BACKGROUND: Particulate matter may be toxic to human tissue. Ambient air particulate matter < or =10micrometer in aerodynamic size (PM10), which changes under different environmental conditions, is a complex mixture of organic and inorganic compounds. The Asian dust event caused by meteorological phenomena can also spread unique particulate matter in affected areas. We evaluated production of ROS, TGF-beta, fibronectin, and NF kappa B by exposing normal epithelial cells to Asian dust particulate matter. METHODS: Bronchial epithelial cells were exposed to 0, 50, 100microgramg/ml of a suspension of PM10 for 24 h. ROS were detected by measurement of DCF release from DCF-DA by FACScan. TGF-beta, fibronectin, and NF kappa B were detected by western blotting. RESULTS: PM10 exposure increased the expression of TGF-beta, fibronectin, and NF kappa B. ROS production and TGF-betalevels were significantly higher with 50 or 100microgram/ml PM10. Fibronectin and NF kappa B production were significantly higher after 100microgram/ml of PM10. CONCLUSION: PM10 from Asian dust particles might have fibrotic potential in bronchial epithelial cells via ROS induction after PM10 exposure.