In connection with investigations of the ciliostatic effect of tobacco smoke, aldehydes have been of special interest as many of them have an irritating effect on the tracheal mucosa. A comparison of the ciliostatic effect of formaldehyde, acrolein, acetaldehyde, crotonaldehyde, and methacrolein shows that there are significant differences between the substance's regression lines. Formaldehyde seems to be the most toxic substance followed by acetaldehyde and acrolein. Crotonaldehyde and methacrolein have the weakest slope. The technique for observing the tracheal ciliary activity is the in vitro technique which has been used in many other investigations.
Dalhamn T, Rosengren A. Effect of Different Aldehydes on Tracheal Mucosa. Arch Otolaryngol. 1971;93(5):496–500. doi:10.1001/archotol.1971.00770060742011