Assessment of the impact of discontinuity in satellite instruments and retrievals on global PM₂.₅ estimates





Citation of Original Publication

Hammer, Melanie S., Aaron van Donkelaar, Liam Bindle, Andrew M. Sayer, Jaehwa Lee, N. Christina Hsu, Robert C. Levy, et al. “Assessment of the Impact of Discontinuity in Satellite Instruments and Retrievals on Global PM₂.₅ Estimates.” Remote Sensing of Environment 294 (August 15, 2023): 113624.


This work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.
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Exposure to fine particulate matter (PM₂.₅) is the leading environmental risk factor for mortality globally. Satellite-derived estimates of surface PM₂.₅ developed from a combination of satellites, simulations, and ground monitor data are relied upon for health impact studies. The ability to develop satellite-derived PM₂.₅ estimates requires the continued availability of aerosol optical depth (AOD) sources. This work examines the impact of the addition or loss of satellite AOD data sources on global PM₂.₅ estimation and the impact of continuing the long-term record with AOD from the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi-National Polar orbiting Partnership (S-NPP) satellite after the loss of the MODIS (MODerate resolution Imaging Spectroradiometer) and MISR (Multi-angle Imaging Spectroradiometer) instruments on board the Terra and Aqua satellites. We find that the addition of VIIRS S-NPP AOD products to geophysical PM₂.₅ estimates from satellites and simulations causes regional differences that correspond to differences in the VIIRS and MODIS Deep Blue AOD algorithms and sampling. Changes in long-term trends and timeseries due to the addition or loss of AOD data sources are generally within their uncertainties. Statistical fusion with ground monitor data partially corrects for changes due to sampling differences when introducing the VIIRS AOD products, but uncertainty remains over desert regions where ground monitor coverage is sparse. This work provides promise for the sustained development of global satellite-derived PM₂.₅ estimates, despite discontinuities in instruments and retrieval methods.