Acetaldehyde is in tobacco smoke. Acetaldehyde is a hazardous air pollutant.
"Smoking and Tobacco Control." U.S. Department of Health and Human Services, Public Health Service, National Institutes of Health, National Cancer Institute. Risks Associated with Smoking Cigarettes with Low Machine-Measured Yields of Tar and Nicotine. 19 Nov. 2001: 179.http://cancercontrol.cancer.gov/brp/tcrb/monographs/13/m13_complete.pdf
"13th Report on Carcinogens (RoC): Acetaldehyde." National Toxicology Program, Department of Health and Human Services. 02 Oct. 2014. Web.https://ntp.niehs.nih.gov/ntp/roc/content/profiles/acetaldehyde.pdf