| Field observations were conducted using self-established PFPH-GC/MS method to measure carbonyl-containing volatile organic compounds (CVOCs) in the atmosphere of Guangzhou, including their composition, concentration and spatio-temporal variation. And their photochemical reactivity was quantitatively evaluated by calculating the OH reactivity (LOH) and ozone formation potential (OFP) respectively. Besides, it was analyzed that the impacts of emission sources, meteorological condition and sea-land breeze on the reactivity. Main conclusions were gained as following:1. A PFPH-GC/MS method was built up for the CVOCs measurment, and 21 kinds of compounds were detected in the atmosphere of Guangzhou which contains some important secondary carbonyl compounds, such as methylacrolein, glyoxal and methylglyoxal. The lowest detectable limit ranged among 0.008 and 0.028μg·m-3.2. The spatial distribution of CVOCs'total concentration was expressed as urban>suburban>rural area. The average concentration in the daytime were 19.29±3.85μg·m-3,19.19±7.84μg·m-3,17.79±3.50μg·m-3 at urban,suburban and rural area of Guangzhou during the autumn observation, respectively. Formaldehyde, acetaldehyde and acetone were the major CVOCs pollutants in the atmosphere of autumn, and the sum average concentration of these three compounds accounter for 62.1％,51.4% and 55.2% of the total CVOCs concentration at urban,suburban and rural area of Guangzhou, respectively.3. The total concentration of CVOCs in summer was higher than that in autumn, and the diurnal variation of CVOCs'total concentration showed a distinct single peak distribution with the peak value appearing during 9:00-15:00 everyday. The diurnal variation of CVOCs' concentration in the atmosphere of suburban and rural area was more complex due to the influence of emission sources, atmospheric transport, photochemical reactions and so on.4. The quantitative results of CVOCs'reactivity evaluated by LOH and OFP method had a good consistency. The total reactivity of CVOCs was closely related with their concentration, and represented a similar spatio-temporal distribution with the total concentration of CVOCs. Formaldehyde and acetaldehyde were the key active components with higher reactivity; acetone and benzaldehyde was the lowest LOH specie and the lowest OFP specie, respectively; the impact of methylglyoxal on ozone formation cannot be neglected in spite of its less advantageous concentration.5. Pollution emissions was an major influencing factor of CVOCs' reactivity, reducing the pollution emissions will result in the decrease of primary and secondary CVOCs' concentration; the reactivity of CVOCs had a positive correlation with the light intensity, and a negative correlation with wind speed, rainfall and other meteorological factors; the pollutants of urban area was likely to be transported to the rural area by the land breeze; the retention time of airborne CVOCs in rural area has been prolonged as well as their photochemical activity during the process when the land breeze turned round to sea breeze where the calm wind frequency has been enhanced; the reactivity of CVOCs would be decreased in the process of sea breeze which can dilute the concentration of CVOCs.
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