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
81
Low (3)
No Data Not measured Not measured Not measured
Bridgend Park Street
Not measured 28
Low (1)
Not measured Not measured 20
Low (2)
Caerphilly Blackwood High Street
Not measured 35
Low (1)
Not measured Not measured 14
Low (1)
Caerphilly Fochriw
Not measured Not measured Not measured 4
Low (1)
8
Low (1)
Caerphilly Islwyn Road Wattsville
Not measured 43
Low (1)
Not measured Not measured Not measured
Caerphilly White Street
Not measured 13
Low (1)
Not measured Not measured No Data
Cardiff Castle Street
Not measured 64
Low (1)
Not measured 5
Low (1)
14
Low (1)
Cardiff Centre
75
Low (3)
19
Low (1)
1
Low (1)
No Data No Data
Cardiff Newport Road
Not measured 20
Low (1)
Not measured Not measured 10
Low (1)
Chepstow A48
Not measured 46
Low (1)
Not measured 5
Low (1)
13
Low (1)
Cimla Road / Victoria Gardens
Not measured 59
Low (1)
Not measured Not measured Not measured
Cwmbran Crownbridge
66
Low (2)
7
Low (1)
Not measured Not measured 14
Low (1)
Hafod-yr-ynys Hill Roadside
Not measured 51
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 43
Low (1)
Not measured Not measured Not measured
Narberth
81
Low (3)
2
Low (1)
2
Low (1)
6
Low (1)
9
Low (1)
Newport M4 Junction 25
60
Low (2)
59
Low (1)
Not measured Not measured Not measured
Newport St Julians Comp School
Not measured 17
Low (1)
Not measured 5
Low (1)
10
Low (1)
Port Talbot Dyffryn School
Not measured Not measured Not measured No Data 20
Low (2)
Port Talbot Little Warren
Not measured Not measured Not measured 8
Low (1)
16
Low (1)
Port Talbot Margam
60
Low (2)
18
Low (1)
68
Low (1)
12
Low (2)
41
Low (3)
Port Talbot Prince Street 2
Not measured Not measured Not measured 10
Low (1)
33
Low (2)
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 5
Low (1)
9
Low (1)
Rhondda Mountain Ash
Not measured No Data Not measured Not measured Not measured
Rhondda Pontypridd Gelliwastad Rd
Not measured 68
Low (2)
Not measured Not measured Not measured
Rhondda-Cynon-Taf Broadway
Not measured 47
Low (1)
Not measured Not measured Not measured
Swansea Cwm Level Park
73
Low (3)
30
Low (1)
Not measured Not measured Not measured
Swansea Hafod DOAS
74
Low (3)
61
Low (1)
Not measured Not measured Not measured
Swansea Morfa Road NOX
Not measured 30
Low (1)
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 25
Low (1)
Not measured 9
Low (1)
Not measured
Swansea Roadside
Not measured 11
Low (1)
Not measured 5
Low (1)
14
Low (1)
Swansea St Thomas DOAS
89
Low (3)
29
Low (1)
5
Low (1)
Not measured Not measured
Swansea Station Court High Street
Not measured 65
Low (1)
Not measured Not measured Not measured
Twynyrodyn
Not measured Not measured Not measured No Data No Data
Wrexham
Not measured 20
Low (1)
2
Low (1)
3
Low (1)
7
Low (1)
Wrexham Chirk
Not measured 20
Low (1)
Not measured 6
Low (1)
14
Low (1)
Wrexham Chirk Community Hospital
Not measured 10
Low (1)
Not measured 8
Low (1)
13
Low (1)