1 research outputs found
First Quantification of Imidazoles in Ambient Aerosol Particles: Potential Photosensitizers, Brown Carbon Constituents, and Hazardous Components
Imidazoles
are widely discussed in recent literature. They have been studied
as a secondary product of the reaction of dicarbonyls with nitrogen
containing compounds in a number of laboratory studies, potentially
acting as photosensitizers triggering secondary organic aerosol growth
and are forming constituents of light absorbing brown carbon. Despite
the knowledge from laboratory studies, no quantitative information
about imidazoles in ambient aerosol particles is available. Within
the present study, five imidazoles (1-butylimidazole, 1-ethylimidazole,
2-ethylimidazole, imidazol-2-carboxaldehyde, and 4(5)-methylimidazole)
were successfully identified and quantified for the first time in
ambient aerosol samples from different environments in Europe and
China. Their concentrations range between 0.2 and 14 ng/m<sup>3</sup>. 4(5)-Methylimidazole was found to be the most abundant imidazole.
The occurrence of imidazoles seems to be favored at sites with strong
biomass burning influence or connected to more polluted air masses.
No connection was found between aerosol particle pH and imidazole
concentration. Our work corroborates the laboratory studies by showing
that imidazoles are present in ambient aerosol samples in measurable
amounts. Moreover, it further motivates to explore the potential photosensitizing
properties of small alkyl-substituted imidazoles