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 Using Aerosol Time of flight Mass Spectrometry ATOFMS Data to Gain New Insights Into the Temporal Profiles Composition and Evolution of Individual Particles in the Troposphere written by Don-Yuan Liu and published by . This book was released on 2000 with total page 608 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Understanding the Chemistry of Atmospheric Particles Using Single Particle Mass Spectrometry written by Maria Anna Zawadowicz and published by . This book was released on 2017 with total page 219 pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis explores ways in which single particle mass spectrometry can be extended, whether through hardware improvements, or through the use of advanced data processing techniques to provide new kinds of aerosol chemistry measurements. Most of this work has been carried out using the Particle Analysis by Laser Mass Spectrometry (PALMS) instrument, an aircraft deployable mass spectrometer that uses intense (~10^9 Wcm^-2 ) UV laser pulses to vaporize and ionize single particles and measures their mass spectra using a time-of-flight mass spectrometer. Near-term and long-term hardware improvements as well as advanced data analysis techniques are explored in order to extract new chemical information from the thus obtained single particle mass spectra. Hardware improvements to PALMS are explored, such as the use of a high-powered femtosecond laser to obtain single particle mass spectra and a new high resolution compact mass analyzer. Also, a new commercial mass spectrometer LAAPToF is characterized and compared to PALMS. In addition to hardware improvements, novel data analysis techniques for analysis of single particle mass spectra were developed as a part of this work. In particular, a new method to identify biologically-derived particles is presented and used to derive vertical profiles of bioaerosol from near-surface to the upper troposphere.

Download or read book New Approaches for the Chemical and Physical Characterization of Aerosols Using a Single Particle Mass Spectrometry Based Technique written by Matthew Todd Spencer and published by . This book was released on 2007 with total page 229 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comparison of mass spectra generated from petrochemical particles was made to light duty vehicle (LDV) and heavy duty diesel vehicle (HDDV) particle mass spectra. This comparison has given us new insight into how to differentiate between particles from these two sources.

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 Novel Techniques and Applications in Single Particle Mass Spectrometry written by John Francis Cahill and published by . This book was released on 2014 with total page 419 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the environment, aerosol particles can affect climate directly though scattering and absorbing radiation and indirectly by influencing cloud formation, albedo, and lifetime. Beyond the environment, aerosols are commonly used as a delivery mechanism for a variety of products, such as inhalers and spray paints. Chemically characterizing aerosols is a difficult endeavor, and relatively few instrumental methods are capable of doing so. A unique subset of instrumentation and techniques exist to measure aerosol chemical and physical properties. Among these, the aerosol time-of-flight mass spectrometer (ATOFMS) can measure single particle chemistry and size in real time. The ATOFMS was developed for the study atmospheric aerosols, and data acquired by the ATOFMS over the years since its creation has provided significant insight into many atmospheric phenomena; however, the application of this technique into disciplines other than atmospheric chemistry has been relatively unexplored. In this dissertation the ATOFMS is used in a conventional sense, to provide insight into atmospheric particle chemistry through two field studies in California, but also in an unconventional way by using the ATOFMS to answer outstanding questions in other disciplines, including nanomaterials and biochemistry. Often the chemistry of a single unit, rather than of the bulk, is needed in these disciplines, and the ATOFMS is uniquely suited to provide this information. The ATOFMS was used to chemically characterize single particles of a unique class of nanomaterials, called metal organic frameworks (MOFs), comprised of functionalized organic linkers and metal ions or metal ion clusters. ATOFMS data was able to show the presence of MOFs with mixed functionality, and show the exchange of functional groups between materials. Cell processes can be monitored by measuring small molecules that are part of cell metabolism, which can provide insight into cell functions, environment, and disease. Using an ATOFMS with a modified aerodynamic lens inlet, single microalgae cells 4-10 μm in diameter of various types have been be characterized. Compared to other single cell mass spectrometry techniques, the modified ATOFMS has unprecedented throughput, up to 50 Hz. Time-resolved measurements of cells undergoing nitrogen deprivation further highlight the abilities of the technique for single cell analysis.

Download or read book Advances and Applications of Mass Spectral Techniques for the Characterization of Atmospheric Aerosol Particles written by Lindsay Erighn Hatch and published by . This book was released on 2012 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerosol particles are ubiquitous in the atmosphere and induce significant impacts on human health and climate that depend on their physical and chemical properties, such as size, composition, and mixing state (chemical associations). Measurements of aerosol composition at the single-particle level are necessary to better understand these effects. Aerosol time-of-flight mass spectrometry (ATOFMS) is able to monitor the size and chemical composition of individual particles in real time. In this doctoral research, ATOFMS analysis was extended to identify new mass spectral markers and improve the potential for quantitative measurements. Development of novel instrumentation was also undertaken. Ion markers indicative of organosulfate compounds were identified in ATOFMS mass spectra collected in Atlanta, GA. In this study, the mixing state and temporal behavior of particulate organosulfate compounds were observed for the first time. Organosulfates were overwhelmingly detected in carbonaceous submicron particles and the temporal trends indicated that they likely formed by the daytime oxidation of isoprene followed by aqueous reaction with sulfate overnight. These results highlight the roles of mixing state and multi-phase reactivity on the formation of secondary organic aerosols. ATOFMS measurements of thermally-conditioned aerosol residuals obtained during the 2005 Study of Organic Aerosols in Riverside, CA were analyzed to determine the impacts of atmospheric aging on the laser desorption/ionization process. Coatings of secondary species suppressed the ionization efficiency, thereby impacting the mass spectral peak areas; however, a novel analysis method was found to correct these artifacts and produced strong agreement with collocated quantitative instrumentation. This new analysis technique was then applied to investigate the mixing-state dependence of aerosol volatility observed in Riverside. It was observed that particulate nitrate evaporated at different temperatures from different particle types (e.g., organic vs. biomass burning), which may influence the regional transport of nitrate species. ATOFMS provides important insights into size-resolved particle sources; however it heavily fragments most organic species, resulting in loss of the molecular information. Therefore, a novel chemical ionization mass spectrometer was developed to better characterize the molecular organic aerosol constituents. In particular, an ion funnel was incorporated into a home-built proton-transfer-reaction mass spectrometer. Initial characterization studies and ion simulations indicated that the ion funnel can provide high-efficiency ion transfer from the ionization region to the mass spectrometer. These results demonstrate the potential for this instrument to ultimately achieve highly sensitive analyses of organic aerosols.

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 Investigations Into the Impact of Transported Particles on Air Pollution and Climate Using Aerosol Time of flight Mass Spectrometry written by Andrew Phillip Ault and published by . This book was released on 2010 with total page 558 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atmospheric aerosols have a significant impact on human health and climate, yet the full scope of these influences are only beginning to be discovered and characterized. To understand these impacts, detailed in-situ measurements of the physical, chemical, and optical properties of aerosols are necessary. Aerosol time-of-flight mass spectrometry (ATOFMS) provides the ability to measure chemical, physical, and optical properties of single particles in real-time. This dissertation uses ATOFMS to explore both the properties and evolution of particles as they are transported over local to global distances. The results of numerous field studies are utilized to explore the changes to these particles as they travel through the atmosphere from their source to eventual deposition. Local to regional scale transport of particles was observed from a number of perspectives in this dissertation. Particles regionally transported from the Ports of Los Angeles and Long Beach to San Diego were identified chemically as ship and truck emissions and shown to overwhelm local sources during peak transport conditions. Ship emissions were studied in detail at the Port of Los Angeles by characterizing individual ship plumes at a site adjacent to the main channel. Mobile laboratory measurements demonstrated the variation in particle concentrations and composition on a local-to-regional level. On the intercontinental-to-global scale, Asian dust was observed in precipitation samples collected in the Sierra Nevada Mountains during orographic precipitation. The incorporation of the long range-transported dust might enhance precipitation, which may alter California's precipitation patterns and water supply. The outflow of particles from Asia to North America were measured on a remote island off Korea, and the sources and aging of particles in Chinese urban, Chinese dust, and Korean air masses were compared to marine air masses. Lastly, ATOFMS studies from sites across North America, Asia, Europe, and Africa were compared to determine similarities and differences in size-resolved chemical mixing state of particles across numerous types of sampling sites, with the objective being to provide information for global climate models to more accurately represent particles. Taken together these results provide an increased understanding of particle chemistry and transport on the scale of meters-to-continents.

Download or read book Analysis Concepts Of Aerosols by On Line Aerosol Mass Spectrometry written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: It is known that aerosols have an impact on climate, air quality and health. To better characterize these effects, the knowledge of the aerosol particle properties, such as size and chemical composition, at the individual level is needed. Toward this purpose, a Single Particle Aerosol Laser Mass Spectrometer (SPALMS) has been designed and developed to characterize in details the organic fraction of particles. The instrument samples the aerosol with a nozzle system and sizes particles individually by laser velocimetry. The single particle constituents are then volatilized (desorption) and ionized (ionization) by laser. The resulting cations and anions are analyzed with a bipolar time-of-flight mass spectrometer. The resulting mass spectra provide a "fingerprint" of the particle composition. Thus the SPALMS instrument evaluates the mixing state, external versus internal, of the aerosol and allows the investigation of the chemical composition size dependency of the particles. The desorption and ionization steps are critical to obtain a good qualitative chemical analysis of the particle. Indeed many processes take place during these steps which fragment and alter the initial molecules in the particle. The simultaneous desorption and ionization with a single laser (337 nm) combined with a bipolar mass spectrometer is well suited for the analysis of mineral particles. On the other hand, organics in particles are better analyzed by operating first the constituents desorption with an infra-red laser (10.6 micrometers) and then the ionization shortly after with an ultra-violet laser (248 nm). Indeed molecules are softly ionized via a SPI or REMPI process. In this manner the resulting mass spectra are more representative of the particle composition since organics are less fragmented. As the SPALMS instrument involves many different measurement steps based of very different principles, it is equipped with many data acquisition devices (up to 12 channels) to record the correspo.

Download or read book Development and Use of Particle Into Liquid Sampling Time of flight Mass Spectrometry PILS ToF for Characterization of Aerosol Particles written by Christopher Holmes Clark and published by . This book was released on 2012 with total page 249 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dissertation introduces and makes use of the Particle-into-Liquid-Sampler coupled to a Time-of-Flight mass spectrometer (PILS-ToF), a new instrumental method used here to provide new chemical characterization information on secondary organic aerosol (SOA). The PILS-ToF instrument improves upon drawbacks found in current state-of-the-art mass spectral chemical characterization methods to include lack of time resolution and ion fragmentation by electron impact ionization in the Aerodyne Aerosol Mass Spectrometer (AMS). The functionality of the PILS-ToF for collection and response to SOA particle formation is validated against a scanning mobility particle sizer (SMPS), a widely accepted and standardized physical chemical characterization instrument, for a well characterized SOA formation experiment, dark ozonolysis of [alpja]-pinene. The PILS-ToF is also used to lend insight into oligomer growth during the NO photo-oxidation of isoprene. It is of atmospheric importance to study SOA formation from isoprene as it is globally the most abundant non-methane hydrocarbon in the ambient. SOA from isoprene is further studied using the PILS-ToF as part of the suite instrumentation at the University of California, Riverside, College of Engineering, Center for Environmental Research and Technology (CE-CERT) atmospheric chamber providing a complete chemical and physical characterization of SOA formed by isoprene with various oxidants under a myriad of oxidant concentration conditions. In addition, the PILS-ToF is used, again in tandem with other chemical and physical characterization methods at CE-CERT, to probe temperature effects on SOA formation from isoprene under many different oxidizing conditions. Finally, the PILS-ToF is used to provide new mechanistic information on SOA formation from trimethylamine and tributylamine, two tertiary amines emitted from anthropogenic and animal husbandry processes. For these two teriary amines the PILS-ToF provides evidence of oligomerization giving a potential explanation to the high SOA yields from these parent compounds.

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 Three dimensional Measurements of Aerosol Mixing State During CalNex Using Aircraft Aerosol Time of flight Mass Spectrometry written by Kaitlyn J. Suski and published by . This book was released on 2013 with total page 105 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 Three dimensional Measurements of Aerosol Mixing State During CalNex Using Aircraft Aerosol Time of flight Mass Spectrometry written by Kimberly A. Prather and published by . This book was released on 2013 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Determination of the Spatial and Temporal Variability of Size resolved P 25 Composition and Mixing State in Multiple Regions in California written by and published by . This book was released on 2009 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt: