The major objective of the proposed research is to study the impact of early-life exposures to common urban pollutants on neurobehavioral development and asthma in a sample of children living in three low-income, minority communities of New York City (Central Harlem, Washington Heights and the South Bronx). Using a molecular epidemiologic approach with monitoring, biomarkers, and clinical assessments at serial time points, we will extend our study of African-American and Latina urban mothers and children in order to follow the cohort through child age 11 years to assess the longer-term impact of exposures on child health and developmental outcomes.