The mutagenic hazards of settled house dust: a review

Contamination level, spatial distribution, and sources of potentially toxic elements in indoor settled household dusts in Tehran, Iran

Tehran, the capital city of Iran, has been facing air pollution for several decades due to rapid urbanization, population growth, improper vehicle use, and the low quality of fuels. In this study, 31 indoor dust samples were collected passively from residential and commercial buildings located in the central and densely populated districts of the city. These samples were analyzed after preparation to measure the concentration of elements (As, Be, Cd, Co, Cr, Cu, Fe, Hg, Mn, Mo, Ni, Pb, Se, Sr, V, Zn). Statistical data analyses were employed to compare their relationship across various uses, variations, and for source identification. Geochemical indices of contamination factor (CF) and pollution load index (PLI) were utilized to evaluate the degree of contamination. The mean concentrations of Zn, Cu, and Pb (938, 206, and 176 µg g-1, respectively) are 6, 5, and 3 times higher than their mean values in worldwide urban soils. Additionally, Cd, Mo, and Ni showed concentrations about 1.5 times higher, while As, Co, Cr, Mn, and Sr fell within the range of reference soils. Be, V, and Sb displayed remarkably lower mean values. Building use did not significantly influence element levels in indoor deposited dust except for Pb and Zn. A comparison of indoor concentrations with previously published data for outdoor dusts revealed higher enrichments of Mo, Cu, Pb, and Ni, while As, Cd, and Zn showed lower enrichments in street dust samples. The order of CF values indicated Hg > Zn > Cd > Pb > Cu > As > Ni > Cr > Co > V. For Hg, Zn, Pb, Cd, and Cu, all or almost all samples exhibited very high contamination. PLI values were consistently higher than 1, indicating contamination in all samples. Multivariate statistical analysis and Tehran's specific geological location suggested that mafic-intermediate volcanic rocks are primary sources for Cr, Cu, Fe, and Ni (PC1). As, Pb, and V (PC2) were attributed to fossil fuel combustion in vehicles and residential buildings. Pb is a legacy metal remaining from the use of leaded gasoline, which was phased out in the 1990s. Zn (PC3) is derived from vehicle tires.

Evaluating the Contamination by Indoor Dust in Dubai

Nowadays, people spend most of their time indoors. Despite constantly cleaning these spaces, dust apparition cannot be avoided. Since dust can contain chemical elements that negatively impact people's health, we propose the analysis of the metals from the indoor dust component collected in different locations in Dubai, UAE. Multivariate statistics (correlation matrix, clustering) and quality indicators (QI)-Igeo, PI, EF, PLI, Nemerow-were used to assess the contamination level with different metals in the dust. We proposed two new QIs (CPI and AQI) and compared the results with those provided by the most used indices-PLI and Nemerow. It is shown that high concentrations of some elements (Ca in this case) can significantly increase the values of the Nemerow index, CPI, and AQI. In contrast, the existence of low concentrations leads to the decrement of the PLI.

Estimate of the maximum amount of dust adhering to skin and the upper limit of dust-skin adherence factor for young adults: An example from Changchun, China

Contaminants present in dust adhering to the skin can pose a significant risk to human health through dermal absorption and hand-to-mouth contact. The adhesion capacity of dust differs significantly from that of soil due to its physicochemical properties. Therefore, applying the raw soil exposure parameters to estimate the health risks associated with dermal exposure to dust may lead to erroneous conclusions. In this study, we quantified the maximum amount of dust that adhered to the skin (MADmax) and the upper limit of dust-skin adherence factor (DSAFmax) in 26 adults using element markers as a proxy for dust. The volunteers were exposed to dust and rinse water samples were collected from their hands, forearms, lower legs, and feet. We analyzed both the raw dust samples and the rinse water samples for 11 element markers, including Be, V, Cr, Mn, Co, Ni, Cu, Zn, Se, Ba, and Pb. The results showed that the MADmax of indoor dust and outdoor dust increased by 0.08-0.62 mg and 0.33-0.56 mg following a 1 cm2 increase in skin surface area, respectively. Based on best dust element markers, the body part-weighted dust-skin adherences (WDSAFmaxs) of indoor dust and outdoor dust were 0.35 and 0.64 mg/cm2, respectively. A smaller particle size and higher moisture content resulted in a larger DSAFmax. Only when indoor dust concentrations exceed 24.2 mg/m3 or outdoor dust concentrations exceed 44.3 mg/m3, can the WDSAFmax be applied directly in the health risk assessment of dermal exposure to dust. The method from this study can be re-applied in different regions, and the adherence data can help to improve future studies on the health effects of dermal exposure to dust.

Polyaromatic hydrocarbon thin film layers on glass, dust, and polyurethane foam surfaces

An investigation was conducted into the dynamic behavior of two polyaromatic hydrocarbon (PAH) semi-volatile organic compound (SVOC) naphthalene (NAP) and benzo [ghi]perylene (BghiP) in air and on various surfaces including glass, dust, and polyurethane foam (PUF) to understand their interaction with different media. A confocal fluorescence microscope and an infrared microscope were employed to detect and monitor the concentration-, time-, and temperature-dependent changes of the aromatic NAP and BghiP species on the surfaces. Infrared two-dimensional mapping of the vibrational characteristic peaks was used to track the two PAHs on the surfaces. Gas chromatography-mass spectrometry (GC-MS) was employed to measure the gaseous concentrations. The sorption of NAP and BghiP on the surfaces was estimated using Arizona desert sand fine (ISO 12103-1 A2) dust and organic contaminant household (SRM 2585) dust. The surface-to-air partition coefficients of NAP and BghiP were estimated on the different surfaces of glass, dust, and PUF. Molecular dynamic simulations were performed on dust surfaces based on the Hatcher model to understand the behavior of NAP and BghiP on dust surfaces. The Weschler-Nazaroff model was introduced to predictPAH film accumulation on the surfaces, providing a better understanding of PAH interaction with different environmental media. These findings could contribute to developing effective strategies to mitigate the adverse impact of PAHs on the environment and human health.

Pollution Characteristics, Source Apportionment, and Health Risk of Polycyclic Aromatic Hydrocarbons (PAHs) of Fine Street Dust during and after COVID-19 Lockdown in Bangladesh

The COVID-19 period has had a significant impact on both the global environment and daily living. The COVID-19 lockdown may provide an opportunity to enhance environmental quality. This study has evaluated the effect of the COVID-19 lockdown on the distribution of polycyclic aromatic hydrocarbons (PAHs) in the street dust (diameter < 20 µm) of different land use areas in Dhaka city, Bangladesh, using gas chromatography–mass spectrometry (GC–MS). The maximum (2114 ng g−1) concentration of ∑16 PAHs was found in the industrial area during without lockdown conditions and the minimum (932 ng g−1) concentration was found in the public facilities area during the complete lockdown. Meanwhile, due to the partial lockdown, a maximum of 30% of the ∑16 PAH concentration decreased from the situation of without lockdown in the industrial area. The highest result of 53% of the ∑16 PAH concentration decreased from the situation without lockdown to the complete lockdown in the commercial area. The 4-ring PAHs had the highest contribution, both during and after the lockdown conditions. PAH ratios, correlation, principal component analysis (PCA), and hierarchical clustering analysis (HCA) were applied in order to evaluate the possible sources. Two major origins of PAHs in the street dust were identified as petroleum and petrogenic sources, as well as biomass and coal combustion. Ingestion and dermal pathways were identified as the major exposure routes to PAHs in the dust. The total incremental lifetime cancer risk (ILCR) due to exposure for adults and children ranged from 8.38 × 10−8 to 1.16 × 10−7 and from 5.11 × 10−8 to 1.70 × 10−7, respectively. These values were lower than the baseline value of acceptable risk (10–6), indicating no potential carcinogenic risk. This study found that the COVID-19 lockdown reduced the distribution of PAHs in the different sites of Dhaka city, thus providing a unique opportunity for the remarkable improvement of degraded environmental resources.

Polycyclic Aromatic Hydrocarbons in Indoor Dust in Croatia: Levels, Sources, and Human Health Risks

Compounds that contribute to indoor pollution are regularly investigated due to the fact that people spend most of their time indoors. Worldwide investigations have shown that polycyclic aromatic hydrocarbons (PAHs) are present in indoor dust, but to the best of our knowledge, this paper reports for the first time the presence of PAHs in Croatian households. Eleven PAHs were analysed in house dust samples collected in the city of Zagreb and surroundings (N = 66). Their possible indoor sources and the associated health risks were assessed. Total mass fraction of detected PAHs ranged from 92.9 ng g^-1 to 1504.1 ng g^-1 (median 466.8 ng g^-1), whereby four-ring compounds, Flu and Pyr, contributed the most. DahA was the only compound that did not show statistically significantly positive correlation with other analysed PAHs, indicating that it originated from different sources. Based on diagnostic ratios and principal component analysis (PCA), mixed sources contributed to PAHs levels present in Croatian households. Although our results indicate that Croatian house dusts are weakly polluted with PAHs, total ILCR values calculated for children and adults revealed that people exposed to the highest mass fractions of PAHs measured in this area are at elevated cancer risk.

Population Health Risks Assessment from Air Pollution Exposure in an Industrialized Residential Area in Greece

Industrial activities nearby residential areas lead to poor local air quality. Therefore, short-term exposure to an aggravated environment and the subsequent health effects should be the subject of further research. The purpose of this study is to estimate the health risks resulting from such exposure in population groups living in an industrialized area. The risk estimation was performed using different approaches suggested in relative literature. Monitoring of the air quality in an industrial zone of Attica was carried out including 24-h measurements of PM2.5 and analysis of their chemical composition for Polycyclic Aromatic Hydrocarbons and heavy metals (Pb, Cd, As, Ni, Hg, Cu, Zn). Samples of Volatile Organic Compounds were also collected. Health effects on different population subgroups were estimated for the targeted pollutants through different mathematical approaches provided by the literature, taking into consideration different parameters (e.g., age, gender, exposure duration). Inhalation rate and body weight were important parameters to estimate the exposure dose of people, and they can vary greatly depending on the age, gender, and daily activity of the person under consideration. The results indicated that the risk for potential carcinogenic and non-carcinogenic effects varies depending on the applied methodology. In any case, the acceptable limits for cancer risk provided by the OEHHA, EPA, and WHO were not exceeded.

Toxic organic pollutants in Greek house dust: Implications for human exposure and health risk

Organic contaminants often documented in house dust include mainly chemicals released from construction materials and consumer products and compounds emitted from indoor combustion activities. The occurrence of major chemical classes of toxic organic pollutants, included polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs) and nitrated polycyclic aromatic hydrocarbons (NPAHs), was for the first time investigated in house dust in Greece. The mean concentrations of ∑₁₆PAHs, ∑₂₀PBDEs, ∑₇NPAHs and∑₁₅PCBs in house dust were 4650 ng g^-1, 564 ng g^-1, 7.52 ng g^-1, and 6.29 ng g^-1, respectively. Exposure to dust organic contaminants via ingestion, inhalation and dermal absorption was estimated for two age classes (adults and children) and carcinogenic and non-carcinogenic risks were assessed. The hazard index (HI) for adults and children for PBDEs, PCBs, PAHs and NPAHs in all samples was less than 1 suggesting a very low level of concern for all human age group due to exposure to those chemicals. Total carcinogenic risk via the three exposure pathways (ingestion, inhalation and dermal contact) was within the safe range of 10^-6 to 10^-4.

Source, Characterization of Indoor Dust PAHs and the Health Risk on Chinese Children

Polycyclic aromatic hydrocarbons (PAHs) in indoor dust are one of the common exposure sources for children worldwide. The aim of this study is to explore PAHs pollution status in indoor dust and estimate health risk on Chinese children with big data. Weighted average concentration was used to analyze source and characterization of PAHs in indoor dust based on peer-reviewed literature. According to specific inclusion criteria, 17 studies were included finally to analyze weighted average concentration. The national average concentration of Σ₁₆PAHs was approximately 25.696 µg/g. The highest concentration of Σ₁₆PAHs was in Shanxi (2111.667 µg/g), and the lowest was in Hong Kong (1.505 µg/g). The concentrations in Shanxi and Guangdong were higher than national level and the over standard rate was 18.18%. The concentrations of individual PAHs varied greatly across the country, and Flu in Shanxi was the highest (189.400 µg/g). The sources of PAHs varied in different regions and combustion processes played a leading role. PAHs exposure through ingestion and dermal contact was more carcinogenic than inhalation. The incremental lifetime cancer risk model indicated that children lived in Shanxi were found in the highest health risk coupled with the highest BaPE concentration (54.074 µg/g). Although PAHs concentrations of indoor dust showed a downward trend from 2005 to 2018, indoor environmental sanitation should be improved with multidisciplinary efforts. Health standard should be possibly established to minimize children exposure to PAHs in indoor dust in China.

The influence of demographic and lifestyle factors on urinary levels of PAH metabolites-empirical analyses of Cycle 2 (2009-2011) CHMS data

Polycyclic aromatic hydrocarbons (PAHs) are a group of compounds formed during the incomplete combustion of organic matter. Several are mutagenic carcinogens; the magnitude of exposure can be assessed by examining urinary levels of PAH metabolites. Data from biomonitoring studies that record urinary PAH metabolite levels, as well as demographic and lifestyle information, can be used to investigate relationships between PAH exposure and variables, such as smoking status, workplace smoking restrictions, age, sex, household income, home age, and occupation. This study analysed creatinine-adjusted urinary PAH metabolite concentrations and questionnaire data from ~1200 individuals aged 16 years and older surveyed in Cycle 2 of the Canadian Health Measures Survey (CHMS). Statistical analyses revealed that smoking status, age, and sex are associated with urinary concentrations of a pyrene metabolite (1-OHP), phenanthrene metabolites (ΣOH-Phen), fluorene metabolites (ΣOH-Flu) and naphthalene metabolites (ΣOH-Nap). More specifically, smoking status, age and sex can collectively account for 30, 24, 52, and 34% of the observed variations in 1-OHP, ΣOH-Phen, ΣOH-Flu and ΣOH-Nap metabolites, respectively (p < 0.001). Analyses of non-smokers revealed weak but significant effects of age, sex, home age, and occupation on urinary levels of selected PAH metabolites (i.e., <7% of observed variation, p < 0.05). The unexplained variation in PAH metabolite levels is most likely related to diet, which was not examined. Although the results revealed significant relationships between urinary PAH metabolite levels and several lifestyle and/or demographic variables, robust examinations of selected effects (e.g., sex, home age, occupation) will require datasets that are balanced with respect to the other highlighted variables. The results can be used to identify remedial measures to reduce exposure and concomitant risk, and/or design follow-up studies to test hypotheses regarding the causes of exposure differences empirically related to sex, age, home age, and occupation.

Polycyclic aromatic compounds in particulate matter and indoor dust at preschools in Stockholm, Sweden: Occurrence, sources and genotoxic potential in vitro

Children spend a significant amount of their day in preschool; thus, environmental quality at preschools may have an impact on children's health. In the present study, we analyzed polycyclic aromatic compounds (PACs), including PAHs, alkylated PAHs and oxygenated PAHs (OPAHs), in indoor and outdoor air particulate matter (PM₁₀) and indoor dust at preschools in Stockholm, Sweden. There were significant correlations between PAC levels in outdoor and indoor PM₁₀, with in general higher PAC levels outdoors. Fluoranthene and pyrene were detected at highest levels in all sample types, although phenanthrene and methylated phenanthrene derivatives also were found at high levels in indoor dust. In addition, the highly carcinogenic PAHs 7H-benzo[c]fluorene, 7,12-dimethylbenz[a]anthracene, benz[j]aceanthrylene, and dibenzo[a,l]pyrene were detected in some samples. Benzanthrone was the most prevalent OPAH in PM₁₀ samples and 9,10-anthraquinone in indoor dust. Based on diagnostic ratios and Positive Matrix Factorization we identified vehicle emission and biomass burning as important PAC sources for all samples analyzed. However, poor correlation between PAC levels in indoor PM₁₀ and indoor dust suggested additional sources for the latter. Measuring activation of DNA damage signaling in human cells exposed to organic extracts of the samples indicated substantial genotoxic potential of outdoor PM₁₀ and indoor dust. Determination of benzo[a]pyrene equivalents demonstrated that the highly potent PAHs benz[j]aceanthrylene and dibenz[a,h]anthracene contributed more than 20% to the total carcinogenic potency of the samples. We conclude that PAC levels at Stockholm preschools are relatively low but that outdoor air quality may impact on the indoor environment.

Heavy metals in indoor dust: Spatial distribution, influencing factors, and potential health risks

Given the large proportion of time that people spend indoors, the potential health risks posed by heavy metals in the indoor environment deserve greater attention. A global-scale assessment of heavy metal contamination in indoor dust was conducted in this study based on >127 articles published between 1985 and 2019. The pollution levels, spatio-temporal variations, sources, bioaccessibilities, influencing factors, and health risks of heavy metals associated with indoor dust were analyzed. Children's blood lead levels (BLLs) were also estimated using the integrated exposure uptake biokinetic model. The results indicated that the median concentrations of Cu and Zn in 71.9% and 71.0% of the study sites surpassed the corresponding permissible limits, 100 and 300 mg/kg, respectively; thus, their control should be given priority. Heavy metal concentrations in indoor dust from different areas of the world varied greatly, which was closely associated with the type of local human activities, such as mining, melting, e-waste recycling and Pb-related industries. The bioaccessibilities of some key elements, e.g., Pb, Cd, Cu, and Zn, in household dust were high. The levels of heavy metals in indoor dust were mainly affected by a combination of outdoor and indoor sources and related critical factors, and future studies should focus on quantifying the contributions of different sources. Based on the health risk assessment, dust Pb exposure is a major health concern in e-waste recycling areas, which warrants greater attention. 49.8%, 36.8% and 14.4% of study sites showed BLLs exceeding 35 μg/L (threshold limit in Germany), 50 μg/L (threshold limit in the USA), or 100 μg/L (threshold limit in China), respectively. Finally, Pb exposure from indoor dust represents a major contributor to children's blood Pb poisoning in many developing countries. This study details the overall heavy metal contamination status of indoor dust and provides insights for policymakers with respect to pollution prevention measures.

Contamination and Potential Risk Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) and Heavy Metals in House Settled Dust Collected from Residences of Young Children

House settled dust (HSD) contains various hazardous materials, including polycyclic aromatic hydrocarbons (PAHs) and metals. Exposure to toxicants contained in HSD is of paramount concern especially in the case of young children, due to their particular behavioral characteristics. In this context, extracts of sieved vacuum cleaner dust from 20 residences with young children were examined for the presence of PAHs and trace metals, in Athens, Greece. The results indicated that PAHs and metals were ubiquitous in the studied residences. The calculated enrichment factors (EF) of trace metals indicated that Cu, Se, Zn, Hg, Cd, and Pb were mainly of anthropogenic. According to the PCA analysis, the main sources of household dust were: smoking inside the houses, combustion processes, resuspension of soil dust, and vehicle traffic. In general, the cancer risk due to PAHs exposure was found lower than the threshold value. The ingestion of house dust was the most important route of exposure to metals. The dose of almost all elements for the children was found 1–2 orders of magnitude lower than the corresponding reference values. Both the carcinogenic and noncarcinogenic risks of exposure were within the safety limits.

Organic pollutants in indoor dust from Ecuadorian Amazonia areas affected by oil extractivism

Fifty-five household dust samples collected within six settlements surrounding oil production complexes along the Ecuadorian Amazonia were analysed to evaluate the occurrence and distribution of polycyclic aromatic hydrocarbons (PAHs), phthalates, alkylphenols (APs), bisphenol A (BPA), nicotine, organophosphorus flame retardants (OPFRs), polychlorinated biphenyls (PCBs), legacy organochlorine pesticides (OCs) and organophosphorus pesticides. Studied areas are mainly affected by gas flares emissions and oil spilling coming from extractivist operations and pesticides used in agriculture. Median ΣPAHs values ranged from 739 to 1182 ng g^-1 and up to 52% of the PAH dust concentrations were associated to petrogenic activities from crude oil extraction, according to diagnostic ratios. ΣPAHs and toxic equivalents based on benzo[a]pyrene concentration (ΣTEQ_BaP, ng g^-1) suggested similar toxicities among the different areas. Individual lifetime cancer risk (ILCR_dust) was calculated for ingestion and dermal contact exposure routes and a non-acceptable total carcinogenic risk of up to 10^-4 (one case per ten thousand people) was found for newborns from 0 to 3 years-old in Pimampiro area. Plasticisers and OPFRs were present in dust at maximum median concentrations of 332,507 ng g^-1 (DEHP), 5,249 ng g^-1 (DBP), 1,885 ng g^-1 (BPA), 871 ng g^-1 (TBOEP) and 122 ng g^-1 (TEHP). Some dust samples from Ecuadorian houses had high maximum levels of legacy and modern pesticides such as chlorpyrifos (up to 44,176 ng g^-1), 4,4'-DDT (12,958 ng g^-1), malathion (34,748 ng g^-1) and α+β-endosulfan (10,660 ng g^-1) attributed to inappropriate use and storage of the pesticides. Finally, nicotine was seldom detected (36 ng g^-1). The sources and risks of these compounds are discussed based on the activities carried out in the study areas and attending to an additional non-cancer risk assessment which showed high hazard quotients (HQ) and hazard indexes (HI) for DEHP, DBP, 4,4'-DDT, malathion, chlorpyrifos, naphthalene and benzo[a]pyrene in newborns and children up to 16 years-old.

In vitro genomic damage induced by urban fine particulate matter on human lymphocytes

Urban air pollution represents a global problem, since everyday many mutagenic and carcinogens compounds are emitted into the atmosphere, with consequent adverse health effects on humans and biota. Specifically, particulate matter air pollution was associated with increased risks in human mortality and morbidity. In this paper, we analyse the genomic effects on human lymphocytes of different concentrations of annual Turin PM2.5 extract by an in vitro micronuclei assay. Samplings were collected from an urban meteorological-chemical station positioned in Turin (Italy), one of the most polluted cities in Europe. PM2.5 sampled on filters was used for organic extraction in monthly pools and successively aggregated to produce a mixture representative for a full year PM2.5 collection. Lymphocytes were exposed to four concentrations of PM2.5: 5, 10, 15 and 20 μg/mL and micronuclei, nucleoplasmic bridges and nuclear buds were scored. With respect to controls, PM2.5 significantly increased the frequencies of all analysed biomarkers at all tested concentrations, whereas the CBPI index was significantly reduced only at the concentration of 20 μg/mL. Such in vitro effects can both to stimulate local authorities to adopt efficient measures for air pollution mitigation and to improve human monitoring to detect early precancer lesions.

Distribution, sources and health risk of PAHs in urban air-conditioning dust from Hefei, East China

In recent decades, indoor air quality (IAQ) has become one of the most important human health issues. The potential properties and potential health hazards of polycyclic aromatic hydrocarbons (PAHs) are associated with their long-term residues, bioaccumulation and semivolatility, and they can also be transferred through a variety of media, such as the atmosphere, water and soil. Dust particles from indoor and outdoor emission sources adhere to A-C filters and can represent air quality to a certain extent. However, few studies have focused on PAHs in A-C filter dust in Hefei, China. In this study, 16 PAHs were selected, dust samples were collected from A-C filters from three different functional districts, and GC-MS analysis of the samples was performed. The concentration of the ∑16PAHs ranged from 7.34 to 326.84 μg g^-1, 5.07-15.34 μg g^-1, 4.09-47.26 μg g^-1 and 0.97-13.38 μg g^-1 in dust samples from the Administrative District (AD), Industrial District (ID), Commercial District (CD) and Outdoors (OD), respectively. The total PAH concentration in A-C dust was much higher than that in dust deposited outdoors in the urban area. The percentage of 5-6 ring PAHs accounted for more than 70% of the ∑16PAHs, which shows that the PAHs in A-C dust mainly come from pyrolysis rather than a diagenetic source. Principal component analysis (PCA) and diagnostic ratios were used in a source analysis, and the results indicated that the main PAHs emission sources in the different functional districts were coal, wood and biomass combustion. The incremental lifetime cancer risk (ILCR) values indicated a medium to high potential carcinogenic risk for adults and children exposed to dust with PAHs. Particularly, skin contact and ingestion of carcinogenic PAHs from dust are the major exposure pathways and present an exposure risk that is four to five orders of magnitude higher than the risk of inhalation.

Characteristics and health risk assessment of polycyclic aromatic hydrocarbons associated with dust in household evaporative coolers

This study reports a characterization of indoor polycyclic aromatic hydrocarbons (PAHs) associated with dust (dust-PAHs) in household evaporative coolers and their associated health effects. Extensive analysis showed that the indoor dust-PAHs stemmed mostly from pyrogenic sources (vehicular emissions) with mean total concentrations limited between 131 and 429 ng g^-1. The distribution pattern of PAHs based on number of rings exhibited the following order of decreasing relative abundance: 4 > 3 > 5 > 6 > 2 rings. Results indicate that the mutagenicity of dust-PAHs exceeded their carcinogenicity, but that the potential carcinogenic effects are still significant. The mean lifetime cancer risk for different age groups for three pathways based on Model 2 (dermal (1.39 × 10^-1 to 1.91 × 10^-2), ingestion (2.13 × 10^-3 to 8.08 × 10^-3) and inhalation (1.62 × 10^-7 to 4.06 × 10^-7)) was 7.4-146 times higher than values predicted by Model 1 (dermal (5.13 × 10^-5 to 3.03 × 10^-3), ingestion (9.34 × 10^-5 to 1.31 × 10^-3) and inhalation (7.13 × 10^-20 to 1.68 × 10^-20)). Hence, exposure to dust-PAHs in household evaporative coolers lead to high risk, especially for children (less than 11 years) (HQ = 2.71 × 10^-20 to 54.8 and LTCRs = 7.13 × 10^-20 to 1.39 × 10^-1). Strategies should be considered to eliminate such pollutants to protect people, especially children, from the non-carcinogenic and carcinogenic effects by changing household evaporative coolers with other cooling systems.

Household Dust: Loadings and PM10-Bound Plasticizers and Polycyclic Aromatic Hydrocarbons

Residential dust is recognized as a major source of environmental contaminants, including polycyclic aromatic hydrocarbons (PAHs) and plasticizers, such as phthalic acid esters (PAEs). A sampling campaign was carried out to characterize the dust fraction of particulate matter with an aerodynamic diameter smaller than 10 µm (PM10), using an in situ resuspension chamber in three rooms (kitchen, living room, and bedroom) of four Spanish houses. Two samples per room were collected with, at least, a one-week interval. The PM10 samples were analyzed for their carbonaceous content by a thermo-optical technique and, after solvent extraction, for 20 PAHs, 8 PAEs and one non-phthalate plasticizer (DEHA) by gas chromatography-mass spectrometry. In general, higher dust loads were observed for parquet flooring as compared with tile. The highest dust loads were obtained for rugs. Total carbon accounted for 9.3 to 51 wt% of the PM10 mass. Plasticizer mass fractions varied from 5 µg g−1 to 17 mg g−1 PM10, whereas lower contributions were registered for PAHs (0.98 to 116 µg g−1). The plasticizer and PAH daily intakes for children and adults via dust ingestion were estimated to be three to four orders of magnitude higher than those via inhalation and dermal contact. The thoracic fraction of household dust was estimated to contribute to an excess of 7.2 to 14 per million people new cancer cases, which exceeds the acceptable risk of one per million.

Nasal lavages as a tool for monitoring exposure to organic pollutants

Exposure to air and dust pollutants can cause several adverse effects on human health. This study proposes the use of nasal lavages as a non-invasive sampling technique to determine in a direct way pollutant intake through inhalation. We evaluate the occurrence of compounds widely used in domestic products and construction materials (organophosphorus flame retardants (OPFR), phthalates, alkylphenols and bisphenol A), applied for pest control in cities (pesticides) and emitted through car exhausts (polycyclic aromatic hydrocarbons, PAHs) or smoking (nicotine). Contaminants were liquid-liquid extracted from nasal lavages and analysed using gas chromatography coupled to tandem mass spectrometry (GC-MS/MS). All 29 individuals inhabiting in Barcelona city had phthalates and bisphenol A at concentrations up to 31,300 ng mL^-1 for diethylhexyl phthalate (DEHP) and 118 ng mL^-1 for BPA. Individual PAHs, OPFR and alkylphenols had median values below their MQLs except for 2-ethylhexyldiphenyl phosphate (EHDPhP) with a median of 1.47 ng mL^-1. Nicotine was detected at the highest concentrations in all active smokers (median 2.16 ng mL^-1). Contrarily, pesticides were sporadically detected. Nasal lavages revealed to be an appropriate indicator likely to reflect exposure to dust and air contaminants.

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

Polycyclic aromatic hydrocarbons (PAHs) bound in dust retained in air-conditioning unit filters from 13 households in Greater Doha, Qatar, were quantified using GC-MS spectrometry. The median concentrations of ∑₁₆PAH and ∑₇PAH were 218.0 ng g^-1 (± 125.3) and 112.1 ng g^-1 (± 60.2) dry weight, respectively. Results show that except one sample, three- and four-benzene-ring PAHs were dominant in all dust samples. Phenanthrene, anthracene, pyrene, benzene(a)anthracene, and chrysene were dominant in 12 samples with maximum concentrations of 69.7 ng g^-1 (± 24.0), 92.9 ng g^-1 (± 28.1), 60.4 ng g^-1 (± 14.7), 38.6 ng g^-1 (± 7.3), and 14.7 ng g^-1 (± 3.5), respectively. Benzo(k)fluoranthene has the most abundance of the quantified PAHs in the dust samples accounting for 19% of the total PAHs. Although Kriging interpolation shows a spatial variation of PAHs from north to south of Greater Doha, the mean concentrations in both directions were statically insignificant. Five samples displayed levels of benzo(a)pyrene (BaP) with maximum and median concentrations at 110.8 ng g^-1 and 49.9 (± 28.4) dry weight, respectively. Benzo(a)pyrene equivalent approach [Formula: see text] was applied to assess carcinogenic exposure, and the resulting values (1.3-116.4 ng g^-1) indicate that the levels observed were below the values reported for other countries within the region. Estimated daily ingestion (EDI) rates of PAHs retained in ACU filters were assessed for five age-groups < 1, 1-2, 3-6, 11-16, and > 19 years and were 0.39 (± 0.1), 0.33 (± 0.1), 0.20 (± 0.02), 0.07 (± 0.02), and 0.05 (± 0.01) ng kg^-1/day, respectively. Source apportionment estimate indicates PAHs bound in dust retained in ACU filters are originated from pyrogenic sources.

Semi-volatile organic compounds in infant homes: Levels, influence factors, partitioning, and implications for human exposure

While infants are developing, they are easily affected by toxic chemicals existing in their environments, such as semi-volatile organic compounds (SVOCs): phthalates, polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs), and organophosphate esters (OPEs). However, the specific living environment of infants, including increased plastic products and foam floor mats, may increase the presence of these chemicals. In this study, 68 air, dust, and window film samples were collected from homes, with 3- to 6-month-old infant occupants, to analyze phthalates, PAHs, PBDEs, and OPEs. High detection rates and concentrations suggest that these SVOCs are widespread in infant environments and are associated with cooking methods, smoking habits, the period of time after decoration, and room floors. The partitioning behavior of SVOCs indicates that the logarithms of the dust/gas-phase air partition coefficient (logK_D) and the window film/gas-phase air partition coefficient (logK_F) in homes are not at an equilibrium state when the logarithm of the octanol/air partition coefficient (logK_OA) is less than 8 or greater than 11. Considering the 3 exposure routes, ingestion and dermal absorption have become the main routes of infant exposure to phthalates and OPEs, and ingestion and inhalation have become the dominant routes of exposure to PAHs and PBDEs. The total carcinogenic risk of SVOCs, which have carcinogenic toxicities, via ingestion and dermal absorption for infants in homes exceeds the acceptable value, suggesting that the current levels of these SVOCs in homes might pose a risk to infant health.

Indoor Sources of Air Pollutants

People spend an average of 90% of their time in indoor environments. There is a long list of indoor sources that can contribute to increased pollutant concentrations, some of them related to human activities (e.g. people's movement, cooking, cleaning, smoking), but also to surface chemistry reactions with human skin and building and furniture surfaces. The result of all these emissions is a heterogeneous cocktail of pollutants with varying degrees of toxicity, which makes indoor air quality a complex system. Good characterization of the sources that affect indoor air pollution levels is of major importance for quantifying (and reducing) the associated health risks. This chapter reviews some of the more significant indoor sources that can be found in the most common non-occupational indoor environments.

Indoor vs. outdoor airborne element array: A novel approach using moss bags to explore possible pollution sources

This study investigated by the moss-bag approach the pattern of air dispersed elements in 12 coupled indoor/outdoor exposure sites, all located in urban and rural residential areas. The aims were to discriminate indoor vs. outdoor element composition in coupled exposure sites and find possible relation between moss elemental profile and specific characteristics of each exposure site. Elements were considered enriched when in 60% of the sites, post-exposure concentration exceeded pre-exposure concentration plus two folds the standard deviation. Of the 53 analyzed elements, 15 (As, B, Ca, Co, Cr, Cu, Mn, Mo, Ni, Sb, Se, Sn, Sr, V, Zn) were enriched in moss exposed outdoor, whereas a subset of 7 elements (As, B, Cr, Mo, Ni, Se, V) were enriched also in indoor moss samples. The cluster analysis of the sites based on all elements, clearly separated samples in two groups corresponding to mosses exposed indoor and outdoor, with the latter generally exceeding the first. Among outdoor sites, urban were most impacted than rural; whereas other factors (e.g., heating and cooking systems, building material, residence time and family life style) could affect element profile of indoor environments. Based on the indoor/outdoor ratio, As derived from outdoor and indoor sources, B, Mo and Se were enriched mostly in outdoor sites; Ni, Cr and V were specifically enriched in most indoor samples, supporting the presence of indoor emitting sources for these elements. A PCA of all indoor sites based on enriched elements and site characteristics showed that traffic affected indoor pollution in urban areas. The moss bag approach provided useful information for a global assessment of human exposure.

Mutagenicity of indoor air pollutants adsorbed on spider webs

In this study, air pollutants were determined on spider webs collected from six indoor sites in the Lower Silesia region, southwest Poland. In order to assess the mutagenicity (M) of the collected samples, the standard Salmonella assay was used with two Salmonella typhimurium strains, TA98 and YG1041. The assays were conducted with and without metabolic activation (S9 mix). The presence of 15 polycyclic aromatic hydrocarbons (PAHs) and PAH-derivatives (nitro-PAHs; NPAHs) on spider webs was also assessed at the studied sites. The total PAH content of collected samples ranged from 1.65 to 51.75 µg g^-1; the total NPAH content ranged from 0.22 to 2.44 μg g^-1. The highest PAH concentration was found at two sites: a basement with coal heating (S4) and a garage (S6). Samples from these two sites were also characterized by the highest mutagenicity values in TA98 strain (65,127 and 35,565 revertants/g of web in the absence and presence of S9 mix, respectively, for S4 and 54,753 and 46,262 revertants/g, respectively, for S6). For strain YG1041, the highest values were obtained in a basement with coal heating; values were 233,748 and 185,321 revertants/g of web in the absence and presence of S9 mix, respectively. The concentration of PAHs was significantly correlated with the mutagenicity (M) of the web samples collected. Reassuming, people are exposed to substances with possible carcinogenic properties and potential adverse health effect through the ambient air due to vehicular traffic, heating systems, cooking habits etc. The application of spider webs sampling could bring the very important information regarding the possible health effect associated with indoor air, making these kind of studies cheap and reliable.

Contamination assessment and health risk of arsenic exposure to stairway dust in the zinc smelting district, Northeast China

Stairway dust samples were collected from residential communities in Huludao city to investigate population health risk of arsenic (As) exposure through stairway dust. ArcGIS software was used to analyze As spatial distribution in Huludao city. Hazard index was applied to assess health risk due to exposure to As in stairway dust. The results were that As concentrations ranged from 13.26 to 237.58 mg kg^-1, and the mean value was 59.64 mg kg^-1, which was seven times as high as the background value of Liaoning Province. The pattern of spatial distribution was concentric rings as the center of Huludao zinc plant, with the extension to the northeast and southwest. The average value of I_geo was 2.176, which fell into moderately polluted level. For non-carcinogenic risk, the hazard indexes were less than 1, indicating that there was almost no health risk for residents exposed to stairway dust. But population risk exposure to dust would increase rapidly with exposure time in stairway. The highest contribution to the overall figure of non-carcinogenic risk and carcinogenic risk appeared to be ingestion of substrate particles followed by inhalation pathway and dermal absorption of As in dust samples. And for carcinogenic risk, the risk values were lower than the threshold range of EPA's safe limits (1 × 10^-6 and 1 × 10^-4), suggesting that potential cancer risk of As due to exposure to stairway dust can be acceptable.

Chemical and organic characteristics of PM2.5 particles and their in-vitro cytotoxic effects on lung cells: The Middle East dust storms in Ahvaz, Iran

There are very few reports about the effect of PM_2.5 particles carried by the Middle East dust storms on lung cells. This study aimed to investigate the chemical properties and in-vitro cytotoxic effects of PM_2.5 extracts. Water-soluble fraction and organic solvent-extractable components of the samples collected from the city of Ahvaz, Khuzestan Province, Iran, during the normal and dust storm days of the winter of 2016 were analyzed and then applied on the human lung epithelial cell line (A549). The chemical properties and the cytotoxicity were analyzed by ICP-OES and Lactase Dehydrogenase (LDH) assay, respectively. The results of the independent t-test showed significantly higher mean cytotoxicity in the samples of normal days than that of dust storm days. It could be due to the fact that the cells were exposed to the same amount of water-soluble extract, whether it be from a normal day or a dust storm day, and since the normal air of Ahvaz is severely affected by traffic and industrial pollutants, its normal day samples showed stronger cytotoxic effect. The results of the Kruskal-Wallis test showed that cytotoxic effect increased with the particulate concentration. The highest cytotoxicity levels observed at 62, 125, and 250 μg/mL concentrations after 24-h incubation were 17% (belonging to a dust storm day), 37% (belonging to a normal day), and 47% (belonging to a dust storm day), respectively Since PAH compounds were measured in the particulate phase, their amount was naturally correlated with the quantity of particulates. However, it was observed that the samples of normal days contained the species with stronger human carcinogens ΣPAHs = 0.82 ng/m³.The results of one-way ANOVA showed a significant difference between the incubation times regarding the resulted cytotoxicity levels. In general, as the incubation duration increased, so did the cytotoxicity level. Although normal day particulates had a greater cytotoxic effect on A549 cell line, dust storm days are associated with higher levels of health risk; simply because during dust storms, people inhale much larger amounts of particulates.

Differential occurrence, profiles and uptake of dust contaminants in the Barcelona urban area

Dust is a complex but increasingly used matrix to assess human exposure to organic contaminants both in indoor and outdoor environments. Knowledge concerning the effects of organic pollution towards health outcome is crucial. This study is aimed to determine the presence of legacy compounds (DDTs and polychlorinated biphenyls, PCBs), compounds used in recent times (organophosphorous flame retardants, organophosphorous pesticides, BPA, phthalates and alkylphenols) and compounds originated from combustion processes (polycyclic aromatic hydrocarbons, PAHs) as well as nicotine in indoor environments along the metropolitan area of Barcelona. Monitored sites include public areas with high turnout (high schools, museums samples) and libraries and private spaces (houses and cars). Almost all compounds (57 over the 59 targeted) were found in each dust sample and libraries and schools were the most contaminated, with concentrations of ∑phthalates and ∑OPFRs up to 15 and 10 mg g^-1, respectively. One-way ANOVA tests, Tukey contrasts and principal component analysis (PCA) revealed that sampling place influenced the observed contamination profiles and public and private environments were clearly differentiated. Finally, based on the concentrations detected, a deterministic calculation was performed to estimate the total daily intakes of each compound via dust. This information was used to evaluate the human exposure for toddlers, teenagers and adult workers. Consistently, the highest concentrations coming from plasticisers and flame retardants gave the major exposure rates. As expected, toddlers were the most affected group followed by museum and library workers, although the levels were below the reference doses.

Comparison of sorption kinetics of PAHs by sorptive sinks and caco-2 cell and the correlation between bioaccessibility and bioavailability of PAHs in indoor dust

Sorptive sinks are extensively used in the bioaccessibility of organic contaminants, but their suitability for simulating the intestinal cell is seldom reported. In the present study, the sorption efficiency of PAHs by sorptive sinks including silica, poly(ethylene-co-vinyl acetate) (polyE), tenax, and C18 were compared with that by caco-2 cells. The elimination rate constants of phenanthrene, fluoranthene, pyrene, benzo(a)pyrene by caco-2 cell were 0.0417 ± 0.006 min^-1, 0.0411 ± 0.0074 min^-1, 0.0362 ± 0.006 min^-1, and 0.0526 ± 0.0037 min^-1, respectively, which were more closely to that of silica and polyE compared to other materials. This indicated that these materials might be the preferable sorptive sinks to simulate absorption of PAHs by intestinal cells. The bioaccessibility of phenanthrene, fluoranthene, pyrene, benzo(a)pyrene in indoor dust ranged from 15.5-43.5%, 9.10-38.8%, 10.0-37.9%, and 6.00-21.9%, respectively, based on physiologically based extraction test (PBET) and the sorptive sinks added in the intestinal solution led to 1.17 to 8.47-fold enhancement of bioaccessibility. The correlation of in vivo PAHs relative bioavailability (RBA) and in vitro digestion bioaccessibility with or without the sorptive sinks of indoor dust were measured, and the results indicated that silica and polyE were more likely to predict PAHs RBA of indoor dust, which was consistent with the results of sorption kinetics assay. The present results indicate that silica and polyE have the potential to simulate caco-2 cell and the inclusion of these materials in the PBET is likely to predict PAHs RBA in indoor dust. Capsule: Silica and polyE were more likely to simulate absorption of PAHs by intestinal cells, and to predict PAHs RBA of indoor dust.

An overview of research and development themes in the measurement and occurrences of polyaromatic hydrocarbons in dusts and particulates

Polycyclic aromatic hydrocarbons (PAHs) are a group of organic compounds consisting of two or more fused aromatic rings and are probably one of the most studied groups of organic chemicals in environmental research. PAHs originate mainly from anthropogenic processes, particularly from incomplete combustion of organic fuels. PAHs are distributed widely in particulate matter. Due to widespread sources and persistent characteristics, PAHs disperse through atmospheric transport and exist almost everywhere. Human beings are exposed to PAH mixtures in gaseous or particulate phases in ambient air. Long-term exposure to high concentrations of PAHs is associated with adverse health problems. This review identifies the main research and development themes in the measurement and occurrences of PAHs in dusts and particulates using a new approach to carrying out a literature review where many peer-review publications have been produced. The review extracts the most important research themes from a literature search using a combination of text mining and a more detailed review of selected papers from within the identified themes.

Comprehensive method for the analysis of multi-class organic micropollutants in indoor dust

In the last decades, there has been an increasing concern about the human exposure to indoor dust because it has been observed that its contact or ingestion represents an important exposure source to several contaminants. The principal aim of this study was to evaluate the presence of multi pollutants in indoor dust. Therefore, an efficient multi-residue analytical method based on gas chromatography-electron ionisation-tandem mass spectrometry (GC-EI-MS/MS) was developed for the quantitative determination of 59 pollutants in house dust. The studied compounds belong to different families which have been reported as dangerous due to their possible effects for human health (endocrine disruption, neurotoxicity, mucosa-irritating effects, etc.). They are plasticisers, pesticides, flame retardants or polycyclic aromatic hydrocarbons, and reflect compounds used in construction materials, domestic goods or coming from outdoor air accumulation in indoor environments. The optimised methodology was simple, reliable and sensitive and was tested to evaluate the presence of contaminants in house dust samples collected in the area of Barcelona (Spain). Among all compounds studied, 54 contaminants were detected, being phthalates the group of compounds encountered at the highest concentrations, followed by organophosphorus flame retardants and bisphenol A.

Assessment of sediment mutagenicity in areas under the influence of a contaminated site undergoing a remediation process

Soil contamination enters aquatic ecosystems affecting sediment quality. The region studied is the Taquari River, Brazil, close to a site contaminated by wood preservatives, with a runoff route into the river. The first stage of the remediation process (In this article, the terms intervention and remediation have been used with slightly different meanings. We consider intervention to be the first phase of the remediation process, which aims to remove active sources) was an intervention to remove the main active sources. The Salmonella/microsome assay and polycyclic aromatic hydrocarbons (PAHs) were used to assess sediment quality in organic extracts during different intervention phases. The strains used were TA98, TA97a, and TA100 with and without S9mix (±S9). The results indicated the presence of pro-mutagens at site Ta010 (closest to the contaminated site) in all samplings, and the highest result occurred before intervention for TA100 + S9 (1,672 ± 215.9 rev/g). These values decreased during (83 ± 23.6 rev/g) and after this process (403 ± 105.9 rev/g), although the PAHs concentrations increased. Samples from this site presented PAHs with a carcinogenic potential during the assessed periods. After intervention, Ta006 (4 km downstream from Ta010) showed the most significant mutagenesis for TA100 + S9 (764 ± 230.2 rev/g) and, although the total PAHs values were lower, the species considered carcinogenic had higher concentrations. Mutagenesis predicted values of PAHs confirmed that carcinogenic species were predominantly detected by TA100, and the other PAHs by TA97a strains. Marked contaminant release to the river was observed, mainly in Ta010 at different periods. Mutagenicity and PAHs values in an internal stream, upstream from Ta010, showed a dispersion route of these agents. Thus, contamination in Ta010 and possible contribution to Ta006, after intervention, provides a warning regarding environmental quality in the region. Environ. Mol. Mutagen. 59:625-638, 2018. © 2018 Wiley Periodicals, Inc.

Characteristics and health risk assessment of heavy metals exposure via household dust from urban area in Chengdu, China

To investigate the characteristics of heavy metals (Cr, Cd, Pb, Zn, Cu and Ni) in household dust in urban household environment of Chengdu, China, 90 household dust samples were collected from 6 districts of the city. The information of houses and residents were also recorded during dust sampling to identify the correlations between heavy metals in household dust and the house attributes. And also the principal component analysis and cluster analysis for sources and impactor factors. The concentrations of Pb (123mg·kg^-1), Zn (675mg·kg^-1), Cu (190mg·kg^-1), Cr (82.7mg·kg^-1), Cd (2.37mg·kg^-1) and Ni (52.6mg·kg^-1) in household dust are in low or moderate levels when compare with that from other counties or areas. The heavy metals of household dust samples from Chengdu is higher concentrations than that in the street dust from Chengdu, except for Cr. Statistical analysis result showed traffic sources and corrosion of alloys are important factors contributing to the rise concentrations of heavy metals in household dust. In addition, there is negative correlation (p<0.05) between the heavy metals concentrations and floor levels. The ingestion is the important pathway for Pb, Zn, Cu and Ni via household dust exposure to the residents, and the dermal contact was identified as a main route for Cr and Cd in household dust exposure to the residents. There are minor non-carcinogenic and carcinogenic risks from the heavy metals in household dust for the residents in Chengdu.

Influence of indoor environmental factors on mass transfer parameters and concentrations of semi-volatile organic compounds

Semi-volatile organic compounds (SVOCs) in indoor environments can partition among the gas phase, airborne particles, settled dust, and available surfaces. The mass transfer parameters of SVOCs, such as the mass transfer coefficient and the partition coefficient, are influenced by indoor environmental factors. Subsequently, indoor SVOC concentrations and thus occupant exposure can vary depending on environmental factors. In this review, the influence of six environmental factors, i.e., indoor temperature, humidity, ventilation, airborne particle concentration, source loading factor, and reactive chemistry, on the mass transfer parameters and indoor concentrations of SVOCs was analyzed and tentatively quantified. The results show that all mass transfer parameters vary depending on environmental factors. These variations are mostly characterized by empirical equations, particularly for humidity. Theoretical calculations of these parameters based on mass transfer mechanisms are available only for the emission of SVOCs from source surfaces when airborne particles are not present. All mass transfer parameters depend on the temperature. Humidity influences the partition of SVOCs among different phases and is associated with phthalate hydrolysis. Ventilation has a combined effect with the airborne particle concentration on SVOC emission and their mass transfer among different phases. Indoor chemical reactions can produce or eliminate SVOCs slowly. To better model the dynamic SVOC concentration indoors, the present review suggests studying the combined effect of environmental factors in real indoor environments. Moreover, interactions between indoor environmental factors and human activities and their influence on SVOC mass transfer processes should be considered.

Health impact assessment from building life cycles and trace metals in coarse particulate matter in urban office environments

This study intends to determine the health impacts from two office life cycles (St.1 and St.2) using life cycle assessment (LCA) and health risk assessment of indoor metals in coarse particulates (particulate matter with diameters of less than 10µm). The first building (St.1) is located in the city centre and the second building (St.2) is located within a new development 7km away from the city centre. All life cycle stages are considered and was analysed using SimaPro software. The trace metal concentrations were determined by inductively couple plasma-mass spectrometry (ICP-MS). Particle deposition in the human lung was estimated using the multiple-path particle dosimetry model (MPPD). The results showed that the total human health impact for St.1 (0.027 DALY m^-2) was higher than St.2 (0.005 DALY m^-2) for a 50-year lifespan, with the highest contribution from the operational phase. The potential health risk to indoor workers was quantified as a hazard quotient (HQ) for non-carcinogenic elements, where the total values for ingestion contact were 4.38E-08 (St.1) and 2.59E-08 (St.2) while for dermal contact the values were 5.12E-09 (St.1) and 2.58E-09 (St.2). For the carcinogenic risk, the values for dermal and ingestion routes for both St.1 and St.2 were lower than the acceptable limit which indicated no carcinogenic risk. Particle deposition for coarse particles in indoor workers was concentrated in the head, followed by the pulmonary region and tracheobronchial tract deposition. The results from this study showed that human health can be significantly affected by all the processes in office building life cycle, thus the minimisation of energy consumption and pollutant exposures are crucially required.

Use of Monte Carlo analysis in a risk-based prioritization of toxic constituents in house dust

Many chemicals have been detected in house dust with exposures to the general public and particularly young children of potential health concern. House dust is also an indicator of chemicals present in consumer products and the built environment that may constitute a health risk. The current analysis compiles a database of recent house dust concentrations from the United States and Canada, focusing upon semi-volatile constituents. Seven constituents from the phthalate and flame retardant categories were selected for risk-based screening and prioritization: diethylhexyl phthalate (DEHP), butyl benzyl phthalate (BBzP), diisononyl phthalate (DINP), a pentabrominated diphenyl ether congener (BDE-99), hexabromocyclododecane (HBCDD), tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) and tris(2-chloroethyl) phosphate (TCEP). Monte Carlo analysis was used to represent the variability in house dust concentration as well as the uncertainty in the toxicology database in the estimation of children's exposure and risk. Constituents were prioritized based upon the percentage of the distribution of risk results for cancer and non-cancer endpoints that exceeded a hazard quotient (HQ) of 1. The greatest percent HQ exceedances were for DEHP (cancer and non-cancer), BDE-99 (non-cancer) and TDCIPP (cancer). Current uses and the potential for reducing levels of these constituents in house dust are discussed. Exposure and risk for other phthalates and flame retardants in house dust may increase if they are used to substitute for these prioritized constituents. Therefore, alternative assessment and green chemistry solutions are important elements in decreasing children's exposure to chemicals of concern in the indoor environment.

Occupational health risk assessment and exposure to floor dust PAHs inside an educational building

Polycyclic aromatic hydrocarbons (PAHs) settled in floor dust play an important role in human health. Although many studies investigated occupational exposure to PAHs, no attempts have been made to report PAHs concentrations as well as their health risk assessment inside an educational building in Jordan. Therefore, the main objective of this study is to report the PAHs concentrations in floor dust and evaluate their exposure and health risk inside the Department of Physics of the University of Jordan. The total PAHs concentrations ranged from 714 to 5246ng/g. The high concentrations were observed inside some offices, where tobacco smoking took place. One of those offices was previously renovated and some petrochemical liquids were used to remove the remaining glue from a previous carpet. Interestingly, the PAHs inside these offices were higher than those reported inside lecture rooms and the workshop area, where extensive activates of heavy machinery and use of petroleum products (such as lubricating oils). This implies that the health effects of exposure to tobacco smoking inside small micro-environmental places that are poorly ventilated can be very harmful. We also made a simple exposure and health risk assessment for the ingested dust (hand-to-mouth) by calculating the Estimated Daily Intake (EDI) and benzo(a)pyrene equivalent carcinogenic power (BaPE). The total EDI was less than 3.75ng/kg-bw/day whereas the BaPE was less than 385ng/g. These values are lower than what was reported in some previous studies in Europe and Asia.

Assessment of polycyclic aromatic hydrocarbons in indoor dust from varying categories of rooms in Changchun city, northeast China

Sixteen polycyclic aromatic hydrocarbons (PAHs) were isolated from indoor dust from various categories of rooms in Changchun city, northeast China, including dormitory, office, kitchen, and living rooms. PAH concentrations ranged from 33.9 to 196.4 μg g^-1 and 21.8 to 329.6 μg g^-1 during summer and winter, respectively, indicating that total PAH concentrations in indoor dust are much higher than those in other media from the urban environment, including soils and sediments. The percentage of five- to six-ring PAHs was high, indicating that PAHs found in indoor dust mainly originate from pyrolysis rather than a petrogenic source. Rooms were divided into three groups using cluster analysis on the basis of 16 PAH compositions, namely smoke-free homes, homes exposed to smoke and offices. Results showed that the source of PAHs in smoke-free residential homes is primarily the burning of fossil fuels. In addition to the burning of fossil fuels, biomass combustion and cooking contributed to PAHs in houses exposed to smoke (including kitchens). Motor vehicles are an additional source of PAHs in offices because of greater interactions with the outdoor environment. The results of health risk assessment showed that the cancer risk levels by dermal contact and ingestion are 10⁴- to 10⁵-fold higher than that by inhalation, suggesting that ingestion and dermal contact of carcinogenic PAHs in dust are more important exposure routes than inhalation of PAHs from air. Although the results showed high potential of PAH concentrations in indoor dust in Changchun for human health risk, caution should be taken to evaluate the risk of PAHs calculated by USEPA standard models with default parameters because habitation styles are different in various categories of rooms.

Polycyclic aromatic hydrocarbons (PAHs) in indoor dust samples from Cities of Jeddah and Kuwait: Levels, sources and non-dietary human exposure

This study reports levels and profiles of polycyclic aromatic hydrocarbons (PAHs) in dust samples collected from three different microenvironments (cars, air conditioner (AC) filters and household floor dust) of Jeddah, Saudi Arabia (KSA) and Kuwait. To the best of our knowledge, this is first study reporting PAHs in indoor microenvironments of KSA, which makes these findings important. Benzo(b)fluoranthene (BbF), benzo(a)pyrene (BaP), phenanthrene (Phe), and pyrene (Pyr) were found to be the major chemicals in dust samples from all selected microenvironments. ΣPAHs occurred at median concentrations (ng/g) of 3450, 2200, and 2650 in Saudi AC filter, car and household floor dust, respectively. The median levels (ng/g) of ΣPAHs in Kuwaiti car (950) and household floor (1675) dust samples were lower than Saudi dust. The PAHs profile in Saudi dust was dominated by high molecular weight (HMW) (4-5 ring) PAHs while in Kuwaiti dust 3 ring PAHs have marked contribution. BaP equivalent, a marker for carcinogenic PAHs, was high in Saudi household floor and AC filter dust with median levels (ng/g) of 370 and 455, respectively. Different exposure scenarios, using 5th percentile, median, mean, and 95th percentile levels, were estimated for adults and toddlers. For Saudi and Kuwaiti toddlers worst exposure scenario of ΣPAHs was calculated at 175 and 85ng/kg body weight/day (ng/kgbw/d), respectively. For Saudi toddlers, the calculated worst exposure scenarios for carcinogenic BaP (27.7) and BbF (29.3ng/kgbw/d) was 2-4 times higher than Kuwaiti toddlers. This study is based on small number of samples which necessitate more detailed studies for better understanding of dynamics of PAHs in the indoor environments of this region. Nevertheless, our finding supports the ongoing exposure of organic pollutants to population that accumulates indoor.

Polycyclic aromatic hydrocarbons and trace metals in mosque's carpet dust of Riyadh, Saudi Arabia, and their health risk implications

The main objectives of this work were to identify and determine the concentrations of polycyclic aromatic hydrocarbons (PAHs) and trace metals in carpet dust samples from various mosques of the city of Riyadh and to assess the health risks associated with the exposure to these pollutants. Therefore, 31 samples of mosque's carpet dust from Riyadh were collected. The results showed that 14 PAHs were present in the dust samples with concentrations ranged from 90 to 22,146 ng g^-1 (mean = 4096 ± 4277 ng g^-1) where low molecular weight compounds were dominant. The presence of PAHs were in the order of naphthalene > chrysene and benzo(b)fluoranthene > benzo(a)pyrene > acenaphthene and benzo(k)fluoranthene > pyrene and the absence of indeno(1,2,3-cd)pyrene and dibenz(a,h)anthracene. The diagnostic ratio coupled with principle component analysis (PCA) revealed mix sources of petrogenic from traffic, stack emission, and pyrogenic inputs from essence and perfumed wood burning. Trace metals were significant in the dust samples, and their concentrations decrease in the order of Zn, Mn, Cu, Cr, Pb, Ni, and V where Zn being the highest (94.4 ± 91.5 μg g^-1) and indium was the lowest (1.9 ± 9.3 μg g^-1). The trace metals were major in southern and central parts of Riyadh and followed the order of central Riyadh > southern Riyadh > western Riyadh > eastern Riyadh > northern Riyadh. Estimated risk based on the total PAHs was found to be 4.30 × 10^-11 for adult and 1.56 × 10^-11 for children. Elemental non-cancer risk for adults ranged from 7.9 × 10^-4 for Co to 7.58 × 10^-1 for Li and for children ranged from 3.70 × 10^-3 for Co to 3.54 for Li. Policy implication and mitigations of PAHs in Riyadh and Saudi Arabia were highlighted.

Molecular mechanisms of dust-induced toxicity in human corneal epithelial cells: Water and organic extract of office and house dust

Human corneal epithelial (HCE) cells are continually exposed to dust in the air, which may cause corneal epithelium damage. Both water and organic soluble contaminants in dust may contribute to cytotoxicity in HCE cells, however, the associated toxicity mechanisms are not fully elucidated. In this study, indoor dust from residential houses and commercial offices in Nanjing, China was collected and the effects of organic and water soluble fraction of dust on primary HCE cells were examined. The concentrations of heavy metals in the dust and dust extracts were determined by ICP-MS and PAHs by GC-MS, with office dust having greater concentrations of heavy metals and PAHs than house dust. Based on LC50, organic extract was more toxic than water extract, and office dust was more toxic than house dust. Accordingly, the organic extracts induced more ROS, malondialdehyde, and 8-Hydroxydeoxyguanosine and higher expression of inflammatory mediators (IL-1β, IL-6, and IL-8), and AhR inducible genes (CYP1A1, and CYP1B1) than water extracts (p<0.05). Extracts of office dust presented greater suppression of superoxide dismutase and catalase activity than those of house dust. In addition, exposure to dust extracts activated NF-κB signal pathway except water extract of house dust. The results suggested that both water and organic soluble fractions of dust caused cytotoxicity, oxidative damage, inflammatory response, and activation of AhR inducible genes, with organic extracts having higher potential to induce adverse effects on primary HCE cells. The results based on primary HCE cells demonstrated the importance of reducing contaminants in indoor dust to reduce their adverse impacts on human eyes.

Biological impact of environmental polycyclic aromatic hydrocarbons (ePAHs) as endocrine disruptors

Polycyclic aromatic hydrocarbons (PAHs) are often detected in the environment and are regarded as endocrine disruptors. We here designated mixtures of PAHs in the environment as environmental PAHs (ePAHs) to discuss their effects collectively, which could be different from the sum of the constituent PAHs. We first summarized the biological impact of environmental PAHs (ePAHs) found in the atmosphere, sediments, soils, and water as a result of human activities, accidents, or natural phenomena. ePAHs are characterized by their sources and forms, followed by their biological effects and social impact, and bioassays that are used to investigate their biological effects. The findings of the bioassays have demonstrated that ePAHs have the ability to affect the endocrine systems of humans and animals. The pathways that mediate cell signaling for the endocrine disruptions induced by ePAHs and PAHs have also been summarized in order to obtain a clearer understanding of the mechanisms responsible for these effects without animal tests; they include specific signaling pathways (MAPK and other signaling pathways), regulatory mechanisms (chromatin/epigenetic regulation, cell cycle/DNA damage control, and cytoskeletal/adhesion regulation), and cell functions (apoptosis, autophagy, immune responses/inflammation, neurological responses, and development/differentiation) induced by specific PAHs, such as benz[a]anthracene, benzo[a]pyrene, benz[l]aceanthrylene, cyclopenta[c,d]pyrene, 7,12-dimethylbenz[a]anthracene, fluoranthene, fluorene, 3-methylcholanthrene, perylene, phenanthrene, and pyrene as well as their derivatives. Estrogen signaling is one of the most studied pathways associated with the endocrine-disrupting activities of PAHs, and involves estrogen receptors and aryl hydrocarbon receptors. However, some of the actions of PAHs are contradictory, complex, and unexplainable. Although several possibilities have been suggested, such as direct interactions between PAHs and receptors and the suppression of their activities through other pathways, the mechanisms underlying the activities of PAHs remain unclear. Thus, standardized assay protocols for pathway-based assessments are considered to be important to overcome these issues.

Source apportionment and risk assessment of PM1 bound trace metals collected during foggy and non-foggy episodes at a representative site in the Indo-Gangetic plain

The concentration, spatial distribution and source of 13-PM1 bound trace metals (Fe, Cu, Mn, Cr, Zn, Cd, Ni, K, Mg, Na, Ca, Pb and V) and adverse health effects of 5-PM1 bound trace metals (Mn, Zn, Ni, Cr and Cd) collected during foggy and non-foggy episodes are presented. Twenty-four samples from each period (foggy and non-foggy episodes) were collected from Kanpur, a typical densely populated city and the most polluted representative site in the Indo-Gangetic plain of India, and were analyzed for carcinogenic (Ni, Cr and Cd) and non-carcinogenic metals (Mn and Zn). The average mass concentration of PM1 during foggy and non-foggy episodes was found to be 160.16±37.70 and 132.87±27.97μg/m(3). Source identification via principle component analysis suggested that vehicular emission and anthropogenic, industrial and crustal dust were the dominant sources in this region. During both episodes the decreasing order of hazard quotient (Hq) for adult and children was as Mn>Cr>Cd>Ni>Zn. In a non-foggy episode the hazardous index (Hi) values of these 5 trace metals were found to be ~3.5 times higher than a foggy episode's exposed population, respectively. In a foggy episode, due to the exposure to total carcinogenic trace metals (Ni, Cr and Cd) present in the ambient air, 95% probability total incremental lifetime cancer risks (TIlcR) were ~687 cancer cases and ~402 cancer cases per million in the adult population and children population respectively. These cancer cases were ~1.6 times higher than a non-foggy episode's exposed population.

Mechanisms of housedust-induced toxicity in primary human corneal epithelial cells: Oxidative stress, proinflammatory response and mitochondrial dysfunction

Human cornea is highly susceptible to damage by dust. Continued daily exposure to housedust has been associated with increasing risks of corneal injury, however, the underlying mechanism has not been elucidated. In this study, a composite housedust sample was tested for its cytotoxicity on primary human corneal epithelial (PHCE) cells, which were exposed to dust at 5-320μg/100μL for 24h. PHCE cell viability showed a concentration-dependent toxic effect, attributing to elevated intracellular ROS. Moreover, when exposed at >20-80μg/100μL, dust-induced oxidative damage was evidenced by increased malondialdehyde and 8-hydroxy-2-deoxyguanosine (1.3-2.3-fold) and decreased antioxidative capacity (1.6-3.5-fold). Alteration of mRNA expression of antioxidant enzymes (SOD1, CAT, HO-1, TRXR1, GSTM1, GSTP1, and GPX1) and pro-inflammatory mediators (IL-1β, IL-6, IL-8, TNF-α, and MCP-1) were also observed. Furthermore, the mitochondrial transmembrane potential was dissipated from 9.2 to 82%. Our results suggested that dust-induced oxidative stress probably played a vital role in the cytotoxicity in PHCE cells, which may have contributed to dust-induced impairment of human cornea.