Particle Size Distribution Of Particulate Matter Research Articles

Characterization of particle exposure during tunnel excavation by tunnel boring machines.

Tunnel boring machines (TBMs) are used to excavate tunnels in a manner where the rock is constantly penetrated with rotating cutter heads. Fine particles of the rock minerals are thereby generated. Workers on and in the vicinity of the TBM are exposed to particulate matter (PM) consisting of bedrock minerals including α-quartz. Exposure to respirable α-quartz remains a concern because of the respiratory diseases associated with this exposure. The particle size distribution of PM and α-quartz is of special importance because of its influence on adverse health effects, monitoring and control strategies as well as accurate quantification of α-quartz concentrations. The major aim of our study was therefore to investigate the particle size distribution of airborne PM and α-quartz generated during tunnel excavation using TBMs in an area dominated by gneiss, a metamorphic type of rock. Sioutas cascade impactors were used to collect personal samples on 3 separate days. The impactor fractionates the dust in 5 size fractions, from 10 µm down to below 0.25 µm. The filters were weighted, and the α-quartz concentrations were quantified using X-ray diffraction (XRD) analysis and the NIOSH 7500 method on the 5 size fractions. Other minerals were determined using Rietveld refinement XRD analysis. The size and elemental composition of individual particles were investigated by scanning electron microscopy. The majority of PM mass was collected on the first 3 stages (aerodynamic diameter = 10 to 0.5 µm) of the Sioutas cascade impactor. No observable differences were found for the size distribution of the collected PM and α-quartz for the 3 sampling days nor the various work tasks. However, the α-quartz proportion varied for the 3 sampling days demonstrating a dependence on geology. The collected α-quartz consisted of more particles with sizes below 1 µm than the calibration material, which most likely affected the accuracy of the measured respirable α-quartz concentrations. This potential systematic error is important to keep in mind when analyzing α-quartz from occupational samples. Knowledge of the particle size distribution is also important for control measures, which should target particle sizes that efficiently capture the respirable α-quartz concentration.

Effect of Reaction Temperature on the Degradation and Oxidation Behavior of Particulate Matter by Nonthermal Plasma

Diesel particulate matter (PM), especially small particle size PM, has been highlighted as a hazard to the environment and people. Nonthermal plasma (NTP) has shown significant low temperature (<200°C) advantage for PM degradation. In this paper, we conducted online PM degradation experiments at different reaction temperatures with a self-built NTP injection system to investigate the changes of PM particle size distribution, micro-nano structure, graphitization degree and oxidation characteristics of elemental carbon (EC) before and after NTP action. The maximum removal rate increased from 90 ℃ (25% load) to 130 ℃ (100% load) with the increase of the load, and there was a “trade-off” effect between PM decomposition and NTP pyrolysis. The average microcrystalline length, microcrystalline spacing and microcrystalline curvature of PM particles showed an overall trend of decreasing and then increasing with the increase of temperature. When the reaction temperature was 130 ℃ (75% load), the microcrystalline structure parameters of the carbon particles showed extreme values, and the newly exposed “shells” were rearranged under the action of van der Waals force, and the graphitization of PM increased and the overall oxidation activity was weakened. The reaction between NTP and carbon particles goes through the process of surface oxidation, simultaneous oxidation of surface and interior, and the fragmentation of carbon particles to complete disappearance.

Is hydrophobic coating on glass equally efficient in reducing % soiling loss of solar PVs in clean and polluted environments?

Hydrophobic-coated glass (CS) on PV surfaces is known to reduce particulate matter (PM) accumulation. However, there is no comparative study on the % reduction in soiling loss (% RSL) on CS with respect to uncoated glass (UCS) for clean and polluted environments (higher atmospheric PM). The present field study (∼210 km2 in Gujarat, Western India) focuses on the evaluation of particle-size distribution of PM on CS and UCS, quantification of size-resolved soiling due to PM accumulation on CS and UCS, and comparison of % RSL of CS in cleaner and polluted environments. The findings show that 3 to 10 µm particles contribute to ∼21 % and ∼12 % of the total mass accumulated on CS and UCS, respectively. The observations are also validated using the theoretical adhesion model and critical rebounding velocity. Moreover, this particle-size fraction contributes to ∼50 % of the total soiling loss for CS against only ∼27 % soiling loss for UCS. Therefore, CS surfaces under polluted environments are expected to have a higher % of finer particle-size fraction in accumulated PM, which contributes significantly to the total soiling loss of CS and reduces the difference in % soiling loss between CS and UCS. Although CS reduces PM accumulation in both clean and polluted regions, the % RSL using CS is comparatively less in a polluted environment. The observations from the present study provide greater insight into the soiling aspect of solar PVs and have significant economic implications in deploying PV surfaces with hydrophobic coated glass.

Trace element characterization and source identification of particulate matter of different sizes in Hanoi, Vietnam

Particulate matter (PM) with aerodynamic diameters of <1 μm (PM1), 2.5 μm (PM2.5), and 10 μm (PM10) were investigated and analyzed for 15 trace elements in the center of Hanoi, Vietnam during April–September 2018. The mean concentrations were 40 ± 11, 53 ± 17, and 132 ± 39 μg/m3 for PM1, PM2.5, and PM10, respectively, indicating that PM pollution was severe in Hanoi. During the sampling period, the PM concentrations were little affected by local meteorological conditions. The severe PM pollution in Hanoi was significantly influenced by long-range atmospheric transport from northern and northeastern regions, with higher potential source areas for PM1. The total mean concentrations of 15 elements were 1417 ± 141, 1624 ± 159, and 2652 ± 251 ng/m3 in PM1, PM2.5, and PM10, respectively, with Al, Zn, K, Cr, and Ni as the most abundant elements. The particle-size distribution of PM and elements showed a distinct peak in PM1. The metallurgy industry, coal combustion, traffic emission, biomass burning, and soil dust were identified as major contributors of elements in three-size PM. This study implies that PM1 pollution should gain more attention regarding its level and chemical composition.

Measurement and control of containing-fluorine particulate matter emission during spent pot lining combustion detoxification process

The particle size distribution (PSD), composition, morphology, and formation mechanism of particulate matter (PM) released from the combustion of spent pot lining with and without CaSiO3 were investigated. The results showed that NaF and Na3AlF6 were found to be the main compositions of PM, and the particle size distribution of PM shows a bimodal distribution. CaSiO3 substantially inhibited the emission of PM by transforming NaF, Na3AlF6, and CaF2 into stable Ca4Si2O7F2. Moreover, CaSiO3 also limited the formation of high hazardous PM0.2 by providing SiO2, Al2O3, and NaAlSiO4 with high melting points as the core of promoting the growth of PM in particle size.

Investigation of reducing trace elements and PM emission from coal combustion by blending coal

The fine particles and their associated trace elements derived from coal combustion had a severe adverse effect on the environment or human health. In this paper, HLH (lignite) and HS (bituminous) were blended under the predetermined ratio, and the blended coal was burned in a drop tube furnace (DTF). The particle size distribution (PSD) of particulate matter (PM) and trace elements (As, Se, Pb and Cd) were investigated during the blending coal combustion. The experimental results demonstrated that the mass concentration of PM from HLH coal combustion was higher than that of HS coal, which was attributed to the thermal instability of the minerals in HLH (lignite). In addition, it was found that PSD of PM was not consistent with that of trace elements. The blending coal combustion not only suppresses PM formation, but also reduces As, Se, Pb and Cd emission due to lowering ash fusion temperature of blending coal and liquidus capture of fine particles. Compared with the calculated values, the mass concentration of PM0.2–0.5, PM0.5–1.0, PM1.0–2.5 and PM2.5–10 from HS1HLH1 (the mass ratio of HS/HLH was 1.0) combustion was reduced by 6.06 %, 45.02 %, 50.17 % and 55.59 %, respectively. At the same time, the reduction efficiency of As, Se, Pb, and Cd emission concentration in PM0.2–0.5 by HS1HLH3 were the highest (about 91.7 %, 71.06 %, 83.45 % and 73.50 %), and their emission concentration was 0.16, 0.95, 0.97 and 0.02 μg/m3. While HS1HLH1 was the most effective for reducing As, Se, Pb, and Cd emission in PM0.5–10. Lastly, above 50 % As, Pb and Cd in PM10 was existed as the mobile phase during raw coal combustion, which had a harmfulness for the environment or human being. HS1HLH1 could stabilize Se, Pb, and Cd, and their residual fraction in PM10 were 59.4 %, 49.1 % and 29.2 %, respectively.

Synthesis and Characterization Nanosilica from Rice Husk Ash Using Sol-Gel Method with Addition Of PEG-6000 and PVA

&lt;p&gt;Nano-silica (NS) from rice husk ash was successfully synthesized using a sol-gel process with the addition of &lt;em&gt;po&lt;/em&gt;&lt;em&gt;lyethylene&lt;/em&gt; glycol (PEG) 6000 and polyvinyl alcohol (PVA) as a template. The purpose of this study is to investigate the properties of NS functional groups and the effect of PEG6000 and PVA concentrations (5%, 10%, and 15% (b / v)) on the size, morphology, and distribution of nanosilica. The functional groups of NS are characterized by Fourier transform infrared (FTIR), the size and morphology of NS are characterized by scanning electron microscopy (SEM). In contrast the size analyzer characterizes the particle size distributionof particulate matter (PSA). The results indicated that the addition of PEG-6000 and PVA affected the size and morphology of NS. The FTIR spectra showed the presence of silanol (Si-OH) and siloxane (Si-O-Si) groups. According to the SEM results, the morphology of NS -PEG is round and relatively more uniform than the amorphous morphology of NS-Control and NS-PVA. Instead of PEG-6000, Sol-gel PVA can be obtained with a narrow particle size distribution.&lt;/p&gt;

Characteristics of Particulate Matter Emissions from Swine and Poultry Production Houses in the United States

HighlightsParticulate matter (PM) data were analyzed to identify PM emission characteristics among different animal types.The PM concentrations were higher in broiler chicken and swine farrowing houses and were higher in winter.The PM emissions were also higher in broiler chicken houses and swine farrowing rooms.The PM in the layer chicken house in Indiana had narrower distributions with a greater percentage of smaller particles.Abstract. Understanding the characteristics of particulate matter (PM) emissions from animal feeding operations (AFOs) is essential to address the associated health and environmental impacts and to develop control strategies to mitigate such impacts. This article reports a study of PM concentrations and emission characteristics from 26 poultry and swine production houses to investigate the similarities and differences in PM emission characteristics, e.g., concentrations, emission rates, and particle size distribution (PSD), among different animal and housing types. Concentration and emission data for PM2.5, PM10, and total suspended particulates (TSP) collected by the National Air Emission Monitoring Study (NAEMS) were used to compare the differences among different production practices and animal types. The PSDs of the PM were examined based on the PM2.5/PM10 and PM10/TSP emission rate ratios. It was discovered that the concentrations of PM varied among animal types. For poultry, the concentrations of PM were higher in broiler houses than in other poultry houses. For swine, the average concentrations of PM were higher in farrowing rooms than in swine barns. Moreover, the PM concentrations in poultry and swine houses exhibited significant seasonal trends, with higher concentrations in winter and lower concentrations in summer, which were in a reverse relationship with ventilation rates. The PM emissions also varied among animal types. For poultry, the PM emissions were significantly higher for poultry production houses in California. For swine, the PM emissions were significantly higher for farrowing rooms than other swine houses. The PSD of PM varied among animal types, with mass median diameters (MMD) in the ranges of 6.51 to 13.62 µm for poultry houses and 7.94 to 17.19 µm for swine houses. The geometric standard deviations (GSD) were in the ranges of 1.66 to 2.71 and 1.65 to 2.9 for poultry and swine PM, respectively. The PM in the layer house in Indiana had a narrower distribution (smaller GSD) with a greater percentage of smaller particles than the other poultry houses, while the PM in the broiler house in California had a broader distribution (larger GSD) than the other poultry houses. For swine, the PM in the sow barn in North Carolina had a narrower distribution (smaller GSD) than the other swine houses, while the PM in the farrowing houses in Oklahoma had a broader distribution (larger GSD) than the other swine houses. The knowledge gained from this research may provide insights for addressing the PM emissions from various animal production systems. Keywords: Concentration and emission, Particulate matter, PM2.5, PM10, Poultry, swine, PSD, TSP.

Simulative prediction of ultrafine particulate matter formation by means of different pyrolysis models

In this study, the sensitivity of two different pyrolysis models on the simulative prediction of inorganic ultrafine Particulate Matter (PM) formation is investigated. For consideration of PM formation, the volume-conserved discrete-sectional Population Balance Model (PBM) is used. The volatile release is an input parameter of the PBM and thus influences the calculated PM formation. As a representative of an empirical pyrolysis model, the Fu-Zhang model (FZM) is used. In comparison, the Chemical Percolation Devolatilization model (CPD) is taken as a representative for sophisticated pyrolysis network models. The latter takes influences of fuel composition, heating rate and particle temperature into account. The evaluation of the pyrolysis model impact is determined for a pulverized (dp=65–74μm) Chinese lignite (Zhundong) since this fuel has a relatively high volatile content and thus favors the formation of particulate matter. To investigate the influence of particle heating rate in the models, two different gas temperatures (1200 K and 1500 K, respectively 5.28·104 K s−1 and 7.51 × 104 K s−1 calculated with the energy balance) are considered. Furthermore, these conditions are selected because experimental data of the PM particle size distribution (PSD) from previous studies are available. The modeling of PSD is performed and validated with the existing experimental PSD data. These experimental data were achieved in investigations with a Hencken burner. The results of the two models (FZM and CPD) show recognizable differences in predicting the PSD. This study indicates that the CPD model improves significantly the prediction of ultrafine PM formation.

Characterization of particulate matter from heating and cooling several edible oils

Cooking fumes produced by oils at high temperatures release large amounts of fine particulate matter (PM). Exposure to cooking fumes increases the risk of many diseases. A chamber study investigated particle emission and decay characteristics originating from six types of edible oil (olive oil, soybean oil, rapeseed oil, peanut oil, corn oil and sunflower seed oil). The experiment determined the particle number concentration and particle size distribution of PM with diameters of 0.3 μm and less, 0.3–0.5 μm and 0.5–1.0 μm (PM0.3, PM0.3-0.5 and PM0.5-1.0, respectively) during the heating and cooling of the edible oils. The effects of heating power, indoor relative humidity and ventilation conditions on the corresponding particle emission and decay characteristics of olive oil and sunflower seed oil were discussed. Since the deposition and coagulation of the particles occur simultaneously in the experimental chamber, the deposition and coagulation rates of the cooling process were calculated. Two methods were compared to obtain an accurate coagulation rate.

An investigation of the leaf retention capacity, efficiency and mechanism for atmospheric particulate matter of five greening tree species in Beijing, China

Urban trees have the potential to reduce air pollution, but the retention capacity and efficiency of different tree species for atmospheric particulate matter (PM) accumulation and the underlying mechanism hasn't been well understood. To select tree species with high air purification abilities, the supplementing ultrasonic cleaning (UC) procedure was first introduced into the conventional leaf cleaning methods [single water cleaning (WC) or plus brush cleaning (BC)] for eluting the leaf-retained PM. Further updates to the methodology were applied to investigate the retention capacity, efficiency, and mechanism for PM of five typical greening tree species in Beijing, China. Meanwhile, the particle size distribution of PM on the leaves, the PM retention efficiencies of easily removable (ERP), difficult-to-remove (DRP) and totally removable (TRP) particles on the leaf (AEleaf), and the individual tree scales were estimated. The experimental leaf samples were collected from trees with similar sizes 4 (SDR) and 14days (LDR) after rainfall. When the leaves were cleaned by WC+BC, there was, on average, 29%–46% of the PM remaining on the leaves of different species, which could be removed almost completely if UC was supplemented. From SDR to LDR, the mass of the leaf-retained PM increased greatly, and the particle size distribution changed markedly for all species except for Sophorajaponica. Pinus tabuliformis retains particles with the largest average diameter (34.2μm), followed by Ginkgo biloba (20.5μm), Sabina chinensis (16.4μm), Salix babylonica (16.0μm), and S. japonica (13.1μm). S. japonica and S. chinensis had the highest AEleaf to retain the TRP and ERP of both PM1 and PM1−2.5, respectively. Conversely, S. babylonica and P. tabuliformis could retain both TRP and ERP of PM2.5–5 and PM5–10, and PM>10 and TSP with the highest AEleaf, respectively. In conclusion, our results could be useful in selecting greening tree species with high air purification abilities.

Effects of H2O and HCl on Particulate Matter Reduction by Kaolin under Oxy-coal Combustion

Little work has been performed on the effects of H2O and HCl to particulate matter (PM) reduction by kaolin under oxy-coal combustion. To determine the effect mechanism, a combustion experiment of pulverized coal mixed with kaolin was performed in a drop tube furnace. First, a low-pressure impactor was used as a sampling device to investigate the particle size distribution of PM when H2O and HCl were added during the first stage, and then a special sampling tube was used to collect the combustion products at 950 °C. Besides, the HSC Chemistry 6.0 thermodynamic software was also used for equilibrium calculations of sodium species in the drop tube furnace. The results indicate that H2O can enhance the absolute amount of PM0.2 captured by kaolin through promotion of the generation and diffusion of sodium hydroxide during oxy-coal combustion. However, the increase in PM0.2 generated from coal in the presence of H2O overrides the increase in the PM0.2 captured by kaolin; thus, the ratio of PM0.2 captured by ka...

Stormwater Suspended Solids Reduction in Sand-Zelbrite Filter Media

The use of the filtration process based on zeolite for stormwater treating has been recently increased. This study reports the results obtained from a laboratory experimental testing on a treatment unit consisting of a gravel drainage layer, a filtering media composed of zelbrite (a synthetic zeolite) and silica sand. The filter media is fed with typical stormwater particulate matter (PM) loadings. The treatment performance is evaluated in terms of total suspended solids (TSS) reduction. In addition, the transformation of PM particle size distribution (PSD) through the filtering media is also determined. The findings show that TSS reduction varies from 76% to 91% for different influent PM loads.

Particle size distributions in combined sewer overflows in a high-intensity urban catchment in Shanghai, China

To determine the dissolved-phase chemicals and solid-phase particulate matter (PM) in a combined sewer overflow (CSO), the event mean concentrations of typical particulate-band and dissolved-band contaminants were analyzed. Particulate-band chemical oxygen demand and total phosphorous formed the majority of particles, while only around 50% of the total nitrogen was found in the particulate-band. Particle size distributions (PSDs) for PM in 49 CSO samples collected during seven rainfall events, and 18 run-off samples collected during two rainfall events, were analyzed. Variation in PSDs in both CSO and dry weather flow samples occurred with sample storage time. Mean values of particle size in CSO samples were not significantly different from median values for particles within the size range from 0.41 to 3,080 μm, at a 95% confidence level. Values for D50 and D90 for PSDs of PM in both CSO and run-off samples were higher than for previous studies. It was caused by high flow rates during the operation of storm water lifting pumps. The first flush of particles in different size ranges was quantitatively evaluated using PSDs and total suspended solids in each sample. Given the prevalence of CSOs in China and other countries, knowledge of the PSD, and its variation with time, facilitates both the design of CSO treatment procedures and optimization of wastewater treatment plants; it also provides important input for modeling water treatment operations.

Spatial and temporal variation in particle size and particulate organic matter content in suspended particulate matter from peatland‐dominated catchments in Finland

AbstractProperties of suspended particulate matter play a vital role in transport processes, but information from boreal lowland river systems with high organic loads is limited. This study analysed data from 2 years of sampling at 30 locations in Finland (204 samples in total) using suspended particulate matter samplers to determine effective and absolute particle size and organic fractions. Mean d50 value was 22 and 49 µm for absolute and effective particle size, respectively. The organic fraction content ranged from 2.1% to 36% (mean 9.6%), highlighting the importance of particle organic matter for suspended particulate matter flux in the region. The results indicated that the suspended particulate matter particle size distribution and load in the study region is dominated by composite particles. There were considerable spatial and temporal variations in transport of organic fractions, effective particle size and degree of aggregation (range 1.5–93%). Headwaters and, in particular, late summer and spring flood conditions with flow peaks produced the largest composite particles, whereas agriculture‐dominated sites produced smaller but more tightly compacted particles. Organic plant fibres appeared to play a vital role in floc formation in peat‐covered catchments, whereas in agriculture‐dominated catchments, land use‐derived aggregates dominated the composition. This study provides empirical evidence of the importance of effective particle size measurement in understanding the dynamics of suspended particulate matters in boreal lowland river systems. Copyright © 2014 John Wiley &amp; Sons, Ltd.

Evaluation of a Mg-Based Additive for Particulate Matter (PM)2.5Reduction during Pulverized Coal Combustion†

This paper aims to evaluate the addition of a Mg-based additive to coal on the emission/reduction of particulate matter (PM) during coal combustion. Four pulverized coals with different mineralogical properties were investigated. Each of them was mixed with Mg-based additive and combusted at 1723 K in a lab-scale drop tube furnace (DTF). The results indicate that the Mg-based additive tested here has a pronounced impact on particle size distribution of PM and the morphologies of individual ash particles. For all of the coals tested here, the addition of the Mg-based additive increased the coarse ash fraction and substantially reduced the amount of ash particles smaller than 2.5 μm (PM2.5). This is because the Mg-based additive is able to reduce the ash melting point via the formation of low-melting eutectic compounds, which promote the coalescence among sub-micrometer mineral particles. The effect of the Mg-based additive on PM2.5 reduction also depends upon the properties of the original minerals present...

Effects of Cyclone Diameter on Performance of 1D3D Cyclones: Cutpoint and Slope

Cyclones are a commonly used air pollution abatement device for separating particulate matter (PM) from air streams in industrial processes. Several mathematical models have been proposed to predict the cutpoint of cyclones as cyclone diameter varies. The objective of this research was to determine the relationship between cyclone diameter, cutpoint, and slope of the fractional efficiency curve (FEC) based on empirical data. Tests were performed comparing cutpoints and FEC slopes of 15.24, 30.48, 60.96, and 91.44 cm (6, 12, 24, and 36 in.) diameter cyclones with poly-disperse PM having an aerodynamic mass median diameter near 10 µm. The mass of PM collected by the cyclones and the mass and particle size distributions of PM that penetrated the cyclones were used to determine each cyclone's FEC, characterized by a cutpoint and slope. The cutpoints of cyclones showed no relationship to cyclone diameter, while the slope of the cyclone FECs increased as cyclone diameter increased. Statistically different collection efficiencies were observed among the 30.48, 60.96, and 91.44 cm (12, 24, and 36 in.) diameter cyclones. None of the previously published mathematical models analyzed in this article accurately predicted cyclone cutpoint.

Theoretical Study of the Impact of Particulate Matter Gravitational Settling on Ambient Coarse Particulate Matter Monitoring for Agricultural Emissions

The particle size distributions (PSDs) of particulate matter (PM) in the downwind plume from simulated sources of a cotton gin were analyzed to determine the impact of PM settling on PM monitoring. The PSD of PM in a plume varies as a function of gravitational settling. Gravitational settling has a greater impact on the downwind PSD from sources with PSDs having larger mass median diameters (MMDs). The change in PSD is a function of the source PSD of emitted PM, wind speed, and downwind distance. Both MMD and geometric standard deviation (GSD) in the downwind plume decrease with an increase in down-wind distance and source MMD. The larger the source MMD, the greater the change in the downwind MMD and GSD. Also, the greater the distance from the source to the sampler, the greater the change in the downwind MMD and GSD. Variations of the PSD in the downwind plume significantly impact PM10 sampling errors associated with the U.S. Environmental Protection Agency (EPA) PM10 samplers. For the emission sources with MMD >10 µm, the PM10 oversampling rate increases with an increase in downwind distance caused by the decrease of GSD of the PSD in the downwind plume. Gravitational settling of particles does not help reduce the oversampling problems associated with the EPA PM10 sampler. Furthermore, over-sampling rates decrease with an increase of the wind speed.