22486
The Aryl Hydrocarbon Receptor ( AhR ) is a ligand mediated basic helix - loop - helix transcription factor of Per / Arnt / Sim family that regulates adaptive and toxic responses to variety of chemical pollutants including polycyclic aromatic hydrocarbons ( PAH ) and halogenated aromatic hydrocarbons , most notably 2 , 3 , 7 , 8 - tetrachlorodibenzo - p - dioxin ( TCDD ) .
 Chemical: Aryl Hydrocarbon; Chemical: polycyclic aromatic hydrocarbons; Chemical: PAH; Chemical: halogenated aromatic hydrocarbons; Chemical: 2 , 3 , 7 , 8 - tetrachlorodibenzo - p - dioxin; Chemical: TCDD
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: Aryl Hydrocarbon; Chemical: polycyclic aromatic hydrocarbons; Chemical: PAH; Chemical: halogenated aromatic hydrocarbons; Chemical: 2 , 3 , 7 , 8 - tetrachlorodibenzo - p - dioxin; Chemical: TCDD