Model Variables
Variable names in hourly data files:
Variable Name,
Units,
Variable Description
CO, ppb, carbon monoxide
NO, ppb, nitric oxide
NO2, ppb, nitrogen dioxide
O3, ppb, ozone
SO2, ppb, sulfur dioxide
SO2_UGM3, micrograms/m^3, sulfur dioxide
AECIJ, micrograms/m^3, aerosol elemental carbon (sum of i-mode and j-mode)
*
AOCIJ, micrograms/m^3, aerosol organic carbon (sum of i-mode and j-mode)
*
ANO3IJ, micrograms/m^3, aerosol nitrate (sum of i-mode and j-mode)
*
TNO3, micrograms/m^3, total nitrate= NO3 (ANO3IJ)+ nitric acid (HNO3)
ANH4IJ,micrograms/m^3, aerosol ammonium (sum of i-mode and j-mode)
*
ASO4IJ,micrograms/m^3, aerosol sulfate (sum of i-mode and j-mode)
*
PMIJ
**, micrograms/m^3, total fine particulate matter (sum of i-mode and j-mode)
*
PM10
**, micrograms/m^3, total particulate matter (sum of i-mode, j-mode, k-mode)
*
Variable names in daily data files:
Note: All daily averages are computed using Local Standard Time (LST)
Variable Name,
Units,
Variable Description
CO_AVG, ppb, 24-hr average carbon monoxide
NO_AVG, ppb, 24-hr average nitric oxide
NO2_AVG, ppb, 24-hr average nitrogen dioxide
O3_AVG, ppb, 24-hr average ozone
O3_MDA8, ppb, Maximum daily 8-hr average ozone
+
SO2_AVG, ppb, 24-hr average sulfur dioxide
SO2_UGM3_AVG, micrograms/m^3, 24-hr average sulfur dioxide
AECIJ_AVG, micrograms/m^3, 24-hr average aerosol elemental carbon (sum of i-mode and j-mode)
*
AOCIJ_AVG, micrograms/m^3, 24-hr average aerosol organic carbon (sum of i-mode and j-mode)
*
ANO3IJ_AVG, micrograms/m^3, 24-hr average aerosol nitrate (sum of i-mode and j-mode)
*
TNO3_AVG, micrograms/m^3, 24-hr average total nitrate= NO3 (ANO3IJ)+ nitric acid (HNO3)
ANH4IJ_AVG,micrograms/m^3, 24-hr average aerosol ammonium (sum of i-mode and j-mode)
*
ASO4IJ_AVG,micrograms/m^3, 24-hr average aerosol sulfate (sum of i-mode and j-mode)
*
PMIJ_AVG
**, micrograms/m^3, 24-hr average total fine particulate matter (sum of i-mode and j-mode)
*
PM10_AVG
**, micrograms/m^3, 24-hr average total particulate matter (sum of i-mode, j-mode, k-mode)
*
+The calculation of the MDA8 O3 variable is based on the current ozone NAAQS and is derived from the highest of the 17 consecutive 8-hr averages beginning with the 8-hr period from 7:00am to 3:00pm LST and ending with the 8-hr period from 11pm to 7am the following day.
*CMAQ represents PM using three interacting lognormal distributions, or modes. Two modes, Aitken (i-mode) and accumulation (j-mode) are generally less than 2.5 microns in diameter while the coarse mode (k-mode) contains significant amounts of mass above 2.5 microns.
**Note that modeled size distributions can also be used to output PM species that represent the aerosol mass that falls below a specific diameter, e.g. 2.5 um or 10um. The output variables that are based on the sharp cut-off method are typically very similar to the aggregate PMIJ (i+j mode) and PM10 (i+j+k mode) variables included in these files. Further information on particle size-composition distributions in CMAQv5.0 can be found in Nolte et al. (2015),
https://doi.org/10.5194/gmd-8-2877-2015.