Book excerpt: "America's Children and the Environment (ACE)" is EPA's report presenting data on children's environmental health. ACE brings together information from a variety of sources to provide national indicators in the following areas: Environments and Contaminants, Biomonitoring, and Health. Environments and Contaminants indicators describe conditions in the environment, such as levels of air pollution. Biomonitoring indicators include contaminants measured in the bodies of children and women of child-bearing age, such as children's blood lead levels. Health indicators report the rates at which selected health outcomes occur among U.S. children, such as the annual percentage of children who currently have asthma. Accompanying each indicator is text discussing the relevance of the issue to children's environmental health and describing the data used in preparing the indicator. Wherever possible, the indicators are based on data sources that are updated in a consistent manner, so that indicator values may be compared over time.