Unknown. However, the smoke itself has an impact on the respiratory system of the newborn/2.
Yes. Crack affects the nervous system, sleep patterns, and therefore needed sleep for normal development of the child(especially the brain development) the younger the child the more the injury, if the exposure is continued intermittently, and even more of a danger if the exposure is constant.
Yes. Also tobacco and marijuana smoke. A child's body surface area is much smaller than an adult's, so concentrations of passively inhaled drugs in their blood and urine may be higher than in an adult. It's not good to smoke, shoot up or ingest drugs while caring for children; their risk of injury or death from accidents is just too high and it's not good for their lungs or their brains.