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Ozone levels in Europe during summer 2009 were among the
lowest since comprehensive data reporting started in 1997.
Eighteen EU Member States reported exceeding the information
threshold (ozone concentrations over 180 µg/m³) - with Belgium,
Greece, Italy and Portugal recording the largest number of
exceedances. As in most previous years, no station in northern
Europe registered information threshold exceedances.
Eight EU Member States (Bulgaria, France, Greece, Italy,
Portugal, Romania, Spain and the United Kingdom) reported
exceeding the alert threshold (ozone concentrations of 240
µg/m³).
The record lows in 2009 came despite average summer temperatures
close to those measured in the extremely hot summer of 2003,
which witnessed the highest number of exceedances in the last
decade.
The differing results in the two summers may be attributable
to several factors because ozone formation is determined by
various meteorological conditions, as well as the chemical
composition of the atmosphere. It seems likely, however, that
reductions in anthropogenic ozone precursor gas emissions
in Europe contributed significantly to the general decrease
in peak ozone concentrations.
For the first time since 1997, no concentration higher than
300 µg/m³ was reported. The highest one-hour ozone concentration
(284 µg/m³) was observed in France.
In contrast to previous summers, in 2009 there were no widespread
multi-day episodes. Summer 2009 was characterised by ozone
episodes of between two and five days, followed by spells
with few exceedances.
Whereas ozone forms a protective layer in the stratosphere,
at ground level it is a harmful air pollutant that affects
human health. Sources of ozone precursor emissions include
power plants, cars and trucks and certain paints and solvents.
In the summer, ozone concentrations are worsened by relatively
light winds and higher temperatures.
EU Directive 2002/3/EC
sets the long-term objectives for reducing ground-level ozone
pollution to protect human health and the environment - an
alert threshold (240 µg/m³) and an information threshold (180
µg/m³). Member States must report exceedances of both thresholds
to the European Commission and the European Environment Agency.
As in all previous years, the Directive's long-term objective
to protect human health (maximum ozone concentration of 120
µg/m³ over 8-hours) was exceeded in all EU Member States and
other European countries.
Download report - Air pollution by ozone across Europe
during summer 2009 - Click
Here
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