Diurnal Variations in Partitioning of Atmospheric Glyoxal and Methylglyoxal between Gas and Particles at the Ground Level and in the Free Troposphere

Abstract

This work presents diurnal variations of gas- and particle-phase dicarbonyls (glyoxal (Gly) and methylglyoxal (Mgly)) in the atmosphere, which are important compounds that contribute to the formation and growth of atmospheric particulate matter. To obtain variations in partitioning, continuous collection of gaseous dicarbonyls was performed using a parallel plate wet denuder, and at the same time, the dicarbonyls in particle were collected using a spray-type particle collector downstream. Hourly samples were analyzed by high performance liquid chromatography–electrospray ionization–tandem mass spectrometry. This method is advantageous to monitor the gaseous and particulate carbonyls separately without loss during sampling. Sampling was performed in summer and winter in a midsize city (Kumamoto, Japan). The concentrations of the dicarbonyls increased in the summer daytime, which suggests that they are mostly formed by secondary production in the local atmosphere. The dicarbonyls and formaldehyde (HCHO) wer...