Download or read book Single Particle Characterization Source Apportionment and Aging Effects of Ambient Aerosols in Southern California written by Laura Grace Shields and published by ProQuest. This book was released on 2008 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: Composed of a mixture of chemical species and phases and existing in a variety of shapes and sizes, atmospheric aerosols are complex and can have serious influence on human health, the environment, and climate. In order to better understand the impact of aerosols on local to global scales, detailed measurements on the physical and chemical properties of ambient particles are essential. In addition, knowing the origin or the source of the aerosols is important for policymakers to implement targeted regulations and effective control strategies to reduce air pollution in their region. One of the most ground breaking techniques in aerosol instrumentation is single particle mass spectrometry (SPMS), which can provide online chemical composition and size information on the individual particle level. The primary focus of this work is to further improve the ability of one specific SPMS technique, aerosol time-of-flight mass spectrometry (ATOFMS), for the use of identifying the specific origin of ambient aerosols, which is known as source apportionment. The ATOFMS source apportionment method utilizes a library of distinct source mass spectral signatures to match the chemical information of the single ambient particles. The unique signatures are obtained in controlled source characterization studies, such as with the exhaust emissions of heavy duty diesel vehicles (HDDV) operating on a dynamometer. The apportionment of ambient aerosols is complicated by the chemical and physical processes an individual particle can undergo as it spends time in the atmosphere, which is referred to as "aging" of the aerosol. Therefore, the performance of the source signature library technique was investigated on the ambient dataset of the highly aged environment of Riverside, California. Additionally, two specific subsets of the Riverside dataset (ultrafine particles and particles containing trace metals), which are known to cause adverse health effects, were probed in greater detail. Finally, the impact of large wildfires on the ambient levels of particulate matter in Southern California is discussed. The results of this work provide insight into single particles impacting the Southern California region, the relative source contributions to this region, and finally an examination of how atmospheric aging influences the ability to perform source apportionment.

Download or read book Anthropogenic Particulate Source Characterization and Source Apportionment Using Aerosol Time of flight Mass Spectrometry written by Stephen Mark Toner and published by . This book was released on 2007 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt: Methods of measuring the chemical and physical properties of aerosols as well as proper source apportionment of ambient particles are necessary to provide insight as to the roles they play in the environment and their impact on human health. In addition, the ability to apportion ambient particles quickly and accurately will be very helpful for environmental and health agencies and for monitoring and enforcing emission standards by allowing such agencies to determine the primary source of aerosols in their monitoring areas. The goal of this dissertation is to provide a new approach for aerosol source apportionment using aerosol time-of-flight mass spectrometry (ATOFMS) single particle data. This goal was accomplished by determining unique mass spectral signatures for specific aerosol sources and by developing these signatures into a source signature library in which ambient ATOFMS data can be matched and apportioned. The creation of the source signature library (SSL) began with the characterization of specific sources themselves. Heavy duty diesel vehicle (HDDV) emissions were characterized using ATOFMS from a dynamometer study. The particle types detected for HDDVs were compared to those from a previous dynamometer study of gasoline powered light duty vehicles (LDV) to see if HDDV and LDV particles can be distinguished. A SSL was then created for the HDDV and LDV emissions to test the ability to properly apportion between the two sources on ambient ATOFMS data collected next to a major freeway using a SSL matching technique. This work demonstrated that the two sources are readily distinguishable in a fresh emission environment, and that the matching method is a valid means for apportioning ATOFMS data. The SSL was then extended for multiple specific sources as well as for non-source specific particles and was used to apportion the same freeway study particles; showing that the source matching method is able to accurately distinguish different particle sources and that there can be a large contribution from sources other than vehicles near a major freeway. Lastly, the SSL matching method was used to apportion ambient aerosols for two major non-US cities to show that the SSL matching technique is applicable to worldwide ambient ATOFMS data.

Download or read book Extending the Physicochemical Characterization of Aerosol Particles in California written by Melanie Dorothy Zauscher and published by . This book was released on 2012 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerosols affect the radiative balance of earth, alter cloud formation, and adversely impact human health. Knowledge of the physicochemical properties of particles, which can rapidly change, is essential to predict and mitigate their negative impacts. Hence, in-situ measurements of single-particle composition and physical properties are needed. Aerosol time-of-flight mass spectrometry (ATOFMS), which measures the size-resolved chemical mixing state of individual particles, was used to study aerosols at different locations in California. Soot particles internally mixed with soluble ammonium, nitrate, and sulfate transported from the Central Valley were found to be a major source of cloud condensation nuclei in the Sierra Nevada during winter 2010, never identified before. These aged soot particles may be affecting regional cloud microphysics and potentially precipitation. Rapid aging of biomass burning aerosols during intense urban fires were analyzed for the first time via single-particle mass spectrometry throughout the 2007 San Diego Wildfires. Furthermore, estimated size-resolved mass concentrations of particulate matter during the wildfires showed for the first time that particles

Download or read book Determination of the spatial and temporal variability of size resolved PM2 5 composition and mixing state in multiple regions in California written by Kimberly Prather and published by California Air Resources Board. This book was released on 2009-12-01 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: Final report for California Air Resources Board contract 04-336. For an abstract and link to full text, please see: http://www.arb.ca.gov/research/single-project.php?row_id=64974

Download or read book Chemical Characterization and Source Apportionment of Size Fractionated Atmospheric Aerosols and Evaluating Student Attitudes and Learning in Large Lecture General Chemistry Classes written by Greg Harold Allen and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Chemical speciation and source apportionment of size fractionated atmospheric aerosols were investigated using laser desorption time-of-flight mass spectrometry (LD TOF-MS) and source apportionment was carried out using carbon-14 accelerator mass spectrometry (14C AMS). Sample collection was carried out using the Davis Rotating-drum Unit for Monitoring impact analyzer in Davis, Colfax, and Yosemite, CA. Ambient atmospheric aerosols collected during the winter of 2010/11 and 2011/12 showed a significant difference in the types of compounds found in the small and large sized particles. The difference was due to the increase number of oxidized carbon species that were found in the small particles size ranges, but not in the large particles size ranges. Overall, the ambient atmospheric aerosols collected during the winter in Davis, CA had and average fraction modern of F14C = 0.753 ± 0.006, indicating that the majority of the size fractionated particles originated from biogenic sources. Samples collected during the King Fire in Colfax, CA were used to determine the contribution of biomass burning (wildfire) aerosols. Factor analysis was used to reduce the ions found in the LD TOF-MS analysis of the King Fire samples. The final factor analysis generated a total of four factors that explained an overall 83% of the variance in the data set. Two of the factors correlated heavily with increased smoke events during the sample period. The increased smoke events produced a large number of highly oxidized organic aerosols (OOA2) and aromatic compounds that are indicative of biomass burning organic aerosols (WBOA). The signal intensities of the factors generated in the King Fire data were investigated in samples collected in Yosemite and Davis, CA to look at the impact of biomass burning on ambient atmospheric aerosols. In both comparison sample collections the OOA2 and WBOA factors both increased during biomass burning events located near the sampling sites. The correlation between the OOA2 and WBOA factors and smoke levels indicates that these factors can be used to identify the influence of biomass burning on ambient aerosols. The effectiveness of using the ChemWiki instead of a traditional textbook was investigated during the spring quarter of 2014. Student performance was measured using common midterms, a final, and a pre/post content exams. We also employed surveys, the Colorado Learning Attitudes about Science Survey (CLASS) for Chemistry, and a weekly time-on-task survey to quantify students' attitudes and study habits. The effectiveness of the ChemWiki compared to a traditional textbook was examined using multiple linear regression analysis with a standard non-inferiority testing framework. Results show that the performance of students in the section who were assigned readings from the ChemWiki was non-inferior to the performance of students in the section who were assigned readings from the traditional textbook, indicating that the ChemWiki does not substantially differ from the standard textbook in terms of student learning outcomes. The results from the surveys also suggest that the two classes were similar in their beliefs about chemistry and overall average time spent studying. These results indicate that the ChemWiki is a viable cost-saving alternative to traditional textbooks. The impact of using active learning techniques in a large lecture general chemistry class was investigated by assessing student performance and attitudes during the fall 2014 and winter 2015 quarters. One instructor applied active learning strategies while the remaining instructors employed more traditional lecture styles. Student performance, learning, learning environments, and attitudes were measured using a standardized pre/post exams, common final exams, classroom observations, and the CLASS chemistry instrument in large lecture general chemistry courses. Classroom observation data showed that the active learning class was the most student centered and of the other classes two instructors were transitional in their teaching style and the remaining two primarily employed traditional lecture techniques. The active learning class had the highest student performance but the difference was only statistically significant when compared to the two traditional lecture classes. Overall, our data showed a trend that student performance increased as the instructional style became more student centered. Student attitudes didn't seem to correlate with any specific instructional style and the students in the active learning class had similar attitudes to the other general students. The active learning class was successful in increasing the average time students spent studying outside of the class, a statistically significant difference of about 1.5 to 3.0 hrs/week.

Download or read book Analysis of Atmospheric Aerosol Processes Using Single Particle Mass Spectrometry written by Jeffrey Robert Whiteaker and published by . This book was released on 2002 with total page 644 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dissertation Abstracts International written by and published by . This book was released on 2008 with total page 800 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characterization of Ambient Aerosol Source and Processes During CalNex 2010 with Aerosol Mass Spectrometry written by José Luis Jiménez and published by . This book was released on 2013 with total page 124 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Measurement Analysis and Remediation of Environmental Pollutants written by Tarun Gupta and published by Springer Nature. This book was released on 2019-10-08 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book discusses contamination of water, air, and soil media. The book covers health effects of such contamination and discusses remedial measures to improve the situation. Contributions by experts provide a comprehensive discussion on the latest developments in the detection and analysis of contaminants, enabling researchers to understand the evolution of these pollutants in real time and develop more accurate source apportionment of these pollutants. The contents of this book will be of interest to researchers, professionals, and policy makers alike.

Download or read book Source Profiling and Apportionment of Airborne Particles written by Philip Joseph Silva and published by . This book was released on 2000 with total page 904 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Studies of Ambient Organic and Inorganic Aerosol in Southern California written by Joseph James Ensberg and published by . This book was released on 2014 with total page 494 pages. Available in PDF, EPUB and Kindle. Book excerpt: The negative impacts of ambient aerosol particles, or particulate matter (PM), on human health and climate are well recognized. However, owing to the complexity of aerosol particle formation and chemical evolution, emissions control strategies remain difficult to develop in a cost effective manner. In this work, three studies are presented to address several key issues currently stymieing California's efforts to continue improving its air quality. Gas-phase organic mass (GPOM) and CO emission factors are used in conjunction with measured enhancements in oxygenated organic aerosol (OOA) relative to CO to quantify the significant lack of closure between expected and observed organic aerosol concentrations attributable to fossil-fuel emissions. Two possible conclusions emerge from the analysis to yield consistency with the ambient organic data: (1) vehicular emissions are not a dominant source of anthropogenic fossil SOA in the Los Angeles Basin, or (2) the ambient SOA mass yields used to determine the SOA formation potential of vehicular emissions are substantially higher than those derived from laboratory chamber studies. Additional laboratory chamber studies confirm that, owing to vapor-phase wall loss, the SOA mass yields currently used in virtually all 3D chemical transport models are biased low by as much as a factor of 4. Furthermore, predictions from the Statistical Oxidation Model suggest that this bias could be as high as a factor of 8 if the influence of the chamber walls could be removed entirely. Once vapor-phase wall loss has been accounted for in a new suite of laboratory chamber experiments, the SOA parameterizations within atmospheric chemical transport models should also be updated. To address the numerical challenges of implementing the next generation of SOA models in atmospheric chemical transport models, a novel mathematical framework, termed the Moment Method, is designed and presented. Assessment of the Moment Method strengths and weaknesses provide valuable insight that can guide future development of SOA modules for atmospheric CTMs. Finally, regional inorganic aerosol formation and evolution is investigated via detailed comparison of predictions from the Community Multiscale Air Quality (CMAQ version 4.7.1) model against a suite of airborne and ground-based meteorological measurements, gas- and aerosol-phase inorganic measurements, and black carbon (BC) measurements over Southern California during the CalNex field campaign in May/June 2010. Results suggests that continuing to target sulfur emissions with the hopes of reducing ambient PM concentrations may not the most effective strategy for Southern California. Instead, targeting dairy emissions is likely to be an effective strategy for substantially reducing ammonium nitrate concentrations in the eastern part of the Los Angeles Basin.

Download or read book Single Particle Perspective on the Southern California Ozone Study written by Sylvia Harriet Pastor and published by . This book was released on 2003 with total page 1244 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Single Particle Analysis of Transient Variations Occurring in Atmospheric Aerosols written by Christopher Alan Noble and published by . This book was released on 1999 with total page 1230 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Interpretation of Mass Spectra written by Fred Warren McLafferty (Chemiker, USA) and published by . This book was released on 1973 with total page 278 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Air Quality in the Mexico Megacity written by L. Molina and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 401 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this book, experts in atmospheric sciences, human health, economics, social and political sciences contribute to an integrated assessment of the complex elements needed to structure air quality policy in the 21st century. The analysis is developed through a case study of the Mexico City Metropolitan Area - one of the world's largest megacities in which air pollution grew unchecked for decades. The international research team is led by Luisa T. and Mario J. Molina, Nobel Laureate in Chemistry. Improvements in Mexico City's air quality in the last decade testifies to the power of determined and enlightened policy making, and throws into relief the tough problems that remain to be solved. The volume's first six chapters, including the contributions of over 50 distinguished scholars from Mexico and the US, outline the fundamental areas of knowledge policy makers must accommodate. The message is that only good science and well-chosen technologies can direct the way to corrective regulatory measures; but without strong commitment from government, no amount of science or technology can help.

Download or read book New Insights Into Single particle Mixing State Using Aircraft Aerosol Time of flight Mass Spectrometry written by Kerri Anne Pratt and published by . This book was released on 2009 with total page 387 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atmospheric aerosols strongly influence the energy balance of the Earth and the hydrological cycle by scattering and absorbing radiation and acting as cloud condensation and ice nuclei. The climate and human health impacts of aerosols are strongly dependent on particle size, chemical composition, and mixing state. During transport in the atmosphere, aerosol particles undergo physical and chemical transformations (atmospheric aging) through heterogeneous reactions with trace gases and gas-particle partitioning of semivolatile species. The size-resolved chemical composition of individual particles may be examined in real-time using aerosol time-of-flight mass spectrometry (ATOFMS). A smaller ATOFMS with increased data acquisition capabilities was developed for aircraft-based studies. Particle volatility was examined through ground-based measurements during the Study of Organic Aerosols in Riverside, CA (SOAR), and vertical mixing state profiles and cloud residues were examined through flight-based measurements during the Ice in Clouds Experiment - Layer Clouds (ICE-L). An automated thermodenuder (TD) was coupled to the aircraft (A)-ATOFMS to provide the first real-time, individual-particle size and volatility-resolved chemical composition measurements. This work provided insight into the volatility of secondary species, as well as the sources and chemistry of ambient particle cores. Seasonal differences in the volatility of amine species were attributed to the formation of aminium sulfate and nitrate salts in the summer. Oligomeric species were detected in real-time for the first time in individual ambient aerosol particles; increased oligomer ion intensities were associated with increased particle acidity and heating. During ICE-L, vertical profiles of particle types, such as soot, mixed with secondary species, such as sulfuric acid, were examined. For cloud sampling, a counterflow virtual impactor was utilized in series with the A-ATOFMS to examine the residues of cloud droplets and ice crystals. This resulted in the first in-situ detection of biological particles in high altitude ice clouds influenced by long-range transported dust. Playa salts were observed to serve as cloud condensation nuclei and were preferentially observed as residues of large droplets.

Download or read book Characterization of Ambient Automobile and Diesel Aerosols Utilizing Aerosol Time of Flight Mass Spectrometry written by David Alan Sodeman and published by . This book was released on 2004 with total page 508 pages. Available in PDF, EPUB and Kindle. Book excerpt: