, representing a rural and suburban site.