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 2
Low (1)
9
Low (1)
Anglesey Llynfaes
Not measured Not measured Not measured Not measured Not measured
Anglesey Penhesgyn 3
Not measured Not measured Not measured Not measured Not measured
Aston Hill
67
Low (3)
15
Low (1)
Not measured Not measured Not measured
Caerphilly Blackwood High Street
Not measured 75
Low (2)
Not measured Not measured 7
Low (1)
Caerphilly Fochriw
Not measured Not measured Not measured 1
Low (1)
4
Low (1)
Caerphilly Islwyn Road Wattsville
Not measured 53
Low (1)
Not measured Not measured Not measured
Caerphilly White Street
Not measured 72
Low (2)
Not measured Not measured No Data
Cardiff Castle Street
Not measured 67
Low (1)
Not measured 6
Low (1)
8
Low (1)
Cardiff Centre
49
Low (2)
46
Low (1)
2
Low (1)
4
Low (1)
4
Low (1)
Cardiff Newport Road
Not measured 59
Low (1)
Not measured Not measured 7
Low (1)
Chepstow A48
Not measured 77
Low (2)
Not measured 5
Low (1)
8
Low (1)
Cimla Road / Victoria Gardens
Not measured 90
Low (2)
Not measured Not measured Not measured
Cwmbran Crownbridge
63
Low (2)
21
Low (1)
Not measured Not measured 5
Low (1)
Hafod-yr-ynys Roadside
Not measured 162
Low (3)
Not measured Not measured Not measured
Marchlyn Mawr
67
Low (3)
8
Low (1)
Not measured Not measured Not measured
Nantgarw Road
Not measured 64
Low (1)
Not measured Not measured Not measured
Narberth
71
Low (3)
4
Low (1)
2
Low (1)
1
Low (1)
3
Low (1)
Newport M4 Junction 25
43
Low (2)
95
Low (2)
Not measured Not measured Not measured
Newport St Julians Comp School
Not measured 51
Low (1)
Not measured 2
Low (1)
4
Low (1)
Port Talbot Dyffryn School
Not measured Not measured Not measured Not measured 8
Low (1)
Port Talbot Little Warren
Not measured Not measured Not measured Not measured 5
Low (1)
Port Talbot Margam
61
Low (2)
34
Low (1)
51
Low (1)
3
Low (1)
8
Low (1)
Port Talbot Prince Street 2
Not measured Not measured Not measured 9
Low (1)
14
Low (1)
Port Talbot Twll-yn-y-Wal Park
Not measured Not measured Not measured Not measured 7
Low (1)
Rhondda Glyncoch Garth Avenue
Not measured Not measured Not measured Not measured 4
Low (1)
Rhondda Mountain Ash
Not measured 91
Low (2)
Not measured Not measured Not measured
Rhondda Pontypridd Gelliwastad Rd
Not measured 77
Low (2)
Not measured Not measured Not measured
Rhondda-Cynon-Taf Broadway
Not measured 66
Low (1)
Not measured Not measured Not measured
Swansea Cwm Level Park
No Data 54
Low (1)
Not measured Not measured Not measured
Swansea Hafod DOAS
61
Low (2)
89
Low (2)
Not measured Not measured Not measured
Swansea Morfa Road NOX
Not measured 62
Low (1)
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 77
Low (2)
Not measured 4
Low (1)
Not measured
Swansea Roadside
Not measured 45
Low (1)
Not measured 4
Low (1)
7
Low (1)
Swansea St Thomas DOAS
68
Low (3)
63
Low (1)
2
Low (1)
Not measured Not measured
Swansea Station Court High Street
Not measured 122
Low (2)
Not measured Not measured Not measured
Twynyrodyn
Not measured Not measured Not measured Not measured Not measured
V Glamorgan Windsor Road Penarth
61
Low (2)
67
Low (1)
Not measured Not measured 8
Low (1)
Wrexham
Not measured 66
Low (1)
10
Low (1)
5
Low (1)
7
Low (1)
Wrexham Chirk
Not measured 56
Low (1)
Not measured No Data 2
Low (1)