Exposures to combustion sources near military operations in Iraq and Afghanistan using satellite observations

Abstract

U.S. military personnel deployed to Afghanistan and Iraq were stationed on bases impacted by airborne hazards including emissions from combustion sources. Due to limited environmental monitoring during military operations, exposure levels remain poorly characterized. We used satellite observations to identify the locations and persistence of combustion sources on and near military bases in Afghanistan and Iraq from 2002 to 2012, the peak period of open-air combustion. Daily fire detections from the Moderate Resolution Imaging Spectroradiometer (MODIS) were clustered using density-based methods to identify persistent burning within 5 km of bases. Validation was conducted using military imagery and Google Earth. A sensitivity analysis compared MODIS fire detections to those from the newer Visible Infrared Imaging Spectroradiometer (VIIRS) at a civilian burn pit in Djibouti. MODIS detected 285,810 fires in Iraq and 3702 in Afghanistan. Clustering identified 398 bases in Iraq and 122 in Afghanistan with burning nearby. In Iraq, persistent clusters were linked to oil and gas flares, while smaller clusters on bases in both countries were consistent with burn pits. MODIS and VIIRS both detected the Djibouti burn pit, but VIIRS recorded three times more fire detections, highlighting its sensitivity in detecting biomass and waste burning.