Chemical Characterization of Atmospheric Bioaerosols

Bioaerosols, or aerosol particles of biological origin, have been found to represent a significant mass fraction of atmospheric particulate matter (PM) and organic carbon (OC). These particles are larger in size (up to 100 µm) than most anthropogenic aerosols but are lighter and thus can be transported over long distances, affecting atmospheric processes and cloud physics (i.e., act as cloud condensation nuclei). Moreover, climate change is expected to increase pollen number concentrations (~21%) as well as pollen season length (+21 days) across North America. So far, only a few studies have been conducted on the chemical composition of bioaerosols and their behavior under atmospheric conditions. The goal of this research was to characterize the chemical composition of bioaerosols using multiple analytical techniques, such as Proton Nuclear Magnetic Resonance Spectroscopy (1H-NMR), Gas Chromatography-Mass Spectrometry (GC-MS), and Ultra-High Performance Liquid Chromatography-Mass Spectrometry (UPLC-MS), thereby advancing atmospheric aerosol chemistry. Various common bioaerosols, including pollen, algae, fungi, and bacteria, are analyzed, and characterized under controlled laboratory conditions. All samples are analyzed for their chemical composition: saccharides with GC-MS, amino acids and fatty acids with UPLC-MS, and functional groups with 1H-NMR spectroscopy. The present research is one of the first studies of detailed chemical characterization of bioaerosols with the 1H-NMR technique, where the 1H-NMR results are also compared with GC- and UPLC-MS quantitative analyses of individual bioaerosol species.