16. SPATIAL-TEMPORAL VARIATION AND RELATIONSHIP OF PM₂.₅ AND PM₁₀ IN THE NORTHERN KEY ECONOMIC REGION OF VIETNAM

Tóm tắt

This study aimed to investigate the spatial-temporal variation and interaction of ambient PM₂.₅ and PM₁₀ in the Northern Key Economic Region of Vietnam, specifically in Hai Phong, Hung Yen, and Quang Ninh provinces. In July and October 2025, two 24-hour sample campaigns were held at traffic, residential, and background sites. PM₁₀ and PM_2.5 were collected during two campaigns in 2025 following the US EPA gravimetric reference methods (40 CFR Part 50, Appendix L and J). For PM₂.₅, the average concentrations were between 15.6 and 59.2 µg/m³, and for PM₁₀, they were between 26.7 and 105.9 µg/m³. Both of these values were higher than the WHO (2021) 24-hour limit. The concentrations consistently followed the order traffic > residential > background. The PM₂.₅/PM₁₀ ratio (0.52 - 0.71) showed that fine particles from combustion and traffic were the most common, and a significant connection (r = 0.9, p < 2.2e - 16) showed that the emissions came from the same places. These findings reveal persistent particulate pollution across northern Vietnam and emphasize the combined influence of anthropogenic activities and meteorological conditions. The study provides essential evidence for developing targeted air quality management and emission control policies under monsoonal climate conditions in Southeast Asia.