Aerosols as Vectors for Contaminants: A Perspective Based on Outdoor Aerosol Data from Kuwait

Abstract

The Middle East is a hot spot of dust, and there are reports of as much as 1400 µg m−3 of dust in aerosols from Kuwait, which is among some of the highest dust loadings globally. A significant volume of literature has emerged on dust–air-quality–human-health, and the World Health Organization in its recent air quality guidelines has lowered the limit of annual PM2.5 exposure to 5 μg m−3 from the previous limit of 10 μg m−3. We present a mini-review based on a screening and search of the published data generated in Kuwait on contaminants associated with dust in different size fractions. We also include an unpublished study on organic contaminants in size-fractionated aerosols. The ΣPAHs concentrations in all the six size fractions range between 570 and 3350 pg m−3. The ∑PBDE concentration ranges from ~2 to 1307 pg m−3. The average 210Po activity in aerosol size classes varies between 2289 and 2581 Bq kg−1. The average 210Pb concentration varies between 352 and 412 Bq kg−1. The MP inventory in Kuwait’s outdoor aerosol is between 5 and 35 MP in 815 ± 5 m3 of air. The bacterial load in outdoor aerosols is between 6.05 × 103 cells m−3 and 1.24 × 108 cells m−3. The fungal load ranges between 2.11 × 102 cells m−3 and 2.66 × 106 cells m−3. The data suggest that the inhalable fraction of <2.5 µm size contains high concentrations of Polycyclic Aromatic Hydrocarbons (PAHs), Polybrominated diphenyl ethers (PBDEs), 210Po, 210Pb, microplastics, and microbes. These enriched ultrafine aerosols pose a significant risk to human health. The review also highlights the scarcity of contaminant data in respirable and inhalable size fractions that are critical for a comprehensive inhalation risk assessment.