environmental vs nonpolluting

environmental

adj
  • Pertaining to the environment. 

noun
  • Any factor relating to the physical environment in which hardware is operated, such as the room temperature or the number of racks used to hold equipment. 

nonpolluting

adj
  • Not polluting; environmentally friendly 

How often have the words environmental and nonpolluting occurred in a corpus of books? (source: Google Ngram Viewer )