Characteristics of polycyclic aromatic hydrocarbons in indoor and outdoor atmosphere in the North central part of India

Polycyclic Aromatic Hydrocarbons (PAHs) in the Environment: Occupational Exposure, Health Risks and Fertility Implications

Polycyclic aromatic hydrocarbons (PAHs) are a group of organic compounds with fused aromatic rings, primarily derived from combustion processes and environmental pollutants. This narrative review discusses the most relevant studies on PAHs, focusing on their sources, environmental and occupational exposure, and effects on human health, emphasizing their roles as carcinogenic, mutagenic, and teratogenic agents. The primary pathways for human exposure to PAHs are through the ingestion of contaminated food (mainly due to some food processing methods, such as smoking and high-temperature cooking techniques), the inhalation of ambient air, and the smoking of cigarettes. Coke oven workers are recognized as a high-risk occupational group for PAH exposure, highlighting the need for appropriate strategies to mitigate these risks and safeguard worker health. PAHs are metabolized into reactive intermediates in the body, which can lead to DNA damage and promote the development of various health conditions, particularly in environments with high exposure levels. Chronic PAH exposure has been linked to respiratory diseases, as well as cardiovascular problems and immune system suppression. Furthermore, this review underscores the significant impact of PAHs on reproductive health. The results of the reported studies suggest that both male and female fertility can be compromised due to oxidative stress, DNA damage, and endocrine disruption caused by PAH exposure. In males, PAHs impair sperm quality, while, in females, they disrupt ovarian function, potentially leading to infertility, miscarriage, and birth defects. Fetal exposure to PAHs is also associated with neurodevelopmental disorders. Given the extensive and detrimental health risks posed by PAHs, this review stresses the importance of stringent environmental regulations, occupational safety measures, and public health initiatives to mitigate exposure and safeguard reproductive and overall health.

Review of polycyclic aromatic hydrocarbons pollution characteristics and carcinogenic risk assessment in global cooking environments

In recent years, research on air pollution in cooking environments has gained increasing attention, particularly studies related to polycyclic aromatic hydrocarbons (PAHs) pollution. Hence, it is crucial and urgent to conduct a comprehensive review of research findings and further evaluate their carcinogenic risks. This study adopts a comprehensive literature review approach, systematically integrating and deeply analyzing the conclusions and data from 62 selected relevant studies. It focuses on the impact of different factors on PAHs concentrations, considers the indoor-outdoor PAHs concentration ratio, and conducts carcinogenic risk assessments for PAHs. The results show that Africa has the highest average PAHs pollution concentration globally at 14.74 μg/m³, exceeding that of other continents by 1.5-160.9 times. Among various influencing factors, fuel type has the most significant impact on PAHs concentrations. Existing research data indicate that cooking with charcoal as fuel produces the highest PAHs concentration at 223.52 μg/m³, with high molecular weight PAHs accounting for 58.16%, significantly higher than when using clean energy. Furthermore, efficient ventilation systems have been proven to substantially reduce PAHs concentrations, with a reduction rate of up to 88.1%. However, cooking methods and food types also have a small but non-negligible impact on PAHs production. Using mild cooking methods such as steaming and selecting low-fat foods can also reduce PAHs to some extent. Additionally, through the analysis of the Indoor/Outdoor ratio, it was found that cooking is the primary source of indoor pollution, and the average concentration of PAHs in cooking environments in Asia and Africa is much higher than in Europe and America. The Total Incremental Lifetime Cancer Risk (TILCR) exceeds 10⁻⁴, indicating a high level of carcinogenic risk.

Emissions of Semi-Volatile Organic Compounds from Architectural Coatings and Polyvinyl Chloride Floorings: Microchamber Method

Semi-volatile organic compounds (SVOCs) are modern chemical substances that are present in large quantities in indoor environments. Understanding the emission of SVOCs from building materials is essential to identify the main sources of indoor SVOCs and to improve indoor air quality. In this study, a reference method employing custom-designed microchambers (630 mL) was optimized by improving the structure of the gas path and adding polytetrafluoroethylene inner coating to the chamber. After optimization, the recoveries of the microchamber method were significantly improved (75.4-96.7%), and the background in the microchamber was greatly reduced (<0.02 μg/h). By using the microchamber method, 33 SVOCs (including two alkanes, one aromatic, one nitrogen compound, and twenty-nine oxygenated compounds) and 32 SVOCs (including seven alkanes, eight aromatics, and seventeen oxygenated compounds) were detected in the emissions of the architectural coating and the PVC flooring samples, respectively. The area-specific emission rates (SERa) of total SVOCs emitted from architectural coatings and PVC floorings were in the range of 4.09-1309 μg/m2/h) (median: 10.3 μg/m2/h) and 0.508-345 μg/m2/h (median: 11.9 μg/m2/h), respectively. Propanoic acid had the highest SERa (3143 μg/m2/h) in architectural coatings, while methylbenzene (345 μg/m2/h), 2-methylnaphthalene (65.2 μg/m2/h), and naphthalene (60.3 μg/m2/h) were main SVOCs emitted from PVC floorings. Meanwhile, the average second-stage (adsorbed phase) emission mass of the total SVOCs accounts for 66.3% and 47.3% in architectural coatings and PVC floorings, respectively, suggesting that the SVOCs emitted from building materials have a strong tendency to be absorbed on the surface of the room, e.g., the interior wall, the desk or even the skin.

Distribution of polycyclic aromatic hydrocarbons in indoor/outdoor window films and the indoor film/air partition of northeastern Chinese college dormitories

Indoor window films can represent short-term air pollution conditions of indoor environment through rapidly capturing organic contaminants as effective passive air samplers. To investigate the temporal variation, influence factors of polycyclic aromatic hydrocarbons (PAHs) in indoor window films, and the exchange behavior with gas phase in college dormitories, 42 pairs window films of interior and exterior window surfaces and corresponding indoor gas phase and dust samples were collected monthly in six selected dormitories, Harbin, China, from August to December 2019 and September 2020. The average concentration of ∑₁₆PAHs in indoor window films (398 ng/m²) was significantly (p < 0.01) lower than that in outdoors (652 ng/m²). In addition, the median indoor/outdoor ∑₁₆PAHs concentration ratio was close to 0.5, showing that outdoor air acted as a major PAH source to indoor environment. The 5-ring PAHs were mostly dominant in window films whereas the 3-ring PAHs contributed mostly in gas phase. 3-ring PAHs and 4-ring PAHs were both important contributors for dormitory dust. Window films showed stable temporal variation, i.e. PAH concentrations in heating months were higher than those in non-heating months. The atmospheric O₃ concentration was the main influence factor of PAHs in indoor window films. PAHs with low molecular weight in indoor window films rapidly reached film/air equilibrium phase within in dozens of hours. The large deviation in the slope of the log K_F-A versus log K_OA regression line from that in reported equilibrium formula might be the difference between the window film composition and octanol.

Bioinorganic Nanoparticles for the Remediation of Environmental Pollution: Critical Appraisal and Potential Avenues

Nowadays, environmental pollution has become a critical issue for both developed and developing countries. Because of excessive industrialization, burning of fossil fuels, mining and exploration, extensive agricultural activities, and plastics, the environment is being contaminated rapidly through soil, air, and water. There are a variety of approaches for treating environmental toxins, but each has its own set of restrictions. As a result, various therapies are accessible, and approaches that are effective, long-lasting, less harmful, and have a superior outcome are extensively demanded. Modern research advances focus more on polymer-based nanoparticles, which are frequently used in drug design, drug delivery systems, environmental remediation, power storage, transformations, and other fields. Bioinorganic nanomaterials could be a better candidate to control contaminants in the environment. In this article, we focused on their synthesis, characterization, photocatalytic process, and contributions to environmental remediation against numerous ecological hazards. In this review article, we also tried to explore their recent advancements and futuristic contributions to control and prevent various pollutants in the environment.

PAHs bound to submicron particles in rural Chinese homes burning solid fuels

Inhalation exposure to polycyclic aromatic hydrocarbons (PAHs) from indoor solid fuel combustion poses a high health risk, and PAHs bound to particles with smaller sizes (e.g., PM_1.0, aerodynamic diameter ≤ 1.0 µm) should be of particular concern since they can penetrate deep into pulmonary alveoli. However, PAHs bound to PM_1.0 was less studied compared with PAHs in total suspended particles or PM_2.5. In this study, multiple provincial field measurements were conducted to investigate 28 PAHs bound to PM_1.0 in rural Chinese homes. Daily averaged PM_1.0-PAH₂₈ concentrations ranged from 27 ng/m³ to 3795 ng/m³ (median: 233 ng/m³) and from 10 ng/m³ to 2978 ng/m³ (median: 87 ng/m³) in indoor and outdoor air, respectively. Higher concentrations were found in northern China in winter due to increased solid fuels consumption for space heating. The ambient pollution was lower during the non-heating season in Eastern China, where clean energy was preferred. Highly toxic congeners were more abundant in indoor air compared with outdoor air. The results of source apportionment revealed that solid fuel combustion was the primary contributor to rural household PM_1.0-PAHs, but other sources such as vehicles cannot be overlooked. The transition to cleaner energy can reduce the indoor PM_1.0-PAH₂₈ and BaP_eq-28 concentrations by 87% and 98%, respectively, and more efficient reduction was observed for highly toxic congeners. The estimated Incremental Lifetime Cancer Risk (ILCR) based on PM_1.0-PAH₂₈ ranged from 4.6 × 10^-5 to 3.4 × 10^-2, far exceeding the acceptable level of 10^-6. Over 60% of the ILCR could be attributed to inhalation exposure during childhood and adolescence.

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.

A case study on the occurrence of polycyclic aromatic hydrocarbons in indoor dust of Serbian households: Distribution, source apportionment and health risk assessment

This study was conducted in order to obtain the first insight into the occurrence, potential sources, and health risks of polycyclic aromatic hydrocarbons (PAHs) in indoor dust. Samples (n = 47) were collected from households in four settlements in the northern Serbian province of Vojvodina. Total concentrations of 16 EPA priority PAHs in the dust samples varied from 140 to 8265 μg kg^-1. Mean and median values for all samples were 1825 and 1404 μg kg^-1, respectively. According to the international guidelines for indoor environment, PAH content can be regarded as normal (<500 μg kg^-1) for ∼6% of the samples, high (500-5000 μg kg^-1) for ∼87% of the samples, and very high (5000-50000 μg kg¹) for ∼6% of the samples. In all settlements, PAHs with 4 rings were the most prevalent (accounting for 40-53% of the total PAHs). They were followed by 3-ringed PAHs (29-40%), which indicates rather uniform PAH profiles in the analyzed dust. Based on diagnostic ratios, principal component analysis (PCA), and positive matrix factorization (PMF), pyrogenic sources, such as vehicle emissions and wood combustion were the dominant sources of PAHs in analyzed samples. Health risk assessment, which included incidental ingesting, inhaling and skin contact with PAHs in the analyzed dust, was evaluated by using the incremental lifetime cancer risk (ILCR) model. Median total ILCR was 3.88E-04 for children, and 3.73E-04 for adults. Results revealed that major contribution to quite high total ILCRs was brought by dermal contact and ingestion. Total cancer risk for indoor dust indicated that 85% of the studied locations exceeded 10-4. This implies risk of high concern, with potential adverse health effects. The results are valuable for future observation of PAHs in indoor environment. They are also useful for regional authorities who can use them to create policies which control sources of pollution.

Predictors of urinary polycyclic aromatic hydrocarbon metabolites in girls from the San Francisco Bay Area

BACKGROUND

Polycyclic aromatic hydrocarbon (PAH) exposures from tobacco smoke, automobile exhaust, grilled or smoked meat and other sources are widespread and are a public health concern, as many are classified as probable carcinogens and suspected endocrine-disrupting chemicals. PAH exposures can be quantified using urinary biomarkers.

METHODS

Seven urinary metabolites of naphthalene, fluorene, phenanthrene, and pyrene were measured in two samples collected from girls aged 6-16 years from the San Francisco Bay Area. We used Spearman correlation coefficients (SCC) to assess correlations among metabolite concentrations (corrected for specific gravity) separately in first (n = 359) and last (N = 349) samples, and to assess consistency of measurements in samples collected up to 72 months apart. Using multivariable linear regression, we assessed variation in mean metabolites across categories of participant characteristics and potential outdoor, indoor, and dietary sources of PAH exposures.

RESULTS

The detection rate of PAH metabolites was high (4 metabolites in ≥98% of first samples; 5 metabolites in ≥95% of last samples). Correlations were moderate to strong between fluorene, phenanthrene and pyrene metabolites (SCC 0.43-0.82), but weaker between naphthalene and the other metabolites (SCC 0.18-0.36). SCC between metabolites in first and last samples ranged from 0.15 to 0.49. When classifying metabolite concentrations into tertiles based on single samples (first or last samples) vs. the average of the two samples, agreement was moderate to substantial (weighted kappa statistics 0.52-0.65). For specific metabolites, concentrations varied by age, race/ethnicity, and body mass index percentile, as well as by outdoor sources (season of sample collection, street traffic), indoor sources (heating with gas, cigarette smoke), and dietary sources (frequent use of grill, consumption of smoked meat or fish) of PAH exposures.

CONCLUSIONS

Urinary PAH exposure was widespread in girls aged 6-16 years and associated with several sources of exposure. Tertile classification of a single urine sample provides reliable PAH exposure ranking.

Effects of Polycyclic Aromatic Hydrocarbons on Lung Function in Children with Asthma: A Mediation Analysis

Studies investigating the association between urinary Polycyclic Aromatic Hydrocarbons (PAHs) and asthma in children provided inhomogeneous results. We aimed to use Mediation Analysis to discover whether a link between urinary PAHs and lung function exists and if it might be ascribed to a direct or a symptom-mediated (indirect) effect in children with asthma. This single-center prospective study was conducted in Palermo, Italy, between March and July 2017 and involved 50 children with persistent mild-moderate asthma, aged 6–11 years. At each time visit (day 0, 30, 60, and 90), physical examination, spirometry, and urine collection for detection of urinary cotinine and PAHs were performed. A symptom score was computed. The sum of individually calculated molar mass of nine PAH metabolites (ΣPAH), naphthalene metabolites (ΣPAHn) and phenanthrene metabolites (ΣPAHp) were calculated. Three children withdrew from the study due to technical problems (n = 1) and adverse events (n = 2). PAHs indirect effects on FEV1 (ΣPAH: −0.011, p = 0.04; ΣPAHn: −0.011, p = 0.04; ΣPAHp: −0.012, p < 0.001) and FVC (ΣPAH: −0.012, p = 0.02; ΣPAHn: −0.0126, p = 0.02; ΣPAHp: −0.013, p < 0.001) were statistically significant. In conclusion, PAHs exposures have significant indirect (symptom-mediated) effects on lung function, emphasizing the role of PAHs-induced respiratory morbidity in decreasing lung function in children with asthma.

Urinary monohydroxylated polycyclic aromatic hydrocarbons in the general population from 26 provincial capital cities in China: Levels, influencing factors, and health risks

Polycyclic aromatic hydrocarbons (PAHs) derived from the incomplete combustion of organic materials are associated with adverse health effects. However, little is known about PAH exposure levels and their influencing factors on a large scale in developing countries. In this study, urinary monohydroxylated metabolites of PAHs (OH-PAHs), including the metabolites of naphthalene, fluorene, phenanthrene, pyrene, chrysene, and benzo[a]pyrene, were measured in 1154 samples in the general population nationwide from 26 provincial capitals in China. Concentrations of OH-PAHs ranged from 1.39 to 228 μg/L. OH-Nap, metabolite of naphthalene, was the predominant compound, accounting for 65.1% of totals. People in eastern, southwest and northeast China, such as Shanghai, Kunming, Nanning, and Changchun, suffered more PAH exposure than other regions which might associate with sampling time, living habits of the subjects, and the imbalance of economic development and energy consumption across regions. Urinary OH-PAH concentrations were associated with body mass index, gender, and age, and smoking was the main correlating factor. Inhalation and diet might be the main exposure route of human exposure to PAHs, especially for smokers by inhalation. Hazard indices showed that no subject was exposed to PAHs with potential non-carcinogenic risk. Furthermore, the carcinogenic risk was the most significant health effects, with almost all subjects having carcinogenic risk values higher than the acceptable level of 10^-6. Naphthalene and phenanthrene were the main contributors. The results also suggested a possible relationship between PAH exposure and lung cancer in the Chinese population. This first nationwide study on human internal exposure to PAHs provides a large body of scientific information for governmental decision-making about associated human health and the prevention of human exposure to PAHs.

Nanomaterials for Remediation of Environmental Pollutants

Today, environmental contamination is a big concern for both developing and developed countries. The primary sources of contamination of land, water, and air are extensive industrialization and intense agricultural activities. Various traditional methods are available for the treatment of different pollutants in the environment, but all have some limitations. Due to this, an alternative method is required which is effective and less toxic and provides better outcomes. Nanomaterials have attracted a lot of interest in terms of environmental remediation. Because of their huge surface area and related high reactivity, nanomaterials perform better in environmental clean-up than other conventional approaches. They can be modified for specific uses to provide novel features. Due to the large surface-area-to-volume ratio and the presence of a larger number of reactive sites, nanoscale materials can be extremely reactive. These characteristics allow for higher interaction with contaminants, leading to a quick reduction of contaminant concentration. In the present review, an overview of different nanomaterials that are potential in the remediation of environmental pollutants has been discussed.

Evaluation of Carcinogenic Polyaromatic Hydrocarbon Levels in Airborne Particulates Associated with Long-Term Exposure throughout the COVID-19 Pandemic in Makkah, Saudi Arabia

BACKGROUND

The effect of polyaromatic hydrocarbons (PAHs) on human health differs depending on the duration and exposure path.

OBJECTIVE

This study aimed to examine the effects of PAHs on the human health risks associated with long-term exposure both before and throughout the COVID-19 pandemic.

METHODOLOGY

PM10 sampling for 24 h was conducted at six sampling sites (Al-Haram, Aziziyah, Al Nuzhah, Muzdalifah, Arafat, and Al Awali). On-site measurements were conducted from March 2020 to February 2021. PAHs were analyzed using Perkin Elmer GC/MS, which was adjusted with standard reagents for identifying 16 PAH mixtures.

RESULTS

The 24 h average PM10 concentration showed considerable inconsistencies, exceeding the WHO standards used for median exposure (25.0 µgm-3). The PAH intensities fluctuated from 7.67 to 34.7 ng/m3 in a suburban area, near a rush-hour traffic road, and from 6.34 to 37.4 ng/m3 close to business and light manufacturing areas. The highest carcinogenic compound levels were found in the Al-Azizia, Al Muzdalifah, and Al Nuzah areas because of the high traffic density, and the lowest concentrations were found in the Al-Haram and Arafat areas throughout the year, as a result of the COVID-19 pandemic health precautions that were undertaken by the government of Saudi Arabia involving border entry limits and limitations of the Umrah and Hajj seasons.

CONCLUSION

This study period is considered extraordinary as the Saudi Arabian government has undertaken successful preventive measures that have had a great effect both on the spread of the pandemic and in reducing air pollution in Makkah. More studies are required to examine PAHs' carcinogenic effects after the pandemic measures are eased across Makkah.

Characterization and health risk assessment of particulate bound polycyclic aromatic hydrocarbons (PAHs) in indoor and outdoor atmosphere of Central East India

The selected 16 high-priority polycyclic aromatic hydrocarbons (PAHs) were characterized in PM_2.5 in the indoor and outdoor air samples collected at the urban slum and rural sites in the Central East India. At the urban slum site, the indoor and outdoor concentrations of PAHs were 466.03± 11.94 ng/m³ and 321.71± 34.87 ng/m³, respectively. At the rural location, the indoor and outdoor concentrations were 294.85± 20.53 ng/m³ and 241.74± 29.04 ng/m³, respectively. Three-four and five-ring PAHs were found to be dominant in both urban slum and rural sites. Diagnostic ratio (DR) analysis and principal component analysis (PCA) conclude that diesel exhaust, gasoline, biomass, and coal combustion were the significant sources of 16 PAHs in indoor and outdoor environments, the urban slum and rural sites. Lifetime average daily dose (LADD) and incremental lifetime cancer risk (ILCR) values were calculated for health risk assessment for 6-year-old children and 24-year-old adults. The ELCR values in the urban slum site and the rural location were calculated 43.24 × 10^-6 and 28.3 × 10^-6. The ELCR values were observed between the acceptable limit 10^-6-10^-4 given by regulatory agency USEPA United States Environmental Protection Agency (1989).

Distribution, sources and exposure risk of polycyclic aromatic hydrocarbons in soils, and indoor and outdoor dust from Port Harcourt city, Nigeria

In this study, we evaluated the concentrations, composition, sources, and potential risks of polycyclic aromatic hydrocarbons (PAHs) in soils, and indoor and outdoor dust from Port Harcourt city in Nigeria. Gas chromatography-mass spectrometry (GC-MS) was used for the detection and quantification of PAH species in the samples. The concentrations of the US EPA 16 PAHs plus 2-methyl-naphthalene (∑17 PAHs) in soils, and indoor and outdoor dust from Port Harcourt city ranged from 240 to 38 400, 276 to 9130 and 44 to 13 200 μg kg^-1 (dry weight, d.w.) respectively. The PAH concentrations in these matrices followed the sequence: soil > indoor dust > outdoor dust. The composition of PAHs in soils and dust (indoor and outdoor) showed remarkable differences with prominence of 3- and 5-ring PAHs. The estimated carcinogenic risk to the residents arising from exposure to these concentrations of PAHs in soils, and indoor and outdoor dust from Port Harcourt was above the acceptable target cancer risk value of 10^-6. We concluded that these sites require clean-up, remedial actions and implementation of stringent pollution control measures with the intention of reducing the undesirable impacts of PAHs on both the ecosystem and humans.

Indoor/outdoor relationships, signatures, sources, and carcinogenic risk assessment of polycyclic aromatic hydrocarbons-enriched PM2.5 in an emerging port of northern China

Humans spend most of their time in indoor environments, thus a thorough understanding of indoor and outdoor PM_2.5-bound polycyclic aromatic hydrocarbons (PAHs) origins for accurate assessment of health risks is required. In the present study, 84 pairs of PM_2.5 samples from indoor (laboratory) and outdoor (campus) locations were collected from April to December 2018 in Caofeidian, China. The annual median concentration of PM_2.5 outdoors was 90.80 µg/m³, 9.08 times higher than the annual standard of WHO guideline (10 µg/m³). Indoor PM_2.5 annual median concentration (41.80 µg/m³) was also higher than the annual standard of ASHRAE guideline (15 µg/m³). The annual median concentrations of ∑₁₈PAHs indoors (44.23 ng/m³) and outdoors (189.6 ng/m³) were highest in winter and descended in the order of autumn > spring > summer. Contrary to summer and autumn, indoor/outdoor concentration ratios were less than 1 in spring and winter, indicating that the contribution of outdoor particle infiltration was more significant than that of indoor sources. The positive matrix factorization model suggested that indoor PAHs came from three sources: vehicle emissions (43%), biomass burning (37%), industry emissions, and coal combustion (20%). Outdoor PAHs came from four sources: petroleum volatilization (39%), vehicle emissions (30%), coal combustion (18%), and biomass burning (13%). The incremental lifetime cancer risk values of indoor and outdoor PAHs in winter exceeded the acceptable level (10^-6), and the carcinogenic risk of adults was higher than that of children and teenagers. These results indicated that simultaneous monitoring of indoor and outdoor PAHs is recommended for accurate assessment of health risk, and the analysis in the current work should be helpful to formulate policies to reduce PAHs emissions.

Source characterization and health risks of BTEX in indoor/outdoor air during winters at a terai precinct of North India

BTEX are the consistently found air contaminants in indoor and outdoor environments. In order to investigate the exposure levels of BTEX, the indoor and outdoor air was analyzed during winter season at homes located at four selected sites of Gorakhpur, Uttar Pradesh, India, which comprised residential, roadside, industrial and agricultural areas. BTEX were sampled with a low-flow pump (SKC model 220). Samples were extracted with CS₂ and the aromatic fraction was subjected to GC-FID. Mean indoor concentration of BTEX was highest at the agricultural (70.9 µg m^-3) followed by industrial (30.0 µg m^-3), roadside (17.5 µg m^-3) and residential site (11.8 µg m^-3). At outdoor locations, the mean BTEX levels were highest at the roadside (22.0 µg m^-3) followed by industrial (18.7 µg m^-3), agricultural (11.0 µg m^-3) and residential site (9.1 µg m^-3). The I/O ratios were greater than 1 at all the sites except roadside site, where I/O ratios for toluene, ethylbenzene and xylene were less than unity. Poor correlation between indoor and outdoor levels at each site further indicated the dominance of indoor sources. Factor analysis followed by one-way analysis of variance depicts that the presence of BTEX compounds at all the sites indicate a mixture of vehicular and combustion activities. For benzene, the ILTCR values exceeded the safe levels, whereas ethylbenzene was nearby to the recommended level 1 × 10^-6. The HQ values were above unity for agricultural (indoors) and industrial (outdoors) as an exception to all the other sites which indicted the value below unity.

Health damage to housewives by contaminants emitted from coal combustion in the Chinese countryside: focusing on day-to-day cooking

PURPOSE

The study aimed to estimate the health damage and find out the main exposure pathways of housewives posed by polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs) from coal combustion in rural areas of China.

METHODS

We obtained the concentrations of 16 PAHs and 8 HMs from published literatures and the Monte Carlo simulation was used to process and analysis the data. Sensitivity analysis was also applied to clear parameter uncertainty and the health damage of housewives was quantitatively evaluated by loss of life expectancy.

RESULTS

Housewives' carcinogenic risks from PAHs exposure were in descending order of inhalation > ingestion > dermal contact, while exposed to HMs were ingestion > dermal contact > inhalation. The carcinogenic risks from PAHs primarily originated from benzo[a]pyrene (BaP), dibenz[ah]anthracene (DahA) and benzo[b]fluorathene (BbF). For HMs, arsenic posed the highest carcinogenic risk to housewives, with a contribution of 92.98%. In addition, the life expectancy loss of housewives exposed to PAHs was 469.04 min from inhalation and 51.82 min for HMs from ingestion.

CONCLUSION

Through a comprehensive assessment of the health risks in housewives exposed to emissions from coal combustion, we can gain insight into the hazards from PAHs and HMs in housewives, and take measures to reduce their exposure risks.

Development of sol-gel phenyl/methyl/poly (dimethylsiloxane) sorbent coating for fabric phase sorptive extraction and its application in monitoring human exposure to selected polycyclic aromatic hydrocarbons using high performance liquid chromatography-fluorescence detection

Following the convenient, yet very powerful pathway to create designer extraction sorbent using sol-gel chemistry, a novel sol-gel phenyl/methyl/poly(dimethylsiloxane) sorbent coating was created on polyester fabric substrate for fabric phase sorptive extraction (FPSE) and was subsequently applied to monitor human exposure to selected polycyclic aromatic hydrocarbons (PAHs) including pyrene, chrysene, and benzo[a]pyrene in plasma samples obtained from tobacco smoker volunteers using high performance liquid chromatography-fluorescence detector (HPLC-FLD). A rapid FPSE-HPLC-FLD method was developed that adequately resolved the PAHs chromatographically, after their successful extraction from human plasma using fabric phase absorption extraction (FPSE) and subsequently analysed in the liquid chromatographic system by means of an analytical column (InterSustain C-18 column 150 × 4.6 mm, 5 μm) using acetonitrile (ACN) and water as mobile phases in gradient elution mode. With the optimized conditions, the retention times were found to be 6.168, 7.214, and 10.404 min for pyrene, chrysene, and benzo[a]pyrene, respectively. The total chromatographic runtime was limited to 12.5 min. The method, validated through the calculation of all the analytical parameters according to the International Guidelines, was applied to the analysis of real samples collected from informed volunteers. The proposed approach which included the use of sol-gel phenyl/methyl/poly(dimethylsiloxane) immobilized on hydrophobic polyester substrate and C18 stationary phase used in HPLC, has shown a high potential as a rapid tool for future clinical, forensic and toxicological applications, also in the light of the LOD and LOQ values comparable to those normally obtainable with more sophisticated, and expensive instruments that often require highly trained personnel. The results reported here further consolidate the application of FPSE in the analysis of biological samples for both diagnostic and analytical-clinical purposes.

Indoor Exposure to Selected Air Pollutants in the Home Environment: A Systematic Review

(1) Background: There is increasing awareness that the quality of the indoor environment affects our health and well-being. Indoor air quality (IAQ) in particular has an impact on multiple health outcomes, including respiratory and cardiovascular illness, allergic symptoms, cancers, and premature mortality. (2) Methods: We carried out a global systematic literature review on indoor exposure to selected air pollutants associated with adverse health effects, and related household characteristics, seasonal influences and occupancy patterns. We screened records from six bibliographic databases: ABI/INFORM, Environment Abstracts, Pollution Abstracts, PubMed, ProQuest Biological and Health Professional, and Scopus. (3) Results: Information on indoor exposure levels and determinants, emission sources, and associated health effects was extracted from 141 studies from 29 countries. The most-studied pollutants were particulate matter (PM_2.5 and PM₁₀); nitrogen dioxide (NO₂); volatile organic compounds (VOCs) including benzene, toluene, xylenes and formaldehyde; and polycyclic aromatic hydrocarbons (PAHs) including naphthalene. Identified indoor PM_2.5 sources include smoking, cooking, heating, use of incense, candles, and insecticides, while cleaning, housework, presence of pets and movement of people were the main sources of coarse particles. Outdoor air is a major PM_2.5 source in rooms with natural ventilation in roadside households. Major sources of NO₂ indoors are unvented gas heaters and cookers. Predictors of indoor NO₂ are ventilation, season, and outdoor NO₂ levels. VOCs are emitted from a wide range of indoor and outdoor sources, including smoking, solvent use, renovations, and household products. Formaldehyde levels are higher in newer houses and in the presence of new furniture, while PAH levels are higher in smoking households. High indoor particulate matter, NO₂ and VOC levels were typically associated with respiratory symptoms, particularly asthma symptoms in children. (4) Conclusions: Household characteristics and occupant activities play a large role in indoor exposure, particularly cigarette smoking for PM_2.5, gas appliances for NO₂, and household products for VOCs and PAHs. Home location near high-traffic-density roads, redecoration, and small house size contribute to high indoor air pollution. In most studies, air exchange rates are negatively associated with indoor air pollution. These findings can inform interventions aiming to improve IAQ in residential properties in a variety of settings.

Health risks associated with the polycyclic aromatic hydrocarbons in indoor dust collected from houses in Kuwait

Polycyclic aromatic hydrocarbons (PAHs) are a byproduct of combustion processes. They are common pollutants in oil-producing countries because fossil fuel processing generates PAHs that associate with dust. Airborne particles containing PAHs are transported into houses during dust storms, which are common in the arid oil-producing countries, and consequently the children and adults in the household are exposed to PAHs in indoor house dust. The goal of this study was to present a systematic survey of PAHs in indoor house dust in Kuwait. The PAHs concentrations and composition of indoor house dust was determined, along with their probable source and the potential carcinogenic risks. Total PAHs concentrations (ƩPAH) were, on average (±standard deviation) 1112 ± 347 μg/kg and ranged from 450 to 2242 μg/kg. Heavier congeners (4-6 ring PAHs) represented 61% of the ƩPAH. Petroleum combustion and traffic emissions were the major source of PAHs, based on the isomeric ratios of PAHs in indoor house dust. The incremental lifetime cancer risks (ILCRs) of exposure to PAHs in indoor house dust was 2.23 × 10^-3 (95% CI: 1.99 × 10^-3 - 2.48 × 10^-3) for children and 2.15 × 10^-3 (95% CI: 1.94 × 10^-3 - 2.37 × 10^-3) for adults, exceeding the US EPA safe limit of 1 × 10^-6. Therefore, exposure to PAHs present in indoor house dust increases the cancer risk for children and adults in Kuwait.

Spatial distribution patterns and human exposure risks of polycyclic aromatic hydrocarbons, organochlorine pesticides and polychlorinated biphenyls in Nepal using tree bark as a passive air sampler

Nepal is abutted between the populated Indo-Gangetic Plain (IGP) and Himalayan mountains. Currently, knowledge on the country-wide distribution and cancer risks of atmospheric organic toxicants in Nepal remains limited. In this study, the concentrations, sources, and distributions of polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs), and polychlorinated biphenyls (PCBs), along with their cancer risks, were investigated in Nepal by using tree bark as a passive air sampler. After transferring by a bark/air partitioning model, the averaged concentrations of ∑PAHs, ∑DDTs, ∑HCHs, HCB, ∑Endo and ∑PCBs in the atmosphere of Nepal were 3.71 × 10⁴ pg/m³, 1.10 × 10³ pg/m³, 2.92 × 10² pg/m³, 4.38 × 10² pg/m³, 4.66 pg/m³ and 65.8 pg/m³, respectively. Source diagnosis suggested that biomass burning is the major source for PAHs, while local application and long-range transport jointly contribute to the high levels of DDT and HCH in the air. The ILCR (incremental lifetime cancer risk) value was used to assess the risks of various chemicals. Adults have a higher risk than other age groups; the major exposure pathway for risk is by inhalation; and PAHs and HCHs are the dominant chemical classes that lead to risk. It was also found that, in certain hotspots in south Nepal, the carcinogenic risks caused by DDT and HCH were particularly high (>1 × 10^-4). Given that illegal and disordered use of legacy POPs in south Nepal and the IGP region is common, our results highlight an urgent need for voluntary regulation of the ongoing use of pesticides.

Carcinogenic risk from exposure to PM2.5 bound polycyclic aromatic hydrocarbons in rural settings

In the study, first-time personal exposure level of polycyclic aromatic hydrocarbons (PAHs) was measured during cooking hours in participants of three different types of kitchen both in the particulate and gaseous phase using traditional and improved cookstoves. Along with that, indoor particulate matter (PM) concentration was also estimated during the cooking hours to examine the impact of intervention in different kitchens. The results of the study clearly revealed that the kitchen characteristics and type of cookstove technology have a significant impact on PM_2.5, PM₁ and PAHs concentration. Cookstoves intervention has resulted in maximum reduction of PM₁ i.e. 75% in an enclosed kitchen followed by semi-enclosed and open kitchen having 71% and 52%, respectively. In addition, correlation analysis of PM_2.5 and PM₁ with PAHs showed a strong association (r² = 0.9), showing the affinity of PAHs to bind to fine range of particles. Health risk assessment was also carried out to assess the PM daily dose and carcinogenic and non-carcinogenic risk due to inhalation of PAHs. The study confirmed the personal concentration of PAHs compounds was significantly high (p < 0.05) during use of traditional cookstove compared to improved cookstove among all the three kitchens. Furthermore, to measure the toxicity levels, PAHs concentrations have been converted to benzo[a]pyrene equivalence for calculating cancer and non-cancer effects using toxicity equivalency factors. The overall lifetime carcinogenic risk was the highest 2.5E-03, 6.4E-04 among women who prepared meals in the enclosed kitchen compared to 8.4E-04, 1.3E-04 in semi-enclosed and 2.2E-04, 4.6E-05 in the open kitchen during use of traditional and improved cookstoves, respectively, which exceeded the US EPA standard i.e. 1 × 10^-6. The study underlined the importance of personal monitoring for exposure, and risks-based studies along with the time-activity of user to measure the actual inhalation risk for the participants. These findings indicated that women are exposed to hazardous smoke in the indoor kitchen and are at greater risk of developing cancer, especially in rural areas.

Particle-associated polycyclic aromatic hydrocarbons in a representative urban location (indoor-outdoor) from South Europe: Assessment of potential sources and cancer risk to humans

PM₁₀ -bound polycyclic aromatic hydrocarbons (PAHs) levels were monitored at urban locations (outdoor/indoor) within the city of Madrid between May 2017 and April 2018. Fourteen PAH congeners were measured, potential emission sources were identified as were potential carcinogenic risks. The ΣPAHs averaged 0.577 and 0.186 ng/m³ in outdoor and indoor air, with a high linear correlation per individual mean PAH and month. The largest contributors to the ΣPAHs were the high-molecular-weight PAHs. Principal component analysis-multiple linear regression results showed that emissions from diesel and vehicular processes explained 27% and 23% of the total variance of outdoor and indoor air, while combustion processes accounted for 30% and 25% in ambient and indoor air, respectively. During the cold season, biomass burning plus coal and wood combustion were additional sources of outdoor emissions. The heavy-, medium- and light-molecular-weight PAH originating from outdoor sources accounted for 72%, 80%, and ~60% of the indoor levels of the three respective PAH groups. Average BaP concentration was 0.029 and 0.016 ng/m³ in outdoor and indoor air, respectively. Estimated BaPeq concentration averaged 0.072, 0.035, and 0.027 ng/m³ for outdoor, indoor, and indoor-generated individual PAH concentrations, respectively. The estimated carcinogenic risk falls within the range of acceptable risk targeted by the US-EPA.

Baseline investigation on plasticizers, bisphenol A, polycyclic aromatic hydrocarbons and heavy metals in the surface soil of the informal electronic waste recycling workshops and nearby open dumpsites in Indian metropolitan cities

Electronic waste (e-waste) has emerged as a global environmental problem because of its massive production volume and un-structured management policy. Since the rate of e-waste accumulation is startling and the combinatorial effects of toxicants are complex, we have investigated six phthalic acid esters (PAEs), bis (2-ethylhexyl) adipate (DEHA)), bisphenol A (BPA), sixteen polycyclic aromatic hydrocarbons (PAHs) and eight heavy metals (HMs) in the surface soil of e-waste recycling workshops and nearby open dumpsites in four metropolitan cities of India viz., New Delhi (north), Kolkata (east), Mumbai (west) and Chennai (south). Average concentration of ∑₁₆PAHs (1259 ng/g), ∑₆PAEs (396 ng/g), BPA (140 ng/g) and ∑₈HM (1288 mg/kg) in the informal e-waste recycling sites were higher than ∑₁₆PAHs (1029 ng/g), ∑₆PAEs (93 ng/g), BPA (121 ng/g) and ∑₈HM (675 mg/kg) in dumpsites. Almost 50-90% of BPA, bis (2-ethylhexyl) phthalate (DEHP), ∑_7carcPAHs and copper (Cu) were from e-waste sites predominantly from metal recovery sites (EWR). Extensive combustion of e-waste particularly in the EWR sites at New Moore market and Pudupet in Chennai and Wire Lane, Kurla of Mumbai can explain the segregation of diethyl phthalate (DEP), benzyl butyl phthalate (BBP) and carcinogenic PAHs in the first principal component (PC-1). Copper and lead along with highly abundant plasticizers like DEHP, dibutyl phthalate (DBP) and BPA were loaded in PC-2. Combined impact of burning the plastic cables in e-waste and acid leaching process especially at Mandoli in New Delhi might have driven this result. Loading of chrysene, DEHA and low molecular weight (LMW) PAHs mostly in dumpsite soil might have resulted from incomplete combustion of dumped e-waste. Copper was found to exhibit the highest pollution estimated by geo-accumulation index (Igeo). Maximum estimated carcinogenic risk for adults via dermal contact was due to copper, followed by chromium, lead and nickel.

Monitoring of indoor polycyclic aromatic hydrocarbons using spider webs

Fifteen polycyclic aromatic hydrocarbons (PAHs) were measured in the spider webs prepared in the laboratory and exposed to indoor air pollution in a defined period of time. We have selected homes differing in location (rural area vs. city), type of room (living room, kitchen, basement), inhabitants' habits (smoking cigarettes vs. non-smoking) and type of heating/cooking devices used (natural gas, liquefied gas, coal- and wood-fuelled heating). Webs from two species, from Agelenidae and Pholcidae families, were prepared and used for monitoring of PAHs. PAHs were characterised based on concentration, profile distribution, source apportionment by cluster analysis and diagnostic ratios. The concentrations of sum of 15 PAHs (μg g^-1 dry weight) varied from 1.7 (bedroom in detached house in rural area) to 67.9 μg g^-1 (room with heavy smokers in detached house in the city), and were dominated by 3-ring (6.89-57.1%) and 2-ring compounds (5.05-48.3%). The result of cluster analysis (CA) suggested two distinct groups of PAHs. The dominant PAH source was found to be mixed petrogenic and pyrogenic consisting of a mixture of cooking, smoking, heating and neighbouring traffic activities.

Role of glutathione S-transferases in detoxification of a polycyclic aromatic hydrocarbon, methylcholanthrene

Glutathione S-transferases (GSTs), the versatile phase II biotransformation enzymes, metabolize and detoxify a wide variety of toxic chemical compounds like carcinogens, chemotherapeutic drugs, environmental pollutants and oxidative stress products. GSTs are currently of great interest in drug discovery, nanotechnology and biotechnology because of their involvement in many major cellular processes. GSTs, which are either homo or hetero dimeric proteins mediate catalytic binding between glutathione (GSH) and an array of either endogenous or exogenous toxic compounds to form a highly soluble detoxified complex which is then eliminated. Polycyclic aromatic hydrocarbons (PAHs) which are composed of two or more benzene rings bonded as linear, cluster or angular arrangements are used as intermediaries in pharmaceuticals, agricultural products, photographic products, thermosetting plastics, lubricating materials and other chemical products. Foods those cooked at high temperatures by grilling, roasting, frying and smoking are the main sources for the persistent bio-accumulation of PAHs in food chain. The carcinogenic, mutagenic and immunosuppressive effects of PAHs are well established. A well-known polycyclic aromatic hydrocarbon, methylcholanthrene is a potential carcinogenic, neurotoxic, mutagenic and tumour causing agent that is used as an experimental carcinogen in biological research. Methylcholanthrene converts into reactive metabolites when it enters living cells and those reactive metabolites oxidize DNA, RNA, proteins and lipids and form DNA and protein adducts as well. GSTs play major role in the detoxification of reactive metabolites of methylcholanthrene by mediating catalytic binding with GSH to form a highly soluble detoxified complex which is then eliminated. This review summarizes the role of GSTs in the detoxification of a polycyclic aromatic hydrocarbon, methylcholanthrene.

Levels and risk assessment of hydrocarbons and organochlorines in aerosols from a North African coastal city (Bizerte, Tunisia)

The aim of this study was to assess, for the first time, the concentrations, sources, dry deposition and human health risks of polycyclic aromatic hydrocarbons (PAHs), aliphatic hydrocarbons (AHs), polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in total suspended particle (TSP) samples collected in Bizerte city, Tunisia (North Africa), during one year (March 2015-January 2016). Concentrations of PAHs, AHs, PCBs and OCPs ranged 0.5-17.8 ng m^-3, 6.7-126.5 ng m^-3, 0.3-11 pg m^-3 and 0.2-3.6 pg m^-3, respectively, with higher levels of all contaminants measured in winter. A combined analysis revealed AHs originating from both biogenic and petrogenic sources, while diesel vehicle emissions were identified as dominant sources for PAHs. PCB potential sources included electronic, iron, cement, lubricant factories located within or outside Bizerte city. The dominant OCP congeners were p,p'-DDT and p,p'-DDE, reflecting a current or past use in agriculture. Health risk assessment showed that the lifetime excess cancer risk from exposure to airborne BaP was negligible in Bizerte, except in winter, where a potential risk to the local population may occur.

The burden of disease attributable to ambient PM2.5-bound PAHs exposure in Nagpur, India

Exposure to PM_2.5-bound polycyclic aromatic hydrocarbons (PAHs) can elicit several types of cancer and non-cancer effects. Previous studies reported substantial burdens of PAH-induced lung cancer, but the burdens of other cancer types and non-cancer effects remain unknown. Thus, we estimate the cancer and non-cancer burden of disease, in disability-adjusted life years (DALYs), attributable to ambient PM_2.5-bound PAHs exposure in Nagpur district, India, using risk-based approach. We measured thirteen PAHs in airborne PM_2.5 sampled from nine sites covering urban, peri-urban and rural areas, from February 2013 to June 2014. We converted PAHs concentrations to benzo[a]pyrene equivalence (B[a]P_eq) for cancer and non-cancer effects using relative potency factors, and relative toxicity factors derived from quantitative structure-activity relationships, respectively. We calculated time-weighted exposure to B[a]P_eq, averaged over 30 years, and adjusted for early-life susceptibility to cancer. We estimated the DALYs/year using B[a]P_eq exposure levels, published toxicity data, and severity of the diseases from Global Burden of Disease 2016 database. The annual average concentration of total PM_2.5-bound PAHs was 458 ± 246 ng/m³ and resulted in 49,500 DALYs/year (0.011 DALYs/person/year). The PAH-related DALYs followed this order: developmental (mostly cardiovascular) impairments (55.1%) > cancer (26.5%) or lung cancer (23.1%) > immunological impairments (18.0%) > reproductive abnormalities (0.4%).

Polycyclic aromatic hydrocarbons in soils and lichen from the western Tibetan Plateau: Concentration profiles, distribution and its influencing factors

The Tibetan Plateau (TP) is a huge area and rarely affected by human activity, and is regarded as one of the most remote regions on the earth. Many studies about the long-range atmospheric transport (LRAT) of semi-volatile organic compounds (SVOCs) were conducted in southern and central TP. However, there are very limited studies focused on PAHs in the western TP and the concentrations profiles, distribution and its controlling factors in this area remains unclear. Thus, to explore this knowledge gap, 37 surface soil samples and 23 lichen samples were collected and analyzed for PAHs. The total concentration of 16 US EPA's priority PAHs (∑₁₆PAHs) in western TP ranges 14.4-59.5ng/g and 38.0-133ng/g dry weight (dw) with a mean value of 30.8 and 84.6ng/g dw in soil and lichen, respectively, which is lower than the concentrations in most remote areas worldwide. In the western TP, low molecular weight PAHs (2-3 rings) are dominant (occupied 77.4% and 87.9% on average in soil and lichen, respectively), implying a significant contribution of LRAT in this area. The significant linear correlations (R² = 0.372-0.627, p < 0.05) between longitude and soil concentration suggest a strong impact of the westerly wind on the distribution of PAHs in soil. In addition, the concentration ratio of lichen/soil (L/S) was found to linearly increase with the increasing log K_OA of individual PAH, suggesting lichen has a strong ability in filtering more lipophilic airborne pollutants in western TP.

Elucidating the urban levels, sources and health risks of polycyclic aromatic hydrocarbons (PAHs) in Pakistan: Implications for changing energy demand

Due to the severe fuel crisis in terms of natural gas, a paradigm shift in fuel combustion (diesel, gasoline, and biomass) may increase the atmospheric emissions and associated health risks in Pakistan. Present study was aimed to investigate the concentration of fugitive PAHs in the environment (outdoor and indoor settings), associated probabilistic health risk assessment in the exposed population, and possible linkage between fuel consumption patterns and PAHs emissions in twin cities (Rawalpindi and Islamabad) of Pakistan. Results showed that the mean PAHs concentrations (air: 2390pgm^-3; dust: 167ngg^-1) in the indoor environment were higher than that of the outdoor environment (air: 2132pgm^-3; dust: 90.0ngg^-1). Further, the source apportionment PCA-MLR receptor model identified diesel and gasoline combustion as the primary PAHs sources in the urban and sub-urban settings. Estimated life cancer risk (LCR) potential via inhalation to indoor PAHs was higher with a probability of 2.0 cases per 10,000 inhabitants as compared to outdoor exposure. Incremental lifetime cancer risk (ILCR) model from exposure to dust bound PAHs showed risk in the order of ingestion>dermal>inhalation for various exposure pathways. Likewise, estimated daily intake (EDI) model reflects that PAHs in surface dust enter into the human body mainly through the respiratory system because EDI for breathing was reported higher than that of oral intake. Therefore, adoption of sustainable fuels is recommended to meet the energy requirements and to reduce PAHs emissions and related health risks in the twin cities of Pakistan.

Association Between Placental Polycyclic Aromatic Hydrocarbons (PAHS), Oxidative Stress, and Preterm Delivery: A Case-Control Study

Polycyclic aromatic hydrocarbons are known to disturb the antioxidant defense system, which may indirectly contribute to induction of early pregnancy in women. Therefore, the present investigation was designed to offer preliminary information about exposure to PAHs by estimating their placental levels and its association with oxidative stress as well as with preterm birth. Placenta tissue samples were drawn after delivery from 84 healthy pregnant women, recruited at a local nursing home of Agra, India, and levels of PAHs were quantified by gas chromatograph equipped with flame ionization detector. To evaluate redox status biomarkers, malondialdehyde (MDA) and glutathione (GSH) were determined in placenta tissue. Significantly elevated levels of benzo(a)pyrene and MDA while decreasing trend of GSH was found in women with preterm delivery group (study) than women with a full-term delivery group (control). Results demonstrated higher, but statistically insignificant (p > 0.05), levels of naphthalene, anthracene, fluorene, pyrene, benzo(b)fluoranthene, benzo(k)fluoranthene, indeno[1,2,3-cd]pyrene, dibenzo(ah)anthracene, and benzo(ghi)perylene in the study group than the control group. However, higher and lower molecular weight PAHs showed significant correlation for the depletion trend of GSH sights upon an example of oxidative stress mechanism. Because of limited statistical power and absence of controlled confounders, this study does not provide an ample involvement of PAHs with preterm delivery but increased MDA and decreased GSH in cases than controls gives the possible contribution of PAHs to early delivery.

Appraisement, source apportionment and health risk of polycyclic aromatic hydrocarbons (PAHs) in vehicle-wash wastewater, Pakistan

Vehicle-wash wastewater (VWW) contains elevated concentrations of different petrochemicals including polycyclic aromatic hydrocarbons (PAHs), a carcinogenic group of organic compounds. This study investigates the discharge of PAHs present in the untreated wastewater of vehicle-wash stations (VWS) located in district Peshawar, Pakistan. The data obtained was being novel with the detection of 16 USEPA PAHs (both individuals and total) and compared with earlier studies and international standards. The ∑16PAHs in wastewater from light vehicle-wash stations (LVWS) and heavy vehicle-wash stations (HVWS) ranged from 245-429μg/l and 957-1582μg/l, respectively. A significant difference (p<0.01) was observed in PAHs discharged from LVWS and HVWS. The projected ∑16PAHs discharge from both HVWS (92% of total generated PAHs) and LVWS (8%) was about 5109.9 g per annum. According to PAH diagnostic ratios, PAHs were both petrogenic (chrysene/benz(a)anthracene, low molecular weight/high molecular weight) and pyrogenic (phenanthrene/anthracene, fluoranthene/pyrene, fluoranthene/fluoranthene+pyrene) in origin. The highest toxic equivalent quotient (TEQ) value was shown by benzo(a)pyrene (21.6μg/l) followed by dibenz(ah)anthracene (9.81μg/l) in wastewater from HVWS. However, in LVWS the case was reversed with highest value (7.54μg/l) for dibenz(ah)anthracene followed by benzo(a)pyrene (3.54μg/l). The lowest TEQ value was indicated for phenanthrene (0.007μg/l) in wastewater of LVWS, while pyrene showed the lowest value (0.007μg/l) in wastewater of HVWS. The results indicated that VWS contribute significant amount of PAHs each year, which is of great concern regarding water quality, ecological and human health risk. This is the first systematic and comprehensive research related with generation of PAHs load per day, week, month and annum from VWS, their source apportionment and health effects in Pakistan.

Organic and inorganic speciation of particulate matter formed during different combustion phases in an improved cookstove

Residential solid fuel combustion in cookstoves has established health impacts including bladder and lung cancers, cataracts, low birth weight, and pneumonia. The chemical composition of particulate matter (PM) from 4 commonly-used solid fuels (coal, dung, ambient/dry applewood, and oakwood pellets), emitted from a gasifier cookstove, as well as propane, were examined. Temporal changes between the different cookstove burn-phases were also explored. Normalized concentrations of non-refractory PM₁, total organics, chloride, ammonium, nitrate, sulfate, and 41 particle-phase polycyclic aromatic hydrocarbons (PAHs) were measured using a High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) and a Thermal desorption Aerosol Gas chromatograph (TAG), respectively. Coal demonstrated the highest fraction of organic matter in its particulate emission composition (98%), followed by dung (94%). Coal and dung also demonstrated the highest numbers and concentrations of PAHs. While dry applewood emitted ten times lower organic matter compared to ambient applewood, a higher fraction of these organics was composed of PAHs, especially the more toxic ones such as benzo(a)pyrene (9.63ng/L versus 0.04ng/L), and benzo(b)fluoranthene (31.32ng/L versus 0.19ng/L). Data from the AMS demonstrated no clear trends for any of the combustion fuels over the different combustion phases unlike the previously reported trends observed for the physical characteristics. Of the solid fuels, pellets demonstrated the lowest emissions. Emissions from propane were below the quantification limit of the instruments. This work highlights the benefits of incorporating additional metrics into the cookstove evaluation process, thus enriching the existing PM data inventory.

Exposure profiles, seasonal variation and health risk assessment of BTEX in indoor air of homes at different microenvironments of a terai province of northern India

BTEX are known for their ability to deteriorate human health. A monitoring study was conducted at Gorakhpur, for a span of one year. BTEX were sampled by drawing air through activated charcoal tubes, using a low flow SKC model 220 pump. Samples were extracted with CS₂ followed by subjecting the aromatic fraction to GC-FID. The mean concentration of BTEX was highest at agricultural (54.3 μg m^-3) followed by industrial (18.2 μg m^-3), roadside (12.3 μg m^-3) and residential site (6.1 μg m^-3). Toluene levels were higher than benzene at all the sites except agricultural site, where benzene concentration exceeded toluene. Seasonal variation showed highest BTEX concentration during winters (32.56 μg m^-3) followed by monsoon (19.90 μg m^-3) and summers (14.44 μg m^-3). At each site, BTEX levels increased with decrease in temperature. Benzene and toluene levels were plotted against indoor temperature, which revealed a significant linear correlation (p < 0.001) for each plot. BTEX concentrations were compared between different sites using Student's t and Mann Whitney U tests. Value of integrated lifetime cancer risk (ILTCR) was higher than 10^-6 for benzene at all the sites, while for ethylbenzene, it was only higher at agricultural site. Cumulative hazard index (HI) was lower than 1.0 at all the sites.

Fine particulate-bound polycyclic aromatic hydrocarbons in vehicles in Rome, Italy

Urban commuters are exposed to elevated levels of air pollutants, especially in heavily polluted areas and traffic congested roads. In order to assess the contribution of commuting to citizens' exposure, measurements of fine particulate (PM_2.5) and polycyclic aromatic hydrocarbons (PAHs) were carried out in cars, busses, and metro trains, within the LIFE+ EXPAH Project. Monitoring campaigns were performed in Rome, Italy, from April 2011 to August 2012. Inside the busses, the concentration of total PAHs ranged from 2.7 to 6.6 ng/m³ during the winter and from 0.34 to 1.51 ng/m³ in the summer. In cars, internal concentrations were in the range 2.2-7.3 and 0.46-0.82 ng/m³, respectively, in the 2-year time. Analogous differences between seasons were observed examining the benzo[a]pyrene-equivalent carcinogenicity. In the metro trains, total PAHs ranged from 1.19 to 2.35 ng/m³ and PM_2.5 ranged from 17 to 31 μg/m³. The PM_2.5 concentration in all transport modes ranged from 10 to 160 μg/m³ during the cold season and 15-48 μg/m³ during the warm time. The average inside-to-outside ratio (R _I/O) was found to exceed 1.0 for PM_2.5 only in busses, probably due to dust re-suspension caused by crowding and passenger activity. The molecular PAH signature suggests that vehicle emissions and biomass combustion were the major sources of commuters' exposure to these toxicants in Rome. According to linear regression analysis, the PAH concentrations inside the vehicles were linked to those detected outside. Statistically significant differences (p < 0.05) were found between the in-vehicle locations and the urban pollution network stations, with higher PAH values detected, on the average, in these latter.

A Review on the Abundance, Distribution and Eco-Biological Risks of PAHs in the Key Environmental Matrices of South Asia

Polycyclic aromatic hydrocarbons (PAHs) are consistently posing high risks to human/biota in developing countries of South Asia where domestic areas are exposed to biomass burning and commercial/industrial activities. This review article summarized the available data on PAHs occurrence, distribution, potential sources and their possible risks in the key environmental matrices (i.e., Air, Soil/Sediments, Water) from South Asian Region (SAR). Available literature reviewed suggested that PAHs concentration levels were strongly influenced by the monsoonal rainfall system in the region and it has been supported by many studies that higher concentrations were measured during the winter season as compared to summer. Biomass burning (household and brick kilns activities), open burning of solid wastes and industrial and vehicular emissions were categorized as major sources of PAHs in the region. Regional comparison revealed that the contamination levels of PAHs in the water bodies and soil/sediments in SAR remained higher relatively to the reports from other regions of the world. Our findings highlight that there is still a general lack of reliable data, inventories and research studies addressing PAHs related issues in the context of environmental and human health in SAR. There is therefore a critical need to improve the current knowledge base, which should build upon the research experience from other regions which have experienced similar situations in the past. Further research into these issues in South Asia is considered vital to help inform future policies/control strategies as already successfully implemented in other countries.

Polycyclic aromatic hydrocarbons in primary school environments: Levels and potential risks

Although polycyclic aromatic hydrocarbons (PAHs) are priority air pollutants that strongly affect human health, information concerning the indoor exposures is still limited. This study characterized PAH levels in primary schools and evaluated risk for the respective students (aged 8-10years) in comparison with school personnel. During January-April 2014, eighteen particulate-bound (PM_2.5) PAHs (16 USEPA priority compounds, dibenzo[a,l]pyrene, benzo[j]fluoranthene) were collected (indoors and outdoors) at ten primary urban schools in Portugal. Total mean concentrations (Σ_PAHs) ranged 2.8-54ngm^-3 in indoor air, whereas corresponding outdoor levels were 7.1-48ngm^-3. Indoor/outdoor ratios of lighter congeners (2-3 aromatic rings) demonstrated a contribution from indoor origin while heavier PAHs (4-6 aromatic rings) originated mostly from infiltration of ambient air indoors; traffic (both from diesel and gasoline fuelled vehicles) was the predominant source of indoor PAHs. Total cancer risk of 8-10years old children exceeded (up to 22 times) USEPA recommended guideline of 10^-6, and 7-87 times WHO health-based threshold of 10^-5. Risk due to indoor exposure in schools was 2-10 times higher than outdoors, mainly because of the higher amount of time that students spent indoors.

Distribution, Fate, Inhalation Exposure and Lung Cancer Risk of Atmospheric Polycyclic Aromatic Hydrocarbons in Some Asian Countries

A large-scale monitoring program, the Asia Soil and Air Monitoring Program (Asia-SAMP), was conducted in five Asian countries, including China, Japan, South Korea, Vietnam, and India. Air samples were collected using passive air samplers with polyurethane foam disks over four consecutive 3-month periods from September 2012 to August 2013 to measure the seasonal concentrations of 47 polycyclic aromatic hydrocarbons (PAHs), including 21 parent and 26 alkylated PAHs, at 176 sites (11 background, 83 rural, and 82 urban). The annual concentrations of total 47 PAHs (∑47PAHs) at all sites ranged from 6.29 to 688 ng/m(3) with median of 82.2 ng/m(3). Air concentrations of PAHs in China, Vietnam, and India were greater than those in Japan and South Korea. As expected, the air concentrations (ng/m(3)) were highest at urban sites (143 ± 117) followed by rural (126 ± 147) and background sites (22.4 ± 11.4). Significant positive correlations were found between PAH concentrations and atmosphere aerosol optical depth. The average benzo(a)pyrene equivalent concentration (BaPeq) was 5.61 ng/m(3). It was estimated that the annual BaPeq concentrations at 78.8% of the sampling sites exceeded the WHO guideline level. The mean population attributable fraction (PAF) for lung cancer due to inhalation exposure to outdoor PAHs was on the order 8.8‰ (0.056-52‰) for China, 0.38‰ (0.007-3.2‰) for Japan, 0.85‰ (0.042-4.5‰) for South Korea, 7.5‰ (0.26-27‰) for Vietnam, and 3.2‰ (0.047-20‰) for India. We estimated a number of lifetime excess lung cancer cases caused by exposure to PAHs, which the concentrations ranging from 27.8 to 2200, 1.36 to 108, 2.45 to 194, 21.8 to 1730, and 9.10 to 720 per million people for China, Japan, South Korea, Vietnam, and India, respectively. Overall, the lung cancer risk in China and Vietnam were higher than that in Japan, South Korea, and India.

Distribution patterns, infiltration and health risk assessment of PM2.5-bound PAHs in indoor and outdoor air in cold zone

In this study we investigated the distribution patterns, infiltration and health risk assessment of PM2.5-bound PAHs in indoor and outdoor air done in Harbin city, northeastern China. Simultaneous indoor and outdoor sampling was done to collect 264 PM2.5 samples from four sites during winter, summer, and spring. Infiltration of PAHs into indoors was estimated using Retene, Benzo [ghi]perylene and Chrysene as reference compounds, where the latter compound was suggested to be a good estimator and subsequently used for further calculation of infiltration factors (IFs). Modeling with positive matrix factorization (PMF5) and estimation of diagnostic isomeric ratios were applied for identifying sources, where coal combustion, crop residues burning and traffic being the major contributors, particularly during winter. Linear discriminant analysis (LDA) has been utilized to show the distribution patterns of individual PAH congeners. LDA showed that, the greatest seasonal variability was attributed to high molecular weight compounds (HMW PAHs). Potential health risk of PAHs exposure was assessed through relative potency factor approach (RPF). The levels of the sum of 16 US EPA priority PAHs during colder months were very high, with average values of 377 ± 228 ng m(-)(3) and 102 ± 75.8 ng m(-)(3), for the outdoors and indoors, respectively. The outdoor levels reported to be 19 times higher than the outdoor concentrations during warmer months (summer + spring), while the indoor concentrations were suggested to be 9 times and 10 times higher than that for indoor summer (average 11.73 ± 4 ng m(-3)) and indoor spring (9.5 ± 3.3 ng m(-3)). During nighttime, outdoor PAHs revealed wider range of values compared to datytime which was likely due to outdoor temperature, a weather parameter with the strongest negative influence on ∑16PAHs compared to low impact of relative humidity and wind speed.

Characterization of particulate-bound PAHs in rural households using different types of domestic energy in Henan Province, China

The concentrations and composition of sixteen PAHs adsorbed to respirable particulate matter (PM10≤10 μm) and inhalable particulate matter (PM2.5≤2.5 μm) were determined during autumn and winter in rural households of Henan Province, China, which used four types of domestic energy [crop residues, coal, liquid petroleum gas (LPG) and electricity] for cooking and heating. The present results show that there were significantly (p<0.05) seasonal variations of particulate-bound PAHs in the rural households. The daily mean concentrations of particulate-bound PAHs in the kitchens, sitting rooms and outdoors were apparently higher in winter than those in autumn, except those in the kitchens using coal. The present study also shows that there were obvious variations of particulate-bound PAHs among the four types of domestic energy used in the rural households. The households using LPG for cooking can, at least in some circumstances, have higher concentrations of PAHs in the kitchens than using crop residues or electricity. In addition, using coal in the sitting rooms seemed to result in apparently higher concentrations of particulate-bound PAHs than using the other three types of domestic energy during winter. The most severe contamination occurred in the kitchens using LPG in winter, where the daily mean concentrations of PM2.5-bound PAHs were up to 762.5±931.2 ng m(-3), indicating that there was serious health risk of inhalation exposure to PAHs in the rural households of Henan Province. Rural residents' exposure to PM2.5-bound PAHs in kitchens would be roughly reduced by 69.8% and 85.5% via replacing coal or crop residues with electricity in autumn. The pilot research would provide important supplementary information to the indoor air pollution studies in rural area.

Photocatalytic degradation of polycyclic aromatic hydrocarbon benzo[a]pyrene by iron oxides and identification of degradation products

Photocatalytic decay profiles of polycyclic aromatic hydrocarbon (PAH) benzo[a]pyrene (B[a]P) have been investigated on various synthesized iron oxides and on soil surfaces under a set of diverse conditions. Samples were analysed using the developed HPLC procedure. Results of the present study demonstrate fastest photodisintegration of B[a]P on goethite followed by haematite, magnetite, akaganeite and maghemite, respectively. The effect of soil pH, irradiation wavelength and iron oxide and oxalic acid dose on the degradation of B[a]P was evaluated. The studies revealed enhancement in photodegradation in the presence of oxalic acid due to the occurrence of fenton like reaction. The results showed faster B[a]P degradation under short wavelength UV radiation. Rate constants in acidic, neutral and alkaline soils under optimum dissipation conditions were 1.11×10(-2), 7.69×10(-3) and 9.97×10(-3) h(-1), respectively. The study indicates that iron oxides along with oxalic acid are effective photocatalyst for the remediation of benzo[a]pyrene contaminated soil surfaces. The degradation products of B[a]P in the soils of different pH in presence of goethite were identified and degradation pathways proposed. Peaks due to toxic metabolites such as diones, diols and epoxides disappear after 120 h in all the three soils.

Spatiotemporal analysis and human exposure assessment on polycyclic aromatic hydrocarbons in indoor air, settled house dust, and diet: A review

This review summarizes the published literature on the presence of polycyclic aromatic hydrocarbons (PAH) in indoor air, settled house dust, and food, and highlights geographical and temporal trends in indoor PAH contamination. In both indoor air and dust, ΣPAH concentrations in North America have decreased over the past 30 years with a halving time of 6.7±1.9years in indoor air and 5.0±2.3 years in indoor dust. In contrast, indoor PAH concentrations in Asia have remained steady. Concentrations of ΣPAH in indoor air are significantly (p<0.01) higher in Asia than North America. In studies recording both vapor and particulate phases, the global average concentration in indoor air of ΣPAH excluding naphthalene is between 7 and 14,300 ng/m(3). Over a similar period, the average ΣPAH concentration in house dust ranges between 127 to 115,817ng/g. Indoor/outdoor ratios of atmospheric concentrations of ΣPAH have declined globally with a half-life of 6.3±2.3 years. While indoor/outdoor ratios for benzo[a]pyrene toxicity equivalents (BaPeq) declined in North America with a half-life of 12.2±3.2 years, no significant decline was observed when data from all regions were considered. Comparison of the global database, revealed that I/O ratios for ΣPAH (average=4.3±1.3), exceeded significantly those of BaPeq (average=1.7±0.4) in the same samples. The significant decline in global I/O ratios suggests that indoor sources of PAH have been controlled more effectively than outdoor sources. Moreover, the significantly higher I/O ratios for ΣPAH compared to BaPeq, imply that indoor sources of PAH emit proportionally more of the less carcinogenic PAH than outdoor sources. Dietary exposure to PAH ranges from 137 to 55,000 ng/day. Definitive spatiotemporal trends in dietary exposure were precluded due to relatively small number of relevant studies. However, although reported in only one study, PAH concentrations in Chinese diets exceeded those in diet from other parts of the world, a pattern consistent with the spatial trends observed for concentrations of PAH in indoor air. Evaluation of human exposure to ΣPAH via inhalation, dust and diet ingestion, suggests that while intake via diet and inhalation exceeds that via dust ingestion; all three pathways contribute and merit continued assessment.

Effects of urbanization on gaseous and particulate polycyclic aromatic hydrocarbons and polychlorinated biphenyls in a coastal city, China: levels, sources, and health risks

Gas/particle distributions of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) were measured in Xiamen from May 2009 to March 2010 to evaluate the impacts of urbanization on the fate of persistent organic pollutants (POPs) in the atmospheric environment. In a newly developing area (NDA), the concentrations of 16 PAHs (gas + particle) were significantly higher than that a historically urbanized area (HUA) (p value <0.05), while the trend of 28 PCBs was reversed. Diagnostic ratios and principle component analysis (PCA) implied that atmospheric PAHs in the NDA were mainly derived from petrogenic combustion, including mixed sources of vehicle emissions, biomass burning and oil combustion, while pyrogenic combustion (e.g., traffic and coal combustion) was considered the major source of PAHs in the HUA. Atmospheric PCBs in both HUA and NDA were dominated by TriCBs and PeCBs related to the use of commercial mixtures (Aroclors 1242 and 1254). Based on the toxicological equivalent factor (TEF) approach, total benzo[a]pyrene equivalent values in the HUA and NDA were 1.12 and 2.02 ng m(-3), respectively, exceeding the standard threshold values (1.0 ng m(-3)) of China and WHO. Average daily intake of dioxin-like compounds was 0.2 pg kg(-1) day(-1) in the HUA, which are below the WHO tolerable daily intake level. The results showed that the contribution to the toxic equivalency (TEQ) was dominated by PCB169, PCB105, and PCB81.

Concentrations, particle-size distributions, and indoor/outdoor differences of polycyclic aromatic hydrocarbons (PAHs) in a middle school classroom in Xi'an, China

Polycyclic aromatic hydrocarbons (PAHs) attached to particulate matter can affect respiratory health, especially the health of children, but information on the air quality in schools is generally lacking. This study investigated the PAH concentrations in a naturally ventilated classroom in Xi'an, China, from 16 to 31 May 2012. Particulate PAH concentrations were measured for samples collected on five-stage cascade impactors deployed inside the classroom and outside. PM2.5-bound PAH concentrations were 53.2 ng m(-3) indoors and 72.9 ng m(-3) outdoors. PAHs attached to very fine particles (VFPs) accounted for ~70% of the total PAHs. The PAH concentrations indoors were affected by the students' activities, cleaning, and smoking, while outdoors, the main sources were motor vehicle emissions and contaminated road dust. Particle-bound PAHs infiltrated the classroom through open windows, but the activities of the students and staff were also associated with an increase of PAHs attached to particles larger than 1.0 µm, most likely through resuspension. Cycles in the sources led to PAH concentrations 2-3 times higher on weekdays compared to weekends, both indoors and outdoors. PAH toxicity risks inside the classroom were substantially lower than those outdoors, and the highest risks were associated with VFPs.

Characterizations, relationship, and potential sources of outdoor and indoor particulate matter bound polycyclic aromatic hydrocarbons (PAHs) in a community of Tianjin, Northern China

Polycyclic aromatic hydrocarbons (PAHs) are among the most toxic air pollutants in China. However, because there are unsubstantial data on indoor and outdoor particulate PAHs, efforts in assessing inhalation exposure and cancer risk to PAHs are limited in China. This study measured 12 individual PAHs in indoor and outdoor environments at 36 homes during the non-heating period and heating period in 2009. Indoor PAH concentrations were comparable with outdoor environments in the non-heating period, but were lower in the heating period. The average indoor/outdoor ratios in both sampling periods were lower than 1, while the ratios in the non-heating period were higher than those in the heating period. Correlation analysis and coefficient of divergence also verified the difference between indoor and outdoor PAHs, which could be caused by high ventilation in the non-heating period. To support this conclusion, linear and robust regressions were used to estimate the infiltration factor to compare outdoor PAHs to indoor PAHs. The calculated infiltration factors obtained by the two models were similar in the non-heating period but varied greatly in the heating period, which may have been caused by the influence of ventilation. Potential sources were distinguished using a diagnostic ratio and a mixture of coal combustion and traffic emission, which are major sources of PAHs.