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
80
Low (3)
3
Low (1)
Not measured Not measured Not measured
Bridgend Park Street
Not measured 56
Low (1)
Not measured Not measured No Data
Caerphilly Blackwood High Street
Not measured 64
Low (1)
Not measured Not measured 20
Low (2)
Caerphilly Fochriw
Not measured Not measured Not measured 7
Low (1)
12
Low (1)
Caerphilly Islwyn Road Wattsville
Not measured 55
Low (1)
Not measured Not measured Not measured
Caerphilly White Street
Not measured 67
Low (1)
Not measured Not measured 33
Low (2)
Cardiff Castle Street
Not measured 83
Low (2)
Not measured 12
Low (2)
29
Low (2)
Cardiff Centre
79
Low (3)
44
Low (1)
4
Low (1)
12
Low (2)
25
Low (2)
Cardiff Newport Road
Not measured 47
Low (1)
Not measured Not measured 26
Low (2)
Chepstow A48
Not measured 87
Low (2)
Not measured 8
Low (1)
21
Low (2)
Cimla Road / Victoria Gardens
Not measured 42
Low (1)
Not measured Not measured Not measured
Cwmbran Crownbridge
66
Low (2)
46
Low (1)
Not measured Not measured 27
Low (2)
Hafod-yr-ynys Hill Roadside
Not measured 55
Low (1)
Not measured Not measured Not measured
Marchlyn Mawr
No Data 1
Low (1)
Not measured Not measured Not measured
Nantgarw Road
Not measured 68
Low (2)
Not measured Not measured Not measured
Narberth
95
Low (3)
3
Low (1)
4
Low (1)
11
Low (1)
19
Low (2)
Newport M4 Junction 25
64
Low (2)
101
Low (2)
Not measured Not measured Not measured
Newport St Julians Comp School
Not measured 46
Low (1)
Not measured 11
Low (1)
23
Low (2)
Port Talbot Dyffryn School
Not measured Not measured Not measured 16
Low (2)
37
Low (3)
Port Talbot Little Warren
Not measured Not measured Not measured No Data No Data
Port Talbot Margam
82
Low (3)
22
Low (1)
6
Low (1)
11
Low (1)
43
Low (3)
Port Talbot Prince Street 2
Not measured Not measured Not measured 19
Low (2)
58
Moderate (4)
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 No Data No Data
Rhondda Mountain Ash
Not measured 90
Low (2)
Not measured Not measured Not measured
Rhondda Pontypridd Gelliwastad Rd
Not measured 120
Low (2)
Not measured Not measured Not measured
Rhondda-Cynon-Taf Broadway
Not measured 58
Low (1)
Not measured Not measured Not measured
Swansea Cwm Level Park
71
Low (3)
30
Low (1)
Not measured Not measured Not measured
Swansea Hafod DOAS
76
Low (3)
115
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 No Data Not measured No Data Not measured
Swansea Roadside
Not measured 57
Low (1)
Not measured 11
Low (1)
32
Low (2)
Swansea St Thomas DOAS
73
Low (3)
58
Low (1)
19
Low (1)
Not measured Not measured
Swansea Station Court High Street
Not measured 78
Low (2)
Not measured Not measured Not measured
Twynyrodyn
Not measured Not measured Not measured No Data No Data
Wrexham
Not measured 68
Low (2)
9
Low (1)
6
Low (1)
11
Low (1)
Wrexham Chirk
Not measured 70
Low (2)
Not measured 10
Low (1)
22
Low (2)
Wrexham Chirk Community Hospital
Not measured 78
Low (2)
Not measured 13
Low (2)
20
Low (2)