Toxicity Evaluation of Different Exposure Scenarios of Road Dust Using Daphnia magna and Artemia salina as Aquatic Organisms, and Prosopis cineraria and Vachellia tortilis as Native Plant Species

Particulate matter (PM10) deposited as road dust is considered an important source of contamination from atmosphere. However, there are limited studies on the toxicity of road dust as such on different organisms. This study evaluates the toxicity of road dust using different extraction scenarios on Daphnia magna and Artemia salina as aquatic organisms and also on Prosopis cineraria and Vachellia tortilis as local plant species. Chemical analysis of different extracts shows considerable amount of trace metals, however the trace metals in the dust extract associated with suspended sediment were not absorbed by the receptors. On the other hand, the concentration of trace metals in the artificial mixture was found bioavailable and absorbed causing a high percentage of mortality. In the plant assay, significant difference was obtained in the germination percentage between the control and three different extraction exposures in both plant species. The mean root length of P. cineraria and V. tortilis were higher in 20% and 50% extracts than the control probably due to the availability of nutrients from the dust extract. Interestingly however, the seedling vigor index was the opposite with higher index in the control and lower in dust extracts that contain heavy metals.

A Comprehensive Evaluation of State-of-the-Art Deep Learning Models for Road Surface Type Classification

In recent years,as intelligent transportation systems(ITS)such as autonomous driving and advanced driver-assistance systems have become more popular,there has been a rise in the need for different sources of traffic situation data.The classification of the road surface type,also known as the RST,is among the most essential of these situational data and can be utilized across the entirety of the ITS domain.Recently,the benefits of deep learning(DL)approaches for sensor-based RST classification have been demonstrated by automatic feature extraction without manual methods.The ability to extract important features is vital in making RST classification more accurate.This work investigates the most recent advances in DL algorithms for sensor-based RST classification and explores appropriate feature extraction models.We used different convolutional neural networks to understand the functional architecture better;we constructed an enhanced DL model called SE-ResNet,which uses residual connections and squeeze-and-excitation mod-ules to improve the classification performance.Comparative experiments with a publicly available benchmark dataset,the passive vehicular sensors dataset,have shown that SE-ResNet outperforms other state-of-the-art models.The proposed model achieved the highest accuracy of 98.41%and the highest F1-score of 98.19%when classifying surfaces into segments of dirt,cobblestone,or asphalt roads.Moreover,the proposed model significantly outperforms DL networks(CNN,LSTM,and CNN-LSTM).The proposed RE-ResNet achieved the classification accuracies of asphalt roads at 98.98,cobblestone roads at 97.02,and dirt roads at 99.56%,respectively.

Distribution of platinum group elements in road dust in the Beijing metropolitan area, China

Dust samples collected from the Beijing metropolitan area （China） were evaluated to determine the distribution and the concentration of platinum group elements （PGEs）. The dust particles that were smaller than 100 mesh size fraction （150 μm） were analyzed after aqua regia digestion. Concentrations ofPt, Rh, and Pd were found to be between 3.96 and 356.3 ng/g, 2.76 and 97.11 ng/g, and 0.1 and 124.9 ng/g, respectively, in the urban areas of Beijing, whereas for the background samples collected from the suburbs of Beijing, the concentrations of Pt, Pd, and Rh were very low and ranged from 0.1 to 0.9 ng/g, 0.5 to 1.4 ng/g, and 0.8 to 2.2 rig/g, respectively. The distributions of PGEs in road dust were an accurate reflection of the levels of pollution and were found to match with the local traffic conditions. A strong positive correlation was established among all the dements found in road dust. This suggests that emissions of abraded fragments from vehicle exhausts may be the source of the high concentration of Pt, Rh, and Pd in road dust along the main roads of Beijing.

The Pollution Character Analysis and Risk Assessment for Metals in Dust and PM_(10) around Road from China

INTRODUCTION In recent years, with the gradual improvement of road construction, the rapid increase of the number of motor vehicles, vehicle emissions and the current poor vehicle performance, poor vehicle maintenance, higher emission factor and so on, air pollution caused by the traffic issues becomes the focus of people attention. The harmful substances are gradually accumulated to atmosphere particles surrounding roads due to dust particles （soil dusts, road dusts, construction dusts）, coal emissions, industrial emissions, vehicle emissions, biomass burning, secondary particles, which has a certain harmful influence to the atmosphere, soil and plants surrounding roads.

Estimating emissions and concentrations of road dust aerosol over China using the GEOS-Chem model

Paved road dust is one of the most important aerosols in China. The authors estimated road dust emissions using an empirical model （AP-42 model） developed by the U.S. Environmental Protection Agency, and simulated road dust concentrations over China for the years 2006-2011 using the GEOS-Chem model.The annual road dust emissions amount averaged over 2006-2011 is estimated to be 2331.4 kt, with much higher emissions in eastern China than in western China. Because of heavy traffic and a dense road network, emissions are high over Beijing-Tianjin-Tanggu （BTT）, Henan Province, and Shandong Province. Meanwhile, emissions are calculated to be 459.1, 112.0, and 102.7 kt, respectively, over BTT, the Pearl River Delta （PRD） region, and the Yangtze River Delta （YRD）. Due to the monthly variation of precipitation, road dust emissions over China are simulated to be highest in December and lowest in June. The highest annual mean road dust concentration is simulated to be 14.5 tJg m-3 in Beijing. Over 2006-2011, because of the increases in road length and number of vehicles, annual road dust emissions for China as a whole, Bl-r, the PRD, and the YRD, are simulated to increase by 260%, 239%, 266%, and 59%, respectively, leading to 233%, 243%, 273%, and 100% increases in road dust concentrations in these regions, respectively. Our results have important implications for air pollution control in China.

Research Progress and Prospect of Road Dust Suppressants

Road dust has great adverse effects on traffic quality,traffic safety,atmospheric environment quality,and human health.Therefore,with the continuous development of modern science and technology,the research of road dust suppressants is also progressing.To promote the rational application and development of road dust suppressants,the research progress and prospects of them are analyzed in this paper.It includes a basic overview of road dust suppressants,the main types,the usage and precautions,and the main development direction.It is hoped that this analysis can provide some reference for further research and development of road dust suppressants.

Development and characterization of formulation of dust-suppressant used for stope road in open-pit mines

The components of dust-suppressant were determined based on the analysis on characteristics and mechanisms of road dust raising in open-pit mines. The components were initially selected from moisture agent, coagulation agent and surfactant. The optimal formulation was determined based on orthogonal test and using the water loss rate as the evaluation index. The performances of moisture releasing and adsorption, wind resistance of optimal formulation in the natural environment were tested. The results show that the formula obtained in experiments provide a good performance of moisture absorption and water retention, and it also had a good dust preventing and controlling performance due to its high surface strength and consolidation under dry conditions. It has good application prospects considering the wide variety of sources for materials and the simple preparation process.

Speciation of heavy metals in airborne particles,road dusts,and soils along expressways in China

This study analyzed the concentrations and chemical forms of Zn,Cu,Pb,Sb,Cd and Mn in airborne particles,road dusts and soils collected along three expressways in Jiangxi Province,China,with different traffic densities,and identified the levels and sources of heavy metal contamination.The concentrations of Zn,Cu,Pb,Sb,and Cd except Mn in airborne particles,road dusts and soils were all in direct proportion to traffic volume.Cd concentrations were low compared with other metals.For instance,the concentrations of Zn,Cu,Pb,Sb,Mn and Cd were 6.6,0.7,2.2,0.1,0.1 and 0.1μg·m-3in PM10along the Changjiu Expressway,792.8,241.4,248.3,9.6,340.5and 8.0 mg·kg-1in road dusts,and 201.1,143.2,59.5,9.5,338.9 and 2.3 mg·kg-1in soils,respectively,but in the case of the ratio of concentration to the environmental background value,most serious contamination was caused by Cd.The sources of the heavy metals were judged by comparisons of the chemical forms of the heavy metals in different environmental media.Pb and Mn in airborne particles were both derived from traffic;Pb in road dusts and soils resulted mainly from the use of leaded gasoline in the past;and Mn in road dusts and soils was derived from parent rocks.Zn,Cu,Sb and Cd in airborne particles,road dusts and soils were derived primarily from traffic,and differences in chemical forms of the heavy metals in different media were due to the interaction between heavy metals in airborne particles and organic matter and other surfaces in road dusts and soils.We also discussed the change of chemical forms of heavy metals in particles of different sizes and under different weather conditions.Bioavailability of heavy metals in airborne particles was much higher than that in road dusts and soils,especially Pb(0.676 in airborne particles,0.159 in road dusts and 0.095 in soils).

Measurement of Residual Volume in Patients with Pneumoconiosis and Workers Exposed to Cement Dust

The Residual Volume (RV) and Functional ResidualCapacity (FRC) were measured in 49 male workers exposedto cement dust (group A) and 50 male patients with pneu-moconiosis (group B). These data were compared withthose in 84 healthy workers (group C). Data from groupA, B exhibited mixed or obstructed ventilation dysfunction.The means of RV%, FRC% in group A were 31.2～35.6%and 56.7～59.3% respectively. These values were not onlysignificantly higher than those of the group C, but alsohigher than those of group B. The individual abnormaldetecting rates of RV% in group A, B were 26.5% and52.0% respectively, remarkably higher than 9.5% in thegroup C. It seems that RV% can be used as an individualscreening test in clinical practice. In physiologic terms,It has been recognized that FRC might more objectively.reflect the changes in quasi-static mechanics in community.The impact factors of RV might be related to quasi-staticmechanics other than to those of strength of respiratorymuscles, resistance of airway and collapsibility of bron-chial walls.

Assessment of Road Dust Contamination in India

The road dusts (RD) are fugitive in nature causing potential health hazards to people living in highways. They are generated from different sources on the roads and being a valuable archive of environmental information. In the present work, contamination assessment of 18 heavy metals and ions in road dusts of the country are described. Techniques i.e. ion selective, ion chromatography and atomic absorption spectrophotometers were used for analysis of the ions and metals. The content of F-, Cl-, , , , Na+, K+, Mg2+, Ca2+, As, Cr, Mn, Fe, Ni, Cu, Zn, Pb and Hg in the road dusts was ranged from 75 - 895, 276 - 12718, 48 - 1423, 243 - 10,580, 11 - 539, 290 - 46,484, 110 - 7716, 84 - 1771, 595 - 15,955, 24 - 42, 164 - 526, 1711 - 5218, 63,850 - 144,835, 47 - 62, 81 - 720, 166 - 450, 92 - 295 and 0.05 - 0.12 mg/kg with mean value of 224 ± 43, 3734 ± 895, 592 ± 895, 2859 ± 662, 143 ± 29, 4826 ± 2049, 1565 ± 411, 837 ± 121, 8545 ± 1288, 31 ± 4, 246 ± 82, 3002 ± 851, 91,331 ± 18,587, 54 ± 4, 206 ± 145, 241 ± 64, 171 ± 42 and 0.08 ± 0.02 mg/kg, respectively (at 95% probability). The enrichment, variation, correlation and sources of the contaminants are discussed.

Measurement of dust emission from a road construction using exposure-profiling method

Road construction is one example of heavy constructions that may have a substantial temporary impact on local air quality. Construction of Lule? Road during the summer of 2013 generated a great deal of dust emission. US EPA recommended exposure-profiling method was used to measure dust emission. Inexpensive BSNE dust samplers were used instead of high volume samplers. The objective was to give a general idea of the amount of dust generated due to the construction work. Dust generation related to weather was discussed under conditions. Estimated threshold wind velocities for road surface materials at the height of 2 m were 12.88 m/s, 12.88 m/s and 24.76 m/s which were lower measured wind velocities, indicating no dust generated from wind erosion. Dust masses for 7 sampling periods show dust generation had a close relation with moisture content of surface material. Wind speed, humidity had minor or no effect. The estimated dust emission rate in the construction work during the measuring period was 22.86 kg TSP/d, 6 kg/d was from construction work and 16.86 kg/d was generated due to traffic on temporary roads.

Influence of Traffic Volume on Fugitive Road Dust Emissions in Beijing, China

Eighty sites were set up to monitor road dust fall and 80 locations were selected to sample silt loading in April, August, and November 2007 and January 2008 in the Beijing metropolitan area. Fugitive road dust emission strengths were calculated using the AP-42 emission factor model. Silt loading on Beijing urban roads was typically less than 1.0 g/m^2, the PM10 emission strength was typically less than 100 kg/km·day, and road dust fall was typically less than 40 t/km^2·30day. The relationships between traffic volume, silt loading, fugitive road dust emission strength and road dust fall were studied in the Beijing metropolitan area. The results indicate that silt loading and emission factors are negatively correlated with traffic volume, but the PM10 emission rate and road dust-fall are positively correlated with traffic volume.

Analysis on emission factor of fugitive dust from road traffic

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Estimation of road dust using BSNEs

Mining is a core industry in Sweden and plays an important role in the economic development throughout the country. Though the importance of mining dust has been well recognized, the quantification of dust production with regard to individual source activity has rarely been done in Sweden. Depending on the type of source activity, dust estimation method can be chosen from three alternatives: exposure profiling methods, back calculation method, and wind erosion prediction method. Also included in the paper is an example of experiment, which was executed on two unpaved roads in Lulea, Sweden by using exposure profiling method. The experiment concluded that dust emission due to vehicle transportation is strongly dependent on traveling speed and road bed material.

风流扰动下露天矿土质路面粉尘运移规律研究

为降低露天矿土质路面粉尘质量浓度,提高清洁生产水平,采用气固两相流理论,建立粉尘颗粒起动模型,分析粉尘起动风速及变化规律,利用实验研究进行验证,并确立粉尘运移规律以及运动形式,选取正交实验极差分析各因素对起尘量影响显著性。研究结果表明:粉尘起动风速与粉尘粒径、含水率、负荷均有函数关系;起尘量在粒径、含水率、负荷、风速4种因素下呈现不同变化规律,与粒径、风速均呈非线性关系,与含水率呈负相关,与粉尘负荷呈正相关,影响显著性为:粒径>负荷>风速>含水率;粉尘运动形式与风速和粒径相关,在5 m/s风速下,(0,75]μm粒径粉尘易做悬浮运动,(75,500]μm粒径粉尘易做跳跃运动,(500,1000]μm粒径粉尘易做蠕移运动。研究结果可为降尘措施提供理论指导。

Elemental composition and risk assessment of heavy metals in the PM10 fractions of road dust and roadside soil

A total of 64 dust samples were analyzed to determine the size distribution and elemental composition of the PM10 fraction, including42 road dust(RD), 12 roadside soil(RSD), and 10 park road dust(PRD) samples. The mass of dust smaller than 20μm was dominated by particles sized 2.5-16 μm, which accounted for 85%, 88%, and 87% of the RD, PRD, and RSD, respectively. Additionally, crustal elements accounted for 30.14%, 36.35%, and 37.14% of the PMio fractions of the RD, RSD, and PRD, respectively. The most abundant trace elements in RD, RSD, and PRD were Zn, Mn, and Cu (range, 277 to 874 mg/kg). Moreover, the /geo values revealed all dusts were contaminated with Pb, Zn, Cu, Sb, Sn, and Cd. Health risk assessment showed that Mn, Ni, Cu, Zn, Cd, Sb, and Pb in the PM10 fraction of three types of dusts posed non-cancer risks to children but posed no non-cancer risk to adults. Additionally, As, Ni, and Cd posed no cancer risk to inhabitants.

Application of micro-morphology in the physical characterization of urban road dust

Urban road dust was collected from Vellore City,Tamil Nadu,India,and analyzed.Scanning electron microscopy(SEM)was used to examine road dust from nine sampling locations in the study region.SEM image analysis was used to identify various shape factors of collected dust particles.The equivalent spherical diameter of most particles was between 10μm and 30μm.Fine particles had greater concentrations at locations with higher traffic flow.Particles were categorized into four classes based on their shape factors,viz.,spherical,mineral,elongated,or irregular.Spherical particles had the smallest mean equivalent diameter(1.95μm)and mineral particles had the largest diameter(33.3μm).Spherical particles made up the smallest portion of road dust(0-12%)in the study region and mineral particles made up the largest(45-65%).Elongated and irregular particles,each made up 23-30%of road dust.Electron dispersive X-ray spectroscopy analysis was used to identify the elemental composition of dust particles.Spherical particles were mostly from combustion sources and mineral particles were largely of crustal origin.No individual source was found for irregular and elongated particles.Biological debris was the major source of irregular particles.

秸秆基新型道路抑尘剂的制备与应用

以玉米秸秆为主要原料,以复合酶(木聚糖酶、β-葡聚糖酶、纤维素酶与羧甲基纤维素钠(CMC))、淀粉、Na_(2)CO_(3)为辅料,制备了一种道路抑尘剂,采用响应面分析法优化了制备工艺,并考察了该抑尘剂对大气中PM_(2.5)和PM_(10)的去除效果。实验结果表明:4种酶对抑尘剂失水率的影响顺序为β-葡聚糖酶>木聚糖酶>CMC>纤维素酶;在木聚糖酶、β-葡聚糖酶、纤维素酶与CMC质量比2.5∶1∶15∶23.5、反应温度45℃、反应pH 4.75、淀粉与复合酶质量比1.8∶1的最佳条件下,所制得抑尘剂的黏度为48 mPa·s、表面张力为0.02 N/m、密度为1028 kg/m^(3)、失水率为2.17%;喷洒该抑尘剂后,大气中PM_(2.5)的质量浓度从75.74~114.83 mg/m^(3)降低至0.34~0.91 mg/m^(3),PM_(10)的质量浓度从49.94~74.57 mg/m^(3)降低至0.12~0.34 mg/m^(3),去除率均大于99%。

钛冶金氯化收尘渣钒资源回收利用研究

对某钛冶金氯化收尘渣进行水洗无害化处理得到水洗渣;对水洗渣进行钙化焙烧,研究了焙烧温度和焙烧时间对水洗渣钒浸出率的影响。结果表明,氯化收尘渣中钒主要以低价钒形式存在;钒浸出率随焙烧温度升高而增加,焙烧温度850℃时,钒浸出率达88%;焙烧时间增加,不同产物进行二次反应,形成钒青铜等难溶化合物,出现不同价态钒酸盐相,导致在Na_(2)CO_(3)溶液中钒浸出率不同;适宜的焙烧温度为850℃,焙烧时间为120 min。