Apartment is overrun with these gnats or gnat-like things out of nowhere

Does anyone know what these are or where they could be coming from? I wish the picture was better but this is the best I've got. They're about the size of tiny black mustard/poppy seeds until you look closely. They're all over the dining room and kitchen of my mom's apartment right now. She's got two of those zapper things out and my dad claims they're zapping 20-30 an hour (not sure if thats' an exaggeration) and it doesn't seem to be reducing their numbers. My mom poured boiling water and stuff down the drain in case they're coming from there but any guidance would be appreciated!