12844
PC2 and PC3 cluster American - and Virginia - blends , revealing inverse correlations : Nitrogen oxides and amino - or nitroso - aromatic compounds inversely correlate to either formaldehyde and acrolein , or benzo ( a ) pyrene and di - hydroxybenzenes .
 Chemical: Nitrogen oxides; Chemical: amino; Chemical: nitroso; Chemical: formaldehyde; Chemical: acrolein; Chemical: benzo ( a ) pyrene; Chemical: di - hydroxybenzenes
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: Nitrogen oxides; Chemical: amino; Chemical: nitroso; Chemical: formaldehyde; Chemical: acrolein; Chemical: benzo ( a ) pyrene; Chemical: di - hydroxybenzenes