Carbonyl compounds in the atmosphere at two different urban sites(Jianda and Chuangyeyuan)of Jinan were synchronously collected using 2,4-dinitrophenylhydrazine sampling tubes during a typical summer ozone pollution period(from June 14 to 22,2022)and quantified using high-performance liquid chromatography.The photochemical reactions of major carbonyls were simulated with the Observation-based model(OBM)to identify the secondary formation pathways and critical precursors of these carbonyl compounds.The total concentration of carbonyl compounds was(19.78±9.83)×10 9 of which formaldehyde,acetaldehyde,and acetone accounted for 36.75％,21.39％and 14.64％,respectively.The formaldehyde concentration showed"double peak"characteristics at noon and night in Jianda and had a peak change in morning and evening in Chuangyeyuan,exhibiting relatively higher concentrations at night and minimal concentrations around noontime.The concentration ratios of formaldehyde to acetaldehyde(C1/C2)of the two urban sites were 1.97 and 1.47,respectively.The concentration ratios of acetaldehyde to propionaldehyde(C2/C3)of the two sites were 9.27 and 8.76,respectively.The maximum formation rate was simulated to be 6.17×10-9h-1 for formaldehyde,1.67×10-9h-1 for acetaldehyde,and 0.66×10-9h 1 for acetone;and the alkoxy radical(RO)+O2 reaction was the main secondary formation pathway.We also observed that alkene had an important effect on the secondary formation of formaldehyde and acetaldehyde in the atmosphere;and ethylene,isoprene,and propylene were important precursors of formaldehyde,while propylene and 2-butylene served as precursors of acetaldehyde.Obviously,effectively controlling artificial alkene emissions from industries will help mitigate the secondary formation of major carbonyl compounds in the atmosphere.
维普
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