24 Hour Summary

The maximum pollutant concentrations measured during the last 24 hours across Wales are shown below. Summary graphs showing the last seven days are available for each pollutant in the left hand column of the table.

Site 8 Hour mean
Ozone
µgm-3
Hourly mean
Nitrogen dioxide
µgm-3
Max 15 min mean
Sulphur dioxide
µgm-3
Running 24 Hour mean
PM2.5
Particles
µgm-3
Running 24 Hour mean
PM10
Particles
µgm-3
Anglesey Brynteg
Not measured Not measured Not measured 6
Low (1)
16
Low (1)
Anglesey Llynfaes
Not measured Not measured Not measured 7
Low (1)
36
Low (3)
Anglesey Penhesgyn 3
Not measured Not measured Not measured 10
Low (1)
21
Low (2)
Aston Hill
60
Low (2)
8
Low (1)
Not measured Not measured Not measured
Caerphilly Blackwood High Street
Not measured 47
Low (1)
Not measured Not measured 18
Low (2)
Caerphilly Fochriw
Not measured Not measured Not measured 5
Low (1)
7
Low (1)
Caerphilly Islwyn Road Wattsville
Not measured 47
Low (1)
Not measured Not measured Not measured
Caerphilly White Street
Not measured 82
Low (2)
Not measured Not measured 20
Low (2)
Cardiff Centre
42
Low (2)
48
Low (1)
2
Low (1)
20
Low (2)
23
Low (2)
Cardiff Newport Road
Not measured 78
Low (2)
Not measured Not measured 26
Low (2)
Chepstow A48
Not measured 57
Low (1)
Not measured 19
Low (2)
21
Low (2)
Cimla Road / Victoria Gardens
Not measured 78
Low (2)
Not measured Not measured Not measured
Cwmbran
39
Low (2)
23
Low (1)
Not measured Not measured 16
Low (1)
Hafod-yr-ynys Roadside
Not measured 133
Low (2)
Not measured Not measured Not measured
Marchlyn Mawr
74
Low (3)
3
Low (1)
Not measured Not measured Not measured
Nantgarw Road
Not measured 58
Low (1)
Not measured Not measured Not measured
Narberth
35
Low (2)
11
Low (1)
5
Low (1)
8
Low (1)
10
Low (1)
Newport M4 Junction 25
23
Low (1)
50
Low (1)
Not measured Not measured Not measured
Newport St Julians Comp School
Not measured 69
Low (2)
Not measured 15
Low (2)
19
Low (2)
Port Talbot Dyffryn School
Not measured Not measured Not measured Not measured 32
Low (2)
Port Talbot Little Warren
Not measured Not measured Not measured Not measured 35
Low (3)
Port Talbot Margam
17
Low (1)
51
Low (1)
2
Low (1)
No Data 29
Low (2)
Port Talbot Prince Street 2
Not measured Not measured Not measured 19
Low (2)
26
Low (2)
Port Talbot Twll-yn-y-Wal Park
Not measured Not measured Not measured Not measured 26
Low (2)
Rhondda Glyncoch Garth Avenue
Not measured Not measured Not measured Not measured 33
Low (2)
Rhondda Mountain Ash
Not measured 87
Low (2)
Not measured Not measured Not measured
Rhondda Pontypridd Gelliwastad Rd
Not measured 78
Low (2)
Not measured Not measured Not measured
Rhondda-Cynon-Taf Broadway
Not measured Not measured Not measured Not measured Not measured
Swansea Cwm Level Park
Not measured Not measured Not measured Not measured Not measured
Swansea Hafod DOAS
21
Low (1)
89
Low (2)
Not measured Not measured Not measured
Swansea Morfa Road NOX
Not measured Not measured Not measured Not measured Not measured
Swansea Morriston Roadside
Not measured Not measured Not measured Not measured Not measured
Swansea Port Tennant Roadside
Not measured 58
Low (1)
Not measured 26
Low (3)
Not measured
Swansea Roadside
Not measured 67
Low (1)
Not measured 21
Low (2)
30
Low (2)
Swansea St Thomas DOAS
42
Low (2)
87
Low (2)
10
Low (1)
Not measured Not measured
Swansea Station Court High Street
Not measured Not measured Not measured Not measured Not measured
Twynyrodyn
Not measured Not measured Not measured Not measured Not measured
V Glamorgan Windsor Road Penarth
25
Low (1)
57
Low (1)
Not measured Not measured 18
Low (2)
Wrexham
Not measured 74
Low (2)
16
Low (1)
13
Low (2)
16
Low (1)