Published : Aug 14,
2013 Last modified : Aug 14, 2013 11:02
AM
Unusually high temperatures this summer
may be contributing to poor air quality
in many European cities. Thresholds to protect
health from ground-level ozone have been
exceeded across Europe in recent weeks,
according to preliminary data reported to
the European Environment Agency (EEA).
Ozone formation increases
during warm sunny weather depending on the
level of ‘precursor pollutants’ present.
Europe must therefore work hard to reduce
the emissions of pollutants that cause ozone
to protect human health.
Paul McAleavey, Head
of EEA Air and Climate Change Programme
Ozone pollution has
serious effects on health, especially for
older people and children, or those with
asthma and other respiratory problems. Reducing
ozone pollution in the air depends on cutting
the ‘precursor pollutants’ which lead to
ozone formation.
When ozone levels in
the air exceed certain thresholds – either
the ‘Information Threshold’ or the higher
‘Alert Threshold’ – Member States must report
such ‘exceedances’ to the European Commission,
via the EEA, and inform their citizens.
Paul McAleavey, Head
of EEA Air and Climate Change Programme,
said: ‘Ozone formation increases during
warm sunny weather depending on the level
of ‘precursor pollutants’ present. Europe
must therefore work hard to reduce the emissions
of pollutants that cause ozone to protect
human health’.
Ozone exceeding pollutant
thresholds
July this year has been
hotter than usual with warmer than average
temperatures across most of Central and
Western Europe. In July 2013, the average
temperatures in Rome, Prague, Paris and
Copenhagen were among the highest since
1996. These temperatures may have contributed
to increased ozone levels.
Although April, May
and June this year had fewer exceedances
compared to the same period in 2012, the
number of exceedances in July 2013 seems
to be much higher than last year, according
to preliminary data reported to EEA, showing
that the Information Threshold for ozone
was exceeded at approximately a quarter
of all measurement sites in Europe.
In the first half of
July concentrations exceeding the Information
Threshold occurred mainly in northern Italy,
Spain and southern France, but by the second
half of the month similarly high pollutant
concentrations were also found in parts
of northern Europe. Ozone exceeded these
limits in the Paris area (17 July) and in
the Netherlands, Belgium and western Germany
(22 to 23 July). At the end of the month
most of the exceedances were registered
in northern Italy, with high values occasionally
occurring also in the Central European region.
Last summer levels of
ozone were particularly low - the alert
threshold was exceeded the fewest times
since monitoring began in 1997. This is
partly due to efforts to reduce air pollution
in Europe. However, ozone is still a problem,
with more than 98 % of the total EU urban
population potentially exposed to ozone
levels above World Health Organization guidelines
to protect health.
What causes ozone?
Ground-level ozone is
not directly emitted into the atmosphere
but is formed from chemical reactions following
the release of various ‘precursor pollutants’
from a wide variety of sources, for example:
fossil fuel combustion, road transport,
refineries, solvents, vegetation, landfills,
wastewater, livestock and forest fires.
The reactions that create
ozone are catalysed by heat and sunlight
– so it is a particular problem in the summer
months, and southern Europe typically has
much higher levels of ozone than the north.
Excessive ground-level
ozone can cause respiratory problems, trigger
asthma, reduce lung function and cause lung
diseases. The mortality rate rises with
increases in ozone exposure, according to
several European studies. Unlike ozone in
the stratosphere, which protects us from
ultraviolet radiation, high levels of ground-level
or ‘tropospheric’ ozone can also damage
plants, reducing crop yields and forest
growth, and also damage buildings and monuments.
Staying safe from poor
air quality
Children, the elderly,
asthma sufferers and others with respiratory
illnesses are most vulnerable. If ozone
levels are very high, it is advisable for
these groups to avoid spending a lot of
time outdoors. Ozone levels are usually
higher in the afternoon, so vulnerable people
may avoid the higher levels of pollution
by working or exercising outdoors in the
mornings or evenings.
You can find up-to-date
information on ground level ozone concentrations
across the pan-European region at the EEA’s
real-time air quality maps. The site gives
hourly ground level ozone concentrations
for the current situation as well as recent
episodes, based on up-to-date air quality
data measurements. The website provides
data from around 2 000 monitoring sites,
allowing anyone to check air quality in
a specific region or across Europe. Concentration
data for other pollutants (PM10, NO2 and
SO2) can also be found in this viewer.
The EEA website also
provides information on exceedances of the
different ozone thresholds measured this
summer (both calculated from the real-time
data and from the data officially reported
by countries).