PMC

Secondary sensitivity analyses for a) ozone and b) nitrogen dioxide exposures and risk of acute exacerbation, which show a consistent relationship with acute exacerbation across multiple cumulative exposure periods. HR: hazard ratio.

Ozone (O₃) and nitrogen dioxide (NO₂) exposure and risk of acute exacerbation. Mean levels, maximum levels and number of exceedances above standards for O₃ and NO₂ exposure over a 6-week period were associated with significantly increased risk for acute exacerbation of idiopathic pulmonary fibrosis. There was no association of particulate matter <10 µm in aerodynamic diameter (PM₁₀), carbon monoxide (CO) or sulfur dioxide (SO₂) exposure with acute exacerbation risk. There were no exceedances above CO or SO₂ standards. HR: hazard ratio.