Last Updated 2024-11-24
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EPA's Air Quality Time Series Project (EQUATES)

Data Dictionary

Summary

The EPA's Air Quality Time Series (EQUATES) project datasets include 2002-2019 emissions, meteorology, and air quality modeling of the contiguous US (CONUS) over the "12US1" 12-km domain and Northern Hemisphere over the "108NHEMI" 108-km domain. The datasets are publicly available through the EPA's Amazon Web Services (AWS) Open Data Sponsorship Program (ODP) and the CMAS Data Warehouse (consisting of a Google Drive and AWS ODP) to support numerous human health and ecological modeling endpoints, as well as model evaluation and development. The following sections describe the datasets, including the target audience for the data, the file type, data dictionary (when applicable), and the location of the files on the the EPA AWS Storage, CMAS Google Drive, and CMAS AWS Storage.

How to Cite EQUATES Data

DOI: https://doi.org/10.15139/S3/F2KJSK
Website: https://www.epa.gov/cmaq/EQUATES
Reference for EQUATES emissions: https://doi.org/10.1016/j.dib.2023.109022

EQUATES Modeling Domains

Figure 1. 108NHEMI Domain over the Northern Hemisphere: 187 rows x 187 columns x 44 layers
108NHEMI Domain over the Northern Hemisphere










Figure 2. 12US1 Domain over the CONUS: 299 rows x 459 columns x 35 layers
12US1 Domain over the CONUS












Note: CMAQ output data from EPA can be on different modeling domains.
The '12US1' domain above 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 396 rows x 246 columns.

EQUATES Inventory Emissions for CONUS (12US1 domain)

Purpose: For users who want to run SMOKE using EQUATES emissions files.
Location of Meta Data: EQUATES/SMOKE_INPUT/README_EQUATES_<date of last update>.txt
Units: All emissions data are in US tons.

Table 1

Data description File type (File size for all years) Location on CMAS Data Warehouse (File paths relative to this top level folder: CMAS Google Drive Link)
Year specific inventory emissions for 2002-2019 tarred and zipped netCDF files (880 GB) EQUATES/SMOKE_INPUT/< year(YYYY)> (1)/EQUATES_INV_YYYY_version1.0.tar.gz
Ancillary files needed for all years tarred and zipped netCDF files (11GB) EQUATES/SMOKE_INPUT/ancillary_data.tar.gz
Files and scripts for applying the Community Regional Atmospheric Chemistry Multiphase Mechanism (CRACMM) speciation to EQUATES onroad emissions zipped .txt and .csh files (486K) SMOKE_INPUT/EQUATES_2018_onroad_inv_CRACMM_addendum.zip Meta data: SMOKE_INPUT/README_ EQUATES_2018_onroad_inv_CRACMM_addendum.tx
Meta data: SMOKE_INPUT/README_ EQUATES_2018_onroad_inv_CRACMM_addendum.tx
Footnote:
(1) Four-digit year

EQUATES Model-Ready Inputs for CONUS (12US1 domain)

Purpose: For users who want to run CMAQ using EQUATES input data. 2002-2019 data are available on the CMAS Google Drive. CMAQ inputs for 2017 and MCIP outputs for 2002-2019 are also available on CMAS AWS Open Data Storage.
Location of Meta Data: EQUATES/CMAQ_12US1/INPUT/README_EQUATES_v1.0_modelready.txt
Units: Units for each variable are included in the meteorology, emissions, and CMAQ netCDF files.

Table 2

Data description File type (File size for all years) Data location Location on CMAS Data Warehouse (File paths relative to the top-level Google Drive or AWS link provided.)
CMAQ-ready meteorology inputs for 2013-2019 on Google Drive (note: 2002-2019 are available on AWS Open Data Program) (2) CMAS Google Drive tarred netCDF files (16.8 TB) EQUATES/CMAQ_12US1/INPUT/< year>/met/mcip_v51_wrf_v411_noltng/< month> (3)
CMAQ-ready emissions inputs for 2002-2019 CMAS Google Drive tarred netCDF files (6.6 TB) EQUATES/CMAQ_12US1/INPUT/< year>/emis
CMAQ boundary condition files for 2002-2019 (monthly files of hourly 3D data at all 12US1 boundary grid cells (4)) CMAS Google Drive netCDF (8.1 TB) EQUATES/CMAQ_12US1/INPUT/< year>/icbc/BCON_CONC_12US1_CMAQv53_TS_108NHEMI_regrid_YYYYMM.nc
CMAQ initial condition files for 2002-2019 are based on EQUATES restart files for the 1st and 15th day of each month. If using these restart files for a new modeling application, users are strongly encouraged to use a 2-4 week spin-up period. CMAS Google Drive netCDF(885 GB) EQUATES/CMAQ_12US1/INPUT/< year>/icbc/CCTM__v532_cb6r3_ae7_aq_WR413_ MYR_STAGE_YYYY_12US1_YYYYMMDD.nc
CMAQ-ready meteorology inputs for 2002-2019 CMAS AWS S3 Bucket tarred netCDF files (16.8 TB) CMAQ_12US1/INPUT/2002-2019/met/mcip_v51_wrf_v411_noltng/< month>
CMAQ-ready emissions inputs for 2017 CMAS AWS S3 Bucket tarred netCDF files (6.6 TB) CMAQ_12US1/INPUT/2017/emis
CMAQ boundary condition files for 2017 (monthly files of hourly data at all 12US1 boundary grid cells) CMAS AWS S3 Bucket netCDF (8.1 TB) CMAQ_12US1/INPUT/2017/icbc/ BCON_CONC_12US1_CMAQv53_TS_108NHEMI_regrid_< year>< month>.nc
CMAQ initial condition files for 2017 are based on EQUATES restart files for the 1st and 15th day of each month. If using these restart files for a new modeling application, users are strongly encouraged to use a 2-4 week spin-up period. CMAS AWS S3 Bucket netCDF (885 GB) CMAQ_12US1/INPUT/2017/icbc/CCTM_(5)_v532_cb6r3_ae7_aq_WR413_MYR_STAGE__12US1_(6) .nc
Footnotes:
(2) Only 7 years of MCIP data are being shared due to storage space limitations/cost on the Google Drive.
(3) Two-digit month
(4) https://www.cmascenter.org/ioapi/documentation/all_versions/html/BDY.jpg
(5) Initial condition (restart) file type: CGRID, MEDIA_CONC, SOILOUT
(6) Two-digit day

EQUATES Anthropogenic Emissions Summary Files for CONUS (12US1 domain)

Purpose: For users who want to investigate spatial and temporal trends in the EQUATES anthropogenic emissions inputs.
Location of Data: These datasets are available from the CMAS Center Dataverse Repository for EQUATES (i.e., they are not saved on the CMAS Google Drive)https://doi.org/10.15139/S3/F2KJSK
Location of Meta Data: The Dataverse repository entry for EQUATES includes a meta data file, README_EQUATES_v1.0_emissions_summaries.txt
Units: All emissions data are in US tons.


Figure 3: EQUATES 12US1 modeling domain is shown as the bold rectangle. The grey shading indicates grid cells that are considered in the CONUS, including federal waters, when calculating the emissions totals in the summary files below.
EQUATES 12US1 modeling domain

Table 3

Data description File type (File size) Files are attached to the EQUATES Dataverse repository (https://doi.org/10.15139/S3/F2KJSK)
Annual total emissions for CONUS (not including offshore sources) for NOX, SO2, CO, PM2.5, PM10, VOC_regulatory (7) , NH3_nofert (8) , NH3_fert (9) 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 = NOX, SO2, CO, PM2.5, POC, PEC, VOC_regulatory, NMOG, NH3 (10) Zipped ASCII files (17MB per file) EQUATESv1.0__12US1_annual_emis sions_2002-2017.csv.gz
Monthly total gridded emissions for the 12US1 domain for 2002-2017 based on the MR emissions files for = NOX, SO2, CO, PM2.5, OC, EC, VOC_regulatory, NMOG, NH3 Zipped ASCII files (190MB per file) EQUATESv1.0__12US1_monthly_emissions_2002-2017.csv.gz
Footnotes
(7) Regulatory volatile organic compounds defined as in the Code of Federal Regulations, 40 CFR 51.100
(8) Anthropogenic NH3 emissions excluding emissions from fertilizer which were calculated online in CMAQ
(9) NH3 fertilizer emissions from agriculture, calculated online in CMAQ and post-processed to be included in these summary files
(10) Total anthropogenic NH3 emissions including emissions from fertilizer

EQUATES Surface Layer Model Output for CONUS (12US1 domain)

Purpose: For users who want to use WRF meteorology and/or 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). CMAQ 3D and vertical column air quality data can be used to evaluate the modeling system, create model-observed ¿fused¿ surfaces, and to analyze spatial and temporal changes in air quality in the upper atmosphere, e.g., https://doi.org/10.1016/j.envint.2019.104909; https://doi.org/10.5194/acp-17-12449-2017; https://doi.org/10.1029/2006JD008085; https://doi.org/10.5194/acp-15-9997-2015.
Data are available on the CMAS Google Drive and the EPA AWS Open Data Storage, as indicated in the table.
Meta Data (including units): See Tables 6-11. See also meta data on AWS. CMAQ Source Code: The EQUATES 12US1 air quality modeling is based on CMAQv5.3.2.1 (CMAQv5.3.2 with some bugfixes later released in v5.3.3). The build directory for the 12US1 CMAQ simulations is available from the EQUATES Dataverse DOI: https://doi.org/10.15139/S3/F2KJSK

EQUATES Model Output for CONUS (12US1 domain)

Purpose: For users who want to use WRF meteorology and/or 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). CMAQ 3D and vertical column air quality data can be used to evaluate the modeling system, create model-observed fused surfaces, and to analyze spatial and temporal changes in air quality in the upper atmosphere, e.g., https://doi.org/10.1016/j.envint.2019.104909; https://doi.org/10.5194/acp-17-12449-2017 ; https://doi.org/10.1029/2006JD008085; https://doi.org/10.5194/acp-15-9997-2015.
Meta Data (including units): See Tables 6-11. See also meta data on AWS.
CMAQ Source Code: The EQUATES 12US1 air quality modeling is based on CMAQv5.3.2.1 (CMAQv5.3.2 with some
bugfixes later released in v5.3.3). The build directory for the 12US1 CMAQ simulations is available from the EQUATES Dataverse DOI: https://doi.org/10.15139/S3/F2KJSK

Table 4a

Data description Data location File type (File size for all years) Location on CMAS Data Warehouse (File paths relative to this top level folder
matched WRF output with meteorological surface observations for 4 variables (Table 6) 2002-2019 CMAS Google Drive ASCII (5.3 GB) EQUATES/WRF_12US1/PAIRED_MODEL_OBS/< year>
CMAQ daily average surface concentrations for 14 species (Table 7) for 2002-2019 CMAS Google Drive netCDF (48.6 GB) and ASCII (102.9 GB) EQUATES/CMAQ_12US1/output/daily_average_surface_output/< year>
CMAQ annual total deposition for 22 species (Table 8) for 2002-2019 CMAS Google Drive GeoTIFF (244.8 MB) EQUATES/CMAQ_12US1/output/annual _total_deposition/< year>
Precipitation and bias-adjusted CMAQ annual wet and total deposition for 15 species (Table 9) for 2002-2019 CMAS Google Drive GeoTIFF (66.6 MB) EQUATES/CMAQ_12US1/output/annual_total_adjusted_wet_deposition/< year>
CMAQ hourly 3D concentrations for 35 layers and 27 species (Table 10) for 2019 EPA AWS S3 Bucket netCDF (4.3 TB) CMAQ_12US1/OUTPUT/CONC3D/COMBINE_CONC3D_v532_cb6r3_ae7_aq_WR413_MYR_STAGE_2019_12US1_2019.nc
CMAQ hourly column totals 7 species (Table 11) for 2019 EPA AWS S3 Bucket netCDF (32.4 GB) CMAQ_12US1/OUTPUT/COLUMN/COMBINE_COLUMN_v532_cb6r3_ae7_aq_WR413_MYR_STAGE_2019_12US1_2019.nc
matched CMAQ output with surface air quality observations for multiple variables (Table 13) for 2002-2019 CMAS AWS S3 Bucket ASCII (188.9 GB) EQUATES/aq_obs/// _CMAQv532_12US1_.csv

EQUATES 3D Model Output for CONUS (12US1 domain)

Purpose: For users who want to use access 3D hourly CMAQ output. Data are available on EPA¿s Remote Sensing Information Gateway (RSIG). The RSIG3D interface can be used to subset EQUATES data to a smaller spatial bounding box and select hours/days of interest and save the data in various formats. Meta Data (including units): Metadata are provided within the RSID3D interface. CMAQ Source Code: The EQUATES 12US1 air quality modeling is based on CMAQv5.3.2.1 (CMAQv5.3.2 with some bugfixes later released in v5.3.3). The build directory for the 12US1 CMAQ simulations is available from the EQUATES Dataverse DOI: https://doi.org/10.15139/S3/F2KJSK

Table 4b

Data description Data location File type (File size for all years) Location on CMAS Data Warehouse (File paths relative to this top level folder
CMAQ hourly 3D concentrations for 44 layers for all model output species for 2002-2019 EPA RSIG EQUATES data can be saved in various formats Directions for accessing EQUATES data on RSIG

EQUATES Model Output for Northern Hemisphere (108NHemi domain)

Purpose: Daily average 3D data for all species is suitable for users who want to examine continental-scale air quality trends or who want to create boundary conditions for any subset domain in the Northern Hemisphere. Hourly CMAQ 3D and vertical column air quality data for a subset of species can be used to evaluate the modeling system, create model-observed fused surfaces, and to analyze spatial and temporal changes in air quality in the upper atmosphere, e.g., https://doi.org/10.1016/j.envint.2019.104909; https://doi.org/10.5194/acp-17-12449-2017; https://doi.org/10.1029/2006JD008085; https://doi.org/10.5194/acp-15-9997-2015. Data are available on the CMAS Google Drive and the CMAS AWS Open Data Storage, as indicated in the table.
Location of Meta Data: See the CMAQ IC/BC Tutorial on GitHub:
https://github.com/USEPA/CMAQ/blob/main/DOCS/Users_Guide/Tutorials/CMAQ_UG_tutorial_HCMAQ_IC_BC.md
Units: Units for each variable are included in the CMAQ netCDF files.
CMAQ Source Code: The EQUATES 108NHEMI air quality modeling is based on H-CMAQv5.3.2.1 (v5.3.2 with some bugfixes later released in v5.3.3 and modifications to halogen chemistry and O3-PV scaling). The build directory for the H-CMAQ simulations is available from the EQUATES Dataverse DOI: https://doi.org/10.15139/S3/F2KJSK

Table 5

Data description Data location File type (File size for all years) Location on CMAS Data Warehouse (File paths relative to this top level folder
CMAQ daily average 3D output for 44 layers for 260 model variables for 2002-2019 (11) CMAS Google Drive netCDF (10.8 TB) CMAQ_108NHemi/OUTPUT//CTM_CONC_v532_intel18.0_CMAQv53_TS_108NHEMI__dailyav.nc
CMAQ daily average 3D output for 44 layers for 260 model variables for 2018-2019 ^12 CMAS AWS S3 Bucket netCDF (1.2 TB) CMAQ_108NHemi// CTM_CONC_v532_intel18.0_CMAQv53_TS_108NHEMI__dailyav.nc
CMAQ hourly 3D concentrations for 44 layers and 22 species (Table 12) for 2019 EPA AWS S3 Bucket netCDF (1.1 TB) CMAQ_108NHEMI/OUTPUT/CONC3D/COMBINE_CONC3D_v532_intel18.0_CMAQv53_TS_108NHEMI_2019.nc
CMAQ hourly column totals 7 species (Table 11) for 2019 EPA AWS S3 Bucket netCDF (8.3 GB) CMAQ_108NHEMI /OUTPUT/COLUMN/COMBINE_COLUMN_v532_intel18.0_CMAQv53_TS_108NHEMI_2019.nc
Footnotes
(11) can be used to created CMAQ BCs

List of Column Names and Descriptions in 12US1 Paired Model/Obs Files


Table 6: Hourly surface meteorological values for 12US1 from the Weather Research & Forecasting (WRF) model matched in space and time to observations from the Meteorological Assimilation and
Data Ingest System of the National Oceanic and Atmospheric Administration.
Column name in .csv file Variable description Units
Date Time Date and time stamp in UTC
SiteID Weather station ID
Temp Mod (K) Modeled 2-meter temperature (WRF estimate) K
Temp Obs (K) Observed 2-meter temperature K
Q Mod (g/kg) Modeled 2-meter water vapor mixing ratio (WRF estimate) g/kg
Q Obs (g/kg) Observed 2-meter water vapor mixing ratio g/kg
WS Mod (m/s) Modeled 10-meter wind speed (WRF estimate) m/s
WS Obs (m/s) Observed 10-meter wind speed m/s
WD Mod (Deg) Modeled 10-meter wind direction (WRF estimate) degrees
WD Obs (Deg) Observed 10-meter wind direction degrees

List of Available Species in 12US1 Concentration and Deposition Files


Table 7: Daily average surface concentrations for 12US1. The species definition file (SpecDef_cb6r3_ae6_aq.txt) can be found here: https://github.com/USEPA/CMAQ/blob/5.3.2/CCTM/src/MECHS/cb6r3_ae6_aq/SpecDef_cb6r3_ae6_aq.txt
Variable name in .csv Model species defined in SpecDef_cb6r3_ae6_aq.txt Variable description (daily average unless otherwise noted) Units
column CMAQ 12US1 grid column number
row CMAQ 12US1 grid row number
longitude Longitude of grid cell center degrees
latitude Latitude of grid cell center degrees
Lambert_X Projected x coordinate of grid cell center meters
LAMBERT_Y Projected y coordinate of grid cell center meters
date Date formatted as YYYY-MM-DD
CO_AVG CO Carbon Monoxide ppb
NO_AVG NO Nitric Oxide ppb
NO2_AVG NO2 Nitrogen Dioxide ppb
CH2O_AVG FORM Formaldehyde ppb
O3_AVG O3 Ozone ppb
O3_MDA8 O3 Daily Maximum 8-hr Average Ozone ppb
SO2_AVG SO2 Sulfur Dioxide ppb
PM2.5_AVG PM25_TOT Total PM2.5 (sharp cutoff computed using modeled size distribution) ug/m3
PM10_AVG PM10 Particulate Matter up to 10 micrometers in µg/m3 Diameter ug/m3
PM25_NO3_AVG PM25_NO3 PM2.5 Nitrate (sharp cutoff computed using modeled size distribution) ug/m3
PM25_NH4_AVG PM25_NH4 PM2.5 Ammonium (sharp cutoff computed using modeled size distribution) ug/m3
PM25_SO4_AVG PM25_SO4 PM2.5 Sulfate (sharp cutoff computed using modeled size distribution) ug/m3
PM25_OC_AVG PM25_OC PM2.5 Organic Carbon (sharp cutoff computed using modeled size distribution) ug/m3
PM25_EC_AVG PM25_EC PM2.5 Elemental Carbon (sharp cutoff computed using modeled size distribution) ug/m3




Table 8: Annual total deposition for 12US1. The species definition file (SpecDef_Dep_cb6r3_ae6_aq.txt) can be found here: https://github.com/USEPA/CMAQ/blob/5.3.2/CCTM/src/MECHS/cb6r3_ae6_aq/SpecDef_Dep_cb6r3_ae6_aq.txt

Variable name for GeoTIFF file Model species defined in SpecDef_Dep_cb6r3_ae6_aq.txt Variable description Units
WETDEP_TNO3_12US1 WDEP_TNO3 Wet Deposition of Total Nitrate (includes HNO3, NO3) kg/ha
WETDEP_NHX_12US1 WDEP_NHX Wet Deposition of NHX (includes NH4, NH3) kg/ha
WETDEP_TSO4_12US1 WDEP_TSO4 Wet Deposition of Total Sulfate (includes SO4>, SO2) kg/ha
WETDEP_OXN_12US1 WD_OXN_TOT Wet Deposition of Oxidized Nitrogen (includes NOX, TNO3, PANs, Organic Nitrates, N2O5, HONO, PNA) kg-N/ha
WETDEP_REDN_12US1 WD_REDN_TOT Wet Deposition of Reduced Nitrogen (includes NH4, NH3) kg-N/ha
WETDEP_N_12US1 WETDEP_OXN + WETDEP_REDN Wet Deposition of Nitrogen kg-N/ha
WETDEP_S_12US1 WD_S_TOT Wet Deposition of Sulfur kg-S/ha
WETDEP_CL_12US1 WDEP_TCL Wet Deposition of Chloride kg/ha
WETDEP_NA_12US1 WDEP_ANAJK Wet Deposition of Sodium kg/ha
DRYDEP_OXN_12US1 DD_OXN_TOT Dry Deposition of Oxidized Nitrogen (includes NOX, TNO3, PANs, Org N, N2O5, HONO, PNA) kg-N/ha
DRYDEP_REDN_12US1 DD_REDN_T Dry Deposition of Reduced Nitrogen (includes NH4, NH3) kg-N/ha
DRYDEP_N_12US1 DD_OXN_TOT + DD_REDN_T Dry Deposition of Nitrogen kg-N/ha
DRYDEP_S_12US1 DD_S_TOT Dry Deposition of Sulfur kg-S/ha
DRYDEP_CL_12US1 DDEP_ACLJK Dry Deposition of Chloride kg/ha
DRYDEP_NA_12US1 DDEP_ANAJK Dry Deposition of Sodium kg/ha
TOTDEP_OXN_12US1 DD_OXN_TOT + WETDEP_OXN Total (Dry + Wet) Deposition of Oxidized Nitrogen kg-N/ha
TOTDEP_REDN_12US1 DD_REDN_T + WETDEP_REDN Total (Dry + Wet) Deposition of Reduced Nitrogen kg-N/ha
TOTDEP_N_12US1 TOTDEP_OXN + TOTDEP_REDN Total (Dry + Wet) Deposition of Nitrogen kg-N/ha
TOTDEP_S_12US1 DRYDEP_S + WETDEP_S Total (Dry + Wet) Deposition of Sulfur kg-S/ha
TOTDEP_CL_12US1 DDEP_CL + WETDEP_CL Total (Dry + Wet) Deposition of Chloride kg/ha
TOTDEP_NA_12US1 DDEP_NA + WETDEP_NA Total (Dry + Wet) Deposition of Sodium kg/ha
WRF_PRECIP_12US1 RT WRF Precipitation cm



Table 9: Annual total deposition for 12US1 using precipitation and bias-adjusted wet deposition estimates. CMAQ deposition outputs are adjusted using PRISM precipitation data and NADP/NTN wet deposition measurements following the method in Benish et al. (2022) Since the PRISM and NTN data are only available for the US, model values in grid cells outside of the Conterminous US (CONUS) are set to missing.


Variable name for GeoTIFF Model species defined in SpecDef_Dep_cb6r3_ae6_aq.txt Variable description Units
ADJ_WETDEP_TNO3_CONUS precip_NO3_bias_factor*WDEP_TNO3 Precipitation and Bias Adjusted Wet Deposition of Total Nitrate (includes HNO3, NO3) kg/ha
ADJ_WETDEP_NHX_CONUS precip_NH4_bias_factor*WDEP_NHX Precipitation and Bias Adjusted Wet Deposition of NHX (includes NH4, NH3) kg/ha
ADJ_WETDEP_TSO4_CONUS precip_SO4_bias_factor*WDEP_TSO4 Precipitation and Bias Adjusted Wet Deposition of Total Sulfate includes SO4, SO2 kg/ha
ADJ_WETDEP_CL_CONUS precip_factor*WDEP_TCL Precipitation Adjusted Wet Deposition of Chloride kg/ha
ADJ_WETDEP_NA_CONUS precip_factor*WDEP_ANAJK Precipitation Adjusted Wet Deposition of Sodium kg/ha
ADJ_WETDEP_OXN_CONUS precip_NO3_bias_factor*WD_OXN_TOT Precipitation and Bias Adjusted Wet Deposition of Oxidized Nitrogen (includes NOX, TNO3, PANs, Organic Nitrates, N205, HONO, PNA) kg-N/ha
ADJ_WETDEP_REDN_CONUS precip_NH4_bias_factor*WD_REDN_T Precipitation and Bias Adjusted Wet Deposition of Reduced Nitrogen (includes NH4, NH3) kg-N/ha
ADJ_WETDEP_N_CONUS ADJ_WETDEP_OXN + Precipitation and Bias Adjusted Wet Deposition of Nitrogen kg-N/ha
ADJ_WETDEP_S_CONUS precip_SO4_bias_factor*WD_S_TOT Precipitation and Bias Adjusted Wet Deposition of Sulfur kg-S/ha
ADJ_TOTDEP_OXN_CONUS DD_OXN_TOT + ADJ_WETDEP_OXN Total (Dry + Precip/Bias Adjusted Wet) Deposition of Oxidized Nitrogen kg-N/ha
ADJ_TOTDEP_REDN_CONUS DD_REDN_T + ADJ_WETDEP_REDN Total (Dry + Precip/Bias Adjusted Wet) Deposition of Reduced Nitrogen kg-N/ha
ADJ_TOTDEP_N_CONUS TOTDEP_OXN + TOTDEP_REDN Total (Dry + Precip/Bias Adjusted Wet) Deposition of Nitrogen kg-N/ha
ADJ_TOTDEP_S_CONUS DRYDEP_S + ADJ_WETDEP_S Total (Dry + Precip/Bias Adjusted Wet) Deposition of Sulfur kg-S/ha
ADJ_TOTDEP_CL_CONUS DDEP_CL + ADJ_WETDEP_CL Total (Dry + Precip Adjusted Wet) Deposition of Chloride kg/ha
ADJ_TOTDEP_NA_CONUS DDEP_NA + ADJ_WETDEP_NA Total (Dry + Precip Adjusted Wet) Deposition of Sodium kg/ha



Table 10: Hourly 3D concentrations for 27 model variables for 12US1 domain.
Variable name in .ncf file Variable description Units
AIR_DENS Air Density kg/m3
PRESS Pressure Pa
TEMP Temperature K
QV Water vapor mixing ratio kg/kg
ZH Mid-layer height above ground m
ZF Full-layer height above ground m
CO Carbon Monoxide ppbv
FORM Formaldehyde ppbv
NH3 Ammonia ppbv
NO Nitrogen Oxide ppbv
NO2 Nitrogen Dioxide ppbv
O3 Ozone ppbv
SO2 Sulfur Dioxide ppbv
ISOP Isoprene ppbv
GLY Glyoxal ppbv
ANO3_PPB Aerosol Nitrate in ppb by volume ppbv
NTR Organic Nitrates ppbv
PANS Peroxyacylnitrate ppbv
NOY All oxides of nitrogen in which the oxidation state of the N atom is +2 or greater, i.e., the sum of all reactive nitrogen oxides including NOX (NO + NO2) and other nitrogen oxides referred to as NOZ. ppbv
ASOILJ Soil (accumulation mode ) = 2.20*AL+2.49*SI+1.63*CA+2.42*FE+1.94*TI ug/m3
AECIJ PM2.5 Elemental Carbon (Aitken and accumulation modes) ug/m3
ANO3IJ PM2.5 nitrate (Aitken and accumulation modes) ug/m3
ANH4IJ PM2.5 ammonium (Aitken and accumulation modes) ug/m3
ASO4IJ PM2.5 sulfate (Aitken and accumulation modes) ug/m3
AOCIJ PM2.5 Organic Carbon (Aitken and accumulation modes) ug/m3
AOMIJ PM2.5 Organic Matter (Aitken and accumulation modes) ug/m3
ATOTIJ Total PM2.5 Mass (Aitken and accumulation modes) ug/m3



Table 11: Column totals for 7 model variables for 12US1 or 108NHemi domains.
Variable name in .ncf file Variable description Units
NO2_COLUMN Nitrogen Dioxide petamolec/cm2
CO_COLUMN Carbon Monoxide petamolec/cm2
SO2_COLUMN Sulfur Dioxide petamolec/cm2
HCHO_COLUMN Formaldehyde petamolec/cm2
O3_COLUMN Ozone Column Total DU
JNO2_COLUMN NO2 Photolysis Rate Coefficient min-1
AOD550 Aerosol Optical Depth at a Wavelength of 550 nm
Footnotes
(12) https://www.epa.gov/system/files/documents/2022-08/PM_2021.pdf


Table 12: Hourly 3D concentrations for 22 model variables for 108NHEMI domain
Variable name in .ncf file Variable description Units
AIR_DENS Air Density kg/m3
PRESS Pressure Pa
TEMP Temperature K
QV Water vapor mixing ratio kg/kg
ZH Mid-layer height above ground m
ZF Full-layer height above ground m
PV Potential Vorticity m2 s-1K kg-1
CO Carbon Monoxide ppbv
FORM Formaldehyde ppbv
NH3 Ammonia ppbv
NO2 Nitrogen Dioxide ppbv
O3 Ozone ppbv
O3PV Ozone Potential Vorticity (15) ppbv
SO2 Sulfur Dioxide ppbv
ASOILJ Soil (accumulation mode ) = 2.20*AL+2.49*SI+1.63*CA+2.42*FE+1.94*TI ug/m3
AECIJ PM2.5 Elemental Carbon (Aitken and accumulation modes) ug/m3
ANO3IJ PM2.5 nitrate (Aitken and accumulation modes) ug/m3
ANH4IJ PM2.5 ammonium (Aitken and accumulation modes) ug/m3
ASO4IJ PM2.5 sulfate (Aitken and accumulation modes) ug/m3
AOCIJ PM2.5 Organic Carbon (Aitken and accumulation modes) ug/m3
AOMIJ PM2.5 Organic Matter (Aitken and accumulation modes) ug/m3
ATOTIJ Total PM2.5 Mass (Aitken and accumulation modes) ug/m3

List of Column Names and Descriptions in 12US1 Paired Model/Obs Evaluation Files

Surface air quality and deposition estimates (hourly/daily/weekly) for 12US1 from CMAQv5.3.2 paired in space and time to measurement data for 01/01/2002 - 12/31/2019. The paired model and observation data are saved as monthly files for seven different network/metric combinations.
Table 13a: Files names, approximate size per file, and brief description.
File name (Abbreviated file name) Size Description
AQS_Daily_CMAQv532_12US1_{YEAR}.csv (AQS_Daily) ~30-50 MB daily average PM2.5 and constituents from EPA¿s AQS (including data from CSN and IMPROVE networks )
AQS_Daily_O3_CMAQv532_12US1_{YEAR}.csv (AQS_Daily_O3) ~3-5 MB MDA8 O3 and other daily ozone metrics from EPA¿s AQS (including data from CASTNET)
AQS_Hourly_CMAQv532_12US1_{YEAR}.csv (AQS_Hourly) ~500-900 MB hourly PM2.5, ozone, NOX, other gaseous pollutants, and meteorological variables from EPA¿s AQS (including data from CASTNET)
CASTNET_Daily_CMAQv532_12US1_{YEAR}.csv (CASTNET_Daily) ~400-500 KB MDA8 O3 and other daily ozone metrics from CASTNET
NADP_CMAQv532_12US1_{YEAR}.csv (NADP) ~450-550 KB weekly total precipitation, wet deposition, and wet concentration from NADP/NTN
NAPS_CMAQv532_12US1_{YEAR}.csv (NAPS) ~40-50 MB hourly PM2.5, ozone, NOX, other gaseous pollutant from NAPS (Canadian sites)
NAPS_Daily_CMAQv532_12US1_{YEAR}.csv (NAPS_Daily) ~ 1 MB or less MDA8 O3 and other daily ozone metrics from NAPS (Canadian sites)

Table 13b: This table provides a list of variables across all of the files, what files include the variable, a brief description, and units. Each of the .csv files includes 17 or 21 columns with information on spatial location and timestamp (in local time) of the model and observed data. The remaining columns are the paired observational data (columns ending with '_ob') and model estimates (columns ending with '_mod'). The '_mod' and '_ob' have been removed from the variable names in this table for simplicity. Note that the AQS_Hourly files have several '_mod' columns and no corresponding '_ob' columns. These are to provide modeled meteorological variables to inform model evaluation.
The species definition of the model variables are available in the CMAQ GitHub repository: SpecDef_Def_cb6r3_ae7_aq.txt. The Measurement Sampling Method codes for the observational data are defined on the EPA¿s AQS site: https://aqs.epa.gov/aqsweb/documents/codetables/methods_all.html Important information on how model species are paired with observed data is available in the AMET_Release_Observation_Files_Readme.txt available on the CMAS AWS S3 bucket for AMET. The mapping of measurement data to observations is available in the AMET GitHub repository: AQ_species_list.input.
There are multiple versions of modeled PM2.5 and component species included in the AQS_Daily and AQS_Hourly files for transparency and research purposes. For model evaluation we recommend using: PM25_TOT, PM25_SO4, PM25_NO3, PM25_NH4, PM25_OC, PM25_EC, PM25_TC.
The 'PM25_*_mod' columns for these variables are the model estimates based on a sharp cutoff of 2.5 micrometers computed using the modeled size distribution.
'PM25_*_ob' columns for these variables use the best available sampling method at the time. This is described further in the AMET_Release_Observation_Files_Readme.txt.

' td>kg/ha
Variable Name Files Containing Variable Description Units
SiteId All 9 digit site identifier for AQS_Hourly, AQS_Daily, AQS_Daily_O3: https://www.epa.gov/aqs/site-id-format CASNET site ids: https://www.epa.gov/castnet/castnet-site-locations NADP NTN site ids: https://nadp.slh.wisc.edu/ntn-site-list/
POCode All Numerical Parameter Occurrence Code used to distinguish between multiple instruments measuring the same pollutant at the same measurement site for AQS_Hourly, AQS_Daily, AQS_Daily_O3. For all other networks, POCode is set to 1 for all sites.
State All State name (Province name for NAPS sites)
County All County name (N/A for NAPS sites)
Elevation All Elevation of measurement site Meters
Latitude All Latitude of measurement site decimal degrees
Longitude All Longitude of measurement site decimal degrees
Column All Number between 1 and 459 indicating the column number (moving West to East) of CMAQ grid cell containing the measurement site (based on the CMAQ 12US1 modeling domain which is a uniform 12km x 12km grid in Lambert conformal projected space)
Row All Number between 1 and 299 indicating the row number (moving South to North) of CMAQ grid cell containing the measurement site (based on the CMAQ 12US1 modeling domain which is a uniform 12km x 12km grid in Lambert conformal projected space)
Time On All Character sting with format MM/DD/YYYY HH:MM indicating the start time of the measurement in Local Standard Time (LST)
Time Off All Character sting with format MM/DD/YYYY HH:MM indicating the end time of the measurement in LST
SMM All Two digit starting month of the measurement, e.g., 01 for January
SDD All Two digit starting day of the measurement, e.g., 01 for the first day of the month
SYYYY All Four digit starting year of the measurement, e.g., 2002
Shh AQS_DAILY, AQS_Hourly, NADP, NAPS Two digit starting hour of the measurement, e.g. 08 for 8am local time
Smm AQS_DAILY, AQS_Hourly, NADP, NAPS Two digit starting minute of the measurement, e.g. 15 for 15 minutes past the hour
EMM All Two digit ending month of the measurement
EDD All Two digit ending day of the measurement
EYYYY All Four digit ending year of the measurement
Ehh AQS_DAILY, AQS_Hourly, NADP, NAPS Two digit ending hour of the measurement
Emm AQS_DAILY, AQS_Hourly, NADP, NAPS Two digit ending minute of the measurement
PM25_TOT AQS_DAILY, AQS_Hourly, NAPS Total PM2.5 mass (sharp cutoff for model values computed using modeled size distribution) µg/m3
PM25_SO4 AQS_DAILY PM2.5 Sulfate (sharp cutoff for model values computed using modeled size distribution) µg/m3
PM25_NO3 AQS_DAILY PM2.5 Nitrate (sharp cutoff for model values computed using modeled size distribution) µg/m3
PM25_NH4 AQS_DAILY PM2.5 Ammonium (sharp cutoff for model values computed using modeled size distribution) µg/m3
PM25_OC AQS_DAILY PM2.5 Organic Carbon (sharp cutoff for model values computed using modeled size distribution) µg/m3
PM25_EC AQS_DAILY PM2.5 Elemental Carbon (sharp cutoff for model values computed using modeled size distribution) µg/m3
PM25_TC AQS_DAILY PM2.5 Total Carbon (sharp cutoff for model values computed using modeled size distribution) µg/m3
PM10 AQS_DAILY, AQS_Hourly, NAPS Total PM10 mass (sharp cutoff for model values computed using modeled size distribution) µg/m3
Acetaldehyde AQS_DAILY Acetaldehyde (VOC) ppb
Formaldehyde AQS_DAILY Formaldehyde (VOC) ppb
Benzene AQS_DAILY Benzene (VOC) ppb
Isoprene AQS_DAILY, AQS_Hourly Isoprene (VOC) ppb
Ethylene AQS_DAILY, AQS_Hourly Ethylene (VOC) ppb
Ethane AQS_DAILY, AQS_Hourly Ethane (VOC) ppb
Toluene AQS_DAILY, AQS_Hourly Toluene (VOC) ppb
Na AQS_DAILY Sodium µg/m3
Cl AQS_DAILY Chloride µg/m3
NaCl AQS_DAILY Sodium Chloride µg/m3
Fe AQS_DAILY Iron µg/m3
Al AQS_DAILY Aluminum µg/m3
Si AQS_DAILY Silicon µg/m3
Ti AQS_DAILY Titanium µg/m3
Ca AQS_DAILY Calcium µg/m3
MgAQS_DAILY Magnesium >µg/m3
K AQS_DAILY Potassium >µg/m3
Mn AQS_DAILY Maganese >µg/m3
PM25_OC_88305 AQS_DAILY PM2.5 organic carbon (sharp cutoff for model values computed using modeled size distribution; measurement sampling method 88305) µg/m3
PM25_EC_88307 AQS_DAILY PM2.5 elemental carbon (sharp cutoff for model values computed using modeled size distribution; measurement sampling method 88307) µg/m3
PM25_TC_88305 AQS_DAILY PM2.5 total carbon (sharp cutoff for model values computed using modeled size distribution; measurement sampling method 88305) µg/m3
PM25_OC_88370 AQS_DAILY PM2.5 organic carbon (sharp cutoff for model values computed using modeled size distribution; measurement sampling method 88370) µg/m3
PM25_EC_88380 AQS_DAILY PM2.5 elemental carbon (sharp cutoff for model values computed using modeled size distribution; measurement sampling method 88380) µg/m3
PM25_TC_88370 AQS_DAILY PM2.5 total carbon (sharp cutoff for model values computed using modeled size distribution; measurement sampling method 88370) µg/m3
PM25_OC_88320 AQS_DAILY PM2.5 organic carbon (sharp cutoff for model values computed using modeled size distribution; measurement sampling method 88320) µg/m3
PM25_EC_88320 AQS_DAILY PM2.5 elemental carbon (sharp cutoff for model values computed using modeled size distribution; measurement sampling method 88320) µg/m3
PM25_TC_88320 AQS_DAILY PM2.5 total carbon (sharp cutoff for model values computed using modeled size distribution; measurement sampling method 88320) µg/m3
PM_TOT_88101 AQS_DAILY Total PM2.5 (modeled values represent Aitken and accumulation modes; measurement sampling method 88101) µg/m3
PM_TOT_88502 AQS_DAILY Total PM2.5 (modeled values represent Aitken and accumulation modes; measurement sampling method 88502) µg/m3
PM_TOT AQS_DAILY, AQS_Hourly, NAPS Total PM2.5 mass (modeled values represent Aitken and accumulation modes) µg/m3
SO4 AQS_DAILY PM2.5 Sulfate (modeled values represent Aitken and accumulation modes) µg/m3
NO3 AQS_DAILY PM2.5 Nitrate (modeled values represent Aitken and accumulation modes) µg/m3
NH4 AQS_DAILY PM2.5 Ammonium (modeled values represent Aitken and accumulation modes) µg/m3
OC AQS_DAILY PM2.5 Organic Carbon (modeled values represent Aitken and accumulation modes) µg/m3
EC AQS_DAILY PM2.5 Elemental Carbon (modeled values represent Aitken and accumulation modes) µg/m3
TC AQS_DAILY PM2.5 Total Carbon (modeled values represent Aitken and accumulation modes) µg/m3
OC_88305 AQS_DAILY Organic carbon (modeled Aitken and accumulation modes; measurement sampling method 88305) µg/m3
EC_88307 AQS_DAILY Elemental carbon (modeled Aitken and accumulation modes; measurement sampling method 88307) µg/m3
TC_88305 AQS_DAILY Total carbon (modeled Aitken and accumulation modes; measurement sampling method 88305) µg/m3
OC_88370 AQS_DAILY Organic carbon (modeled Aitken and accumulation modes; measurement sampling method 88370) µg/m3
EC_88380 AQS_DAILY Elemental carbon (modeled Aitken and accumulation modes; measurement sampling method 88380) µg/m3
TC_88370 AQS_DAILY Total carbon (modeled Aitken and accumulation modes; measurement sampling method 88370) µg/m3
OC_88320 AQS_DAILY Organic carbon (modeled Aitken and accumulation modes; measurement sampling method 88320) µg/m3
EC_88320 AQS_DAILY Elemental carbon (modeled Aitken and accumulation modes; measurement sampling method 88320) µg/m3
TC_88320 AQS_DAILY Total carbon (modeled Aitken and accumulation modes; measurement sampling method 88320) µg/m3
PM10_IJK AQS_DAILY PM10 (modeled values represent Aitken, accumulation and coarse modes) µg/m3
soil AQS_DAILY Soil (accumulation mode) = 2.20*AL+2.49*SI+1.63*CA+2.42*FE+1.94*TI >µg/m3
OTHER AQS_DAILY Difference between PM2.5 total and PM component species: PM25_TOT-(PM25_CL+PM25_EC+PM25_NA+PM25_NH4+ PM25_NO3+PM25_OC+PM25_SOIL+PM25_SO4) (see species definition in AQ_species_list.input) µg/m3
NCOM AQS_DAILY Non-combustion organic matter see species definition in AQ_species_list.input µg/m3
OTHER_REM AQS_DAILY PM Other without NCOM: OTHER - NCOM (see species definition in AQ_species_list.input µg/m3
PM_FRM AQS_DAILY, AQS_Hourly PM2.5 measured by Federal Reference Method (modeled values represent Aitken, accumulation and coarse modes; see species definition in SpecDef_cb6r3_ae7_aq.txt) µg/m3
PM25_FRM AQS_DAILY, AQS_Hourly PM2.5 measured by Federal Reference Method (sharp cutoff for model values computed using modeled size distribution; see species definition in SpecDef_cb6r3_ae7_aq.txt µg/m3
O3_1hrmax AQS_Daily_O3, CASTNET_Daily, NAPS_Daily_O3 1-hour maximum ozone concentration ppb
O3_1hrmax_9cell AQS_Daily_O3, CASTNET_Daily, NAPS_Daily_O3 1-hour max ozone, 9-cell average ppb
O3_1hrmax_time AQS_Daily_O3, CASTNET_Daily, NAPS_Daily_O3 Hour of 1-hour max ozone (e.g., 14 for 2pm LST)
O3_8hrmax AQS_Daily_O3, CASTNET_Daily, NAPS_Daily_O3 Maximum daily 8-hour average ozone ppb
O3_8hrmax_9cell AQS_Daily_O3, CASTNET_Daily, NAPS_Daily_O3 Maximum daily 8-hour average (MDA8) ozone averaged over 9 grid cells surrounding the monitoring site ppb
O3_8hrmax_time AQS_Daily_O3, CASTNET_Daily, NAPS_Daily_O3 Start hour of MDA8 ozone (e.g., 9 for 9am LST)
W126 AQS_Daily_O3, CASTNET_Daily, NAPS_Daily_O3 Ozone exposure index (W126) (See the EPAs webpage on the Ozone W126 metric) ppm-hours
SUM06 AQS_Daily_O3, CASTNET_Daily, NAPS_Daily_O3 Ozone exposure index (SUM06) (See the .pdf of EPAs 2007 Technical Report on Ozone Exposure, Risk, and Impact Assessments for Vegetation section 1) ppm-hours
SFC_TMP AQS_Hourly Surface temperature (at 10 meters for measurement data) C
RH AQS_Hourly Relative humidity (at 10 meters for measurement data) %
WSPD10 AQS_Hourly Wind speed (at 10 meters for measurement data) m/s
PBLH AQS_Hourly Planetary boundary layer height (model value only) m
Solar_Rad AQS_Hourly Solar radiation watts/m2
precip AQS_Hourly Precipitation mm/hour
NOY AQS_Hourly All oxides of nitrogen in which the oxidation state of the N atom is +2 or greater, i.e., the sum of all reactive nitrogen oxides including NOX (NO + NO2) and other nitrogen oxides referred to as NOZ. ppb
O3 AQS_Hourly, NAPS Ozone ppb
NO AQS_Hourly, NAPS Nitric oxide ppb
NO2 AQS_Hourly, NAPS Nitrogen dioxide ppb
NOX AQS_Hourly, NAPS Nitrogen oxides (NO + NO2) ppb
CO AQS_Hourly, NAPS Carbon monoxide ppb
SO2 AQS_Hourly, NAPS Sulfur dioxide ppb
Valcode NADP Validation code
Invalcode NADP Invalid code
NH4_dep NADP Ammonium wet deposition kg/ha
NO3_dep NADP Nitrate wet deposition kg/ha
SO4_dep NADP Sulfate wet deposition
Cl_dep NADP Chloride wet deposition kg/ha
Na_dep NADP Sodium wet deposition kg/ha
CA_dep NADP Calcium wet deposition kg/ha
MG_dep NADP Magnesium wet deposition kg/ha
K_dep NADP Potassium wet deposition kg/ha
NH4_conc NADP Ammonium wet concentration mg/l
NO3_conc NADP Nitrate wet concentration mg/l
SO4_conc NADP Sulfate wet concentration mg/l
Cl_conc NADP Chloride wet concentration mg/l
Na_conc NADP Sodium wet concentration mg/l
CA_conc NADP Calcium wet concentration mg/l
MG_conc NADP Magnesium wet concentration mg/l
K_conc NADP Potassium wet concentration mg/l
Precip NADP Precipitation mm

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