The Study On The Spatial-temporal Distribution Of Volatile Carbonyls In Atmosphere Of The Pearl River Delta

Carbonyls are some kinds of volatile organic pollutants and include aldehydes and ketonescompounds, can be easily measured both in indoor and outdoor air. They are formed byatmospheric photochemistry reaction, and could product OH radical, alkyl radical, ozone,carboxylic acid peroxyacetyl nitrates by atmospheric photochemistry reaction. Carbonyls havereceived more and more attention due to their adverse health effects and their important role inthe atmospheric chemistry.A method of measuring the volatile carbonyls in atmosphere by high performance liquidchromatography was established in this study. Firstly, a self-made packed absorbent column wasinvented to sample the volatile carbonyls, with the saturated solution of2,4-dinitrophenylhydrazine(DNPH) in silica gel column, which could react quickly withcarbonyls to generate DNPH derivatives. Then these derivatives were determined by HPLC.Then, the method was used for sampling and analyzing carbonyls in the atmosphere of PearlRiver Delta. Their concentrations and spatial-temporal distribution were studied in full-scale.In these studies, main conclusions were gained as following:1. Self-made cartridge successfully, collected carbonyls in the air, the average recovery ratios wereover 97.35%. The Self-made cartridge could acquire comparably effect as commercial cartridge, and belower sample cost consumedly.2. The concentration of formaldehyde and acetaldehyde were 7.75μg/m~3 and 8.18μg/m~3, whichwere respectively higher than other aldehydes compounds in the atmosphere of Pearl River Delta,and acetone was 12.06μg/m~3 higher in ketones compotmds. The concentrations of otherscarbonyls were very low. Compared with the data from other studies on urban areas worldwide,the carbonyls in the atmosphere of PRD were over middle level.3. The even concentration of carbonyls in daytime was higher than what at night, it reachedtiptop during from middy to 4 p.m and reach undermost at 4 a.m. The concentration of carbonylsat ground site was higher than 7th and 15th floor site, but the concentration at 7th sites was asmuch as 15th floor.4. From the ratio of formaldehyde/acetaldehyde which was 0.97, we concluded that anthropogenicemissions was the major source in the atmosphere of the Pearl River Delta, and the plant alsocould release lots of carbonyls from the ratio of acetaldehyde/propanal which was 8.51. Good correlations was found between formaldehyde, acetaldehyde, propanal and other carbonyls compounds,that concluded these compounds had common sources, but the correlations betweencrotonaldehyde and others was bad.5. The concentration of acetaldehyde was higher than formaldehyde at roadside air in Guangzhou,because the usage of the gasoline that mixed with ether and MTBE caused a great deal ofacetaldehyde. Both formaldehyde/acetaldehyde and acetaldehyde/propanal were low, whichexpressed that the main source of carbonyls at roadside air of Guangzhou was the motorvehicular.