pollutant; environmental pollutant
Refers to substances that cause environmental pollution, especially in the context of public hazards (公害).
Pollutants discharged from factories have become a problem.
Regulations on environmental pollutants have been tightened in this area.
汚染物質 is a more general term for any contaminant or pollutant, while 公害物質 specifically refers to substances causing public nuisance or environmental pollution in a legal/social context.
Compound of 公害 (public nuisance, pollution) and 物質 (substance, matter).