The effects of semi-annual and 3.5 yr mean ozone (O 3 ) concentrations on children9s forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were assessed over a study period of 3.5 yrs in 2,153 schoolchildren from 15 study sites in South Western Germany and Lower Austria.Spirometric parameters were assessed twice a year, and differences between consecutive measurements divided by days were considered as a measure of lung growth. Exposure was analysed in four classes, separately for winter and summer (semiannual mean O 3 concentrations 22-30, 30-38, 38-46, 46-54 parts per billion (ppb) in summer and 4-12, 12-20, 20-28, 28-36 ppb in winter).Regression methods for repeated measurements were used, and these revealed a significantly lower FVC (FEV1) increase estimated at -19.2 (-18.5) mL?100 days -1 for semi-annual mean O 3 exposure in summer between 46 and 54 ppb compared to exposure between 22 and 30 ppb. However, in winter, the estimated difference in FVC (FEV1) was 16.4 (10.9) mL?100 days -1 between the semi-annual O 3 class 28-36 ppb and the 4-12 ppb class. By means of linear regression the study found that there was no association between growth rates and mean summer O 3 for FVC and FEV1 over a 3.5 yr period.The authors conclude that medium-term effects on schoolchildren9s lung growth are possibly present, but are in the long-term not detectable for forced vital capacity and forced expiratory volume in one second over a 3.5 yr period due to partial reversibility.

There is a general consensus that short term exposure to ozone (O 3 ) 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 O 3 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) 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 O 3 concentration with the FVC and FEV1 increase in both summers. During the winter period no association of O 3 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. Eur Respir J 2000; 16: 893±900. Laboratory studies of volunteers exposed to high ozone (O 3 ) concentrations in chambers and in epidemiological field studies both have revealed an O 3 related decline in lung function parameters such as forced vital capacity (FVC), forced expiratory volume in one second (FEV1) and peak expiratory flow (PEF) [1±4]. Since children spend more time outdoors and are physically more active than adults and as the growing lung might be more susceptible, they are regarded as a potential risk population for O 3 induced health effects.The authors recently published data from a follow-up study with school-aged children living in two small cities in southwestern Germany [5]. A negative association between O 3 exposure under natural living conditions and lung function (FVC, FEV1) In contrast to the short-term health effects of ozone, there are few studies that have investigated the possible long term health effects of ozone in humans due to problems with exposure assessment and the coincident effects of other pollutants. Reduced levels of FVC and FEV1 after prolonged ozone exposure were reported in both children and adults [15,16]. However, the crosssectional design of these studies does not allow for an investigation into the cause-effect relationship, because outcome as well as exposure is assessed at the same time.Repeated lung-function testing was therefore performed over two years in ten communities with differing levels of Eur Respir J 2000; 16: 893±900 Printed in UK ± all rights reserved

In order to investigate nasal inflammation and subsequent adaptation after ambient ozone exposure, nasal lavage (NL) fluid was collected from 170 schoolchildren on 11 occasions (time points) between March and October.Eosinophil cationic protein (ECP), albumin and leukocytes were quantified as markers of nasal inflammation. The highest half-hour outdoor O 3 concentration for each individual on the day prior to the NL was used as a measure of exposure (O 3 indiv). To avoid confounding with exposure to common environmental allergens, the study population was restricted to children without sensitization to inhalant allergens.In the initial period of increased O 3 levels in May (time point 4), with a median O 3 indiv of 135 mg . m -3 (5th ±95th percentile 100±184 mg . m ). Cross-sectional analysis of all 11 time points revealed no significant association of O 3 indiv on the one hand and ECP, albumin and leukocyte levels on the other. A multivariable model estimated using generalized estimating equations showed a statistically significant association of O 3 indiv and leukocytes and ECP as the dependent variable, when time points 1±4 were analysed (p<0.05). In the same model, this association diminished continuously when time points 5±11 were added stepwise, in spite of high O 3 exposure. Not even a tendency towards an O 3 effect could be recognized when time points 1±8 were considered.The results indicate: 1) acute inflammation of the nasal mucosa after the first increase in ambient ozone levels, with 2) a significant dose-dependent increase in leukocyte and eosinophil cationic protein levels, and 3) possible adaptation of the nasal mucosa in spite of constant high levels of ozone exposure in children during the summer season.

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