VOA慢速英语:US Study Links Air Pollution to Autism

autism spectrum disorder - n. any of a group of developmental disorders (as autism and Asperger's syndrome) marked by impairments in the ability to communicate and interact socially and by the presence of repetitive behaviors or restricted interests

spectrum - n. a continuous sequence or range

fine particulate – n. very small solid material or liquid in the air

compelling – adj. capable of causing someone to believe or agree

ratchet up – v. to cause to move by steps or degrees -- usually used with up or down

confidence – n. the feeling of being certain that something will happen or that something is true

therapy – n. the treatment of physical or mental illnesses