Seasonal and diurnal characteristics of atmospheric carbonyls in Nanning, China

• Carbonyls were firstly investigated in Nanning, Guangxi Province.
• Formaldehyde, acetaldehyde and acetone were the most abundant carbonyls.
• Photochemistry, solvent and fossil fuels are important sources for carbonyls.
• O3 formation potentials in summer and spring were significantly higher by ~ 2 times than those in autumn and winter.

For the first time, atmospheric carbonyls were measured to identify seasonal and diurnal variations in Nanning from October 2011 to July 2012. Formaldehyde (6.79 ± 3.39 μg/m3), acetaldehyde (15.81 ± 10.48 μg/m3) and acetone (5.43 ± 6.91 μg/m3) were the three most abundant carbonyls, accounting for ~ 85% of the total carbonyls. The average total concentrations of carbonyls and three abundant carbonyls showed significant high levels in summer compared to those in winter. Diurnal variations suggested that photochemical conditions, combustion of charcoal and straw, and solvent usage are important for the distributions of atmospheric carbonyls. The highest average C1/C2 ratio was observed in summer (0.75) compared to those (0.31–0.70) in other seasons, implying the positive effect of photochemical activities on raising C1/C2 ratio, and the significant low C2/C3 ratio (12.01–18.23) in winter and autumn than those (95.83–24.49) in both spring and summer suggested the important anthropogenic emissions such as charcoal and biomass combustion. O3 formation potentials in summer and spring were significantly higher by ~ 2 times than those in autumn and winter. Formaldehyde and acetaldehyde are the top two carbonyls which contribute 82–97% to total O3 formation potentials.