Health Impacts of PM2.5 Across Age Groups in Thailand: An Integrated Analysis of Respiratory and Cardiovascular Outcomes and Healthcare Utilization

Background: Fine particulate matter (PM2.5) remains a major environmental health concern in Thailand, yet its health burden is often examined separately within specific age groups or clinical outcomes. This study integrated evidence from adolescent and older-adult populations with healthcare utilization data to characterize the health impacts of PM2.5 across different stages of life in Bangkok and surrounding areas. Methods: An integrated multi-source analysis was conducted using three complementary datasets: a cross-sectional study of 215 adolescents aged 10-18 years in Bangkok; a two-month observational study of 120 adults aged >=55 years conducted during January-February 2025; and healthcare utilization data covering January-February 2025 from Bangkok and neighboring provinces. Respiratory symptoms, cardiovascular symptoms, outdoor exposure, mask use, and healthcare utilization were examined. Age-stratified outpatient and inpatient patterns were also evaluated. Results: Among adolescents, 27.9% reported severe respiratory symptoms, while 33.5% had low awareness of PM2.5-related health risks. In older adults, PM2.5 levels showed a strong positive correlation with respiratory and cardiovascular symptoms (r = 0.87, p < 0.01). Shortness of breath (70.8%), persistent cough (60.0%), and chest tightness (54.2%) were common, while elevated blood pressure (41.7%) and palpitations (31.7%) indicated cardiovascular involvement. Consistent mask use was associated with a 25-35% lower prevalence of symptoms, whereas high outdoor exposure was associated with nearly twice the symptom rate. Healthcare data further demonstrated increasing medical demand during elevated PM2.5 exposure; each 10 ug/m3 increase in PM2.5 was associated with 258.1 additional outpatient visits and 13.8 additional inpatient admissions in the previously analyzed healthcare dataset. Older adults represented the greatest healthcare burden, with those aged >=60 years accounting for the largest proportion of inpatient utilization. Conclusion: The integrated findings demonstrate that PM2.5-related health effects extend across age groups but manifest differently across the life course, ranging from respiratory symptoms among adolescents to combined respiratory and cardiovascular effects and greater healthcare utilization among older adults. Protective behaviors, particularly consistent mask use and reduced outdoor exposure, may mitigate these effects. These findings support age-responsive air-quality interventions, exposure-reduction strategies, and healthcare preparedness during periods of elevated PM2.5 in Thailand.