The UV absorption spectra of nopinone, myrtenal, ketolimonene, caronaldehyde and limononaldehyde were investigated in the spectral range 210-370 nm at 353 K using a D2 lamp coupled to a monochromator-PM. All the spectra show an important absorption band beyond 280 nm. Below 230 nm, a much stronger absorption band is also observed. The cross-section values reported in this work were used to estimate the lifetime of the studied compounds with respect to photolysis. Results suggest that photolysis is potentially an important process for the removal of these compounds from the troposphere.