Lung function measures, and other characteristics of the diary panel sub-cohort, by zone and year (n = 380)a.

aEach subject contributed up to 63 days of data in the diary panel.bParticipants in overlapping area of increased exposure zone and stack zone: diary panel cohort (2006 = 6(4); 2007 = 5(2); 2008 = 5(3)) contributed data to both zones.cParticipants with spirometry and eNO.dbd-bronchodilator.eGeometric mean and SD.fParticipants with PEF/symptom diary.gPEF recorded three times twice daily at morning and evening. Highest of three measurements used for each session.