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 14
Low (2)
30
Low (2)
Anglesey Llynfaes
Not measured Not measured Not measured 4
Low (1)
8
Low (1)
Anglesey Penhesgyn 3
Not measured Not measured Not measured 12
Low (2)
39
Low (3)
Aston Hill
56
Low (2)
8
Low (1)
Not measured Not measured Not measured
Bridgend Park Street
Not measured 64
Low (1)
Not measured Not measured 29
Low (2)
Caerphilly Blackwood High Street
Not measured 65
Low (1)
Not measured Not measured 25
Low (2)
Caerphilly Fochriw
Not measured Not measured Not measured Not measured Not measured
Caerphilly Islwyn Road Wattsville
Not measured 50
Low (1)
Not measured Not measured Not measured
Caerphilly White Street
Not measured 65
Low (1)
Not measured Not measured 31
Low (2)
Cardiff Castle Street
Not measured 69
Low (2)
Not measured 27
Low (3)
37
Low (3)
Cardiff Centre
41
Low (2)
39
Low (1)
3
Low (1)
27
Low (3)
30
Low (2)
Cardiff Newport Road
Not measured 70
Low (2)
Not measured Not measured 39
Low (3)
Chepstow A48
Not measured 68
Low (2)
Not measured 26
Low (3)
36
Low (3)
Cimla Road / Victoria Gardens
Not measured 60
Low (1)
Not measured Not measured Not measured
Cwmbran Crownbridge
48
Low (2)
38
Low (1)
Not measured Not measured 17
Low (2)
Hafod-yr-ynys Roadside
Not measured 88
Low (2)
Not measured Not measured Not measured
Marchlyn Mawr
61
Low (2)
3
Low (1)
Not measured Not measured Not measured
Nantgarw Road
Not measured 44
Low (1)
Not measured Not measured Not measured
Narberth
51
Low (2)
21
Low (1)
4
Low (1)
25
Low (3)
31
Low (2)
Newport M4 Junction 25
26
Low (1)
78
Low (2)
Not measured Not measured Not measured
Newport St Julians Comp School
Not measured No Data Not measured 24
Low (3)
29
Low (2)
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 Not measured
Port Talbot Margam
49
Low (2)
50
Low (1)
5
Low (1)
25
Low (3)
32
Low (2)
Port Talbot Prince Street 2
Not measured Not measured Not measured 24
Low (3)
31
Low (2)
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 34
Low (3)
Rhondda Mountain Ash
Not measured 103
Low (2)
Not measured Not measured Not measured
Rhondda Pontypridd Gelliwastad Rd
Not measured 92
Low (2)
Not measured Not measured Not measured
Rhondda-Cynon-Taf Broadway
Not measured 50
Low (1)
Not measured Not measured Not measured
Swansea Cwm Level Park
31
Low (1)
53
Low (1)
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 57
Low (1)
Not measured 27
Low (3)
Not measured
Swansea Roadside
Not measured 67
Low (1)
Not measured 28
Low (3)
36
Low (3)
Swansea St Thomas DOAS
42
Low (2)
106
Low (2)
36
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 44
Low (1)
No Data 31
Low (3)
40
Low (3)
Wrexham Chirk
Not measured Not measured Not measured Not measured Not measured
Wrexham Chirk Community Hospital
Not measured 37
Low (1)
Not measured 9
Low (1)
21
Low (2)