Uncertainty Budget of the SMPS–APS System in the Measurement of PM1, PM2.5, and PM10

The effects of particulate matter on environment and public health have been widely studied in recent years. In spite of the presence of numerous studies about this topic there is no agreement on the relative importance of the particles' size and origin with respect to health effects among researchers. Nevertheless, air quality standards are moving, as the epidemiological attention, towards greater focus on the smaller particles. The most reliable method used in measuring particulate matter (PM) is the gravimetric method since it directly measures PM concentration, guaranteeing an effective traceability to international standards. This technique, however, neglects the possibility to correlate short term intraday atmospheric parameter variations that can influence ambient particle concentration and size distribution as well as human activity patterns. Besides, a continuous method to determine PM concentrations through the measurement of the number size distribution is the system constituted by a Scanning Mobility Particle Sizer (SMPS) and an Aerodynamic Particle Sizer (APS). In this article, the evaluation of the uncertainty budget in measuring PM through the SMPS–APS system, as well as a metrological comparison with the gravimetric reference method in order to analyze the compatibility, was carried out and applied with reference to an experimental campaign developed in a rural site. This choice allowed to assume the hypothesis of spherical particle morphology. The average PM₁₀, PM_2.5, and PM₁ uncertainties obtained for the SMPS–APS system are equal to 27%, 29%, and 31%, respectively. Here the principle influence parameter is the particle density that has to be directly measured with low uncertainty in order to reduce the PM uncertainty.     

A Shelter to Protect a Passive Sampler for Coarse Particulate Matter,PM10 − 2.5

This work designed and tested a shelter to protect a passive sampler for measuring coarse particulate matter, PM _{10 ? 2.5} . The shelter protects the sampler from precipitation and reduces the effects of wind on the deposition of particles to its collection surface. Six shelters were tested in a wind tunnel at three wind speeds: 2, 8, and 24 km hr ^?1 . Shelter performance was expressed as the ratio of PM _{10 ? 2.5} measured with the passive samplers to that measured with a filter-based dichotomous sampler. For most shelters, the PM _{10 ? 2.5} ratio averaged across wind speeds was well above one (2.4 to 8.5) and was generally dependent on wind speed. However, the PM _{10 ? 2.5} ratio for one shelter, the Flat Plates shelter, was 1.04 with substantially less effect on particle deposition from wind speed. Eight week-long field tests were conducted to compare PM _{10 ? 2.5} measured with a passive sampler installed in a Flat Plates shelter to that measured with a collocated filter-based dichotomous sampler. In these tests, the mean PM _{10 ? 2.5} ratio was 1.29. The linear relationship between PM _{10 ? 2.5} measured passively to that measured with the filter-based sampler had a Pearson correlation coefficient of 0.97 and was not significantly affected by the addition of weekly mean wind speed (p = 0.35). Although temperature was significant in this regression model (p = 0.02), it only improved the relationship marginally. The passive sampler in a Flat Plates shelter offers an inexpensive means to assess ambient PM _{10 ? 2.5} without on-site measurement of wind speed.     

A Novel Multifilter PM10–PM2.5 Sampler (MFPPS)

A novel multifilter PM₁₀–PM_2.5 sampler (MFPPS) that enables the collection of four PM₁₀ and four PM_2.5 samples simultaneously has been developed and tested. The MFPPS uses a PM₁₀ impactor as the inlet and operates at 33.4 L/min. After the inlet, the aerosol flow is divided half by a Y-type fitting. Half of the flow is directed into four PM₁₀ filter cassettes, while the other half is directed into four PM_2.5 filter cassettes after the aerosols are further classified by a PM_2.5 impactor. An active flow control system consisting of two mass flow controllers (MFCs), one for PM₁₀ and the other for PM_2.5, is used to fix the total flow rate of 16.7 L/min for four PM₁₀ or four PM_2.5 channels based on the ambient pressure and temperature. To ensure flow rate uniformity through each of the four PM₁₀ or four PM_2.5 filter cassettes, an orifice is assembled behind each of the filter cassettes to increase the pressure drop, such that the flow rates of eight sampling lines are nearly equal using just two MFCs. The MFPPS was calibrated in the laboratory for particle collection efficiency curves first. Then, the ambient PM concentrations were compared with those of other two collocated FRM samplers, the dichotomous PM₁₀ and the EPA WINS PM_2.5 sampler in the field study. Calibration results showed the cutoff aerodynamic diameters of the PM₁₀ and PM_2.5 impactors were 9.8 ± 0.1 and 2.5 ± 0.05 μm, respectively. Field comparison results indicated PM₁₀ and PM_2.5 concentrations agreed well with the other two PM samplers.     

中国大陆生物质燃烧排放的TSP,PM10,PM2.5清单

根据2000年各省市生物质的消耗资料,结合查阅的排放因子,计算了中国大陆生物质燃烧所排放的TSP,PM10,PM2.5的总量及各省市的排放清单,并进一步细化到县、区级行政区.研究表明,生物质燃烧排放的颗粒物在地区间的分布极不均衡,排放量较大的包括华东、中南地区的各省市;各种生物质燃烧对颗粒物的排放量的贡献差异很大,其中秸秆和薪材是最主要来源;单位面积生物质燃烧排放颗粒物较高的地区由东北至中南围绕中国的主要农业产地呈带状分布.     

PM10和PM2.5的危害及控制对策

PM10和PM2.5不止会降低环境质量,还会对人体产生巨大危害,直接威胁着人类健康。所以,如果不对此加以控制,人类的生存条件将迅速恶化,产生的后果是极为可怕的。为了减轻PM10和PM2.5对环境、人体的危害,相关部门必须尽快采取强有力的管理措施,遏制环境问题进一步恶化的趋势。文章从PM10和PM2.5造成的危害出发,提出了几项控制建议。     

PM2.5和PM10监测数据“倒挂”成因浅析

针对PM2.5和PM10在线监测过程中出现的"数据倒挂"现象进行成因分析,并提出对应的改进和保障措施,确保给出有效而高质量的PM 2.5监测数据。     

环境空气监测中TSP、PM10、PM2.5的监测总结

环境监测是环境保护的喉舌,是生态环境保护的前沿阵地,只有让环境监测发挥其应有的职能,提供科学有效的监测数据,才能更好地保护环境.通过对环境空气监测中TSP、PM10、PM2.5的手工监测技术的深入探讨,旨在提高环境监测人员的技术水平.     

春节期间烟花爆竹燃放对空气中PM2.5和PM10的影响

采集某城市近三年的春节假期期间空气质量数据,分析了近三年春节假期期间PM2. 5和PM10的变化情况,研究了该城市春节期间管控烟花爆竹燃放对空气中PM2. 5和PM10的影响,结果表明:烟花爆竹燃放对PM2. 5和PM10影响的规律基本一致,在大年三十和初一凌晨0点和中午12点后会出现明显峰值;随着近三年管控烟花爆竹燃放的力度加大,PM2. 5和PM10浓度下降明显,管控成效显著。     

2016～2020年上海市金山区PM2.5及PM10污染状况分析

基于2016～2020年上海市金山区大气中PM2.5及PM10监测数据,对PM2.5、PM10及其比值进行年度、月度等类型的污染特征分析.分析结果表明:金山区近五年PM2.5及PM10年均浓度呈明显的下降趋势,月度变化呈现冬春季节浓度高于夏秋季节的趋势,日变化呈双峰型;金山区PM2.5/PM10比值较大,细颗粒物比例较...     

和田市沙尘与非沙尘天PM2.5和PM10中水溶性离子特征分析

为了比较和田市沙尘天和非沙尘天中PM_(2.5)和PM_(10)水溶性离子的组分特征及其差异,利用离子色谱仪分析其变化特征。结果显示,沙尘天总水溶性离子的平均浓度总体上均高于非沙尘天,Ca~(2+)、SO_4~(2-)、Cl~-、Na~+是和田市沙尘天和非沙尘颗粒物中水溶性离子重要组成部分;NO_3~-的二次转换不明显,而SO_4~(2-)则发生了明显的二次转换;沙尘天和非沙尘天阴离子有不同程度的亏损,颗粒物整体呈现偏碱性的状态。     

PM2.5和PM10监测数据“倒挂”与环境温度、湿度的关系

采用赛默飞世尔FH62C14型和5030 SHARP型在线监测仪分别对环境空气中的PM10和PM2.5开展监测,统计监测数据同时记录环境温度和湿度信息,探讨PM2.5和PM10在线监测数据"倒挂"现象与环境温度和湿度之间的关系。结果表明,一般情况下(温度5~40℃,相对湿度30%~90%),PM2.5和PM10在线监测数据"倒挂"的概率呈现出温度升高则变小,湿度升高则变大的趋势。     

Mechanism of micro-particle motion across falling liquid cylinder for PM2.5 separation (Ⅱ)Efficiency of PM2.5 separation from heavy-duty diesel exhausts

根据（Ⅰ）报提出的液柱交叉流PM_2.5颗粒附面运动与吸收机理及模型计算方法,设计了以钻井废水吸收钻井柴油机尾气PM_2.5的液柱交叉流吸收现场试验装置。吸收器具有高温绝热蒸发与低温绝热冷凝两个操作空间,柴油机尾气通过绝热蒸发空间降温增湿,携带水蒸气到绝热冷凝空间通过扩散在液柱表面冷凝,形成热泳和扩散双重强化PM_2.5吸收分离机制。模型计算显示该机制下0.01～1.0 μm范围内颗粒粒径与分离效率关系不显著,设计工况下单液柱分离效率1.17%～1.36%。由200排三角形布置的液柱构成的吸收器总体分离效率90%～93%。该过程可同时蒸发废水461.2 kg·h^-1。但颗粒分离效率随蒸发负荷及液柱温度的上升而降低,温升10℃、单液柱分离效率降低60%。现场模型试验装置监测数据与本文模型计算总分离效率基本接近。     

An investigation into the electrodeposition of Au–Cu-matrix particulate composites

The electrodeposition of AuCu/B4C composites from alkaline baths containing free cyanide is described. The electrochemical behaviour of the bath and the metallographic and crystalline structures of the electrodeposited alloys were studied with and without addition of particles. Electrochemical instabilities were observed and their bearing on the structure of both pure matrix and composite electrodeposits is shown and elucidated. The electrochemical and structural conclusions on the AuCu/B4C system are thought to be general for alloy-matrix composite plating with nonconductive particles.     

Characterization of PM2.5-Bound Polycyclic Aromatic Hydrocarbons in the Ambient Air of Győr,Hungary

ABSTRACT

In Hungary, the nationwide monitoring of PM10-bound polycyclic aromatic hydrocarbons (PAHs) in ambient air is great importance for a number of reasons related to human health, the environment and compliance with European Union legislation. However, the measurement of PAH concentrations in PM2.5 aerosol fraction has not been carried out. Therefore, the concentration, distribution and sources of PM2.5-bound PAHs at different urban sites of Gy?r were investigated in a heating season. The total PAH concentrations (sum of 19 individual PAH compounds) ranged from 1.32 to 37.27 ng/m³ with the mean value of 10.54 ng/m³. The high molecular weight PAHs with 5 and 6 aromatic rings were the most abundant PAHs in PM2.5 aerosol samples, which averaged 82% of total PAHs. Using benzo(a)pyrene (BaP) equivalent approach on the concentration data of carcinogenic PAH species, BaP and indeno(1,2,3-cd)pyrene contributed the highest carcinogenic exposure equivalent (1.25 and 0.19 ng/m³ on average). However, the incremental lifetime cancer risk (ILCR) values for resident children and adults indicated low-potential cancer risk (ILCR < 10^?6). The source apportionment results reflected that the major sources of PAH compounds in the Gy?r atmosphere were fossil fuel combustion and vehicle emissions.     

广州冬季PM10和PM2.5中有机碳与元素碳浓度水平及分布特征

于2002年1月至2月在广州市3个点采集不同粒径(PM2.5和PM10)大气气溶胶样品,测定了PM2.5,PM10及其中的有机碳(OC)和元素碳(EC)浓度,探讨了广州市冬季碳气溶胶的污染特征.结果表明,PM2 5和PM10平均浓度分别为105.9 μg/m3及161.7 μg/m3,其中PM25中的OC,EC浓度分别为22.6μg/m3和8.3μg/m3,PM10中的OC,EC浓度分别为29.4和10.4 μg/m3.PM2.5和PM10的总碳气溶胶含量分别为40.5%和35.7%.PM2.5和PM10中OC/EC的比值平均为2.7,这与大多数城市大气的OC/EC比值接近.OC与EC的相关性很好(R＞0.9),表明OC与EC的排放源相同.估算的PM2.5中次生有机碳(SOC)平均浓度为12.1μg/m3,占PM2.5中总OC浓度的49.6%;PM10的SOC平均浓度为14.3 μg/m3,占PM10中总OC的44.8%.     

One– and Three–Hour PM2.5 Characterization,Speciation, and Source Apportionment Using Continuous and Integrated Samplers

Ammonium nitrate and semivolatile organic compounds (SVOC) are significant components of fine particles in many urban atmospheres. These components, however, are not properly measured by current EPA accepted methods, such as the R&P TEOM monitor, due to loss of semivolatile material (SVM) from particles in the heated environment of the filter during sampling. The accurate determination of semivolatile material is important due to the possible effects of these species on human health, visibility, and global climate change. The concentration and composition of fine particulate material were determined using a combination of continuous and integrated samplers at the Brigham Young University–EPA Environmental Monitoring for Public Access and Community Tracking (BYU–EPA EMPACT) monitoring site in Salt Lake City, Utah over a six–day sampling period (30 January to 4 February) during the winter of 2001. Continuous samples were collected using a RAMS (total PM_2.5 mass), a TEOM monitor (nonvolatile PM_2.5 mass), an Aethalometer (elemental carbon), a TSI CPC (particle count), and a Nephelometer (light scattering by particles, b_sp). Fine particle composition and mass were determined on a three–hour basis using the PC–BOSS diffusion denuder sampler. Total PM_2.5 mass–determined with the RAMS agreed with constructed mass determined from the chemical composition measured in collocated PC–BOSS–integrated samples. Results from this study indicate that semivolatile material (ammonium nitrate and semivolatile organic compounds) is a significant component of fine particle mass. Semivolatile organic compounds were the major contributor to light scattering during the six–day sampling period. Semivolatile nitrate, but not organic material, was suggested to be hygroscopic by the nephelometric data. The majority of the SVM observed appeared to be secondary material formed from photochemical reactions of the organic and NO_x emissions from mobile sources and wood smoke combustion.     

Experimental study on particulate emission of a diesel engine fueled with blended ethanol–dodecanol–diesel

Experiments were conducted on a 4-cylinder direct-injection diesel engine which has a compressing ratio of 19, using ultra low sulfur diesel blended with ethanol using 1–1.5% by volume of 1-dodecanol as the solvent to investigate the particulate emissions of the engine under five engine loads and at engine speeds of 1800 and 2400 rev/min. Blended fuels containing 6.1%, 12.2%, 18.2% and 24.2% by volume of ethanol, corresponding to 2%, 4%, 6% and 8% by mass of oxygen in the blended fuel, were used. At both engine speeds, with an increase in ethanol in the fuel, the smoke opacity, the particulate mass concentration and the total number of nano-size particles are all reduced. A diesel oxidation catalyst (Finnkat) was used and found to further reduce particulate emission. The smoke opacity, the particulate mass concentration and the total number concentration at 2400 rev/min are higher than those at 1800 rev/min.     

Effect of WC particle size on the microstructure and mechanical properties of Ni–Co coarse grain cemented carbide

The effect of different WC grain size additions on the microstructure and grain distribution of Ni–Co coarse crystalline cemented carbide was studied. And then the effect of grain distribution on the mechanical properties of cemented carbide was discussed. The effect of WC grain size on the grain size and coherency of cemented carbide was analyzed by microstructure. And the distribution of grains in the microstructure was investigated by the truncation method. The addition of fine (1.1–1.4 μm), medium (2.3–2.7 μm), and coarse WC (5.6–6.0 μm) particles can increase the nucleation rate of WC grains in the bonded phase. And the higher grain growth driving force can produce the theoretical limitation of nucleation and inhibit the coarsening of WC grains to a certain extent. The WC grain size has an insignificant effect on the frequency of the occurrence of super-coarse grains in coarse crystalline cemented carbide. The average grain size and super coarse grains in microstructure gradually decrease, which promotes the improvement of transverse rupture strength. The increase of the adjacent degree and the decrease of the mean free path reduce which is beneficial to the improvement of the corrosion resistance of the alloy. The best overall performance of the alloy is achieved when fine-grained WC is added.