Source apportionment of airborne dioxins, furans, and polycyclic aromatic hydrocarbons at a United States forward operating air base during the Iraq War

Objectives: The objective was to apportion the sources of the ambient polycyclic aromatic hydrocarbon (PAH), polychlorinated dibenzo-p-dioxin (PCDD) and polychlorinated dibenzofuran concentrations measured at Joint Base Balad in Iraq. Methods: Positive matrix factorization (PMF) was applied to the data to obtain the chemical profiles and contribution time series of the PAHs, PCDDs, and PCDFs. Conditional probability function (CPF) analyses were performed to assess the source directionality relative to the monitoring sites. Results: Three source types were identified and apportioned. The sources were: the burn pit, diesel vehicles and generators, and aircraft emissions. The CPF plots were consistent with the assigned source types. Conclusions: The PCDDs and PCDFs originated primarily from the burn pit. Higher molecular weight PAHs were associated with vehicle emissions while the aircraft emissions were enriched in low molecular weight PAHs.