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

Urinary PAHs metabolites in Karakoram Highway's heavy traffic vehicle (HTV) drivers: evidence of exposure and health risk

The current study features PAHs exposure on Karakoram Highway, a route of utmost importance in Pakistan. The drivers of heavy traffic vehicles (HTV) on Karakoram Highway spend long hours amid dense traffic and therefore, inevitably inhale huge amount of PAH carcinogens. The urinary metabolites of PAHs in such drivers (meeting selection criteria n = 48) and a control group (n = 49) were comparatively profiled. The higher urinary biomarkers among ninety-six percent HTV drivers were evident of PAHs exposure. We observed elevated concentrations of urinary benzo[a]pyrene metabolites (3-OH-BaP = 3.53 ± 0.62 ng g^-1 creatinine and 9-OH-BaP = 3.69 ± 0.74 ng g^-1 creatinine) in HTV driver's samples compared to controls (0.85 ± 0.08 and 0.31 ± 0.03 ng g^-1 creatinine, respectively). Interestingly, urinary benzo[a]pyrene metabolites were detected in almost similar amount among HTV drivers irrespective of their working hours. A distinct smoking effect was manifested with rising urinary levels of 1-hydroxypyrene, 2-hydroxyphenanthrene, and 3-hydroxybenzo[a]pyrene with corresponding increase in driving hours per day. These metabolites exhibited characteristic exposures to low molecular weight volatile PAHs that are commonly found in vehicular exhaust. The elevated PAH body burden was directly linked to the nature of their job and the route-long environmental pollution on Karakoram Highway. Additionally, the poor economic status and smoking also increased HTV driver's health vulnerability and significantly declined their health capacity. There was conclusive evidence that HTV drivers were exposed to PAHs during a ride on Karakoram Highway, back and forth, an aspect not reported earlier.

Levels, distribution, sources and children health risk of PAHs in residential dust: A multi-city study in China

BACKGROUND

Polycyclic aromatic hydrocarbons (PAHs) are typical residential pollutants mainly from biofuel combustion that impose inevitable risk to children. The PAHs in residential dust is universal in most Chinese households with an obvious public health concern.

METHODS

In this observational study, a total of 235 residential dust samples from 8 Chinese cities (Panjin, Shijiazhuang, Lanzhou, Luoyang, Xi'an, Wuxi, Mianyang, and Shenzhen) were collected from April 2018 to March 2019, which were extracted and analyzed for 16 priority PAHs by HPLC/FD-UV. Diagnostic ratios, hierarchical clustering analysis and principal component analysis were applied simultaneously for source apportionments. Incremental lifetime cancer risk was employed to estimate children's health risks based on the assumed exposure scenarios. Spearman correlation, Mann-Whitney U test, Kruskal-Wallis H test and Partial Least Squares were used to screen the factors affecting the concentration of PAHs in residential dust.

RESULTS

The median concentration of ∑₁₆PAHs in residential dust from 8 cities was 44.11 μg/g (0.04 - 355.79 μg/g). ∑₁₆PAHs were found both higher in dust samples in heating season and from downwind households only in Mianyang (p < 0.05). The leading two sources of PAHs were combustion processes and automobile exhaust emissions based on four principal components that accounted for 74.29 % of the total variance. Indoor air environmental factors, household characteristics, and residents' behavioral lifestyles may be the influencing factors of residential dust PAHs. The carcinogenic risk of children aged 0 - 5 years, under the moderate exposure level of PAHs in residential dust, exceeded the acceptable level (10^-5 - 10^-4 for dermal contact and 10^-6 - 10^-5 for ingestion).

CONCLUSIONS

There was serious PAHs pollution in residential dust under actual living conditions in eight cities across China. More evidence-based measures were needed to control PAHs pollution to safeguard children's health according to appointed sources and influencing factors in residential dust.

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.

Bioaerosol and microbial exposures from residential evaporative coolers and their potential health outcomes: A review

Evaporative cooling is an energy efficient form of air conditioning in dry climates that functions by pulling hot, dry outdoor air across a wet evaporative pad. While evaporative coolers can help save energy, they also have the potential to influence human health. Studies have shown residential evaporative coolers may pull outdoor air pollutants into the home or contribute to elevated levels of indoor bioaerosols that may be harmful to health. There is also evidence that evaporative coolers can enable a diverse microbial environment that may confer early-life immunological protection against the development of allergies and asthma or exacerbate these same hypersensitivities. This review summarizes the current knowledge of bioaerosol and microbiological studies associated with evaporative coolers, focusing on harmful and potentially helpful outcomes from their use. We evaluate the effects of evaporative coolers on indoor bacterial endotoxins, fungal β-(1 → 3)-D-glucans, dust mite antigens, residential microbial communities, and Legionella pneumophila. To our knowledge, this is the first review to summarize and evaluate studies on the influence that evaporative coolers have on the bioaerosol and microbiological profile of homes. This brings to light a gap in the literature on evaporative coolers, which is the lack of data on health effects associated with their use.

New insight into human health risk from polycyclic aromatic hydrocarbons on surfaces of buildings and facilities for industrial legacy regeneration

Although many industrial heritage sites have been repurposed into attractive landscapes, the contamination and health risks from polycyclic aromatic hydrocarbons (PAHs) on industrial legacy surfaces remain unexplored. We collected 441wiping surface samples from 95 buildings and facilities at Beijing coking plant in China and found that the concentrations of 16 US EPA priority PAHs (∑₁₆PAHs) ranged from ND-982.16 and ND-4262.20 mg/m² on the surfaces of buildings and facilities, respectively. The main source of PAHs was the coking process, and spatial distribution of PAHs was consistent with ∑₁₆PAHs in the soil. The carcinogenic risks of BaP, DBA, BbF, BaA, Ind of the facilities remained as industrial heritage relics, and those of Bap, DBA and BbF in the buildings with commercial uses exceeded the acceptable level (10^-6). The hazard quotient of 9 PAHs was below the acceptable level (1.0). The remedial goals for BaP and DBA (0.11 mg/m²) and BbF, BaA and Ind (1.14 mg/m²) at the facility heritage relics were derived. Similarly, the RGs for the buildings with commercial uses of BaP, DBA and BbF were 0.16, 0.16, and 1.64 mg/m², respectively. Overall, we determined that carcinogenic PAHs on the surfaces of industrial legacy should be regulated for regeneration.

Characteristics and health effects of particulate matter emitted from a waste sorting plant

Solid waste components can be recycled in waste paper and cardboard sorting plants (WPCSP) through a multistep process. This work collected 15 samples every six days from each of the 9 points selected to study the processes taking place in a WPCSP (135 particulate matter samples total). Examining the concentration and size fraction of particulate matter (i.e., PM₁, PM_2.5 and PM₁₀) in WPCSP is an essential issue to notify policy makers about the health impacts on exposed workers. The major activities for increasing of the concentration of PM in various processing units in the WPCSP, especially in hand-picking routes I and II were related to manual dismantling, mechanical grinding, mechanical agitation, and separation and movement of waste. The results of this work showed that a negative correlation between temperature and particulate matter size followed the order PM₁₀ > PM_2.5 > PM₁. Exposure to PM_2.5 and PM₁₀ in the WPCSP lead to possible risk (HI = 5.561 and LTCRs = 3.41 × 10^-6 to 9.43 × 10^-5 for PM_2.5 and HI = 7.454 for PM₁₀). The exposure duration and the previous concentrations had the most effect on the ILCRs and HQs for PM_2.5 and PM₁₀ in all sampling sites. Hence, because WPCSP are infected indoor environments (I/O ratio > 1), the use of control methods such as isolation of units, misting systems, blower systems equipped with bag houses, protective equipment, a mechanical ventilation system, and additional natural ventilation can reduce the amount of suspended PM, enhance worker safety, and increase the recycling rate.

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.

Characteristics and assessing biological risks of airborne bacteria in waste sorting plant

Examining the concentration and types of airborne bacteria in waste paper and cardboard sorting plants (WPCSP) is an urgent matter to inform policy makers about the health impacts on exposed workers. Herein, we collected 20 samples at 9 points of a WPCSP every 6 winter days, and found that the most abundant airborne bacteria were positively and negatively correlated to relative humidity and temperature, respectively. The most abundant airborne bacteria (in units of CFU m^-3) were: Staphylococcus sp. (72.4) > Micrococcus sp. (52.2) > Bacillus sp. (30.3) > Enterococcus sp. (24.0) > Serratia marcescens (20.1) > E. coli (19.1) > Pseudomonas sp. (16.0) > Nocardia sp. (1.9). The lifetime average daily dose (LADD) for the inhalation and dermal routes for the intake of airborne bacteria ranged from 3.7 × 10^-3 ≤ LADD_Inhalation ≤ 2.07 × 10¹ CFU (kg d)^-1 and 4.75 × 10^-6 ≤ LADD_Dermal ≤ 1.64 × 10^-5 CFU (kg d)^-1, respectively. Based on a sensitivity analysis (SA), the concentration of airborne bacteria (C) and the exposure duration (ED) had the most effect on the LADD_Inhalation and LADD_Dermal for all sampling locations. Although the Hazard Quotient of airborne bacteria was HQ < 1, an acceptable level, the indoor/outdoor ratio (1.5 ≤ I/O ≤ 6.6) of airborne bacteria typically exceeded the threshold value (I/O > 2), indicating worker's exposure to an infected environment. Therefore, in the absence of sufficient natural ventilation the indoor ambient conditions of the WPCSP studied should be controlled by supplying mechanical ventilation.

The potential risks and exposure of Qinling giant pandas to polycyclic aromatic hydrocarbon (PAH) pollution

Rapid industrialization and urbanization have created a substantial urban-rural gradient for various pollutants. The Qinling Mountains are highly important in terms of biodiversity, providing habitat for giant pandas, which are endemic to China and are a widely recognized symbol for conservation. Whether polycyclic aromatic hydrocarbon (PAH) exposure risks regarding in situ animal conservation zones are affected by environmental pollution or even enhanced by the mountain-trapping effect requires further research. Our group carried out a large-scale investigation on the area ranging from Xi'an to Hanzhong across the giant panda habitat in the Qinling Mountains by collecting atmosphere, soil, bamboo, and fecal samples from different sites over a two-year period. The total toxicity of atmospheric PAHs and the frequencies of soil PAHs above effect range low (ERL) values showed a decreasing trend from urban areas to the central mountains, suggesting a distance effect from the city. The proportions of total 5- and 6-ring PAHs in the atmosphere were higher in the central mountainous areas than in the urban areas, while this difference was reversed in the soil. Health risk assessments showed that the incremental lifetime carcinogenic risks (ILCR) of PAH exposure by bamboo ingestion ranged from 2.16 × 10^-4 to 3.11 × 10^-4, above the critical level of 10^-4. Bamboo ingestion was the main driver of the PAH exposure risks. The concentration difference between bamboo and fecal samples provided a reference for the level of PAHs absorbed by the panda digestive system. Since the Qinling Mountains possess the highest density of giant pandas and provide habitats to many other endangered animal and plant species, we should not ignore the probability of health risks posed by PAHs. Monitoring the pollution level and reducing the atmospheric emissions of toxic pollutants are recommended actions. Further detailed research should also be implemented on pandas' health effects of contaminant exposure.

Human health risks from brominated flame retardants and polycyclic aromatic hydrocarbons in indoor dust

Exposure to dust particles containing toxic compounds is linked to serious health outcomes, including cancer. The purpose of this study was to determine if indoor dust from houses and cars contained harmful levels of brominated flame retardants (polybrominated diphenyl ethers, PBDEs) and polycyclic aromatic hydrocarbons (PAHs), and to assess their potential toxicity to adults and children. In Kuwait, the median concentration of total PBDEs (Ʃ14- PBDEs) was 408.55 μg PBDEs/kg dust in houses and twice as high in cars (838.52 μg PBDEs/kg dust), while total PAHs (Ʃ16-PAHs) were similar in houses (992.81 μg PAHs/kg) and cars (900.42 μg PAHs/kg). The PBDEs and PAHs concentrations in indoor dust were related to house age and square footage, car model year, and natural ventilation. Furthermore, a higher PBDEs concentration was associated with electronic devices that operate continuously, furniture containing foam treated with PBDEs, and cars that are parked outdoors, since PBDEs tend to be volatilized under these conditions. The PAHs concentration in indoor dust increased with smoking and proximity to major roads and industrial facilities, which are major PAHs sources. The hazard quotient and total cancer risk for PBDEs in indoor dust were within safe limits, but indoor dust with higher PAHs concentrations had hazard quotients from 5.51 to 11.23 and total cancer risk of 10^-3 for adults and children. We conclude that exposure to PAHs-contaminated indoor dust from houses and cars where smoking occurs can increase the cancer risk of adults and children.

On the nature of polycyclic aromatic hydrocarbons associated with sporting walkways dust: Concentrations, sources and relative health risk

Sporting walkways (SW) are a new innovation which may prove popular in many cities. As there is currently no information on possible health risks associated with their use, concentrations of polycyclic aromatic hydrocarbons (PAHs) associated with deposited dust sampled on SW in Jeddah, Saudi Arabia, have been measured and interpreted in relation to sources and cancer risk. The average ∑PAHs (16 compounds) ranged between 1357 ng/g in residential areas and 3764 ng/g in central urban areas, with suburban areas between. The congener profile and diagnostic ratios of PAHs indicate a predominant source associated with petroleum combustion (pyrogenic source), most probably vehicular emissions. Carcinogenic potential is estimated from the sum of carcinogenic compound concentrations weighted by their individual potency relative to benzo(a)pyrene, and is found to be similar to household dust sampled in the same city, and lower than many other indoor and outdoor (road) dusts sampled across the world.

Characteristics and health risk assessment of heavy metal contamination from dust collected on household HVAC air filters

Heavy metals associated with airborne particulate matter are detrimental to human health, but risk assessment is difficult due to the technical challenges of determining exposure rates. In houses and other buildings, the heating, ventilation and air conditioning (HVAC) system is equipped with an air filter that captures airborne particulate matter from the indoor air that enters the HVAC system. This study used the air filter dust as a proxy for the heavy metal exposure of children and adults, based on a household study in Kuwait. Air filter dust contained from 12.5 ± 5 mg Co/kg dust to 14 453 ± 5046 mg Fe/kg dust. Houses had high levels of Fe, Al, Zn, and Mn and relatively low concentrations of As and Co. Source apportionment revealed that metals in air filter dust were from natural and anthropogenic sources, including vehicular emissions, fossil fuel combustion, and metals-related industries. The total Hazard Index (HI; Σ exposure routes) for heavy metals was >1 for children and adults. Total cancer risks (TCR; Σ exposure routes) were 5.93 × 10^-3 (95% CI: 5.28 × 10^-3- 6.59 × 10^-3) for children and 5.16 × 10^-3 (95% CI: 4.59 × 10^-3 - 5.73 × 10^-3) for adults. Heavy metals, particularly the Cr and Pb concentrations, contribute to the non-carcinogenic and carcinogenic health risks of children and adults in Kuwait households.

Polycyclic aromatic hydrocarbon contamination along roads based on levels on vehicle window films

Vehicular emissions are known to be major contributors of airborne polycyclic aromatic hydrocarbons (PAHs) in cities. In order to assess the long-term contamination of PAHs along roads, we collected organic films from vehicle windows (26 private cars and 4 buses, in Shanghai, China) and used mathematical models to convert the film-bound PAH concentrations to the airborne PAH concentrations. The field measurements of airborne PAHs revealed that the partitioning and Level III fugacity model was suitable to estimate the airborne concentrations of high and low volatile PAHs (expect for naphthalene), respectively. The total airborne PAH concentrations along roads in Shanghai ranged from 0.83 to 3.37 μg m^-3 and the incremental lifetime cancer risks (ILCR_total) by exposure to PAHs along roads were greater than the USEPA lower guideline of 10^-6, indicating non-negligible carcinogenic risks to drivers and passengers, especially via ingestion processes. This study provided a practicable method to investigate long-term air contamination of PAHs in vehicles and along roads based on film-bound PAH on vehicle windows. In addition, it was also possible to investigate the health risk in vehicles as a result of exposure to PAHs. Comparisons of PAHs between roads and shipping lanes also facilitated the delineation of vehicular and shipping PAH inventories. A capsule that summarizes the main finding of the work: Investigating film-bound PAH on vehicle windows is a practicable pathway to investigate the long-term contamination of PAHs in vehicles and along roads. This method can not only simplify the sampling processes, but the model calculations. The results also enabled investigations into ILCR in vehicles and specified source apportionment of traffic PAHs.