Climate and Energy Resources for State, Local and Tribal Governments

Co-Benefits Risk Assessment (COBRA) Screening Model

Updated June 2015

A tool that estimates the health and economic benefits of air quality policies

Health and economic benefits of policies that affect air pollution

Clean energy policies that reduce or avoid air pollution can enhance air quality and improve peoples’ health and quality of life. For example, exposure to air pollution from fossil fuel-based energy can exacerbate respiratory diseases, like bronchitis and asthma, and cause heart attacks and premature death. Beyond the physical health effects, pollution-related illnesses impose other ‘costs’ on people, such as lost wages or productivity when someone has to miss work or school, the costs of medical treatment and outdoor activity restrictions when air quality is poor.

Calculating the value of clean energy policies such as energy efficiency or fuel switching, can help state and local governments consider both the costs and benefits of policy choices and support a balanced decision-making process.

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What is COBRA?

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

  • Estimate and map the air quality, human health, and related economic benefits (excluding energy cost savings) of clean energy policies or programs.
  • Approximate the outcomes of clean energy policies that change emissions of particulate matter (PM2.5), sulfur dioxide (S02), nitrogen oxides (NOX), ammonia (NH3), and volatile organic compounds (VOCs) at the county, state, regional, or national level.

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Why use COBRA?

State and local governments can use COBRA to:

  • Better understand the potential for clean energy to enhance air quality, health, and social well being.
  • Design or select program options that maximize benefits.
  • Build support for clean energy investments based on the air and health benefits.
  • Narrow a list of policy options to those that should be evaluated using more sophisticated air quality models.
  • Present information about localized health benefits in easy–to–interpret tables and maps.
  • Support a balanced decision-making process that considers both the potential costs and benefits of policy options.

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

The presentation below provides more detail on why energy choices matter, ways you might use COBRA and an example of how estimating air and health benefits affected the benefit-cost ratio for two specific clean energy technologies.

Learn more:

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Who should use COBRA?

  • Analysts looking to improve their understanding of the air, health, and related economic benefits of clean energy or other policies that reduce emissions.
  • Environmental agencies interested in reviewing many options to identify policies that maximize health and economic benefits.
  • Energy officials who want to estimate and promote the air, health and economic benefits of their energy efficiency or renewable energy policies.
  • Transportation planners interested in understanding the air quality, health and related economic impacts of policies that affect air pollution, such as fuel switching or VMT reduction initiatives.

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How does COBRA work?

  1. COBRA contains detailed emission estimates of PM2.5, SO2, NOX, NH3, and VOCs for the year 2017 as developed by the U.S. EPA. Users create their own scenario by specifying increases or decreases to the baseline emission estimates. Emission changes can be entered at the county, state, or national levels, and outcomes can be modeled nationwide or for smaller geographic areas.
  2. COBRA uses a reduced form air quality model, the Source-Receptor (S–R) Matrix, to estimate the effects of emission changes on ambient PM.
  3. Using an approach to estimating avoided health impacts and monetized benefits that is generally consistent with EPA practice, the model translates the ambient PM changes into human health effects and monetizes them.
  4. Users can view the results in tabular or geographic form.
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How to Run Scenarios in COBRA

COBRA allows you to estimate the impact of a change in air pollution resulting from a new policy, such as a clean energy policy, or a major fuel switching investment by a large pollution source. The Quick Start Tutorial below gives step-by-step instruction on how to estimate the potential air, health and related economic benefits from two clean energy policies that can affect emissions, including a renewable energy target or renewable portfolio standard and an energy efficiency building retrofit program and a program intended to reduce vehicle miles travelled.

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Analyses that used COBRA

Following are a few examples of ways COBRA has been used:

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Download COBRA

Please click here to download the COBRA model.