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A major class of chemicals found in tobacco smoke is formed by aldehydes , in particular formaldehyde , acetaldehyde and acrolein .
 aldehydes, formaldehyde, acetaldehyde, acrolein
Please list all entity words in the text that fit the category. Output format is "word1, word2". 
Option: Chemical 
Text: {0} 
Answer:
 aldehydes, formaldehyde, acetaldehyde, acrolein