Also question is, do gas fireplaces smell?
In fact, a faint gas smell is an unavoidable consequence of using gas fireplace logs. In a gas ventless fireplace, oxygen is provided by the air in your home. If that air contains impurities, those impurities are drawn in with the oxygen and can produce odors which are amplified by the flame.
Correspondingly, are fumes from gas fireplace harmful?
Gas fireplaces are generally considered cleaner than traditional wood-burning fireplaces, but they can also pollute indoor air quality if not properly vented. Toxic gasses emitted include deadly carbon monoxide and nitrogen dioxide -- a gas particularly harmful to those with asthma.
YES, GAS FIREPLACES ARE ONE POTENTIAL CAUSE OF CARBON MONOXIDE POISONING. An improperly maintained or ventilated gas fireplace, however, can result in incomplete combustion, creating carbon monoxide, and causing this toxic gas to linger, putting those inside at risk of carbon monoxide poisoning.