Atmospheric aerosols can cause adverse health effects in humans and can contribute to both global cooling and global warming. Aerosols that reflect sunlight are known to contribute to global cooling. Dark colored aerosols can absorb visible and UV light from the sun and radiate this energy as heat which contributes to global warming. The pH of our atmosphere is approx. 2-5 so compounds within aerosols exist in an acidic environment. Researchers commonly study aerosols at a neutral or slightly acidic pH. However, if pH is shown to affect the structures of these compounds and therefore affect how they react, it could have implications for future laboratory experiments. The light absorbance of methylglyoxal, glyoxal, and glycolaldehyde (known light absorbing compounds found in aerosols) were tested at varying pH levels. The absorbance of all three compounds were found to be affected by pH. To test other possible factors involved in absorbance, buffer composition as well as the concentrations of each compound were varied. 1H NMR and 13C NMR spectra was acquired for all three at varying pH levels to see how the structures were changing to account for the difference in absorbance. Structural differences were observed at varying pH levels. This suggests the structures were affected by pH and most likely the cause of the absorbance difference.

Effect of pH on the absorbance and structure of compounds within atmospheric aerosols

255th National Meeting (2018)

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