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
86
Low (3)
4
Low (1)
Not measured Not measured Not measured
Bridgend Park Street
Not measured 59
Low (1)
Not measured Not measured 12
Low (1)
Caerphilly Blackwood High Street
Not measured 28
Low (1)
Not measured Not measured 8
Low (1)
Caerphilly Fochriw
Not measured Not measured Not measured 4
Low (1)
6
Low (1)
Caerphilly Islwyn Road Wattsville
Not measured 40
Low (1)
Not measured Not measured Not measured
Caerphilly White Street
Not measured 72
Low (2)
Not measured Not measured 7
Low (1)
Cardiff Castle Street
Not measured 40
Low (1)
Not measured 4
Low (1)
9
Low (1)
Cardiff Centre
82
Low (3)
23
Low (1)
2
Low (1)
6
Low (1)
7
Low (1)
Cardiff Newport Road
Not measured 38
Low (1)
Not measured Not measured 11
Low (1)
Chepstow A48
Not measured 33
Low (1)
Not measured 4
Low (1)
11
Low (1)
Cimla Road / Victoria Gardens
Not measured 31
Low (1)
Not measured Not measured Not measured
Cwmbran Crownbridge
No Data 18
Low (1)
Not measured Not measured 10
Low (1)
Hafod-yr-ynys Hill Roadside
Not measured 73
Low (2)
Not measured Not measured Not measured
Marchlyn Mawr
No Data 2
Low (1)
Not measured Not measured Not measured
Nantgarw Road
Not measured 30
Low (1)
Not measured Not measured Not measured
Narberth
78
Low (3)
18
Low (1)
1
Low (1)
4
Low (1)
12
Low (1)
Newport M4 Junction 25
73
Low (3)
34
Low (1)
Not measured Not measured Not measured
Newport St Julians Comp School
Not measured 40
Low (1)
Not measured 3
Low (1)
7
Low (1)
Port Talbot Dyffryn School
Not measured Not measured Not measured 6
Low (1)
7
Low (1)
Port Talbot Little Warren
Not measured Not measured Not measured 7
Low (1)
10
Low (1)
Port Talbot Margam
81
Low (3)
26
Low (1)
2
Low (1)
4
Low (1)
10
Low (1)
Port Talbot Prince Street 2
Not measured Not measured Not measured 4
Low (1)
12
Low (1)
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 3
Low (1)
6
Low (1)
Rhondda Mountain Ash
Not measured 74
Low (2)
Not measured Not measured Not measured
Rhondda Pontypridd Gelliwastad Rd
Not measured 52
Low (1)
Not measured Not measured Not measured
Rhondda-Cynon-Taf Broadway
Not measured 40
Low (1)
Not measured Not measured Not measured
Swansea Cwm Level Park
80
Low (3)
44
Low (1)
Not measured Not measured Not measured
Swansea Hafod DOAS
84
Low (3)
75
Low (2)
Not measured Not measured Not measured
Swansea Morfa Road NOX
Not measured No Data Not measured Not measured Not measured
Swansea Morriston Roadside
No Data No Data Not measured No Data Not measured
Swansea Port Tennant Roadside
Not measured 62
Low (1)
Not measured 8
Low (1)
Not measured
Swansea Roadside
Not measured 40
Low (1)
Not measured 5
Low (1)
15
Low (1)
Swansea St Thomas DOAS
80
Low (3)
74
Low (2)
5
Low (1)
Not measured Not measured
Swansea Station Court High Street
Not measured 71
Low (2)
Not measured Not measured Not measured
Twynyrodyn
Not measured Not measured Not measured No Data No Data
Wrexham
Not measured 34
Low (1)
4
Low (1)
4
Low (1)
8
Low (1)
Wrexham Chirk
Not measured 29
Low (1)
Not measured 4
Low (1)
14
Low (1)
Wrexham Chirk Community Hospital
Not measured 19
Low (1)
Not measured 6
Low (1)
13
Low (1)