黑河流域中游荒漠区沙尘暴、扬沙和浮尘与气候因子的关系

[目的]分析黑河流域中游荒漠区沙尘暴、扬沙和浮尘频次和时长的月变化和年变化及其成因,并分析其与主要气候因子的关系,为区域沙尘天气的早期预警和荒漠区的经营和管理提供依据。[方法]利用黑河流域红沙窝荒漠化综合防治试验站的2010—2019年的沙尘天气监测数据和气象数据进行分析。[结果]沙尘频次和时长主要集中在春季,其次是冬季,春冬两季的频次和时长各占全年的82.3%和79.4%。10 a间沙尘暴和扬沙频次总体变化趋势逐渐减少,而浮尘频次总体变化趋势逐年增加;沙尘时长总体变化趋势逐年增加。沙尘频次月变化与土壤湿度(10 cm)和大气湿度之间呈极显著负相关(p0.01),与风速之间呈极显著正相关(p0.01)。春季期间,沙尘暴年际发生频次仅与土壤湿度(10 cm)之间呈极显著负相关(p0.01),扬沙年际发生频次仅与土壤湿度(10 cm)之间呈显著负相关(p0.05),浮尘年际发生频次与土壤温度(5 cm)之间呈显著正相关(p0.05);冬季期间,沙尘暴年际发生频次与土壤温度(5 cm)之间呈显著负相关(p0.05),与土壤湿度(10 cm)和降水量之间呈极显著负相关(p0.01);扬沙年际发生频次与土壤温度(5 cm)之间呈显著负相关(p0.05),与大气温度之间呈极显著负相关(p0.01)。[结论]近10 a来,黑河流域中游荒漠区的沙尘天气主要发生在春季和冬季,破坏性较大的沙尘暴和扬沙逐年减少,而浮尘逐年增加。沙尘频次的月变化主要影响因素是浅层土壤湿度、大气湿度和风速。春季的浅层土壤湿度影响了沙尘暴和扬沙年际频次变化,浅层土壤温度影响了浮尘年际频次变化;冬季的浅层土壤温湿度和降水量影响了沙尘暴的年际频次变化,浅层土壤温度和大气温度影响了扬沙的年际频次变化。     

河北省沙尘天气时空分布特征及影响因素分析

利用20个基础气象站1980-2006年的气象观测数据,对河北省沙尘天气的时空分布特征及其影响因素进行了分析研究.结果表明,河北省沙尘天气以扬沙为主;在空间分异上,沙尘天气自西向东发生频次递减,西北部和南部是沙尘天气的高发区,东部是沙尘天气的低发区,各类沙尘天气的高发中心不尽相同.在年际变化上,扬沙、浮尘和沙尘暴3类沙尘天气均呈逐年波动减少的趋势,春季发生次数最多;气候周期性变化是造成沙尘天气年际年内变化的主要原因,大风与沙尘源地的耦合决定了沙尘天气的空间分布特征.     

太行山南麓不同植被类型土壤呼吸特征及其温度敏感性

[目的] 探讨不同植被类型土壤呼吸特征及其温度敏感性,为陆地生态系统碳循环研究提供理论支持。[方法] 以太行山南麓裸地、草地、灌丛、林地为研究对象,采用长期定位观测和室内化验分析相结合的方法,研究不同季节土壤水热因素、呼吸特征及其温度敏感性。[结果] 不同植被类型的土壤温度变化较大,均表现为1月初最低,8月下旬最高,8月以后土壤温度呈逐渐降低模式,相同月份土壤温度大致表现为：裸地>草地>灌丛>林地,局部有所波动。不同植被类型的土壤呼吸速率具有明显差异,季节变化特征一致;其中,土壤呼吸、异养呼吸和自养呼吸速率季节变化特征一致（倒V形变化规律）,大致表现为：夏季 > 秋季 > 春季 > 冬季。不同植被类型的土壤呼吸湿度敏感性大致表现为：裸地 < 草地 < 灌丛 < 林地。由此说明植被类型是影响土壤呼吸温度敏感性的重要因素,并且夏季和秋季土壤呼吸Q₁₀显著高于春季和冬季。相关性分析表明土壤pH值与温度敏感性（Q₁₀）呈显著负相关（p<0.05）,与有机碳含量呈显著正相关（p<0.05）。不同植被类型土壤异养呼吸夏季的贡献率最高,春季的贡献率最低,贡献率依次表现为：夏季>秋季>冬季>春季,自养呼吸贡献率随季节的变化呈逐渐增加趋势。[结论] 异养呼吸对土壤总呼吸的贡献率大于自养呼吸,微生物参与下的异养呼吸成为土壤呼吸中最主要的组成部分。     

1960—2020年内蒙古自治区沙尘天气的时空演变特征及驱动因素

[目的]分析1960—2020年内蒙古自治区沙尘天气的时空演变特征及其驱动因素,科学认识气候变化背景下区域沙尘天气变化规律,为生态治理提供理论依据。[方法]利用内蒙古自治区119个气象站点1960—2020年逐日浮尘、扬沙、沙尘暴资料,采用趋势分析、M—K检验、相关分析等方法,对内蒙古自治区沙尘天气的时空演变特征及驱动因素进行分析。[结果](1)1960—2020年内蒙古自治区的各等级沙尘日数及沙尘强度指数均呈极显著的下降趋势(p<0.01),浮尘日数和扬沙日数均在1990年前后发生由多到少的突变,沙尘暴日数和沙尘强度指数无明显突变点;(2)沙尘天气的空间变化趋势表现为,西部地区发生频率高且强度较大,高值中心出现在阿拉善盟的中部及西部与乌海市交界地区,向东迅速减弱,地区间差异明显;1960—2020年,沙尘天气减弱程度西部地区较东部地区更为明显;(3)1960—2020年,内蒙古自治区沙尘天气减弱,既与增温背景下的大风日数减少(10.1 d/10 a,p<0.01)及冬春季节降水增多(2.65 mm/10 a,p<0.01)有关,也与持续多年的大规模生态治理下,NDV...     

菊芋根系分泌物改良滨海盐土的微生物机制

[目的] 探究菊芋在滨海盐土改良过程中的作用机制,分析菊芋和碱蓬根系分泌物的组分差异,明确土壤微生态环境的变化规律,进一步为盐土改良提供理论依据。[方法] 以种植菊芋和自然碱蓬植被为样地,对菊芋和碱蓬的根系分泌物进行对比分析,研究在根系分泌物作用下土壤微生物数量,微生物量碳氮,微生物群落结构以及土壤酶活性的变化,从而系统地阐明根系分泌物介导下盐土改良的微生物机制。[结果] 菊芋根际土壤中含有果糖（2.343×10^-3 g/kg）、葡萄糖（4.235×10^-3 g/kg）、蔗糖（2.670×10^-3 g/kg）,分别是碱蓬根际土壤的9.28,1.52和2.43倍。而菊芋根际与非根际中的果糖含量存在显著性差异（p<0.05）,其根际中含量为非根际的12.02倍。菊芋土壤还含有低聚果糖（蔗果三糖、蔗果四糖和蔗果五糖）,而碱蓬土壤中未检测出低聚果糖。除糖类外,菊芋根系分泌物还含有烷烃、酚、醛、酯、有机酸、醇、酮、酰胺,其组分较碱蓬土壤更为复杂且某些组分为菊芋特有〔1-氯—十八烷、正十六烷酸、2-甲基-Z-4-十四碳烯、十二酮、（Z）-9-十八碳酰胺、苯丙酸十六烷基酯等〕。功能性根系分泌物（如低聚果糖、果糖、十六烷、十八烷酸等）为根际微生物提供碳源、氮源和营养元素的同时,使菊芋根际土壤中微生物数量显著增加（p<0.05）,土壤微生物量碳、氮显著高于碱蓬土壤（p<0.05）,其值分别是碱蓬土壤的1.95和1.6倍,且菊芋根际的微生物量碳、氮约为非根际的1.69和1.50倍,优势菌群（变形菌门、放线菌门、绿弯菌门、酸杆菌门）所占比重达到90%,土壤有益菌群（Actinobacteria和Acidobacteria）的相对丰度显著增加（p<0.05）,土壤生物活性提升。此外,菊芋根际特有的分泌物（十六烷、烯醛等）,抑制了病原菌的生长,优化了微生物群落结构。除过氧化氢酶外,土壤脲酶、蔗糖酶和碱性磷酸活性显著提高（p<0.05）,其活性分别是碱蓬土壤的1.83,1.88和3.30倍。[结论] 种植菊芋后,通过根际分泌物介导,改善土壤微生物群落结构与功能,增加土壤酶活性,使土壤生物活力得以整体提升,与原生植被碱蓬相比,降低了土壤含盐量,起到了改良盐土的作用。     

太子河流域参考作物腾发量演变特征及气候影响因素分析

采用太子河流域内8个气象站1960～2005年间气象资料，应用Penman-Montieth公式计算了46年间逐月参考作物腾发量(ET₀)，对参考作物腾发量及气象要素的年际变化特征、月际变化特征及趋势进行了分析，应用统计检验方法分析了影响流域参考作物腾发量变化的主要气象因素。结果表明：近46年间太子河流域ET₀值呈现缓慢下降趋势，年内ET₀值分布以5、6月份最高，1月份最低。影响ET₀的主要气候要素按影响程度强弱依次为日照、风速、温度、相对湿度。     

阿勒泰林区放牧前后草地生态系统健康评价

[目的] 对阿勒泰林区放牧前后的草地生态系统进行健康评价,为该区退化草地恢复与管理提供科学依据。[方法] 运用了VOR综合指数生态系统健康评价模型,并结合物种多样性测度中的Margalef丰富度指数、Simpson优势度指数、Shannon-Wiener多样性指数和Alatalo均匀度指数,对阿勒泰林区草地生态系统整体状况进行了评估。[结果] ①各监测点Margalef指数差异表现在旅游区放牧前后差异极显著（p<0.01）,牧道放牧前后差异显著（p<0.05）;前山山坡、牧道的Simpson指数和Shannon-Wiener指数的放牧前后均表现出差异极显著（p<0.01）;各监测点Alatalo指数放牧前后差异不显著。②阿勒泰林区放牧后草地生态系统结构较稳定;阿勒泰林区放牧前后草地生态系统健康的组织力（O）、恢复力（R）值差异显著（p<0.05）。③VOR指数表现为牧道放牧前后差异极显著（p<0.01）,其他监测点的VOR指数放牧前后差异不显著。④各监测点放牧前后草地健康状况评价结果一致,为“健康”状态,但各监测点的VOR综合指数值存在差异。[结论] 阿勒泰林区放牧后草地生态系统结构较稳定,监测点旅游区的Margalef丰富度放牧前后差异极显著（p<0.01）,前山山坡、牧道的Simpson优势度和Shannon-Wiener多样性放牧前后均差异极显著（p<0.01）;各监测点放牧前后草地健康状况评价为“健康”。     

减施化肥和配施有机肥对酿酒葡萄梅鹿辄产量和品质的影响

[目的] 针对河西灌区土壤肥力贫瘠,酿酒葡萄产量与品质低下及无机氮肥过量施用造成的环境问题,通过探究有机氮替代部分无机氮肥对酿酒葡萄生长、产量及品质的影响,以确定酿酒葡萄适宜的有机无机氮肥配施用量。[方法] 于2018年在甘肃省张掖市临泽县进行田间试验,采用随机区组设计,设6个处理：单施化肥（C）,单施有机肥（O）,70%化肥+有机肥（0.7 CO）,50%化肥+有机肥（0.5 CO）,30%化肥+有机肥（0.3 CO）,不施肥（CK）,探究不同有机无机肥配施对酿酒葡萄梅鹿辄（Merlot）生长、产量及品质的影响。[结果] 有机肥替代部分化肥可使酿酒葡萄的产量与品质不同程度的改善,其中0.5 CO效果最优;在相同的有机肥施用量下,化肥减施50%有助于平衡酿酒葡萄营养生长与生殖生长;与CK与C处理相比,0.5 CO处理下,葡萄产量分别提高了120.76%和32.59%（p<0.05）,果实可溶性固形物分别提高了46.72%和25.21%（p<0.05）,还原糖含量分别提高了39.36%和37.46%（p<0.05）,单宁含量分别提高了23.05%和39.06%（p<0.05）,总酚含量分别提高了72.07%和54.77%（p<0.05）,花色苷含量分别提高了44.42%和48.48%（p<0.05）,糖酸比分别提高了50.42%和40.78%（p<0.05）,总酸含量降低了33.96%和16.98%（p<0.05）。[结论] 化肥减半配施有机肥（0.5 CO）既有效抑制酿酒葡萄的营养生长,又提高了葡萄产量和果实品质,在试验区的推荐施肥量为9 000 kg/hm²有机肥配施化肥（N 150 kg/hm²,P₂O₅ 135 kg/hm²及K₂O 180 kg/hm²）。     

长沙地区樟树林土壤水稳定同位素的变化及影响因素

为揭示季风区土壤水稳定同位素的变化规律，基于长沙地区樟树林0~130 cm土壤水、降水和地下水稳定同位素以及环境因子连续2年的监测数据，分析了土壤水稳定同位素的变化特征。结果表明：0~60 cm土壤水稳定同位素的季节变化明显，与降水稳定同位素存在不同程度的时滞，60 cm以下土壤水和地下水稳定同位素的季节变化均不明显。不同深度土壤水中氢稳定同位素比率（δ²H）与区域大气水线（Local meteoric water line, LMWL）的差值（Line-conditioned excess, lc）均与δ²H呈显著正相关，即土壤水中δ²H越大时，δ²H偏离 LMWL的程度越小，土壤水经历的蒸发作用越弱；土壤水中δ²H越小时，δ²H偏离LMWL的程度越大，土壤水经历的蒸发作用越强。相关分析表明，前期大气的累积蒸发（∑E）和累积温度（∑TA）对0~60 cm土壤水中 lc的影响显著。研究显示，各土壤层中相对较低的水稳定同位素比率多散布于∑E和∑TA较大的暖季，由于期间经历的蒸发富集作用更强，土壤水中lc更小，土壤水稳定同位素散点更偏离LMWL；反之亦然，从而表现出不同深度土壤水线（Soil water line, SWL）的斜率较LMWL的斜率明显偏高。综上，大气降水稳定同位素是影响土壤水稳定同位素变化的直接因素；土壤水中稳定同位素的丰度与前期大气的湿热程度有关；SWL斜率较LMWL斜率偏高的原因与降水稳定同位素及土壤水稳定同位素蒸发富集作用强度的反向季节性变化有关。     

紫外辐射对9个昆虫病原线虫品系存活率和致病力的影响

为探明紫外辐射对昆虫病原线虫（entomopathogenic nematodes,EPN）的作用,以甘肃省分离得到的昆虫病原线虫为研究材料,用室内模拟生测法,测定了经20 W、40 W紫外线辐射后,斯氏属（Steinernema feltiae,S.kraussei）和异小杆属（Heterorhabditis brevicaudis,H.megidis）4种昆虫病原线虫9个品系的存活率,并以大蜡螟（Galleria mellonella）为供试昆虫,采用改良的ONE ON ONE法,测定了其对大蜡螟的致病力。结果表明：经UV-B辐射后供试的9个昆虫病原线虫品系存活率未发生显著变化（P>0.05）。20 W紫外辐射30 min后,S.feltiae 0639C和0663TD 2品系对大蜡螟的致病力提高,其中S.felitiae 0639C致病力显著升高（P<0.05）,侵染32 h后,寄主昆虫死亡率由13.3%升高到73.3%;S.felitiae 0661YM品系的致病力显著降低（P<0.05）,侵染32 h后,寄主昆虫死亡率率由66.7%降低到0;其余各品系致病力均无显著变化。不同辐射时长和辐射强度对S.felitiae 0639C和0663TD引起寄主昆虫死亡的时间有影响,较对照组而言,经辐射预处理后,2品系线虫引起寄主昆虫死亡的时间均提前,其中S.felitiae 0639C随着辐射强度的增大引起寄主昆虫开始死亡时间提前,而S.felitiae 0663TD随着辐射强度增加引起寄主昆虫开始死亡时间延后。不同紫外辐射时长对S.felitiae 0663TD和S.felitiae 0639C致病力无显著影响,30 min、60 min、90 min、120 min辐射处理之间差异不显著（P>0.05）。研究表明,9个供试昆虫病原线虫品系均对UV-B辐射具有一定的耐受能力;20 W UV-B辐射30 min,能刺激S.felitiae 0663TD和S.felitiae 0639C侵染和致死寄主昆虫;一定的辐射时长内（120 min）,辐射时长对S.felitiae 0663TD和S.felitiae 0639C的致病力无影响。     

Dust deposition and particle size in Mali, West Africa

Dust deposition samples were collected during April and May (1990) at four sites on the inland delta region of Mali in West Africa. High dust deposition rates were measured and characterised by considerable variations between sites. A major dust plume passed over the area, following a dust storm near Gao, 500 km to the east, however the contribution of this plume to overall deposition was surprisingly small.Dust particle-size characteristics indicate mixing of dusts from three sources. Long-distance dust deposition producing fine deposits (mainly < 5 μm); dust from regional sources producing deposits mainly in the size range 20–40 μm; and local dust arising from human activities, particularly vehicle and livestock movements, producing relatively coarse material in the size range 50–70 μm, plus some fines. Local dusts appear to have made the greatest contribution to deposition, with a moderate (though less than expected) contribution from the plume and a minor contribution from long-distance dusts.These results have implications for dust deposition studies aimed at quantifying dust contributions to soils. Although these Mali dust deposition rates are high (2.5–28.6 t⁻¹ km⁻² day⁻¹), the significant proportion of locally derived dust means that new dust inputs to the soils of the Inland Delta region of Mali are small.     

Retention of Cd, Cu, Pb and Zn by Wood Ash, Lime and Fume Dust

Heavy metals are of interest due to their deleterious impacts on both human and ecosystem health. This study investigated the effectiveness of wood ash in immobilizing the heavy metals Pb, Cd, Cu and Zn from aqueous solutions. The effects of initial metal concentrations, solution pH, ash dose and reaction time on metal sorption, as well as the metal sorption mechanisms were studied. To investigate the effect of initial metal concentrations, solutions containing Cd, Zn (25, 50, 75, 100 or 125 mg L^?1), Cu (25, 50, 75, 100, 125, 150 or 175 mg L^?1) or Pb (250, 500, 750, 1000, 1250, or 1500 mg L^?1) were reacted with 10 g L^?1 ash for two hours. For the effect of pH, solutions containing 100 mg L^?1 of Cd, Cu or Zn or 1500 mg L^?1 of Pb were reacted with 15 g L^?1 ash over a pH range of 4 to 7. The wood ash was effective in immobilizing the four metals with a sorption range of 41–100 %. The amounts of metals retained by the ash followed the order of Pb > Cu > Cd > Zn. As expected, absolute metal retention increased with increasing initial metal concentrations, solution pH and ash dose. Metal retention by the ash exhibited a two-phase step: an initial rapid uptake of the metal followed by a period of relatively slow removal of metal from solution. Metal retention by the ash could be described by the Langmuir and Freundlich isotherms, with the latter providing a better fit for the data. Dissolution of calcite /gypsum minerals and precipitation of metal carbonate/sulfate like minerals were probably responsible for metal immobilization by the ash in addition to adsorption.     

Study of Worker's Exposure to Thorium,Uranium and Niobium Mineral Dust

The aim of this study is to evaluate worker’s exposure to particles, with special attention to thorium, uranium and niobiumbearing particles. A cascade impactor (CI) with six stages was used to collect particles with aerodynamic diameter in the rangeof 0.64 to 19.4 μm. The elemental mass concentrations impacted in each stage of the CI were determined using the PIXE(Particle Induced X-ray Emission) technique. The Mass Median Aerodynamic Diameter (MMAD) and elemental mass concentration in the fine fraction of aerosol (0.5 to 2.5 μm) were determined.Personal air samplers were used by workers to collect fine particles of aerosol. The concentrations of ²³²Th and ²²⁸Th in these air samplers were measured by the alpha spectrometry technique. Faeces and urine samples from the workersand their wives were analyzed to determine the thorium, uranium and niobium mass concentration (mass spectrometry) and ²³²Th, ²²⁸Th, ²³⁸U and ²³⁴U concentrations (α spectrometry) and then compared to inhabitants of regions with low metal concentrations. The analysis of thefaecesand urine samples from workers and their wives indicated that themain pathway of thorium, uranium and niobium incorporation was byingestion. The observed concentrations of niobium and uranium inurine samples from workers showed a systemic incorporation of niobium and uranium.     

Dust transportation and deposition in a superhumid environment,West Coast,South Island,New Zealand

Contemporary rates of dust deposition monitored along a 300-km section of the superhumid West Coast of New Zealand's South Island are presented. In this setting, dust is entrained primarily from the dry channels of braided glaciofluvial rivers that drain the western slopes of the Southern Alps. Measured dust deposition ranged between 0.21 and 118.9 kg⁻¹ ha⁻¹ month⁻¹, which is similar to dust deposition rates monitored in arid and semiarid environments. However, these are not considered to be sufficient for present day loess genesis. Dust deposition was highest in summer because of the greater frequency of favourable dust transporting winds, and the effect of rainfall was secondary. Dust transportation occurred mainly during the passage of nonprecipitating cold fronts or postfrontal southwesterlies. Transportation also occurred during prefrontal conditions, and in winter föhn southeasterlies were the predominant dust transporting winds to affect the West Coast.     

Effects of Electric-Arc Furnace Dust Application on Soil Properties,Sorghum Growth,and Heavy-Metal Accumulation

This study investigated the possibility of using electric-arc furnace dust (EAFD) as an acidic soil amendment. The experiments were conducted using incubation and pot experiments. In the incubation experiment, various rates of EAFD were added to an acidic soil and properties such as pH; electrical conductivity of the saturation extract (EC_se); and available phosphorus (P), potassium (K), iron (Fe), zinc (Zn), copper (Cu), manganese (Mn), lead (Pb), and cadmium (Cd) were determined. In the pot experiment rates of EAFD incorporated with soil were 0.25%, 0.5%, 1%, and 2%. The results showed that with increasing the rate of EAFD application, soil pH, EC, and available P and K were enhanced. However, addition of EAFD more than 2% caused high salinity and alkalinity; hence, it is not recommended for reclamation of this acidic soil. A pot experiment was carried out to determine its effects on sorghum (Sorghum bicolor L.) dry matter and heavy-metal accumulation. Plant dry matter was enhanced with increase the EAFD rates. The concentrations of Fe, Zn, Cu, Cd, and Pb were enhanced with the increasing rate of applied EAFD in root and shoot. However, content of these elements in plant shoot were in the normal range.     

Dust in pig buildings

It is well documented in the international scientific literature that airborne dust in pig houses can cause serious health problems for humans as well as for animals. Extensive research has been carried out in different countries during the last few decades to improve the scientific understanding of air quality issues related to intensive animal production. Research and review papers were presented at the international symposium on Dust Control in Animal Production Facilities, held in Denmark in 1999. Different techniques have been used in order to reduce dust burdens in pig confinement buildings, but up to date only the procedure of spraying oil or a mixture of oil and water has contributed to reducing the indoor dust concentrations significantly. This article summarizes the current level of understanding of dust issues in intensive animal production buildings, mainly on the basis of papers presented at the above-mentioned symposium.     

我国沙尘暴的危害及防御系统

从20世纪60年代以来,特别是90年代后期以来,沙尘暴频数急剧增加,呈现出时间早、影响广、危害大的特征.本文分析了沙尘暴天气的发生、发展及影响,叙述了近年来我国北方地区发生的沙尘暴典型事例,介绍了中国气象局2001年开始建设的沙尘暴监测预警工程.通过“中国沙尘暴预测预警服务系统”的运行与监测预报,将大大地减少和降低天气、气候极端事件的危害,达到沙尘暴天气的有效防御目的.     

Dust levels and control methods in poultry houses

This article summarizes information from the papers and posters presented at the international symposium on "Dust Control in Animal Production Facilities", held in Aarhus (Denmark) on 30 May-2 June 1999. Dust concentrations in poultry houses vary from 0.02 to 81.33 mg/m3 for inhalable dust and from 0.01 to 6.5 mg/m3 for respirable dust. Houses with caged laying hens showed the lowest dust concentrations, i.e., less than 2 mg/m3, while the dust concentrations in the other housing systems, e.g., perchery and aviary systems, were often four to five times higher. Other factors affecting the dust concentrations are animal category, animal activity, bedding materials and season. The most important sources of dust seem to be the animals and their excrements. Further studies on the effects of housing systems on dust sources and their compounds are desired for development of a healthier working environment in poultry production facilities. Adjustment of the relative humidity (RH) of the air in a broiler house to 75% will have an effect on inhalable dust, but not on respirable dust. A slight immediate effect on the respirable dust was observed after fogging with pure water or water with rapeseed oil. In an aviary system, a 50 to 65% reduction of the inhalable dust concentration was found after spraying water with 10% of oil and pure water, respectively. To obtain a higher dust reducing efficiency, improvement of techniques for application of droplets onto dust sources will be desired.     

保护性耕作与沙尘暴防治

论述了沙尘暴的发生机理和旱地保护性耕作的防尘效应。     

Dust and Bioaerosols At a Biosolids Composting Facility

Workers at composting facilities are exposed to organic dusts and bioaerosols. The bioaerosols of major concern are Aspergillus fumigatus (A. fumigatus) and endotoxin. An evaluation of employee exposure to dust, endotoxin, and A. fumigatus spores was conducted in a totally enclosed biosolids composting facility that composts biosolids with sawdust. Total and respirable dust, endotoxin, and A. fumigatus were measured during several of the major composting activities. Periodic total dust levels exceeded the OSHA PEL standard for nonspecific dust. Endotoxin levels as high as 640 ng/m³ were recorded when piles were torn down. During mixing of biosolids and sawdust, A. fumigatus counts exceeded 6,000 CFU/m³. Based on the data obtained, several mitigation measures were implemented. Evaluation of the facility after the changes were made found that levels of total dust, endotoxin, and A. fumigatus were reduced by 90 percent.