That is the food itself. Though it really depends on the method. Most cooking, including frying, won’t raise pm 2.5 levels.

But if something goes wrong and you can smell any kind of burning, then generally the levels will rise to between 150-500. I’m including small things, like a speck of food getting out of the fry pan and onto the burner. Or not enough oil in the pan, or anything producing a maillard reaction. The line between “nothing noxious” and “whoa that is dangerous” is very thing in my measuring experience. And the best way to deal it when it happens is opening windows. These should clear it out within 15 min or less in most cases.

Never had a gas stove so never tested for pm 2.5. Am guessing it is higher, and co2 as well.