The atmospheric chemistry that affects organic aerosol (OA) composition is very complicated, as numerous factors including temperature, humidity, and reactive species can determine it. Additionally, there is a continuous influx of thousands of different volatile organic compounds (VOCs), which can be the source of SOA, into the atmosphere from diverse sources. Accordingly, controlled experiments are essential in order to improve our fundamental understanding of the fate of OA in the atmosphere and its potential impact on air quality and climate change. The KU AC2 Lab will leverage simulation tools such as smog chambers or flow reactors. When these tools are integrated with state-of-the-art instrumentations such as a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) or A Filter Inlet for Gases and AEROsol coupled with a high-resolution time-of-flight chemical ionization mass spectrometer (FIGAERO-HR-ToF-CIMS), we can identify the oxidation mechanism that forms OA and track the evolution of OA composition during atmospheric aging.

OA released into the atmosphere via various anthropogenic or biogenic activities can impact climate change. OA is recognized for its ability to scatter the sunlight, generally contributing to the reductions in global temperature. However, the brown carbon (BrC) component present in OA can have a contrasting effect by absorbing sunlight across the ultraviolet to visible wavelength that increases the temperature. Furthermore, climate change can affect the air quality by altering emission patterns of biogenic and anthropogenic VOCs as well as the atmospheric oxidation chemistry. Such interconnections between air quality and climate change are very complicated, and KU AC2 Lab will tackle this complexity through the integration of both laboratory and ambient field experiments. 

KU AC2 Lab leverages various tools to identify the sources of OA. This would be the first and priority step to control air quality successfully, as OA can come from multiple sources such as biomass burning, vehicles, cooking, and secondary oxidation of biogenic and anthropogenic VOCs. In the OA community, positive matrix factorization (PMF) analysis is frequently applied to the OA dataset measured using an HR-ToF-AMS or an aerosol chemical speciation monitor (ACSM) to untangle the complexity in source identification. In addition to the statistical analysis, carbon and nitrogen aerosol isotope analysis can provide a more direct indication when the ratios are compared with the source of OA. 

Exposure to aerosol size below 2.5 μm has been reported to be associated with detrimental health effects and substantial numbers of deaths. Such risks can be evaluated by determining oxidative stress that can potentially driven by aerosol composition. Recent studies showed that the oxidation level of OA can determine the reactive oxygen species (ROS) in the aerosol that can result in oxidative stress, which can induce PM toxicity. KU AC2 Lab will further explore the effect of atmospheric chemical composition on human/public health.