Interagency Coordination to Manage Co-Occurring Intellectual and Developmental Disabilities and Mental Health Conditions.

OBJECTIVE: The authors aimed to identify barriers to and strategies for supporting coordination between state agencies for intellectual and developmental disability (IDD) or mental health to meet the mental health needs of people with co-occurring IDD and mental health conditions. METHODS: Forty-nine employees of state agencies as well as advocacy and service delivery organizations across 11 U.S. states with separate IDD and mental health agencies were interviewed between April 2022 and April 2023. Data were analyzed with a thematic analysis approach. RESULTS: Interviewees reported that relationships between the IDD and mental health agencies have elements of both competition and coordination and that coordination primarily takes place in response to crisis events. Barriers to interagency coordination included a narrow focus on the populations targeted by each agency, within-state variation in agency structures, and a lack of knowledge about co-occurring IDD and mental health conditions. Interviewees also described both administrative (e.g., memorandums of understanding) and agency culture (e.g., focusing on whole-person care) strategies that are or could be used to improve coordination to provide mental health services for people with both IDD and a mental health condition. CONCLUSIONS: Strategies that support state agencies in moving away from crisis response toward a focus on whole-person care should be prioritized to support coordination of mental health services for individuals with co-occurring IDD and mental health conditions.

Advances in the Separation and Detection of Secondary Organic Aerosol Produced by Decamethylcyclopentasiloxane (D5) in Laboratory-Generated and Ambient Aerosol.

Decamethylcyclopentasiloxane (D5), a common ingredient in many personal care products (PCPs), undergoes oxidation in the atmosphere, leading to the formation of secondary organic aerosol (SOA). Yet, the specific contributions of D5-derived SOA on ambient fine particulate matter (PM2.5) have not been characterized. This study addresses this knowledge gap by introducing a new analytical method to advance the molecular characterization of oxidized D5 and its detection in ambient aerosol. The newly developed reversed phase liquid chromatography method, in conjunction with high-resolution mass spectrometry, separates and detects D5 oxidation products, enabling new insights into their molecular and isomeric composition. Application of this method to laboratory-generated SOA and urban PM2.5 in New York City expands the number of D5 oxidation products observed in ambient aerosol and informs a list of molecular candidates to track D5-derived SOA in the atmosphere. An oxidation series was observed in which one or more methyl groups in D5 (C10H30O5Si5) is replaced by a hydroxyl group, which indicates the presence of multistep oxidation products in ambient PM2.5. Because of their specificity to PCPs and demonstrated detectability in ambient PM2.5, several oxidation products are proposed as molecular tracers for D5-derived SOA and may prove useful in assessing the impact of PCPs-derived SOA in the atmosphere.

Size-resolved aerosol at a Coastal Great Lakes Site: Impacts of new particle formation and lake spray.

The quantification of aerosol size distributions is crucial for understanding the climate and health impacts of aerosols, validating models, and identifying aerosol sources. This work provides one of the first continuous measurements of aerosol size distribution from 1.02 to 8671 nm near the shore of Lake Michigan. The data were collected during the Lake Michigan Ozone Study (LMOS 2017), a comprehensive air quality measurement campaign in May and June 2017. The time-resolved (2-min) size distribution are reported herein alongside meteorology, remotely sensed data, gravimetric filters, and gas-phase variables. Mean concentrations of key aerosol parameters include PM2.5 (6.4 µg m-3), number from 1 to 3 nm (1.80x104 cm-3) and number greater than 3 nm (8x103 cm-3). During the field campaign, approximately half of days showed daytime ultrafine burst events, characterized by particle growth from sub 10 nm to 25-100 nm. A specific investigation of ultrafine lake spray aerosol was conducted due to enhanced ultrafine particles in onshore flows coupled with sustained wave breaking conditions during the campaign. Upon closer examination, the relationships between the size distribution, wind direction, wind speed, and wave height did not qualitatively support ultrafine particle production from lake spray aerosol; statistical analysis of particle number and wind speed also failed to show a relationship. The alternative hypothesis of enhanced ultrafine particles in onshore flow originating mainly from new particle formation activity is supported by multiple lines of evidence.

Characterization of a novel mouse platelet transfusion model.

BACKGROUND AND OBJECTIVES: Platelet transfusions are increasing with medical advances. Based on FDA criteria, platelet units are assessed by in vitro measures; however, it is not known how platelet processing and storage duration affect function in vivo. Our study's aim was to develop a novel platelet transfusion model stored in mouse plasma that meets FDA criteria adapted to mice, and transfused fresh and stored platelets are detectable in clots in vivo. STUDY DESIGN AND METHODS: Platelet units stored in mouse plasma were prepared using a modified platelet-rich plasma (PRP) collection protocol. Characteristics of fresh and stored units, including pH, cell count, in vitro measures of activity, including activation and aggregation, and post-transfusion recovery (PTR), were determined. Lastly, a tail transection assay was conducted using mice transfused with fresh or stored units, and transfused platelets were identified by confocal imaging. RESULTS: Platelet units had acceptable platelet and white cell counts and were negative for bacterial contamination. Fresh and 1-day stored units had acceptable pH; the platelets were activatable by thrombin and adenosine diphosphate, agreeable with thrombin, had acceptable PTR, and were present in vivo in clots of recipients after tail transection. In contrast, 2-day stored units had clinically unacceptable quality. CONCLUSION: We developed mouse platelets for transfusion analogous to human platelet units using a modified PRP collection protocol with maximum storage of 1 day for an 'old' unit. This provides a powerful tool to test how process modifications and storage conditions affect transfused platelet function in vivo.

De-escalation of the Agitated Pediatric Patient: A Standardized Patient Case for Pediatric Residents.

Introduction: Over the past 5 years, pediatric mental health emergencies requiring emergency safety evaluations and inpatient boarding of pediatric patients requiring psychiatric admission have increased. Pediatric trainees must learn to effectively and safely de-escalate a patient with agitated or aggressive behavior, as mental health patients take up a larger proportion of their patient population. This standardized patient case addresses gaps in knowledge and skills to ameliorate the care of children and adolescents with behavioral crises in the hospital. Methods: Resident learners were presented with a teenage patient admitted to the hospital and awaiting inpatient psychiatric placement for suicidal ideation who became acutely agitated with aggressive behaviors. Learners were expected to attempt to verbally de-escalate the patient and select an appropriate pharmacologic agent for decreasing agitation in the patient. A standardized debrief was conducted with the assistance of child and adolescent mental health experts. Results: Twenty-two learners participated in this activity. Residents' confidence in their management skills of the acutely agitated pediatric patient significantly increased after completion of the activity. Seventy-three percent of learners felt confident or very confident in their de-escalation skills at the end of the case, and 86% agreed that the case improved their confidence in managing acute agitation scenarios on the inpatient wards. Discussion: This case led to overall increased self-efficacy in caring for the acutely agitated pediatric patient. Future iterations may include multidisciplinary learners of various skill levels and evaluating changes in patient-centered outcomes, such as restraint use, after implementation of the case.

Documentation of Trauma-Informed Care Elements for Young People Hospitalized After Assault Trauma.

INTRODUCTION: Violent traumatic injury, including firearm violence, can adversely impact individual and community health. Trauma-informed care (TIC) can promote resilience and prevent future violence in patients who have experienced trauma. However, few protocols exist to facilitate implementation of TIC for patients who survive traumatic injury. The purpose of the study is to characterize documentation of TIC practices and identify opportunities for intervention in a single academic quaternary care center. METHODS: This study is a retrospective chart review analyzing the documentation of trauma-informed elements in the electronic medical record of a random sample of youth patients (ages 12-23) admitted for assault trauma to the pediatric (n = 50) and adult trauma (n = 200) services between 2016 and mid-2021. Descriptive statistics were used to summarize patient demographics, hospitalization characteristics, and documentation of trauma-informed elements. Chi-square analyses were performed to compare pediatric and adult trauma services. RESULTS: Among pediatric and adult assault trauma patients, 36.0% and 80.5% were hospitalized for firearm injury, respectively. More patients admitted to the pediatric trauma service (96%) had at least one trauma-informed element documented than patients admitted to the adult service (82.5%). Social workers were the most likely clinicians to document a trauma-informed element. Pain assessment and social support were most frequently documented. Safety assessments for suicidal ideation, retaliatory violence, and access to a firearm were rarely documented. CONCLUSIONS: Results highlight opportunities to develop trauma-informed interventions for youth admitted for assault trauma. Standardized TIC documentation could be used to assess risk of violent reinjury and mitigate sequelae of trauma.

Experiences of health care services among people with cognitive disabilities and mental health conditions.

BACKGROUND: People with cognitive disabilities such as intellectual and developmental disabilities face significant barriers to accessing high-quality health care services. Barriers may be exacerbated for those with co-occurring mental health conditions. OBJECTIVE: This study compares patient experiences of health care services between adults with and without cognitive disabilities and, among people with a cognitive disability, those with and without co-occurring mental health conditions. METHODS: Cross-sectional analyses were conducted using 2021 Medical Expenditure Panel Survey data, a national U.S. survey, to examine differences in Consumer Assessment of Healthcare Providers and Systems measures. RESULTS: Adults with cognitive disabilities reported lower satisfaction with health care services compared to the general population (7.62 (95% confidence interval (CI): 7.41-7.83) vs. 8.33 (95% CI: 8.29-8.38) on scale from 0 to 10). Adults with cognitive disabilities were less likely to report that providers listened carefully to them (odds ratio (OR): 0.55, 95% CI: 0.42-0.71), explained things in a way that was easy to understand (OR: 0.48, 95% CI: 0.35-0.66), showed respect for what they had to say (OR: 0.38, 95% CI: 0.29-0.51), spent enough time with them (OR: 0.52, 95% CI: 0.40-0.69), or gave advice that was easy to understand (OR: 0.40, 95% CI: 0.28-0.58) compared to the general population. Among adults with cognitive disabilities, there were no differences based on co-occurring mental health conditions. CONCLUSIONS: Adults with cognitive disabilities report lower satisfaction with health care services driven by worse experiences with the health care system. Policies to increase provider capacity to support this population should be prioritized.

Development of Spatio-Temporal Land Use Regression Models for Fine Particulate Matter and Wood-Burning Tracers in Temuco, Chile.

Biomass burning is common in much of the world, and in some areas, residential wood-burning has increased. However, air pollution resulting from biomass burning is an important public health problem. A sampling campaign was carried out between May 2017 and July 2018 in over 64 sites in four sessions, to develop a spatio-temporal land use regression (LUR) model for fine particulate matter (PM) and wood-burning tracers levoglucosan and soluble potassium (Ksol) in a city heavily impacted by wood-burning. The mean (sd) was 46.5 (37.4) µg m-3 for PM2.5, 0.607 (0.538) µg m-3 for levoglucosan, and 0.635 (0.489) µg m-3 for Ksol. LUR models for PM2.5, levoglucosan, and Ksol had a satisfactory performance (LOSOCV R2), explaining 88.8%, 87.4%, and 87.3% of the total variance, respectively. All models included sociodemographic predictors consistent with the pattern of use of wood-burning in homes. The models were applied to predict concentrations surfaces and to estimate exposures for an epidemiological study.

Characterization of a Novel Mouse Platelet Transfusion Model.

BACKGROUND: Platelet transfusions are increasing with advances in medical care. Based on FDA criteria, platelet units are assessed by in vitro measures; however, it is not known how platelet processing and storage duration affect function in vivo. To address this, we developed a novel platelet transfusion model that meets FDA criteria adapted to mice, and transfused fresh and stored platelets are detected in clots in vivo. STUDY DESIGN AND METHODS: Platelet units stored in mouse plasma were prepared using a modified platelet rich plasma collection protocol. Characteristics of fresh and stored units, including pH, cell count, in vitro measures of activity, including activation and aggregation, and post-transfusion recovery (PTR), were determined. Lastly, a tail transection assay was conducted using mice transfused with fresh or stored units, and transfused platelets were identified by confocal imaging. RESULTS: Platelet units had acceptable platelet and white cell counts and were negative for bacterial contamination. Fresh and 1-day stored units had acceptable pH; the platelets were activatable by thrombin and ADP, aggregable with thrombin, had acceptable PTR, and were present in vivo in clots of recipients after tail transection. In contrast, 2-day stored units had clinically unacceptable quality. DISCUSSION: We developed mouse platelets for transfusion analogous to human platelet units using a modified platelet rich plasma collection protocol with maximum storage of 1 day for an "old" unit. This provides a powerful tool to test how process modifications and storage conditions affect transfused platelet function in vivo.

Association of cannabis use with patient-reported pain measures among adults with chronic pain in US states with medical cannabis programs.

INTRODUCTION: Most Americans live in a state that has legalized cannabis as a medical treatment for pain, but it is unclear how chronic pain intensity relates to cannabis use. Our objective was to examine the association between patient-reported pain measures and cannabis among adults with chronic pain. METHODS: This cross-sectional study of a representative sample of adults reporting chronic non-cancer pain in 36 states and DC with active medical cannabis programs from March to April 2022 assessed cannabis use for chronic pain, categorized as active (within 30 days), past (>31 days), or never use (referent). Measures were pain intensity (primary) and interference, Widespread Pain Index, and number of chronic pain diagnoses. RESULTS: Among 1628 participants (57% female, 69% white), 352 (22%) actively used cannabis to treat chronic pain, 137 (8%) reported past cannabis use, and 1139 (70%) never used cannabis. In adjusted models, active cannabis use was associated with higher scores for pain intensity (score difference 1.03, 95% CI 0.05 to 2.02) and pain interference (score difference 1.82, 95% CI 0.99 to 2.65) compared with never use. Persons who actively used cannabis had higher Widespread Pain Index scores (score difference 0.56, 95% CI 0.26 to 0.86) and more chronic pain diagnoses (difference 0.45, 95% CI 0.06 to 0.83). CONCLUSION: People with chronic non-cancer pain who used cannabis for pain reported non-clinically meaningful worse pain measures and greater burden of chronic pain conditions than their counterparts who never used cannabis. Alternatively, those with worse pain and greater burden of pain appear more likely to use cannabis.

Low-Dose Dietary Fish Oil Improves RBC Deformability without Improving Post-Transfusion Recovery in Mice.

Long-chain polyunsaturated fatty acids (LC-PUFAs) are important modulators of red blood cell (RBC) rheology. Dietary LC-PUFAs are readily incorporated into the RBC membrane, improving RBC deformability, fluidity, and hydration. Female C57BL/6J mice consumed diets containing increasing amounts of fish oil (FO) ad libitum for 8 weeks. RBC deformability, filterability, and post-transfusion recovery (PTR) were evaluated before and after cold storage. Lipidomics and lipid peroxidation markers were evaluated in fresh and stored RBCs. High-dose dietary FO (50%, 100%) was associated with a reduction in RBC quality (i.e., in vivo lifespan, deformability, lipid peroxidation) along with a reduced 24 h PTR after cold storage. Low-dose dietary FO (6.25-12.5%) improved the filterability of fresh RBCs and reduced the lipid peroxidation of cold-stored RBCs. Although low doses of FO improved RBC deformability and reduced oxidative stress, no improvement was observed for the PTR of stored RBCs. The improvement in RBC deformability observed with low-dose FO supplementation could potentially benefit endurance athletes and patients with conditions resulting from reduced perfusion, such as peripheral vascular disease.

Identifying Optimal Methods for Addressing Confounding Bias When Estimating the Effects of State-level Policies.

BACKGROUND: Policy evaluation studies that assess how state-level policies affect health-related outcomes are foundational to health and social policy research. The relative ability of newer analytic methods to address confounding, a key source of bias in observational studies, has not been closely examined. METHODS: We conducted a simulation study to examine how differing magnitudes of confounding affected the performance of 4 methods used for policy evaluations: (1) the two-way fixed effects difference-in-differences model; (2) a 1-period lagged autoregressive model; (3) augmented synthetic control method; and (4) the doubly robust difference-in-differences approach with multiple time periods from Callaway-Sant'Anna. We simulated our data to have staggered policy adoption and multiple confounding scenarios (i.e., varying the magnitude and nature of confounding relationships). RESULTS: Bias increased for each method: (1) as confounding magnitude increases; (2) when confounding is generated with respect to prior outcome trends (rather than levels), and (3) when confounding associations are nonlinear (rather than linear). The autoregressive model and augmented synthetic control method had notably lower root mean squared error than the two-way fixed effects and Callaway-Sant'Anna approaches for all scenarios; the exception is nonlinear confounding by prior trends, where Callaway-Sant'Anna excels. Coverage rates were unreasonably high for the augmented synthetic control method (e.g., 100%), reflecting large model-based standard errors and wide confidence intervals in practice. CONCLUSIONS: In our simulation study, no single method consistently outperformed the others, but a researcher's toolkit should include all methodologic options. Our simulations and associated R package can help researchers choose the most appropriate approach for their data.

On the Ability of the N-O Bond to Support a Stable Stereogenic Axis: Peptide-Catalyzed Atroposelective N-Oxidation.

During studies of atroposelective, peptide-catalyzed N-oxidations of pyridines, we observed lower-than-expected barriers to atropisomerization for these stereodynamic processes under the reaction conditions. Mechanistic studies indicate a hydrogen bond-assisted racemization mechanism intrinsic to both the starting materials and products. We also identified a protonation-dependent barrier to rotation that operates for the starting materials alone. Nonetheless, several substrates were amenable to atroposelective N-oxidations via kinetic resolution, yielding krel values of up to 12.6 and the isolation of one N-oxide with >99:1 er after recrystallization.

Companion animal veterinarians discuss aspects of one health with pet owners during most veterinary appointments.

OBJECTIVE: To examine the prevalence and context of one-health conversations between veterinarians and clients in companion animal practice. SAMPLE: A random selection of 60 companion animal veterinarians; a convenience sample of 917 interactions from Southern Ontario, Canada. Of these, 100 audio-video-recorded interactions including 47 of 60 veterinarians were randomly selected for inclusion in this study. METHODS: Audio-video recordings were made of veterinarian-client-patient interactions between November 2017 and January 2019. A researcher-generated coding framework was developed and used to assess the prevalence and content of one-health topics communicated during veterinary appointments. RESULTS: Of the interactions assessed, 60 were preventive care and 40 were health problem appointments. Further, 78% (78/100) included at least 1 discussion related to one health. One-health topics included zoonoses (28% [28/100]), animal behavior (25% [25/100]), illness/disease (20% [20/100]), activity level/exercise (16% [16/100]), nutrition (16% [16/100]), dentistry (6% [6/100]), body weight (3% [3/100]), animal welfare (3% [3/100]), dog/cat bites (2% [2/100]), cannabis (2% [2/100]), and aging (1% [1/100]). Zoonotic diseases were mentioned in 65 appointments, 28 of which evolved into a one-health discussion. Antibiotics were discussed in 27 appointments, none of which were discussed in relation to one health (eg, antimicrobial resistance). CLINICAL RELEVANCE: Findings suggest that one-health topics are raised within most veterinary appointments. Opportunities exist for more comprehensive one-health conversations between veterinarians and their clients, particularly in relation to zoonotic diseases and antimicrobials.

Experiential Learning of Childhood Growth and Development Through a Pediatric Play Project.

ABSTRACT: The adoption of a new undergraduate nursing curriculum granted the opportunity to develop a new method for teaching growth and development. The Pediatric Play Project was designed as part of clinical experience where students explored principles of growth and development by designing a toy or play activity for a hospitalized pediatric patient. Students exhibited immense creativity while meeting learning outcomes, and the project received positive feedback from students and faculty. With minor refinement of the project, students will continue to gain understanding of the nurse's role in promoting growth and development for the hospitalized child.

Changes in Visual Long-Term Potentiation Show Preserved Cyclicity in Human Females Taking Combined Oral Contraceptives.

INTRODUCTION: The combined oral contraceptive (COC) pill is often employed to address physical and neurological symptoms in menstrual cycle-related disorders by suppressing shifts in endogenous gonadal hormone fluctuations. Symptom persistence, especially in the lead up to the hormone-free interval (HFI), suggests an underlying neurobiological mechanism of preserved cycling. Our study utilised a non-invasive method of visually inducing long-term potentiation (LTP) to index changes in neural plasticity in the absence of hormonal fluctuations. METHODS: Visually induced LTP was recorded using electroencephalography in 24 healthy female COC users across three sessions: days 3 and 21 during active hormone pills, and day 24 during the HFI. The Daily Record of the Severity of Problems (DRSP) questionnaire tracked premenstrual symptoms. Dynamic causal modelling (DCM) was used to elucidate the neural connectivity and receptor activity changes associated with LTP across different days of COC. RESULTS: Visually induced LTP was greater on day 21 than day 3 (p = 0.011) and was localised to the P2 visually evoked potential. There was no effect of the HFI (day 24) on LTP. DCM of differences between days 3 and 21 showed changes to inhibitory interneuronal gating of LTP in cortical layer VI. The DRSP only showed a significant increase in symptoms in the HFI, meaning the LTP result appeared more sensitive to cyclicity. CONCLUSIONS: This study provides objective evidence of preserved cyclicity in COC users through enhanced LTP on day 21 compared to day 3 of a 28-day COC regimen, indicating that relatively higher excitation in the brain despite peripheral gonadal suppression may underlie and exacerbate menstrual cycle-related disorders.

A deep neural network framework to derive interpretable decision rules for accurate traumatic brain injury identification of infants.

OBJECTIVE: We aimed to develop a robust framework to model the complex association between clinical features and traumatic brain injury (TBI) risk in children under age two, and identify significant features to derive clinical decision rules for triage decisions. METHODS: In this retrospective study, four frequently used machine learning models, i.e., support vector machine (SVM), random forest (RF), deep neural network (DNN), and XGBoost (XGB), were compared to identify significant clinical features from 24 input features associated with the TBI risk in children under age two under the permutation feature importance test (PermFIT) framework by using the publicly available data set from the Pediatric Emergency Care Applied Research Network (PECARN) study. The prediction accuracy was determined by comparing the predicted TBI status with the computed tomography (CT) scan results since CT scan is the gold standard for diagnosing TBI. RESULTS: At a significance level of [Formula: see text], DNN, RF, XGB, and SVM identified 9, 1, 2,  and 4 significant features, respectively. In a comparison of accuracy (Accuracy), the area under the curve (AUC), and the precision-recall area under the curve (PR-AUC), the permutation feature importance test for DNN model was the most powerful framework for identifying significant features and outperformed other methods, i.e., RF, XGB, and SVM, with Accuracy, AUC, and PR-AUC as 0.915, 0.794, and 0.974, respectively. CONCLUSION: These results indicate that the PermFIT-DNN framework robustly identifies significant clinical features associated with TBI status and improves prediction performance. The findings could be used to inform the development of clinical decision tools designed to inform triage decisions.

Transfusion medicine approaches for spontaneous intracerebral hemorrhage patients.

PURPOSE OF REVIEW: Spontaneous intracerebral hemorrhage (ICH) is the deadliest stroke subtype. Acute treatments necessitate rapid hemorrhage control to minimize secondary brain injury. Here, we discuss the overlap of transfusion medicine and acute ICH care relating to diagnostic testing and therapies relevant for coagulopathy reversal and secondary brain injury prevention. RECENT FINDINGS: Hematoma expansion (HE) is the largest contributor to poor outcomes after ICH. Conventional coagulation assays to diagnose coagulopathy after ICH does not predict HE. Given the testing limitations, empiric pragmatic hemorrhage control therapies have been trialed but have not improved ICH outcomes, with some therapies even causing harm. It is still unknown whether faster administration of these therapies will improve outcomes. Alternative coagulation tests (e.g., viscoelastic hemostatic assays, amongst others) may identify coagulopathies relevant for HE, currently not diagnosed using conventional assays. This provides opportunities for rapid, targeted therapies. In parallel, ongoing work is investigating alternative treatments using transfusion-based or transfusion-sparing pharmacotherapies that can be implemented in hemorrhage control strategies after ICH. SUMMARY: Further work is needed to identify improved laboratory diagnostic approaches and transfusion medicine treatment strategies to prevent HE and optimize hemorrhage control in ICH patients, who appear particularly vulnerable to the impacts of transfusion medicine practices.

Use of Cannabis and Other Pain Treatments Among Adults With Chronic Pain in US States With Medical Cannabis Programs.

This cross-sectional study uses a survey to estimate use of cannabis and other pain treatments among adults with chronic pain in areas with medical cannabis programs in 36 US states and Washington, DC.

Submicron Aerosol Composition and Source Contribution across the Kathmandu Valley, Nepal, in Winter.

The Kathmandu valley experiences an average wintertime PM1 concentration of ∼100 µg m-3 and daily peaks over 200 µg m-3. We present ambient nonrefractory PM1 chemical composition, and concentration measured by a mini aerosol mass spectrometer (mAMS) sequentially at Dhulikhel (on the valley exterior), then urban Ratnapark, and finally suburban Lalitpur in winter 2018. At all sites, organic aerosol (OA) was the largest contributor to combined PM1 (C-PM1) (49%) and black carbon (BC) was the second largest contributor (21%). The average background C-PM1 at Dhulikhel was 48 µg m-3; the urban enhancement was 120% (58 µg m-3). BC had an average of 6.1 µg m-3 at Dhulikhel, an urban enhancement of 17.4 µg m-3. Sulfate (SO4) was 3.6 µg m-3 at Dhulikhel, then 7.5 µg m-3 at Ratnapark, and 12.0 µg m-3 at Lalitpur in the brick kiln region. Chloride (Chl) increased by 330 and 250% from Dhulikhel to Ratnapark and Lalitpur on average. Positive matrix factorization (PMF) identified seven OA sources, four primary OA sources, hydrocarbon-like (HOA), biomass burning (BBOA), trash burning (TBOA), a sulfate-containing local OA source (sLOA), and three secondary oxygenated organic aerosols (OOA). OOA was the largest fraction of OA, over 50% outside the valley and 36% within. HOA (traffic) was the most prominent primary source, contributing 21% of all OA and 44% of BC. Brick kilns were the second largest contributor to C-PM1, 12% of OA, 33% of BC, and a primary emitter of aerosol sulfate. These results, though successive, indicate the importance of multisite measurements to understand ambient particulate matter concentration heterogeneity across urban regions.