Important risk factors associated with sudden infant deaths include in addition to the prone position also other exogenous factors which influence the respiratory function of the infant, in particular during the first half of his life.The negative action of maternal smoking during pregnancy damages foetal development and the child can suffer damage also from cigarette smoke in the environment.The investigation indicates possible toxic effects of activated matrixins by nitrogen oxides in pulmonary tissue caused by their presence in the environment.

        Key words: metalloproteinases, detection of lung damage - sudden infant deaths