Poly-fluoroalkyl substances (PFAS) are expected to accumulate in soil and potentially be picked up, transferred, and deposited during sand and dust storms (SDSs). To the researchers'SDSs. To our knowledge, there are very limited studies available on the presence of PFAS in dust, runoff, and stormwater samples ^[1][2][3][33,34,35]. Particularly in Saudi Arabia and the Arabian Gulf Region, there is a lack of scientific evidence to support the extent to which PFAS are released and transported from the paved or unpaved ground surface, where they have accumulated, to stormwater or another location. Consequently, it is essential to understand the industries, facilities, and products that significantly release PFAS into the environment, so thwe researchers ccan better identify the appropriate mitigation and adaptation measures against PFAS exposure ^[4][36].

Aqueous film-forming foam (AFFF) is a PFAS-containing firefighting foam used to quickly extinguish fire, specifically class B fires, which are petroleum fuel based and can occur at military and aviation sites ^[5][37]. Depending on the formulation, AFFF may contain diverse types of PFAS ^[6][38]. The concentrations of 17 different PFAS in the dust matrix of 49 fire stations located in Canada and the United States have been compared with the concentrations of the same PFAS in the dust collected from 184 homes in the same region ^[6][38]. The most prevalent PFAS found in the dust matrices of both homes and firefighting stations were fluorotelomer alcohols (FTOHs) and di-poly-fluoroalkyl phosphoric acid esters (diPAPs), with a median concentration of at least 100 ng/g. It was also found that PFOS and PFOA concentrations were significantly higher in fire stations’ dust, even though 8:2 FTOH was significantly higher in dust obtained from homes. PFAS flame retardants probably originating from AFFF were also detected in oil sands process-affected water (OSPW), produced by the surface-mining activities as the oil sands industry in Alberta, Canada ^[7][39]. This finding emphasizes the increased risk of such toxic materials leaching into the groundwater if left untreated ^[8][40]. Another study conducted in the United States on different environmental media showed that the concentration of PFOS was the highest at 10 active US Air Force installations ^[9][41]. These studies confirmed that fire stations, aviation sites, and military site dust are significant sources of the widespread legacy PFAS.

The majority of global emissions of some specific PFAS is attributed to fluorochemical manufacturing sites, even though there are few of these sites around the world ^[10][42]. Releases from such facilities can impact a large population and have detrimental consequences for a vast geographical area. A study conducted by Hu et al. (2016) confirmed that there are only 16 fluorochemical manufacturing plants in the USA while Prevedouros et al. (2006) reported the existence of 33 fluoropolymer production plants worldwide, spread across North America, Europe, Japan, Russia, China, and India as of 2002 ^[11][12][43,44].

The term indoor dust is used here to provide an umbrella for a variety of PFAS-containing products used in daily household, office, and business activities. PFAS have been detected in jackets, carpets, personal care products, building materials, cleansers, polishes, office desks, food contact materials, upholstery, impregnation agents, and cars ^{[13][14][15][16]}[45,46,47,48]. A detailed review by Savvaides et al. (2021) outlined the types of PFAS associated with many of the items listed above ^[17][49]. For example, FTOHs, PFCAs, PAPs, and PFSAs are often used in food packaging, as they have good resistance to water and oil. While this researchtudy seeks to find a connection between SDSs and PFAS-associated dust, it should be noted that some of these items are used daily and disposed of in open areas, which may expose them to SDSs. Other items have a significantly longer life; however, at the end of their life, they are disposed of in landfills, making the landfill another source of dust-associated PFAS. Chen et al. (2020) estimated that, in 2017, PFAS accumulated in landfilled carpets amounted to about 180 tons, while in-use carpets accumulated about 60 tons ^[18][50]. The concentration of PFAS in indoor dust may vary significantly from one location to another depending on the country’s wealth and development status. According to a study conducted by Shoeib et al. (2016), countries with high development indices, such as the USA have the highest median concentration of PFOS + PFOA in home dust, all exceeding 300 ng/g ^[19][31]. However, countries with stringent regulations regarding the use and consumption of PFAS, such as Norway, have a high human development index coupled with a very low median concentration (<50 ng/g) of PFOS + PFOA.

Wastewater treatment plants (WWTPs) often discharge treated effluents or bypass untreated or partially treated wastewater into rivers that may serve as source water for a variety of reuse purposes ^{[20][21][22][23]}[51,52,53,54]. A study conducted by Shigei et al. (2020) investigated the presence and concentration of 20 targeted PFAS in water resources within the catchment area of the Zarqa river and also the buildup of PFAS in soils and crops ^[24][55]. The point of interest here is that PFAS can accumulate in the soil matrix, especially the topsoil, as there is potential for it to be carried by wind, resulting in dermal or inhalation PFAS exposure during dust events. The first finding revealed that WWTP effluent (14–24 ng/L) has a higher concentration than the influent (10–15 ng/L), indicating PFAS poor removal. This finding signifies that the WWTP may act as a point source for PFAS in the environment. PFAS were detected in the soil matrix albeit in a generally low concentration. A similar trend was reported by Dalahmeh et al. in Uganda ^[25][56]. Sludge from WWTPs is used as fertilizer, and a study conducted by Borthakur et al. (2022) confirmed the presence of PFCA in biosolids obtained from WWTPs in the USA, Canada, Australia, and Spain ^[26][27][20,57].

Road dust is known to contain various types of contaminants that originate from vehicle exhaust emission, wear and tear of tires, litter, dust fall, accidental spills from vehicles transporting goods, biological debris, breakdown of particles from emission sources, and erosion as a result of water or wind from adjacent areas ^[28][29][58,59]. Several studies have confirmed that road dust contains contaminants such as polycyclic aromatic hydrocarbons (PAHs), pesticides, and metals ^[30][31][60,61]. In Saudi Arabia, numerous studies have confirmed the presence of heavy metals in road dust matrix, with a positive correlation with proximity to industrial sites that consume or generate trace metals ^{[32][33][34][35]}[11,12,62,63]. However, the presence of PFAS in this dust matrix has not been investigated. A study conducted by Ahmadireskety et al. (2021) investigated the presence of 37 PFAS in street sweepings in the USA by collecting 117 sweeping samples and analyzing them ^[36][64]. More than 90% of the PFAS quantified were found to be perfluoroalkyl acids (PFAAs) and their precursors, and in one site, 26 different PFAS were found; other studies confirmed the presence of PFAS in roads ^[37][38][65,66].

There are several routes by which humans and other animals may be exposed to PFAS, with the oral route being the most common. This exposure could happen through the intake of drinking water contaminated with PFAS, eating food associated with PFAS-containing products, and consumption of animal meat and plants in which PFAS have bioaccumulated. Exposure through inhalation of dust-associated PFAS, volatilized PFAS, and dermal absorption have been recorded, albeit to a lesser degree of frequency. Infants are exposed through breastmilk and in utero exposure from mothers exposed to PFAS ^{[39][40][41][42][43]}[67,68,69,70,71]. The mechanisms of transfer between PFAS in the air and dust are yet to be understood; however, it is imperative to try and reduce dust-associated exposure, especially as it is more common in children and infants, who are more likely to inhale resuspended dust in great quantities ^[17][49]. It is known that atmospheric particulate matter functions as a sink that houses atmospheric contaminants, and associated contaminants are brought to the earth’s surface via dry deposition ^[29][44][59,72]. In the MENA region, dust storms transport a significant amount of dust, which could pose a significant risk for adults and older people, who are likely to be outside during dust events. While data about the exposure of individuals or animals to PFAS in the MENA region are generally not available, studies have been conducted in other regions. For instance, the US Centers for Disease Control and Prevention (CDC) reported the presence of PFAS in the blood samples of 98% of all Americans ^[45][46][47][73,74,75]. Another study by Geisy and Kannan (2001) sought to determine the global distribution of perfluorooctanesulfonate (PFOS) in wildlife by testing tissues and blood samples from mammals, fishes, reptiles, and birds in different countries ^[48][76]. Some selected findings from the study are reported as part of Table 12. Similarly, other studies have been conducted, albeit on a relatively smaller scale, and some of the significant findings are also reported in Table 12. The studies showed the ubiquitous nature of PFAS exposure, emphasizing the immediate need to advance hazard/exposure assessments for PFAS. Additionally, these findings highlight a gap in knowledge related to similar studies in ascertaining the exposure levels t associated with the population in developing countries, as in the case of the MENA region.

Research on potential human health risks due to PFAS exposure has mainly focused on the oral route, with limited data available on the health risks associated with dermal or inhalation exposure to PFAS ^[49][77]. Studies of health effects associated with PFAS exposure have mainly included long-chain perfluorooctanoic acid (PFOA) and PFOS because short-chain PFAS are thought to be less likely to bioaccumulate, more biodegradable, and less toxic, even though there are limited toxicity data available to back up the claims ^[49][77]. Sunderland et al. (2019) reviewed several studies related to the health implications of exposure to PFAS and found there was a significant correlation between elevated PFAS exposure and dyslipidemia, a metabolic disorder related to lipid profiles, such as total cholesterol and triglycerides ^[16][48]. In some studies, metabolic diseases, such as heart disease, overweight, diabetes, and obesity, were associated with PFAS exposure, although there are inconsistencies related to the evidence supporting such claims. The carcinogenicity of PFAS, immunotoxicity, and neurodevelopment deficiency have also been investigated, with most of these studies conducted on animals, such as rodents. Translating the results to human exposure tends to be very challenging because one of the main toxicity mechanisms of PFAS is peroxisome proliferation expression, which differs between humans and rodents. Nevertheless, studies conducted on rodents have shown that exposure to PFAS can cause liver disease, immune issues, thyroid disease, and cancer, as well as adverse effects on fetuses during pregnancy ^[50][51][78,79]. For these reasons, the US Environmental Protection Agency (US EPA) recently classified PFOA and PFOS as part of the fourth Contaminant Candidate List ^[49][77].