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1.
J Prev (2022) ; 2024 Aug 07.
Artículo en Inglés | MEDLINE | ID: mdl-39110380

RESUMEN

BACKGROUND: Health literacy is essential for individuals to access, understand, and utilize information and services to inform health related decisions and actions. As one of the most diagnosed and preventable forms of cancer, skin cancer disease risk can be reduced through preventative behavior. Currently, there is no focused study looking specifically at health literacy and skin cancer. An understanding of how health literacy affects skin cancer-related preventive behaviors can improve current practices in skin cancer prevention. OBJECTIVE: To systematically identify, synthesize, and summarize findings on the role of health literacy in skin cancers (including cutaneous squamous cell carcinoma, basal cell carcinoma, and melanoma), with a focus on preventive behaviors using studies that utilized quantifiable health literacy measurements. METHODS: A literature search was performed by searching PubMed, Embase, PsycINFO, and CINAHL from inception until September 26, 2023 to identify cross-sectional, case-control, cohort, or randomized controlled studies that investigated the association between health literacy and skin cancer prevention and diagnosis. RESULTS: Health literacy levels varied across geographic regions, specific populations, and ethnicities. Most of the included studies found a positive association between higher health literacy and better skin cancer preventative behaviors. This included sun-protective behaviors such as: wearing sleeved shirts or shirts with collars, using gloves, covering head and face, limiting sun exposure, more sunscreen use, and less sunbathing or indoor tanning. Higher health literacy was associated with increased likelihood to engage in genetic testing and less family influence on health in one study which assessed determinants of interest in skin cancer genetic testing. Another study investigating family communication about skin cancer found that higher health literacy was associated with increased family communication regarding general cancer risk. One sun protection interventional education program was effective at increasing participants' knowledge, awareness of skin cancer risk, willingness to change sun protection, and use of sun protection, but results varied between ethnic groups. CONCLUSIONS: Skin cancer-related educational interventions can be effective in improving health literacy and potentially lessen the impact of skin cancer through positive behavior modification, early detection, and disease knowledge and awareness. Interventions need to be tailored to its target population to maximize effectiveness due to the varying baseline of health literacy identified across different geographic and ethnic groups. Protocol Registration PROSPERO CRD42022340826.

3.
JAAD Int ; 16: 34-38, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-38774346

RESUMEN

Background: Sebaceous carcinoma is a rare cancer, and little is known about its current epidemiology and treatment. This is particularly true for sebaceous carcinomas of the trunk and extremities. Objective: We present a database analysis of sebaceous carcinoma cases to further delineate demographics, location, tumor characteristics, and treatment modalities among patients diagnosed with these tumors. Methods: The National Cancer Database was queried for cases of sebaceous carcinoma between 2004 and 2016. 3211 cases were analyzed for descriptive and comparative statistics. Results: Twenty-six percent of sebaceous carcinomas were found on the trunk and extremities. Tumors on the trunk and extremities were more likely to be larger than tumors on the head and neck, with 8% being greater than 50 mm (P < .001). Tumors on the trunk and extremities were more likely to be well differentiated (P < .001) and have fewer lymph node metastases (P < .001). Surgery was the primary treatment modality for tumors, followed by radiotherapy and rarely chemotherapy. Conclusions: Sebaceous cancer is a poorly understood entity. We demonstrated that trunk and extremity tumors tend to be larger and more differentiated than those of the head and neck. Treatment practices are varied at this time, but surgery is the primary modality.

4.
ACS EST Air ; 1(4): 283-293, 2024 Apr 12.
Artículo en Inglés | MEDLINE | ID: mdl-38633206

RESUMEN

Global ground-level measurements of elements in ambient particulate matter (PM) can provide valuable information to understand the distribution of dust and trace elements, assess health impacts, and investigate emission sources. We use X-ray fluorescence spectroscopy to characterize the elemental composition of PM samples collected from 27 globally distributed sites in the Surface PARTiculate mAtter Network (SPARTAN) over 2019-2023. Consistent protocols are applied to collect all samples and analyze them at one central laboratory, which facilitates comparison across different sites. Multiple quality assurance measures are performed, including applying reference materials that resemble typical PM samples, acceptance testing, and routine quality control. Method detection limits and uncertainties are estimated. Concentrations of dust and trace element oxides (TEO) are determined from the elemental dataset. In addition to sites in arid regions, a moderately high mean dust concentration (6 µg/m3) in PM2.5 is also found in Dhaka (Bangladesh) along with a high average TEO level (6 µg/m3). High carcinogenic risk (>1 cancer case per 100000 adults) from airborne arsenic is observed in Dhaka (Bangladesh), Kanpur (India), and Hanoi (Vietnam). Industries of informal lead-acid battery and e-waste recycling as well as coal-fired brick kilns likely contribute to the elevated trace element concentrations found in Dhaka.

6.
Int J Pharm ; 652: 123853, 2024 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-38280500

RESUMEN

Respiratory infection caused by multi-drug resistant (MDR) Pseudomonas aeruginosa is challenging to treat. In this study, we investigate the optimal dose of anti-pseudomonas phage PEV31 (103, 105, and 108 PFU/mL) combined with ciprofloxacin (ranging from 1/8× MIC to 8× MIC) to treat the MDR P. aeruginosa strain FADD1-PA001 using time-kill studies. We determined the impact of phage growth kinetics in the presence of ciprofloxacin through one-step growth analysis. Single treatments with either phage PEV31 or ciprofloxacin (except at 8× MIC) showed limited bactericidal efficiency, with bacterial regrowth observed at 48 h. The most effective treatments were PEV31 at multiplicity of infection (MOI) of 0.1 and 100 combined with ciprofloxacin at concentrations above 1× MIC, resulting in a >4 log10 reduction in bacterial counts. While the burst size of phage PEV31 was decreased with increasing ciprofloxacin concentration, robust antimicrobial effects were still maintained in the combination treatment. Aerosol samples collected from vibrating mesh nebulization of the combination formulation at phage MOI of 100 with 2× MIC effectively inhibited bacterial density. In summary, our combination treatments eradicated in vitro bacterial growth and sustained antimicrobial effects for 48 h. These results indicated the potential application of nebulization-based strategies for the combination treatment against MDR lung infections.


Asunto(s)
Bacteriófagos , Infecciones por Pseudomonas , Humanos , Ciprofloxacina/farmacología , Infecciones por Pseudomonas/tratamiento farmacológico , Infecciones por Pseudomonas/microbiología , Aerosoles y Gotitas Respiratorias , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Terapia Respiratoria , Pseudomonas aeruginosa , Pruebas de Sensibilidad Microbiana
7.
Clin Nutr ; 43(1): 84-94, 2024 01.
Artículo en Inglés | MEDLINE | ID: mdl-38016243

RESUMEN

BACKGROUND: Sarcopenia is associated with poor outcomes in patients with cirrhosis. However, the prevalence of and associated factors for developing sarcopenia in this population remain to be determined. OBJECTIVES: This study aimed to summarize the prevalence, characteristics, and associated factors of sarcopenia in patients with cirrhosis. METHODS: Electronic searches were performed from inception to June 9, 2022 to identify the eligible studies. We meta-analyzed the prevalence of sarcopenia in overall patients with cirrhosis and subgroups. Both crude and adjusted odds ratios (ORs) were pooled using the random effects model. RESULTS: A total of 55 studies involving 13,158 patients from 17 countries were included. The overall prevalence of sarcopenia was 40.1 % (95 % CI 35.4%-44.9 %) in patients with cirrhosis. The pooled prevalence was higher in males, Child-Pugh class C cirrhosis, decompensated stage, ascites, subjective global assessment class C cirrhosis, and when sarcopenia was defined by L3-SMI (third lumbar-skeletal muscle index) at a higher cutoff. In multivariate analysis, older age (adjusted OR 1.04, 95 % CI 1.00-1.07), male (adjusted OR 4.75, 95 % CI 2.72-8.28), lower body mass index (BMI) (adjusted OR 0.78, 95 % CI 0.73-0.83), alcoholic liver disease (ALD) (adjusted OR 1.43, 95 % CI 1.19-1.72), but not ascites and hepatic encephalopathy, were significantly associated with an increased risk of sarcopenia in patients with cirrhosis. CONCLUSION: Sarcopenia is a prevalent complication, and older age, male patients, lower BMI, and patients with ALD are associated with an increased risk of sarcopenia in patients with cirrhosis.


Asunto(s)
Sarcopenia , Humanos , Masculino , Sarcopenia/etiología , Sarcopenia/complicaciones , Prevalencia , Cirrosis Hepática/complicaciones , Cirrosis Hepática/epidemiología , Músculo Esquelético , Fibrosis , Ascitis
8.
Int J Pharm ; 646: 123505, 2023 Nov 05.
Artículo en Inglés | MEDLINE | ID: mdl-37832702

RESUMEN

Bacteriophages or phages used as an alternative therapy for treating multi-drug resistant infections require formulation consideration. Current strategies to produce phage formulations involving organic solvents are based on empirical practices without a good understanding of phage stability during formulation development. In this study, we investigated the effect of common formulation organic solvents (ethanol, isopropyl alcohol, tetrahydrofuran (THF) and dimethyl sulfoxide (DMSO)) on the stability of Pseudomonas aeruginosa-specific myovirus (PEV1, PEV20) and podovirus (PEV31) phages using biological assay, transmission electron microscopy (TEM) and scattering near field optical microscopy (SNOM). The three phages were mixed with the solvents at different concentrations (25%, 50%, and 75% (v/v)) for 20 min. All phages were fully viable in the organic solvents at 25% (v/v) showing negligible titre changes. At the higher solvent concentration of 50% (v/v), the myoviruses PEV1 and PEV20 remained relatively stable (titre loss 0.4-1.3 log10), whereas the podovirus PEV31 became less stable (titre loss 0.25-3.8 log10), depending on the solvent used. Increasing the solvent level to 75% (v/v) caused increased morphological changes in TEM and decreased viability as indicated by the titre loss (0.32-7.4 log10), with DMSO being the most phage-destabilising solvent. SNOM spectra showed differences in the signal intensity and peak positions in the amide I and amide II regions, revealing altered phage proteins by the solvents. In conclusion, the choice of the solvents for phage formulation depends on both the phages and solvent types. Our results showed (1) the phages are more stable in the alcohols than DMSO and THF, and (2) the myoviruses tend to be more stable than the podovirus in the solvents. Overall, a low to moderate (25-50 % v/v) level of organic solvents (except 50% THF) can be used in formulation of the phages without a substantial titre loss.


Asunto(s)
Bacteriófagos , Podoviridae , Dimetilsulfóxido , Solventes , Amidas/farmacología , Pseudomonas aeruginosa
9.
Nat Geosci ; 16(9): 768-774, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37692903

RESUMEN

The Arctic warms nearly four times faster than the global average, and aerosols play an increasingly important role in Arctic climate change. In the Arctic, sea salt is a major aerosol component in terms of mass concentration during winter and spring. However, the mechanisms of sea salt aerosol production remain unclear. Sea salt aerosols are typically thought to be relatively large in size but low in number concentration, implying that their influence on cloud condensation nuclei population and cloud properties is generally minor. Here we present observational evidence of abundant sea salt aerosol production from blowing snow in the central Arctic. Blowing snow was observed more than 20% of the time from November to April. The sublimation of blowing snow generates high concentrations of fine-mode sea salt aerosol (diameter below 300 nm), enhancing cloud condensation nuclei concentrations up to tenfold above background levels. Using a global chemical transport model, we estimate that from November to April north of 70° N, sea salt aerosol produced from blowing snow accounts for about 27.6% of the total particle number, and the sea salt aerosol increases the longwave emissivity of clouds, leading to a calculated surface warming of +2.30 W m-2 under cloudy sky conditions.

10.
Clin Microbiol Infect ; 29(6): 702-709, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-36736661

RESUMEN

BACKGROUND: The increasing emergence of antimicrobial resistance worldwide has led to renewed interest in phage therapy. Unlike antibiotics, the lack of pharmacokinetics/pharmacodynamics (PK/PD) information represents a major challenge for phage therapy. As therapeutic phages are biological entities with the ability to self-replicate in the presence of susceptible bacteria, their PK/PD is far more complicated than that of antibiotics. OBJECTIVES: This narrative review examines the current literature on phage pharmacology and highlights major pharmacological challenges for phage therapy. SOURCES: Included articles were identified by searching PubMed and Google Scholar till June 2022. The search terms were 'bacteriophage', 'antimicrobial', 'pharmacokinetics' and 'pharmacodynamics'. Additional relevant references were obtained from articles retrieved from the primary search. CONTENT: In this review, phage PK is first discussed, focusing on absorption, distribution, metabolism, and elimination. Key factors affecting phage antimicrobial activities are reviewed, including multiplicity of infection, passive and active phage therapy, and the involvement of the human immune system. Importantly, we emphasize the impact of phage self-replication on the PK/PD and the fundamental phage characteristics that are required for PK/PD modelling and clinical translation. IMPLICATIONS: Recent progress in phage pharmacology has shown that we are in a far better position now to treat infections with phage therapy than a century ago. However, phage therapy is still in its infancy when compared to antibiotics due to the scarce pharmacological knowledge (e.g. PK/PD). Optimization of phage PK/PD is key for translation of phage therapy in patients.


Asunto(s)
Antiinfecciosos , Bacteriófagos , Terapia de Fagos , Humanos , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Antiinfecciosos/farmacología , Bacterias
11.
Int J Pharm ; 635: 122679, 2023 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-36738804

RESUMEN

Endolysins are bacteriophage-encoded enzymatic proteins that have great potential to treat multidrug-resistant bacterial infections. Bacteriophage endolysins Cpl-1 and ClyJ-3 have shown promising antimicrobial activity against Streptococcus pneumoniae, which causes pneumonia in humans. This is the first study to investigate the feasibility of spray-dried endolysins Cpl-1 and ClyJ-3 with excipients to produce inhalable powders. The two endolysins were individually tested with leucine and sugar (lactose or trehalose) for spray drying method followed by characterization of biological and physico-chemical properties. A complete loss of ClyJ-3 bioactivity was observed after atomization of the liquid feed solution(before the drying process), while Cpl-1 maintained its bioactivity in the spray-dried powders. Cpl-1 formulations containing leucine with lactose or trehalose showed promising physico-chemical properties (particle size, crystallinity, hygroscopicity, etc.) and aerosol performances (fine particle fraction values above 65%). The results indicated that endolysin Cpl-1 can be formulated as spray dried powders suitable for inhaled delivery to the lungs for the potential treatment of pulmonary infections.


Asunto(s)
Bacteriófagos , Neumonía , Humanos , Polvos/química , Química Farmacéutica/métodos , Lactosa/química , Bacteriófagos/química , Leucina/química , Trehalosa/química , Aerosoles y Gotitas Respiratorias , Tamaño de la Partícula , Administración por Inhalación
12.
Environ Sci Technol ; 57(1): 53-63, 2023 01 10.
Artículo en Inglés | MEDLINE | ID: mdl-36563184

RESUMEN

Atmospheric models of secondary organic aerosol (OA) (SOA) typically rely on parameters derived from environmental chambers. Chambers are subject to experimental artifacts, including losses of (1) particles to the walls (PWL), (2) vapors to the particles on the wall (V2PWL), and (3) vapors to the wall directly (VWL). We present a method for deriving artifact-corrected SOA parameters and translating these to volatility basis set (VBS) parameters for use in chemical transport models (CTMs). Our process involves combining a box model that accounts for chamber artifacts (Statistical Oxidation Model with a TwO-Moment Aerosol Sectional model (SOM-TOMAS)) with a pseudo-atmospheric simulation to develop VBS parameters that are fit across a range of OA mass concentrations. We found that VWL led to the highest percentage change in chamber SOA mass yields (high NOx: 36-680%; low NOx: 55-250%), followed by PWL (high NOx: 8-39%; low NOx: 10-37%), while the effects of V2PWL are negligible. In contrast to earlier work that assumed that V2PWL was a meaningful loss pathway, we show that V2PWL is an unimportant SOA loss pathway and can be ignored when analyzing chamber data. Using our updated VBS parameters, we found that not accounting for VWL may lead surface-level OA to be underestimated by 24% (0.25 µg m-3) as a global average or up to 130% (9.0 µg m-3) in regions of high biogenic or anthropogenic activity. Finally, we found that accurately accounting for PWL and VWL improves model-measurement agreement for fine mode aerosol mass concentrations (PM2.5) in the GEOS-Chem model.


Asunto(s)
Contaminantes Atmosféricos , Contaminantes Atmosféricos/análisis , Artefactos , Gases , Modelos Químicos , Aerosoles/análisis
13.
ACS Earth Space Chem ; 6(12): 2944-2954, 2022 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-36561195

RESUMEN

While sea spray particles are highly soluble by nature, and are thus excellent seeds for nascent cloud droplets, organic compounds such as surfactants have previously been identified within aerosol particles, bulk seawater, and the sea-surface microlayer in various oceans and seas. As the presence of dissolved surfactants within spray particles may limit their ability to act as cloud condensation nuclei (CCN), and since the abundance of CCN available during cloud formation is known to affect cloud albedo, the presence of surfactants in the marine environment can affect the local radiation balance. In this work, we added a model surfactant commonly used in households and industry (sodium dodecyl benzene sulfonate, SDBS) to a control solution of NaCl and observed its effects on the number of CCN produced by artificial breaking waves. We found that the addition of SDBS modified the number of CCN produced by a breaking wave analogue in three main ways: (I) by reducing the hygroscopicity of the resulting particulate; (II) by producing finer particulates than the control NaCl solution; and (III) by reducing the total number of particles produced overall. In addition, measurements of the absorption of ultraviolet light (λ = 224 nm) were used to quantify the concentration of SDBS in bulk water samples and aerosol extracts. We found that SDBS was significantly enriched in aerosol extracts relative to the bulk water even when the concentration of SDBS in the bulk water was below the limit of detection (LOD) of our quantitation methods. Thus, the surfactant studied will influence the production of CCN even when present in minute concentrations.

14.
BMC Med Inform Decis Mak ; 22(1): 339, 2022 12 22.
Artículo en Inglés | MEDLINE | ID: mdl-36550466

RESUMEN

BACKGROUND: Assessment and feedback is a common implementation strategy to improve healthcare provider fidelity to clinical guidelines. For immunization guidelines, fidelity is often measured with doses administered during eligible visits. Adding a patient refusal measure captures provider fidelity more completely (i.e., all instances of a provider recommending a vaccine, resulting in vaccination or refusal) and enables providers to track patient vaccine hesitancy patterns. However, many electronic health record (EHR) systems have no structured field to document multiple instances of refusals for specific vaccines, and existing billing codes for refusal are not vaccine specific. This study assessed the feasibility of a novel method for refusal documentation used in a study focused on human papillomavirus (HPV) vaccine. METHODS: An observational, descriptive-comparative, mixed-methods study design was used to conduct secondary data analysis from an implementation-effectiveness trial. The parent trial compared coach-based versus web-based practice facilitation, including assessment and feedback, to increase HPV vaccination in 21 community-based private pediatric practices. Providers were instructed to document initial HPV vaccine refusals in the EHR's immunization forms and subsequent refusals using dummy procedure codes, for use in assessment and feedback reports. This analysis examined adoption and maintenance of the refusal documentation method during eligible well visits, identified barriers and facilitators to documentation and described demographic patterns in patient refusals. RESULTS: Seven practices adopted the refusal documentation method. Among adopter practices, documented refusals started at 2.4% of eligible well visits at baseline, increased to 14.2% at the start of implementation, peaked at 24.0%, then declined to 18.8%. Barriers to refusal documentation included low prioritization, workflow integration and complication of the billing process. Facilitators included high motivation, documentation instructions and coach support. Among adopter practices, odds of refusing HPV vaccine were 25% higher for patients aged 15-17 years versus 11-12 years, and 18% lower for males versus females. CONCLUSIONS: We demonstrated the value of patient refusal documentation for measuring HPV vaccination guideline fidelity and ways that it can be improved in future research. Creation of vaccine-specific refusal billing codes or EHR adaptations to enable documenting multiple instances of specific vaccine refusals would facilitate consistent refusal documentation. Trial Registration NCT03399396 Registered in ClinicalTrials.gov on 1/16/2018.


Asunto(s)
Infecciones por Papillomavirus , Vacunas contra Papillomavirus , Masculino , Femenino , Humanos , Niño , Virus del Papiloma Humano , Infecciones por Papillomavirus/prevención & control , Estudios de Factibilidad , Vacunación , Inmunización
15.
Adv Drug Deliv Rev ; 191: 114561, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-36191861

RESUMEN

Dry powder inhalers (DPIs) can be used with a wide range of drugs such as small molecules and biologics and offer several advantages for inhaled therapy. Early DPI products were intended to treat asthma and lung chronic inflammatory disease by administering low-dose, high-potency drugs blended with lactose carrier particles. The use of lactose blends is still the most common approach to aid powder flowability and dose metering in DPI products. However, this conventional approach may not meet the high demand for formulation physical stability, aerosolisation performance, and bioavailability. To overcome these issues, innovative techniques coupled with modification of the traditional methods have been explored to engineer particles for enhanced drug delivery. Different particle engineering techniques have been utilised depending on the types of the active pharmaceutical ingredient (e.g., small molecules, peptides, proteins, cells) and the inhaled dose. This review discusses the challenges of formulating DPI formulations of low-dose and high-dose small molecule drugs, and biologics, followed by recent and emerging particle engineering strategies utilised in developing the right inhalable powder formulations for enhanced drug delivery.


Asunto(s)
Productos Biológicos , Lactosa , Humanos , Polvos/química , Administración por Inhalación , Lactosa/química , Química Farmacéutica , Inhaladores de Polvo Seco/métodos , Preparaciones Farmacéuticas/química , Tamaño de la Partícula , Aerosoles/química
16.
Pharm Res ; 39(12): 3047-3061, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36071354

RESUMEN

Dry powder inhalation formulations have become increasingly popular for local and systemic delivery of small molecules and biotherapeutics. Powder formulations provide distinct advantages over liquid formulations such as elimination of cold chain due to room temperature stability, improved portability, and the potential for increasing patient adherence. To become a viable product, it is essential to develop formulations that are stable (physically, chemically and/or biologically) and inhalable over the shelf-life. Physical particulate properties such as particle size, morphology and density, as well as chemical properties can significantly impact aerosol performance of the powder. This review will cover these critical attributes that can be engineered to enhance the dispersibility of inhalation powder formulations. Challenges in particle engineering for biotherapeutics will be assessed, followed by formulation strategies for overcoming the hurdles. Finally, the review will discuss recent examples of successful dry powder biotherapeutic formulations for inhalation delivery that have been clinically assessed.


Asunto(s)
Inhaladores de Polvo Seco , Humanos , Polvos/química , Administración por Inhalación , Aerosoles/química , Tamaño de la Partícula
17.
Environ Sci Technol ; 56(19): 13888-13899, 2022 Oct 04.
Artículo en Inglés | MEDLINE | ID: mdl-36112784

RESUMEN

Predictions of cloud droplet activation in the late summertime (September) central Arctic Ocean are made using κ-Köhler theory with novel observations of the aerosol chemical composition from a high-resolution time-of-flight chemical ionization mass spectrometer with a filter inlet for gases and aerosols (FIGAERO-CIMS) and an aerosol mass spectrometer (AMS), deployed during the Arctic Ocean 2018 expedition onboard the Swedish icebreaker Oden. We find that the hygroscopicity parameter κ of the total aerosol is 0.39 ± 0.19 (mean ± std). The predicted activation diameter of ∼25 to 130 nm particles is overestimated by 5%, leading to an underestimation of the cloud condensation nuclei (CCN) number concentration by 4-8%. From this, we conclude that the aerosol in the High Arctic late summer is acidic and therefore highly cloud active, with a substantial CCN contribution from Aitken mode particles. Variability in the predicted activation diameter is addressed mainly as a result of uncertainties in the aerosol size distribution measurements. The organic κ was on average 0.13, close to the commonly assumed κ of 0.1, and therefore did not significantly influence the predictions. These conclusions are supported by laboratory experiments of the activation potential of seven organic compounds selected as representative of the measured aerosol.

18.
Mar Pollut Bull ; 182: 113945, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35905703

RESUMEN

Rhodamine water tracer (RWT) released during the 2021 Tracer Release Experiment in the St. Lawrence Estuary provides a proxy for the water-soluble fractions of contaminant spills. Measurements of total and size-resolved aerosols were taken onboard a research vessel throughout the experiment. Size-resolved aerosol measurements show airborne transmission of water-soluble RWT in a bimodal distribution peaking at 5.2 µm and 0.9 µm. Highest aerosol RWT (30.5 pg m-3) was observed in the 12-hour daytime period following the first dye release (Sept. 5), while the lowest (8.8 pg m-3) was observed in the subsequent nighttime sample. Available wind and RWT patch information were used to identify factors contributing to the factor-of-three variation in aerosol RWT concentrations. Negligible correlations were found between aerosol RWT and wind speed and sample time-of-day. Wind direction is isolated as the key variable for consideration in identifying the impact of contaminant spills on coastal and inland communities.


Asunto(s)
Contaminantes Atmosféricos , Aerosoles/análisis , Contaminantes Atmosféricos/análisis , Monitoreo del Ambiente , Agua , Viento
19.
J Geophys Res Atmos ; 127(11): e2021JD036383, 2022 Jun 16.
Artículo en Inglés | MEDLINE | ID: mdl-35859907

RESUMEN

Detailed knowledge of the physical and chemical properties and sources of particles that form clouds is especially important in pristine areas like the Arctic, where particle concentrations are often low and observations are sparse. Here, we present in situ cloud and aerosol measurements from the central Arctic Ocean in August-September 2018 combined with air parcel source analysis. We provide direct experimental evidence that Aitken mode particles (particles with diameters ≲70 nm) significantly contribute to cloud condensation nuclei (CCN) or cloud droplet residuals, especially after the freeze-up of the sea ice in the transition toward fall. These Aitken mode particles were associated with air that spent more time over the pack ice, while size distributions dominated by accumulation mode particles (particles with diameters ≳70 nm) showed a stronger contribution of oceanic air and slightly different source regions. This was accompanied by changes in the average chemical composition of the accumulation mode aerosol with an increased relative contribution of organic material toward fall. Addition of aerosol mass due to aqueous-phase chemistry during in-cloud processing was probably small over the pack ice given the fact that we observed very similar particle size distributions in both the whole-air and cloud droplet residual data. These aerosol-cloud interaction observations provide valuable insight into the origin and physical and chemical properties of CCN over the pristine central Arctic Ocean.

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