CDC Attempts to Track Health and Pollution Connections

The Centers for Disease Control and Prevention (CDC) recently launched a website to allow the public to track environmental and public health information. The new National Environmental Public Health Tracking Network is intended to be a dynamic Web-based tool for tracking and reporting environmental hazards and the health problems that may be related to them. The tracking network offers information on several environmental hazards and health conditions, such as asthma, cancer, and certain air and water contaminants.

The CDC laid the foundation for the tracking network through grants to health departments in 16 states and New York City. The local tracking networks report their data to the national network, allowing researchers and the public to monitor and identify trends in environmental public health data.

CDC is working with the U.S. Environmental Protection Agency, the U.S. Geological Survey, the National Cancer Institute, and the National Aeronautics and Space Administration to share data and develop the tracking network. The CDC also consults with academic and nonprofit stakeholders such as researchers at Tulane University and the University of California, the American Lung Association, and the American Public Health Association.

Although a comprehensive online tool allowing the public to simultaneously track environmental pollution and trends in public health is sorely needed, the CDC’s new effort represents only an initial step toward such a tracking system. CDC officials acknowledge some of the limitations to the new tracking network and say that many will be addressed over time.

According to the CDC and the Pew Environmental Health Coalition, a national public health tracking network will serve several vital functions that currently are not available. CDC and its federal and state partners intend for the network to improve scientists’ ability to assess the connection between environmental pollution and its effect on health, as well as assess unusual trends and events to determine which communities may be at risk. County-level data are intended to aid residents seeking information about conditions such as asthma or the presence of air contaminants in their communities. The public and government officials could also evaluate the effectiveness of pollution abatement policies, improving the accountability and efficiency of the programs.

Through the state tracking programs, the CDC collects information on non-infectious health conditions and diseases, such as asthma and leukemia; chemicals or other substances in the environment, such as air pollution and water contaminants; and the amount of a chemical in a person’s body, such as blood lead levels.

The health data tracked are asthma, cancer, carbon monoxide poisoning, childhood lead poisoning, and heart attacks. CDC eventually plans to provide data on reproductive and birth outcomes and birth defects. Environmental data being tracked include carbon monoxide, ozone, and particulate matter levels in air, as well as contaminants in well water and municipal water.

The tracking network currently draws on data collected by CDC-funded programs in California, Connecticut, Florida, Maine, Maryland, Massachusetts, Missouri, New Hampshire, New Jersey, New Mexico, New York State, New York City, Oregon, Pennsylvania, Utah, Washington, and Wisconsin.

Numerous missing data sets currently weaken the usefulness of the site. For example, a search for childhood leukemia cases finds data from only eight states, and only years 2001 through 2005 are available. Such incomplete geographic and chronologic ranges severely limit the ability to identify trends and connect health impacts to environmental damages. Few data sets on the website contain information from all states or even a large majority of states. For instance, not all states provide data on cancer, or the same types of cancer, making state comparisons impossible. Pennsylvania is missing data on asthma tracking, and only three states are reporting on carbon monoxide emergency room visits. Similar data gaps occur among the environmental data sets.

The tracking network website demonstrates the difficulties of combining numerous different data sets into a useable, easy-to-understand format. Several federal agencies collect and process data before contributing it to the network. As well, the 16 states and New York City track data independently. Coordinating all these types of data into one accessible, searchable database is a large undertaking, and the CDC is only beginning the process.

Among the website’s strengths, it provides substantial definitions and documentation for the data, including how they were collected, what the limitations are, and to a lesser extent, how the data may be used. For example, the website describes the significance of tracking hospital admissions for asthma using a standardized method, claiming it allows for the monitoring of trends over time, identification of high-risk groups, and aids in asthma prevention, evaluation, and program planning efforts.

Searches are conducted by selecting options from several drop-down lists and check boxes. Search results are depicted in tables, graphs, and color-coded map formats, with the maps showing state- and county-level information.

The new site does not offer the user the ability to overlay one data set with another geographically. For example, a user cannot map asthma data overtop data on air pollution over time. Another significant weakness is the fact that raw data cannot be downloaded from the website, nor can the graphs, tables, and maps be downloaded in any format. The printing capabilities are also limited, and it is not possible to print the search results using certain Internet browsers. Officials at CDC recognize that users will need to download the data into formats that allow greater flexibility, such as into spreadsheets, and stated that they are developing such capabilities.


The CDC plans to expand the tracking network to all 50 states and to track additional environmental hazards and health conditions to build a more complete picture of environmental health. The agency may get some help if pending legislation in Congress is successful.

Congress is involved in the effort to track the health consequences of environmental contaminants. House Speaker Nancy Pelosi (D-CA) cosponsored with New York’s Rep. Louise Slaughter (D) a bill that would establish a national environmental health tracking program and provide greater funding for CDC’s biomonitoring efforts.

According to the Speaker’s office, "The network will coordinate national, state and local efforts to inform communities, public health officials, researchers and policymakers of potential environmental health risks, and to integrate this information with other parts of the public health system."


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