Published: 06 Jun 2011
Ground-level ozone is one of the most harmful
air pollutants in Europe today. A new report
by the European Environment Agency (EEA)
shows that despite efforts to
reduce ozone pollution, in 2010 levels continued
to exceed the long-term objective established
in EU legislation to protect human health.
EU Member States will also face difficulties
in meeting the target value, applicable
as of 2010.
Ozone is not directly
emitted to the atmosphere but formed in
complex photochemical reactions from ozone
precursor gases (nitrogen oxides, carbon
monoxide, methane and non-methane volatile
organic compounds). Its production depends
on meteorological conditions such as solar
intensity and temperature. Elevated levels
of ground-level ozone reduce agricultural
crop yields and corrode infrastructure and
cultural heritage. It can also cause health
problems and lead to premature deaths.
The new EEA report ‘Air pollution by ozone
across Europe during summer 2010’ shows
that the long-term objective to protect
human health (maximum daily eight-hour mean
concentration of 120 µg/m3) was exceeded
in all EU Member States and in most of the
other reporting European countries at least
once during summer 2010. As in previous
years, the most widespread concentrations
occurred in the Mediterranean area. However,
areas of western and central Europe experienced
higher ozone concentrations than in 2009.
Preliminary results show that 17 EU Member
States (Austria, Bulgaria, Cyprus, the Czech
Republic, France, Germany, Greece, Hungary,
Italy, Luxembourg, Malta, Poland, Portugal,
Romania, the Slovak Republic, Slovenia and
Spain) are facing difficulties in meeting
the target value for protecting human health.
In all these countries, the maximum daily
eight-hour mean ozone concentration of 120
µg/m3 was exceeded on more than 25
days during summer 2010.
Other key findings
For the first time in four years, in 2010
the information threshold (a one-hour average
ozone concentration of 180 µg/m3)
was exceeded in northern Europe. The average
number of threshold exceedances increased
slightly in north-western, central and eastern
Europe.
The alert threshold
(a one-hour average ozone concentration
of 240 µg/m3) was exceeded 44 times
in nine EU Member States with most exceedances
in northern Italy and northern Portugal.
Summer 2010 was characterised
by a long period with numerous exceedances
during the warm sunny weather experienced
between 24 June and 22 July. This episode
accounted for approximately 85 % of the
total number of exceedances of the information
threshold, 64 % of exceedances of the alert
threshold and 52 % of exceedances of the
long-term objective.
Target value for the protection of human
health
Directive 2008/50/EC on ambient air quality
and cleaner air for Europe sets out the
‘target value for the protection of human
health’. Specifically, as of 2010 the maximum
daily eight-hour mean concentration of ozone
should not exceed 120 µg/m3 on more
than 25 days per calendar year, averaged
over three years. It further specifies that
the target value will first be calculated
using validated data from 2010 and following
years. Therefore it will not be possible
to assess exceedance of the target value
fully until data for 2010, 2011 and 2012
have been compiled and validated.
Ozone pollution – not only a local air quality
issue
In Europe, ozone concentrations in a particular
country are also influenced by emissions
in other northern hemisphere countries and
by poorly regulated sectors such as international
shipping and aviation. Thus, ozone pollution
is not only a local air quality issue but
also a hemispheric and global problem.
Data sources on emissions of ozone precursor
gases
The EEA publishes emissions data on the
air pollutants that contribute to the formation
of ground-level ozone, available in several
data viewers: NEC Directive viewer (NOx,
NMVOCs), LRTAP Convention viewer (CO) and
the greenhouse gas data viewer (CH4). Updated
information on the trends in man-made emissions
of ozone precursors NOx and NMVOCs are also
available in the recently published NEC
Directive status report 2010.
