A new study published in the Journal of American Medical Association shows that sulfate, ammonium, and nitrate elements of Particulate matter 2.5 (PM2.5) were linked to the most damage and were associated with baseline severity, illness progression, and death among patients with fibrotic interstitial lung diseases (fILDs), underscoring the need for reductions in pollution from human sources.

Particulate matter with a diameter of 2.5 m or less is linked to poor outcomes for people with idiopathic pulmonary fibrosis, but its links to other fibrotic interstitial lung conditions and the composition of PM2.5 are yet unknown. As a result, Gillian Goobie and colleagues carried out this study to look at the relationship between fILD patients’ exposure to PM2.5 and their mortality and lung function.

Patients in this worldwide multicenter, prospective cohort research were enrolled in the Simmons Center for Interstitial Lung Disease Registry at the University of Pittsburgh in Pittsburgh; 42 sites of the Pulmonary Fibrosis Foundation Registry; and 8 sites of the Canadian Registry for Pulmonary Fibrosis. A total of 6683 individuals with fILD were enrolled in the study. The data was examined from June 1, 2021 to August 2, 2022. PM2.5 and constituent exposure was calculated using hybrid models that used satellite-derived aerosol optical depth, chemical transport models, and ground-based PM2.5 observations.

The key findings of this study were:

1. The median follow-up across the three groups was 2.9 years, with 28% of patients dying and 10% undergoing lung transplantation.

2. The cohort included 3653 men, 205 Black people, and 5609 White people.

3. The median age at enrolment was 66 years across all cohorts.

4. A hazard ratio for death of 4.40 was found in the Simmons cohort, 1.71 in the Pulmonary Fibrosis Foundation cohort, and 1.45 in the Canadian Registry for Pulmonary Fibrosis cohort.

5. Higher exposure to sulfate, nitrate, and ammonium PM2.5 components was related with higher mortality across all cohorts, and multi-constituent models revealed that these constituents were associated with the most unfavorable mortality outcomes.

6. Meta-analyses indicated consistent relationships between sulfate and ammonium exposure and mortality, as well as the rate of decline in forced vital capacity and carbon monoxide diffusion capacity, and a link between rising levels of PM2.5 multi-constituent mixture and all outcomes.

Air Pollution with particulate matter about 2.5 micron increases lung damage: JAMA