Air quality standards

View real-time air quality up-to-date information for air monitoring locations.

The Environmental Protection Agency manages the ambient air quality monitoring network.

 

In order to protect our health, vegetation and ecosystems, EU directives set down air quality standards in Ireland and the other member states for a wide variety of pollutants. These rules include how we should monitor, assess and manage ambient air quality.

The European Commission set down the principles to this approach in 1996 with its Air Quality Framework Directive. Four "daughter" directives lay down limits for specific pollutants:

  • 1st Daughter Directive: Sulphur dioxide, nitrogen dioxide and oxides of nitrogen, particulate matter and lead
  • 2nd Daughter Directive: Carbon monoxide and benzene
  • 3rd Daughter Directive: Ozone
  • 4th Daughter Directive: Polyaromatic hydrocarbons, arsenic, nickel, cadmium and mercury in ambient air

The Ambient Air Quality and Cleaner Air for Europe (CAFE) Directive (2008/50/EC) was published in May 2008.  It replaced the Framework Directive and the first, second and third Daughter Directives.  The fourth Daughter Directive (2004/107/EC) will be included in CAFE at a later stage. The limit and target values for both Directives are outlined below.

The CAFE Directive was transposed into Irish legislation by the Air Quality Standards Regulations 2011 (S.I. No. 180 of 2011). It replaces the Air Quality Standards Regulations 2002 (S.I. No. 271 of 2002), the Ozone in Ambient Air Regulations 2004 (S.I. No. 53 of 2004) and S.I. No. 33 of 1999.

The fourth Daughter Directive was transponsed into Irish legislation by the Arsenic, Cadmium, Mercury, Nickel and Polycyclic Aromatic Hydrocarbons in Ambient Air Regulations 2009 (S.I. No. 58 of 2009).

Links to EU and Irish ambient air quality legislation currently in force

Directives set targets for air quality

The following tables show the limit or target values specified by the five published directives that set down limits for specific air pollutants. The directives cover:

  • Sulphur dioxide, nitrogen dioxide and oxides of nitrogen, particulate matter (PM10 and PM2.5) and lead
  • Carbon monoxide and benzene
  • Ozone
  • Arsenic, Cadmium, Nickel and Benzo(a)pyrene

Check the bottom of this article for explanations of the abbreviations used.

Limit values of CAFE Directive 2008/50/EC

PollutantLimit Value ObjectiveAveraging PeriodLimit Value
ug/m3
Limit Value
ppb
Basis of Application of the Limit ValueLimit Value Attainment Date
SO2 Protection of human health 1 hour 350 132 Not to be exceeded more than 24 times in a calendar year 1 Jan 2005
SO2 Protection of human health 24 hours 125 47 Not to be exceeded more than 3 times in a calendar year 1 Jan 2005
SO2 Protection of vegetation calendar year 20 7.5 Annual mean 19 July 2001
SO2 Protection of vegetation 1 Oct to 31 Mar 20 7.5 Winter mean 19 July 2001
NO2 Protection of human health 1 hour 200 105 Not to be exceeded more than 18 times in a calendar year 1 Jan 2010
NO2 Protection of human health calendar year 40 21 Annual mean 1 Jan 2010
NO + NO 2 Protection of ecosystems calendar year 30 16 Annual mean 19 July 2001
PM10  Protection of human health 24 hours 50   Not to be exceeded more than 35 times in a calendar year 1 Jan 2005
PM10  Protection of human health calendar year 40   Annual mean 1 Jan 2005

PM2.5 -

Stage 1

Protection of human health calendar year 25   Annual mean 1 Jan 2015

PM2.5 -

Stage 2 

Protection of human health calendar year 20   Annual mean 1 Jan 2020
Lead Protection of human health calendar year 0.5   Annual mean 1 Jan 2005
 Carbon Monoxide Protection of human health 8 hours 10,000  8620 Not to be exceeded 1 Jan 2005
Benzene  Protection of human health  calendar year 5 1.5  Annual mean  1 Jan 2010

Alert thresholds

The public must be informed if the following thresholds are exceeded for three consecutive hours.

PollutantAveraging PeriodLimit Value
Sulphur Dioxide 1 hour 500 ug/m3
Nitrogen Dioxide 1 hour 400 ug/m3

 

Target values and long-term objectives of CAFE Directive 2008/50/EC

Target values for ozone from 2010

ObjectiveParameterValue
Protection of human health Maximum daily 8 hour mean 120 ug/m3 not to be exceeded more than 25 days per calendar year averaged over 3 years
Protection of vegetation AOT40, calculated from 1 hour values from May to July 18000 ug/m3-h averaged over 5 years

Long-term objectives for ozone from 2020

ObjectiveParameterValue
Protection of human health Maximum daily 8 hour mean 120 ug/m3
Protection of vegetation AOT40, calculated from 1 hour values from May to July 6000 ug/m3-h

The public must be informed if ozone levels exceed the following thresholds

 ParameterThreshold
Information Threshold 1 hour average 180 ug/m3
Alert Threshold 1 hour average 240 ug/m3

 Target Values of Directive 2004/107/EC

 PollutantLimit Value Objective  Averaging Period

Target Value ng/m3 

 Limit Value Attainment Date
 Arsenic  Protection of human health  calendar year  6  31 Dec 2012
 Cadmium  Protection of human health  calendar year  5  31 Dec 2012
 Nickel  Protection of human health   calendar year  20  31 Dec 2012
Benzo(a)pyrene  Protection of human health  calendar year 1  31 Dec 2012

 

Nitrogen dioxide 1 ppb = 1.91 ug/m3
Sulphur dioxide 1 ppb = 2.66 ug/m3
Ozone 1 ppb = 2.0 ug/m3
Carbon monoxide 1 ppb = 1.16 ug/m3
Benzene 1 ppb = 3.24 ug/m3

An example of calculating the AOT40 

The following is a worked example:

Local Time IrelandCentral European TimeOzone Concentration ug/m3Difference between previous column and 80 ug/m3
23:00 00:00 63 Not counted before 08:00
00:00 01:00 70 Not counted before 08:00
01:00 02:00 65 Not counted before 08:00
02:00 03:00 63 Not counted before 08:00
03:00 04:00 45 Not counted before 08:00
04:00 05:00 54 Not counted before 08:00
05:00 06:00 56 Not counted before 08:00
06:00 07:00 55 Not counted before 08:00
07:00 08:00 55 Only values greater than 80 count
08:00 09:00 62 0
09:00 10:00 51 0
10:00 11:00 70 0
11:00 12:00 92 12
12:00 13:00 90 10
13:00 14:00 82 2
14:00 15:00 87 7
15:00 16:00 91 11
16:00 17:00 90 10
17:00 18:00 89 9
18:00 19:00 84 4
19:00 20:00 85 Not counted after 20:00
20:00 21:00 83 Not counted after 20:00
21:00 22:00 70 Not counted after 20:00
22:00 23:00 60 Not counted after 20:00
AOT40 = sum of values in the 4th column = 65 ug/m3 hours

Abbreviations used

  • ug/m3 - micrograms per cubic metre
  • ng/m3 - nanograms per cubic metre
  • ppb - parts per billion
  • NO2 - Nitrogen Dioxide
  • NO - Nitric Oxide
  • SO2 - Sulphur Dioxide
  • PM10 - Particulate Matter with a diameter less than 10 microns
  • PM2.5- Particulate Matter with a diameter less than 2.5 microns
  • AOT40 - This is a measure of the overall exposure of plants to ozone. It is the sum of the excess hourly concentrations greater than 80 ug/m3 and is expressed as ug/m3 hours. Only values measured between 08:00 and 20:00 Central European Time each day from May to July are used for the calculation. (The name AOT40 refers to 40ppb which is the same as 80 ug/m3)

Conversion factors from ppb to ug/m3