Exposure to ambient particulate matter (PM) 2.5 can impair alveolar macrophages (AMs) functions and induce pathological conditions. This study explores the impact of PM2.5 exposure on AMs, focusing on gene expression changes and functional alterations. Murine AMs cell line MH-S were exposed to PM2.5 at a concentration of 100 µg/ml for durations of 3 and 48 hours. After 3 hours of exposure, genes involved in inflammatory and immune responses were activated, including TNF and B-cell receptor signaling pathways. In contrast, 48 hours of exposure significantly altered genes related to cell proliferation, apoptosis, and immune processes, with PI3K-Akt and cytokine-cytokine receptor interaction pathways. PM2.5 initially triggers immune responses; however, prolonged exposure over 48 hours impairs AM functions risk of chronic inflammation and cancer. This research provides foundational data for therapeutic approaches related to PM2.5 exposure.