Chemistry Reference
In-Depth Information
metric as recommended by WHO for the assessment and evaluation of ozone
monitoring data.
It was accepted at an early stage that the problems associatedwith the occurrence of
elevated ozone levels require concerted international action [
10
]. This is because
elevated levels are widespread across Europe and impact on almost all European
countries. Furthermore, efficient long-range transboundary formation and transport
means that countries benefit not only from the results of their own policy actions but
also those of their neighbouring countries. Policy actions to reduce episodic peak
ozone levels were first coordinated through the United Nations Economic
Commission for Europe (UNECE) and its international Convention on Long-Range
Transboundary Air Pollution (CLRTAP). Initially, the CLRTAP focused on
man-made NO
x
emissions through its NO
x
Protocol [
11
]. Then the focus shifted to
VOC emissions through the VOC Protocol [
12
].Theagreedreductionsinman-made
NO
x
and VOC emissions were delivered by a series of mandatory motor vehicle
emissions Directives promulgated by the Commission of the European Communities
[
13
]. Subsequently, the CLRTAP agreed its multi-pollutant multi-effect Gothenburg
Protocol with the aim of reducing simultaneously acid rain, ground-level ozone
formation and eutrophication [
14
]. The Commission of the European Communities
formulated its National Emissions Ceilings [
15
] and Solvent Emissions [
16
]
Directives to control emissions of NO
x
and VOCs from stationary sources. Subse-
quently, the European Union (EU) has brought all of its air quality policy formulation
activities together under its Clean Air for Europe Thematic Strategy [
17
].
In this chapter, the impact of these policy actions on elevated episodic peak
ozone levels is assessed over the 1980-2009 period. The annual maximum 8-h
average ozone level is the chosen air quality metric, and the focus is mainly on rural
and remote monitoring stations as recorded in the EMEP ozone database.
2 Spatial Distribution of Episodic Peak Ozone Levels
Across Europe
Over recent years, several annual reviews of European ozone data have been
compiled, and these give an authoritative assessment of the state of European
ozone air quality. The Chemical Coordination Centre of EMEP publishes an annual
digest of the rural ozone monitoring data [
18
], based on the EMEP ozone monitoring
network. The European Topic Centre on Air and Climate Change of the European
Environment Agency also publishes summaries [
19
] of the AIRBASE database
which holds ozone monitoring data for a wide range of urban and rural ozone
monitoring stations. There is a degree of overlap between the EMEP and AIRBASE
ozone databases in that they both contain largely the same reported rural ozone
monitoring data.
In this chapter, focus is given to the EMEP ozone monitoring network which began
collecting rural ozone monitoring data in the 1980s as a continuation of the OXIDATE
