scholarly journals Spatial and Seasonal Variations of PM Concentration and Size Distribution in Manure-Belt Poultry Layer Houses

2019 ◽  
Vol 62 (2) ◽  
pp. 415-427 ◽  
Author(s):  
Reyna M. Knight ◽  
Xinjie Tong ◽  
Zhenyu Liu ◽  
Sewoon Hong ◽  
Lingying Zhao
Keyword(s):  
Particle Size ◽  
Particulate Matter ◽  
Size Distribution ◽  
Seasonal Variations ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Potential Health ◽  
Significant Difference ◽  
Autumn And Winter ◽  
Mass Concentrations

Abstract. Poultry layer houses are a significant source of particulate matter (PM) emissions, which potentially affect worker and animal health. Particulate matter characteristics, such as concentration and size distribution inside layer houses, are critical information for assessment of the potential health risks and development of effective PM mitigation technologies. However, this information and its spatial and seasonal variations are lacking for typical layer facilities. In this study, two TSI DustTrak monitors (DRX 8533) and an Aerodynamic Particle Sizer (APS 3321) were used to measure PM mass concentrations and number-weighted particle size distributions in two typical manure-belt poultry layer houses in Ohio in three seasons: summer, autumn, and winter. Bimodal particle size distributions were consistently observed. The average count median diameters (mean ±SD) were 1.68 ±0.25, 2.16 ±0.31, and 1.87 ±0.07 µm in summer, autumn, and winter, respectively. The average geometric standard deviations of particle size were 2.16 ±0.23, 2.16 ±0.18, and 1.74 ±0.17 in the three seasons, respectively. The average mass concentrations were 67.4 ±54.9, 289.9 ±216.2, and 428.1 ±269.9 µg m-3 for PM2.5; 73.6 ±59.5, 314.6 ±228.9, and 480.8 ±306.5 µg m-3 for PM4; and 118.8 ±99.6, 532.5 ±353.0, and 686.2 ±417.7 µg m-3 for PM10 in the three seasons, respectively. Both statistically significant (p < 0.05) and practically significant (difference of means >20% of smaller value) seasonal variations were observed. Spatial variations were only practically significant for autumn mass concentrations, likely due to external dust infiltration from nearby agricultural activities. The OSHA-mandated permissible exposure limit for respirable PM was not exceeded in any season. Keywords: Air quality, Particulate matter, Poultry housing, Seasonal variation, Spatial variation.

scholarly journals Size-segregated particle number and mass concentrations from different emission sources in urban Beijing

2020 ◽  
Vol 20 (21) ◽  
pp. 12721-12740
Author(s):  
Jing Cai ◽  
Biwu Chu ◽  
Lei Yao ◽  
Chao Yan ◽  
Liine M. Heikkinen ◽  
...  
Keyword(s):  
Particle Size ◽  
Particulate Matter ◽  
Source Apportionment ◽  
Particle Number ◽  
Fine Particles ◽  
Size Distributions ◽  
Vehicular Emissions ◽  
Particle Size Distributions ◽  
Chemical Fingerprints ◽  
Mass Concentrations

Abstract. Although secondary particulate matter is reported to be the main contributor of PM2.5 during haze in Chinese megacities, primary particle emissions also affect particle concentrations. In order to improve estimates of the contribution of primary sources to the particle number and mass concentrations, we performed source apportionment analyses using both chemical fingerprints and particle size distributions measured at the same site in urban Beijing from April to July 2018. Both methods resolved factors related to primary emissions, including vehicular emissions and cooking emissions, which together make up 76 % and 24 % of total particle number and organic aerosol (OA) mass, respectively. Similar source types, including particles related to vehicular emissions (1.6±1.1 µg m−3; 2.4±1.8×103 cm−3 and 5.5±2.8×103 cm−3 for two traffic-related components), cooking emissions (2.6±1.9 µg m−3 and 5.5±3.3×103 cm−3) and secondary aerosols (51±41 µg m−3 and 4.2±3.0×103 cm−3), were resolved by both methods. Converted mass concentrations from particle size distributions components were comparable with those from chemical fingerprints. Size distribution source apportionment separated vehicular emissions into a component with a mode diameter of 20 nm (“traffic-ultrafine”) and a component with a mode diameter of 100 nm (“traffic-fine”). Consistent with similar day- and nighttime diesel vehicle PM2.5 emissions estimated for the Beijing area, traffic-fine particles, hydrocarbon-like OA (HOA, traffic-related factor resulting from source apportionment using chemical fingerprints) and black carbon (BC) showed similar diurnal patterns, with higher concentrations during the night and morning than during the afternoon when the boundary layer is higher. Traffic-ultrafine particles showed the highest concentrations during the rush-hour period, suggesting a prominent role of local gasoline vehicle emissions. In the absence of new particle formation, our results show that vehicular-related emissions (14 % and 30 % for ultrafine and fine particles, respectively) and cooking-activity-related emissions (32 %) dominate the particle number concentration, while secondary particulate matter (over 80 %) governs PM2.5 mass during the non-heating season in Beijing.

scholarly journals Size segregated particle number and mass emissions in urban Beijing

2020 ◽  
Author(s):  
Jing Cai ◽  
Biwu Chu ◽  
Lei Yao ◽  
Chao Yan ◽  
Liine M. Heikkinen ◽  
...  
Keyword(s):  
Particle Size ◽  
Particulate Matter ◽  
Source Apportionment ◽  
Particle Number ◽  
Related Factor ◽  
Size Distributions ◽  
Vehicular Emissions ◽  
Particle Size Distributions ◽  
Chemical Fingerprints ◽  
Mass Concentrations

Abstract. Although secondary particulate matter is reported to be the main contributor of PM2.5 during haze in Chinese megacities, primary particle emissions also affect particle concentrations. In order to improve estimates of the contribution of primary sources to the particle number and mass concentrations, we performed source apportionment analyses using both chemical fingerprints and particle size distributions measured at the same site in urban Beijing from April to July 2018. Both methods resolved factors related to primary emissions, including vehicular emissions and cooking emissions, which together make up 76 % and 24 % of total particle number and organic aerosol (OA) mass, respectively. Similar source-types, including particles related to vehicular emissions (1.6 ± 1.1 μg m−3; 2.4 ± 1.8 × 103 cm−3 and 5.5 ± 2.8 × 103 cm−3 for two traffic-related components), cooking emissions (2.6 ± 1.9 μg m−3 and 5.5 ± 3.3 × 103 cm−3) and secondary aerosols (51 ± 41 μg m−3 and 4.2 ± 3.0 × 103 cm−3) were resolved by both methods. Converted mass concentrations from particle size distributions components were comparable with those from chemical fingerprints. Size distribution source apportionment separated vehicular emissions into a component with a mode diameter of 20 nm (Traffic-ultrafine) and a component with a mode diameter of 100 nm (Traffic-fine). Consistent with similar day and night-time diesel vehicle PM2.5 emissions estimated for the Beijing area, Traffic-fine, hydrocarbon-like OA (HOA, traffic-related factor resulting from source apportionment using chemical fingerprints), and black carbon (BC) showed similar diurnal patterns, with higher concentrations during the night and morning than during the afternoon when the boundary layer is higher. Traffic-ultrafine particles showed the highest concentrations during the rush-hour period, suggesting a prominent role of local gasoline vehicle emissions. In the absence of new-particle formation, our results show that vehicular (14 % and 30 % for ultrafine and fine particles, respectively) and cooking (32 %) emissions dominate the particle number concentration while secondary particulate matter (over 80 %) governs PM2.5 mass during the non-heating season in Beijing.

Effects of CVS Tunnel, Ambient and Instrument Dilution on Characteristics of Nano Diesel Particulate Matter Evolution

2012 ◽  
Author(s):  
Yuebin Wu ◽  
Nigel N. Clark ◽  
Daniel K. Carder
Keyword(s):  
Particle Size ◽  
Particulate Matter ◽  
Diesel Engine ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Diesel Particulate Matter ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Diesel Particulate ◽  
Exhaust Plume

In 2007, U.S. certification standards for heavy duty on-road diesel engine particulate matter (PM) emissions were reduced from 0.1g/bhp-hr to 0.01g/bhp-hr, representing an order of magnitude reduction in pollutant level. The Tier 4 standards for nonroad diesel engines, being phased in from 2008 through 2015, also require similar level of reduction in PM. Most conventional diesel engines could meet these low PM standards, once equipped with a diesel particulate filter (DPF). However, accurate, repeatable measurements of this PM may pose significant challenges. Gravimetric PM measurement involves diluting exhaust, then collecting the resultant aerosol sample on approved filter media. Few data exist to characterize the evolution of particulate matter (PM) in dilution tunnels, particularly at very low PM mass levels. Data are lacking as well, for PM evolution in portable dilution instruments and in exhaust plumes downstream of the tailpipe. Size distributions of ultra-fine particles in the diesel exhaust from a naturally aspirated ISUZU C240 diesel engine, equipped with a DPF, were studied. Particle size distribution data, during steady-state engine operations, were collected using a Cambustion DMS500 Fast Particulate Spectrometer. The effects of dilution ratios, dilution rates, and residence times on the diesel particulate matter (DPM) size distributions were analyzed and discussed. Measurements were made for three dilution methods: dilution in standard primary and secondary-dilution tunnels with a full scale Constant Volume Sampler (CVS) system, instrument dilution with a Portable Particulate Measurement Device (PPMD), and ambient dilution at the post-tailpipe exhaust plume centerline. Gaseous emissions measurements were utilized as surrogate confirmation of adequate mixing at the various measurement locations, as well as an indicator of dilution ratios. Tunnel sample results indicated varying size distributions at tunnel cross sections where the flow was still developing. Evolution of particle-size distributions was observed even for fully mixed primary flow conditions. Size distributions at the end of the secondary dilution tunnel were observed to vary with different secondary-dilution ratios. Particle-size distributions of post-tailpipe and PPMD test results were analyzed and compared with those results collected from the full-flow tunnel. Results from post-tailpipe sampling indicate that nucleation was the dominant process when the exhaust plume was diluted along the post-tailpipe centerline. Results from PPMD dilution measurements indicate that change of particle-size-distribution curves, including number count and mass concentration levels, were not as strongly correlated to dilution ratios as were the results from the other two sampling methods. This study shows that particle-size distributions measured inside full-flow dilution tunnel can adequately mimic freshly emitted exhaust sampled immediately post-tailpipe.

The moment ratios of particle size distributions in some simple growth models

1980 ◽  
Vol 17 (4) ◽  
pp. 956-967 ◽  
Author(s):  
H. L. MacGillivray
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Growth Model ◽  
Hazard Rate ◽  
Growth Models ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Initial Size ◽  
The Moment ◽  
Simple Growth

Important parameters of particle size distributions in dispersed systems in engineering and related fields are ratios of moments and inverse powers of these ratios, known as mean sizes. The variation in these parameters is examined for the simplest growth model in which the size distribution is translated, and the results for this process considered in relation to the problems of models of other growth processes. For initial size distributions with monotone hazard rate, the results are particularly significant, and the properties of the normalised moments of other distributions are also considered.

scholarly journals Fast time response measurements of particle size distributions in the 3–60 nm size range with the nucleation mode aerosol size spectrometer

2018 ◽  
Vol 11 (6) ◽  
pp. 3491-3509 ◽  
Author(s):  
Christina Williamson ◽  
Agnieszka Kupc ◽  
James Wilson ◽  
David W. Gesler ◽  
J. Michael Reeves ◽  
...  
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Cloud Condensation Nuclei ◽  
Radiation Budget ◽  
Fast Time ◽  
Size Distributions ◽  
Free Troposphere ◽  
Particle Size Distributions ◽  
Nucleation Mode ◽  
Data Inversion

Abstract. Earth's radiation budget is affected by new particle formation (NPF) and the growth of these nanometre-scale particles to larger sizes where they can directly scatter light or act as cloud condensation nuclei (CCN). Large uncertainties remain in the magnitude and spatiotemporal distribution of nucleation (less than 10 nm diameter) and Aitken (10–60 nm diameter) mode particles. Acquiring size-distribution measurements of these particles over large regions of the free troposphere is most easily accomplished with research aircraft. We report on the design and performance of an airborne instrument, the nucleation mode aerosol size spectrometer (NMASS), which provides size-selected aerosol concentration measurements that can be differenced to identify aerosol properties and processes or inverted to obtain a full size distribution between 3 and 60 nm. By maintaining constant downstream pressure the instrument operates reliably over a large range of ambient pressures and during rapid changes in altitude, making it ideal for aircraft measurements from the boundary layer to the stratosphere. We describe the modifications, operating principles, extensive calibrations, and laboratory and in-flight performance of two NMASS instruments operated in parallel as a 10-channel battery of condensation particle counters (CPCs) in the NASA Atmospheric Tomography Mission (ATom) to investigate NPF and growth to cloud-active sizes in the remote free troposphere. An inversion technique to obtain size distributions from the discrete concentrations of each NMASS channel is described and evaluated. Concentrations measured by the two NMASS instruments flying in parallel are self-consistent and also consistent with measurements made with an optical particle counter. Extensive laboratory calibrations with a range of particle sizes and compositions show repeatability of the response function of the instrument to within 5–8 % and no sensitivity in sizing performance to particle composition. Particle number, surface area, and volume concentrations from the data inversion are determined to better than 20 % for typical particle size distributions. The excellent performance of the NMASS systems provides a strong analytical foundation to explore NPF around the globe in the ATom dataset.

Determination of Particle Size Distribution of Nano-TiO2 Coating Film by AFM and Image Analysis

2010 ◽  
Vol 177 ◽  
pp. 22-24
Author(s):  
Zheng Min Li ◽  
Zhi Wei Chen ◽  
Min Tan ◽  
Ke Jing Xu ◽  
Bing Jiang
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Coating Film ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Nano Tio2 ◽  
Tio2 Particles ◽  
Atom Force Microscope

Nano-TiO2 coating film is one of the efficient photocatalysts. The particle size distribution of TiO2 has important influence on photocatalytic activity. A new method to determine the particle size distribution of TiO2 nano-film coated on ceramic was developed, by which the images of film acquired by Atom force microscope (AFM) were processed, and TiO2 particles contacted with others were separated and detected. The particle size distributions of two TiO2 nano-films were determined.

scholarly journals Particle size distribution of nitrated and oxygenated polycyclic aromatic hydrocarbons (NPAHs and OPAHs) on traffic and suburban sites of a European megacity: Paris (France)

2012 ◽  
Vol 12 (18) ◽  
pp. 8877-8887 ◽  
Author(s):  
J. Ringuet ◽  
E. Leoz-Garziandia ◽  
H. Budzinski ◽  
E. Villenave ◽  
A. Albinet
Keyword(s):  
Particle Size ◽  
Polycyclic Aromatic Hydrocarbons ◽  
Size Distribution ◽  
Aromatic Hydrocarbons ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Oxygenated Polycyclic Aromatic Hydrocarbons ◽  
Polycyclic Aromatic ◽  
Traffic Site ◽  
Suburban Site

Abstract. The size distribution of particulate nitrated and oxygenated polycyclic aromatic hydrocarbons (NPAHs and OPAHs) was determined during two field campaigns at a traffic site in summer 2010 and at a suburban site during the MEGAPOLI (Megacities: Emissions, urban, regional and Global Atmospheric POLlution and climate effects, and Integrated tools for assessment and mitigation) experiment in summer 2009. Both, OPAHs and NPAHs were strongly associated (>85%) to fine particles (Dp< 2.5 μm) increasing the interest of their study on a sanitary point of view. Results showed really different NPAH and OPAH particle size distributions between both sites. At traffic site, clearly bimodal (notably for NPAHs) particle size distributions (Dp = 0.14 and 1.4 μm) were observed, while the particle size distributions were more scattered at the suburban site, especially for OPAHs. Bimodal particle size distribution observed at traffic site for the NPAH could be assigned to the vehicle emissions and the particle resuspension. Broadest distribution observed at the suburban site could be attributed to the mass transfer of compounds by volatilization/sorption processes during the transport of particles in the atmosphere. Results also showed that the combination of the study of particle size distributions applied to marker compounds (primary: 1-nitropyrene; secondary: 2-nitrofluoranthene) and to NPAH or OPAH chemical profiles bring some indications on their primary and/or secondary origin. Indeed, 1,4-anthraquinone seemed only primary emitted by vehicles while 7-nitrobenz[a]anthracene, benz[a]antracen7,12-dione and benzo[b]fluorenone seemed secondarily formed in the atmosphere.

scholarly journals Factors influencing particle size distributions in finely ground forage

1994 ◽  
Vol 74 (2) ◽  
pp. 383-385 ◽  
Author(s):  
R. Soofi-Siawash ◽  
G. W. Mathison
Keyword(s):  
Particle Size ◽  
Moisture Content ◽  
Particle Size Distribution ◽  
Key Words ◽  
Size Distribution ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Routine Procedure ◽  
Factors Influencing

Two studies were conducted to assess the possibility of using particle size distribution following grinding as a routine procedure of forage evaluation. It was concluded that although differences in particle size distribution could be detected when different feeds were ground, it would be difficult to standardize the technique since particle size distributions were influenced by type of mill used for grinding, particle size of forage before grinding, and moisture content of the forage. Key words: Forages, grinding, particle size, moisture, mill

scholarly journals COMPUTER SIMULATION OF RANDOM PACKINGS FOR SELF-SIMILAR PARTICLE SIZE DISTRIBUTIONS IN SOIL AND GRANULAR MATERIALS: POROSITY AND PORE SIZE DISTRIBUTION

Fractals ◽  
2014 ◽  
Vol 22 (03) ◽  
pp. 1440009 ◽  
Author(s):  
MIGUEL ANGEL MARTÍN ◽  
FRANCISCO J. MUÑOZ ◽  
MIGUEL REYES ◽  
F. JAVIER TAGUAS
Keyword(s):  
Computer Simulation ◽  
Particle Size ◽  
Pore Size Distribution ◽  
Pore Size ◽  
Size Distribution ◽  
Total Porosity ◽  
Size Distributions ◽  
Particle Size Distributions ◽  
Self Similar ◽  
Random Packings

A 2D computer simulation method of random packings is applied to sets of particles generated by a self-similar uniparametric model for particle size distributions (PSDs) in granular media. The parameter p which controls the model is the proportion of mass of particles corresponding to the left half of the normalized size interval [0,1]. First the influence on the total porosity of the parameter p is analyzed and interpreted. It is shown that such parameter, and the fractal exponent of the associated power scaling, are efficient packing parameters, but this last one is not in the way predicted in a former published work addressing an analogous research in artificial granular materials. The total porosity reaches the minimum value for p = 0.6. Limited information on the pore size distribution is obtained from the packing simulations and by means of morphological analysis methods. Results show that the range of pore sizes increases for decreasing values of p showing also different shape in the volume pore size distribution. Further research including simulations with a greater number of particles and image resolution are required to obtain finer results on the hierarchical structure of pore space.

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