A potential direct dissociation pathway is suggested through oxygen atom release from the energy-rich Criegee intermediate produced from ozonolysis of cycloalkenes. The yield of adipaldehyde from the ozonolysis of cyclohexene was independent of humidity; furthermore, the yield of pinonaldehdye from ozonolysis of a-pinene was independent of the presence of an OH scavenger. Excluding the production of dialdehydes as being mediated by either H2O or OH, a possible dissociation from the energy-rich Criegee intermediate involving the loss of an oxygen atom is suggested.