What happens if you breathe in a little bit of freon?

Breathing in a small, trace amount of refrigerant—commonly referred to as Freon or modern HVAC refrigerants like R-410A—in a well-ventilated area typically causes little to no immediate harm, though you may notice a faint sweet or chemical odor. However, inhaling concentrated refrigerant vapors in a confined, poorly ventilated space displaces oxygen and can lead to acute symptoms such as dizziness, headaches, nausea, throat irritation, coughing, and coordination loss, and severe exposure can cause cardiac arrhythmias or chemical asphyxiation. If you suspect a refrigerant leak in your home HVAC system, you should immediately ventilate the area by opening windows and doors, leave the space, and contact a licensed HVAC professional to locate and repair the leak. You can verify that the air is safe when gas detectors clear and rooms are fully aired out.