This scoping review examines the distribution, sources, and characterization of atmospheric microplastics (AMPs) in Southeast Asia (SEA), following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) guidelines. A comprehensive search of Scopus and PubMed identified 58 relevant articles, with 16 meeting the inclusion criteria. Findings indicate high microplastic (MP) concentrations in urban centres, notably in Malaysia, Indonesia, and Thailand, a pattern driven by rapid urbanisation, industrial emissions, textile production, and insufficient waste management. Predominant polymer types include polyethylene (PE), polypropylene (PP), and polyester (PET), with fibres and black particles being the most common forms. Black particles, often linked to tire wear and vehicular emissions, underscore traffic pollution’s role in AMP distribution, while PET fibres reflect the influence of SEA’s textile industry. Geographic gaps were observed, with limited studies in countries such as Cambodia and Laos. The review highlights the need for standardised sampling and quantification methods to ensure data comparability and calls for expanded research into rural and coastal regions. Future studies should prioritise longitudinal investigations into the effects of chronic exposure on health; this is particularly relevant for nanoplastics (NPs) because of their greater potential for biological penetration. These insights form a crucial foundation for mitigating AMP pollution in SEA.

Introduction Environmental tobacco smoke (ETS) is generally known as secondhand smoke. Assessing the magnitude of children’s exposure to ETS from early infancy is essential for public health and research endeavours. Urinary cotinine is now widely recognised as the primary indicator for assessing exposure to ETS across all age groups. This systematic review and meta-analysis aim to synthesise all the published evidence on the urinary cotinine cut-off concentrations used to categorise children under 5 years as being exposed to ETS. Methods and analysis We will conduct a systematic review according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses. A comprehensive search will be conducted from various databases including PubMed, EMBASE, Scopus and Cochrane Library. This search will be performed from the earliest published articles up to the latest available studies until February 2025. We will include all the experimental and observational studies, such as cohort, case–control and cross-sectional, that measure urinary cotinine concentrations in children under 5 years old. Data extraction will be conducted using a standardised data extraction form, and the study quality will be evaluated according to the guidelines specified by the Newcastle-Ottawa Scale. The extracted data will be pooled and combined for meta-analysis. Two reviewers will independently screen, select and assess the quality of the included study. The result will be tabulated in a table of characteristics of the included study, which consists of the cut-off cotinine concentrations, analytical technique, method referred, study design, study area and respondents’ characteristics. Ethics and dissemination Ethics approval is not required as this is a review of collected published data. Findings will be disseminated in peer-reviewed publications and conference presentations, as well as with key stakeholders, health policymakers and healthcare professionals. PROSPERO registration number CRD42024556969.

Climate-related hazards are occurring with increasing frequency, resulting in notable disruptions to healthcare systems. In Malaysia, healthcare facilities are particularly impacted by flooding and heatwaves, which can occur annually across some regions. Despite these recurrent challenges, there remains limited availability of a standardized tool to systematically assess healthcare facility (HCF) vulnerability to climate hazards. This study aimed to develop, validate and conduct a field testing of the Vulnerability Index Tool for Assessing Levels of Climate Resilience in Healthcare Facilities (VITAL-HCF) for facility-level assessment in Malaysia. The VITAL-HCF was developed through extensive literature review, experts consultations, and adaptation of the World Health Organization (WHO) healthcare facility vulnerability checklist. The tool underwent forward and backward translation to ensure linguistic and contextual equivalence, followed by content and face validation by subject-matter experts in climate and healthcare professionals. Subsequently, field testing was performed in three government healthcare facilities to assess the clarity, applicability, and feasibility of administration to ensure accurate responses representing facility-level capacity and vulnerability. The healthcare facility vulnerability index (HCFVI) for heatwaves and flooding was then calculated for each facility. Revised Scale-Level Content Validity Indices (S-CVI/Ave) varied across the exposure, sensitivity and adaptive capacity domains (0.93–1.00). Items with a content validity index < 0.83 were either removed or revised and reorganized to improve relevance. Face validation showed good clarity with S-FVI/Ave ≥ 0.87. The final tool comprised 12 exposure, 11 sensitivity, and 181 adaptive capacity indicators. Field testing showed that a facilitated, multidisciplinary group approach among key respondents was feasible and timely. Facility A, located in an urban setting, had high vulnerability for hot weather and heatwaves (HCFVI = 0.51), while facilities B and C recorded moderate vulnerability. Both Facilities A and B recorded moderate vulnerability for floods, while Facility C, a hospital in an urban setting, had low vulnerability (HCFVI = 0.23). The VITAL-HCF demonstrated satisfactory content validity, face validity, and feasibility for assessing climate-related vulnerability in HCFs. The tool incorporates key vulnerability components of exposure, sensitivity, and adaptive capacity, providing a structured approach for the systematic assessment of climate-related vulnerability in healthcare facilities to support targeted preparedness and resilience planning.

Background: Environmental tobacco smoke (ETS) exposure is a preventable risk factor for adverse health outcomes in early childhood. Urinary cotinine is widely used as a non-invasive biomarker of ETS exposure; however, variation in reported cut-off concentrations limits comparability across studies. No prior systematic review has quantitatively synthesised urinary cotinine cut-off values for children under five years. This review aimed to systematically summarise and evaluate these cut-off concentrations in early childhood. Methods: A systematic review and meta-analysis were conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020) guidelines and a prospectively published protocol (PROSPERO CRD42024556969). PubMed, Embase, Scopus, and the Cochrane Library were searched from inception to February 2025. Observational and experimental studies reporting urinary cotinine cut-off concentrations to classify ETS exposure among children under five years were included. Study quality was assessed using the Newcastle–Ottawa Scale. Random-effects meta-analyses were performed to estimate pooled urinary cotinine cut-off concentrations for ETS exposure classification, stratified by unit of measurement (ng/mL vs ng/mg creatinine). Results: Twelve studies were included. Reported urinary cotinine cut-off concentrations ranged from 0.05 to 30 ng/mL for unadjusted values and from 2.47 to 120 ng/mg creatinine for creatinine-adjusted values. Meta-analysis yielded pooled reference values of 5.90 ng/mL (95% CI: 5.53–6.27) and 50.36 ng/mg creatinine (95% CI: 47.53–53.20), respectively. Conclusion: Urinary cotinine is a valid biomarker for assessing ETS in young children, but inconsistent cut-off values limit comparability. The pooled estimates may aid interpretation in surveillance and research but should not be used as universal thresholds. Standardized, age-appropriate cut-offs are needed to strengthen exposure assessment and inform child-focused tobacco control policies.