Based on the information provided, what best describes the current understanding of air pollution and its potential link to autism spectrum disorder (ASD)?
O Children with a specific gene mutation are guaranteed to develop ASD if exposed to air pollution.
O There is conclusive evidence that air pollution directly causes ASD in all children.
O Living near a freeway during pregnancy has no impact on a child's risk of developing ASD.
O Studies suggest early-life exposure to air pollution might increase the risk of ASD, but other factors likely play a role.