Introduction: Exposure to outdoor fine particulate matter (PM2.5), is a driver of disease progression in patients with idiopathic pulmonary fibrosis (IPF). The impact of indoor air pollution on patients with IPF remains unknown.
Objectives: To evaluate patterns of exposure to indoor PM2.5 in patients with progressive IPF, and the impact of PM2.5 reduction on disease progression and symptom burden.
Materials and Methods: 10 patients with progressive IPF were recruited. Spirometry and the St. George’s respiratory questionnaire (SGRQ) were completed in the home at day 0 and after 4 weeks. PM2.5 concentrations were measured for 2 weeks prior to, and 2 weeks following installation of a high efficiency air purifier. The impact of change in mean PM2.5 exposure on forced vital capacity (FVC) and SGRQ scores was evaluated using linear mixed models.
Results: All participants utilized the air purifier consistently, with 9/10 reporting satisfaction with the device. Exposure to indoor PM2.5 was relatively low prior to device installation, with a median daily PM2.5 concentration of 3.7µg/m3 (IQR 3.1-8.1)µg/m3 . Despite this, air-purifier use lead to a significant decrease in PM2.5 concentrations for all but one participant, with a median decrease of –2.63µg/m3 (IQR (-9.33 to 4.61).
No statistically significant relationship between change in PM2.5 and rate of FVC decline was identified (-0.37% decrease in rate of FVC decline per 5µg/m3 reduction in FVC (CI: -5.88 to 5.41%). A median decrease in SGRQ score of -3.4 (IQR -4.6 to -0.36) was seen after installation of the air purifier (Figure 1). No statistically significant relationship between change in PM2.5 and change in. SGRQ scores was identified.
Conclusions: While an association between reductions in PM2.5 and rates of FVC decline was not identified, air purifier use significantly decreased indoor PM2.5 exposure and was widely accepted. More work is needed to understand the longitudinal impacts of indoor PM2.5 in patients with ILD.