Northern Thailand experiences annual haze events with fine particulate matter (PM2.5) exceeding standards, posing risks to schoolchildren. This cross-sectional study (Chiang Mai, 2024) evaluated respiratory impacts among primary school children aged 8–12 years. Daily mean PM2.5 concentrations were obtained from a single fixed-site monitoring station (36T) located within 2 km of the spirometry site. Among 93 children with acceptable spirometry, 52% exhibited restrictive, 18% obstructive, and 30% had normal function. After adjustment for BMI, males had significantly lower odds of any pulmonary abnormality than females (AOR = 0.084; 95% CI 0.017–0.417; p = 0.002). The mean FEV₁/FVC ratio was normal (86.30 ± 13.07%), whereas mean FVC, FEV₁, and PEF were significantly below predicted values, indicating a predominantly restrictive pattern. This predominance likely reflects cumulative exposure to biomass-burning related PM2.5 during the haze season, infiltration of outdoor PM2.5 into indoor environments alongside indoor sources, and the vulnerability of developing lungs in children’s factors that reduce lung volumes while largely preserving the FEV₁/FVC ratio. The exposure assessment provides pragmatic, proximity-based estimates but is limited by reliance on one station and one season, which may not capture spatial or temporal variability. These findings highlight sex-based susceptibility and support stronger air quality protections for children.

Exposure to fine particulate matter (PM_2.5) is linked to metabolic dysfunction, yet evidence on its impact on hormonal regulation remains limited. This study examined seasonal changes in insulin, adiponectin, leptin, and HOMA-IR levels among healthy individuals and those with metabolic syndrome (MS) in Chiang Mai, Thailand. Fifty participants (25 healthy, 25 with MS) were assessed during high (February–April)- and low (May–July)-PM_2.5 seasons. Insulin levels increased in healthy individuals (mean: 9.3 to 14.9 µIU/mL; p = 0.051) and decreased in participants with MS (22.0 to 13.7 µIU/mL; p = 0.214), with a significant interaction effect (p = 0.020). Leptin increased significantly in both groups, but more markedly in the MS group (p < 0.001), also with a significant interaction (p < 0.001). HOMA-IR rose significantly in healthy individuals (p = 0.036) but not in participants with MS. Adiponectin remained stable across groups and seasons. At baseline, the MS group had significantly higher rates of diabetes (p = 0.050), hypertension (p = 0.001), and hyperlipidemia (p = 0.049). These findings suggest that PM_2.5 may influence metabolic and hormonal profiles, particularly in individuals with existing metabolic disorders.

Antioxidant intake from natural sources may enhance defense systems against oxidative stress induced by environmental factors such as cigarette smoke. Watercress (Nasturtium officinale) is an abundant source of antioxidants. This study aimed to determine the antioxidant effects of watercress consumption in people exposed to cigarette smoke in Chiang Mai, Thailand. Forty-five participants (15 non-smokers, 15 non-smokers with self-reported exposure to secondhand smoke (SHS), and 15 smokers) aged 20–60 years consumed 60 g of fresh watercress with three meals daily for seven days. Clinical characteristics, lipid profiles, total antioxidant capacity, and oxidative stress markers were evaluated before and after the intervention. After 7 days of watercress consumption, body mass index (BMI) and hip circumference significantly decreased among non-smokers. Watercress consumption reduced total cholesterol and low-density lipoprotein cholesterol (LDL-C) levels in smokers and in SHS-exposed non-smokers; however, high-density lipoprotein cholesterol (HDL-C) significantly decreased in SHS-exposed non-smokers. Catalase activity increased, and malondialdehyde levels decreased in all groups. One of the measures of plasma total antioxidant capacity significantly improved in non-smokers. These findings suggest that watercress consumption may improve lipid profiles and mitigate oxidative stress, and that these beneficial effects differ across people with different levels of exposure to cigarette smoke. However, further studies are suggested to clarify these results.

Watercress (Nasturtium officinale R.Br.) is a cruciferous vegetable rich in bioactive compounds that may improve cardiovascular disease (CVD) risk factors. However, clinical evidence regarding its direct impact on CVD risk remains limited. This study evaluated the efficacy of watercress consumption on cardiovascular parameters, oxidative stress biomarkers, and estimated CVD risk in middle-aged Thai adults with low-to-moderate risk. Twenty-five participants completed the randomized, placebo-controlled pilot study. The watercress group (n = 12) consumed 16 dried watercress capsules daily for four weeks, while the placebo group (n = 13) received a placebo. Physical examinations, arterial stiffness, lipid profiles, and biochemical biomarkers were analyzed at baseline and the end of treatment. The 10-year CVD risk was estimated using the Framingham equation. Following the intervention, the watercress group showed significant reductions in both systolic and diastolic blood pressure compared to the placebo group. Within the watercress group, significant improvements from baseline to post-intervention were observed in oxidized LDL, antioxidant capacity (ABTS), and estimated 10-year CVD risk score. However, these three parameters did not reach statistical significance when compared to the placebo group. In conclusion, daily watercress consumption significantly lowers blood pressure and demonstrates a potential dietary option for supporting cardiovascular health. Nevertheless, larger and longer-term clinical trials remain necessary.

Ambient fine particulate matter (PM_2.5) is associated with oxidative stress, metabolic dysregulation, and cardiometabolic disease. However, systemic metabolic responses to contrasting real-world ambient air pollution exposure environments remain poorly characterized. In this cross-sectional study, untargeted proton nuclear magnetic resonance (¹H-NMR)-based urinary metabolomics was used to investigate metabolic signatures associated with contrasting ambient air pollution exposure environments in Thailand. Adults residing in Chiang Mai (high-exposure region; n = 51) and Songkhla (low-exposure region; n = 52) were recruited during a period of elevated regional air pollution, with long-term residence serving as a proxy for differential exposure to ambient air pollution environments. Partial least squares-discriminant analysis (PLS-DA) demonstrated separation between exposure groups (R² = 0.873, Q² = 0.447), indicating good model fit but only modest predictive ability. Eight urinary metabolites differed significantly (p < 0.05), implicating pathways related to tryptophan metabolism, nucleotide metabolism, energy metabolism, and host–microbial co-metabolism. L-arginine and L-cystathionine showed lower relative abundance in the high-exposure group, and six metabolites remained significant after Benjamini–Hochberg false discovery rate correction. Following covariate adjustment, L-tryptophan, hippuric acid, xanthine, and 5-hydroxyindoleacetic acid (5-HIAA) remained significantly associated with the high-exposure group. Contrasting ambient air pollution exposure environments, indexed by regional PM_2.5 concentrations, were associated with coordinated urinary metabolic alterations. Because long-term regional residence served as a proxy for individual-level exposure and diet and lifestyle differences between regions were not fully controlled, these findings should be interpreted as associations with contrasting regional exposure environments. Metabolite annotations remain putative and require validation in longitudinal studies with comprehensive pollutant characterization and individual-level exposure assessment.

Chiang Mai, Thailand, experiences seasonal fine particulate matter (PM_2.5) pollution associated with metabolic diseases, but the underlying mechanisms remain unclear. This prospective observational study compared plasma metabolomes of 25 healthy adults in Samoeng District, a highly affected area, between low and high PM_2.5 exposure seasons using proton nuclear magnetic resonance (¹H-NMR) spectroscopy. Twenty-six metabolites differentiating haze and non-haze seasons were identified using PLS-DA (VIP > 1.5). During the haze season, 11 were elevated, whereas 15 were decreased. Among the elevated metabolites, the top five—maleylacetoacetic acid, deoxyribose 5-phosphate, betaine, 3-hydroxyanthranilic acid, and 1-methyladenosine—were associated with inflammation, increased reactive oxygen species, nitric oxide inhibition, and altered amino acid metabolism. The top five decreased metabolites—deoxyguanosine, D-arabitol, glycerophosphocholine, ophthalmic acid, and oxaloacetic acid—were involved in several metabolic pathways, particularly those involved in energy metabolism. A total of 56 metabolic pathways were altered by high PM_2.5 exposure, including pathways related to amino acids, lipids, sugars, nucleotides, vitamins, and energy metabolism. High PM_2.5 exposure disrupts metabolites and pathways, inducing inflammation, oxidative stress, impaired lipid/energy metabolism, insulin resistance, and high blood pressure. These alterations may increase the risk of metabolic and cardiovascular diseases, with dysregulated metabolites serving as potential biomarkers. These findings highlight the molecular impact of air pollution in affected populations and may support preventive strategies and public health policy development in affected regions. Further studies are needed to clarify these findings.