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Thank you for your interest in MERRA-2 aerosol data! You are correct in your understanding of the fields. SSSMASS, DUSMASS, BCSMASS, and OCSMASS include all five size bins for sea salt and dust, and both hydrophobic and hydrophilic for black and organic carbon. SSSMASS25 and DUSMASS25 only contain t...

Hello, thank you for your interest in the MERRA-2 aerosol products! A major contributor to organic carbon, and to a lesser extent, black carbon and sulfate, is biomass burning.Volcanoes also emit sulfur dioxide which forms sulfate aerosol. Therefore, components of all aerosol species in MERRA-2 can ...

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 recomme...

Hello, I am chiming in to confirm that there was a change in the source data for biomass burning emissions in 2010 in MERRA-2. Prior to 2010, emissions were monthly and scaled to GFEDv3.1 on a global scale. Beginning in 2010, emissions are daily from QFEDv2.4r6. The source data can be used to determ...

Hello, Thank you for your interest in using MERRA-2 to compute PM2.5. GEOS is constantly evolving over time as advancements are made to the underlying model, including the GOCART aerosol module. Reanalyses such as MERRA-2 use a frozen version of the model so that the long term time series is consist...

The equation to calculate PM10 is listed in the answer to FAQ #5 on the MERRA-2 FAQ page at https://gmao.gsfc.nasa.gov/reanalysis/MERRA-2/FAQ/#. PM10 = (1.375*SO4 + BCphobic + BCphilic + OCphobic + OCphilic + DU001 + DU002 + DU003 + 0.74 * DU004 + SS001 + SS002 + SS003 + SS004) * AIRDENS Time-averag...