Limit
Values for Pollutants Measured Limit
Values for Pollutants Measured
The Environmental Protection Agency Act 1992 (Ambient Air Quality Assessment and Management) Regulations 1999 (S.I. No. 33 of 1999) and the Air Quality Standards Regulations 2002 (S.I. No. 271 of 2002) transpose Council Directive 96/62/EC and the first two daughter directives, Council Directive 1999/30/EC and Council Directive 2000/69/EC into Irish law. The 2002 regulations came into force on 17th June 2002; they deal with sulphur dioxide, nitrogen dioxide and oxides of nitrogen, particulate matter, lead, carbon monoxide and benzene in ambient air.
A third daughter directive, Council Directive 2002/3/EC relating to ozone was published in February 2002 and was transposed into Irish law by S.I. No. 53 of 2004.
The fourth daughter directive has not yet been finalised. It will deal with polyaromatic hydrocarbons, arsenic, nickel, cadmium and mercury in ambient air.
The tables below set out the limit values or target values specified by the three published daughter directives.
Click here for an explanation of the abbreviations used
Limit Values of Directive 1999/30/EC
Pollutant |
Limit
Value Objective |
Averaging Period |
Limit
Value ug/m3 |
Limit Value ppb |
Basis
of Application of the Limit Value |
Limit Value Attainment Date |
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 |
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
+ NO2 |
Protection
of ecosystems |
calendar
year |
30 |
16 |
Annual
mean |
19 July 2001 |
PM10
- Stage 1 |
Protection
of human health |
24
hours |
50 |
Not
to be exceeded more than 35 times in a calendar year |
1 Jan 2005 | |
PM10
- Stage 1 |
Protection
of human health |
calendar
year |
40 |
Annual
mean |
1 Jan 2005 | |
PM10
- Stage 2 |
Protection
of human health |
24
hours |
50 |
Not
to be exceeded more than 7 times in a calendar year |
1 Jan 2010 | |
PM10
- Stage 2 |
Protection
of human health |
calendar
year |
20 |
Annual
mean |
1 Jan 2010 | |
Lead |
Protection
of human health |
calendar
year |
0.5 |
Annual
mean |
1 Jan 2005 |
Alert Thresholds
The public must be informed if the following thresholds are exceeded for three consecutive hours.
Pollutant |
Averaging
Period |
Limit
Value |
Sulphur
Dioxide |
1
hour |
500 ug/m3 |
Nitrogen
Dioxide |
1
hour |
400
ug/m3 |
Limit Values of Directive 2000/59/EC
Pollutant |
Limit
Value Objective |
Averaging Period |
Limit
Value ug/m3 |
Limit
Value ppb |
Limit
Value Attainment Date |
Carbon
Monoxide |
Protection
of human health |
8
hours |
1000 |
862 |
1
Jan 2005 |
Benzene |
Protection
of human health |
calendar
year |
5 |
1.5 |
1
Jan 2010 |
Target Values and Long Term Objectives of Directive 2002/3/EC
The ozone daughter directive is different from the previous two in that it sets target values and long term objectives for ozone levels rather than limit values. They are as follows:
Target Values for Ozone from 2010
Objective |
Parameter |
Value |
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
Objective |
Parameter |
Value |
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 |
Information and Alert Thresholds
The public must be informed if ozone levels exceed the following thresholds.
Parameter |
Threshold |
|
Information
Threshold |
1
hour average |
180
ug/m3 |
Alert
Threshold |
1
hour average |
240
ug/m3 |
Conversion factors from ppb to ug/m3
| 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 |
List of Abbreviations
ug/m3 - micrograms per cubic metre
NO2 - Nitrogen Dioxide
SO2 - Sulphur Dioxide
PM10 - Particulate Matter with a diameter less than 10 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).
The following is a worked example:
Local
Time Ireland |
Central
European Time |
Ozone Concentration ug/m3 |
Difference
between previous column and 80 ug/m3 |
23:00 |
00:00 |
63 |
Not
counted before 08:00
|
00:00 |
01:00 |
70 |
|
01:00 |
02:00 |
65 |
|
02:00 |
03:00 |
63 |
|
03:00 |
04:00 |
45 |
|
04:00 |
05:00 |
54 |
|
05:00 |
06:00 |
56 |
|
06:00 |
07:00 |
55 |
|
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 |
|
21:00 |
22:00 |
70 |
|
22:00 |
23:00 |
60 |
|
AOT40
= sum of values in the 4th column = |
65
ug/m3 hours |
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