400,000 people breathed the dust and smoke at Ground Zero after the World Trade Center attacks. Friedman et al identified 180 people (mostly residents) who had persistent respiratory symptoms after 9/11. (All were never-smokers.) They were matched with 473 controls who were symptom-free.
More cases had abnormal spirometry (19% vs 11%), although most were normal. Measures of airway resistance were frequently abnormal using impulse oscillometry (often used in kids, as active participation is not necessary): 68% vs. 27% had elevated airway resistance, and 36% vs. 7% had frequency dependence of resistance. Most of those with normal spirometry had the abnormal resistance patterns. (Oscillometry has been used to identify disease in coal workers with normal PFTs in the past.) Authors postulate that distal airway damage could be responsible.
Friedman SM et al. Case–Control Study of Lung Function in World Trade Center Health Registry Area Residents and Workers. Am J Resp Crit Care Med 2011;184:582-589.