PAH concentrations and exposure assessment from house dust retained in air-conditioning filters collected from Greater Doha, Qatar

PAHs and hopanes in the surface sediments of Qatar coast and their ecological risks: Comparison with regional and global coastal regions

The distribution, characteristics, sources and ecological risks of polycyclic aromatic hydrocarbons (PAHs) and hopanes in the surface sediments collected along the Qatar coast were investigated. Concentration of ∑14PAHs and hopanes ranged between 0.076 and 7.04 ng g-1 (mean: 2.60 ng g-1), 100 and 700 ng g-1 (mean: 205 ng g-1), respectively. Sediment samples were dominated by high molecular weight PAHs composition (4-6 rings). Diagnostic ratios of PAH concentrations showed both petrogenic and pyrogenic origins of PAHs, with a higher percentage of pyrogenic sources. The ecological risk levels of PAHs were estimated using sediment quality guidelines (SQG), mean probable effect level quotient values (PEL-Q), carcinogenic toxic equivalent quantity (TEQ), and risk quotient (RQ) evaluation methods. The calculated TEQ values (0.00012-0.85 ng g-1) were lesser than those in other locations around the globe, and were also within the safe level (600 ng g-1) suggested by the Canadian soil quality guidelines.

Liquid crystal monomers in ventilation and air conditioning dust: Indoor characteristics, sources analysis and toxicity assessment

Indoor dust contaminated with liquid crystal monomers (LCMs) released from various commercial liquid crystal display (LCD) screens may pose environmental health risks to humans. This study aimed to investigate the occurrence of 64 LCMs in ventilation and air conditioning filters (VACF) dust, characterize their composition profiles, potential sources, and associations with indoor characteristics, and assess their in vitro toxicity using the human lung bronchial epithelial cells (BEAS-2B). A total of 31 LCMs with concentrations (ΣLCMs) ranging from 43.7 ng/g to 448 ng/g were detected in the collected VACF dust. Additional analysis revealed the potential interactions between indoor environmental conditions and human exposure risks associated with the detected LCMs in VACF dust. The service area and working time of the ventilation and air conditioning system, and the number of indoor LCD screens were positively correlated with the fluorinated ΣLCMs in VACF dust (r = 0.355 ∼ 0.511, p < 0.05), while the associations with the non-fluorinated ΣLCMs were not found (p > 0.05), suggesting different environmental behavior and fates of fluorinated and non-fluorinated LCMs in the indoor environment. Four main indoor sources of LCMs (i.e., computer (37.1%), television (28.3%), Brand A smartphone (21.2%) and Brand S smartphone (13.4%)) were identified by positive matrix factorization-multiple linear regression (PMF-MLR). Exposure to 14 relatively frequently detected LCMs, individually and in the mixture, induced significant oxidative stress in BEAS-2B cells. Among them, non-fluorinated LCMs, specifically 3cH2B and MeP3bcH, caused dominant decreased cell viability. This study provides new insights into the indoor LCMs pollution and the associated potential health risks due to the daily use of electronic devices.

Measurement of Polycyclic Aromatic Hydrocarbons (PAHs) on Indoor Materials: Method Development

Wildfire smoke penetrates indoors, and polycyclic aromatic hydrocarbons (PAHs) in smoke may accumulate on indoor materials. We developed two approaches for measuring PAHs on common indoor materials: (1) solvent-soaked wiping of solid materials (glass and drywall) and (2) direct extraction of porous/fleecy materials (mechanical air filter media and cotton sheets). Samples are extracted by sonication in dichloromethane and analyzed with gas chromatography-mass spectrometry. Extraction recoveries range from 50-83% for surrogate standards and for PAHs recovered from direct application to isopropanol-soaked wipes, in line with prior studies. We evaluate our methods with a total recovery metric, defined as the sampling and extraction recovery of PAHs from a test material spiked with known PAH mass. Total recovery is higher for "heavy" PAHs (HPAHs, 4 or more aromatic rings) than for "light" PAHs (LPAHs, 2-3 aromatic rings). For glass, the total recovery range is 44-77% for HPAHs and 0-30% for LPAHs. Total recoveries from painted drywall are <20% for all PAHs tested. For filter media and cotton, total recoveries of HPAHs are 37-67 and 19-57%, respectively. These data show acceptable HPAH total recovery on glass, cotton, and filter media; total recovery of LPAHs may be unacceptably low for indoor materials using methods developed here. Our data also indicate that extraction recovery of surrogate standards may overestimate the total recovery of PAHs from glass using solvent wipe sampling. The developed method enables future studies of accumulation of PAHs indoors, including potential longer-term exposure derived from contaminated indoor surfaces.

An extensive assessment on the distribution pattern of organic contaminants in the aerosols samples in the Middle East

Nowadays, in spite of a significant progress in indoor air quality (IAQ), an assessable and predictive understanding of atmospheric aerosol sources, chemical composition, transformation processes, and environmental effects are still rather incomplete and therefore signifies a key research challenge in the atmospheric science. Thus, the current comprehensive review is concerned with the dominant sources, organic compositions, and potential health impacts of the organic contaminants in the atmospheric particle matters (PMs) in the Middle East (ME). The ME contributes a major impact of organic contaminants on the atmosphere along with other Asian and African countries. In the Gulf Cooperation Council (GCC) countries, the communities are noted for being the center of the great majority of the world’s oil reserves and infrastructure for producing crude oil. The review starts with a historical outlook on the scientific queries regarding major source of organic contaminants to the atmospheric aerosols over the past centuries, followed by an explanation of the distribution, sources, transformation processes, and chemical and physical properties as they are formerly assumed. Natural product chemicals from biota, manufactured organic compounds including pesticides, chlorinated hydrocarbons, and lubricants, as well as organic compounds from the use and combustion of fossil fuels make up the aerosol contamination. Thus, in the recent years, IAQ may be seen as a significant health issue because of the increase in industrial activity. Fugitive emissions from industrial processes, as well as natural and anthropogenic emissions from other sources such as forest fires, volcanic eruptions, incomplete combustion of fossil fuels, wood, agricultural waste, or leaves, are typical sources of organic pollutants to the aerosol. In the spring and early summer in the GCC countries, aerosol concentration increases because of dust storms; however, in winter, there are fewer dust storms and higher precipitation rates, and aerosol concentrations are lower. Significances of future research and major suggestions are also outlined to narrow the gap between the present understanding of the contribution of both anthropogenic and biogenic aerosols to radiative forcing, resulting from the spatial nonuniformity, intermittency of sources, unresolved composition, and reactivity.

Influence of the products of biomass combustion processes on air quality and cancer risk assessment in rural environmental (Spain)

Polycyclic aromatic hydrocarbons (PAHs) associated with atmospheric particles represent a significant risk to human health. This issue is even more relevant in environments where biomass combustion processes are considered as the major potential emission sources, such as the rural ecosystem. This study aimed to assess the levels of PM₁₀-bound PAHs in several rural locations, their distribution along a year and how weather variables could influence them. Also, we focused on the emission sources and the comparison of the PAH mixtures to assess similitude among the sampling points. PM₁₀-bound PAHs levels were monitored at three rural locations (north, center, and south) of Spain between April 2017 and February 2018. The study revealed that there were substantial differences regarding the levels of ΣPAHs, being higher in the central zone (IS; 65.4 mg/m³), then in the south (VA; 35.8 ng/m³) and finally in the north (NA; 20.9 ng/m³). IS and VA showed a similar distribution of emission sources, and temperature and wind speed seemed to influence negatively over the levels of PAHs likely. At both locations, PAH levels ran parallel throughout the year, with maximum levels during cold seasons and a greater presence of high molecular weight PAHs; however, the levels of PAHs and the most representative PAHs differed. On the other hand, NA was characterized for having another distribution of emission sources, which determined other representative PAHs, higher levels during spring, and a similar presence of high/medium/low molecular weight. Finally, the levels of ambient air PAHs represented an acceptable risk to people.

Quantification of polycyclic aromatic hydrocarbons in kitchen depositions by SUPRAS-LC-FLR and human health risk assessment

Concentration, composition and sources of polycyclic aromatic hydrocarbons (PAHs) in kitchen depositions from different sampling categories such as restaurants, university mess and houses were investigated, and associated human exposure risk through dietary intake, inhalation and dermal contact was determined. The PAHs in the samples were extracted by supramolecular solvent based microextraction (SUPRAS) method and the concentrations were determined by high pressure liquid chromatography (HPLC) with fluorescence detection. The mean of Σ16PAHs concentration was found to be the highest (386.09 ± 413.17 mg kg^-1) for restaurants followed by mess (80.91 ± 92.81 mg kg^-1) and houses (24.65 ± 10.52 mg kg^-1). Traffic sources were found to be predominant contributors of PAHs in restaurants while cooking activities were the sources for mess and houses. Three- and five-ring PAHs were prominent in restaurants and mess samples while two- and three-ring PAHs contributed the most in houses samples. Non-cancer risk (hazard index) from exposure to these PAHs was found to be within safe limits i.e. 2.70E-09 to 7.46E-08. Estimated lifetime cancer risk was found to range from 2.46E-06 to 7.81E-04 from exposure to these PAHs and indicates significant risk due to exceeding the guideline value of 10^-6.

Elemental compositions of particulate matter retained on air condition unit's filters at Greater Doha, Qatar

Elemental composition of airborne dust samples retained by internal filters of air condition units (ACUs) was determined at 12 locations of Doha city, state of Qatar. Twenty-four elements: Al, Ca, Mg, Fe, Na, K, Ti, Zn, P, Sr, Mn, Ba, Cu, Cr, Ni, Pb, V, Mo, Li, Co, Sb, As, Cd, Be, were analysed by ICP-OES technique after acid digestion of the samples. The analysed components reflect 20.6% of the total sample mass. Similar or lower concentration values have been found for As, Cd, Cr, Cu, Mn, Ni, Pb, V, Zn, Al, and Fe compared to the international context of upper crust concentrations, NIST SRM (urban dust), published local dust information of outdoor, and surface terrestrial deposit (STD) counted for 7.2, 0.7, 91.8, 192.8, 369.7, 68.6, 65.3, 52.1, 824.3, 19,791, 20,508 mg/kg, respectively. The coefficient of correlation (p ≤ 0.05) showed significant association of ACUs dust elemental compositions with the main components of the local earth crust and surface deposits, ranging from the lowest 0.77 (Mg-Fe) to the highest 0.98 (Al-Fe), while Ni and V, typical anthropogenic pollutants, are also strongly correlated (0.86). These strong correlation relationships can be interpreted as the contribution of outdoor particulate to the indoor dust. Dendrogram of metal/Al ratios, based on Euclidean distance calculation and average linkage clustering method, distinguished three typical groups. Studying the enrichment factors of the three groups indicated elevated levels of Zn (131), Pb (49), Cu (32), Cd (8) and Ni (5) found indoors compared to the background composition of STD especially at locations in the industrial zone. The major elemental composition of the samples reflects the typical mineral composition of the local dust, while the trace composition demonstrates the influence of indoor sources. The collected ACU filter dust samples show significant contribution of outdoor mineral particles, non-exhaust traffic emission, industrial sources, as well as the influence of indoor activity such as smoking.