Nox

he grew up in the toxic sewers beneath holocity. "sewers". the factories dump toxic waste underground that most civilians don't know about in their above ground paradise.

he fell into the sewer water as a child and it altered his physiology. he is now irradiated. he had to grow up far into the sewer tunnels with other untouchables to avoid making others sick. the radiation causes his lungs to be so bad he breathes out noxious fumes. he has to wear a gas mask around other people, with the filters inverted of course. they don't last long, though.
 from an underground edge of life boy to a deeproots life maintaining the inner waste dUmp.