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Figure 2.6
Eight-hour Average and Daily Maximum Values Observed at Ozone Monitoring Stations Across
Ireland in 2014 (Source: EPA, 2015b)
0
20
40
60
80
100
120
140
160
Zone D
(remainder of country)
Zone C
(21 biggest towns)
Zone B
(Cork)
Zone A
(Dublin)
8-hr daily maximum µg/m
3
Limit value - not to be exceeded >25 times in the calendar year
Figure 2.7
NO
x
Emission Sources and Trends 1990‑2014 (Source: EPA, 2015b)
0
20
40
60
80
100
120
140
160
Other
Transport
Agriculture/Forestry/Fishing
Residential & Commercial
Industrial
Power Stations
NEC Target
2014
2013
2012
2011
2010
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994
1993
1992
1991
1990
29
Chapter 2: Air Quality and Transboundary Air Emissions
stratosphere, where it occurs naturally and plays an
important role in absorbing harmful UV radiation. Ozone
is a powerful oxidising substance whose presence in rural
areas damages crops and vegetation. High concentrations
of ozone affect the functioning of the respiratory
system leading to irritation of the throat and lungs. It is
particularly harmful for those who suffer from respiratory
ailments such as asthma and bronchitis. Ozone levels in
Ireland, which are highly influenced by transboundary
sources, are low in comparison with those in mainland
Europe. Average concentrations in Ireland are generally
below the thresholds for effects on human health and
vegetation set down in the CAFE Directive, but can exceed
the WHO air quality guideline values for ozone.
Other Pollutants
Most controlled air pollutants show low levels in
Ireland
Measured levels for the rest of the legislatively important
pollutants are low in Ireland, with concentrations of SO
2
,
CO, benzene, lead, arsenic, cadmium, nickel and mercury
below all relevant limit and target values (EPA, 2015b).
Quantity of Air Pollutants
Emitted
Transboundary Air Pollutants
Emissions of transboundary pollutants have been
reducing across Europe
Monitoring of transboundary pollutants in Europe is
primarily covered by the 1999 UNECE Gothenburg Protocol
under the Convention on Long-range Transboundary Air
Pollution (CLRTAP) and the EU NEC Directive. Prior to the
Gothenburg Protocol the pollutants that were originally
of concern were the gaseous species NO
x
, SO
2
and VOCs.
These pollutants, which cause acidification, eutrophication
and ground-level ozone formation, have shown declining
concentrations since the introduction of the legislation.
Ammonia (NH
3
) was later included in the list of pollutants
for the Gothenburg Protocol and more recently, with
the replacement of the original legislation with the
2020 Gothenburg Protocol and the 2030 NEC Directive,
emissions ceilings for PM
2.5
have also been introduced. The
current position in Ireland is shown in Table 2.1.