Some claims exist that the incidence of autism is higher for babies whose mothers spend time in ‘high traffic pollution’ areas compared to mothers who spend their pregnancy in cleaner air. In a recent study conducted by UCLA, air pollutant levels were measured for mothers who had children with autism and then compared to air pollutant levels in environments for mothers who had children without autism. This study found that babies who were exposed to higher levels of pollutants while in the womb had a 10% higher risk of autism than babies who had low levels of exposure; another finding from this study is that fine particulates had the strongest association with autism [15]