Heterogenous Chemistry and Atmospheric Reactions of Organic Aerosols

Zachary Bohrer,* Tadini Masaya and Fabien Goulay, C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, WV 26506

Field (Broad Category): Chemistry (Physical Sciences & Engineering) 

Student’s Major: Chemical Engineer 

Heterogenous chemistry is when two species in different phases react, in this case gaseous free radicals and droplets of organic molecules. The process of heterogenous chemistry can be observed to better understand how suspended nanoparticles, or aerosols, react in an atmospheric environment. Heterogenous chemistry plays an important role in the chemical evolution of the atmosphere, such as cloud formation, ozone depletion, and pollution effects. This study determines the effects of OH radical reactions on pure and mixed solutions of organic nanoparticles. Experimental data were gathered by using solutions of organic molecules, such as glucose, lactose, urea, or acetamide, and dispersing small droplets through an atmospheric flow tube. Even though these organic particles may not be commonly found in the upper atmosphere they act as surrogates to improve our understanding of atmospheric reactions. While in the flow tube the organic particles reacted with OH radicals and were then sent to a scanning mobility particle sizer (SMPS) for particle size analysis. The chemical composition of the reacted particle is then determined by a gas chromatographer (GC). The data collected leads to the assumption that the density of the droplets may be changing due to the decrease of volume. The dramatic difference in diameter change of organic particles contradicts previous data collected on the effects of OH radicals on a mixture of monosaccharides and disaccharides. This new information can be used to understand how OH radicals effect different organic aerosols in Earth’s upper atmosphere. 

Funding: West Virginia University Start-up Package 

Program/mechanism supporting research/creative efforts: WVU's Research Apprenticeship Program (RAP) & accompanying HONR 297-level course