Prepare the Brussels sprouts by cutting off any stems/ends, then cut into fourths. If leaves fall off in the process, keep those too as they will turn out very crispy and delicious.
Toss in the oil, aiming to very lightly coat all the sprouts.
Air fry at 356°F for 3 minutes. Then remove the tray and carefully toss, rotating the sprouts in the process.
Air fry an additional 3-4 minutes until very crispy. Squeeze fresh lemon juice over the fried sprouts and sprinkle on salt just before serving.