G. I cannot detect the metallic smell from the MedKlinn Air+Surface Sterilizer anymore, has is malfunctioned?

Smell should not be used to determine the effectiveness of the device. Smell is very subjective and can vary from one location to another and at different times. A rough indication to determine if the device is operating is to detect hissing sounds from the unit. Place the unit next to your ear to detect the hissing sounds.