Urban roadside dust samples from Dhaka City in Bangladesh were collected from a planned residential area (PRA), spontaneous residential area (SRA), commercial area (CA), and urban green area (UGA) in ...winter and summer to study how season and different urban land-use categories influence the concentrations of heavy metals (Cr, Mn, Co, Ni, Cu, Zn, As, and Pb) and different pollution indices. The dust samples were fractionated into <32 μm particles, extracted by acid digestion followed by estimation of heavy metals, using ICP-MS. Pollution indices were calculated from the metal concentrations, using standard protocols. The concentrations of heavy metals in roadside dust varied significantly (all p < 0.05), due to sampling seasons and the land-use category. Higher concentrations of heavy metals (Cr, Mn, Ni, Cu, Zn, and Pb) were found in the dust sampled during the winter season than in the summer season, except for As and Co. The geo-accumulation index (Igeo) indicated that the commercial area was heavily contaminated with Cu and Zn during the winter season. The contamination factor (CF) was higher for Cu and Zn in the CA, PRA, and SRA of Dhaka City in winter than in the summer season. The enrichment factor (EF) suggested that Mn and Co were the least enriched metals, and significant enrichment was seen for Cu and Zn for all land-use categories, both in summer and winter. A moderate potential ecological risk for Cu was estimated in CA and PRA in the winter season.
Atmospheric PM2.5 samples from Wuhan, China were collected during a winter period of February and a summer period of August in 2018. The average PM2.5 mass concentration in winter reached 112 ...μg/m3—about two-fold higher than that found in summer. Eight ionic species constituted 1/3 of PM2.5, whereas more than 85% represented secondary ionic aerosols (NO3−, SO42− and NH4+). Higher ratios of NO3−/SO42− (0.95–2.62) occurred in winter and lower ratios (0.11–0.42) occurred in summer showing the different contribution for mobile and stationary sources. Seventeen elemental species constituted about 10% of PM2.5, with over 95% Na, Mg, Al, Ca, Fe, K and Zn. Higher K-concentration occurred in winter indicating greater contribution from biomass and firework-burning. Carcinogenic risks by Cr, As, Cd, Ni and Pb in PM2.5 indicated that about 6.94 children and 46.5 adults among per million may risk getting cancer via inhalation during surrounding winter atmospheric sampling, while about 5.41 children and 36.6 adults have the same risk during summer. Enrichment factors (EFs) and elemental ratios showed that these hazardous elements were mainly from anthropogenic sources like coal and oil combustion, gasoline and diesel vehicles.
•The effect of polyethylene (HDPE) photolysis aging on pyrene sorption was studied.•Simulated sunlight irradiation caused morphological changes in HDPE.•Irradiation did not cause destructive ...oxidation of HDPE particles.•Pyrene sorption was greater for aged HDPE than for pristine HDPE.•Sunlight aging is a key factor for organic pollutants interacting with plastics.
The sorption and transport of environmental pollutants with microplastics (MPs) is a growing environmental concern due to the increased use and emissions of MPs and their high affinity toward many organic contaminants. This study examines the impacts of environmental aging of high-density polyethylene (HDPE) via sunlight irradiation on its molecular interactions with pyrene, a model hydrophobic organic pollutant. HDPE MPs were artificially aged under simulated sunlight irradiation for different exposure times. During aging treatments with simulated sunlight irradiation, morphological changes, such as cracks and rough surfaces, were induced on the HDPE particles; however, destructive oxidation was not observed. Batch sorption experiments were conducted on the aged and pristine MPs. Results reveal that pyrene sorption on MPs was enhanced for the aged HDPE particles and the sorption increases with increased irradiation time, indicating that aged HDPE has a higher sorption capacity than the pristine one. These results are attributed to the physical alteration in HDPE, which increases the surface area and promotes aqueous pyrene sorption on MPs. These results provide possible mechanistic explanations for the accumulation of hydrophobic organic pollutants with MPs in aquatic environments.
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The Shanghai subway metro system has brought great convenience to the city's travelling public, although passengers are exposed to airborne particles in this built micro-environment. However, ...investigations on the physicochemical characterization of PM2.5 air pollution in the Shanghai subway system are to date very limited. Three subway stations along the No. 7 line were selected as subway PM2.5 monitoring sites: Pan'guang, Shanghai University (SHU), and Jing'an, which are located in an outer suburban area, a suburban area and the urban area, respectively, airborne PM2.5 on the subway station platforms and in the ambient atmosphere above-ground was synchronously collected from 19th March to 4th, May, 2012. Cutting-edge techniques, including scanning electronic microscopy coupled with energy dispersive X-ray (SEM/EDX), inductively coupled plasma mass spectrometry (ICP-MS) and X-ray absorption near-edge structure (XANES) were employed to investigate microscopic characterization, chemical elements and speciation of the main heavy metals in subway PM2.5. Our results demonstrated that mass levels of PM2.5 in the subway stations were higher than that in ambient air. Mass levels of PM2.5 in the subway stations and in ambient air ranged from 49.17±19.7μg/m3 to 66.15±25.20μg/m3, and 24.52±3.3μg/m3 to 65.60±5.6μg/m3, respectively. The microscopic characterization of PM2.5 in ambient air and in subway stations showed marked differences. The PM2.5 in the subway stations was mainly composed of iron-containing particles and mineral particles, while the PM2.5 in ambient air largely consisted of mineral particles and soot aggregates. Fe was the most abundant element in subway PM2.5, followed by: major elements (mass level>100ng/m3) including Na, Mg, Al, K, Ca, Zn, Mn, Ba; sub-major elements (10ng/m3<mass level<100ng/m3) including Li, Cr, Ni,Cu, Ga, Sr, Pb; and minor elements (mass level<10ng/m3 ), Be, V, As, Se, Rb, Ag, Cd, Tl, Bi. The mass levels of Ca, Al and Zn in ambient PM2.5 were higher than those in subway PM2.5, however those of the remaining 26 measured elements in subway PM2.5 were higher than in ambient PM2.5. The speciation of Fe in PM2.5 was in the form of Fe2+, while for Cu, that in the finer fractions (<0.25, 0.5 and 1.0μm) was in the form Cu2+, but in the PM2.5 fraction itself, was as Cu1+.
•Mass levels of PM2.5 in the subway station were higher than in ambient air.•Fe was the most abundance element in subway PM2.5.•Speciation of Cu in the fine fraction (<0.25; 0.5 and 1.0μm) was in the form of Cu2+, but in PM2.5 was Cu1+.
Due to the COVID-19 pandemic in early 2020, large-scale industrial production has been stagnant and reduced, the urban air quality has been greatly improved. It provided an excellent opportunity to ...explore the effects of air pollutants on the sensitization of pollen allergen proteins in the environment.
Platanus
pollen grains sampled in the spring of 2019 and 2020 were used for detailed characterization and analysis. Scanning electron microscopy, Fourier transform infrared, X-ray spectroscopy (XPS), trypan blue staining, and western blot analysis were employed to characterize
Platanus
pollen protein released from pollen grains. Our data showed that the viability of the pollen grains in 2019 was lower compared that in 2020, and the pollen grains collected in 2019 had a higher absorption peak of protein functional groups. The XPS spectra assay result demonstrated that the binding energy of the high-resolution components had not variation on the surface of pollen grains, but relative content of nitrogen and peptide chain in the pollen grains sampled in 2019 were higher than in 2020. These results suggested that more protein in the pollen grains was released onto the surface of pollen grains. In addition, western blot assay showed that the expression of Pla a3 protein in pollen grains sampled in 2019 was significantly higher than that in 2020, revealing that air pollutants could enhance the expression of Pla a3 proteins in
Platanus
pollen.
Airborne particulate matter (PM) pollution often occurs in the wintertime in northern China, posing a potential threat to human health. To date, there are limited studies about the metals and ...inorganic ions to link source apportionments and health risk assessments in the different size-segregated PM samples. In this study, our samples were collected by a high-volume air sampler from 26 December 2018 to 11 January 2019 in a high population residential area (Beijing). Water-soluble inorganic ions, metal elements in the different size-segregated PM samples were determined for health risk assessments by inhalation of PM. During the sampling period in Beijing, the average concentrations of PM1.1 and PM1.1–2.0 were 39.67 ± 10.66 μg m−3 and 32.25 ± 6.78 μg m−3. Distinct distribution profiles characterized the different elements. The markers of coal combustion Pb, As, and Se had >52% of their mass concentration in PM1.1. The average mass ratios of (NO3− + NO2−)/SO42−, Cl−/Na+, Cl−/K+, and Cl−/(NO3− + NO2−) were 1.68, 6.58, 6.18, and 0.57, which showed that coal combustion and vehicle emissions were the main anthropogenic sources of PM in Beijing in winter. PM1.1 was the major contributor of Pb, Cd, and As for carcinogenic risks (CR) and hazard quotient (HQ). It was indicated that PM1.1 is more harmful than coarse PM. The toxic elements of Cr (VI) (1.12 × 10−6), V (0.69 × 10−6), and As (0.41 × 10−6) caused higher CR for children than Ni, Cd, Co, and Pb. Meanwhile, Pb (35.30 × 10−6) and Ni (21.07 × 10−6) caused higher CR for adults than As, Cr (VI), V, Co, and Cd, especially PM1.1. This study provides detailed composition data and the first report on human health in a high population residential area in Beijing.
Microplastics (MPs), small plastic particles resulting from the degradation of larger plastic items and from primary sources such as textiles, engineered plastic pellets, etc., have become a ...ubiquitous environmental pollutant. As their prevalence in the natural environment grows, concerns about their potential impacts on human health have escalated. This review discusses current research findings on the presence of MPs in organs such as the liver, blood, heart, placenta, breast milk, sputum, semen, testis, and urine, while also exploring plausible mechanisms of translocation. Furthermore, the review emphasizes the importance of understanding the potential toxicological effects of MPs on various physiological processes within these organs and their broader implications for human health. This review also examines the pathways through which MPs can enter and accumulate in human organs and bodily fluids, shedding light on the intricate routes of exposure and potential health implications. It is worth noting that the invasive medical procedures may permit direct access of MPs to the bloodstream and tissues, serving as a potential contamination source. However, it is evident that a comprehensive understanding of MPs’ invasion into human organs is vital for effective mitigation strategies and the preservation of both human health and the environment.
In this paper, a method to achieve the simultaneous quasi-phased-matched and group-velocity-matched second harmonic (SH) generation for femtosecond pulses at 1550 nm band was proposed. Under the ...polarization configuration (e+e-o), group velocity can be matched by control of temperature. The described coupling equations were applied to MgO doped periodically poled lithium niobate crystal, and the temporal and spectral characteristics of interaction waves were investigated. The fractional time delay between the fundamental frequency wave and the SH wave is as a function of temperature and the input pulse duration, resulting in optimal conversion efficiency. Such method can be useful for the broadband and efficient ultrafast SH pulse generation and pulse compression applications.
Air pollutants are perhaps the largest cause of diseases and death in the world today. Increasing urbanization and industrialization have caused an increase in number of diverse forms and types of ...new pollutants, which are difficult to detect and characterize due to their stench behaviour and complex sources of production. Such pollutants have been called emerging pollutants (EPs) and their list is ever increasing. Therefore, the understanding of the method of analysis and health implication of (EPs) in air is critical to providing a more robust understanding of exposure routes, regulations and mitigation. EPs in air discussed in this study are not in any way exhaustive but limited to emerging VOCs (including acrylonitrile, 1−3-butadiene, chloroform, dichloromethane, ethylene oxides, formaldehyde, toluene, trichloroethylene, 1,4-Dioxane) and metals (arsenic, manganese, and vanadium), ultrafine particles, micro- and nano- plastics, engineered nanoparticles, diesel/black carbon and bioaerosols. Occurrence, detection and health implications of these EPs in air are still unfolding due to limited monitoring studies, lack of standard methodology and regulations. To address this knowledge gap, authors conducted an in-depth review of available information. Their spatial distribution, analytical methods and health implications are discussed including the novel coronavirus (COVID-19) as a potential EP in air. The study concluded with highlights of gaps in knowledge and suggestions to key areas for future research. This information is of general interest to environmental scientists and of specific interest to both health and sanitation workers and policymakers at private, government and international organizations.
Pollen pollution and allergy are becoming prominent issues in China. However, few studies on pollinosis have been reported. As an allergen in the atmosphere, allergenic Humulus scandens pollen was ...collected from four districts of Shanghai, including Wusong (WS), Jiading (JD), Xujiahui (XJH) and Songjiang (SJ). The mass concentrations of SO2, NO2, O3, PM10, and PM2.5 (particulate matter with air dynamic diameter less than 10 and 2.5 µm, respectively) near the four sampling sites were also recorded during Humulus scandens pollen season. The allergenicity of the Humulus scandens pollen was assessed by using of a rat model and enzyme linked immunosorbent assay (ELISA). Relationships between the allergenicity and air pollutants were correlated. Our results demonstrated that the biological viability of the pollens collected from the four districts exhibited no significant differences. ELISA and dot blotting results further demonstrated that the serum of sensitized rats exhibited much higher immune-reactive response than that of control groups. Western blotting showed that the 15 KD (1KD = 1000 dalton) proteins of Humulus pollen led to the allergic response. The allergenic intensity of Humulus pollen protein from different samples followed the pattern: WS > JD > XJ > SJ. There was a negative relationship between the allergenicity of Humulus pollens and PM10 (R = -0.99) / PM2.5 (R = -0.73), and a positive relationship with O3 (R = 0.92). These data clearly showed that PM10 and PM2.5 could enhance Humulus pollen protein release, and O3 could aggravate the allergenicity of the Humulus pollen.
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