Background: Air pollution, especially PM2.5, is one of the most concerning problems around the world, leading to health problems. There are few studies on acute upper respiratory tract infection (URTI), especially in adults.

Objective: To investigate the association between PM2.5 and acute URTI.

Materials and Methods: Retrospective data analyses of patients between 2017 and 2019 who visited the outpatient department in Maharaj Nakorn Chiang Mai Hospital with acute URTI was performed. The authors also collected the daily data of PM2.5, PM10, O₃, NO₂, temperature, and humidity from the center of Chiang Mai Province. The Pearson correlation method was used to identify correlations between acute URTI and those variables.

Results: The data of 104,711 patients with acute URTI were collected. Acute nasopharyngitis, acute pharyngitis, and acute tonsillitis were the three most common diseases. The highest level of PM2.5 each year was in January to February. The results were also the same for PM10, O₃, and NO₂. The present study revealed that PM2.5 had a significant correlation with number of acute respiratory infection patients, r=0.17 (p<0.001), which meant higher level of PM2.5 was associated with higher number of patients. The results were also the same for PM10, O₃, and NO₂. For temperature and humidity, the results were the opposite correlations, which meant the higher the temperature and humidity, the fewer patients were observed that day. The present study also found the regression question, which was every 1 point higher of PM2.5, there would be 19% more patients that day.

Conclusion: There was a relationship between pollution, especially PM2.5 and acute URTI. The higher level of PM2.5 is related to an increased number of URTI patients. It is the same results for PM10, O₃, and NO₂.

Keywords: Fine particulate matter; PM2.5; Acute upper respiratory tract infections

DOI: 10.35755/jmedassocthai.2024.2.13948

Received 1 October 2023 | Revised 16 January 2024 | Accepted 24 January 2024