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)
13
Low (1)
Anglesey Llynfaes
Not measured Not measured Not measured 3
Low (1)
11
Low (1)
Anglesey Penhesgyn 3
Not measured Not measured Not measured 4
Low (1)
7
Low (1)
Aston Hill
78
Low (3)
2
Low (1)
Not measured Not measured Not measured
Bridgend Park Street
Not measured 76
Low (2)
Not measured Not measured 18
Low (2)
Caerphilly Blackwood High Street
Not measured 48
Low (1)
Not measured Not measured 13
Low (1)
Caerphilly Fochriw
Not measured Not measured Not measured Not measured Not measured
Caerphilly Islwyn Road Wattsville
Not measured 47
Low (1)
Not measured Not measured Not measured
Caerphilly White Street
Not measured 54
Low (1)
Not measured Not measured 14
Low (1)
Cardiff Castle Street
Not measured 100
Low (2)
Not measured 7
Low (1)
17
Low (2)
Cardiff Centre
62
Low (2)
54
Low (1)
10
Low (1)
5
Low (1)
10
Low (1)
Cardiff Newport Road
Not measured 58
Low (1)
Not measured Not measured 11
Low (1)
Chepstow A48
Not measured 46
Low (1)
Not measured 6
Low (1)
13
Low (1)
Cimla Road / Victoria Gardens
Not measured 72
Low (2)
Not measured Not measured Not measured
Cwmbran Crownbridge
74
Low (3)
13
Low (1)
Not measured Not measured 11
Low (1)
Hafod-yr-ynys Roadside
Not measured 112
Low (2)
Not measured Not measured Not measured
Marchlyn Mawr
80
Low (3)
3
Low (1)
Not measured Not measured Not measured
Nantgarw Road
Not measured 61
Low (1)
Not measured Not measured Not measured
Narberth
74
Low (3)
3
Low (1)
3
Low (1)
2
Low (1)
6
Low (1)
Newport M4 Junction 25
40
Low (2)
70
Low (2)
Not measured Not measured Not measured
Newport St Julians Comp School
Not measured 25
Low (1)
Not measured 4
Low (1)
7
Low (1)
Port Talbot Dyffryn School
Not measured Not measured Not measured Not measured Not measured
Port Talbot Little Warren
Not measured Not measured Not measured Not measured 14
Low (1)
Port Talbot Margam
68
Low (3)
30
Low (1)
62
Low (1)
4
Low (1)
21
Low (2)
Port Talbot Prince Street 2
Not measured Not measured Not measured Not measured Not measured
Port Talbot Twll-yn-y-Wal Park
Not measured Not measured Not measured Not measured Not measured
Rhondda Glyncoch Garth Avenue
Not measured Not measured Not measured Not measured 8
Low (1)
Rhondda Mountain Ash
Not measured 77
Low (2)
Not measured Not measured Not measured
Rhondda Pontypridd Gelliwastad Rd
Not measured 61
Low (1)
Not measured Not measured Not measured
Rhondda-Cynon-Taf Broadway
Not measured 46
Low (1)
Not measured Not measured Not measured
Swansea Cwm Level Park
Not measured Not measured Not measured Not measured Not measured
Swansea Hafod DOAS
75
Low (3)
85
Low (2)
Not measured Not measured Not measured
Swansea Morfa Road NOX
Not measured 64
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 70
Low (2)
Not measured 8
Low (1)
Not measured
Swansea Roadside
Not measured 53
Low (1)
Not measured 7
Low (1)
No Data
Swansea St Thomas DOAS
69
Low (3)
85
Low (2)
5
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
Wrexham
Not measured 45
Low (1)
4
Low (1)
2
Low (1)
5
Low (1)
Wrexham Chirk
Not measured 41
Low (1)
Not measured 3
Low (1)
8
Low (1)