The Impact of Bushfire Smoke Exposure on Airway Epithelium and Protective Cilia

Climate change has intensified the frequency and severity of bushfires and wildfires, which continually pose serious public health risks through smoke inhalation. The airway is normally protected by several mechanisms, including motile cilia, which are critical for mucociliary clearance (MCC) to remove inhaled hazardous substances from the lungs. The impact of bushfire smoke on cilia function remains understudied. Here, we exposed cultured primary nasal airway epithelial cells from healthy individuals to bushfire smoke and assessed ciliary function and cell integrity. As little as 5 min of exposure significantly reduced cilia beating frequency, with complete immotility and structural damage to the epithelial cells observed after 30 min. Notably, cells protected by level-2 surgical masks maintained normal ciliary function. Our findings highlight the vulnerability of the airway epithelium to short-term smoke exposure, as well as the protective potential of face coverings.