infection vs pollution

infection

noun
  • The act or process of infecting. 

  • A disease caused by a pathogen. 

  • An uncontrolled growth of harmful microorganisms in a host. 

  • A visible sign of such a disease, such as the suppuration of a wound. 

pollution

noun
  • Something that pollutes; a pollutant. 

  • Moral or spiritual corruption; impurity, degradation, defilement. 

  • Physical contamination, now especially the contamination of the environment by harmful substances, or by disruptive levels of noise, light etc. 

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