Air pollution threatens the respiratory health of patients with interstitial lung disease (ILD). High-efficiency air purifiers, featuring easy operation and excellent particulate matter removal efficiency, have been shown in previous studies to potentially delay lung function deterioration and reduce acute exacerbation risk in respiratory disease patients. This randomized crossover study employs air purifiers to filter indoor gaseous pollutants, allergens, and other contaminants, aiming to alleviate respiratory irritation, improve daily life comfort, and enhance overall health status in ILD patients.