Atmospheric particulate matter (PM) pollution levels and human health risks resulting from exposure to non-anthropogenic pollution sources, such as coal mine-fires, are serious global issues. The toxicity of PM₁₀-bound metals and polycyclic aromatic hydrocarbons (PAHs) was assessed according to their non-cancer and cancer risks (CRs) at the mine-fire and in an adjacent city area. Health risks were estimated for inhalation, ingestion, and dermal absorption pathways. The non-cancer risks, presented in terms of the hazard index (HI) and hazard quotient (HQ), were found to be significant (>1) at all locations, except in the mining (for HQ-dermal) and city background area (for HQ-ingestion and HQ-dermal) in children and adults, respectively. The total CR was estimated to be highest at the city nearby the mine-fire area (3.31E-02 and 1.93E-02) followed by the mine-fire area (2.66E-02 and 1.71E-02) for children and adults, respectively. The total CR and CR via individual exposure routes were estimated to be in the high risk (10⁻³ ≤ CR < 10⁻¹) category at the mine-fire site and adjacent city area. For all exposures, CR levels were calculated to be higher than the acceptable range (from 1.00E-06 to 1.00E-04), except for the CR-inhalation level at the A5 location. Among all elements, Cd and BaPₑqᵤ were more significant for the CR at the coal mine-fire and the adjacent city area. Hence, this study concluded that non-anthropogenic sources, such as coal mine-fires, could be part for the significant health risk (carcinogenic and non-carcinogenic) levels in the study area.

Inspired by methods used for life cycle impact assessment (LCIA), we constructed a series of indicators to appreciate the noxiousness of radioactive materials and wastes for human and ecosystem health. According to known potential human health and ecological effects of such materials, six main impact categories were considered to initiate the development of the method: human cancer and non-cancer effects vs. ecotoxicity, considering both chemotoxicity and radiotoxicity. For ecosystems, the noxiousness indicator is based on the concept of Potentially Affected Fraction (PAF), used as a damage indicator at the ecosystem level. The PAF express the toxic pressure on the environment due to one substance. It has been enlarged to mixtures of substances as multi-substances PAF (ms-PAF), and applied to a mix of stable and radioactive substances. Combining ecotoxicity data and a simplified model of exposure of fauna and flora, we proposed a chemotoxicity indicator and a radiotoxicity indicator, ultimately aggregated into a single indicator simply by addition.According to acknowledged practices in LCIA and corresponding available data, we suggested implementing to human health an approach similar to that applied to ecosystems. We produced eigth basic indicators combining effects categories (cancer and non cancer), exposure pathways (ingestion and inhlation) and substances (chemicals and radionuclides). The principle of additivity supporting the whole proposed approach allows their complete aggregation into a single indicator also for human health. Different source terms may be then easily directly compared in terms of human and ecological noxiousness.Applied to the time evolution of a High Level radioactive Waste (HLW), the method confirmed over 1 million years the dominance of the radiotoxicity in the noxiousness of the material for both humans and environment. However there is a change with time in the ranking of the most noxious substances, with stable metals contribution going progressively up. Finally, the HLW global noxiousness, integrating human health and ecological aspects, was assessed through time at three stages and showed a temporal decrease as expected from the dominance of the radiotoxicity.

This study aimed to assess the carcinogenic and non-carcinogenic risks of in-vehicle exposure in Tehran, Iran to formaldehyde and acetaldehyde for different models of taxis, and to explore the effects of city zone, taxi vehicle type, the taxi's age (<1, 1–5, 5–10), fuel type (gasoline, CNG, and LPG), and refueling activities on the estimated health risks based on previously measured concentrations. The overall and age-specific carcinogenic and non-carcinogenic risks of these compounds for taxi drivers and passengers were estimated separately using Monte Carlo simulations. Three scenarios of exposure frequency were defined for taxis commuting in different zones of city: Restricted Traffic Zone (RTZ) and Odd-Even Zone (OEZ) as two plans to reduce air pollution, and no-restriction zone (NRZ). The carcinogenic risks for drivers and passengers, the average risks of formaldehyde and acetaldehyde for most cases were above the 1 × 10⁻⁴. The health risks were greater in Restricted Traffic Zone (RTZ) and Odd-Even Zone (OEZ) in comparison to no-restriction zone (NRZ). The carcinogenic risk from formaldehyde exposures were higher than those for acetaldehyde in all cases. Taxis fueled with LPG showed lower cancer risks for both acetaldehyde and formaldehyde. Refueling increased the carcinogenic risk from both compounds. For non-carcinogenic risks from acetaldehyde, the average hazard ratios for both drivers and passengers were >1, indicating a non-negligible risk. Cancer and non-cancer risks for the taxi drivers were greater than the passengers given the higher time of occupancy. The present study showed that transportation in taxis can impose significant long-term health risks to both passengers and drivers. Development and investment in cleaner choices for public transportations are required.

Environmental contaminants, to which humans are widely exposed, cause or worsen several diseases, like cardiovascular diseases and cancers. Among these molecules, polycyclic aromatic hydrocarbons (PAHs) stand out since they are ubiquitous pollutants found in ambient air and diet. Because of their toxic effects, public Health agencies promote development of research studies aiming at increasing the knowledge about PAHs and the discovery of biomarkers of exposure and/or effects.Extracellular vesicles (EVs), including small extracellular vesicles (S-EVs or exosomes) and large extracellular vesicles (L-EVs or microvesicles), are delivery systems for multimolecular messages related to the nature and status of the originating cells. Because they are produced by all cells and detected within body fluids, EV releases could act as cell responses and thereby serve as biomarkers.To test whether EVs can serve as biomarkers of PAHs exposure, we evaluate the effects of these pollutants on EV production using an in vitro approach (human endothelial cell line, HMEC-1) and an in vivo approach (urine samples from PAHs-exposed rats). Our study indicates that, i) PAH exposure increases in vitro the EV production by endothelial cells and in vivo the release of EVs in urine, and that the stimulating effects of PAHs concern both S-EVs and L-EVs; ii) PAH exposure and more particularly exposure to B[a]P, can influence the composition of exosomes produced by endothelial cells; iii) the aryl hydrocarbon receptor, a cytosolic receptor associated to most deleterious effects of PAHs, would be involved in the PAH effects on the release of S-EVs, but not L-EVs.These results suggest that EVs may have utility for monitoring exposure to PAHs, and more particularly to B[a]P, considered as reference PAH, and to detect the related early cellular response prior to end-organ damages.

This study characterized spatio-temporal variations in the concentration of benzene, toluene, ethylbenzene, and xylene (BTEX) compounds in the vicinity of gas and compressed natural gas (CNG) stations in Tehran, Iran. Health risk assessment (HRA) was computed using Monte Carlo simulations (MCS) for evaluating inhalation lifetime cancer risk (LTCR), the hazard quotient (HQ), and sensitivity analysis (SA) for BTEX exposure in different age groups (birth to <81) and as a function of distance (0–250 m) from the center of the stations. For all monitoring stations, the average values of benzene, toluene, ethylbenzene, and xylene in winter were 466.09 ± 132.25, 873.13 ± 233.51, 493.05 ± 141.22, and 910.57 ± 145.40 μg m⁻³, respectively. The mean wintertime ratios of T/B for the 12 stations ranged from 1.69 to 2.04. Furthermore, there was no significant relationship between the concentration of BTEX with either the specific month or distance from the center of stations (p > 0.05). Factors promoting BTEX formation in the study region were fuel evaporation and gas/CNG station emissions. The LTCRs for the target compounds in the winter for different age groups and distances from the center of stations was limited to 2.11 × 10⁻⁴ to 1.82 × 10⁻³ and 2.30 × 10⁻⁴ to 2.01 × 10⁻³, respectively, which exceeded proposed values by U.S. EPA. Moreover, the HQs for BTEX for three age groups and distances were limited to between 2.89 × 10⁻⁵ and 9.33 × 10⁻², which were lower than the acceptable limit (HQs < 1). The results of this work are applicable to similar areas that are heavily populated with vehicular traffic. This study motivates a closer look at mitigation strategies to limit the health effects of carcinogenic emissions such as benzene and ethylbenzene from gas/CNG stations.

Inhalation exposure to flame retardants used as additives to minimize fire risk and plasticizers is ubiquitous in human daily activities, but has not been adequately assessed. To address this research gap, the present study conducted an assessment of human health risk for four age groups through inhalation exposure to size fractionated particle-bound and gaseous halogenated flame retardants (polybrominated diphenyl ethers (PBDEs) and alternative halogenated flame retardants (AHFRs)) and organophosphate esters (OPEs) at indoor and outdoor environments (school, office, and residence) in three districts of a megacity (Guangzhou, China). Results demonstrated that OPEs were the dominant components among all targets. Indoor daily intakes of PBDEs and OPEs were 13–16 times greater than outdoor levels for all age groups. Gaseous OPEs contributed significantly greater than particle-bound compounds to daily intakes of all target compounds. Based on the different life scenarios, hazard quotient (HQ) and incremental life cancer risk (ILCR) from adults exposure to PBDEs and OPEs in indoor and outdoor settings were the greatest, followed by adolescents, children, and seniors. The estimated HQ and ILCR for all age groups both indoors and outdoors were lower than the safe level (HQ = 1 and ILCR = 10−6), indicating that the potential health risk for local residents in Guangzhou via inhalation exposure to atmospheric halogenated flame retardants and OPEs was low.

Gaseous and particulate polycyclic aromatic hydrocarbons (PAHs) and size-segregated particulate matter (PM) in indoor air and outdoor air, along with personal exposure, were monitored in rural households of Northern China. The daily average concentrations of 28 species were 1310 ± 811, 738 ± 321, 465 ± 247, and 655 ± 250 ng/m3 in kitchen air, bedroom air, and outdoor air, and for personal exposure, respectively. PAHs tended to occur in the particulate phase with increasing molecular weight. Absorption by particulate organic carbon was dominant in the gas-particle partitioning process. The daily averaged concentrations of PM2.5 and PM1.0 were 104 ± 39.5 and 88.4 ± 39.3 μg/m3 in kitchen air, 79.0 ± 63.2 and 65.7 ± 57.5 μg/m3 in bedroom air, 52.9 ± 16.5 and 41.5 ± 12.5 μg/m3 in outdoor air, and 71.7 ± 30.8 and 61.5 ± 28.4 μg/m3 for personal exposure, respectively. The non-priority components contributed 5.5 ± 2.8% to the total PAHs, while their fraction of carcinogenic risk reached 85.6 ± 6.9%. The mean cancer risk posed to rural residents via inhalation exposure to PAHs exceeded the current acceptable threshold of 1.0 × 10−6 and the national average estimated in China. The personal exposure levels of PAHs and PM in households using clean energy were lower than those in households using traditional biomass by 30.0%, 29.4%, and 38.5% for PAH28, PM2.5, and PM1.0, respectively. However, the cancer risk of personal inhalation exposure to PAH28 from using liquid petroleum gas (LPG) was higher than that from using firewood, implying the adoption of LPG may not effectively reduce the cancer risk despite the decreasing exposure levels of PAH28 and PM with respect to the use of firewood. Cooking individuals suffered higher exposure levels of PAH28 and PM1.0 compared with non-cooking individuals, and the cancer risk of personal inhalation exposure to PAH28 for cooking individuals was 1.7 times that for non-cooking individuals. Cooking was a critical factor that affected the personal exposure levels of the local male and female residents.

Passive air sampling was conducted in Toronto and the Greater Toronto Area from 2016 to 2017 for 6 periods, in order to investigate ambient levels of polycyclic aromatic compounds (PACs) associated with different source types. The selected sampling sites (n = 8) cover geographical areas with varying source emissions including background, traffic, urban, industrial and residential sites. Passive air samples were analyzed for PACs which include PAHs, alkylated PAHs (alk-PAHs), dibenzothiophene and alkylated dibenzothiophenes (DBTs) and results for PAHs were used to calculate inhalation cancer risks using different approaches. The samples were also characterized for PAH derivatives including nitrated PAHs (NPAHs) and oxygenated PAHs (OPAHs). Concentrations of Σalk-PAHs and DBTs, which are known to be enriched in fossil fuels, as well as ΣNPAHs, were highest at a traffic site (MECP) located adjacent to the 18-lane Highway 401 that runs across Toronto. Except for an industrial site (HH/BU), PAC compositions were similar across the sampling sites with Σalk-PAHs being the most abundant class of PACs suggesting traffic emission was a major contributor to PACs in the atmosphere of Toronto. The industrial site exhibited a distinct chemical composition with ΣPAHs dominating over Σalk-PAHs and with elevated levels of fluoranthene, 9-nitroanthracene, and 9,10-anthraquinone, which likely reflects emissions from nearby industrial sources. MECP and HH/BU exhibited higher lifetime excess inhalation cancer risks indicating an association with traffic and industrial sources. The importance of the traffic sector as a source of PACs to ambient air is further supported by strong correlations of the ΣPAHs, Σalk-PAHs, DBTs, and ΣOPAHs with NOx. This study highlights the importance of traffic as an emission source of PACs to urban air and the relevance of PAC classes other than just unsubstituted PAHs that are important but currently not included in air quality guidelines or for assessing inhalation cancer risks.

Parent polycyclic aromatic hydrocarbons (PPAHs) in the ambient air of the coastal cities near the Bohai and Yellow Seas were measured over a full year. The range and geometric average of total PPAH₂₉ (29 species) were 5.16-1.22 × 10³ and 118 ng/m³, respectively, with 77 ± 14% in a gaseous phase. The 16 priority components accounted for 90 ± 4% of the total mass concentration. The incremental life cancer risk (ILCR) via inhalation exposure to the PPAHs (3.17 × 10⁻⁴) was underestimated by 80%, as only the priority PPAHs were considered. The air concentrations of PPAHs in the Bohai Sea area were generally higher (p < 0.01) than those in the Yellow Sea area. A significant increase (p < 0.01) in the levels of PPAHs and large fractions of high molecular weight (HMW) components were observed in winter. Absorption by particulate organic carbon dominated in gas-particle partitioning of the PPAHs, and the seasonal variations in gas-particle partitioning of the low and moderate molecular weight compounds were more noticeable relative to the HMW species. In summer, significantly higher concentrations of PPAHs were found in the daytime than during nighttime, while the opposite case occurred in winter (p < 0.05). The positive matrix factorization (PMF) results indicated greater contributions of coal and biomass combustion to the PPAH emissions in the coastal cities of the Bohai Sea area compared with the Yellow Sea area. The burning of coal and biomass served as the main source of PPAHs in winter, while traffic exhaust was the dominant source in other seasons. The potential source contribution function (PSCF) revealed the important impacts of the external inputs on the local PPAHs via air mass transport. The contributions of the resolved emission sources to the ILCR were clearly different from those of the mass concentrations, indicating the necessity for source-oriented risk assessments.

Mangroves act as sinks for terrigenous pollutants to alleviate their influence on offshore marine ecosystem. The nationwide study of PBDEs contamination in mangrove wetlands of China has not been explored, and their risk for human health lack quantitative analysis. In this study, sediment samples were collected in six mangrove wetlands along coastal area of South China to evaluate the levels, congener distributions and ecological risks of eight PBDEs, including BDE-28, -47, −99, −100, −153, −154, −183, and −209. Levels of ∑PBDEs (the sum of seven PBDEs except BDE-209) and BDE-209 were 0.13–2.18 ng g−1 and 1.44–120.28 ng g−1, respectively. In particular, mean level of BDE-209 was highest in Futian, followed by Yunxiao, Fangchenggang, Zhanjiang, Dongzhaigang, and Dongfang. As dominant PBDE congener, BDE-209 accounted for 63.6%–99.1% of the total PBDEs, suggesting the major sources of commercial deca-BDE mixtures. Among seven PBDE congeners except BDE-209, slightly different percentages of PBDE congeners were detected, with BDE-154, -47, and −100 being predominant congeners. Positive relationship was observed for total organic matter (TOM) with BDE-209, with no such relationships found for particle size compositions (clay, silt and sand). As for sediment-dwelling organism, the ecological risks from tri-, tera-, and hexa-BDE congeners could be negligible, and those from penta- and deca-BDE congeners were low or moderate, indicating major ecological risk drivers of penta- and deca-BDE congeners in mangrove wetlands in China. The ecological risk of PBDEs in mangrove sediments for human health was thought to be consumption of fish which would bioaccumulate PBDEs from the contaminated sediment. As for human health, the levels of non-cancer risks of PBDEs were all lower than 1, and the cancer risk was far less than the threshold level (10−6), demonstrating low risk for human health.