Abstract: The invention is concerned with a process for counteracting smoke malodour wherein enclosed air spaces wherein smoke maladour is present, or substrates on which smoke malodour has deposited are brought in contact with one or more perfumery aldehydes of the class I according to general structure, wherein R1 and R2 each may be: hydrogen, alkyl, hydroxyl or alkoxy, or together may be methylenedioxy or with a perfume containing such aldehydes. Preferably the perfume also contains one or more perfumery aldehydes of class according to general structure, wherein R1 is a phenyl ring optionally substituted with an alkyl group, R2 represents hydrogen or both R2 taken together represent a double bond, and R3 is hydrogen or an alkyl chain with 1 to 6 carbon atoms. The smoke malodour counteracting perfumes preferably contain at least 3.5% w/w of class I aldehydes and at least 10% w/w of class II aldehydes.