Formaldeído e acetaldeído atmosféricos no Campus da Universidade de Hiroshima, Japão.

Abstract

Ambient levels of formaldehyde (HCHO) and acetaldehyde (CH₃CHO) were measured at Hiroshima (Japan) during spring and summer of 2005. Measurements of O₃, NO_x, 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.