Pollutants may be material or immaterial (e.g. heat energy)

An environmental system process that results in the introduction of contaminants into an environment.

pollution

http://purl.obolibrary.org/obo/envo.owl

environmental_hazards

https://www.e3s-conferences.org/articles/e3sconf/abs/2020/77/e3sconf_ersme2020_04007/e3sconf_ersme2020_04007.html