UV-absorption cross sections of benzaldehyde, ortho-, meta-, and para-tolualdehyde

Absorption cross-sections for benzaldehyde, o-tolualdehyde, m-tolualdehyde and p-tolualdehyde have been measured in the wavelength region 252–368 nm using two different systems (D2 lamp-diode array and D2 lamp-monochromator). In addition, cross sections at 253.7, 312.2 and 365 nm have been measured using a Hg pen ray lamp and were found in good agreement with those obtained using the D2 lamp-diode array system. The absorption spectra of the four aromatic aldehydes have been found to exhibit fine structures similarly to aromatic hydrocarbons. The calculated atmospheric photolysis lifetimes suggest that photolysis is a potentially important removal process for these aromatic aldehydes in the troposphere.