Co-Benefits Risk Assessment (COBRA) Screening Model

A Screening Tool That Estimates Health Effects

• Basic Information
• How COBRA Works
• Related Documents
• Request a Copy

Basic Information

Policies that reduce air pollution may also achieve other benefits, including an improvement of air quality and the avoidance of both the negative health effects associated with poor air quality and their respective economic costs. Understanding these co-benefits can help state and local governments enhance the benefit side of the cost-benefit equation when considering different policies.

EPA's Co–Benefits Risk Assessment (COBRA) model is a screening tool that helps state and local governments:

• Estimate the air quality, human health, and related economic co–benefits of clean energy policies or other actions that potentially reduce air pollution
• Visually present information about these multiple benefits in colorful, easy–to–interpret maps
• Quickly and inexpensively narrow a long set of promising policy options to a smaller list that can be evaluated using more sophisticated air quality models

The COBRA screening model is a stand–alone Windows application that enables policy analysts to quickly obtain a first–order approximation of the costs and benefits of different emission scenarios and to compare outcomes in terms of changes in ambient particulate matter (PM) concentrations, related health effects, and monetary impacts. It is designed to allow users to quickly and easily analyze the health effects of changes in emissions of PM, as well as pollutants associated with the secondary formation of PM (sulfur dioxide [S0₂], nitrogen oxides [NO_X], ammonia [NH₃], and volatile organic compounds [VOCs]), at the county, state, regional, or national level. COBRA presents these estimated county-level health impacts in both tables and maps.

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How COBRA works

1. The model contains detailed emission estimates for the years 2010 and 2015, developed by the U.S. EPA. Before running a scenario, users must select one of these years as the baseline for their scenario.
2. Users can create their own scenario by specifying increases or decreases to the emission estimates specified by the baseline. Emissions in the model include PM_2.5, S0₂, NO_X, NH₃, and VOCs. Emission changes can be entered at the county, state, or national levels, and outcomes can be modeled nationwide or for smaller geographic areas.
3. The model uses a reduced form air quality model, the Source-Receptor (S–R) Matrix, to estimate the effects of the user–specified emission changes on ambient PM.
4. Using a range of health impact functions and dollar values that EPA used in developing the Clean Air Interstate Rule, the model translates the ambient PM changes into human health effects and monetizes them.
5. Users can view the results in tabular or geographic form.

Note: COBRA does not replace more sophisticated analyses. COBRA serves as a preliminary screening tool to identify those scenarios that might benefit from further evaluation with more sophisticated air quality modeling approaches that are currently available.

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Related Documents

User Manual

Download the manual and appendices for COBRA:

• COBRA Manual (PDF) (137 pp, 4.7M) – revised 12/17/2010

Presentations & Related Materials

View an informative presentation and flyer about COBRA and its capabilities:

• The Co-Benefits Risk Assessment (COBRA) Screening Model (PDF) (14 pp, 804K)
• EPA's Co-Benefits Risk Assessment Model (PDF) (2 pp, 134K)

Sample COBRA Analyses

Following are a few examples of the types of analyses conducted using COBRA:

• Economic Benefits of Colorado BART Controls (PDF) (20 pp, 97K)
• Quantifying the Efficiency and Equity Implications of Power Plant Air Pollution Control Strategies in the United States

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Request a Copy

Download or Request COBRA

To obtain a copy of the COBRA model, either by mail or by download, please fill out the form below, choosing the preferred method for receiving the model. Users must have at least 2 GB free hard drive space and 256 MB of RAM.

EPA requests contact information to better support users and send occasional e-mails when the model is updated.

For More Information

For more information, contact Denise Mulholland (mulholland.denise@epa.gov) at 202-343-9274.

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