[clairity]

anything not N₂, O₂, argon, or H₂O is possibly air pollution, though some things are more harmful than others. many mundane things indoors give off VOCs (volatile organic compounds), from couch cushions to stained/painted woodwork. carbon dioxide, carbon monoxide, and ozone are air pollutants too. then you've got particulates like soot, smog, dust, pet dander, fly ash, dust mites, mold spores, pollen, etc. and then anything that smells from candles, perfumes, and soaps to smoke from cooking is more pollution. and that's just the stuff in the air (much more of a risk to humans than airborne viruses btw).