Is the smell of growing unsmoked marijuana bad for a infant?

Hmmmm. Probably not as bad as having parents who smoke the marijuana around the infant, while they're supposed to be taking care of him/her. Relating with a baby -- sober -- helps him develop emotionally and intellectually. Very important to be clear yourself while parenting.
Probably healthful! The odor of cannabis plants come from terpenoids which have no known harmful effects. Quoting from http://www.Alternet.Org/drugs/those-pungent-smells-oozing-out-marijuana-buds-are-actually-giving-you-clues-about-what-their : "cannabis terpenoids and flavonoids may also increase cerebral blood flow, enhance cortical activity, kill respiratory pathogens, and provide anti-inflammatory activity.".