Children are closest to the ground, where most air pollutants are concentrated. Children are most vulnerable to toxic chemicals because their brains and other organs are still developing and because they have inadequate immunologic and other defenses against toxic chemicals and metals. Children of parents exposed to certain pesticides and chemicals are more likely to have birth defects or to develop cancer during childhood. The incidences of brain cancer and leukemia have risen in children over the past two decades. Frequent pesticide use around the home is associated with an increased incidence of brain cancer in children.
Toxic chemicals can affect thyroid hormones, which control early brain development.
Exposure to air toxics can lead to neurobehavioral disorders, including increased aggression and antisocial tendencies. David Marrack, M.D., in his article on airborne particulate matter, makes a strong case that toxic chemicals are significantly underreported because current monitoring only measures chemicals in their gaseous phases, whereas most airborne toxic chemicals exist much of the time in a particle phase or adhered to various fine particulates in the air. When toxic chemicals are carried into the lungs by tiny particles, their toxic effects are greatly enhanced. In adults, changes in fertility are the most noted response. In fetuses and young children, who are far more sensitive, these chemicals can disrupt neurological, reproductive, and other development.