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Background: Fine particulate matter (PM 2.5 ) exposure is a known risk factor for numerous adverse health outcomes, with varying estimates of component-specific effects. Populations with compromised health conditions such as diabetes can be more sensitive to the health impacts of air pollution exposure. Recent trends in PM 2.5 in primarily American Indian- (AI-) populated areas examined in previous work declined more gradually compared to the declines observed in the rest of the US. To further investigate components contributing to these findings, we compared trends in concentrations of six PM 2.5 components in AI- vs. non-AI-populated counties over time (2000-2017) in the contiguous US., Methods: We implemented component-specific linear mixed models to estimate differences in annual county-level concentrations of sulfate, nitrate, ammonium, organic matter, black carbon, and mineral dust from well-validated surface PM 2.5 models in AI- vs. non-AI-populated counties, using a multi-criteria approach to classify counties as AI- or non-AI-populated. Models adjusted for population density and median household income. We included interaction terms with calendar year to estimate whether concentration differences in AI- vs. non-AI-populated counties varied over time., Results: Our final analysis included 3108 counties, with 199 (6.4%) classified as AI-populated. On average across the study period, adjusted concentrations of all six PM 2.5 components in AI-populated counties were significantly lower than in non-AI-populated counties. However, component-specific levels in AI- vs. non-AI-populated counties varied over time: sulfate and ammonium levels were significantly lower in AI- vs. non-AI-populated counties before 2011 but higher after 2011 and nitrate levels were consistently lower in AI-populated counties., Conclusions: This study indicates time trend differences of specific components by AI-populated county type. Notably, decreases in sulfate and ammonium may contribute to steeper declines in total PM 2.5 in non-AI vs. AI-populated counties. These findings provide potential directives for additional monitoring and regulations of key emissions sources impacting tribal lands., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Few studies have evaluated Electronic Nicotine Delivery Systems (ENDS) in longitudinal studies, as a potential source of metals which may have carcinogenic, neurotoxic, and cardiotoxic effects. We evaluated metal body burden by ENDS use status in a longitudinal population-based national survey., Methods: We used the Population Assessment of Tobacco and Health (PATH) Study wave 1 (2013-2014), wave 2 (2014-2015), and wave 3 (2015-2016) adult data to assess urinary concentrations of seven metals among (1) ENDS only users who never used any nonelectronic tobacco products (n = 50), (2) ENDS only users who were former users of any nonelectronic tobacco products (n = 123) and (3) Never users (n = 1501) of any tobacco product., Results: Among ENDS only users who never used any nonelectronic tobacco products (n = 50), the geometric mean ratios (GMRs) of Cd and Pb were 1.25 (95%CI: 1.09-1.42) and 1.19 (95%CI: 1.05-1.34), respectively, compared to never users after adjustment for PATH Study wave, age, sex, race/ethnicity, education, region, secondhand smoke at home and work, and cannabis and other substance use. After the same adjustment, the corresponding GMRs were 1.48 (95%CI: 1.32-1.67) and 1.43 (95%CI: 1.28-1.60) for ENDS only users who were former users of any nonelectronic tobacco products (n = 123). No difference was observed in urinary concentrations of other metals comparing ENDS users to never users of any tobacco product., Discussion: ENDS users show higher urinary levels of Cd and Pb, including lifetime exclusive ENDS users compared to never users of any tobacco product. These findings are limited by the small sample size and could be related to underreporting of past combustible tobacco use or other factors. Metals typical of ENDS such as nickel and chromium unfortunately are not available in PATH. Studies assessing metal exposure associated with long term lifetime exclusive ENDS use (≥5 years) with larger sample size are needed., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: The waterfront in the South Bronx in New York City is used industrially and harbors the Harlem River Yards (HRY). The HRY borders an environmental justice area, which includes a mixed-use area that is separated from a densely populated residential area by interstates. Recently, development of the HRY has expanded including the 2018 opening of a large online store warehouse., Objective: The goal of this study was to evaluate trends in traffic congestion nearby the HRY between 2017 to 2019., Methods: We analyzed one-hourly time series of crowd-sensed traffic congestion maps, both at the neighborhood scale and the road stretch level. Traffic radar measurements at two locations did not indicate bias in the crowd-sensed data over the study period, i.e., changed mappings between vehicle speed and the reported congestion., Results: In the mixed-use areas, traffic congestion increased significantly during all hours of the day, with greatest increases at night and in the morning. Congestion increased close to the entrances of the HRY and along routes used by pedestrians and bicyclists to access a nearby recreational area. In the residential area, congestion increased significantly from midnight to morning and was unchanged for the remainder of the day. On the interstates, congestion decreased during the daytime but increased at night., Conclusions: Neighborhood-scale traffic congestion increased in mixed-use and residential areas in an environmental justice community. Our methods can be applied globally as long as crowd-sensed traffic data can be acquired. The data enable communities to advocate for mitigating measures., Competing Interests: CONFLICT OF INTEREST We declare no competing interests.

Vaping is the action of inhaling and exhaling aerosols from electronic cigarettes. The aerosols contain various amounts of toxic chemicals, including metals. The purpose of this study was to evaluate factors that can influence metal levels, including flavor and nicotine content in the e-liquid, and puff duration. Aerosols were collected from both closed-system (cartridge-based) and open-system e-cigarettes using e-liquids with different flavors (fruit, tobacco, and menthol), nicotine content (0, 6, 24, and 59 mg/mL), and different puff durations (1, 2, and 4 s). The concentrations of 14 metals in the collected aerosols were measured using inductively coupled plasma mass spectroscopy. Aerosol concentrations of As, Fe, and Mn varied significantly among fruit, tobacco, and menthol flavors in both closed-system and open-system devices. Concentrations of Al, Fe, Sn, and U were significantly higher in tobacco or menthol flavored aerosols compared to fruit flavors in closed-system devices. Aerosol W levels were significantly higher in tobacco flavored aerosols compared to fruit flavors in open-system devices. Concentrations of As, Fe, and Mn were higher in tobacco flavored aerosols compared to menthol flavors in both types of devices. The median Pb concentration decreased significantly from 15.8 to 0.88 μg/kg when nicotine content increased from 0 to 59 mg/mL, and median Ni concentration was 9.60 times higher in aerosols with nicotine of 59 mg/mL compared to 24 mg/mL (11.9 vs. 1.24 μg/kg) for closed-system devices. No significant differences were observed in aerosol metal concentrations for different puff durations. Aerosol metal concentrations varied widely between different flavors and nicotine content but not by puff duration. Flavor and nicotine content of the e-liquid could be potential factors in metal emissions. Some elements showed higher concentrations under certain conditions, highlighting the urgent need of developing strict product regulations, especially on e-liquid composition and nicotine content to inform e-cigarette users about metal exposure through vaping., (Copyright © 2021 Elsevier Inc. All rights reserved.)

The use of electronic cigarettes (e-cigarettes) has increased due to the belief that they are healthier than tobacco cigarettes. E-cigarettes contain a metallic heating coil (composed of Ni, Cr, Al and other metals) to heat a solution (commonly called e-liquid) and convert it into an aerosol. This aerosol is inhaled (vaped) by the users who can be potentially exposed to a wide variety of metals. We investigated the possible transfer of metals from the coil to the e-liquid and the generated aerosol, and how the exposure to this aerosol can increase metal body burden in e-cigarette users. We recruited 75 e-cigarette users (50 who only vaped and 25 dual users who vaped and smoked) and 25 controls who neither vaped nor smoked. E-liquid samples before (dispenser e-liquid) and after (tank e-liquid) being added to their devices were collected. Aerosol samples were collected using a condensation method. All participants provided urine and hair samples. All samples were analyzed for metals by ICP-MS. We observed higher metal concentrations in the aerosol and tank e-liquid (in contact with the coil) compared to the dispenser e-liquid (before contact with the coil). The median concentrations for some of the metals with the most remarkable increases in aerosol and tank e-liquid vs. dispenser e-liquid were 36.90 and 62.73 vs. 18.29 μg/kg for Al; 6.71 and 28.97 vs. 0.98 μg/kg for Cr; 91.39 and 414.47 vs. 1.64 μg/kg for Ni; 738.99 and 744.24 vs. 16.56 μg/kg for Zn; and 10.17 and 22.31 vs. 0.88 μg/kg for Pb. We also found detectable and potentially high concentrations of other metals such as Mn, Cu, Sb and Sn. In urine, increases in the median levels (μg/g creatinine) in vapers/duals vs. controls were observed for some metals, including Cr (0.34/0.28 vs. 0.20), Cu (1.72/2.36 vs. 1.46), Sn (0.26/0.31 vs. 0.18) and Pb (0.39/0.44 vs. 0.22). In hair, there were no differences in metal concentrations among the three groups. In conclusion, e-cigarettes are likely a source of metals such as Cr, Cu, Ni, Pb or Sn. These metals come from the device, likely the heating resistance, as their concentrations were low in the dispenser e-liquid and higher in the aerosol and the e-liquid left in the tank. Although the exposure to e-cigarette aerosol can have an influence in the body burden of metals, aerosol metal levels were not clearly associated with metal levels in biological samples such as urine or hair in e-cigarette users in this study., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Despite a recent increase in e-cigarette use, the adverse human health effects of exposure to e-cigarette aerosol, especially on the central nervous system (CNS), remain unclear. Multiple neurotoxic metals have been identified in e-cigarette aerosol. However, it is unknown whether those metals accumulate in the CNS at biologically meaningful levels. To answer this question, two groups of mice were whole-body exposed twice a day, 5 days a week, for two months, to either a dose of e-cigarette aerosol equivalent to human secondhand exposure, or a 5-fold higher dose. After the last exposure, the olfactory bulb, anterior and posterior frontal cortex, striatum, ventral midbrain, cerebellum, brainstem, remaining brain tissue and spinal cord were collected for metal quantification by inductively coupled plasma mass spectrometry and compared to tissues from unexposed control mice. The two-month exposure caused significant accumulation of several neurotoxic metals in various brain areas - for some metals even at the low exposure dose. The most striking increases were measured in the striatum. For several metals, including Cr, Cu, Fe, Mn, and Pb, similar accumulations are known to be neurotoxic in mice. Decreases in some essential metals were observed across the CNS. Our findings suggest that chronic exposure to e-cigarette aerosol could lead to CNS neurotoxic metal deposition and endogenous metal dyshomeostasis, including potential neurotoxicity. We conclude that e-cigarette-mediated metal neurotoxicity may pose long-term neurotoxic and neurodegenerative risks for e-cigarette users and bystanders., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Introduction: To mitigate the COVID-19 pandemic and prevent overwhelming the healthcare system, social-distancing policies such as school closure, stay-at-home orders, and indoor dining closure have been utilized worldwide. These policies function by reducing the rate of close contact within populations and result in decreased human mobility. Adherence to social distancing can substantially reduce disease spread. Thus, quantifying human mobility and social-distancing compliance, especially at high temporal resolution, can provide great insight into the impact of social distancing policies., Methods: We used the movement of individuals around New York City (NYC), measured via traffic levels, as a proxy for human mobility and the impact of social-distancing policies (i.e., work from home policies, school closure, indoor dining closure etc.). By data mining Google traffic in real-time, and applying image processing, we derived high resolution time series of traffic in NYC. We used time series decomposition and generalized additive models to quantify changes in rush hour/non-rush hour, and weekday/weekend traffic, pre-pandemic and following the roll-out of multiple social distancing interventions., Results: Mobility decreased sharply on March 14, 2020 following declaration of the pandemic. However, levels began rebounding by approximately April 13, almost 2 months before stay-at-home orders were lifted, indicating premature increase in mobility, which we term social-distancing fatigue. We also observed large impacts on diurnal traffic congestion, such that the pre-pandemic bi-modal weekday congestion representing morning and evening rush hour was dramatically altered. By September, traffic congestion rebounded to approximately 75% of pre-pandemic levels., Conclusion: Using crowd-sourced traffic congestion data, we described changes in mobility in Manhattan, NYC, during the COVID-19 pandemic. These data can be used to inform human mobility changes during the current pandemic, in planning for responses to future pandemics, and in understanding the potential impact of large-scale traffic interventions such as congestion pricing policies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Electronic cigarettes (E-cigarettes) generate aerosol containing metal contaminants. Our goals were to quantify aerosol metal concentrations and to compare the effects of power setting and device type (closed-system vs. open-system) on metal release., Methods: Aerosol samples were collected from two closed-system devices (a cigalike and pod) and two open-system devices (mods). Each open-system device was operated at three different power settings to examine the effect of device power on metal release. Concentrations of 14 metals in e-cigarette aerosol collected via droplet deposition were measured using inductively coupled plasma mass spectroscopy. Aerosol metal concentrations were reported as mass fractions (μg/kg) in the e-liquid., Results: For open-system device 1 (OD1), median arsenic (As), chromium (Cr), copper (Cu), iron (Fe), manganese (Mn), nickel (Ni), lead (Pb), antimony (Sb), tin (Sn), and zinc (Zn) concentrations increased 14, 54, 17, 30, 41, 96, 14, 81, 631, and 7-fold when the device power was increased from low (20 W) to intermediate (40 W) setting. When the power was further increased from intermediate (40 W) to high (80 W) setting, concentrations of As, Cr, Cu, Mn, Ni, and Sb did not change significantly. For open-system device 2 (OD2), Cr and Mn concentrations increased significantly when device power was increased from low (40 W) to intermediate (120 W) setting, and then decreased significantly when power was further increased from intermediate (120 W) to high (200 W) setting. Among the four devices, aerosol metal concentrations were higher for the open-system than the closed-system devices, except for aluminum (Al) and uranium (U). For Cr, median (interquartile range) concentrations (μg/kg) from the open-system devices were 2.51 (1.55, 4.23) and 15.6 (7.88, 54.5) vs. 0.39 (0.05, 0.72) and 0.41 (0.34, 0.57) for the closed-system devices. For Ni, concentrations (μg/kg) from the open-system devices were 793 (508, 1169) and 2148 (851, 3397) vs. 1.32 (0.39, 3.35) and 11.9 (10.7, 22.7) from the closed-system devices. Inhalation of 0% and 100% of samples from OD1, 7.4% and 88.9% from OD2 by typical e-cigarette users would exceed chronic minimum risk levels (MRL) of Mn and Ni, respectively. No MRL exceedance was predicted for the closed-system devices. A large fraction of users of OD1 (100%) and OD2 (77.8%) would be exposed to Ni levels higher than those from reference tobacco cigarette 3R4F., Conclusions: Our findings suggest that power setting and device type affect metal release from devices to aerosol which would subsequently be inhaled by users. Metal concentrations from open-system devices first increased with device power, and then leveled off for most metals. Open-system devices generate aerosol with higher metal concentrations than closed-system devices. These findings inform tobacco regulatory science, policy makers and health professionals on potential metal health risks associated with e-cigarette use, design and manufacturing., (Copyright © 2019 Elsevier Inc. All rights reserved.)

At gas stations, fuel vapors are released into the atmosphere from storage tanks through vent pipes. Little is known about when releases occur, their magnitude, and their potential health consequences. Our goals were to quantify vent pipe releases and examine exceedance of short-term exposure limits to benzene around gas stations. At two US gas stations, we measured volumetric vent pipe flow rates and pressure in the storage tank headspace at high temporal resolution for approximately three weeks. Based on the measured vent emission and meteorological data, we performed air dispersion modeling to obtain hourly atmospheric benzene levels. For the two gas stations, average vent emission factors were 0.17 and 0.21 kg of gasoline per 1000 L dispensed. Modeling suggests that at one gas station, a 1-hour Reference Exposure Level (REL) for benzene for the general population (8 ppb) was exceeded only closer than 50 m from the station's center. At the other gas station, the REL was exceeded on two different days and up to 160 m from the center, likely due to non-compliant bulk fuel deliveries. A minimum risk level for intermediate duration (>14-364 days) benzene exposure (6 ppb) was exceeded at the elevation of the vent pipe opening up to 7 and 8 m from the two gas stations. Recorded vent emission factors were >10 times higher than estimates used to derive setback distances for gas stations. Setback distances should be revisited to address temporal variability and pollution controls in vent emissions., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Microscale water distribution in the subsurface is key to many geochemical and biogeochemical reactions. This study investigated microscale water distribution and movement in unsaturated soils using micro-continuum hydrodynamic models, and examined the effect of microscale water distribution on organic carbon (C) decomposition using a micro-continuum biogeochemical reaction model. The micro-continuum hydrodynamic model that relates capillary pressure to porosity captured the measured water imbibition curve at the core scale, and exhibited reasonable water distribution and movement at the microscale. The simulations of organic C decomposition illustrate that microscale water distribution strongly affected the distribution of C decomposition rates by regulating the availability of dissolved organic C and oxygen. Particularly, changes in water distribution altered the location and intensity of reactive hotspots and thereby CO 2 flux from soils. The microscale interactions between water content and organic C decomposition rate provide underlying mechanisms for explaining macroscale phenomenon observed in laboratory and fields. Overall, this study presents a useful tool for explicating hydro-biogeochemical behaviors in the subsurface by integrating micro-continuum hydrodynamic and biogeochemical reaction modeling., (Copyright © 2018. Published by Elsevier B.V.)

Small gasoline spills frequently occur at gasoline dispensing stations. We have developed a mathematical model to estimate both the amount of gasoline that infiltrates into the concrete underneath the dispensing stations and the amount of gasoline that evaporates into the typically turbulent atmosphere. Our model shows that the fraction of infiltrated gasoline can exceed the fraction that evaporates from the sessile droplets. Infiltrated gasoline then evaporates and is slowly released to the atmosphere via slow diffusive transport in pores. Tentative experiments show that our theoretical approach captures observed experimental trends. Predictions based on independently estimated model parameters roughly describe the experimental data, except for the very slow vapor release at the end of Stage II evaporation. Our study suggests that, over the lifespan of a gas station, concrete pads underneath gas dispensing stations accumulate significant amounts of gasoline, which could eventually break through into underlying soil and groundwater. Our model also shows that lifetimes of spilled gasoline droplets on concrete surfaces are on the order of minutes or longer. Therefore contamination can be carried away by foot traffic or precipitation runoff. Regulations and guidelines typically do not address subsurface and surface contaminations due to chronic small gasoline spills, even though these spills could result in non-negligible human exposure to toxic and carcinogenic gasoline compounds., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Macrothrombocytopenias are the most important subgroup of inherited thrombocytopenias. This subgroup is particularly heterogeneous because the affected genes are involved in various functions such as cell signaling, cytoskeleton organization, and gene expression. Herein we describe the clinical and hematological features of a consanguineous family with a severe autosomal recessive macrothrombocytopenia associated with a thrombocytopathy inducing a bleeding tendency in the homozygous mutated patients. Platelet activation and cytoskeleton reorganization were impaired in these homozygous patients. Exome sequencing identified a c.222C>G mutation (missense p.74Ile>Met) in PRKACG, a gene encoding the γ-catalytic subunit of the cyclic adenosine monophosphate-dependent protein kinase, the mutated allele cosegregating with the macrothrombocytopenia. We demonstrate that the p.74Ile>Met PRKACG mutation is associated with a marked defect in proplatelet formation and a low level in filamin A in megakaryocytes (MKs). The defect in proplatelet formation was rescued in vitro by lentiviral vector-mediated overexpression of wild-type PRKACG in patient MKs. We thus conclude that PRKACG is a new central actor in platelet biogenesis and a new gene involved in inherited thrombocytopenia with giant platelets associated with a thrombocytopathy., (© 2014 by The American Society of Hematology.)

Traveling bacterial waves are capable of improving contaminant remediation in the subsurface. It is fairly well understood how bacterial chemotaxis and growth separately affect the formation and propagation of such waves. However, their interaction is not well understood. We therefore perform a modeling study to investigate the coupled effects of chemotaxis and growth on bacterial migration, and examine their effects on contaminant remediation. We study the waves by using different initial electron acceptor concentrations for different bacteria and substrate systems. Three types of traveling waves can occur: a chemotactic wave due to the biased movement of chemotactic bacteria resulting from metabolism-generated substrate concentration gradients; a growth/decay/motility wave due to a dynamic equilibrium between bacterial growth, decay and random motility; and an integrated wave due to the interaction between bacterial chemotaxis and growth. Chemotaxis hardly enhances the bacterial propagation if it is too weak to form a chemotactic wave or its wave speed is less than half of the growth/decay/motility wave speed. However, chemotaxis significantly accelerates bacterial propagation once its wave speed exceeds the growth/decay/motility wave speed. When convection occurs, it speeds up the growth/decay/motility wave but slows down or even eliminates the chemotactic wave due to the dispersion. Bacterial survival proves particularly important for bacterial propagation. Therefore we develop a conceptual model to estimate the speed of growth/decay/motility waves., (Copyright © 2014 Elsevier B.V. All rights reserved.)

RUNX1 encodes a DNA-binding α subunit of the core-binding factor, a heterodimeric transcription factor. RUNX1 is a master regulatory gene in hematopoiesis and its disruption is one of the most common aberrations in acute leukemia. Inactivating or dominant-negative mutations in the RUNX1 gene have been also identified in pedigrees of familial platelet disorders with a variable propensity to develop acute myeloid leukemia (FPD/AML). We performed analysis of hematopoiesis from 2 FPD/AML pedigrees with 2 distinct RUNX1 germline mutations, that is, the R139X in a pedigree without AML and the R174Q mutation in a pedigree with AML. Both mutations induced a marked increase in the clonogenic potential of immature CD34(+)CD38(-) progenitors, with some self-renewal capacities observed only for R174Q mutation. This increased proliferation correlated with reduction in the expression of NR4A3, a gene previously implicated in leukemia development. We demonstrated that NR4A3 was a direct target of RUNX1 and that restoration of NR4A3 expression partially reduced the clonogenic potential of patient progenitors. We propose that the down-regulation of NR4A3 in RUNX1-mutated hematopoietic progenitors leads to an increase in the pool of cells susceptible to be hit by secondary leukemic genetic events.

We develop a method to compute interfacial areas from three-dimensional digital representations of multiphase systems. We approximate the interfaces with the isosurface generated by the standard marching-cube algorithm from the discrete phase distribution. We apply this approach to two-fluid pore-scale simulations by (1) simulating a random packing of spheres that obeys the grain-size distribution and porosity of an experimental porous medium system, and (2) using a previously developed pore-morphology-based model in order to predict the phase distribution for a water-wet porous medium that undergoes primary drainage. The predicted primary drainage curve and interfacial areas are in good agreement with the experimental values reported in the literature, where interfacial areas were measured using interfacial tracers. The energy dissipation during Haines jumps is significant: thus, the mechanical work done on the system is not completely converted into surface energy, and interfacial areas may not be deduced from the primary drainage curve.