11640
Quinones present in the traffic - related PM are hypothesized to contribute to these harmful effects through reactive oxygen species ( ROS ) generation .
 Chemical: Quinones; Chemical: oxygen
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: Quinones; Chemical: oxygen