This page describes the revisions and updates made to the CO-Benefits Risk Assessment (COBRA) Screening Model since October 2017.

May 30, 2018

EPA released version (3.2) which includes a new feature and minor enhancements, including:

1. A function to import results from EPA’s AVERT tool. EPA’s AVoided Emissions and geneRation Tool (AVERT) provides estimates of air pollution emission reductions from energy efficiency and renewable energy projects, programs, and policies. The latest version of AVERT (v2.0) allows users to export the results of the tool in a format that can easily be imported into COBRA. The newly released version of COBRA (v3.2) now includes a button that users can click to import the county-level emissions results from AVERT directly into COBRA. This new feature will allow easier screening-level analyses of the public health benefits of emission reductions from energy efficiency or renewable energy projects, programs, and policies.
    
2. Results in 2017 U.S. dollars. The monetized health benefits results from COBRA are now presented in 2017 U.S. dollars. In the previous version of COBRA (v.3.1), the results had been presented in 2010 U.S. dollars.

March 9, 2018

EPA released version (3.1) which includes a correction and minor enhancements, including:

1. A corrected set of calibration factors for 2017. COBRA 3.0 included incorrect factors that calibrate modeled data to actual monitored data for 2017 and, as a result, the estimated change in air quality was lower than it should have been for runs using the 2017 baseline. This also means that the estimated health benefits were lower than they should have been. The difference varies for different parts of country, but in some areas the benefits could be half of what they should be. Previous versions of COBRA (e.g. COBRA v2.71) did not have this error.  
2. Minor user enhancements to the interface and for batch mode operation. Minor adjustments were made to the interface, including rearranging the “Create Emissions Scenario” screen so that all of the user options are displayed on the screen without having to scroll to see them, and a bug was fixed that was causing COBRA to crash for some users when running in “batch mode.”

October 2, 2017

EPA released version (3.0) which includes several enhancements, including: 

1. An improved user interface with more flexible mapping functionality.
   1. With this version of COBRA, users can: customize the map color scheme, modify map interval breaks, explore data geospatially by selecting for specific attributes, and export maps for use in GIS programs.​
       
2. New features that enable advanced users to import custom baseline and scenario emissions files, population datasets, incidence datasets, health effect functions, and valuation functions.
   1. This functionality makes it possible to use COBRA for years other than the preloaded 2025 baseline.
       
3. An additional analysis year, 2025, so for each COBRA run, users can now select the previously available 2017 baseline or the newly added 2025 baseline. Sources of the new 2025 data include:  
   1. ​Emissions data: The COBRA 2025 emissions baseline uses emissions data from EPA’s 2011 Version 6.2 Air Emissions Modeling Platform (2011v6.2 platform) to forecast ambient 2025 PM_2.5 levels. 
   2. Population data: COBRA uses 2025 population projections based on US Census of Population and Housing 2010 and economic forecasting models developed by Woods & Poole (2012). 
   3. Incidence data: COBRA 2025 baseline mortality incidence is based on 2025 national-level Census mortality rate projections. 
   4. Valuation data: For consistency with the 2025 COBRA emissions baseline year, all unit values were adjusted for historical/projected growth in real U.S. income between the year of the original unit value estimate and 2025. The 2025 health values, like the 2017 values, are expressed in terms of 2010 U.S. dollars

       (Note: the 2017 baseline remains unchanged from version 2.71)