Download Human Exposure Model (HEM)
For general information and documentation on HEM, please see the HEM page.
HEM4.2
1. Installation Instructions
- Hardware/Software Requirements. You can use HEM4.2 on any Windows™-based personal computer running Windows 98™ or later. Disk space requirements will depend on the number of census and meteorological files that you use. The zipped files of nationwide census and meteorological data are approximately 414 megabytes (MB). If using HEM4.2 to model only plants in a single state, then only the census and meteorological data for that state need to be extracted from the zip file, and the model would require much less disk space. To use all the nationwide Census and meteorological files, 3.3 gigabytes of disk space are needed. The model also will need a minimum of 8 gigabytes of RAM.
- Download documentation files from HEM home page, and review information on installing and configuring HEM4.2.
- Download the HEM4.2 zip file . (See Section 2 below).
- Select the directory into which to install HEM4.2 and unzip/extract the contents into that directory. The basic files needed to run HEM4.2 will be placed in that directory. A number of subdirectories will also be created.
- To complete the installation of HEM4.2, the Input Files provided in Section 3 below must be downloaded to your PC. Each .ZIP file must be unzipped, and the contents placed in a particular subdirectory of the HEM4 installation directory. Place the Toxicity Value Files in the "resources" subdirectory (HEM4\resources), the Census Files in the Census subdirectory (HEM4\census), and the Meteorological files in the met data subdirectory (HEM4\aermod\MetData).
2. Software available for download:
Please read installation instructions below before installing files. The HEM4.2 source code is also available.
3. Input Files for HEM4.2
Please read installation instructions above before installing files.
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Toxicity Value Files
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HEM Toxicity Value files (zip) (updated September 2024) - This .ZIP file must be unzipped, and the contents placed in the "resources" subdirectory (HEM4\resources).
These include a set of acute and chronic dose-response values compiled by OAQPS for purposes of RTR screening-level analyses; for some chemicals, surrogate values, identified based on policy considerations for these specific purposes, have been included. Users should review and confirm values are appropriate for their uses, making corrections or updates as needed prior to using. An accompanying file identifies the target organs associated with the chronic values.
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Census Files
- Nationwide 2020 Census files (zip) (updated September 2024) - Note: HEM4.2 was designed to use 2020 census files. This .ZIP file must be unzipped, and the contents placed in the census subdirectory (HEM4\census).
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Meteorological Files
- Nationwide Meteorological Data Files for 2019 (zip) (updated 2022) - This .ZIP file must be unzipped, and the contents placed in the met data subdirectory (HEM4\aermod\MetData).
HEM4.1
1. Installation Instructions
- Hardware/Software Requirements. You can use HEM4.1 (and the RTR summary programs) on any Windows™-based personal computer running Windows 98™ or later. Disk space requirements will depend on the number of census and meteorological files that you use. The zipped files of nationwide census and meteorological data are approximately 440 megabytes (MB). If using HEM4.1 to model only plants in a single state, then only the census and meteorological data for that state need to be extracted from the zip file, and the model would require much less disk space. To use all the nationwide Census and meteorological files, 2.2 gigabytes of disk space are needed. The model also will need a minimum of 132 megabytes of RAM.
- Download documentation files from HEM home page, and review information on installing and configuring HEM4.1.
- Download the HEM4.1 zip file . (See Section 2 below).
- Select the directory into which to install HEM4.1 and unzip/extract the contents into that directory. The basic files needed to run HEM4.1 will be placed in that directory. A number of subdirectories will also be created.
- To complete the installation of HEM4.1, the Input Files provided in Section 3 below must be downloaded to your PC. Each .ZIP file must be unzipped, and the contents placed in a particular subdirectory of the HEM4 installation directory. Place the Toxicity Value Files in the "resources" subdirectory (HEM4\resources), the Census Files in the census subdirectory(HEM4\census), and the Meteorological files in the met data subdirectory (HEM4\aermod\MetData).
2. Software available for download:
Please read installation instructions below before installing files. The HEM4.1 source code is also available.
3. Input Files for HEM4.1
Please read installation instructions above before installing files.
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Toxicity Value Files
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This .ZIP file must be unzipped, and the contents placed in the "resources" subdirectory (HEM4\resources).
These include a set of acute and chronic dose-response values compiled by OAQPS for purposes of RTR screening-level analyses; for some chemicals, surrogate values, identified based on policy considerations for these specific purposes, have been included. Users should review and confirm values are appropriate for their uses, making corrections or updates as needed prior to using. An accompanying file identifies the target organs associated with the chronic values. -
These files are available via link in section 3 of HEM4.2 above.
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Census Files
- Nationwide 2010 Census files (zip) (updated March 2023) -Note: HEM4.1 was designed to use 2010 census files. This .ZIP file must be unzipped, and the contents placed in the census subdirectory (HEM4\census).
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Meteorological Files
- These files are available via link in section 3 of HEM4.2 above. This .ZIP file must be unzipped, and the contents placed in the met data subdirectory (HEM4\aermod\MetData).