Single Particle Characterization Of Soil And Dust Particulate Matter In The Urban And Marine Environments

Author : Srikar Velagapudi
Publisher :
ISBN 13 :
Total Pages : 105 pages
Book Rating : 4.:/5 (11 download)

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Download or read book Examination of Fine Particulate Matter Inside Farm Houses Located Near Biosolids Applied Fields written by Srikar Velagapudi and published by . This book was released on 2017 with total page 105 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present research comprehensively examined the morphology and elemental composition of fine particulate matter (PM) and identified potential sources of these elements in six farm houses located in Ohio. Also, an integrated predictive model was developed and evaluated for estimating the deposition of particulate matter in the farm houses as a result of the spread of biosolids on nearby farm fields. In order to study the particulate matter inside the farmhouse, two field studies were carried out during the summers of 2010 and 2011. These field studies were done at six different houses located in the proximate range of agricultural fields out of which three were study houses and the remaining three were control houses. The particulate concentrations were monitored both inside and outside the house simultaneously using Grimm Dustmonitor and DustTrak instruments. In this process, the particles were also collected on the filter paper placed in the Dustmonitor for detailed characterization of PM. Scanning electron microscopy (SEM) in combination with energy dispersive spectroscopy (EDS) was used to analyze the particles deposited on the filter paper. The analysis helped in characterizing PM collected outside and inside the house and in understanding the effect of the distance between field and house along with examining the relationship between characteristics of PM indoors and outdoors. The morphological properties of particles such as diameter, area, perimeter, aspect ratio, and shape factor of particles were determined using Image J software for the images captured using SEM. It was observed that there were a majority of particles in the range of 2.5 to 5 μm on all filter papers except two. The average PM2.5 (particulate matter with less than 2.5 μm diameter) over eight filters was observed to be about 32%, while for the ranges of 2.5 to 5.0 μm and 5.0 to 10.0 μm the averages were about 38% and 20%, respectively. The PM2.5 averages for smoking, nonsmoking, control houses, and study houses were observed to be 40.63%, 28.86%, 33.37% and 31.28% respectively. The shape factor distribution and shape distribution results indicate that there was a higher percentage of agglomerates, which was followed by spherical and pentagonal shaped particles. It was estimated, that on an average, 37.79% of overall PM collected on all the eight filters were agglomerates, while 28.28% were spherical in shape. Additionally, the source contributions were evaluated using a positive matrix factorization (PMF) tool developed by the United States Environmental Protection Agency (US EPA). Initially, filter papers collected inside and outside houses were analyzed using inductively coupled plasma mass spectrometry (ICP-MS) for estimating the concentrations of the elements. The US EPA-regulated elements such as arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), nickel (Ni), selenium (Se), and titanium (Ti) were observed to be at higher levels near study houses relatively when compared to control houses. The contributions of these US EPA regulated elements were affected when the average concentrations were estimated by fusing both study and control houses. It was discovered that the key sources contributing were industrial, soil/dust, biosolids, and ambient/background sources outside houses, while an additional indoor source was identified when executing the PMF tool with samples from inside houses. Industrial and soil/dust sources were recognized to be major contributors for most of the elements. The study uncovered that the elemental concentrations inside and outside houses does not have a significant impact due to biosolids. Soil/dust in combination with ventilation settings played a key role in contributing to the higher concentrations of the elements inside houses. The study developed an integrated predictive model by amalgamating an area source model for predicting ambient concentrations outside the house, a single compartment mass balance model for estimating indoor concentrations, and a new analytical particle deposition model. An integrated predictive model was applied to estimate the deposition of particles inside the house for various stability classes increased for varying emission rates representing different spread rates of biosolids on the farm field. The study found that the deposition of particles for ambient stable conditions was approximately 70% of ambient unstable atmospheric conditions. The single compartment mass balance model evaluation gives rise to the reasoning that predicted concentrations inside the house were relatively close to observed concentrations for lower (0.23 to 0.9 μm) and higher size (>7.5 μm) particles. It was concluded from the model evaluation results that the predicted concentrations of particulate matter in the range of 0.9 to 7.5 μm were not in agreement with the observed concentrations. The significant interpretation made about the model is that the predominant factor impacting predicted concentrations is the ambient concentration at the start of the day (time, t=0).