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1.
Proc Natl Acad Sci U S A ; 121(39): e2401975121, 2024 Sep 24.
Article in English | MEDLINE | ID: mdl-39284062

ABSTRACT

While the dominant role of halogens in Arctic ozone loss during spring has been widely studied in the last decades, the impact of sea-ice halogens on surface ozone abundance over the northern hemisphere (NH) mid-latitudes remains unquantified. Here, we use a state-of-the-art global chemistry-climate model including polar halogens (Cl, Br, and I), which reproduces Arctic ozone seasonality, to show that Arctic sea-ice halogens reduce surface ozone in the NH mid-latitudes (47°N to 60°N) by ~11% during spring. This background ozone reduction follows the southward export of ozone-poor and halogen-rich air masses from the Arctic through polar front intrusions toward lower latitudes, reducing the springtime tropospheric ozone column within the NH mid-latitudes by ~4%. Our results also show that the present-day influence of Arctic halogens on surface ozone destruction is comparatively smaller than in preindustrial times driven by changes in the chemical interplay between anthropogenic pollution and natural halogens. We conclude that the impact of Arctic sea-ice halogens on NH mid-latitude ozone abundance should be incorporated into global models to improve the representation of ozone seasonality.

2.
Natl Sci Rev ; 11(9): nwae285, 2024 Sep.
Article in English | MEDLINE | ID: mdl-39309413

ABSTRACT

Biomass burning (BB) is a major source of trace gases and particles in the atmosphere, influencing air quality, radiative balance, and climate. Previous studies have mainly focused on the BB emissions of carbon and nitrogen species with less attention on chlorine. Reactive chlorine chemistry has significant effects on atmospheric chemistry and air quality. However, quantitative information on chlorine emissions from BB, particularly the long-term trend and associated atmospheric impacts, is limited both on regional and global scales. Here, we report a long-term (2001-2018) high-resolution BB emission inventory for the major chlorine-containing compounds (HCl, chloride, and CH3Cl) in Asia based on satellite observations. We estimate an average of 730 Gg yr-1 chlorine emitted from BB activity in Asia, with China contributing the largest share at 24.2% (177 Gg yr-1), followed by Myanmar at 18.7% and India at 18.3%. Distinct seasonal patterns and significant spatial and interannual variability are observed, mainly driven by human-mediated changes in agricultural activity. By incorporating the newly developed chlorine emission inventory into a global chemistry-climate model (CAM-Chem), we find that the BB-chlorine emissions lead to elevated levels of HCl and CH3Cl (monthly average up to 2062 and 1421 parts per trillion by volume (pptv), respectively), subsequently resulting in noticeable changes in oxidants (up to 3.1% in O3 and 17% in OH radicals). The results demonstrate that BB is not only a significant source of air pollutants but also of oxidants, suggesting a larger role of BB emissions in the atmospheric chemistry and oxidation process than previously appreciated. In light of the projected increase in BB activity toward the end of the century and the extensive control of anthropogenic emissions worldwide, the contribution of BB emissions may become fundamental to air quality composition in the future.

3.
Natl Sci Rev ; 11(4): nwae074, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38623452

ABSTRACT

Tropospheric reactive bromine is important for atmospheric chemistry, regional air pollution, and global climate. Previous studies have reported measurements of atmospheric reactive bromine species in different environments, and proposed their main sources, e.g. sea-salt aerosol (SSA), oceanic biogenic activity, polar snow/ice, and volcanoes. Typhoons and other strong cyclonic activities (e.g. hurricanes) induce abrupt changes in different earth system processes, causing widespread destructive effects. However, the role of typhoons in regulating reactive bromine abundance and sources remains unexplored. Here, we report field observations of bromine oxide (BrO), a critical indicator of reactive bromine, on the Huaniao Island (HNI) in the East China Sea in July 2018. We observed high levels of BrO below 500 m with a daytime average of 9.7 ± 4.2 pptv and a peak value of ∼26 pptv under the influence of a typhoon. Our field measurements, supported by model simulations, suggest that the typhoon-induced drastic increase in wind speed amplifies the emission of SSA, significantly enhancing the activation of reactive bromine from SSA debromination. We also detected enhanced BrO mixing ratios under high NOx conditions (ppbv level) suggesting a potential pollution-induced mechanism of bromine release from SSA. Such elevated levels of atmospheric bromine noticeably increase ozone destruction by as much as ∼40% across the East China Sea. Considering the high frequency of cyclonic activity in the northern hemisphere, reactive bromine chemistry is expected to play a more important role than previously thought in affecting coastal air quality and atmospheric oxidation capacity. We suggest that models need to consider the hitherto overlooked typhoon- and pollution-mediated increase in reactive bromine levels when assessing the synergic effects of cyclonic activities on the earth system.

4.
Proc Natl Acad Sci U S A ; 121(12): e2315058121, 2024 Mar 19.
Article in English | MEDLINE | ID: mdl-38466839

ABSTRACT

Mercury (Hg) is a contaminant of global concern, and an accurate understanding of its atmospheric fate is needed to assess its risks to humans and ecosystem health. Atmospheric oxidation of Hg is key to the deposition of this toxic metal to the Earth's surface. Short-lived halogens (SLHs) can provide halogen radicals to directly oxidize Hg and perturb the budget of other Hg oxidants (e.g., OH and O3). In addition to known ocean emissions of halogens, recent observational evidence has revealed abundant anthropogenic emissions of SLHs over continental areas. However, the impacts of anthropogenic SLHs emissions on the atmospheric fate of Hg and human exposure to Hg contamination remain unknown. Here, we show that the inclusion of anthropogenic SLHs substantially increased local Hg oxidation and, consequently, deposition in/near Hg continental source regions by up to 20%, thereby decreasing Hg export from source regions to clean environments. Our modeling results indicated that the inclusion of anthropogenic SLHs can lead to higher Hg exposure in/near Hg source regions than estimated in previous assessments, e.g., with increases of 8.7% and 7.5% in China and India, respectively, consequently leading to higher Hg-related human health risks. These results highlight the urgent need for policymakers to reduce local Hg and SLHs emissions. We conclude that the substantial impacts of anthropogenic SLHs emissions should be included in model assessments of the Hg budget and associated health risks at local and global scales.


Subject(s)
Mercury , Humans , Mercury/toxicity , Mercury/analysis , Environmental Monitoring/methods , Ecosystem , China , India
5.
Virol J ; 20(1): 207, 2023 09 07.
Article in English | MEDLINE | ID: mdl-37679779

ABSTRACT

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection induces a spectrum of clinical manifestations that depend on the immune response of the patient, i.e., from an asymptomatic form to an inflammatory response with multiorgan deterioration. In some cases, severe cases of SARS-CoV-2 are characterized by an excessive, persistent release of inflammatory mediators known as a cytokine storm. This phenomenon arises from an ineffective T helper (Th)-1 response, which is unable to control the infection and leads to a reinforcement of innate immunity, causing tissue damage. The evolution of the disease produced by SARS-CoV2, known as COVID-19, has been of interest in several research fields. Asthma patients have been reported to present highly variable outcomes due to the heterogeneity of the disease. For example, the Th2 response in patients with allergic asthma is capable of decreasing Th1 activation in COVID-19, preventing the onset of a cytokine storm; additionally, IL-33 released by damaged epithelium in the context of COVID-19 potentiates either Th1 or T2-high responses, a process that contributes to poor outcomes. IL-13, a T2-high inflammatory cytokine, decreases the expression of angiotensin converting enzyme-2 (ACE2) receptor, hindering SARS-CoV-2 entry; finally, poor outcomes have been observed in COVID-19 patients with severe neutrophilic asthma. In other contexts, the COVID-19 lockdown has had interesting effects on asthma epidemiology. The incidence of asthma in the most populated states in Mexico, including Tamaulipas, which has the highest asthma incidence in the country, showed similar tendencies independent of how strict the lockdown measures were in each state. As described worldwide for various diseases, a decrease in asthma cases was observed during the COVID-19 lockdown. This decrease was associated with a drop in acute respiratory infection cases. The drop in cases of various diseases, such as diabetes, hypertension or depression, observed in 2020 was restored in 2022, but not for asthma and acute respiratory infections. There were slight increases in asthma cases when in-person classes resumed. In conclusion, although many factors were involved in asthma outcomes during the pandemic, it seems that acute respiratory infection is intimately linked to asthma cases. Social distancing during remote learning, particularly school lockdown, appears to be an important cause of the decrease in cases.


Subject(s)
Asthma , COVID-19 , Humans , COVID-19/epidemiology , SARS-CoV-2 , Cytokine Release Syndrome/epidemiology , RNA, Viral , Communicable Disease Control , Asthma/epidemiology
6.
J Adolesc ; 95(8): 1603-1616, 2023 12.
Article in English | MEDLINE | ID: mdl-37583064

ABSTRACT

PURPOSE: This study examines the relationship between social support and victimization of Latino youth over time, utilizing the stress prevention and support deterioration models. METHODS: To address the research questions we utilized data from Waves 1 and 2 (n = 574) of the Dating Violence among Latino Adolescents (DAVILA) study, a national bilingual phone survey of self-identified Latino youth and their caregiver. Cross-lagged panel modeling was used to assess the fit of the two theoretical models to observed patterns of covariance among the victimization and social support variables specified. RESULTS: Results show that victimization at Wave 1 was positively and strongly related to victimization at Wave 2 and social support at Wave 1 was positively and moderately associated with social support at Wave 2. As hypothesized, higher levels of victimization at Wave 1 were significantly related to decreases in social support at Wave 2 (ß = -.15). Wave 1 social support was not significantly related to victimization at Wave 2. CONCLUSIONS: We did not find support for the stress prevention model but did find support for the support deterioration model. Teens who were victimized tended to have lower levels of subsequent social support, highlighting the need to equip peers, family, and significant others to adequately respond to victimization disclosures.


Subject(s)
Crime Victims , Social Support , Adolescent , Humans , Hispanic or Latino
7.
Proc Natl Acad Sci U S A ; 120(31): e2303974120, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37487065

ABSTRACT

Active chlorine in the atmosphere is poorly constrained and so is its role in the oxidation of the potent greenhouse gas methane, causing uncertainty in global methane budgets. We propose a photocatalytic mechanism for chlorine atom production that occurs when Sahara dust mixes with sea spray aerosol. The mechanism is validated by implementation in a global atmospheric model and thereby explaining the episodic, seasonal, and location-dependent 13C depletion in CO in air samples from Barbados [J.E. Mak, G. Kra, T. Sandomenico, P. Bergamaschi, J. Geophys. Res. Atmos. 108 (2003)], which remained unexplained for decades. The production of Cl can also explain the anomaly in the CO:ethane ratio found at Cape Verde [K. A. Read et al., J. Geophys. Res. Atmos. 114 (2009)], in addition to explaining the observation of elevated HOCl [M. J. Lawler et al., Atmos. Chem. Phys. 11, 7617-7628 (2011)]. Our model finds that 3.8 Tg(Cl) y-1 is produced over the North Atlantic, making it the dominant source of chlorine in the region; globally, chlorine production increases by 41%. The shift in the methane sink budget due to the increased role of Cl means that isotope-constrained top-down models fail to allocate 12 Tg y-1 (2% of total methane emissions) to 13C-depleted biological sources such as agriculture and wetlands. Since 2014, an increase in North African dust emissions has increased the 13C isotope of atmospheric CH4, thereby partially masking a much greater decline in this isotope, which has implications for the interpretation of the drivers behind the recent increase of methane in the atmosphere.

8.
Nat Commun ; 14(1): 4045, 2023 Jul 08.
Article in English | MEDLINE | ID: mdl-37422475

ABSTRACT

Atmospheric methane is both a potent greenhouse gas and photochemically active, with approximately equal anthropogenic and natural sources. The addition of chlorine to the atmosphere has been proposed to mitigate global warming through methane reduction by increasing its chemical loss. However, the potential environmental impacts of such climate mitigation remain unexplored. Here, sensitivity studies are conducted to evaluate the possible effects of increasing reactive chlorine emissions on the methane budget, atmospheric composition and radiative forcing. Because of non-linear chemistry, in order to achieve a reduction in methane burden (instead of an increase), the chlorine atom burden needs to be a minimum of three times the estimated present-day burden. If the methane removal target is set to 20%, 45%, or 70% less global methane by 2050 compared to the levels in the Representative Concentration Pathway 8.5 scenario (RCP8.5), our modeling results suggest that additional chlorine fluxes of 630, 1250, and 1880 Tg Cl/year, respectively, are needed. The results show that increasing chlorine emissions also induces significant changes in other important climate forcers. Remarkably, the tropospheric ozone decrease is large enough that the magnitude of radiative forcing decrease is similar to that of methane. Adding 630, 1250, and 1880 Tg Cl/year to the RCP8.5 scenario, chosen to have the most consistent current-day trends of methane, will decrease the surface temperature by 0.2, 0.4, and 0.6 °C by 2050, respectively. The quantity and method in which the chlorine is added, its interactions with climate pathways, and the potential environmental impacts on air quality and ocean acidity, must be carefully considered before any action is taken.


Subject(s)
Air Pollution , Ozone , Chlorine , Methane/analysis , Climate , Air Pollution/analysis , Ozone/analysis , Atmosphere/chemistry , Halogens
9.
Nature ; 618(7967): 967-973, 2023 Jun.
Article in English | MEDLINE | ID: mdl-37380694

ABSTRACT

Observational evidence shows the ubiquitous presence of ocean-emitted short-lived halogens in the global atmosphere1-3. Natural emissions of these chemical compounds have been anthropogenically amplified since pre-industrial times4-6, while, in addition, anthropogenic short-lived halocarbons are currently being emitted to the atmosphere7,8. Despite their widespread distribution in the atmosphere, the combined impact of these species on Earth's radiative balance remains unknown. Here we show that short-lived halogens exert a substantial indirect cooling effect at present (-0.13 ± 0.03 watts per square metre) that arises from halogen-mediated radiative perturbations of ozone (-0.24 ± 0.02 watts per square metre), compensated by those from methane (+0.09 ± 0.01 watts per square metre), aerosols (+0.03 ± 0.01 watts per square metre) and stratospheric water vapour (+0.011 ± 0.001 watts per square metre). Importantly, this substantial cooling effect has increased since 1750 by -0.05 ± 0.03 watts per square metre (61 per cent), driven by the anthropogenic amplification of natural halogen emissions, and is projected to change further (18-31 per cent by 2100) depending on climate warming projections and socioeconomic development. We conclude that the indirect radiative effect due to short-lived halogens should now be incorporated into climate models to provide a more realistic natural baseline of Earth's climate system.


Subject(s)
Atmosphere , Climate Change , Climate Models , Climate , Cold Temperature , Halogens , Atmosphere/analysis , Atmosphere/chemistry , Halogens/analysis , Hydrocarbons, Halogenated , Oceans and Seas , Seawater/analysis , Seawater/chemistry , Climate Change/statistics & numerical data , Human Activities
10.
J Interpers Violence ; 38(17-18): 9898-9922, 2023 09.
Article in English | MEDLINE | ID: mdl-37191323

ABSTRACT

The present study examined factors that could be associated with bias victimization according to intergroup threat theory, namely socioeconomic status (SES), acculturation (Anglo orientation and Latino orientation), immigrant status, and their interactions. Self-identified Latino participants (N = 910) from three cities in the United States were queried about experiences with bias victimization, specifically hate crime and noncriminal bias victimization. Findings revealed that levels of bias victimization, hate crime, and noncriminal bias victimization were associated with SES, Anglo orientation, immigrant status, and their interactions, although in some unpredicted ways. Interactions among key variables helped clarify the roles of these factors in concert on bias victimization. The hate crimes against U.S.-born Latinos and the victimization risk associated with increasing Anglo orientations among immigrants contradicts predictions of intergroup threat theory. More nuanced analyses of social locations are needed to examine bias victimization.


Subject(s)
Crime Victims , Emigrants and Immigrants , Humans , United States , Acculturation , Economic Status , Hispanic or Latino , Social Class
11.
Sci Adv ; 9(4): eadd9031, 2023 Jan 27.
Article in English | MEDLINE | ID: mdl-36706174

ABSTRACT

Reactive trace gas emissions from the polar oceans are poorly characterized, even though their effects on atmospheric chemistry and aerosol formation are crucial for assessing current and preindustrial aerosol forcing on climate. Here, we present seawater and atmospheric measurements of benzene and toluene, two gases typically associated with pollution, in the remote Southern Ocean and the Arctic marginal ice zone. Their distribution suggests a marine biogenic source. Calculated emission fluxes were 0.023 ± 0.030 (benzene) and 0.039 ± 0.036 (toluene) and 0.023 ± 0.028 (benzene) and 0.034 ± 0.041 (toluene) µmol m-2 day-1 for the Southern Ocean and the Arctic, respectively. Including these average emissions in a chemistry-climate model increased secondary organic aerosol mass concentrations only by 0.1% over the Arctic but by 7.7% over the Southern Ocean, with transient episodes of up to 77.3%. Climate models should consider the hitherto overlooked emissions of benzene and toluene from the polar oceans.

12.
Psychol Trauma ; 15(1): 60-72, 2023 Jan.
Article in English | MEDLINE | ID: mdl-35951412

ABSTRACT

OBJECTIVE: The aim of the current paper is to provide an applied introduction and overview of Bayesian methodology, how it compares from commonly used frequentist methods, and to elaborate on the utility of Bayesian methods in trauma and mental health research. METHOD: Using data from the second wave of the Longitudinal Examination of Victimization Experiences of Latinos (LEVEL) study (N = 323) we ran frequentist modeling using OLS regression to test the effects of lifetime victimization, hate crime, and noncriminal bias events on anxiety, depression, anger, and dissociation. For the Bayesian analyses, we replicate these regressions using both weakly informative and highly informative priors, as well as a likelihood function that addresses data skew. RESULTS: Results across the 3 analyses present some key differences. In the frequentist models we find that lifetime victimization, hate crime, and noncriminal bias events had significant and positive relationship with anxiety, depression, and anger. Only hate crimes were significantly related to dissociation. The Bayesian results change based on which priors were implemented into the models. Ultimately, the results differ both across methodologies and within the Bayesian methodology depending on type of prior used. CONCLUSIONS: Several meaningful differences between the approaches emerge resulting in different interpretations of these results. Bayesian analyses serve as an additional tool for researchers that can be used to answer new and unique research questions that may be inaccessible by frequentist methods. (PsycInfo Database Record (c) 2023 APA, all rights reserved).


Subject(s)
Crime Victims , Humans , Adult , Bayes Theorem , Crime Victims/psychology , Crime , Likelihood Functions
13.
Geophys Res Lett ; 49(6): e2021GL097567, 2022 Mar 28.
Article in English | MEDLINE | ID: mdl-35859565

ABSTRACT

Heterogeneous uptake of hypoiodous acid (HOI), the dominant inorganic iodine species in the marine boundary layer (MBL), on sea-salt aerosol (SSA) to form iodine monobromide and iodine monochloride has been adopted in models with assumed efficiency. Recently, field measurements have reported a much faster rate of this recycling process than previously assumed in models. Here, we conduct global model simulations to quantify the range of effects of iodine recycling within the MBL, using Conventional, Updated, and Upper-limit coefficients. When considering the Updated coefficient, iodine recycling significantly enhances gaseous inorganic iodine abundance (∼40%), increases halogen atom production rates (∼40% in I, >100% in Br, and ∼60% in Cl), and reduces oxidant levels (-7% in O3, -2% in OH, and -4% in HO2) compared to the simulation without the process. We appeal for further direct measurements of iodine species, laboratory experiments on the controlling factors, and multiscale simulations of iodine heterogeneous recycling.

14.
Geophys Res Lett ; 49(12): e2022GL097953, 2022 Jun 28.
Article in English | MEDLINE | ID: mdl-35860422

ABSTRACT

Mercury, a global contaminant, enters the stratosphere through convective uplift, but its chemical cycling in the stratosphere is unknown. We report the first model of stratospheric mercury chemistry based on a novel photosensitized oxidation mechanism. We find two very distinct Hg chemical regimes in the stratosphere: in the upper stratosphere, above the ozone maximum concentration, Hg0 oxidation is initiated by photosensitized reactions, followed by second-step chlorine chemistry. In the lower stratosphere, ground-state Hg0 is oxidized by thermal reactions at much slower rates. This dichotomy arises due to the coincidence of the mercury absorption at 253.7 nm with the ozone Hartley band maximum at 254 nm. We also find that stratospheric Hg oxidation, controlled by chlorine and hydroxyl radicals, is much faster than previously assumed, but moderated by efficient photo-reduction of mercury compounds. Mercury lifetime shows a steep increase from hours in the upper-middle stratosphere to years in the lower stratosphere.

15.
J Geophys Res Atmos ; 127(4): e2021JD036081, 2022 Feb 27.
Article in English | MEDLINE | ID: mdl-35865333

ABSTRACT

We have compiled and analyzed a comprehensive data set of field observations of iodine speciation in marine aerosol. The soluble iodine content of fine aerosol (PM1) is dominated by soluble organic iodine (SOI; ∼50%) and iodide (∼30%), while the coarse fraction is dominated by iodate (∼50%), with nonnegligible amounts of iodide (∼20%). The SOI fraction shows an equatorial maximum and minima coinciding with the ocean "deserts," which suggests a link between soluble iodine speciation in aerosol and ocean productivity. Among the major aerosol ions, organic anions and non-sea-salt sulfate show positive correlations with SOI in PM1. Alkali cations are positively correlated to iodate and negatively correlated with SOI and iodide in coarse aerosol. These relationships suggest that under acidic conditions iodate is reduced to HOI, which reacts with organic matter to form SOI, a possible source of iodide. In less acidic sea-salt or dust-rich coarse aerosols, HOI oxidation to iodate and reaction with organic matter likely compete.

16.
BMC Pediatr ; 22(1): 337, 2022 06 10.
Article in English | MEDLINE | ID: mdl-35689198

ABSTRACT

BACKGROUND: Dating abuse (DA) is prevalent and consequential, but no brief DA screening tools are available for use in pediatric or other settings. This study was designed to determine the sensitivity, specificity, and predictive values of the MARSHA-C, which is a three-item DA victimization screening tool. METHODS: The participants were 224 U.S. youth ages 11-21 years old (20% male, 77% female, 3% non-binary gender). Youth completed an online questionnaire about adolescent relationship abuse. The survey included the Measure of Adolescent Relationship Harassment and Abuse (MARSHA), which is a comprehensive DA measurement instrument normed on a nationally representative sample. Of 34 DA victimization items from the MARSHA, the three most prevalent items were hypothesized to have good predictive validity of the full scale score as a brief, screening version (MARSHA-C). The sensitivity, specificity, positive predictive value, and negative predictive value of the MARSHA-C to identify victims of DA was calculated. RESULTS: Using the MARSHA as the reference standard, the cutpoint of 1 on the MARSHA-C screening tool was identified as optimal. The MARSHA-C had a sensitivity of 84%, a specificity of 91%, and positive predictive value of 91%. Thus, for youth who endorse ≥ 1 MARSHA-C items, there is a 91% probability that they have experienced DA in the past year. Exploratory analyses by demographic subgroups suggest that the predictive validity of the MARSHA-C is approximately equivalent for females and males, younger and older adolescents, Asian, Black, Latinx, Multiracial and White youth, and heterosexual and lesbian, gay, and bisexual youth. CONCLUSIONS: The MARSHA-C can be used to detect DA among 11-21-year-old youth via online surveys for research purposes, or in clinical care settings to facilitate proactive patient counseling or parent-oriented anticipatory guidance.


Subject(s)
Bullying , Crime Victims , Adolescent , Adult , Child , Crime Victims/psychology , Female , Humans , Male , Parents , Surveys and Questionnaires , Young Adult
17.
Sci Total Environ ; 839: 156268, 2022 Sep 15.
Article in English | MEDLINE | ID: mdl-35643146

ABSTRACT

Airborne dust represents a hazard to the environment and human health. The outflow of air masses carrying dust from northern Africa, the world's largest active dust source, to the North Atlantic and Mediterranean regions is modulated by atmospheric conditions. However, how global warming-driven changes on atmospheric circulation have influenced North African air outflow in the recent past is not well understood. Here, we explore the Saharan air outflow from northwestern Africa over the 1980 to 2020 period. We find a decrease in the transport to the Atlantic Ocean and the Iberian Peninsula of -0.29 ± 0.16% dec-1 and -0.66 ± 0.18% dec-1, respectively, and an increasing trend to the Mediterranean Sea (0.24 ± 0.18% dec-1) and Europe (0.60 ± 0.18% dec-1). The results indicate that the strengthening of the Atlantic high pressure system and the Saharan thermal low, both associated with the narrowing of the Intertropical Convergence Zone and the Hadley Cell expansion under global warming, could be favoring the Saharan outflow to the Mediterranean Sea and Europe in detriment of transport to the Atlantic Ocean. The results also show that present-day Saharan air arrives at these regions at higher altitudes and in shorter timescales than decades ago. This is associated to the increase in surface heating conditions in the Sahara, 0.41 ± 0.02 °C dec-1, that can inject air into windier upper atmospheric levels, thereby allowing higher and faster air transport. Our results suggest a change in the Saharan air outflow likely associated with global warming and with potentially significant implications for the temporal and spatial patterns of North African dust export.


Subject(s)
Dust , Wind , Africa, Northern , Climate , Dust/analysis , Humans , Mediterranean Region
18.
Nat Commun ; 13(1): 2768, 2022 May 19.
Article in English | MEDLINE | ID: mdl-35589794

ABSTRACT

CH4 is the most abundant reactive greenhouse gas and a complete understanding of its atmospheric fate is needed to formulate mitigation policies. Current chemistry-climate models tend to underestimate the lifetime of CH4, suggesting uncertainties in its sources and sinks. Reactive halogens substantially perturb the budget of tropospheric OH, the main CH4 loss. However, such an effect of atmospheric halogens is not considered in existing climate projections of CH4 burden and radiative forcing. Here, we demonstrate that reactive halogen chemistry increases the global CH4 lifetime by 6-9% during the 21st century. This effect arises from significant halogen-mediated decrease, mainly by iodine and bromine, in OH-driven CH4 loss that surpasses the direct Cl-induced CH4 sink. This increase in CH4 lifetime helps to reduce the gap between models and observations and results in a greater burden and radiative forcing during this century. The increase in CH4 burden due to halogens (up to 700 Tg or 8% by 2100) is equivalent to the observed atmospheric CH4 growth during the last three to four decades. Notably, the halogen-driven enhancement in CH4 radiative forcing is 0.05 W/m2 at present and is projected to increase in the future (0.06 W/m2 by 2100); such enhancement equals ~10% of present-day CH4 radiative forcing and one-third of N2O radiative forcing, the third-largest well-mixed greenhouse gas. Both direct (Cl-driven) and indirect (via OH) impacts of halogens should be included in future CH4 projections.

19.
J Interpers Violence ; 37(23-24): NP23513-NP23526, 2022 12.
Article in English | MEDLINE | ID: mdl-35244476

ABSTRACT

Limited previous research has explored the intersectional stress and trauma sexual minority (SM) Latinx youth experience generated by being part of at least two minoritized groups. The Dating Violence among Latino Adolescents (DAVILA) study employed a national sample of Latinx youth and queried a range of victimizations in the past year, via a bilingual phone survey. Of the 1525 12-18-year-old youth interviewed for DAVILA, 123 either identified as lesbian, gay, or bisexual or had at least one same-sex dating partner. Measures included the Juvenile Victimization Questionnaire, the Conflict Tactics Scale Short Form, Brief Symptom Inventory, and the Multidimensional Scale of Perceived Social Support. Rates of dating violence, psychological dating violence, sexual victimization, and polyvictimization were significantly higher among sexual minority (SM) youth, compared to heterosexual (HET) youth. Victimized SM youth had significantly more depression, anxiety, and hostility than victimized HET youth. Sexual minority youth also reported less social support from family and significant others. A sequential regression showed psychosocial factors of mental health functioning and social support were associated with the number of victimizations above and beyond demographic factors, including SM status. Together these results underscore that SM youth experience greater adverse outcomes than HET youth. However, it is not SM status that directly relates to victimization, but the negative effects of psychological distress and low social support, that account for the higher number of victimizations of SM Latinx youth. These factors are closely linked to the stigmatization that SM youth face. As such efforts to destigmatize SM identities are needed to address the health and safety of SM Latinx youth.


Subject(s)
Bullying , Crime Victims , Homosexuality, Female , Sexual and Gender Minorities , Female , Adolescent , Humans , Crime Victims/psychology , Bullying/psychology , Bisexuality/psychology , Homosexuality, Female/psychology
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