Prediction of dust fall concentrations in urban atmospheric environment through support vector regression

Support vector regression （SVR） method is a novel type of learning machine algorithms, which is seldom applied to the development of urban atmospheric quality models under multiple socio-economic factors. This study presents four SVR models by selecting linear, radial basis, spline, and polynomial functions as kernels, respectively for the prediction of urban dust fall levels. The inputs of the models are identified as industrial coal consumption, population density, traffic flow coefficient, and shopping density coefficient. The training and testing results show that the SVR model with radial basis kernel performs better than the other three both in the training and testing processes. In addition, a number of scenario analyses reveal that the most suitable parameters （insensitive loss function e, the parameter to reduce the influence of error C, and discrete level or average distribution of parameters σ） are 0.001, 0.5, and 2 000, respectively.

Quantitative estimation of dust fall and smoke particles in Quetta Valley

Tightening of air quality standards for populated urban areas has led to increasing attention to assessment of air quality management areas, where violation of air quality standards occurs, and development of control strategies to eliminate such vio-lation of air quality standards. The Quetta urban area is very densely built and has heavy motorized traffic. The increase of emis-sions mainly from traffic and industry are responsible for the increase in atmospheric pollution levels during the last years. The dust examined in the current study was collected by both deposit gauge and Petri dish methods at various sites of Quetta Valley. Smoke particles were obtained by bladder method from the exhausts of various types of motor vehicles. The concentration of lead found in the smoke ranged from 1.5×10?6 to 4.5×10?6.

A Study of Heavy Metals in the Dust Fall around Assiut Fertilizer Plant

A study of an environmental assessment of dust fall and the associated heavy metal contents was conducted during the period from the first of March 2011 to the end of February 2012 at adjoining area of a phosphate fertilizer plant. Around the industrial area 8 dust fall stations were established and one of them was built upwind far from pollution activities to be taken as a control sample. Dust fall samples collected monthly weighed and then prepared to be analyzed through Inductively Coupled Plasma-Mass Spectroscopy (ICP-MS) to obtain heavy metal concentration. Meteorological parameters influencing the distribution of dust fall such as wind speed and direction, temperature, humidity, rain fall and pressure were determined. Results showed that deposition flow rates were 38.2. 47.5, 57.7, 44.3, 39.4, 38.2, 42.7 and 5.9 g/m2·month for the sites No., 1, 2, 3, 4, 5, 6, 7 and 8 respectively, and were compared with the findings of other investigators of like industrial areas worldwide. Levels of heavy metal As, Cu, Pb, Zn, Cd, and Hg in the deposited dust fall were 3.30, 26.46, 22.33, 235.00, 4.53 and 3.80 μg/g respectively. Enrichment coefficients of the heavy metals in the dust fall were found to be significant and reached the values 1.81, 0.90, 0.85, 0.65, 0.41 and 0.35 for zinc, lead, cadmium, copper, mercury and arsenic respectively. The paper ends with results and recommendations suggesting a methodology to remediate the investigated area polluted with heavy metals and control measures for the fertilizer plant to reduce pollution into the surrounding environment.

Geochemical Characteristics and Pollution Source Identification of the Near-surface Atmosphere Dust-fall in Jining City,Eastern China

Samples of near-surface atmosphere dust-fall and different pollution end-members were collected in the urban area of Jining City. The element characteristics of the near-surface atmosphere dust-fall and pollution end-members were analyzed systematically and the spatial distribution of the dust-fall and its pollution sources were studied. The results showed that the contents of elements varied obviously in different pollution end-members. The contents of As,Cd,Cu,F,Pb,S and Se within coal dust-fall were the highest,higher than those in atmosphere dust-fall and had great influences on the environment. The contents of Cd,Pb,Se,Zn,Hg and CaO within near-surface atmosphere dust-fall were affected by human activities to different degrees. Results of correlation analysis and factor analysis showed that Cd,Pb,Se and Zn mainly came from enterprise coal consumption,with a contribution ratio of 26. 32%. The contents of the above four elements near chemical factories,steel factories and high populated regions were generally high,which was consistent with the spatial distribution of the coal pollution sources.CaO was related to traffic pollution,with a contribution ratio of 10. 06%. Hg was mainly due to automobile emissions,with a contribution ratio of 8. 12%. The contents of As,Cr,F and Ni within dust-fall were seldom influenced by human activities and mainly came from soil sedimentation( natural sources),with a contribution ratio of 30%. The above four pollution sources( enterprise coal consumption,traffic pollution,automobile emissions and soil sedimentation) were the main sources of atmosphere dust-fall in Jining City. The enrichment coefficients of As,Cr,F and Ni were smaller and the spatial correlations of the four elements were better,while the enrichment coefficients and variable coefficients of elements influenced by human activities,such as Cd,Pb,Se and Hg were larger,and the spatial distributions of these elements were consistent with those of the pollution sources.

Effects of Dust on Male and Female Floral Organs and the Pollination of the Walnut

The Tarim Basin,Xinjiang,China,a region important to the walnut industry,is affected by frequent heavy dust storms.Dust,including micro-particles(diameter<10μm),covers the surface of the walnut tree,thereby changing the surface-atmosphere interface microenvironment,which,in turn,influences the exterior and interior structure of the tree.Dust storms occur in spring and summer,during the flowering period of walnut,which is the key developmental stage leading to fruit formation.This study investigated the effects of dust on female flowers,male flowers,and the pollination of walnut.The morphological changes in the stigma during pollination were recorded.Stigma receptivity was studied via the benzidine–H2O2 method.Morphological features of the female floral organs and pollen were investigated using scanning electron microscopy.Pollen germination and pollen tube growth were examined by fluorescence microscopy.The results showed that dust had a significant inhibitory effect on male and female flowers,resulting in decreased catkin growth,reduced pollen viability(pollen viability was 20.13%),blocked pollen apertures,a reduced pollen germination rate on the stigma,and increased time needed for pollen tube appearance.Dust also had an inhibitory effect on stigma length and receptivity of female walnut flowers,with the length of the walnut stigma being reduced by 0.25~0.80 mm during the flowering process.In addition,there was decreased stigma mucus,resulting in stigma atrophy,decreased amount of pollen on the stigma,weakened stigma receptivity,and accelerated drying of female flowers.In the Tarim Basin,walnut flowering occurd at the same time as dust storms do,which had a negative impact on the floral organ,flowering and pollination of walnut.

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.

Interannual Variation Characteristics of the Atmospheric Dust Deposition on Typical Region of Chaihe Basin

[Objective]The aim was to study the interannual changes of atmospheric dust deposition and quantity of combustible dust-fall in Chaihe basin.[Method]Taking Chaihe Basin in south Dianchi as study area,the atmospheric dust deposition and combustible substances in the residential,chemical area,sand production area and watershed in Chaihe basin were measured.The pollution and interannual changes of atmospheric dust in Chaihe basin were discussed.[Result]In the residential,chemical area,sand production area and watershed,the amount of sand was the highest in sand production area and lowest in the watershed.While the dust amount in the chemical area and watershed areas were lower than sand production area and higher than watershed area.In the four chosen areas,the highest value of dust appeared in autumn and the lowest value appeared in precipitation season.Sand in other months changed and the change scale was large,which indicated that the meteorological condition had large influences on dust.Relevance analysis indicated that the dust in sand production area showed positive relevance to flammable amount of dust.Dust and flammable amount had positive relevance.[Conclusion]The study provided theoretical basis for the atmospheric pollution situation in Chaihe Basin.

河南省2019—2021年城市大气降尘污染特征与影响因素识别

基于2019—2021年河南省城市大气降尘监测数据,分析了城市大气降尘污染变化,并利用趋势分析和相关系数法,识别了影响河南省城市大气降尘量的主要因素。结果表明,研究期间,全省年均城市大气降尘量的增幅为21%,78%的地市的大气降尘量呈上升态势。城市大气降尘量高值主要集中出现在多沙尘、少雨且多大风的3—6月,2021年还出现在了多强降水的7—9月。城市大气降尘量的增加受自然因素和人为因素共同作用:一方面,强降水的冲刷作用导致2021年7—9月城市大气降尘量高于历史同期;另一方面,河南省城市扬尘污染问题依旧突出,2021年城市大气PM10和PM2.5浓度比值比2019年增加了8%。因此,提升城市扬尘管理水平是减少城市大气降尘污染的重要途径之一。

大气降尘对土壤主要环境元素的累积影响及评价——以山东省高密市为例

为研究山东省高密市大气降尘主要环境元素的污染分布特征,探究其对表生环境中土壤的影响效应,对高密市大气降尘进行了系统采集、测试,取得了Cu、Pb、Zn、Ni、Cr、Cd、As、Hg、Se等9种环境元素测试数据,计算其年沉降通量、年增量,模拟了各元素达到限定值所需的最小年沉降通量,并对污染水平进行了评价。结果表明,大气降尘中各元素含量平均值均高于土壤背景值,表现为不同程度的富集。年沉降通量Cu与Pb呈显著正相关,Zn、Ni、Cr、Cd、As、Hg多呈现两两正相关,Se与其他元素相关性不显著,相关性越强则同源性越高。大气降尘是土壤主要环境元素的一个输入端元,其导致的表层土壤各元素年增速率为0.03%~0.52%,多年后Cd最接近土壤限定值。地累积指数评价显示,Ni、As、Cr为无污染至轻度污染,Se以重度污染为主,Cd、Zn为中度污染至重度污染,Hg、Cu、Pb以轻度污染至中度污染为主,污染程度排序为Se>Cd>Zn>Hg>Cu>Pb>Ni>As>Cr。

上海市降尘自动监测系统研发与应用

大气降尘量是重要的环境指标之一,可以较客观地反映和评价城市局部地区扬尘污染水平,对评价城市区域环境空气质量、分析大气污染来源和变化具有重要意义。国内外大气降尘监测普遍采用传统的手工监测方法,手工法因时效性差、效率低、能耗大、质控难、误差大等原因已不适应现代环境管理的需求。随着科技与网络的发展,自动监测方法成为发展趋势。文章主要阐述了上海市降尘自动监测技术的研发过程及实际应用,介绍了自主研发的降尘自动监测仪的原理、关键技术和系统组成。通过粉尘舱内实验、降尘自动监测方法与手工重量法比对测试及为期一年的试点应用,分析了降尘自动监测方法的精密度、准确度、相对误差及适用性,并探讨了降尘自动监测的应用前景。

安宁市大气降尘污染时空分布特征及来源分析

根据安宁市近4年(2019年12月~2023年11月)降尘监测数据,分析安宁市降尘污染的分布特征,旨在为安宁市的大气污染防控工作提供参考。结果表明,安宁市近4年的年均降尘量均低于昆明地区参考标准8 t/km2·m,且呈现下降趋势。降尘量最高的季节在春季,除第二年外,其余三年安宁市降尘量季节变化趋势均为春季>夏季>秋季>冬季,且降尘量的季节性差异不显著。安宁市大气降尘污染来源包括道路扬尘、施工工地扬尘以及工业企业废气扬尘等。

无锡市大气降尘时空分布特征浅析

以无锡市7个大气降尘监测点2021年1月—2024年2月的数据为基础,分析无锡市大气降尘时空分布特征。结果表明,2021—2023年期间,无锡市大气降尘量整体呈现波动下降趋势,具有明显的季节化特征,表现为春、夏季大气降尘量高于秋、冬季,月均大气降尘量的变化范围在2.3~3.5(t/月·km^(2))之间;大气降尘受人类活动、风速和城市扬尘的影响较大,并且和PM 10的污染来源具有一致性。

露天矿山爆破作业降尘技术研究进展

基于露天矿山爆破作业产尘高,治理难度大,对爆破作业粉尘危害现状和扩散规律进行介绍,针对现今降尘技术优缺点,对爆破降尘研究现状及分类进行综述。

鼠浪湖矿石码头皮带机系统环境治理的研究与应用

皮带机是一种常用的物料输送设备,广泛应用于矿石码头等场所,本文旨在探讨专业铁矿石码头皮带机系统扬尘治理的问题。首先对皮带机系统扬尘的特点进行分析,明确扬尘易发部位及其特点,其次指出传统除尘技术存在的问题,最后提出一套新的技术方案,并对其实施效果进行了阐述。

南京市不同功能区大气降尘的沉降通量及污染特征

选择南京市的钢铁工业区、工业与居民混合区、交通干道、居民生活区、风景区、城市郊区6种典型城市功能区，按月定期收集降尘，计算沉降通量．应用ICP-AES分析降尘中元素的含量，比较其化学组成和污染物特征．结果表明，研究期间南京市降尘沉降通量为3．39-65．95g／（m^2·月），工业区降尘通量显著高于其他区域，说明其局部来源的贡献超过了区域背景；不同功能区降尘中地壳元素绝对含量均较高，为主要的成分，而一些污染元素（Cu、Zn、Pb、Ni、As）的含量在工业混合区和钢铁工业区则相对较高．降尘中Ca、Cu、Zn、Pb的富集系数均〉10．北方远程来源的降尘对南京地区的影响很大，特别是对该地区的土壤“复钙”作用有很大的影响.

不同施工阶段扬尘污染特征研究

以北京城近郊区40多个建筑工地为实验工地,以降尘作为施工扬尘监测指标,对不同施工阶段的扬尘污染规律进行了研究,对不同施工阶段自身降尘浓度数据进行频率分布统计.结果表明,挖槽阶段相比结构和装修的施工扬尘污染更加严重;挖槽、装修和结构阶段自身降尘浓度>50 t/(km2.30 d)的概率分别为16%、16%和3%,挖槽和装修阶段比结构阶段更容易发生高强度施工扬尘污染;不同施工阶段都遵循春季施工扬尘污染强度明显大于夏、秋、冬季,以及冬季略大于夏、秋季的规律;不同施工阶段的扬尘污染强弱关系非常明显,扬尘污染强度比值为,挖槽∶结构∶装修等于100∶67∶87.

建筑工地大气降尘与总悬浮颗粒物相关性研究

通过统计大量实测数据,对北京市建筑工地施工扬尘大气污染指标DF与TSP的相关性进行了研究.结果表明,建筑施工扬尘所产生的DF与TSP有较好的线性关系,建筑工地边界处DF与TSP的关系可以用cTSP=11.6×cDF表示.监测点与污染源的距离对相关系数影响较大,相关系数与距离成正比例;施工阶段对相关系数影响较小.

施工扬尘空间扩散规律研究

通过检测建筑工地边界附近同一平面坐标1.5-4.1 m范围内不同高度处的降尘浓度变化，研究了建筑工地边界施工扬尘垂直扩散规律；通过监测建筑工地外同方向0-210 m范围内不同距离、相同高度（3 m）处的降尘浓度变化，研究了建筑工地施工扬尘水平扩散规律，通过数据回归分别得出了施工扬尘垂直、水平的扩散模型.结果表明，建筑工地边界同一平面坐标上方的施工降尘浓度与高度的2次方成反比关系，边界外部同一高度、同一方向的施工降尘浓度与监测点距工地中心距离的2次方成反比关系，施工活动和自然条件等因素主要影响垂直和水平扩散常数的大小.

济南市大气降尘地球化学特征及污染端元研究

在济南市城区对大气降尘及不同污染端元样品进行采集,系统分析了大气降尘和污染端元元素含量特征,并对大气降尘空间分布及污染来源进行研究.结果表明：不同污染端元中元素含量差别明显,燃煤尘中As、Cd、F、Pb是汽车尾气尘的3倍以上,是交通尘、冶炼尘、建筑尘等其他端元尘的1.26 ～ 2.35倍,对环境影响较大;汽车尾气尘中Cr、Ni、S、Zn含量最高,冶炼尘中Co、Ni、Pb、F含量偏高,而建筑尘中多数元素含量为所有端元尘中最低.与土壤背景值相比,济南市大气降尘中Cr、Cu、Pb、Zn、Cd、F、S富集程度较高,受到不同程度人为污染;相关分析和因子分析 结果表明,Cd、Cu、Hg、Pb、As主要来源于企业燃煤,大气降尘中这些元素高含量区与热电厂、冶炼厂、化工厂等燃煤污染源空间分布相一致;F、S可能与汽车尾气排放有关,而As、Cr主源于交通污染,这3种污染源是济南市大气降尘污染的主要来源,对降尘的贡献约占60.42％.研究表明,工业燃煤排放已逐渐代替汽车尾气成为大气降尘中Pb元素的主要来源.

道路扬尘评估方法的建立和比较

建立了降尘法和AP-42法2种道路扬尘评估方法,它们分别以减去背景降尘的道路自身降尘(ΔDFr)和道路扬尘排放强度(EIr)作为评估指标.通过对这2种方法评估结果的比较与分析发现:①ΔDFr和EIr有很好的正相关关系,相关系数(R2)为0.708;②ΔDFr能同时反映车辆激发扬尘和路面风蚀扬尘,而EIr只反映车辆激发扬尘;③积尘负荷大小不代表评估道路扬尘污染程度,但适用于定量评价道路清扫保洁质量.降尘法相比AP-42法,其实施安全、简单易行、误差小,但不能满足快速评估要求,而且评估成本略高.2种评估方法均表明《奥运保障措施》控制道路扬尘的效果明显,2008年北京奥运会期间与2007年同期相比,快速路、主干路、次干路和支路ΔDFr分别下降了65%,55%,65%和84%.