Abstract
Air pollution poses severe health risks, particularly for children and vulnerable populations. This study investigates ambient particulate matter (PM) pollution, analyzes hazardous air pollutants, develops an air quality database, and implements risk communication strategies to enhance public awareness in 2024. Low-cost sensors were deployed to measure Fine Particulate Matter (PM2.5) and Coarse Particulate Matter (PM10) levels in schools, hospitals, and monitoring stations operated by the Pollution Control Department (PCD). The highest PM levels were recorded between January and April in 2024, with some locations exceeding 300 μg/m³—posing critical health risks, particularly in schools and hospitals near the Laos border. After April 2024, PM concentrations significantly declined. Notably, air pollution levels in Laos were higher than in Thailand, likely due to biomass burning and industrial emissions. PM2.5 samples collected from three schools revealed elevated pollution levels from March to May 2024, with daily concentrations exceeding 100 μg/m³ on certain days. Chemical analysis identified a strong correlation between PM2.5 levels and Polycyclic Aromatic Hydrocarbons (PAHs). Schools with the highest PAH and Carcinogenic PAHs (cPAH) concentrations exhibited increased potential health risks. During smoke haze season (SH), Oxidative Potential (OP) was strongly correlated with PM2.5, particularly in schools with high PM2.5 levels, such as Ban Namliang School. In contrast, OP levels were lower during the non-smoke haze season (NSH). The Hazard Quotient (HQ) for children aged 6-12 years was higher than the safety threshold in several schools during SH season, particularly in Ban Namliang School. However, during NSH season, HQ levels approached the safety threshold but still posed a risk due to air pollution. The analysis of PM2.5 composition using Scanning Electron Microscopy with Energy Dispersive X-ray Spectroscopy (SEM-EDS) revealed that the sources of PM2.5 vary by location, linked to local activities and geographical features. Additionally, urinary biomonitoring of 1-hydroxypyrene (1-OHP) in students indicated higher exposure levels in areas affected by air pollution, particularly near coal-fired power plants. However, no statistically significant differences were observed between SH and NSH seasons, suggesting persistent exposure sources throughout the year. The direction and origin of air masses vary by season. During the haze season, air masses from the west and northwest carry pollution from open burning in northern Thailand, Myanmar, and northern Laos, leading to elevated PM2.5 levels. In the non-haze season, air masses shift to come from the southeast, east, and south (primarily passing through Laos), causing air pollutants in the study area to originate mainly from Laos. Lichen bioindicators were assessed to evaluate air quality, revealing that pollution-sensitive species were prevalent in high-altitude areas with cleaner air, whereas pollution-tolerant species dominated urban environments, reflecting spatial variations in air pollution levels. Risk communication initiatives, including citizen science programs and science fairs, played a crucial role in increasing public awareness. However, further efforts should expand outreach to diverse demographic groups and leverage digital platforms for broader engagement. Key recommendations from this study include continuous air quality monitoring, stringent pollution source mitigation, integration of advanced monitoring technologies and bioindicators, and strengthened cross-border collaboration to ensure sustainable air quality management.
