Effects of prenatal exposure to PM2.5 and its composition on cognitive and motor functions in children at 12 months of age: The Shanghai Birth Cohort Study

•Prenatal PM2.5 composition exposure was estimated in China with severe pollution.•Infant cognitive and motor functions in five domains were tested at 12 months by ASQ.•The effects of composition-specific PM2.5 were further evaluated.•PM2.5 compositions were negatively associated with ASQ scores in all five domains.•All PM2.5 compositions except OM were associated with lower problem-solving scores.