Check if gas is smelled.
The refrigerant of air conditioner does not have smell.
If you smell gas, open the window in the room and let some fresh air in immediately. Also, stop using electronic products during the time you smell gas.
Then check the gas pipe around the location.
If there is no problem, then you may check now the air conditioner.
Does the cold air come out from the air conditioner on Turbo (speed) mode?
Run the air conditioner a Turbo (speed) mode adn check if cool wind come out of the outlet to check that gas leaks from the air conditioner.
Keep the air conditioner working for 3- 5 minutes.
If the cold air comes out from the air conditioner on Turbo (speed) mode, the air conditioner is normal.
If the gas had leaked from the air condtioner, the cold air would not come out from the AC itself.
Clean the Dust Filter