 Smoking alters the transcriptome of the lung parenchyma; the expression levels of a panel of seven genes (KMO, CD1A, SPINK5, TREM2, CYBB, DNASE2B, FGG) are increased in the lung tissue of smokers.Second-hand smoke presents a known health risk, to which six hundred thousand deaths were attributed in 2004.It also has been known to produce skin conditions such as freckles and dryness.