Publications by authors named "Taylor Shingler"

11 Publications

  • Page 1 of 1

Coupling an online ion conductivity measurement with the particle-into-liquid sampler: Evaluation and modeling using laboratory and field aerosol data.

Aerosol Sci Technol 2020 12;54(12):1542-1555. Epub 2020 Aug 12.

Science Systems and Applications, Inc., Hampton, Virginia, USA.

A particle-into-liquid sampler (PILS) was coupled to a flow-through conductivity cell to provide a continuous, nondestructive, online measurement in support of offline ion chromatography analysis. The conductivity measurement provides a rapid assessment of the total ion concentration augmenting slower batch-sample data from offline analysis and is developed primarily to assist airborne measurements, where fast time-response is essential. A conductivity model was developed for measured ions and excellent closure was derived for laboratory-generated aerosols (97% conductivity explained, R > 0.99). The PILS-conductivity measurement was extensively tested throughout the NASA Cloud, Aerosol and Monsoon Processes: Philippines Experiment (CAMPEx) during nineteen research flights. A diverse range of ambient aerosol was sampled from biomass burning, fresh and aged urban pollution, and marine sources. Ambient aerosol did not exhibit the same degree of closure as the laboratory aerosol, with measured ions only accountable for 43% of the conductivity. The remaining fraction of the conductivity was examined in combination with ion charge balance and found to provide additional supporting information for diagnosing and modeling particle acidity. An urban plume case study was used to demonstrate the utility of the measurement for supplementing compositional data and augmenting the temporal capability of the PILS.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/02786826.2020.1795499DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7668158PMC
August 2020

Atmospheric Research Over the Western North Atlantic Ocean Region and North American East Coast: A Review of Past Work and Challenges Ahead.

J Geophys Res Atmos 2020 Mar 18;125(6). Epub 2020 Feb 18.

Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL.

Decades of atmospheric research have focused on the Western North Atlantic Ocean (WNAO) region because of its unique location that offers accessibility for airborne and ship measurements, gradients in important atmospheric parameters, and a range of meteorological regimes leading to diverse conditions that are poorly understood. This work reviews these scientific investigations for the WNAO region, including the East Coast of North America and the island of Bermuda. Over 50 field campaigns and long-term monitoring programs, in addition to 715 peer-reviewed publications between 1946 and 2019 have provided a firm foundation of knowledge for these areas. Of particular importance in this region has been extensive work at the island of Bermuda that is host to important time series records of oceanic and atmospheric variables. Our review categorizes WNAO atmospheric research into eight major categories, with some studies fitting into multiple categories (relative %): Aerosols (25%), Gases (24%), Development/Validation of Techniques, Models, and Retrievals (18%), Meteorology and Transport (9%), Air-Sea Interactions (8%), Clouds/Storms (8%), Atmospheric Deposition (7%), and Aerosol-Cloud Interactions (2%). Recommendations for future research are provided in the categories highlighted above.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1029/2019jd031626DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7375207PMC
March 2020

Development and characterization of a high-efficiency, aircraft-based axial cyclone cloud water collector.

Atmos Meas Tech 2018 Aug 5;11(9):5025-5048. Epub 2018 Sep 5.

NASA Langley Research Center, Hampton, VA 23666, USA.

A new aircraft-mounted probe for collecting samples of cloud water has been designed, fabricated, and extensively tested. Following previous designs, the probe uses inertial separation to remove cloud droplets from the airstream, which are subsequently collected and stored for offline analysis. We report details of the design, operation, and modelled and measured probe performance. Computational fluid dynamics (CFD) was used to understand the flow patterns around the complex interior geometrical features that were optimized to ensure efficient droplet capture. CFD simulations coupled with particle tracking and multiphase surface transport modelling provide detailed estimates of the probe performance across the entire range of flight operating conditions and sampling scenarios. Physical operation of the probe was tested on a Lockheed C-130 Hercules (fuselage mounted) and de Havilland Twin Otter (wing pylon mounted) during three airborne field campaigns. During C-130 flights on the final field campaign, the probe reflected the most developed version of the design and a median cloud water collection rate of 4.5 mL min was achieved. This allowed samples to be collected over 1-2 min under optimal cloud conditions. Flights on the Twin Otter featured an inter-comparison of the new probe with a slotted-rod collector, which has an extensive airborne campaign legacy. Comparison of trace species concentrations showed good agreement between collection techniques, with absolute concentrations of most major ions agreeing within 30 %, over a range of several orders of magnitude.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.5194/amt-11-5025-2018DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8051007PMC
August 2018

A multi-year data set on aerosol-cloud-precipitation-meteorology interactions for marine stratocumulus clouds.

Sci Data 2018 02 27;5:180026. Epub 2018 Feb 27.

Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, USA.

Airborne measurements of meteorological, aerosol, and stratocumulus cloud properties have been harmonized from six field campaigns during July-August months between 2005 and 2016 off the California coast. A consistent set of core instruments was deployed on the Center for Interdisciplinary Remotely-Piloted Aircraft Studies Twin Otter for 113 flight days, amounting to 514 flight hours. A unique aspect of the compiled data set is detailed measurements of aerosol microphysical properties (size distribution, composition, bioaerosol detection, hygroscopicity, optical), cloud water composition, and different sampling inlets to distinguish between clear air aerosol, interstitial in-cloud aerosol, and droplet residual particles in cloud. Measurements and data analysis follow documented methods for quality assurance. The data set is suitable for studies associated with aerosol-cloud-precipitation-meteorology-radiation interactions, especially owing to sharp aerosol perturbations from ship traffic and biomass burning. The data set can be used for model initialization and synergistic application with meteorological models and remote sensing data to improve understanding of the very interactions that comprise the largest uncertainty in the effect of anthropogenic emissions on radiative forcing.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/sdata.2018.26DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5827690PMC
February 2018

Take-off engine particle emission indices for in-service aircraft at Los Angeles International Airport.

Sci Data 2017 12 19;4:170198. Epub 2017 Dec 19.

NASA Langley Research Center, Hampton, VA 23681, USA.

We present ground-based, advected aircraft engine emissions from flights taking off at Los Angeles International Airport. 275 discrete engine take-off plumes were observed on 18 and 25 May 2014 at a distance of 400 m downwind of the runway. CO measurements are used to convert the aerosol data into plume-average emissions indices that are suitable for modelling aircraft emissions. Total and non-volatile particle number EIs are of order 10-10 kg and 10-10 kg, respectively. Black-carbon-equivalent particle mass EIs vary between 175-941 mg kg (except for the GE GEnx engines at 46 mg kg). Aircraft tail numbers recorded for each take-off event are used to incorporate aircraft- and engine-specific parameters into the data set. Data acquisition and processing follow standard methods for quality assurance. A unique aspect of the data set is the mapping of aerosol concentration time series to integrated plume EIs, aircraft and engine specifications, and manufacturer-reported engine emissions certifications. The integrated data enable future studies seeking to understand and model aircraft emissions and their impact on air quality.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/sdata.2017.198DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5744856PMC
December 2017

Analysis of remotely sensed and surface data of aerosols and meteorology for the Mexico Megalopolis Area between 2003 and 2015.

J Geophys Res Atmos 2017 Aug 17;122(16):8705-8723. Epub 2017 Aug 17.

Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona, USA.

This paper presents an aerosol characterization study from 2003 to 2015 for the Mexico City Metropolitan Area using remotely sensed aerosol data, ground-based measurements, air mass trajectory modeling, aerosol chemical composition modeling, and reanalysis data for the broader Megalopolis of Central Mexico region. The most extensive biomass burning emissions occur between March and May concurrent with the highest aerosol optical depth, ultraviolet aerosol index, and surface particulate matter (PM) mass concentration values. A notable enhancement in coarse PM levels is observed during vehicular rush hour periods on weekdays versus weekends owing to nonengine-related emissions such as resuspended dust. Among wet deposition species measured, PM, PM, and PM (PM-PM) were best correlated with NH, SO, and Ca, suggesting that the latter three constituents are important components of the aerosol seeding raindrops that eventually deposit to the surface in the study region. Reductions in surface PM mass concentrations were observed in 2014-2015 owing to reduced regional biomass burning as compared to 2003-2013.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/2017JD026739DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5611832PMC
August 2017

Ambient observations of sub-1.0 hygroscopic growth factor and (RH) values: Case studies from surface and airborne measurements.

J Geophys Res Atmos 2016 Nov 7;121(22):661-677. Epub 2016 Nov 7.

Department of Chemical and Environmental Engineering, University of Arizona, Tucson, AZ, USA.

This study reports on the first set of ambient observations of sub-1.0 hygroscopicity values (i.e., growth factor, ratio of humidified-to-dry diameter, and (RH), ratio of humidified-to-dry scattering coefficients, less than 1) with consistency across different instruments, regions, and platforms. We utilized data from (i) a shipboard humidified tandem differential mobility analyzer (HTDMA) during Eastern Pacific Emitted Aerosol Cloud Experiment (E-PEACE) in 2011, (ii) multiple instruments on the DC-8 aircraft during Studies of Emissions, Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEACRS) in 2013, as well as (iii) the Differential Aerosol Sizing and Hygroscopicity Spectrometer Probe (DASH-SP) during measurement intensives during Summer 2014 and Winter 2015 in Tucson, Arizona. Sub-1.0 s were observed across the range of relative humidity (RH) investigated (75-95%), and did not show a RH-dependent trend in value below 1.0 or frequency of occurrence. A commonality between suppressed hygroscopicity in these experiments, including sub-1.0 , was the presence of smoke. Evidence of externally mixed aerosol, and thus multiple s, was observed during smoke periods resulting in at least one mode with < 1. Time periods during which the DASH-SP detected externally mixed aerosol coincide with sub-1.0 (RH) observations. Mechanisms responsible for sub-1.0 hygroscopicity are discussed and include refractive index (RI) modifications due to aqueous processing, particle restructuring, and volatilization effects. To further investigate ambient observations of sub-1.0 s, (RH), and particle restructuring, modifying hygroscopicity instruments with pre-humidification modules is recommended.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/2016JD025471DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7821680PMC
November 2016

Hygroscopic Properties and Respiratory System Deposition Behavior of Particulate Matter Emitted By Mining and Smelting Operations.

Environ Sci Technol 2016 11 13;50(21):11706-11713. Epub 2016 Oct 13.

Mel and Enid Zuckerman College of Public Health, University of Arizona , Tucson, Arizona 85724, United States.

This study examines size-resolved physicochemical data for particles sampled near mining and smelting operations and a background urban site in Arizona with a focus on how hygroscopic growth impacts particle deposition behavior. Particles with aerodynamic diameters between 0.056-18 μm were collected at three sites: (i) an active smelter operation in Hayden, AZ, (ii) a legacy mining site with extensive mine tailings in Iron King, AZ, and (iii) an urban site, inner-city Tucson, AZ. Mass size distributions of As and Pb exhibit bimodal profiles with a dominant peak between 0.32 and 0.56 μm and a smaller mode in the coarse range (>3 μm). The hygroscopicity profile did not exhibit the same peaks owing to dependence on other chemical constituents. Submicrometer particles were generally more hygroscopic than supermicrometer ones at all three sites with finite water-uptake ability at all sites and particle sizes examined. Model calculations at a relative humidity of 99.5% reveal significant respiratory system particle deposition enhancements at sizes with the largest concentrations of toxic contaminants. Between dry diameters of 0.32 and 0.56 μm, for instance, ICRP and MPPD models predict deposition fraction enhancements of 171%-261% and 33%-63%, respectively, at the three sites.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5089925PMC
http://dx.doi.org/10.1021/acs.est.6b03621DOI Listing
November 2016

Surface and Airborne Measurements of Organosulfur and Methanesulfonate Over the Western United States and Coastal Areas.

J Geophys Res Atmos 2015 Aug;120(16):8535-8548

Center for Interdisciplinary Remotely Piloted Aircraft Studies, Naval Postgraduate School, Monterey, CA, United States.

This study reports on ambient measurements of organosulfur (OS) and methanesulfonate (MSA) over the western United States and coastal areas. Particulate OS levels are highest in summertime, and generally increase as a function of sulfate (a precursor) and sodium (a marine tracer) with peak levels at coastal sites. The ratio of OS to total sulfur (TS) is also highest at coastal sites, with increasing values as a function of Normalized Difference Vegetation Index (NDVI) and the ratio of organic carbon to elemental carbon. Correlative analysis points to significant relationships between OS and biogenic emissions from marine and continental sources, factors that coincide with secondary production, and vanadium due to a suspected catalytic role. A major OS species, methanesulfonate (MSA), was examined with intensive field measurements and the resulting data support the case for vanadium's catalytic influence. Mass size distributions reveal a dominant MSA peak between aerodynamic diameters of 0.32-0.56 μm at a desert and coastal site with nearly all MSA mass (≥ 84%) in sub-micrometer sizes; MSA:non-sea salt sulfate ratios vary widely as a function of particle size and proximity to the ocean. Airborne data indicate that relative to the marine boundary layer, particulate MSA levels are enhanced in urban and agricultural areas, and also the free troposphere when impacted by biomass burning. Some combination of fires and marine-derived emissions leads to higher MSA levels than either source alone. Finally, MSA differences in cloud water and out-of-cloud aerosol are discussed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/2015JD023822DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4581448PMC
August 2015

A Multi-Year Aerosol Characterization for the Greater Tehran Area Using Satellite, Surface, and Modeling Data.

Atmosphere (Basel) 2014 Apr;5(2):178-197

Department of Civil & Environmental Engineering, University of California, Irvine, Irvine, CA 92697, USA.

This study reports a multi-year (2000-2009) aerosol characterization for metropolitan Tehran and surrounding areas using multiple datasets (Moderate Resolution Imaging Spectroradiometer (MODIS), Multi-angle Imaging Spectroradiometer (MISR), Total Ozone Mapping Spectrometer (TOMS), Goddard Ozone Chemistry Aerosol Radiation and Transport (GOCART), and surface and upper air data from local stations). Monthly trends in aerosol characteristics are examined in the context of the local meteorology, regional and local emission sources, and air mass back-trajectory data. Dust strongly affects the region during the late spring and summer months (May-August) when aerosol optical depth (AOD) is at its peak and precipitation accumulation is at a minimum. In addition, the peak AOD that occurs in July is further enhanced by a substantial number of seasonal wildfires in upwind regions. Conversely, AOD is at a minimum during winter; however, reduced mixing heights and a stagnant lower atmosphere trap local aerosol emissions near the surface and lead to significant reductions in visibility within Tehran. The unique meteorology and topographic setting makes wintertime visibility and surface aerosol concentrations particularly sensitive to local anthropogenic sources and is evident in the noteworthy improvement in visibility observed on weekends. Scavenging of aerosol due to precipitation is evident during the winter when aconsistent increase in surface visibility and concurrent decrease in AOD is observed in the days after rain compared with the days immediately before rain.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/atmos5020178DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4114406PMC
April 2014

Hygroscopic and chemical properties of aerosols collected near a copper smelter: implications for public and environmental health.

Environ Sci Technol 2012 Sep 17;46(17):9473-80. Epub 2012 Aug 17.

Department of Chemical and Environmental Engineering, University of Arizona, Tucson, Arizona 85721, United States.

Particulate matter emissions near active copper smelters and mine tailings in the southwestern United States pose a potential threat to nearby environments owing to toxic species that can be inhaled and deposited in various regions of the body depending on the composition and size of the particles, which are linked by particle hygroscopic properties. This study reports the first simultaneous measurements of size-resolved chemical and hygroscopic properties of particles next to an active copper smelter and mine tailings by the towns of Hayden and Winkelman in southern Arizona. Size-resolved particulate matter samples were examined with inductively coupled plasma mass spectrometry, ion chromatography, and a humidified tandem differential mobility analyzer. Aerosol particles collected at the measurement site are enriched in metals and metalloids (e.g., arsenic, lead, and cadmium) and water-uptake measurements of aqueous extracts of collected samples indicate that the particle diameter range of particles most enriched with these species (0.18-0.55 μm) overlaps with the most hygroscopic mode at a relative humidity of 90% (0.10-0.32 μm). These measurements have implications for public health, microphysical effects of aerosols, and regional impacts owing to the transport and deposition of contaminated aerosol particles.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1021/es302275kDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3435440PMC
September 2012
-->