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摘要
The concentration level of carbonyl compounds in Bangkok ambient air were measured in five roadside sites and five residential sites during July 2007 to April 2008. About 250 samples were collected and ten carbonyls were identified. Formaldehyde and acetaldehyde were the most abundant carbonyl compounds found in Bangkok ambient air. The ambient concentration of formaldehyde at the roadside areas in Bangkok during July 2007 to April 2008 ranged from 5.14 to 17.2 mu g/m(3) (average 11.53 mu g/m(3)) while, the ambient concentrations of formaldehyde in residential areas in Bangkok during the same period ranged from 3.06 to 19.9 mu g/m(3) (average 9.65 mu g/m(3)). The concentrations of acetaldehyde in roadside areas ranged from 1.59 to 7.95 mu g/m(3) (average 3.51 mu g/m(3)) while at the residential areas the concentrations of acetaldehyde during the same period ranged from 1.07 to 8.05 mu g/m(3) (average 3.11 mu g/m(3)). Other compounds showed low concentration. The concentrations of formaldehyde and acetaldehyde were low during the rainy season due to rain washout since these compounds are water soluble. The concentrations were high during the cold season due to stable conditions during these months. The concentrations slightly decreased during the summer due to photochemical reactions and photolysis under extreme temperature. Formaldehyde and acetaldehyde showed good correlation during 17:00 P.M. to 05:00 A.M. due to absence of solar radiation that may enhance photochemical reactions and mobile sources may be the sources of emission in the environment. It was also found that the concentrations of formaldehyde and acetaldehyde were low during the night time.
- 出版日期2011-3
