28288
In order to develop a more robust health risk evaluation of TiO2 particle exposures , this review focuses on the following issues : A comprehensive evaluation of the existing animal and human health data is a necessary prerequisite for facilitating accurate assessments of human health risks to TiO2 exposures .
 Chemical: TiO2; Chemical: TiO2
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
 Entities: TiO2, TiO2 
Answer:
 Chemical: TiO2; Chemical: TiO2