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
Aston Expressway A494 Deeside
Not measured Not measured Not measured Not measured Not measured
Aston Hill
22
Low (1)
9
Low (1)
Not measured Not measured Not measured
Bridgend Park Street
Not measured 30
Low (1)
Not measured Not measured 37
Low (3)
Caerphilly Blackwood High Street
Not measured Not measured Not measured Not measured Not measured
Caerphilly Fochriw
Not measured Not measured Not measured 26
Low (3)
Not measured
Caerphilly Islwyn Road Wattsville
Not measured 19
Low (1)
Not measured Not measured Not measured
Caerphilly White Street
Not measured Not measured Not measured Not measured Not measured
Cardiff Castle Street
Not measured Not measured Not measured Not measured Not measured
Cardiff Centre
12
Low (1)
18
Low (1)
1
Low (1)
32
Low (3)
38
Low (3)
Cardiff Newport Road
Not measured 37
Low (1)
Not measured Not measured 46
Low (3)
Chepstow A48
Not measured 26
Low (1)
Not measured 30
Low (3)
42
Low (3)
Cimla Road / Victoria Gardens
Not measured Not measured Not measured Not measured Not measured
Cwmbran Crownbridge
12
Low (1)
32
Low (1)
Not measured Not measured Not measured
Hafod-yr-ynys Hill Roadside
Not measured 14
Low (1)
Not measured Not measured Not measured
Marchlyn Mawr
Not measured 1
Low (1)
Not measured Not measured Not measured
Nantgarw Road
Not measured 31
Low (1)
Not measured Not measured Not measured
Narberth
23
Low (1)
10
Low (1)
2
Low (1)
22
Low (2)
28
Low (2)
Newport M4 Junction 25
Not measured Not measured Not measured Not measured Not measured
Newport M4 Junction 25 West
Not measured Not measured Not measured Not measured Not measured
Newport St Julians Comp School
Not measured 24
Low (1)
Not measured 34
Low (3)
43
Low (3)
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 M4 Junction 41
Not measured Not measured Not measured Not measured Not measured
Port Talbot Margam
11
Low (1)
14
Low (1)
1
Low (1)
23
Low (2)
31
Low (2)
Port Talbot Prince Street 2
Not measured Not measured Not measured Not measured Not measured
Rhondda Glyncoch Garth Avenue
Not measured Not measured Not measured Not measured Not measured
Rhondda Mountain Ash
Not measured 42
Low (1)
Not measured Not measured Not measured
Rhondda Pontypridd Gelliwastad Rd
Not measured Not measured Not measured Not measured Not measured
Rhondda-Cynon-Taf Broadway
Not measured Not measured Not measured Not measured Not measured
Rhondda-Cynon-Taf Pontypridd A470
Not measured Not measured Not measured Not measured Not measured
Swansea Cwm Level Park
9
Low (1)
39
Low (1)
Not measured Not measured Not measured
Swansea Hafod DOAS
29
Low (1)
59
Low (1)
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 20
Low (1)
Not measured 19
Low (2)
28
Low (2)
Swansea St Thomas DOAS
25
Low (1)
47
Low (1)
3
Low (1)
Not measured Not measured
Swansea Station Court High Street
Not measured Not measured Not measured Not measured Not measured
Wrexham
Not measured 14
Low (1)
4
Low (1)
33
Low (3)
38
Low (3)
Wrexham A483
Not measured Not measured Not measured Not measured Not measured
Wrexham Chirk
Not measured Not measured Not measured Not measured Not measured
Wrexham Chirk Community Hospital
Not measured Not measured Not measured Not measured Not measured