Ozone pollution and ozone biomonitoring in European cities. Part I. Ozone concentrations and cumulative exposure indices at urban and suburban sites.

Publication Type

Journal contribution (peer reviewed)

Authors

Klumpp, A., Ansel, W., Klumpp, G., Calatayud, V., Garrec, J. P., He, S., Peñuelas, J., Ribas, A., Ro-Poulsen, H., Rasmussen, S., Sanz, M. J., Vergne, P.

Year of publication

2006

Published in

Atmospheric Environment

Band/Volume

40/

Page (from - to)

7963-7974

Keywords

Luftqualitätsvergleich, Luftschadstoff, Ozon

In the frame of a European research project on air quality in urban agglomerations, data on ozone concentrations from
23 automated urban and suburban monitoring stations in 11 cities from seven countries were analysed and evaluated.
Daily and summer mean and maximum concentrations were computed based on hourly mean values, and cumulative
ozone exposure indices (Accumulated exposure Over a Threshold of 40 ppb (AOT40), AOT20) were calculated. The
diurnal profiles showed a characteristic pattern in most city centres, with minimum values in the early morning hours, a
strong rise during the morning, peak concentrations in the afternoon, and a decline during the night. The widest
amplitudes between minimum and maximum values were found in central and southern European cities such as
Du¨ sseldorf, Verona, Klagenfurt, Lyon or Barcelona. In the northern European cities of Edinburgh and Copenhagen, by
contrast, maximum values were lower and diurnal variation was much smaller. Based on ozone concentrations as well as
on cumulative exposure indices, a clear north–south gradient in ozone pollution, with increasing levels from northern and
northwestern sites to central and southern European sites, was observed. Only the Spanish cities did not fit this pattern;
there, ozone levels were again lower than in central European cities, probably due to the direct influence of strong car
traffic emissions. In general, ozone concentrations and cumulative exposure were significantly higher at suburban sites than
at urban and traffic-exposed sites. When applying the newly established European Union (EU) Directive on ozone
pollution in ambient air, it was demonstrated that the target value for the protection of human health was regularly
surpassed at urban as well as suburban sites, particularly in cities in Austria, France, northern Italy and southern Germany. European target values and long-term objectives for the protection of vegetation expressed as AOT40 were also
exceeded at many monitoring sites.