Earthdata Forum

Hi,
I was wondering if the concentrations specified in the M2T1NXAER collection were related to dry aerosol mass or if they included the water mass following their respective hygroscopic growth. If dry concentrations are specified, then shouldn't the PM2,5 formula given by [1] include the corrective hygroscopic growth factor as in [2]?
Thanks!

[1] https://gmao.gsfc.nasa.gov/reanalysis/MERRA-2/FAQ/#Q4
[2] https://gmao.gsfc.nasa.gov/pubs/docs/Collow1489.pdf

Hi,
The collection M2T1NXAER contains dry aerosol mass with a relative humidity of 0%. The equation given on the FAQ page (https://gmao.gsfc.nasa.gov/reanalysis/MERRA-2/FAQ/#Q4) will provide the dry PM2.5. Hygroscopic growth would be required for PM2.5 at a relative humidity other then 0% as recommended by https://gmao.gsfc.nasa.gov/pubs/docs/Collow1489.pdf.

Allie