Why is my dog squinting/closing his eyes?

Just started last night. I figured he was just tired of something. It didn't start until we started frying up some spam. This morning when I got home from work he greeted me like normal. I was putting groceries away so I wasn't paying much attention to his face but when I was cooking something in the air fryer I noticed he began doing it again. I figured maybe cooking fumes started this but even after half an hour of nothing being cooked he's still doing this. When hes in a different room from the kitchen he stops. Should I be worried?