Investigating the Transport Correlation of Ozone and PM2.5 between Haikou and Guangdong-Guangxi Cities
Haikou, a representative tropical city in China, experiences air pollution influenced by both local emissions and regional transport. This study analyzed O3 and PM2.5 concentrations, emission sources, and meteorological fields from Haikou and Guangdong-Guangxi cities in 2024, employing correlation analysis and the Weighted Potential Source Contribution Function (WPSCF) to systematically investigate spatial-temporal patterns, regional linkages, and transport mechanisms. Results revealed distinct pollution characteristics: Hainan exhibited prominent O3 pollution in autumn and winter, while the Pearl River Delta (PRD) in Guangdong suffered significant O3 pollution year-round, positioning it as the core control area. Guangxi was characterized by severe PM2.5 pollution in winter with extensive high concentration areas. Haikou's O3 and PM2.5 concentrations showed strong correlations with those in Zhanjiang and Maoming throughout the year, particularly in winter. Regional transport analysis indicated that O3 pollution in Haikou depended on stable cross-regional precursor transport coupled with intense photochemical conditions, whereas PM2.5 exhibited diverse transport pathways across seasons. Lag effect analysis confirmed that pollution exceedance days were substantially influenced by upwind transport from the previous day, highlighting the dominant role of cross-regional physical transport. Autumn pollution was driven by stable surface northeasterly winds and upper-level uniform pressure fields. Potential source areas were highly consistent with the MEIC emission inventory, confirming distinct contributions of transport pathways for O3 and PM2.5. These findings provide a scientific basis for differentiated collaborative control of air pollution in tropical coastal cities.