Download or read book A Real time Fine Particulate Matter Monitor Based on Inertial Size separation and Optical Detection in a Microchannel written by Leon Ching Fung Yuen and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Real time Monitoring of Particulate Matter Size Concentration and Complex Index of Refraction written by Mir Seliman Waez and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation focuses on real-time monitoring of particulate matter concentration and sizing, and determining the complex index of refraction of single particles simultaneously. We investigated application of low-cost optical dust sensors GP2Y1010AU0F for monitoring of indoor air quality (IAQ) in buildings; developed a single-particle detector for large, non-absorbing spherical particles so the particles could be sized independently of the refractive index; and developed another sensor to determine the size and complex index of refraction of single particles simultaneously. We calibrated low-cost optical dust sensors GP2Y1010AU0F using an aerodynamic particle sizer (APS) as a reference instrument. Four sensors were connected in series with the APS and data were collected simultaneously on the downstream of a flow loop where the aerosol concentration was controlled. Sensors' performances were compared to each other as well as to the manufacturer's calibration data. Sensors were also exposed at two different positions in a controlled chamber to collect (1) indoor air data and (2) indoor air data with incense burning; results were compared to the calibration data. Initially, it was found that sensors' data were different from each other by ±15%. This percentage was decreased to ±5.9% by adjusting the potentiometer on each sensor. Since the sensors work with light scattering, it was found their outputs were affected by ambient light levels causing uncertainties in the measured values. Sensors' data for indoor air with incense burning were affected by airflow. When connected in series to the APS with 5 L/min airflow passing through them, their data agreed with the calibration data; however, they did not agree when exposed to still air i.e., without airflow. To determine the size of non-absorbing spherical particles independent of their refractive indices, we found the differential scattering cross-section to be only independent of the real refractive index at angles near 37 ± 5°. We built a device by modifying a Gaussian incident beam profile to a diamond-shaped beam so that the beam transit time of a particle passing through it could determine the true incident intensity for the scattering of the particle. By combining the modified Gaussian incident beam profile with detection of scattered light near 37 ± 5°, we demonstrated a refractive-index independent measurement of single spherical particles as they passed through the beam. In order to simultaneously determine the size and complex index of refraction of single particles, we developed a sensor that measures the scattered-light intensity of particles at three different scattering angles, i.e., 37 ± 5°, 80 ± 5°, and 115 ± 5°, in a diamond-shaped beam. The differential scattering cross-section is only independent of the real part of the refractive index at 37 ± 5°; however, in the case of absorbing particles, it depends on the imaginary part. At 115°, particles can be sized independently of the imaginary component; however, at 80°, it depends on both the real and the imaginary components. Although this dependence agrees at several angles, we have chosen 80° because the variation of the differential scattering cross-section at this angle is more consistent compared to other scattering angles.

Download or read book Laboratory Evaluation of Real time Smoke Particulate Monitors written by Anthony Trent and published by . This book was released on 2003 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: Describes the results of tests of new instruments that can be used to measure the particulate concentrations from forest fire smoke in real time. These instruments use the optical properties of light passed through air samples or other properties of sampled air to estimate particulate levels in real time. The new instruments included two samplers by MetOne Instruments, Inc., the E-BAM and the E-Sampler, and one by MIE, an improved version of the DataRAM4 monitor. All the instruments being tested were mounted side-by-side alongside a Federal Reference Method gravimetric sampler that was the standard all machines were judged against. Gravimetric samplers capture particulate that can be weighed to determine particulate concentration. Smoke was generated by burning beds of white pine needles in the burn chamber of the USDA Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory in Missoula. The E-BAM samplers overestimated smoke particulate by 13 percent compared to the Federal Reference Method sampler, but the four E-BAM samplers, results were within 12 percent of each other. The E-Samplersgas results were similar to each other. The new MIE DataRAM4 monitor has a particulate-size correction feature that should be enabled for the most accurate results. The DataRAM4 monitor overestimated particulate concentrations by 172 percent, but the results of the two machines tested were within 11 percent of each other. Earlier studies (Laboratory Evaluation of Two Optical Instruments for Real-Time Particulate Monitoring, 9925-2806-MTDC, and Evaluation of Optical Instruments for Real-Time Continuous Monitoring of Smoke Particulates, 0025-2860-MTDC) tested older instruments in the laboratory. Results of field tests of older instruments are reported in Real-Time Smoke Particulate Sampling, Fire Storm 2000 (0125-2832-MTDC).

Download or read book Comparison of Real Time Instruments Used to Monitor Airborne Particulate Matter written by Albert Chung and published by . This book was released on 2000 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Laboratory Evaluation of Two Optical Instruments for Real time Particulate Monitoring of Smoke written by and published by . This book was released on 1999 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Correlation of the Fibrous Aerosol Monitor with the Optical Membrane Filter Count Technique written by Steven J. Page and published by . This book was released on 1980 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Fine Particulate Matter Monitoring Technologies written by Elisa Eiseman and published by . This book was released on 1997 with total page 50 pages. Available in PDF, EPUB and Kindle. Book excerpt: Measurement of ambient particulate matter (PM) mass and chemical composition is important for source attribution, studies of health and welfare effects, and determination of compliance with standards. A comprehensive approach to PM monitoring requires a combination of analytical techniques to assess mass and chemical composition, and an integrated network of ambient and stack/source PM monitors. There are several commercially available devices that can continuously monitor PM mass. However, none of these methods have been approved by the EPA, since most of these devices do not directly measure mass. In addition, chemical analysis of PM is costly and difficult, since existing technologies are not capable of continuous sampling/monitoring for chemical composition. Therefore, the next generation of PM monitors should be multi-functional instruments capable of continuous, real-time monitoring of both PM mass and chemical composition. In addition, they will need to address several barriers to their use including cost, complicated calibration and verification systems, and cumbersome installation and maintenance procedures.

Download or read book Low cost Air Particulate Monitor Based on Particle Capture and Imaging written by An Chang (S.M.) and published by . This book was released on 2018 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt: Particulate Matter (PM) pollution continues to be an important global environmental issue and raises increasing concerns for public health. The strong correlation between personal health impact and actual local exposure creates a huge demand for air particulate sensors meant for small-scale measurement. However, today's air particulate monitoring technologies suffer from high cost, high power requirements, or large size, which presents an opportunity to create low-cost, compact, and low-power sensors that are desired for block-level, household, automobile, or even personal-level monitoring. In this thesis, the basic concept components of a novel PM monitoring method based on capture and imaging are developed and validated. Two capture techniques, electrostatic precipitation (ESP) and fiber-filtration, are demonstrated and verified with corresponding imaging results. Particulates captured either on flat substrate or aligned fibers are illuminated by LED light source with a glancing angle, or with the help of waveguides. Light scattered from the particles is detected by a CMOS camera module, yielding the particle size distribution and also revealing the morphology and properties of particulates. The results suggest that, with proper data analysis, this approach has the potential to monitor the real-time PM level of the sampled air and also classify between different particle sources. A detection limit of 200 nm is demonstrated and two kinds of pollens are notably distinguished from solid dust particulates. Additional, assorted replenishment schemes are designed to ensure a long, maintenance-free operational life.

Download or read book Mobile Airborne Particulate Matter Monitor for Deployment Over a Cellular Network written by Alexander William Elium and published by . This book was released on 2007 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Recent Advances in Low cost Particulate Matter Sensor written by Jiayu Li (Environmental engineer) and published by . This book was released on 2019 with total page 363 pages. Available in PDF, EPUB and Kindle. Book excerpt: Particulate matter (PM) has been monitored routinely due to its negative effects on human health and atmospheric visibility. Standard gravimetric measurements and current commercial instruments for field measurements are still expensive and laborious. The high cost of conventional instruments typically limits the number of monitoring sites, which in turn undermines the accuracy of real-time mapping of sources and hotspots of air pollutants with insufficient spatial resolution. The new trends of PM concentration measurement are personalized portable devices for individual customers and networking of large quantity sensors to meet the demand of Big Data. Therefore, low-cost PM sensors have been studied extensively due to their price advantage and compact size. These sensors have been considered as a good supplement of current monitoring sites for high spatial-temporal PM mapping. However, a large concern is the accuracy of these low-cost PM sensors.Multiple types of low-cost PM sensors and monitors were calibrated against reference instruments. All these units demonstrated high linearity against reference instruments with high R2 values for different types of aerosols over a wide range of concentration levels. The question of whether low-cost PM monitors can be considered as a substituent of conventional instruments was discussed, together with how to qualitatively describe the improvement of data quality due to calibrations. A limitation of these sensors and monitors is that their outputs depended highly on particle composition and size, resulting in as high as 10 times difference in the sensor outputs.Optical characterization of low-cost PM sensors (ensemble measurement) was conducted by combining experimental results with Mie scattering theory. The reasons for their dependence on the PM composition and size distribution were studied. To improve accuracy in estimation of mass concentration, an expression for K as a function of the geometric mean diameter, geometric standard deviation, and refractive index is proposed. To get rid of the influence of the refractive index, we propose a new design of a multi-wavelength sensor with a robust data inversion routine to estimate the PM size distribution and refractive index simultaneously.The utility of the networked system with improved sensitivity was demonstrated by deploying it in a woodworking shop. Data collected by the networked system was utilized to construct spatiotemporal PM concentration distributions using an ordinary Kriging method and an Artificial Neural Network model to elucidate particle generation and ventilation processes. Furthermore, for the outdoor environment, data reported by low-cost sensors were compared against satellite data. The remote sensing data could provide a daily calibration of these low-cost sensors. On the other hand, low-cost PM sensors could provide better accuracy to demonstrate the microenvironment.

Download or read book Indoor Aerosol Sensing and Resuspension Dynamics written by Parichehr Salimifard and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Exposure to indoor particulate matter (PM) is associated with adverse health effects. Controlling the indoor PM exposure relies on an accurate understanding of aerosol transport, as well as accurate real-time monitoring of PM concentration level in the indoor environment. Indoor aerosol transport is a cycle involving continuous repetitions of deposition and resuspension of particles from indoor surfaces. Occupants activities such as walking, and indoor environmental conditions such as relative humidity (RH), influence the resuspension rate of particles. The first objective of this dissertation was to investigate the effects of RH and turbulent air swirls on the resuspension rate of allergen carrier particles from indoor surfaces. This study shows that increasing RH can reduce the resuspension and spread of hydrophilic particles such as dust mites and that the presence of carpet significantly increased resuspension rates compared to linoleum flooring surfaces.This study also analyzes the efficacy of indoor PM sensing with current technologies. Effective PM removal strategies depend on continuous monitoring of indoor aerosols. Although PM monitoring in buildings has not been feasible due to high PM sensor cost, the recent advent of low-cost optical PM sensors has enabled real-time PM monitoring with high spatiotemporal resolution. Since biological particles such as dust mites, pollen, and pet dander are linked to respiratory and allergic symptoms among building occupants, PM sensors can be utilized to accurately measure bioaerosols. However, the performance of low-cost particle sensors in monitoring bioaerosols is under-investigated. Thus, the second objective of this dissertation was to evaluate the performance of low-cost optical particle counters (OPC) in monitoring the common indoor bioaerosols. Controlled chamber experiment results showed that low-cost OPCs performance is strongly influenced by particle concentrations being measured. Low-cost OPCs did not show a linear response compared to the reference sensor in the concentration range less than 5/cm3 for measuring PM2.5 bioaerosol concentrations, while the tested sensors exhibited more linear responses in the range greater than 5/cm3. For each low-cost OPC, particle-specific, as well as average linear calibration equations that work well for the aggregate of tested bioaerosols, were developed.One of the challenges in particle monitoring is size characterization due to the variable and irregular shapes. Usually, for application purposes, particles are assumed to be perfect spheres with corresponding spherical physical behaviors and properties. The general process typically defines a sphere with similar physical properties and assigns it an equivalent diameter size. Aerodynamic equivalent diameter is the most commonly used particle size. While aerodynamic size characterization is required for PM transport and exposure studies, optical-based sensors are used in place of aerodynamic-based sensing in most field applications. The validity of such practice has been called into question by previous studies and further investigation of the relationship between aerodynamic and optical size measurement is necessary. Consequently, the third objective of this dissertation was to experimentally compare the size-resolved concentration measurements of an aerodynamic particle sizer with an optical particle counter. Comparison of multiple tests with sixteen -monodisperse and polydisperse, biological and non-biological- particles showed that the particle type, size, and the measurement size fraction affect the relationship between the two PM sensing techniques. Accordingly, particle type and size-resolved specific empirical linear calibration curves between the two sensors for size fractions of smaller than 10 m, smaller than 2.5 m, and total number counts were provided. These calibrations provide an opportunity for real-world application of current technologies to reduce the PM exposure health risks for the public.

Download or read book Study and Design of MEMS Microbalances for Bioaerosol Detection in Indoor Environments written by Uğur Soysal and published by . This book was released on 2019 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microfabrication methods are an emerging technology which enables to build micro scale airborne particle mass concentration measurement systems. A personal airborne particle monitoring system can be achieved by combining an appropriate sampling method with inertial micro-electromechanical systems (MEMS) mass sensors. While aerosol sampling methods can take airborne particles from ambient air and transport to a detector in the most efficient way, MEMS provide the detection and estimation of the mass based on a shift in the resonance frequency of oscillating sensors.In this context, an extensive literature review is proposed in order to examine the mass concentration measurement methods from past to present. The methodological tendencies for advanced real-time aerosol mass concentration measurement are evaluated. Finally, bulk-mode silicon-based MEMS mass sensor is chosen to be coupled with an appropriate aerosol sampler.Following that the miniaturization possibilities of aerosol sampling methods are discussed and inertial impactor is chosen as a suitable aerosol sampling method. Then, the impactor is designed, fabricated, and characterized based on the classical impaction theory. The latter, the deposition characteristics of monodisperse aerosol (fluorescent) and bioaerosols (Aspergillus niger, Staphylococcus epidermidis, Pseudomonas fluorescens) are explored by inertial impaction on silicon and nanostructured silicon (i.e. black silicon). The empirical results show that the size of airborne particles plays a key role to determine the deposition characteristics of the impaction by the mechanism of rebound and re-entrainment (i.e. bounce effect) of the particles.In the context of developing an inertial mass sensor, sub-μm air gap MEMS mass sensors have been successfully fabricated based on the thick oxide as a mask layer method. This method enables to fabricate high-aspect-ratio air-gap MEMS resonators. Then, the devices are electrically characterized and the mass resolution is investigated. As a result, high-aspect-ratio MEMS sensors are operated in two different bulk modes (Lamé and extensional modes) and the mass resolution of the sensors is found to be as sub-ng.Finally, the fabricated MEMS mass sensors are integrated into the developed impactor and monodisperse fluorescent particles are successively impacted on the sensors. The shift in the resonance frequency of MEMS mass sensors are evaluated based on Sauerbrey's principle. Ultimately, MEMS mass sensors have achieved to detect and perform mass measurements of the impacted fluorescent particles with a promising precision. Although more impactions are needed to calibrate the sensors, the theoretical mass sensitivity of the device is matched with the experimental mass sensitivity obtained from successive impactions. Therefore, the developed airborne particle detection system paves the way for real-time detection and mass measurements of aerosol and bioaerosols.

Download or read book Development of New Generation Personal Monitors for Fine Particulate Matter PM and Its Metal Content written by Constantinos Sioutas and published by . This book was released on 2004 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Laboratory Evaluation of Two Optical Instruments for Real Time Particulate Monitoring of Smoke Classic Reprint written by Andy Trent and published by Forgotten Books. This book was released on 2019-01-13 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: Excerpt from Laboratory Evaluation of Two Optical Instruments for Real-Time Particulate Monitoring of Smoke A series of field tests should be conducted using optical instruments and gravimetric instruments. Setting up the instruments adjacent to a relatively large prescribed burn would provide a realistic comparison. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.

Download or read book Development of a Low Cost Particulate Matter Monitor written by and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: We describe a small, inexpensive portable monitor for airborne particulates, composed of the following elements: a. A simple size-selective inlet (vertical elutriator) that permits only particles below a pre-set diameter to pass and enter the measurement section; b. A measurement section in which passing particles are deposited thermophoretically on a micro-fabricated resonant piezoelectric mass sensor; c. An optical characterization module co-located with the mass sensor module that directs infrared and ultraviolet beams through the deposit. The emergent optical beams are detected by a photodiode. The optical absorption of the deposit can be measured in order to characterize the deposit, and determine how much is due to diesel exhaust and/or environmental tobacco smoke; and d. A small pump that moves air through the device, which may also be operated in a passive mode. The component modules were designed by the project team, and fabricated at UCB andLBNL. Testing and validation were performed in a room-sized environmental chamber at LBNL in to which was added either environmental tobacco smoke (ETS, produced by a cigarette smoking machine) or diesel exhaust (from a conventional diesel engine). Two pilot field tests in a dwelling compared the monitor with existing aerosol instruments during exposure to infiltrated ambient air to which cigarette smoke, diesel exhaust, wood smoke and cooking fumes were added. The limit of detection (LOD) derived from statistical analysis of field data is 18 mu g m-3, at the 99percent confidence level. The monitor weighs less than 120 g and has a volume of roughly 250 cm3. Power consumption is approximately 100 milliwatts. During this study, the optical component of the device was not fully implemented and has been left for future efforts. Suggested improvements in the current prototype include use of integrated thermal correction, reconfiguration of the resonator for increased particle collection area, increased thermophoretic collection efficiency using an increased temperature gradient, and shielding the resonator electronics from deposition of ultrafine particles.

Download or read book Airborne Particles written by National Research Council (U.S.). Subcommittee on Airborne Particles and published by . This book was released on 1979 with total page 376 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Transport and Size separation of Airborne Particles in a Microchannel for Continuous Particle Monitoring written by Allison Schaap Schaap and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: