The range from 11 to 15 years of age was
targeted because it covers the overlapping age
period of pulmonary-function testing across cohorts.
Follow-up over this age range was conducted
from 1994 through 1998 in cohort C,
from 1997 through 2001 in cohort D, and from
2007 through 2011 in cohort E. The estimated
health effect of each pollutant is reported as the
expected difference in lung-function growth associated
with a difference in exposure equal to
the median of the changes in pollution in the
five communities over the course of the study
period (Table 1)