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 35
Low (3)
53
Moderate (4)
Anglesey Llynfaes
Not measured Not measured Not measured 36
Moderate (4)
54
Moderate (4)
Anglesey Penhesgyn 3
Not measured Not measured Not measured 28
Low (3)
41
Low (3)
Aston Hill
84
Low (3)
1
Low (1)
Not measured Not measured Not measured
Caerphilly Blackwood High Street
Not measured 37
Low (1)
Not measured Not measured 21
Low (2)
Caerphilly Fochriw
Not measured Not measured Not measured 7
Low (1)
13
Low (1)
Caerphilly Islwyn Road Wattsville
Not measured Not measured Not measured Not measured Not measured
Caerphilly White Street
Not measured 9
Low (1)
Not measured Not measured 24
Low (2)
Cardiff Centre
75
Low (3)
18
Low (1)
23
Low (1)
6
Low (1)
24
Low (2)
Cardiff Newport Road
Not measured 17
Low (1)
Not measured Not measured 25
Low (2)
Chepstow A48
Not measured 49
Low (1)
Not measured 8
Low (1)
24
Low (2)
Cimla Road / Victoria Gardens
Not measured 46
Low (1)
Not measured Not measured Not measured
Cwmbran
83
Low (3)
4
Low (1)
Not measured Not measured 26
Low (2)
Hafod-yr-ynys Roadside
Not measured 44
Low (1)
Not measured Not measured Not measured
Marchlyn Mawr
56
Low (2)
2
Low (1)
Not measured Not measured Not measured
Nantgarw Road
Not measured 40
Low (1)
Not measured Not measured Not measured
Narberth
78
Low (3)
1
Low (1)
3
Low (1)
11
Low (1)
18
Low (2)
Newport M4 Junction 25
70
Low (3)
43
Low (1)
Not measured Not measured Not measured
Newport St Julians Comp School
Not measured 18
Low (1)
Not measured 11
Low (1)
23
Low (2)
Port Talbot Dyffryn School
Not measured Not measured Not measured Not measured 49
Low (3)
Port Talbot Little Warren
Not measured Not measured Not measured Not measured 29
Low (2)
Port Talbot Margam
72
Low (3)
30
Low (1)
259
Low (3)
22
Low (2)
75
Moderate (6)
Port Talbot Prince Street 2
Not measured Not measured Not measured 17
Low (2)
52
Moderate (4)
Port Talbot Twll-yn-y-Wal Park
Not measured Not measured Not measured Not measured 57
Moderate (4)
Rhondda Glyncoch Garth Avenue
Not measured Not measured Not measured Not measured 22
Low (2)
Rhondda Mountain Ash
Not measured Not measured Not measured Not measured Not measured
Rhondda Pontypridd Gelliwastad Rd
Not measured 51
Low (1)
Not measured Not measured Not measured
Rhondda-Cynon-Taf Broadway
Not measured 39
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 15
Low (1)
Not measured 10
Low (1)
33
Low (2)
Swansea St Thomas DOAS
99
Low (3)
37
Low (1)
2
Low (1)
Not measured Not measured
Swansea Station Court High Street
Not measured 180
Low (3)
Not measured Not measured Not measured
Twynyrodyn
Not measured Not measured Not measured Not measured Not measured
V Glamorgan Windsor Road Penarth
77
Low (3)
21
Low (1)
Not measured Not measured 25
Low (2)
Wrexham
Not measured 7
Low (1)
12
Low (1)
5
Low (1)
9
Low (1)