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 9
Low (1)
32
Low (2)
Anglesey Llynfaes
Not measured Not measured Not measured 7
Low (1)
24
Low (2)
Anglesey Penhesgyn 3
Not measured Not measured Not measured 8
Low (1)
30
Low (2)
Aston Hill
87
Low (3)
6
Low (1)
Not measured Not measured Not measured
Caerphilly Blackwood High Street
Not measured 25
Low (1)
Not measured Not measured 23
Low (2)
Caerphilly Fochriw
Not measured Not measured Not measured Not measured Not measured
Caerphilly Islwyn Road Wattsville
Not measured 29
Low (1)
Not measured Not measured Not measured
Caerphilly White Street
Not measured Not measured Not measured Not measured Not measured
Cardiff Centre
74
Low (3)
13
Low (1)
2
Low (1)
19
Low (2)
25
Low (2)
Cardiff Newport Road
Not measured 38
Low (1)
Not measured Not measured 34
Low (3)
Chepstow A48
Not measured 39
Low (1)
Not measured 26
Low (3)
37
Low (3)
Cimla Road / Victoria Gardens
Not measured Not measured Not measured Not measured Not measured
Cwmbran
Not measured Not measured Not measured Not measured Not measured
Hafod-yr-ynys Roadside
Not measured 116
Low (2)
Not measured Not measured Not measured
Marchlyn Mawr
101
Moderate (4)
7
Low (1)
Not measured Not measured Not measured
Nantgarw Road
Not measured 21
Low (1)
Not measured Not measured Not measured
Narberth
69
Low (3)
5
Low (1)
10
Low (1)
11
Low (1)
17
Low (2)
Newport M4 Junction 25
55
Low (2)
33
Low (1)
Not measured Not measured Not measured
Newport St Julians Comp School
Not measured 23
Low (1)
Not measured 18
Low (2)
25
Low (2)
Port Talbot Dyffryn School
Not measured Not measured Not measured Not measured 37
Low (3)
Port Talbot Little Warren
Not measured Not measured Not measured Not measured 32
Low (2)
Port Talbot Margam
67
Low (3)
24
Low (1)
3
Low (1)
20
Low (2)
41
Low (3)
Port Talbot Prince Street 2
Not measured Not measured Not measured 20
Low (2)
39
Low (3)
Port Talbot Twll-yn-y-Wal Park
Not measured Not measured Not measured Not measured No Data
Rhondda Glyncoch Garth Avenue
Not measured Not measured Not measured Not measured 34
Low (3)
Rhondda Mountain Ash
Not measured Not measured Not measured Not measured Not measured
Rhondda Pontypridd Gelliwastad Rd
Not measured 22
Low (1)
Not measured Not measured Not measured
Rhondda-Cynon-Taf Broadway
Not measured 32
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
Not measured Not measured 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 Not measured Not measured Not measured Not measured
Swansea Roadside
Not measured 34
Low (1)
Not measured 18
Low (2)
29
Low (2)
Swansea St Thomas DOAS
Not measured Not measured Not measured 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
No Data 24
Low (1)
Not measured Not measured 34
Low (3)
Wrexham
Not measured 34
Low (1)
25
Low (1)
19
Low (2)
29
Low (2)