Children are more vulnerable to the effects of air pollution because their lungs don't fully form until they are adolescents, the American Academy of Pediatrics noted.

The leading pediatricians group added that "because children spend more time outdoors than do adults, they have increased exposure to outdoor air pollution."

"If you live near a polluted area of a city, it's like the child is smoking," said best-selling author and pediatrician Bill Sears. "We all know what smoking does for the lungs."

City life is unhealthy in many respects, but this is completely intolerable.