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 8
Low (1)
19
Low (2)
Anglesey Llynfaes
Not measured Not measured Not measured 8
Low (1)
17
Low (2)
Anglesey Penhesgyn 3
Not measured Not measured Not measured 9
Low (1)
19
Low (2)
Aston Hill
64
Low (2)
8
Low (1)
Not measured Not measured Not measured
Caerphilly Blackwood High Street
Not measured 49
Low (1)
Not measured Not measured 16
Low (1)
Caerphilly Fochriw
Not measured Not measured Not measured 6
Low (1)
13
Low (1)
Caerphilly Islwyn Road Wattsville
Not measured 34
Low (1)
Not measured Not measured Not measured
Caerphilly White Street
Not measured 89
Low (2)
Not measured Not measured 20
Low (2)
Cardiff Centre
45
Low (2)
54
Low (1)
203
Low (3)
9
Low (1)
30
Low (2)
Cardiff Newport Road
Not measured 72
Low (2)
Not measured Not measured 26
Low (2)
Chepstow A48
Not measured 109
Low (2)
Not measured 12
Low (2)
22
Low (2)
Cimla Road / Victoria Gardens
Not measured 56
Low (1)
Not measured Not measured Not measured
Cwmbran
71
Low (3)
50
Low (1)
Not measured Not measured 21
Low (2)
Hafod-yr-ynys Roadside
Not measured 156
Low (3)
Not measured Not measured Not measured
Marchlyn Mawr
64
Low (2)
3
Low (1)
Not measured Not measured Not measured
Nantgarw Road
Not measured 47
Low (1)
Not measured Not measured Not measured
Narberth
43
Low (2)
6
Low (1)
9
Low (1)
6
Low (1)
10
Low (1)
Newport M4 Junction 25
39
Low (2)
101
Low (2)
Not measured Not measured Not measured
Newport St Julians Comp School
Not measured 77
Low (2)
Not measured 8
Low (1)
16
Low (1)
Port Talbot Dyffryn School
Not measured Not measured Not measured Not measured 25
Low (2)
Port Talbot Little Warren
Not measured Not measured Not measured Not measured 19
Low (2)
Port Talbot Margam
53
Low (2)
35
Low (1)
23
Low (1)
13
Low (2)
25
Low (2)
Port Talbot Prince Street 2
Not measured Not measured Not measured 10
Low (1)
24
Low (2)
Port Talbot Twll-yn-y-Wal Park
Not measured Not measured Not measured Not measured 35
Low (3)
Rhondda Glyncoch Garth Avenue
Not measured Not measured Not measured Not measured 22
Low (2)
Rhondda Mountain Ash
Not measured 83
Low (2)
Not measured Not measured Not measured
Rhondda Pontypridd Gelliwastad Rd
Not measured 58
Low (1)
Not measured Not measured Not measured
Rhondda-Cynon-Taf Broadway
Not measured 41
Low (1)
Not measured Not measured Not measured
Swansea Cwm Level Park
54
Low (2)
30
Low (1)
Not measured Not measured Not measured
Swansea Hafod DOAS
54
Low (2)
77
Low (2)
Not measured Not measured Not measured
Swansea Morfa Road NOX
Not measured 53
Low (1)
Not measured Not measured Not measured
Swansea Morriston Roadside
Not measured Not measured Not measured Not measured Not measured
Swansea Roadside
Not measured 60
Low (1)
Not measured 11
Low (1)
26
Low (2)
Swansea St Thomas DOAS
72
Low (3)
75
Low (2)
34
Low (1)
Not measured Not measured
Swansea Station Court High Street
Not measured 86
Low (2)
Not measured Not measured Not measured
Twynyrodyn
Not measured Not measured Not measured Not measured Not measured
V Glamorgan Windsor Road Penarth
44
Low (2)
37
Low (1)
Not measured Not measured 26
Low (2)
Wrexham
Not measured 37
Low (1)
4
Low (1)
6
Low (1)
11
Low (1)