pollution vs dirtiness

pollution and dirtiness both are nouns.

Word	Noun	Adjective	Verb	Adverb
pollution	Yes	No	No	No
dirtiness	Yes	No	No	No

As nouns, dirtiness is a hypernym of pollution; that is, dirtiness is a word with a broader meaning than pollution:

Other hypernyms of pollution include uncleanness.

pollution (noun)	dirtiness (noun)
the act of contaminating or polluting; including (either intentionally or accidentally) unwanted substances or factors	obscenity in speech or writing
undesirable state of the natural environment being contaminated with harmful substances as a consequence of human activities	the state of being unsanitary
the state of being polluted	the state of containing dirty impurities