1
|
Meng Q, Liu J, Shen J, Del Rosario I, Lakey PS, Shiraiwa M, Su J, Weichenthal S, Zhu Y, Oroumiyeh F, Paulson SE, Jerrett M, Ritz B. Fine Particulate Matter Metal Composition, Oxidative Potential, and Adverse Birth Outcomes in Los Angeles. Environ Health Perspect 2023; 131:107012. [PMID: 37878796 PMCID: PMC10599636 DOI: 10.1289/ehp12196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 07/11/2023] [Accepted: 09/18/2023] [Indexed: 10/27/2023]
Abstract
BACKGROUND Although many studies have linked prenatal exposure to PM 2.5 to adverse birth outcomes, little is known about the effects of exposure to specific constituents of PM 2.5 or mechanisms that contribute to these outcomes. OBJECTIVES Our objective was to investigate effects of oxidative potential and PM 2.5 metal components from non-exhaust traffic emissions, such as brake and tire wear, on the risk of preterm birth (PTB) and term low birth weight (TLBW). METHODS For a birth cohort of 285,614 singletons born in Los Angeles County, California, in the period 2017-2019, we estimated speciated PM 2.5 exposures modeled from land use regression with cokriging, including brake and tire wear related metals (barium and zinc), black carbon, and three markers of oxidative potential (OP), including modeled reactive oxygen species based on measured iron and copper (ROS), OH formation (OP OH ), and dithiothreitol (DTT) loss (OP DTT ). Using logistic regression, we estimated odds ratios (OR) and 95% confidence intervals (CI) for PTB and TLBW with speciated PM 2.5 exposures and PM 2.5 mass as continuous variables scaled by their interquartile range (IQR). RESULTS For both metals and oxidative potential metrics, we estimated increased risks for PTB (ORs ranging from 1.01 to 1.03) and TLBW (ORs ranging from 1.02 to 1.05) per IQR exposure increment that were robust to adjustment for PM 2.5 mass. Associations for PM 2.5 mass, black carbon, metal components, and oxidative potential (especially ROS and OP OH ) with adverse birth outcomes were stronger in Hispanic, Black, and mixed-race or Native American women. DISCUSSION Our results indicate that exposure to PM 2.5 metals from brake and tire wear and particle components that contribute to oxidative potential were associated with an increased risk of PTB and TLBW in Los Angeles County, particularly among Hispanic, Black, and mixed-race or Native American women. Thus, reduction of PM 2.5 mass only may not be sufficient to protect the most vulnerable pregnant women and children from adverse effects due to traffic source exposures. https://doi.org/10.1289/EHP12196.
Collapse
Affiliation(s)
- Qi Meng
- Department of Epidemiology, Fielding School of Public Health, University of California, Los Angeles (UCLA), Los Angeles, California, USA
| | - Jonathan Liu
- Department of Environmental Health Sciences, Fielding School of Public Health, UCLA, Los Angeles, California, USA
| | - Jiaqi Shen
- Department of Atmospheric & Oceanic Sciences, UCLA, Los Angeles, California, USA
| | - Irish Del Rosario
- Department of Epidemiology, Fielding School of Public Health, University of California, Los Angeles (UCLA), Los Angeles, California, USA
| | - Pascale S.J. Lakey
- Department of Chemistry, University of California, Irvine, Irvine, California, USA
| | - Manabu Shiraiwa
- Department of Chemistry, University of California, Irvine, Irvine, California, USA
| | - Jason Su
- Environmental Health Sciences, School of Public Health, University of California, Berkeley, Berkeley, California, USA
| | - Scott Weichenthal
- Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, Quebec, Canada
| | - Yifang Zhu
- Department of Environmental Health Sciences, Fielding School of Public Health, UCLA, Los Angeles, California, USA
| | - Farzan Oroumiyeh
- Department of Environmental Health Sciences, Fielding School of Public Health, UCLA, Los Angeles, California, USA
| | - Suzanne E. Paulson
- Department of Atmospheric & Oceanic Sciences, UCLA, Los Angeles, California, USA
| | - Michael Jerrett
- Department of Environmental Health Sciences, Fielding School of Public Health, UCLA, Los Angeles, California, USA
| | - Beate Ritz
- Department of Epidemiology, Fielding School of Public Health, University of California, Los Angeles (UCLA), Los Angeles, California, USA
| |
Collapse
|
2
|
Shen J, Taghvaee S, La C, Oroumiyeh F, Liu J, Jerrett M, Weichenthal S, Del Rosario I, Shafer MM, Ritz B, Zhu Y, Paulson SE. Aerosol Oxidative Potential in the Greater Los Angeles Area: Source Apportionment and Associations with Socioeconomic Position. Environ Sci Technol 2022; 56:17795-17804. [PMID: 36472388 PMCID: PMC9775201 DOI: 10.1021/acs.est.2c02788] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 11/16/2022] [Accepted: 11/17/2022] [Indexed: 06/17/2023]
Abstract
Oxidative potential (OP) has been proposed as a possible integrated metric for particles smaller than 2.5 μm in diameter (PM2.5) to evaluate adverse health outcomes associated with particulate air pollution exposure. Here, we investigate how OP depends on sources and chemical composition and how OP varies by land use type and neighborhood socioeconomic position in the Los Angeles area. We measured OH formation (OPOH), dithiothreitol loss (OPDTT), black carbon, and 52 metals and elements for 54 total PM2.5 samples collected in September 2019 and February 2020. The Positive Matrix Factorization source apportionment model identified four sources contributing to volume-normalized OPOH: vehicular exhaust, brake and tire wear, soil and road dust, and mixed secondary and marine. Exhaust emissions contributed 42% of OPOH, followed by 21% from brake and tire wear. Similar results were observed for the OPDTT source apportionment. Furthermore, by linking measured PM2.5 and OP with census tract level socioeconomic and health outcome data provided by CalEnviroScreen, we found that the most disadvantaged neighborhoods were exposed to both the most toxic particles and the highest particle concentrations. OPOH exhibited the largest inverse social gradients, followed by OPDTT and PM2.5 mass. Finally, OPOH was the metric most strongly correlated with adverse health outcome indicators.
Collapse
Affiliation(s)
- Jiaqi Shen
- Department
of Atmospheric & Oceanic Sciences, University
of California, Los Angeles, California 90095, United States
| | - Sina Taghvaee
- Department
of Atmospheric & Oceanic Sciences, University
of California, Los Angeles, California 90095, United States
| | - Chris La
- Department
of Atmospheric & Oceanic Sciences, University
of California, Los Angeles, California 90095, United States
| | - Farzan Oroumiyeh
- Department
of Environmental Health Sciences, Jonathan and Karin Fielding School
of Public Health, University of California, Los Angeles, California 90095, United States
| | - Jonathan Liu
- Department
of Environmental Health Sciences, Jonathan and Karin Fielding School
of Public Health, University of California, Los Angeles, California 90095, United States
| | - Michael Jerrett
- Department
of Environmental Health Sciences, Jonathan and Karin Fielding School
of Public Health, University of California, Los Angeles, California 90095, United States
| | - Scott Weichenthal
- Department
of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, Quebec H3A 1A2, Canada
| | - Irish Del Rosario
- Department
of Epidemiology, Fielding School of Public Health, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Martin M. Shafer
- Environmental
Chemistry and Technology Program, University
of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Beate Ritz
- Department
of Epidemiology, Fielding School of Public Health, University of California, Los Angeles, Los Angeles, California 90095, United States
| | - Yifang Zhu
- Department
of Environmental Health Sciences, Jonathan and Karin Fielding School
of Public Health, University of California, Los Angeles, California 90095, United States
| | - Suzanne E. Paulson
- Department
of Atmospheric & Oceanic Sciences, University
of California, Los Angeles, California 90095, United States
| |
Collapse
|
3
|
Liu J, Banerjee S, Oroumiyeh F, Shen J, Del Rosario I, Lipsitt J, Paulson S, Ritz B, Su J, Weichenthal S, Lakey P, Shiraiwa M, Zhu Y, Jerrett M. Co-kriging with a low-cost sensor network to estimate spatial variation of brake and tire-wear metals and oxidative stress potential in Southern California. Environ Int 2022; 168:107481. [PMID: 36037546 DOI: 10.1016/j.envint.2022.107481] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 07/22/2022] [Accepted: 08/16/2022] [Indexed: 06/15/2023]
Abstract
Due to regulations and technological advancements reducing tailpipe emissions, an increasing proportion of emissions arise from brake and tire wear particulate matter (PM). PM from these non-tailpipe sources contains heavy metals capable of generating oxidative stress in the lung. Although important, these particles remain understudied because the high cost of actively collecting filter samples. Improvements in electrical engineering, internet connectivity, and an increased public concern over air pollution have led to a proliferation of dense low-cost air sensor networks such as the PurpleAir monitors, which primarily measure unspeciated fine particulate matter (PM2.5). In this study, we model the concentrations of Ba, Zn, black carbon, reactive oxygen species concentration in the epithelial lining fluid, dithiothreitol (DTT) loss, and OH formation. We use a co-kriging approach, incorporating data from the PurpleAir network as a secondary predictor variable and a land-use regression (LUR) as an external drift. For most pollutant species, co-kriging models produced more accurate predictions than an LUR model, which did not incorporate data from the PurpleAir monitors. This finding suggests that low-cost sensors can enhance predictions of pollutants that are costly to measure extensively in the field.
Collapse
Affiliation(s)
- Jonathan Liu
- Department of Environmental Health Sciences, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, 650 Charles E Young Dr S, Los Angeles, CA 90095, United States.
| | - Sudipto Banerjee
- Department of Biostatistics, Jonathan and Karin Fielding School of Public Health, 650 Charles E Young Dr S, Los Angeles, CA 90095, United States.
| | - Farzan Oroumiyeh
- Department of Environmental Health Sciences, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, 650 Charles E Young Dr S, Los Angeles, CA 90095, United States.
| | - Jiaqi Shen
- Department of Atomospheric and Oceanic Sciences, University of Caifornia Los Angeles, 520 Portola Plaza, Los Angeles, CA 90095, United States.
| | - Irish Del Rosario
- Department of Epidemiology, Jonathan and Karin Fielding School of Public Health, 650 Charles E Young Dr S, Los Angeles, CA 90095, United States.
| | - Jonah Lipsitt
- Department of Environmental Health Sciences, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, 650 Charles E Young Dr S, Los Angeles, CA 90095, United States.
| | - Suzanne Paulson
- Department of Atomospheric and Oceanic Sciences, University of Caifornia Los Angeles, 520 Portola Plaza, Los Angeles, CA 90095, United States.
| | - Beate Ritz
- Department of Epidemiology, Jonathan and Karin Fielding School of Public Health, 650 Charles E Young Dr S, Los Angeles, CA 90095, United States.
| | - Jason Su
- Division of Environmental Health Sciences, School of Public Health, University of California at Berkeley, 2121 Berkeley Way, Berkeley, CA, United States.
| | - Scott Weichenthal
- Department of Epidemiology, Biostatistics, and Occupational Health, Faculty of Medicine and Health Sciences, McGill Unviersity, 2001 McGill College, Suite 1200, Montreal, QC H3A 1G1, Canada.
| | - Pascale Lakey
- Deaprtment of Chemistry, University of California, Irvine, Natural Sciences II, 1102, Irvine, CA 92617, United States.
| | - Manabu Shiraiwa
- Deaprtment of Chemistry, University of California, Irvine, Natural Sciences II, 1102, Irvine, CA 92617, United States.
| | - Yifang Zhu
- Department of Environmental Health Sciences, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, 650 Charles E Young Dr S, Los Angeles, CA 90095, United States.
| | - Michael Jerrett
- Department of Environmental Health Sciences, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, 650 Charles E Young Dr S, Los Angeles, CA 90095, United States.
| |
Collapse
|
4
|
Fussell JC, Franklin M, Green DC, Gustafsson M, Harrison RM, Hicks W, Kelly FJ, Kishta F, Miller MR, Mudway IS, Oroumiyeh F, Selley L, Wang M, Zhu Y. A Review of Road Traffic-Derived Non-Exhaust Particles: Emissions, Physicochemical Characteristics, Health Risks, and Mitigation Measures. Environ Sci Technol 2022; 56:6813-6835. [PMID: 35612468 PMCID: PMC9178796 DOI: 10.1021/acs.est.2c01072] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 04/29/2022] [Accepted: 05/10/2022] [Indexed: 05/22/2023]
Abstract
Implementation of regulatory standards has reduced exhaust emissions of particulate matter from road traffic substantially in the developed world. However, nonexhaust particle emissions arising from the wear of brakes, tires, and the road surface, together with the resuspension of road dust, are unregulated and exceed exhaust emissions in many jurisdictions. While knowledge of the sources of nonexhaust particles is fairly good, source-specific measurements of airborne concentrations are few, and studies of the toxicology and epidemiology do not give a clear picture of the health risk posed. This paper reviews the current state of knowledge, with a strong focus on health-related research, highlighting areas where further research is an essential prerequisite for developing focused policy responses to nonexhaust particles.
Collapse
Affiliation(s)
- Julia C. Fussell
- National
Institute for Health Research Health Protection Research Unit in Environmental
Exposures and Health, School of Public Health, Imperial College London, London, W12 0BZ, U.K.
| | - Meredith Franklin
- Department
of Statistical Sciences, University of Toronto, Toronto, Ontario M5G 1Z5, Canada
| | - David C. Green
- National
Institute for Health Research Health Protection Research Unit in Environmental
Exposures and Health, School of Public Health, Imperial College London, London, W12 0BZ, U.K.
| | - Mats Gustafsson
- Swedish
National Road and Transport Research Institute (VTI), SE-581 95, Linköping, Sweden
| | - Roy M. Harrison
- School
of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham, B15 2TT, U.K.
- Department
of Environmental Sciences / Centre of Excellence in Environmental
Studies, King Abdulaziz University, Jeddah, 21589, Saudi Arabia
| | - William Hicks
- National
Institute for Health Research Health Protection Research Unit in Environmental
Exposures and Health, School of Public Health, Imperial College London, London, W12 0BZ, U.K.
| | - Frank J. Kelly
- National
Institute for Health Research Health Protection Research Unit in Environmental
Exposures and Health, School of Public Health, Imperial College London, London, W12 0BZ, U.K.
| | - Franceska Kishta
- Centre
for Cardiovascular Science, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, EH16 4TJ, U.K.
| | - Mark R. Miller
- Centre
for Cardiovascular Science, Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, EH16 4TJ, U.K.
| | - Ian S. Mudway
- National
Institute for Health Research Health Protection Research Unit in Environmental
Exposures and Health, School of Public Health, Imperial College London, London, W12 0BZ, U.K.
| | - Farzan Oroumiyeh
- Department
of Environmental Health Sciences, Jonathan and Karin Fielding School
of Public Health, University of California,
Los Angeles, Los Angeles, California 90095, United States
| | - Liza Selley
- MRC
Toxicology Unit, University of Cambridge, Gleeson Building, Tennis Court Road, Cambridge,CB2 1QR, U.K.
| | - Meng Wang
- University
at Buffalo, School of Public
Health and Health Professions, Buffalo, New York 14214, United States
| | - Yifang Zhu
- Department
of Environmental Health Sciences, Jonathan and Karin Fielding School
of Public Health, University of California,
Los Angeles, Los Angeles, California 90095, United States
| |
Collapse
|
5
|
Oroumiyeh F, Jerrett M, Del Rosario I, Lipsitt J, Liu J, Paulson SE, Ritz B, Schauer JJ, Shafer MM, Shen J, Weichenthal S, Banerjee S, Zhu Y. Elemental composition of fine and coarse particles across the greater Los Angeles area: Spatial variation and contributing sources. Environ Pollut 2022; 292:118356. [PMID: 34653582 DOI: 10.1016/j.envpol.2021.118356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 10/08/2021] [Accepted: 10/09/2021] [Indexed: 05/12/2023]
Abstract
The inorganic components of particulate matter (PM), especially transition metals, have been shown to contribute to PM toxicity. In this study, the spatial distribution of PM elements and their potential sources in the Greater Los Angeles area were studied. The mass concentration and detailed elemental composition of fine (PM2.5) and coarse (PM2.5-10) particles were assessed at 46 locations, including urban traffic, urban community, urban background, and desert locations. Crustal enrichment factors (EFs), roadside enrichments (REs), and bivariate correlation analysis revealed that Ba, Cr, Cu, Mo, Pd, Sb, Zn, and Zr were associated with traffic emissions in both PM2.5 and PM2.5-10, while Fe, Li, Mn, and Ti were affected by traffic emissions mostly in PM2.5. The concentrations of Ba, Cu, Mo, Sb, Zr (brake wear tracers), Pd (tailpipe tracer), and Zn (associated with tire wear) were higher at urban traffic sites than urban background locations by factors of 2.6-4.6. Both PM2.5 and PM2.5-10 elements showed large spatial variations, indicating the presence of diverse emission sources across sampling locations. Principal component analysis extracted four source factors that explained 88% of the variance in the PM2.5 elemental concentrations, and three sources that explained 86% of the variance in the PM2.5-10 elemental concentrations. Based on multiple linear regression analysis, the contribution of traffic emissions (27%) to PM2.5 was found to be higher than mineral dust (23%), marine aerosol (18%), and industrial emissions (8%). On the other hand, mineral dust was the dominant source of PM2.5-10 with 45% contribution, followed by marine aerosol (22%), and traffic emissions (19%). This study provides novel insight into the spatial variation of traffic-related elements in a large metropolitan area.
Collapse
Affiliation(s)
- Farzan Oroumiyeh
- Department of Environmental Health Sciences, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Michael Jerrett
- Department of Environmental Health Sciences, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Irish Del Rosario
- Department of Epidemiology, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Jonah Lipsitt
- Department of Environmental Health Sciences, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Jonathan Liu
- Department of Environmental Health Sciences, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Suzanne E Paulson
- Department of Atmospheric & Oceanic Sciences, University of California, Los Angeles, CA, 90095, USA
| | - Beate Ritz
- Department of Epidemiology, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - James J Schauer
- Wisconsin State Laboratory of Hygiene, School of Medicine & Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - Martin M Shafer
- Wisconsin State Laboratory of Hygiene, School of Medicine & Public Health, University of Wisconsin-Madison, Madison, WI, USA
| | - Jiaqi Shen
- Department of Atmospheric & Oceanic Sciences, University of California, Los Angeles, CA, 90095, USA
| | - Scott Weichenthal
- Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, Quebec, Canada
| | - Sudipto Banerjee
- Department of Biostatistics, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Yifang Zhu
- Department of Environmental Health Sciences, Jonathan and Karin Fielding School of Public Health, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
| |
Collapse
|
6
|
Sadeghpour A, Oroumiyeh F, Zhu Y, Ko DD, Ji H, Bertozzi AL, Ju YS. Experimental study of a string-based counterflow wet electrostatic precipitator for collection of fine and ultrafine particles. J Air Waste Manag Assoc 2021; 71:851-865. [PMID: 33395565 DOI: 10.1080/10962247.2020.1869627] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 12/11/2020] [Accepted: 12/14/2020] [Indexed: 06/12/2023]
Abstract
Wet electrostatic precipitators (WESP) have been widely studied for collecting fine and ultrafine particles, such as diesel particulate matter (DPM), which have deleterious effects on human health. Here, we report an experimental and numerical simulation study on a novel string-based two-stage WESP. Our new design incorporates grounded vertically aligned polymer strings, along which thin films of water flow down. The water beads, generated by intrinsic flow instability, travel down the strings and collect charged particles in the counterflowing gas stream. We performed experiments using two different geometric configurations of WESP: rectangular and cylindrical. We examined the effects of the WESP electrode bias voltage, air stream velocity, and water flow rate on the number-based fractional collection efficiency for particles of diameters ranging from 10 nm to 2.5 μm. The collection efficiency improves with increasing bias voltages or decreasing airflow rates. At liquid-to-gas (L/G) as low as approximately 0.0066, our design delivers a collection efficiency over 70% even for fine and ultrafine particles. The rectangular and cylindrical configurations exhibit similar collection efficiencies under nominally identical experimental conditions. We also compare the water-to-air mass flow rate ratio, air flow rate per unit collector volume, and collection efficiency of our string-based design with those of previously reported WESPs. The present work demonstrates a promising design for a highly efficient, compact, and scalable two-stage WESPs with minimal water consumption.Implications: Wet Electrostatic Precipitators (WESPs) are highly effective for collecting fine particles in exhaust air streams from various sources such as diesel engines, power plants, and oil refineries. However, their large-scale adoption has been limited by high water usage and reduced collection efficiencies for ultrafine particles. We perform experimental and numerical investigation to characterize the collection efficiency and water flow rate-dependence of a new design of WESP. The string-based counterflow WESP reported in this study offers number-based collection efficiencies >70% at air flow rates per collector volume as high as 4.36 (m3/s)/m3 for particles of diameters ranging from 10 nm - 2.5 μm, while significantly reducing water usage. Our work provides a basis for the design of more compact and water-efficient WESPs.
Collapse
Affiliation(s)
- Abolfazl Sadeghpour
- Department of Mechanical and Aerospace Engineering, University of California Los Angeles, Los Angeles, USA
| | - Farzan Oroumiyeh
- Department of Environmental Health Sciences, University of California Los Angeles, Los Angeles, USA
| | - Yifang Zhu
- Department of Environmental Health Sciences, University of California Los Angeles, Los Angeles, USA
| | - Danny D Ko
- Department of Mechanical and Aerospace Engineering, University of California Los Angeles, Los Angeles, USA
| | - Hangjie Ji
- Department of Mathematics, University of California Los Angeles, Los Angeles, USA
| | - Andrea L Bertozzi
- Department of Mechanical and Aerospace Engineering, University of California Los Angeles, Los Angeles, USA
- Department of Mathematics, University of California Los Angeles, Los Angeles, USA
| | - Y Sungtaek Ju
- Department of Mechanical and Aerospace Engineering, University of California Los Angeles, Los Angeles, USA
| |
Collapse
|