Description: This layer contains age-adjusted rates per 10,000 for asthma ED visits by census tract for the Maryland Environmental Public Health Tracking (EPHT) Portal. Data source: Maryland Health Services Cost Review Commission. The Maryland EPHT Portal (https://maps.health.maryland.gov/ephtportal/) assembles, integrates and makes available a variety of environmental hazard monitoring and human health indicator data. It offers tools that permit local, state and federal agencies to access and explore this data in order to plan, implement, and evaluate public health prevention and management strategies for environmentally-related diseases. The EPHT Portal also contains a variety of related information and resources targeted to healthcare and environmental stakeholders, educators and Maryland citizens in general.