Dust emission modeling using a new high-resolution dust source function in WRF-Chem with implications for air quality

Air-borne dust affects all aspects of human life. The sources of dust have high spatial variation and a better quantification of dust emission helps to identify remediation measures. Orographic and statistical source functions allow a better estimation of dust emission fluxes in coarse-scale modeling, but a high-resolution source function is necessary to represent the highly heterogeneous nature of dust sources at the finer scale. Here we use a newly developed high-resolution (~ 500 m) source function in WRF-Chem to simulate dust emission over the Middle East and North Africa, and evaluate our simulated results against observations. Using a 4 km grid spacing, we also simulate the emission and transport of dust originating from the Tigris-Euphrates basin, one of the most important regional dust sources, and quantify the effects of this source on the air quality of the entire Arabian Peninsula. Results show that the use of new source function effectively represents the key dust sources, and provides reasonable estimates of dust optical depth and concentrations. We find that the atmospheric dust originating from the Tigris-Euphrates basin alone exceeds the PM10 air quality standards in several downwind cities. Our results have broader environmental implications and indicate that the mobilization of depleted uranium (DU) deposited in Kuwait and Southern Iraq during the Gulf War (1991) could potentially affect the urban centers over the peninsula, albeit in low concentrations. Our results suggest that an integrated and coordinated management of the Tigris-Euphrates basin is necessary to maintain good air quality across the Arabian Peninsula.