CHARACTERIZING AEROSOL PARTICULATE MATTER IN BIEN HOA CITY, DONG NAI PROVINCE: MASS CONCENTRATION LEVELS, RATIOS, AND LONG-RANGE TRANSPORT BY HYSPLIT MODEL

Bien Hoa City, Dong Nai province, is showing signs of increasing pollution. In this study, aerosol particulate matter - PM samples (including TSP, PM10, PM2.5) were collected uniformly (same time, same location, same 24-hour period) on specialized sampling paper using high volume air samplers (HVAS, Tisch Environment, Inc.) for the first time. PM samples were quantified using a Mettler Toledo XS205 weight scale and source apportionment was traced using the backward trajectory analysis model HYSPLIT. The results showed that the mass concentrations of TSP, PM10, PM2.5 during the dry season (2023) were 97.4 ± 11.4 µg/m³, 64.4 ± 7.9 µg/m³, 49.89 ± 7.2 µg/m³ respectively; and during the wet season (2023) were 71.5 ± 10.3 µg/m³, 51.4 ± 8.7 µg/m³, 36.8 ± 7.5 µg/m³ respectively. The concentrations of PM10 and PM2.5 exceeded the recommended values of the World Health Organization (WHO), especially PM2.5 which exceeded both the WHO guidelines and the national limit of QCVN 05:2023/BTNMT. The distribution of fine particulate matter PM₂.₅ shows a significant dominance in the overall particulate composition, accounting for approximately 52-78% depending on the season. The HYSPLIT backward trajectory analysis suggests that distant sources may influence air quality in the study area; however, this observation requires further verification due to the limited sample size.