Data Download: Step 2
Table of Contents
- How to cite EQUATES data
- CMAQ data hosting platforms
- EQUATES CMAQ-ready input datasets
- EQUATES emissions summaries
- EQUATES emissions trends
- EQUATES CMAQ surface layer data
- EQUATES CMAQ 3D data
- EQUATES evaluation datasets
- EQUATES hourly surface and 3D datasets hosted on RSIG
- Measurement-Model "fused" CMAQ outputs
- Other CMAQ output datasets
How to cite EQUATES data
The following links provide the EQUATES Metadata, DOI for citation, and Data Use Policy.
Data License: There are no restrictions on the use of this data. Please see the U.S. EPA Data Licensing Information.
CMAQ Data Hosting Platforms
CMAQ input and output files are hosted on the CMAS Data Warehouse, an open-access database for collecting and disseminating meteorology, emissions and air quality model input and output. The CMAS Data Warehouse consists of a Google Drive as well as Amazon Web Services (AWS) storage through the AWS Open Data Sponsorship Program.
EPA also hosts EQUATES data on AWS Open Data storage and through its Remote Sensing Information Gateway (RSIG). In all cases, the CMAQ data is free to download to your local machine. The data on AWS can also be accessed using cloud-based high performance computing resources (e.g., AWS Elastic Compute Cloud, Microsoft Azure), avoiding the need to download the large datasets.
- EQUATES Data Dictionary for datasets available from the CMAS Data Warehouse and EPA AWS storage
- EQUATES Benchmark GitHub repository - includes directions for downloading EQUATES data from the CMAS Google Drive and a tutorial and sample run scripts for running CMAQ with EQUATES inputs
- Resources for running CMAQ on Amazon Web Services
- Accessing EQUATES hourly surface and 3D datasets hosted on RSIG
Please direct questions about the EQUATES datasets to the CMAS User Forum EQUATES category.
Model Domains
The EQUATES emissions, meteorology, and air quality modeling was performed on two domains: the Northern Hemisphere 108-km domain (Domain Name = 108NHEMI; Dimensions = 187 rows x 187 columns x 44 layers) and the contiguous U.S. (CONUS) 12-km domain (Domain Name = 12US1; Dimensions = 299 rows x 459 columns x 35 layers).
Note that CMAQ output data from EPA can be on different modeling domains. The ‘12US1’ domain that was used for the EQUATES project is larger than another standard EPA modeling domain referred to as ‘12US2’ which covers less of Canada and Mexico and has dimension 246 rows x 396 columns.
CMAQ-ready Input Datasets
The following table provides links to CMAQ input files: emissions, meteorology, boundary conditions and initial conditions. The emission datasets are provided in two different formats for different purposes and users. The first format, or inventory format, is a set of emissions and meteorology data suitable for input into the Sparse Matrix Operator Kernel Emissions (SMOKE) emission processor. The second format, or model ready format, provides the emission data either as inline or gridded file structures suitable for input to the CMAQ model. Both the inline and gridded files are standard input data structures readable by CMAQ and are compressed netCDF4 format.
Note about inventory vs model ready emission: The inventory emissions cannot be used to recreate the model ready emissions for several reasons. The inventory emissions only include U.S. anthropogenic sectors for the 12US1 modeling domain. Canada and Mexico fire and commercial marine vessel inventories are included, but other Canada and Mexico emissions are not included. Biogenics are not included since they are estimated online in CMAQ. In addition, the onroad emissions and scripts in the inventory packages are based on a nonpoint-style FF10 format to allow processing without running SMOKE-MOVES. Since EQUATES onroad emissions did use SMOKE-MOVES, the onroad emissions will be slightly different from those in the model ready package.
Note about data format: The EQUATES model inputs are netCDF-4/HDF5 compressed files to substantially reduce file sizes. Through testing at the EPA, we’ve noticed that certain simulations encounter model crashes from reading in large amounts of compressed netCDF data. A work around for those cases is uncompressing the data manually via nccopy 1 or m3cple (compiled with HDF5) before running the CMAQ simulation.
| Data Description | Domain (grid size) | Simulation Dates | File type (size for all years) | Google Drive Folder |
|---|---|---|---|---|
|
Inventory emissions (SMOKE inputs)* |
Contiguous US | Jan 1 - Dec 31 for years 2002-2019 |
netCDF (1 TB) |
INV emissions |
|
CMAQ-ready emissions inputs |
Contiguous US (12km) | Jan 1 - Dec 31 for years 2002-2019 | netCDF (2 TB) | Emissions input |
| CMAQ-ready meteorology inputs | Contiguous US (12km) | Jan 1 - Dec 31 for years 2013**-2019 | netCDF (16.8 TB) | Met input |
| CMAQ boundary condition (BC) files | 3D data at the 12US1 domain boundary | Jan 1 - Dec 31 for years 2002-2019 | netCDF (2.6 TB) | BC files |
| EQUATES restart files to be used as initial conditions (IC) | Contiguous US | Restart files are provided for the 1st and 15th day of each month for years 2002-2019 to allow for a 2-4 week ‘spin-up’ period | netCDF (277 GB) | IC files |
*Files and scripts for applying the Community Regional Atmospheric Chemistry Multiphase Mechanism (CRACMM) speciation to EQUATES onroad emissions are included with the INV emissions (EQUATES_2018_onroad_inv_CRACMM_addendum.zip).
**Only 7 years of EQUATES CMAQ-ready meteorology inputs are available at this time due to storage space limitations/cost.
2017 Model Inputs are also available from CMAS's AWS Open Data Program
| Data Description |
Domain (grid size) |
Simulation Dates | File type (size for all files) | AWS S3 bucket |
|---|---|---|---|---|
|
CMAQ-ready emissions, meteorology, boundary condition and initial conditions (restart) files |
Contiguous US (12km) | Jan 1 - Dec 31, 2017 |
netCDF (3.2 TB) |
CMAQ-ready inputs |
Emissions Summary Datasets
The EQUATES 2002-2017 emissions summary files are part of the CMAS Center Dataverse Repository for EQUATES. All emissions data are in US tons. The Dataverse repository includes a meta data file: README_EQUATES_v1.0_emissions_summaries.txt
| Data Description | File type (size for all years) | File name (Files are attached to the EQUATES Dataverse repository) |
|---|---|---|
| Annual total emissions for CONUS (not including offshore sources) for NOX, SO2, CO, PM2.5, PM10, VOC_regulatory1 , NH3_nofert2, NH3_fert3 for 2002-2017 based on the inventory (INV) emissions files | Zipped ASCII file (1.5KB) | EQUATESv1.0_INV_ emissions_annual_totals _by_pollutant.csv.gz |
| Annual total emissions summed over all grid cells overlapping CONUS including federal waters for NOX, SO2, CO, PM2.5, POC, PEC, VOC_regulatory, NMOG, NH3_nofert, NH3_fert for 2002-2017 based on the model ready (MR) emissions files | Zipped ASCII file (1.8KB) | EQUATESv1.0_MR_emissions _annual_totals_by_ pollutant.csv.gz |
| Annual total emissions summed over all grid cells overlapping CONUS including federal waters for NOX, SO2, CO, PM2.5, POC, PEC, VOC_regulatory, NMOG, NH3_nofert , NH3_fert for 2002-2017 by source category based on the MR emissions files | Zipped ASCII file (28KB) | EQUATESv1.0_MR_emissions_ annual_totals_by_source_ and_pollutant.csv |
| CMAQ 12US1 grid information including row/column, Lambert conformal projected x/y coordinates for grid cell centers, and longitude/latitude for the lower left and upper right corner of each grid cell | Zipped ASCII file (5.4MB) |
EQUATES_CMAQ_12US1_ grid_coordinates.csv.gz |
| Annual total gridded emissions for the 12US1 domain for 2002-2017 based on the MR emissions files for <pollutant> = NOX, SO2, CO, PM2.5, POC, PEC, VOC_regulatory, NMOG, NH3* | Zipped ASCII files (17MB per file) | EQUATESv1.0_<pollutant>_ 12US1_annual_emissions _2002-2017.csv.gz |
| Monthly total gridded emissions for the 12US1 domain for 2002-2017 based on the MR emissions files for <pollutant> = NOX, SO2, CO, PM2.5, OC, EC, VOC_regulatory, NMOG, NH3 | Zipped ASCII files (190MB per file) | EQUATESv1.0_<pollutant>_ 12US1_monthly_emissions _2002-2017.csv.gz |
1 Regulatory volatile organic compounds defined as in the Code of Federal Regulations, 40 CFR 51.100
2 Anthropogenic NH3 emissions excluding emissions from fertilizer which were calculated online in CMAQ
3 NH3 fertilizer emissions from agriculture, calculated online in CMAQ and post-processed to be included in these summary files
* Total anthropogenic NH3 emissions including emissions from fertilizer
EQUATES Emissions Trends
EQUATES emissions are a part of the EPA's Air Pollutant Emissions Trends Data which provides state level pollutant emissions from major source types for 1970 - 2022.
- Air Pollutant Emissions Trends Data website
- Documentation on the development of the Emissions Trends Data
- Explore air quality trends interactively with Our Nation's Air: Status and Trends Through 2021
Note that changes were made to EQUATES emissions for three specific source categories (livestock, fugitive dust, volatile chemical products) before they were incorporated into the Trends Data. These updated emissions are referred to as EQUATES 'version 1.1' and reflect methods improvements and bugfixes that were not available at the time the original 'version 1.0' emissions were processed.
CMAQ Surface Layer Estimates
Gridded model output datasets are provided for users who want to use CMAQ air quality estimates for regulatory or research applications (e.g., epidemiological studies, critical loads analysis), or model evaluation and development applications (e.g., diagnostic evaluation, reference data for sensitivity studies). Daily average surface concentrations for 14 species over the contiguous U.S. are provided in two file formats: netCDF and .csv. Annual total deposition maps for 22 species are provided as GeoTIFF files. The list of concentration and deposition species included in the model output datasets can be found in Tables 7 and 8 of the EQUATES Data Dictionary. CMAQ daily average 3D output over the Northern Hemisphere is provided for users who want to examine continental‐scale air quality trends or who want to create boundary conditions for any subset domain in the hemisphere (see the CMAQ IC/BC Tutorial on GitHub).
| Data Description | Domain (grid size) | Simulation Dates | File type (size for all years) | Google Drive Folder |
|---|---|---|---|---|
| CMAQ daily average surface concentrations for 14 chemical species | Contiguous US (12km) | Jan 1 - Dec 31 for years 2002-2019 | netCDF (48.6 GB) and ASCII (103 GB) | CMAQ Conc |
| CMAQ annual total deposition for 22 chemical species | Contiguous US (12km) | Jan 1 - Dec 31 for years 2002-2019 | GeoTIFF (29 MB) | CMAQ Dep |
CMAQ 3D Air Quality Estimates
We are transitioning to hosting more of our modeling datasets through Amazon Web Services (AWS) Open Data Program. The following 2018 and 2019 EQUATES 3D and column total datasets are saved in different AWS S3 buckets. The hourly and daily average 3D data are available for users who want to examine continental‐scale air quality trends. The daily average 3D output files can also be used to create boundary conditions for any subset domain in the hemisphere (see the CMAQ IC/BC Tutorial on GitHub).
| Data Description |
Domain (grid size) |
Simulation Dates |
File type (size for all files) |
Google Drive or AWS S3 bucket link |
|---|---|---|---|---|
|
CMAQ hourly 3D concentrations for 35 layers and 27 species |
Contiguous US (12km) | Jan 1 - Dec 31, 2019 |
netCDF (4.3 TB) |
12US1 CMAQ hourly 3D outputs (EPA AWS) |
|
CMAQ hourly column totals for 7 species: NO2, CO, SO2, HCHO, O3, JNO2, AOD550 |
Contiguous US (12km) | Jan 1 - Dec 31, 2019 |
netCDF (32.4 GB) |
12US1 CMAQ hourly column totals (EPA AWS) |
|
Hemispheric CMAQ daily average 3D concentrations for 44 layers and 260 species |
Northern Hemisphere (108km) | Jan 1 - Dec 31 for years 2002-2019 | netCDF (10.8 TB) | HCMAQ daily average 3D outputs *can be used to created CMAQ BCs (CMAS Google Drive) |
|
Hemispheric CMAQ daily average 3D concentrations for 44 layers and 260 species |
Northern Hemisphere (108km) | Jan 1, 2018 - Dec 31, 2019 | netCDF (1.2 TB) | HCMAQ daily average 3D outputs *can be used to created CMAQ BCs (CMAS AWS) |
|
Hemispheric CMAQ hourly 3D concentrations for 44 layers and 22 species |
Northern Hemisphere (108km) | Jan 1 - Dec 31, 2019 |
netCDF (1.1 TB) |
HCMAQ hourly 3D outputs (EPA AWS) |
|
Hemispheric CMAQ hourly column totals for 7 species: NO2, CO, SO2, HCHO, O3, JNO2, AOD550 |
Northern Hemisphere (108km) | Jan 1 - Dec 31, 2019 |
netCDF (8.3 GB) |
HCMAQ hourly column totals (EPA AWS) |
Evaluation Datasets
| Data Description | Simulation Dates | File type (size for all years) | Google Drive Folder |
|---|---|---|---|
| matched meteorological model output with surface observations for temperature, water vapor mixing ratio, wind speed and wind direction | Jan 1 - Dec 31 for years 2002-2019 | ASCII (4.7 GB) |
EQUATES - RSIG
EQUATES meteorology, air quality, and deposition data are hosted on the EPA's Remote Sensing Information Gateway (RSIG). RSIG provides a standalone application for subsetting and visualizing the hourly gridded model data and a web service for efficient transfer of large model datasets. EQUATES datasets are available for the Contiguous US (12km x 12km grid size and 35 vertical layers) and the Northern Hemisphere (108km x 108km grid size and 44 vertical layers).
Please direct questions about the EQUATES datasets to the CMAS User Forum EQUATES category. Questions about RGIG can be directed to RSIG Technical Support.
Accessing EQUATES data with the RSIG3D application
The RSIG3D interface allows a user to:
- Subset EQUATES data to a smaller spatial bounding box
- Select a specific 7-day interval between January 1, 2002 and December 31, 2017
- Aggregate the hourly data to daily metrics including daily mean, daily maximum, and maximum daily 8-hour average (all calculated in Coordinated Universal Time unless using the Local Standard Time data)
- Save the data in various formats (limited to 1 week of data)
We highly recommend watching the video tutorials available on the RSIG website to learn how to use various features of RSIG3D.
Directions for accessing EQUATES data on the RSIG3D application:
- Download and install RSIG3D from the RSIG website
- Launch the RSIG3D application by double clicking the RSIG3D executable
- Navigate to the
Datatab - Navigate to
Model 🠢 equates 🠢 conusfor gridded model data covering the Contiguous US, or - Navigate to
Model 🠢 equates 🠢 hemifor gridded model data covering the Northern Hemisphere - Within the
conusandhemimenus the model data have been grouped into several different categories described in the following table - After selecting a category users can select from a list of available model variables
- For model data in Local Standard Time, change Timebase in the Data tab from Hourly to Daily_LST then navigate to
Model 🠢 equates 🠢 conusfor gridded model data covering the Contiguous US - Metadata (variable definition, units, temporal coverage) is available by hovering your mouse over the variable name
| Model data category | Description |
|---|---|
| aconc | Hourly average surface concentrations and select meteorology variables (Coordinated Universal Time) |
| lstaconc | Hourly average surface concentrations and select meteorology variables (Local Standard Time) |
| conc | Hourly 3-D instantaneous concentrations |
| dep | Hourly cumulative surface deposition (dry and wet) |
| integrated | Hourly column-total concentrations (sum over all vertical layers) |
| metcro3d | Hourly 3-D meteorology variables except winds |
| metdot3d | Hourly 3-D horizontal wind components |
| wwind | Hourly 3-D derived vertical velocity |
Downloading EQUATES data with the RSIG web service
The RSIG web service can be used to obtain data from RSIG without having to use the RSIG3D application. The web service allows bulk data transfer of EQUATES data, e.g., hourly ozone data for an entire month. Users on a Linux system can use the cURL command-line tool.
For example, the following cURL command will download hourly ozone data for January 1-31, 2017 for a bounding box covering North Carolina as an I/O API formatted netcdf file, using data compression/decompression for faster downloads:
curl --silent --retry 0 -L --tcp-nodelay --max-time 0 'https://ofmpub.epa.gov/rsig/rsigserver?SERVICE=wcs&VERSION=1.0.0&REQUEST=GetCoverage&FORMAT=netcdf-ioapi&TIME=2017-01-01T00:00:00Z/2017-01-31T23:59:59Z&BBOX=-84.590000,33.220000,-74.730000,37.450000&COVERAGE=cmaq.equates.conus.aconc.O3&COMPRESS=1&' | gzip -d > EQUATES_ACONC_O3_201701_NC.nc
See the RSIG website for further examples and information on using curl commands to download EQUATES data: Downloading CMAQ files from RSIG
Measurement-Model "Fused" CMAQ Outputs
CMAQ output is often combined, or "fused", with observed air quality measurements to remove any consistent model biases prior to using the model predictions for a particular application. Below are examples of bias-corrected CMAQ outputs that are available to download. Note that many of these datasets are not part of the EQUATES project.
Ozone and PM2.5
- The Centers for Disease Control and Prevention (CDC) use spatially fused surfaces of ozone and PM2.5 provided by EPA that combine CMAQ output (versions 4.6 through 5.3, depending on the year) with ambient monitoring data to inform their National Environmental Public Health Tracking Network. View these fused air quality surfaces for 2002 - 2012 using the CDC Air Quality Data Explorer Tool or download the fused data through the EPA's Remote Sensing Information Gateway (RSIG).
Deposition
EQUATES (CMAQv.5.3.2)
- GeoTIFF files of precipitation and bias-adjusted CMAQ-predicted values of annual total deposition across the U.S. for 2002 through 2019 are available from the CMAS Data Warehouse Google Drive. These values were created using the EQUATES CMAQv5.3.2 simulations and include the bidirectional flux of ammonia. Total deposition values were developed by summing the dry and wet deposition in each grid cell. For these GeoTIFF files, the wet deposition component has been bias corrected using measured values from the National Atmospheric Deposition Program (NADP) and precipitation adjusted using the Parameter-elevation Relationships on Independent Sloped Model (PRISM) following the approach in Benish et al. (2022; https://doi.org/10.5194/acp-22-12749-2022)
ECODEP (CMAQv5.0.2)
- Shapefiles of CMAQ-predicted values of annual total deposition across the U.S. for 2002 through 2012 are available through our FTP server. These values were created using CMAQ v5.0.2 and include the bidirectional flux of ammonia. Total deposition values were developed by summing the dry and wet deposition in each grid cell. For these shapefiles, the wet deposition component has been bias corrected using measured values from the National Atmospheric Deposition Program (NADP) and precipitation adjusted using the Parameter-elevation Relationships on Independent Sloped Model (PRISM) following the approach in Zhang et al. (2019). Additional meta data is provided with the data files.
- The NADP Total Deposition Science Committee (TDEP) has created estimates of total deposition using a measurement-model fusion approach that relies on CMAQ model output and measured values from monitoring networks. For these files, the wet deposition values come from the NADP measurements and the PRISM model. The dry deposition values are from the fusion of CMAQ model values and observed concentration values. These data are provided as ESRI grid files and as image files.
Other CMAQ Outputs
The following datasets use older CMAQ versions. We recommend using data from the most recent CMAQ version when possible, however these older datasets may be helpful as a reference case or for comparing model evaluation across years and model updates.
| CMAQ Version | Data Type | Domain (grid size) | Vertical Layer(s) | Simulation Dates | Data Sharing Platform and Metadata |
|---|---|---|---|---|---|
| v5.2 | Hourly and Daily Output for 15 chemical species | Contiguous US (12km) | Layer 1 (surface) | Jan 1 - Dec 31 for years 2002-2014 |
CMAS Data Warehouse |
| v5.1 | Hourly and Daily Output for 15 chemical species | Contiguous US (12km) | Layer 1 (surface) | Jan 1 - Dec 31, 2013 |
CMAS Data Warehouse |
| v5.0.2 | Hourly and Daily Output for 15 chemical species | Contiguous US (12km) | Layer 1 (surface) | Jan 1 - Dec 31 for years 2002-2012 |
CMAS Data Warehouse |