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Effects of ambient ozone on
lung function in children over a two-summer period
M.V. Kopp*, W. Bohnet*, T.
Frischer#, C. Ulmer*, M. Studnicka+, G. Ihorst*, C. Gardner*,,
J. Forster*, R. Urbanek#, J. Kuehr*
ABSTRACT: There is a general
consensus that short term exposure to ozone (O3) causes a
decrease in lung function parameters such as forced vital
capacity (FVC) and forced expiratory volume in one second
(FEV1). The objective of this study was to assess the
reproducibility of lung function decrements after ambient O3
exposure over a two-summer period.
The authors studied 797 children with a mean age of 8.2 yrs (95%
confidence interval: 6.9-9.5) from the second and third grades
of ten elementary schools in Austria and southwestern Germany.
At the outset the various study locations were stratified into
three groups with low (L), medium (M) and high (H) O3 exposure
(range of mean O3 concentration in the locations April-October
1994: 24-30 (L); 33-38 (M); 44-52 (H) parts per billion (ppb)).
Four lung function tests were performed on each child between
March 1994 and November 1995.
The increases in FVC and FEV1 recorded from one test period to
the next were expressed as mL
-
day-1. A significantly lower
FVC and FEV1 increase was observed in children exposed to high
ambient O3 concentration during the summer season. (FVC in
summer 1994: 0.83 (L); 0.56 (M); 0.55 (H) mL
-
day-1; p=0.004; and summer
1995: 0.80 (L); 0.63 (M); 0.56 (H) mL
-
day-1; p=0.011; FEV1 in summer
1994: 0.48 (L); 0.34 (M); 0.18 (H) mL
-
day-1; p=0.004 and summer 1995:
0.68 (L); 0.45 (M); 0.41 (H) mL
-
day-1, p=0.006). There was no
significant difference in FVC or FEV1 increase between the
groups during the winter period. Adjusting for sex, age,
height and passive smoke exposure, linear regression revealed
a statistically significant negative association of average
ambient O3 concentration with the FVC and FEV1 increase in
both summers. During the winter period no association of O3
with FVC or FEV1 was observed.
In conclusion, in two consecutive
summer periods the authors found reproducible lung function
decrements in children exposed to high levels of ambient ozone.
Reoccurrence of ozone associated lung function deficits might
increase the likelihood of persisting effects on the childrens'
airways.
*University Childrens Hospital, Freiburg
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