Article
Engineering, Environmental
Clara M. Nussbaumer, Ronald C. Cohen
Summary: Air quality policy in the Los Angeles megacity has significantly reduced aerosol concentrations and high aerosol event frequency over the last 20 years. Emission control has been effective in decreasing temperature-independent sources, making aerosol response to temperature a dominant feature of high aerosol events. Organics in aerosols increase with temperature, with certain molecules explaining the observed temperature dependence of PM 2.5.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2021)
Article
Engineering, Civil
Filippos Filippitzis, Monica D. Kohler, Thomas H. Heaton, Robert W. Graves, Robert W. Clayton, Richard G. Guy, Julian J. Bunn, K. Mani Chandy
Summary: The study reveals significant ground-motion amplification in urban Los Angeles during the two largest events of the 2019 Ridgecrest earthquake sequence. Coherent spectral acceleration patterns are visible in the Los Angeles Basin for longer periods, while coherence is less for shorter periods but still observable at smaller length scales due to high spatial density of measurements. Correlations of computed response spectral accelerations with basement depth and Vs30 are stronger for longer periods. The performance of state-of-the-art methods for estimating ground motions is tested, with both methods showing reasonable match with observations but unable to reproduce details of observed amplification patterns.
EARTHQUAKE SPECTRA
(2021)
Article
Engineering, Environmental
Arbor J. L. Quist, Yoshira Ornelas Van Horne, Shohreh F. Farzan, Jill E. Johnston
Summary: Urban environmental justice communities are potentially exposed to multiple toxic metals, and their sources are identified using non-negative matrix factorization (NMF) in this study. The findings suggest that these metals may originate from industrial activities, oil drilling, and dietary sources, which have different clustering patterns in the population near an urban oil drilling site.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2022)
Review
Pharmacology & Pharmacy
Narimane Lammari, Ouahida Louaer, Abdeslam Hassen Meniai, Hatem Fessi, Abdelhamid Elaissari
Summary: In the past decade, there has been a growing global demand for essential and vegetable oils in various industries due to their natural safety and multifunctional properties. However, challenges in developing new therapies or functional agents based on plant oils have led to increased research interest in encapsulation technologies.
INTERNATIONAL JOURNAL OF PHARMACEUTICS
(2021)
Article
Environmental Sciences
Shengjie Liu, An-Min Wu, Hung Chak Ho
Summary: Urbanization alters the Earth's emissivity and leads to intraurban differences in temperature variations, including diurnal temperature range (DTR). This study evaluated associations between climate-sensitive urban design and long-term DTR exposure in Los Angeles. The results showed that compact low-rise areas had high DTR, high-rise areas had moderate DTR, and natural areas had the lowest DTR. Vulnerable populations were more exposed to high DTR, and neighborhoods with higher DTR exhibited higher mortality risk.
Article
Environmental Sciences
Min Shao, Wenjie Wang, Bin Yuan, David D. Parrish, Xin Li, Keding Lu, Luolin Wu, Xuemei Wang, Ziwei Mo, Suxia Yang, Yuwen Peng, Ye Kuang, Weihua Chen, Min Hu, Limin Zeng, Hang Su, Yafang Cheng, Junyu Zheng, Yuanhang Zhang
Summary: In recent years, China has seen a decrease in ambient fine particle levels but an increase in ground-level ozone concentrations in cities like Beijing. The impact of PM2.5 reduction on ozone formation depends on both PM2.5 levels and the optical properties of particles.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Environmental Sciences
Farzan Oroumiyeh, Michael Jerrett, Irish Del Rosario, Jonah Lipsitt, Jonathan Liu, Suzanne E. Paulson, Beate Ritz, James J. Schauer, Martin M. Shafer, Jiaqi Shen, Scott Weichenthal, Sudipto Banerjee, Yifang Zhu
Summary: The study revealed that elements in particulate matter are influenced by traffic emissions, with significant spatial variations across different locations indicating diverse emission sources. Traffic emissions were found to be the main contributor to PM2.5, while mineral dust was the dominant source of PM2.5-10.
ENVIRONMENTAL POLLUTION
(2022)
Article
Geochemistry & Geophysics
Grace A. Parker, Annemarie S. Baltay
Summary: The study develops a spatially continuous site response model for seismic stations in the Los Angeles area using recorded ground motions from 414 earthquakes. The model improves the accuracy of ground motions and warning times for earthquake early warning systems, and can be implemented in regional seismic hazard analyses.
BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA
(2022)
Article
Environmental Sciences
Linan Liu, Wendy Zhou, Marte Gutierrez
Summary: This study applies the PSInSAR technique to measure ground subsidence related to a twin-tunnel excavation in downtown Los Angeles. The technique is suitable for urban areas and the vertical deformation rate is derived from SAR images. The results show local and uneven settlements up to approximately 12 mm/year along the tunnel alignment, with no severe damages to aboveground structures reported. The dominant contributing factor to the ground subsidence is the thickness of artificial fill and alluvium soils above the tunnel springline. Rating: 8 out of 10.
Article
Geochemistry & Geophysics
Rongrong Lin, Grace A. Parker, Jeffrey J. McGuire, Annemarie S. Baltay
Summary: In this study, we investigated whether the Parker and Baltay (2022) site response models can enhance ground-motion forecasts in the ShakeAlert earthquake early warning system for the Los Angeles basin region. By implementing the site response models in ShakeAlert, we found that the system can cover larger areas and provide longer warning times in the LA region. Furthermore, the accuracy of ground-motion predictions, specifically the modified Mercalli intensity (MMI) forecasts, improved when the nonergodic site response model was applied.
BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA
(2023)
Article
Geosciences, Multidisciplinary
Stephen R. Kraemer
Summary: Physics-based groundwater flow modeling is a useful tool for designing and optimizing pump-and-treat systems for groundwater cleanup. Different methods for assigning boundary conditions to the numerical models were demonstrated in a case study in Torrance, California. The study showed the importance of accurately choosing the appropriate boundary conditions to obtain meaningful results.
Article
Environmental Sciences
Yan Chen, Chenjuan Deng, Ting Lei, Junling Li, Chaofan Lian, Yiran Li, Jun Zheng, Jun Zhao, Dongbin Wang, Zhijun Wu, Lin Wang, Lei Li, Hong Li, Jian Gao, Jingkun Jiang, Maofa Ge, Weigang Wang
Summary: By using a custom-made Nanoparticle Chemical Ionization Mass Spectrometer (NPCIMS), we conducted comprehensive field measurements of the size-resolved chemical composition of atmospheric nanoparticles in the size range from 10 to 100 nm. The quantification results showed that CHO organics accounted for around 80% of the newly formed particles in the growth process with diameters from 10 to 25 nm. In contrast to previous observations in urban Mexico, the growth of newly formed particles in urban Beijing was dominated by ammonium, sulfate, and organic components in the size-resolved modes (10-25 nm) during springtime.
ATMOSPHERIC ENVIRONMENT
(2023)
Article
Chemistry, Physical
Samuel D. Winter, Hannah B. L. Jones, Dora M. Rasadean, Rory M. Crean, Michael J. Danson, G. Dan Panto, Gergely Katona, Erica Prentice, Vickery L. Arcus, Marc W. van der Kamp, Christopher R. Pudney
Summary: This study investigates how individual substrate interactions affect the temperature dependence of enzyme activity and the network of motions throughout the protein, revealing how subtle changes in substrate binding can affect global changes in motion and flexibility extending throughout the protein.
Article
Engineering, Chemical
James N. Smith, Danielle C. Draper, Sabrina Chee, Michelia Dam, Hayley Glicker, Deanna Myers, Adam E. Thomas, Michael J. Lawler, Nanna Myllys
Summary: Aerosol nanoclusters (AN), molecular aggregates suspended in gas with dimensions between 2 and 10 nm, play a crucial role in connecting molecules and gas phase with particles and condensed phase. Understanding the physical and chemical properties of size-resolved AN is essential for studying the formation and evolution of particles in various environments. Current measurement and modeling techniques, although still rudimentary, show potential for closing the gap between gas-phase clusters and nanoparticles by improving instruments and theoretical methods.
JOURNAL OF AEROSOL SCIENCE
(2021)
Article
Engineering, Aerospace
Jongil Jung, Suyeon Oh, Yu Yi
Summary: Solar energetic particle (SEP) events are caused by solar flares and coronal mass ejections. Ground level enhancement (GLE) is an increase in the count rate of a ground neutron monitor. This study compared the chemical composition ratio during SEP events with and without GLE to understand the origin of these events on the solar surface. The study found that helium shows a significantly higher intensity during SEP events, suggesting nuclear fusion near the solar surface.
ADVANCES IN SPACE RESEARCH
(2023)
Article
Public, Environmental & Occupational Health
R. B. Newsom, A. Amara, A. Hicks, M. Quint, C. Pattison, B. R. Bzdek, J. Burridge, C. Krawczyk, J. Dinsmore, J. Conway
Summary: Accurate mapping of droplet spread in clinical environments is possible using fluorescein staining and image analysis. Laminar air flow mainly affected smaller droplets, with limited impact on larger droplets.
JOURNAL OF HOSPITAL INFECTION
(2021)
Editorial Material
Critical Care Medicine
Fergus Hamilton, David Arnold, Bryan Bzdek, James Dodd, Jonathan Reid, Nick Maskell
LANCET RESPIRATORY MEDICINE
(2021)
Letter
Anesthesiology
A. J. Shrimpton, J. M. Brown, T. M. Cook, A. E. Pickering
Article
Gastroenterology & Hepatology
Florence K. A. Gregson, Andrew J. Shrimpton, Fergus Hamilton, Tim M. Cook, Jonathan P. Reid, Anthony E. Pickering, Dimitri J. Pournaras, Bryan R. Bzdek, Jules Brown
Summary: Coughing during OGD is identified as the main source event for increased aerosol levels, highlighting the importance of appropriate precautions. Additionally, insertion and removal of the endoscope typically do not generate aerosols unless triggered by coughing.
Article
Anesthesiology
A. J. Shrimpton, J. M. Brown, F. K. A. Gregson, T. M. Cook, D. A. Scott, F. McGain, R. S. Humphries, R. S. Dhillon, J. P. Reid, F. Hamilton, B. R. Bzdek, A. E. Pickering
Summary: The study shows that manual facemask ventilation, even with an intentional leak, does not generate high levels of bioaerosol. Therefore, the authors argue that facemask ventilation should not be considered an aerosol-generating procedure.
Article
Respiratory System
Fergus W. Hamilton, Florence K. A. Gregson, David T. Arnold, Sadiyah Sheikh, Kirsty Ward, Jules Brown, Ed Moran, Carrie White, Anna J. Morley, Bryan R. Bzdek, Jonathan P. Reid, Nicholas A. Maskell, James William Dodd
Summary: This study aimed to compare aerosol emission from HFNO and CPAP with breathing, speaking, and coughing. It found that in healthy volunteers, CPAP produced less aerosol than breathing, speaking, and coughing, while HFNO emissions mainly came from the machine and were unlikely to carry viral particles. Patients with COVID-19 coughed out more aerosol than volunteers.
Editorial Material
Respiratory System
Sadiyah Sheikh, Fergus W. Hamilton, George W. Nava, Florence K. A. Gregson, David T. Arnold, Colleen Riley, Jules Brown, Jonathan P. Reid, Bryan R. Bzdek, Nicholas A. Maskell, James William Dodd
Summary: Pulmonary function tests are essential for diagnosing respiratory diseases, but the production of potentially infectious aerosols during testing has been a concern. This study found that coughing generated the highest aerosol emission, while the use of viral filters and masks significantly reduced aerosol emission. Mitigation strategies such as these could help reduce the risk of transmission to staff during lung function testing.
Article
Multidisciplinary Sciences
Tom Dudding, Sadiyah Sheikh, Florence Gregson, Jennifer Haworth, Simon Haworth, Barry G. Main, Andrew J. Shrimpton, Fergus W. Hamilton, Aerator Group, Anthony J. Ireland, Nick A. Maskell, Jonathan P. Reid, Bryan R. Bzdek, Mark Gormley
Summary: The study quantified the aerosol generated during various dental procedures and identified the potential sources of aerosol generation. It found that high and slow speed drilling procedures may pose a greater risk of salivary contamination. This study provides evidence for better evaluation of risk and implementation of appropriate mitigation strategies.
Article
Engineering, Chemical
George H. Downing, Yannis Hardalupas, Justice Archer, Henry E. Symons, Ulas Baran Baloglu, Daniel Schien, Bryan R. Bzdek, Jonathan P. Reid
Summary: This study compares computational simulations and measurements of aerosol dispersion in a ventilated classroom, finding that a newly developed aerosol transport model can accurately simulate dispersion and predict measured concentrations. The experiments highlight how the maximum aerosol concentration within a room can be many times higher than the average concentration, increasing the risk of infection.
AEROSOL SCIENCE AND TECHNOLOGY
(2022)
Article
Engineering, Chemical
Joshua Harrison, Brian Saccente-Kennedy, Christopher M. Orton, Lauren P. McCarthy, Justice Archer, Henry E. Symons, Alicja Szczepanska, Natalie A. Watson, William J. Browne, Benjamin Moseley, Keir E. J. Philip, James H. Hull, James D. Calder, Declan Costello, Pallav L. Shah, Ruth Epstein, Jonathan P. Reid, Bryan R. Bzdek
Summary: This study quantifies the generation of respiratory droplets (>20 μm) by a cohort of 76 adults and children using a water-sensitive paper droplet deposition approach. The study finds that oral articulation drives the production of droplets larger than 20 μm, while breathing generates virtually no droplets. The study also compares aerosol and droplet emissions for the same participants and reports the full size distribution of respiratory aerosols (0.5-1000 μm).
AEROSOL SCIENCE AND TECHNOLOGY
(2023)
Article
Engineering, Chemical
Alicja Szczepanska, Joshua Harrison, Brian Saccente-Kennedy, Justice Archer, Natalie A. Watson, Christopher M. Orton, William J. Browne, Ruth Epstein, James D. Calder, Pallav L. Shah, Declan Costello, Bryan R. Bzdek, Jonathan P. Reid
Summary: Surgical face masks are effective in reducing the emission of respiratory particles and droplets, with varying filtration efficiency depending on the task. For particles with a diameter of 0.5-2 μm, filtration efficiency is high, while for particles larger than 4 μm, filtration efficiency is close to 100%. These results are important for preventing disease transmission through inhalation.
AEROSOL SCIENCE AND TECHNOLOGY
(2023)
Article
Anesthesiology
A. J. Shrimpton, V. Brown, J. Vassallo, J. P. Nolan, J. Soar, F. Hamilton, T. M. Cook, B. R. Bzdek, J. P. Reid, C. H. Makepeace, J. Deutsch, R. Ascione, J. M. Brown, J. R. Benger, A. E. Pickering
Summary: Cardiopulmonary resuscitation generates high concentrations of respiratory aerosol, suggesting the need for airborne transmission precautions in high-risk pathogen settings.
Article
Cell & Tissue Engineering
V. Hamilton, S. Sheikh, A. Szczepanska, N. Maskell, F. Hamilton, J. P. Reid, B. R. Bzdek, J. R. D. Murray
Summary: This study quantifies the aerosol exposure in orthopaedic surgeries and suggests additional precautions for diathermy and bone sawing to reduce exposure.
BONE & JOINT RESEARCH
(2023)
Article
Environmental Sciences
Alison Bain, Man Nin Chan, Bryan R. R. Bzdek
Summary: Organosulfates make up to 30% of the organic fraction of aerosol. Understanding their physical properties is crucial for predicting their impact on global climate, yet current knowledge is limited. This study measures the physical properties of aqueous solutions containing sodium methyl or ethyl sulfate and compares them with literature data for organosulfates, salts, and organics. The results show that organosulfates have intermediate physical properties between salts and short alkyl chain organics, except for water activity. This work emphasizes the importance of measuring and developing models for the physical properties of abundant atmospheric organosulfates to better understand aerosol's climate impact.
ENVIRONMENTAL SCIENCE-ATMOSPHERES
(2023)
Article
Biology
Justice Archer, Lauren P. McCarthy, Henry E. Symons, Natalie A. Watson, Christopher M. Orton, William J. Browne, Joshua Harrison, Benjamin Moseley, Keir E. J. Philip, James D. Calder, Pallav L. Shah, Bryan R. Bzdek, Declan Costello, Jonathan P. Reid
Summary: This study provides a robust assessment of the absolute particle number and mass exhalation rates from measurements of minute ventilation. The results indicate that children and adults generate similar amounts of aerosol when performing the same activity, and aerosol exhalation rate increases with increasing sound volume.