The VIIRS/NOAA20 Deep Blue Level 3 monthly aerosol data, 1x1 degree grid, Short-name AERDB_M3_VIIRS_NOAA20 product is derived from the Version-2.0 (V2.0) daily L3 gridded products (AERDB_D3_VIIRS_NOAA20), and is provided in a 1 x 1 degree horizontal resolution grid. Arithmetic mean values from the daily L3 gridded products also provide the basis to derive a complement of statistics for the monthly aggregated products. To exclude poorly sampled grid elements, the algorithm requires at least 3 valid days’ worth of data to render a given monthly grid element as valid. This monthly product record starts from January 5th, 2018. This L3 monthly product, in netCDF format, contains 45 Science Data Set (SDS) layers that are named identical to the SDSs in the daily L3 product.

For more information about the product and Science Data Set (SDS) layers, consult product page at:
https://ladsweb.modaps.eosdis.nasa.gov/missions-and-measurements/products/AERDB_M3_VIIRS_NOAA20

Or

Consult Deep Blue aerosol team Page at:
https://deepblue.gsfc.nasa.gov