MiR-140-5p/TLR4 /NF-κB signaling pathway: Crucial role in inflammatory response in 16HBE cells induced by dust fall PM2.5.

Fine atmospheric particles with a diameter of 2.5 µm or less (PM2.5) have a large specific surface area, and carry a variety of organic matter, heavy metals, minerals and bacteria. They are an important risk factor in human non-communicable disease. To explore the molecular regulatory mechanism of the airway inflammation caused by PM2.5, an in vitro human bronchial epithelial (16HBE) cells poisoning model was deployed. Results showed that PM2.5 had a strong inhibitory effect on cells viability, and induced cells to secrete high levels of IL-6 and CXCL 8. These two biomarkers of inflammation were significantly reduced in the presence of TAK 242. TLR4, MyD88, IKK, and p-p65 proteins were highly expressed on exposure to PM2.5. Pretreatment with TAK 242 interfered with the activation of the TLR4 signaling pathway. By detecting the presence of lipopolysaccharides (LPS) in PM2.5 which had been autoclaved, it was speculated that the activation of the TLR4/NF-κB signaling pathway may be mediated by LPS. It was demonstrated using gain- and loss- function experiments that miR-140-5p negatively regulated TLR4 to mediate inflammation in 16HBE cells. The dual-luciferase reporter assay confirmed that miR-140-5p directly binds to the 3' untranslated region (3' UTR) of TLR4 to initiate biological activity. In conclusion, this study revealed a new mechanism by which the miR-140-5p/TLR4 signaling pathway mediated the inflammatory response of 16HBE cells induced by PM2.5. Differential expression of miRNA, and the activation of the TLR4/NF-κB signaling pathway induced by PM2.5 implicates PM2.5 in the pathogenesis of airway inflammation.

Risks related to heavy metal pollution in urban construction dust fall of fast-developing Chinese cities.

Urban construction is a major contributor to air pollution, but few studies have examined heavy metal pollution in urban areas caused by construction dust fall. We measured the concentrations of Cr, Ni, Cu, Zn, Pb, Cd, and Hg and particle size distribution in dust fall from various construction activities in seven fast-developing cities in China and conducted a health risk assessment. Mean metal concentrations in construction dust fall were on the order of Zn (246.3 mg/kg) > Cr (94.2 mg/kg) > Pb (56.5 mg/kg) > Cu (53.6 mg/kg) > Ni (22.8 mg/kg) > Cd (0.68 mg/kg) > Hg (0.08 mg/kg). Cu and Zn were positively correlated in areas of subway and building construction, and Pb and Cd were positively correlated in areas of road construction, likely because of the materials specific to these activities. Enrichment factors for heavy metals at all sampling sites were on the order of Cd (10.4) > Zn (6.37) > Cu (4.25) > Pb (3.84) > Hg (2.41) > Cr (2.02) > Ni (1.32). The enrichment factors for all metals except Zn indicated that heavy metal pollution was highest in road construction, followed by building and subway construction. Non-carcinogenic risks to children (hazard index >1) were 1.01-1.08 in four of the seven sampling sites, indicating possible risk from deposition of construction dust fall. In contrast, the hazard index for adults was <1 at the seven cities and total carcinogenic risks (<1 × 10-6) were at acceptable levels. An integrated ecological risk assessment demonstrated that heavy metal particles in construction dust fall in two of the cities (Shijiazhuang and Qingdao) were likely to be suspended in the atmosphere. Our study of heavy metal pollution in construction dust fall provides data on ecological and human health impacts and suggests that extensive measures are required to control construction dust fall in China.

A geochemical analogy between the metal sources in Kuwait Bay and territorial sea water of Kuwait.

The sea water serves as a source for desalination and shelter for dependent biota. To understand the sources of metal in Kuwait Bay and the open sea, samples were collected and analyzed for metals like B, Li, Sr, Hg, Pb, Ba, Fe, Zn, Mn, Be, Cd, Co, Cr, Ni, Se, V, Al, Mo, and As. The comparison of Bay and Seawater shows that most of the metals were higher in sea water. Samples were collected in two different transects in the territorial sea water (TSW), the northern, and the southern transects. The heavy metal evaluation index and degree of contamination calculated for Bay and TSW show that they are contaminated, and the degree was higher in TSW. The variation of metal concentration along the transects in TSW reflects three different behaviors; (1) few metals decrease from the shore, (2) few increases from the shore, and (3) others show no significant trend. The statistical analysis of the data shows a representation of five factors for bay water and six for TSW indicating the complexity in sources of metal in TSW. The analysis infers the metal contamination due to petroleum products, and oxidation-reduction cycles are predominant in TSW. But, tidal influence along with dustfall plays a key role in the metal contamination of bay waters. Apart from these, desalination rejects and domestic sewage effluents are common sources contributing metals to both the environment. It is also observed that the suspended sediments play a significant role in the leaching, adsorption, and distribution of metals. The extraneous process has a predominant control over the distribution of the metals in TSW than the Bay.

A simple lead dust fall method predicts children's blood lead level: New evidence from Australia.

We have measured dust fall accumulation in petri dishes (PDD) collected 6 monthly from inside residences in Sydney urban area, New South Wales, Australia as part of a 5-year longitudinal study to determine environmental associations, including soil. with blood lead (PbB) levels. The Pb loading in the dishes (n = 706) had geometric means (GM) of 24µg/m2/30d, a median value of 22µg/m2/30d with a range from 0.2 to 11,390µg/m2/30d. Observed geometric mean PbB was 2.4µg/dL at ages 2-3 years. Regression analyses showed a statistically significant relationship between predicted PbB and PDD. The predicted PbB values from dust in our study are consistent with similar analyses from the US in which floor dust was collected by wipes. Predicted PbB values from PDD indicate that an increase in PDD of about 100µg/m2/30d would increase PbB by about 1.5µg/dL or a doubling PbB at the low levels currently observed in many countries. Predicted PbB values from soil indicate that a change from 0 to 1000mg Pb/kg results in an increase of 1.7µg/dL in PbB, consistent with earlier investigations. Blood Pb levels can be predicted from dust fall accumulation (and soil) in cases where blood sampling is not always possible, especially in young children. Petri dish loading data could provide an alternative or complementary "action level" at about 100µg Pb/m2/30 days, similar to the suggested level of about 110µg Pb/m2 for surface wipes, for use in monitoring activities such as housing rehabilitation, demolition or soil resuspension.

[Pollution Characteristics of Carbonaceous Components in PM10 and PM2.5 of Road Dust Fall and Soil Dust in Xi'an].

To investigate the pollution characteristics of carbonaceous components in PM10 and PM2.5 of road dust fall and soil dust in Xi'an and enrich their source profiles, samples from five sites of road dust fall and 16 sites of soil dust were collected in Xi'an from April to May 2015. The ZDA-CY01 particulate matter resuspension sampler was used to obtain PM10 and PM2.5 samples, and the Model5L-NDIR OC and EC analyzer were used to determine the concentrations of organic carbon (OC) and elemental carbon (EC) in PM10 and PM2.5. The pollution and sources of carbonaceous aerosol in PM10 and PM2.5 were investigated by analyzing OC and EC characteristics, ratio, and the principal component analysis statistical model. The results showed that the proportions of OC in PM10 and PM2.5 at the various dust fall sites differed, ranging from 6.0% to 19.4% and 7.6% to 29.8%, respectively. The ratios of EC in PM10 and PM2.5at the different dust fall sites were relatively small, accounting for 0.6%-2.2% and 0.2%-3.6% in urban sites, respectively; however, EC was almost undetectable in most peripheral soil dust. The proportions of carbonaceous components in PM10 and PM2.5 followed the order of urban road dust fall>external control dust>river beach soil dust>soil dust and urban road dust fall>soil dust>external control dust>river beach soil dust, respectively. OC dominated the carbonaceous aerosols at the different sites, which was relatively low in urban road dust fall. The OC to total carbon (TC) ratios in PM10 and PM2.5 at urban road dust fall were 85.2%-95.3% and 87.9%-98.9%, respectively. The OC to TC ratios in PM10 and PM2.5 of soil dust were relatively high, exceeding 99%. Carbonaceous components were primarily concentrated in fine particles. The pollution distribution of carbonaceous components in the urban road dust fall sites was consistent, whereas that in the different soil dust sites were quite different. The carbonaceous components in urban road dust fall and soil dust were primarily affected by pollutant source emissions such as biomass burning, coal burning, gasoline, and diesel vehicle exhaust. There were differences in the source contribution rates of carbonaceous aerosols in PM10 and PM2.5.

[Risk Assessment of Heavy Metals in Dust Fall Around Reservoirs in Typical Ecologically Fragile Areas and Traceability Based on APCS-MLR Model].

To assess the health risk status and pollution sources of heavy metals in the atmosphere of ecologically vulnerable areas, the surrounding area of Dahekou Reservoir in Xilingol League was selected as the study area. From 2021 to 2022, 12 monitoring points for atmospheric dust fall were collected for a period of one year. A total of 144 samples were collected to determine the contents of eight types of heavy metals, namely Cr, Ni, Pb, Cu, Zn, Mn, As, and Cd. The potential ecological index (Eri) and health risk assessment model were used to assess the risk level of atmospheric heavy metals on ecological security and human health. The analysis of enrichment factors, principal components, and the model of absolute principal component multiple linear regression (APCS-MLR) receptor were used to analyze the sources of heavy metal pollution qualitatively in the atmosphere of the study area. The results showed that:① the mean value of the comprehensive potential ecological risk of heavy metals in the annual atmospheric dust fall in the study area was at a high ecological risk, and only the Cd value was at a very high risk level among the heavy metals, whereas the remaining were at a slight risk. ② The results of the health risk showed that intake by hand, mouth, and skin contact were the main exposure routes, which led to non-carcinogenic and carcinogenic risks. Children were under non-carcinogenic and acceptable carcinogenic risks in different months. During those months, the main source of the risks was As. ③ Through enrichment factor analysis, principal component analysis, and APCS-MLR receptor model calculation, the results revealed that the proportion of wind-blown sources was the largest, accounting for 37.82%, and the contribution rates of coal combustion and traffic sources to Cu, Cd, Pb, and Zn were 73.01%, 40.22%, 70.31%, and 32.82%, respectively. The contribution rate of mining activities to As was 42.59%, while that of industrial sources of Cd was 22.01%; the contributions of other human activity sources of Cd, As, Pb, and Zn were 21.12%, 34.40%, 23.04%, and 32.15%, respectively.

[Characteristics of Atmospheric Dust Fall Pollution and Its Chemical Composition and Mass Reconstruction in Mentougou District of Beijing].

To study the characteristics of atmospheric dust fall pollution in Mentougou District of Beijing, the monthly average monitoring results of 57 atmospheric dust fall samples from two state-controlled ambient air stations in Mentougou District from 2018 to 2022 were collected, and the atmospheric dust fall pollution status and its time variation characteristics in Mentougou District were analyzed. In order to explore the characteristics of chemical components of atmospheric dust fall and the results of quality mass reconstruction and their sources, 57 dust fall samples were collected using the active suction method at the Sanjiadian State-controlled Ambient Air Station. The mass concentration of dust fall and its chemical components were measured, the characteristics of chemical components in atmospheric dust fall were studied, and the mass reconstruction of the main components of atmospheric dust fall was performed using particle mass reconstruction technology. The reliability of the mass reconstruction results and the reasons for its undetermined components were also discussed. The results showed that from 2018 to 2022, the monthly dust fall in Mentougou District of Beijing changed periodically, being the maximum in April or May in spring and the minimum in October or November in autumn, and the maximum monthly dust fall was 3.2 to 8.4 times the minimum monthly dust fall. The order of the quarterly average monthly dust fall was as follows:spring>summer>autumn>winter, and the dust fall mainly came from spring and summer, accounting for 40.1%-43.0% and 23.8%-37.5% of the total annual dust fall, respectively. The annual average monthly dust fall in Mentougou District of Beijing showed a significant downward trend. The dust fall in 2022 had decreased by 52.8% compared with that in 2018, with an average annual decline of 13.2%, which was related to the improvement in the fine management level of urban environmental protection in Beijing in recent years. In 2021, soil dust had a significant impact on dust fall in Mentougou District, with an actual contribution of 44.2%. The chemical components in the atmospheric dust fall in Mentougou District were mainly water-soluble ions, crustal elements, organic carbon(OC), and elemental carbon(EC). The total mass of the measured chemical components accounted for 65.0% of the mass fraction of the dust fall. The secondary organic carbon(SOC) was also an important component of the atmospheric dust fall, and its mass concentration was 13.5 µg·m-3, accounting for 96.4% of the mass fraction of OC. The main components of atmospheric dust fall mass reconstruction were crust element fugitive dust, organic matter(OM), SO42-, NO3-, NH4+, trace elements, EC, and Cl-, with mass concentrations of 34.8, 28.0, 20.6, 15.0, 5.6, 4.3, 3.2, and 2.2 µg·m-3, accounting for 25.5%, 20.6%, 15.1%, 11.1%, 4.1%, 3.2%, 2.3%, and 1.6% of the dust fall quality, respectively. The atmospheric dust fall mainly came from the soil dust, construction cement dust, biomass combustion, waste incineration, and secondary transformation process. The measured mass concentration of atmospheric dust fall had a good correlation with the reconstructed mass concentration of chemical components, and the determination coefficient R2 was 0.8173. The undetermined components in the mass reconstruction results accounted for 16.5% of the dust fall mass, of which the particle bound water(PBW) in the dust fall accounted for 6.2% of the dust fall mass, and the remaining undetermined components might have been related to the unmeasured components, the selected estimation coefficient of OM and crustal elemental dust, the particle size composition, the selected chemical component analysis method, and its measurement error.

Characteristics and source analysis of potentially toxic elements pollution in atmospheric fallout around non-ferrous metal smelting slag sites-taking southwest China as an example.

More accurate source analysis of potentially toxic elements (PTEs) in atmospheric fallout that endanger biodiversity and human health remains needed. This study determined the concentrations of seven PTEs, including Pb, Cd, As, Cu, Zn, Ni, and Cr, by inductively coupled plasma mass spectrometry (ICP-MS), and the sources of PTE pollution were quantified using multivariate statistical analysis, including principal component analysis (PCA), cluster analysis (CA), and Pearson correlation analysis, and Moran index was applied for mutual verification and supplementation. PCA and CA revealed that the same mixed sources of Pb, Cd, As, Cu, and Zn were found in the atmospheric dust fall in the study area, while Ni and Cr had the same source of pollution. Pearson correlation analysis provided that there were strong correlations between Pb-Cd, Pb-As, Pb-Cu, Cd-As, Cd-Cu, As-Cu, and Ni-Cr, indicating commonality between the two sources of heavy metal pollution. Additionally, the Moran index showed that strong spatial correlations were observed between Pb, Cd, As, Cu, and Zn, whose sources were mainly related to non-ferrous metal processing smelter smelting slag sites and an environmental company in the study area. However, no spatial correlation was found between Ni and Cr, which mainly originated from the local geological background.

Heavy Metal Pollution Characteristics and Source Analysis in the Dust Fall on Buildings of Different Heights.

High-rise buildings block airflow, and dust accumulates on their upper surfaces. In this study, dust fall on the rooftops of low-, medium-, and high-rise buildings was sampled and analyzed to assess the degree of atmospheric heavy metal pollution. The Cr, Mn, Ni, Cu, Zn, As, Cd, and Pb mass fractions in dust samples were analyzed by microwave digestion/inductively coupled plasma-mass spectrometry. The average Cr, Ni, Cu, As, Cd, and Pb concentrations were highest on the rooftops of low-rise buildings, whereas those of Mn and Zn were highest on high-rise buildings. The cumulative indices for the eight heavy metals revealed a moderate pollution level for Zn on the rooftops of low- and high-rise buildings. Only the potential ecological risk index for Cd was very high, with a particularly high heavy metal-related ecological risk for low-rise buildings. The enrichment factor analysis and principal component analysis (PCA) demonstrated that Zn and Cd were strongly influenced by human activity. Zn, Cu, Cd, and Pb originated from traffic sources, Cr and Ni were derived from natural sources, and As was of industrial origin. The source analyses of rare earth elements were consistent with the heavy metal PCA results. In conclusion, our results provide a reference for hazard and source analysis of heavy metals in atmospheric dust fall on buildings of different heights.

Automated water recycle (AWR) method for dust removal from rooftop photovoltaic (PV) at Johor, Malaysia.

Abstract: Wet dust on the Photovoltaic (PV) surface is a persistent problem that is merely considered for rooftop based PV cleaning under a high humid climate like Malaysia. This paper proposes an Automated Water Recycle (AWR) method encompassing a water recycling unit for rooftop PV cleaning with the aim to enhance the electrical performance. This study makes a major contribution by developing a new model to correlate output power ( P out ) and dust-fall factor. For model validation, we conducted an experiment of taking one set of Monocrystalline PV (mono) on a 340 W m 2 of medium luminance day. One mono module was cleaned by AWR - pressurized water sprayed through 11 small holes over its front surface, while the other module was left with no-cleaning. The dust-contaminated water was filtered and collected back to the tank for recycling process. The water loss per cleaning cycle was achieved 0.32%, which was normalized to net loss of 28.8% at a frequency of 1 cycle/day for 90 days of operation. We observed that P out of no-cleaning PV was decreased by 29.44% than that of AWR method. From this experimental data also, a unique and more accurate model is created for P out prediction, which is much simpler compared to multivariables equation. Our investigation offers important insights into the accuracy of this regression model demonstrated by R 2 = 0.744 or a strong negative quadratic relationship between P out and dust-fall. The cleaning of PV modules is expected to save significant energy to reduce the payback period. Article Highlights: An automated water recycle method for cleaning dust-fall in rooftop photovoltaic module is proposed.Both simulation and experimental models are developed to predict output power of the photovoltaic module.Proposed method can produce 24.40% more output power than a no-cleaning system with a mere water loss of 0.32%/cycle.

Characterisation and Risk Assessment of Metal Contaminants in the Dust Fall in the Vicinity of a Construction Waste Dump in Beijing.

In this study, a large construction waste dump in Beijing, China, was used as the study area. Nineteen effective atmospheric dust samples were collected. The mass fractions of 14 metal elements (Ca, Fe, Al, Mg, Mn, Zn, Cr, Cu, V, Pb, Ni, As, Co, and Cd) were determined for the samples using ICP-MS. The pollutants and the potential ecological risk levels of 10 different heavy metals were evaluated using the enrichment factor, geo-accumulation index, and a potential ecological risk assessment method. The results showed that the Ca, Fe, Al, and Mg contents in the dust fall were considerably high and accounted for 98.81% of the total mass of the analysed metals. Cd and Zn were the main metal contaminants in the dust fall in the vicinity of the construction waste dump, followed by Cu and Mn. The Cd, Zn, Cu, and Mn contents in the construction waste had a significant impact on atmospheric pollution within 250 m of the dump. Moreover, Cd had the largest contribution to the comprehensive ecological risk posed by the heavy metals in the dust fall and was determined to be the primary ecological risk factor in the atmospheric environment in the vicinity of the construction waste dump.

Heavy metal pollution characteristics and health risk assessment of dust fall related to industrial activities in desert steppes.

China's desert steppe is the transition zone between the grasslands in central China and the arid desert. Ecological security in this region has long been a subject of debate, both in the local and academic communities. Heavy metals and other pollutants are readily released during industrial production, combustion, and transportation, aggravating the vulnerability of the desert steppes. To understand the impact of industrial activiteis on the heavy metal content of dust fall in the desert steppe, a total of 37 dust fall samples were collected over 90 days. An inductively-coupled plasma mass spectrometer (NexION 350X) was used to measure the concentration of heavy metals Cu, Cd, Cr, Pb, Mn, Co, and Zn in the dust. Using comprehensive pollution index and multivariate statistical analysis methods, we explored the characteristics and sources of heavy metal pollution. We also quantitatively assessed the carcinogenic risks of heavy metals resulting from dust reduction with the help of health risk assessment models. The heavy metals' comprehensive pollution index values in the study area's dust fall were ranked as follows: Zn > Cd > Pb > Mn > Cu > Co > Cr. Among these, Zn, Cd, and Pb were significant pollution factors in the study area, and were affected by industrial production and transportation. The high pollution index was concentrated in the north of the research industrial park and on both sides of a highway. The seven heavy metals' total non-carcinogenic risk index (HI) values were ranked as follows: Mn > Co > Pb > Zn > Cr > Cu > Cd (only the HI of Mn was greater than one). Excluding Mn, the non-carcinogenic and carcinogenic risk index values of the other six heavy metals were within acceptable ranges. Previous studies have also shown that industrial transportation and production have had a significant impact on the heavy metal content of dust fall in the desert steppe.

Differences of bacterial communities in different biological soil crusts around thermal power plant and their influencing factors.

To understand the effects of heavy metal pollution derived from atmospheric dust fall on bacterial community structure under different types of biological soil crusts near mining area, we measured the diversity, community composition, and relative abundance of bacteria communities in three different developmental stages of biological soil crusts (BSCs), including algae (ZB), mixed (HB), and moss (TB) crusts, and control (CK, bare soil) around a typical thermal power plant in Ningdong Energy Industrial Base, using the high-throughput sequencing technique. Environmental factors affecting the bacterial community structure were further investigated. The results showed that there were significant differences in physicochemical properties and heavy metal contents among different BSCs. The BSCs were heavily polluted due to the enrichment of heavy metals from atmospheric dust fall. Among the top ten dominant bacterial phyla, Gemmatimonadetes and Cyanobacteria were significantly distinct among different BSCs. Bacterial α diversity decreased in an order of CK>TB>HB>ZB. The NMDS ordination plots indicated that there were significant differences in the bacteria community composition of the three kinds of BSCs and the CK. The correlation analysis showed that the succession of BSCs significantly affected bacterial community composition in BSCs. Bacterial diversity and composition were closely related to pH, nutrients, and heavy metal contents. The relative abundance of Actinomycetes and Chloroflexi was positively correlated with pH, but negatively correlated with total N, total P, and the contents of heavy metal Pb, Zn, Cd. Results of the redundancy analysis showed that organic carbon, pH, total N, and total P were the major soil factors affecting bacterial α diversity, relative abundance of some dominant phyla, whereas heavy metal contents of Zn, Cd, Pb were the major heavy metals affecting structure of bacterial community which inhibited or stimulated the abundance and diversity of bacterial communities. We concluded that pH, heavy metals, and nutrients were the key factors affecting soil bacteria community composition. The succession of BSCs would improve their physicochemical properties and significantly impacted bacterial community composition. Long term heavy metals enrichment would affect bacterial diversity and community composition of BSCs.

Temporal and spatial variations of deposition and elemental composition of dust fall and its source identification around Tabriz, Iran.

Coarse particles are primarily deposited via sedimentation, commonly referred as dust fall (DF). This study presented the monthly and spatial variations of atmospheric DF and their elemental components (Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Se, Sr, Ti, V, Si, and Hg). Dust samples were collected from four urban and suburban sampling sites around Tabriz, Iran, by using the ASTM method D-1739 during April to September 2017. Moreover, the ICP-OES was used to determine metal components of the DF. The obtained results showed that the DF amount ranged between 1.8-27.6 (7.4 ± 5.6) g/m2.month. The elements of Fe (11863-13,906 mg/Kg and 85%-89%), Al (858-1205 mg/Kg and 4%-8%), and Si (274-386 mg/Kg) were the dominant elemental concentrations of the DF. The average value of enrichment factor (EF) for Hg, Pb, Cu, Sr, Co, Ni, Mn, and V was greater than 10 in all the samples, showing that anthropogenic sources emit a considerable amount of elements in DF rather than the soil or Urmia lake bed. The result of correlations between the concentration of dust fall with humidity, temperature, wind speed, and precipitation showed that there was a direct relationship between the amount of dust fall and wind speed while humidity, precipitation, and temperature were inversely proportional to the amount of dust fall. This study revealed that earth crust and anthropogenic activities such as vehicle traffic, combustion of fossil fuel, and different industrial activities were the main sources of the DF in the studied areas.

A Qualitative Study of Airborne Minerals and Associated Organic Compounds in Southeast of Cairo, Egypt.

This study is concerned with the identification of the mineralogical composition of dust fall samples collected from southeast of Cairo, Egypt. The mineralogical identification was conducted by means of the polarizing microscope, infra-red spectroscopy (IR), and X-ray diffraction (XRD). The relationship between the mineralogical composition of dust fall samples and 10 rock samples from the surrounding terrains were investigated. The major mineralogical species existing in the atmosphere of the study area are: carbonates mainly in the form of calcite in addition to the appearance of the dolomite form in traces overall the study area, but with considerable observation in the southern region; quartz which is less than calcite in its abundance; sulphates in the form of gypsum which may also be present as traces in the anhydrite form. Trace constitution of feldspars; clay minerals in the form of kaolinite, illite, and montimorillonite; and halite are also observable in the same samples. Organic compounds are present in the atmosphere of the area mainly as alkanes with presence of traces of phosphines. This study qualitatively shows the mineralogy of air particulate over rock processing area and the obtained results indicates that the main pollution source in the study area is the industrial activities with minor contribution of the natural sources, especially erosion and dust carried by winds from the surrounding terrains Cairo in the southern direction. This study provides useful results for the contribution of rock processing activities to the mineral composition of atmospheric particulates.

[Characteristics of Elements in PM2.5 and PM10 in Road Dust Fall During Spring in Tianjin].

To explore the element pollution characteristics and sources of road dust fall, road dust fall samples were collected during spring in Tianjin and suspended to obtain PM2.5 and PM10, 16 elements were analyzed, and then their characteristics, sources, and similarities were studied by nonparametric tests, the coefficient of divergence, and enrichment factor. The results showed that the mass fraction (1%-20%) in sequential order of the elements in PM2.5 and PM10 in Tianjin road dust fall were Si > Al > Ca > Fe > Mg > K > Na. The coefficient of divergence of elements in PM10 and PM2.5 was 0.06, indicating that the elements profiles of PM10 might be similar to PM2.5. The elements of Cd and Cr in PM10 and PM2.5 were at a high level of enrichment degree, and Zn, Cu, Pb, and As showed significant enrichment. The main sources of the elements in PM10 and PM2.5 road dust fall in Tianjin were soil dust, construction dust, traffic dust (motor vehicle exhaust, tire wear, and brake wear), and coal combustion.

Source apportionment of settleable particles in an impacted urban and industrialized region in Brazil.

Settleable particulate matter (SPM), especially coarser particles with diameters greater than 10 µm, has been found culprit of high deposition rates in cities affected by hinterland industrial activities. This is the case of Metropolitan Region of Vitoria (MRV), Espirito Santo, Brazil where industrial facilities are located within the urban sprawl and building constructions are intense. Frequent population complaints to the environmental protection agency (IEMA) throughout the years have triggered monitoring campaigns to determine SPM deposition rates and source apportionment. Eight different locations were monitored throughout the MRV, and SPM was quantified and chemically characterized. Sources profiles were defined either by using US EPA SPECIATE data or by experimental analysis. Atmospheric fallout in the MRV ranged between 2 and 20g/(m2 30-day), with only one monitoring station ranging from 6-10 g/(m2 30-day). EC, OC, Fe, Al, and Si were found the main constituents of dry deposition in the region. Source apportionment by the chemical mass balance (CMB) model determined that steel and iron ore pelletizing industries were the main contributor to one of the eight locations whereas resuspension, civil construction, and vehicular sources were also very important contributors to the other stations. Quarries and soil were also considered expressive SPM sources, but at the city periphery. CMB model could differentiate contributions from six industrial source groups: thermoelectric; iron ore, pellet, and pellet furnaces; coal coke and coke oven; sintering, blast furnace, and basic oxygen furnace; and soil, resuspension, and vehicles. However, the CMB model was unable to differentiate between iron ore and pellet stockpiles which are present in both steel and iron ore pelletizing industries. Further characterization of source and SPM might be necessary to aid local authorities in decision-making regarding these two industrial sources.

[Characteristics and Sources of Elements in Atmospheric Dust Fall in Zhuzhou City, Central China].

To study the concentration characteristics as well as sources of elements and heavy metal pollution in atmospheric dust fall in Zhuzhou City, 144 samples from 12 sites in the Zhuzhou urban area were collected from January to December in 2012 and 28 kinds of elements in the samples were analyzed. The results showed that the dust fall quantities of the industrial areas and mixed commercial and residential (MCR) areas were, respectively, 89.46 g·m-2 and 33.20 g·m-2 and the range of all sample points was 23.14-114.67 g·m-2. There were 10 elements (Na, Mg, Al, K, Ca, Ti, Mn, Fe, Zn, Pb) in the industrial areas as well as 8 elements in the MCR areas, for which the contents greatly exceeded 1000 mg·m-1 in the atmospheric dust fall. The Zn and Pb contents exceeded 10000 mg·kg-1 in the dust fall of the industrial areas, which were far higher than those in the Earth's crust. The main sources of dust fall in Zhuzhou City were metal smelting, shallow ground dust, vehicle emissions, construction dust, and industrial production with specific elements (Mo, Ba). Correlation analysis, principal component analysis (PCA), and analysis of transportation characteristics showed that 13 elements (Mn, Fe, Co, Cu, Zn, As, Se, Ag, Cd, Sn, Sb, Tl, Pb) in dust fall mainly came from waste gas emissions of industrial areas in Zhuzhou, in which 7 heavy metal elements (Cu, Zn, As, Ag, Cd, Sb, Pb) caused serious pollution. The contents of heavy metals in the industrial areas were 7.4 to 4079.4 times the contents defined in China soil elements background values, whereas those in the MCR areas were 3.6 to 1413.4 times the soil background values. Cd was the highest background ratio element. The degree of contamination was clearly higher in the industrial areas than in the MCR areas.

[Assessment of Heavy Metals Pollution and Its Health Risk of Atmospheric Dust Fall from East Part of Junggar Basin in Xinjiang].

In order to evaluate the contamination and health risk of heavy metals from atmospheric dust fall in Zhundong opencast coalfield in Xinjiang, samples of atmospheric dust fall were collected from 52 sampling sites covering the entire region and the contents of Zn, Cu, Cr, Pb, Hg and As were tested and analyzed. The contamination was assessed by geo-accumulation index method, and the risk to human health was assessed using the US EPA Health Risk Assessment Model. The results showed that:The contamination of heavy metals from atmospheric dust fall had a significant difference, in the order of Zn > Cr > Cu > As > Pb > Hg, and the average contents were higher than the soil background of Changji. The coefficient of variation of Hg, Cu and As was 381.91%, 99.94% and 97.82%, and human activities had a greater impact on them. The correlation coefficients in 6 heavy metals were complex, the correlation coefficients among Zn-Cu-Cr were more relevant than Hg-As-Pb. The assessment results of geo-accumulation index indicated that the Zn pollution in the atmospheric dust fall should be classified as extreme degree, and that of Cu, Pb, As as between slight and extreme degrees, and Hg as practically uncontaminated. The exposure content of carcinogenic risk and non-carcinogenic risk of the study area had little difference. It was HQCr > HQAs > HQZn > HQPb > HQCu > HQHg, the total non-cancer hazard index was 0.258, the non-cancer hazard indexes were both lower than their threshold values, suggesting that they would not harm the health. The carcinogenic risk hazard indexes were in the order of CRAs > CRCr > CRPb, suggesting that Pb had no cancer risk, while As was the most important carcinogenic factor. The average TCR was 1.95E-05, indicating that the risk was within the limit that human can tolerate.

Perchlorate in dust fall and indoor dust in Malta: An effect of fireworks.

We report on the presence of perchlorate in the settleable dust of Malta, a small central Mediterranean island. Both dust fall collected directly as it precipitated from atmosphere over a period of one month and deposited indoor dust from domestic residences were studied. Perchlorate was determined by ion chromatography of water extracts of the collected dusts. Dust fall was collected from 43 towns during 2011 to 2013 and indoor dust was sampled from homes in the same localities. Perchlorate was detected in 108 of 153 samples of dust fall (71%) and in 28 of 37 indoor dust samples (76%). Detectable perchlorate in dust fall ranged from 0.52µgg(-1) to 561µgg(-1) with a median value of 6.2µgg(-1); in indoor dust, levels were from 0.79µgg(-1) to 53µgg(-1) with a median value of 7.8µgg(-1), the highest recorded anywhere to date. Statistical analysis suggested that there was no significant difference in perchlorate content of indoor dust and dust fall. Perchlorate levels in dust fall escalate during the summer in response to numerous religious feasts celebrated with fireworks and perchlorate persists at low µgg(-1) concentrations for several months beyond the summer festive period. In Malta, perchlorate derives exclusively from KClO4, imported for fireworks manufacture. Its residue in dust presents an exposure risk to the population, especially via ingestion by hand to mouth transfer. Our results suggest that wherever intensive burning of fireworks takes place, the environmental impact may be much longer lived than realised, mainly due to re-suspension and deposition of contaminated settled dust in the urban environment.