Semina: Ciências Exatas e Tecnológicas (Sep 2010)
Atmospheric formaldehyde and acetaldehyde at the campus University of Hiroshima, Japan
Abstract
Ambient levels of formaldehyde (HCHO) and acetaldehyde (CH3CHO) were measured at Hiroshima (Japan) during spring and summer of 2005. Measurements of O3, NOx, and SO2 were simultaneously conducted, in an attempt to identify temporal profiles and sources for these aldehydes. Atmospheric aldehydes were collected using C18 silica gel cartridges coated with an acidic solution of 2, 4-dinitrophenylhydrazine (2,4-DNPH) and analyzed by high performance liquid chromatography with UV/VIS detection adjusted to 360 nm. Summer concentrations were higher than spring levels. FA concentrations during spring period ranged from 0.50 to 1.05 ppb and AA concentrations ranged from 0.17 to 1.31 ppb; during summer their concentrations ranged from 1.55 to 4.12 ppb and 0. 34 to 2.03 ppb. Average FA/AA in spring and summer were 3.09 and 3.72 suggesting biogenic emissions of aldehydes. The levels of FA and AA, their temporal variations, and their concentration ratio (FA/AA) indicated that photochemical reactions contributed significantly to the formation of atmospheric aldehydes at the study site.
