The use of satellite observations to assess multiple airborne exposures experienced by military personnel deployed in Southwest Asia

Numerous epidemiological studies have convincingly demonstrated that exposure to airborne particulate matter (PM) poses a major risk to human health. Southwest Asia (SA) is particularly impacted by poor air quality due to several unique phenomenon that result in increased PM concentrations including dust storms, drought, extreme high temperatures, and anthropogenic pollution. Military personnel deployed to US bases in SA are additionally exposed to sources including open-pit refuse burning, heavy-duty vehicle emissions and aircraft emissions, all of which can contain toxic metals and organic compounds worsening already high ambient PM concentrations. As a result, military personnel who have served in the SA region are particularly at risk for exposure-related health issues.

By harnessing earth observations from several satellite instruments including aerosol optical depth (AOD) from the MoDerate resolution Imaging Spectroradiometer (MODIS) Multi-Angle Implementation of Atmospheric Correction (MAIAC), size-,shape-, and absorption-specific AODs from the Multi-angle Imaging SpectroRadiometer (MISR), and thermal detections from the MODIS Active Fire product, we show that we can quantify the multi-exposure profile that military personnel experienced during deployment. Specifically, with ground-level PM measurements, meteorology, and land use data, we used MAIAC to estimate daily PM2.5 concentrations at 1km spatial resolution. With ground-level speciated PM measurements, we used MISR to estimate weekly particle sulfate, nitrate, carbon and dust concentrations at 4.4 km spatial resolution. Finally, with the application of cluster algorithms to MODIS Active Fire detections, we identified areas of persistent burning near military bases that relate to burn pits.

The use of satellite observations makes it possible to retrospectively characterize airborne exposures in SA, which is of extreme importance for both understanding and safeguarding the health of military personnel deployed to the region.