Correlation between PM2.5 Concentration and the Incidence of Respiratory Diseases in Outpatients at Satun Hospital, Satun Province 2019

Abstract

     This survey research by retrospective study examined the correlation between daily concentrations of fine particulate matter (PM_2.5) and outpatient visits for respiratory diseases at Satun Hospital, Satun Province, Thailand, in 2019. Data were obtained from the Pollution Control Department’s air quality monitoring station, the Satun meteorological station, and hospital outpatient data, including 1,869 cases of chronic obstructive pulmonary disease (COPD), asthma, and rhinitis.

     In 2019, Satun recorded 10 days exceeding the national daily PM_2.5 standard (37.5 µg/m³) and 22 days exceeding the WHO guideline (25 µg/m³). The highest daily concentration (69 µg/m³) occurred during August–September, corresponding with transboundary haze episodes. Among outpatients, COPD accounted for the largest share (1,005 cases), followed by rhinitis (620) and asthma (244). Pearson’s correlation analysis revealed positive associations between PM_2.5 concentrations and outpatient visits for asthma (r = 0.260, p < 0.001) and rhinitis (r = 0.209, p < 0.001), particularly among children (≤12 years) without smoking behavior. In contrast, COPD showed a negative correlation, especially among elderly male patients (≥60 years) without smoking behavior (r = -0.243, p < 0.001). The findings highlight that PM_2.5 exposure significantly contributes to the burden of respiratory diseases in Satun, especially in vulnerable groups such as children and non-smokers. Meanwhile, the negative correlation with COPD suggests complex or delayed health responses.