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 Hill
57
Low (2)
1
Low (1)
Not measured Not measured Not measured
Bridgend Park Street
Not measured Not measured Not measured Not measured Not measured
Caerphilly Blackwood High Street
Not measured Not measured Not measured Not measured 10
Low (1)
Caerphilly Fochriw
Not measured Not measured Not measured 1
Low (1)
4
Low (1)
Caerphilly Islwyn Road Wattsville
Not measured 9
Low (1)
Not measured Not measured Not measured
Caerphilly White Street
Not measured 10
Low (1)
Not measured Not measured 10
Low (1)
Cardiff Castle Street
Not measured 27
Low (1)
Not measured 3
Low (1)
11
Low (1)
Cardiff Centre
43
Low (2)
7
Low (1)
1
Low (1)
4
Low (1)
7
Low (1)
Cardiff Newport Road
Not measured 5
Low (1)
Not measured Not measured 8
Low (1)
Chepstow A48
Not measured 36
Low (1)
Not measured 3
Low (1)
10
Low (1)
Cimla Road / Victoria Gardens
Not measured Not measured Not measured Not measured Not measured
Cwmbran Crownbridge
52
Low (2)
3
Low (1)
Not measured Not measured 9
Low (1)
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 13
Low (1)
Not measured Not measured Not measured
Narberth
38
Low (2)
1
Low (1)
2
Low (1)
3
Low (1)
6
Low (1)
Newport M4 Junction 25
29
Low (1)
56
Low (1)
Not measured Not measured Not measured
Newport St Julians Comp School
Not measured 6
Low (1)
Not measured 3
Low (1)
7
Low (1)
Port Talbot Dyffryn School
Not measured Not measured Not measured 3
Low (1)
13
Low (1)
Port Talbot Little Warren
Not measured Not measured Not measured 3
Low (1)
Not measured
Port Talbot Margam
40
Low (2)
12
Low (1)
1
Low (1)
8
Low (1)
20
Low (2)
Port Talbot Prince Street 2
Not measured Not measured Not measured 4
Low (1)
17
Low (2)
Rhondda Glyncoch Garth Avenue
Not measured Not measured Not measured 3
Low (1)
7
Low (1)
Rhondda Mountain Ash
Not measured Not measured Not measured Not measured Not measured
Rhondda Pontypridd Gelliwastad Rd
Not measured 13
Low (1)
Not measured Not measured Not measured
Rhondda-Cynon-Taf Broadway
Not measured Not measured 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 7
Low (1)
Not measured 5
Low (1)
8
Low (1)
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
Wrexham
Not measured 6
Low (1)
Not measured 3
Low (1)
5
Low (1)
Wrexham Chirk
Not measured Not measured Not measured 1
Low (1)
8
Low (1)
Wrexham Chirk Community Hospital
Not measured 0
Low (1)
Not measured 2
Low (1)
7
Low (1)