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EPA Unmix 6.0 Model
Receptor models provide scientific support for current ambient air quality standards and for implementation of those standards by identifying and quantifying contributions for source apportionment. Ambient air quality data sets have been improving greatly due to more species being measured, species being stratified by particle size, and shorter durations of sampling. Receptor model algorithms have also improved greatly to take advantage of these higher quality data sets.
To ensure that receptor modeling tools are available for use in the development and implementation of air quality standards, the United States Environmental Protection Agency's Office of Research and Development (ORD) has and continues to develop a suite of receptor modeling tools that are freely distributed to the air quality management community.
EPA Unmix is one of the receptor models that ORD has developed. The user provides a file of sample species concentrations, which the model uses to calculate the number of sources types, profiles, relative contributions, and a time series of contributions. The algorithms used in EPA Unmix model to compute profiles and contributions have been peer reviewed by leading scientists in the air quality management community and have been certified to be scientifically robust.
EPA Unmix software program is a stand-alone product, meaning that it requires no other software and is self-contained. There is no need for a license and the program is available free of charge. The software is menu-driven, using Graphical User Interfaces, and therefore eases inputting of data, generating, evaluating, and exporting of results.
System Requirements:
The Unmix 6.0 model works on Windows 2000, Windows XP, and Windows Vista. The computer should have at least a 2.0 GHz processor and at least 512 MB of memory. MS Excel is required for saving and exporting output.
IMPORTANT: PLEASE REGISTER FIRST (link below) before performing the download.
Registration Form
Comments or questions on EPA Unmix 6.0 or problems with the download should be sent to NERL_RM_Support@epamail.epa.gov. We welcome comments that can be considered for future development.
The latest version of EPA Unmix is available for download. A user's guide is also provided.
Product available for download:
EPA Unmix 6.0 Software (90 MB)
EPA Unmix 6.0 Fundamentals & User Guide (PDF, 97 pages, 5.5 MB)
The U.S. EPA is currently working on updating EPA Unmix. This version will incorporate recently corrected and published results related to block length calculations and some changes in the way old edges were utilized to find new solutions. The updated version will be posted here some time in the near future. Please refer back to this website periodically to ensure that the most recent version of the model is used in your applications. Thank you.
NERL RM Support Team