Using nitrous oxide cartridges is not a new phenomenon nor is it illegal, but from being associated with big cities until recently, it has thus spread to smaller cities as well.

- You might think that it is harmless because nitrous oxide cartridges are used in healthcare, but the nitrous oxide used in healthcare is mixed with oxygen to reduce the risk of oxygen deficiency, says Thomas Hoffmann, safety manager in Köping Municipality.

Inhaling pure nitrous oxide can sometimes cause damage to the vocal cords, nose and trachea, but you can also risk unconsciousness due to the lack of oxygen.