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.

Inclusion Criteria:

• Patients diagnosed with interstitial lung disease (ILD).
• Stable disease status, defined as no hospitalization due to acute exacerbation within the past month.

Exclusion Criteria:

• Patients with complications of severe organ failure (including heart, liver, or kidney failure), malignant tumors, or mental disorders.
• A history of respiratory tract infection within the past two weeks.

1. The informed consent form signed by study participants does not include clauses authorizing the sharing of de-identified individual participant data (IPD) with external researchers. In accordance with the ethical approval requirements, no secondary use of IPD beyond the primary study objectives is permitted without explicit participant consent.
2. The sample size of this study is relatively small, and the collected IPD has high heterogeneity due to individual differences in patient clinical characteristics and intervention responsiveness. Sharing such a limited dataset may not support robust secondary research findings, and could lead to misleading interpretations of the intervention effect on pulmonary inflammation.