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
74
Low (3)
3
Low (1)
Not measured Not measured Not measured
Bridgend Park Street
Not measured 29
Low (1)
Not measured Not measured No Data
Caerphilly Blackwood High Street
Not measured 31
Low (1)
Not measured Not measured No Data
Caerphilly Fochriw
Not measured Not measured Not measured No Data No Data
Caerphilly Islwyn Road Wattsville
Not measured 21
Low (1)
Not measured Not measured Not measured
Caerphilly White Street
Not measured 26
Low (1)
Not measured Not measured No Data
Cardiff Castle Street
Not measured 54
Low (1)
Not measured No Data No Data
Cardiff Centre
65
Low (2)
43
Low (1)
4
Low (1)
11
Low (1)
11
Low (1)
Cardiff Newport Road
Not measured 56
Low (1)
Not measured Not measured 13
Low (1)
Chepstow A48
Not measured 76
Low (2)
Not measured No Data 10
Low (1)
Cimla Road / Victoria Gardens
Not measured 49
Low (1)
Not measured Not measured Not measured
Cwmbran Crownbridge
57
Low (2)
28
Low (1)
Not measured Not measured No Data
Hafod-yr-ynys Hill Roadside
Not measured 66
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 No Data Not measured Not measured Not measured
Narberth
70
Low (3)
5
Low (1)
2
Low (1)
2
Low (1)
5
Low (1)
Newport M4 Junction 25
No Data 69
Low (2)
Not measured Not measured Not measured
Newport St Julians Comp School
Not measured 46
Low (1)
Not measured 8
Low (1)
10
Low (1)
Port Talbot Dyffryn School
Not measured Not measured Not measured No Data No Data
Port Talbot Little Warren
Not measured Not measured Not measured No Data No Data
Port Talbot Margam
66
Low (2)
36
Low (1)
46
Low (1)
5
Low (1)
9
Low (1)
Port Talbot Prince Street 2
Not measured Not measured Not measured No Data No Data
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 No Data Not measured Not measured Not measured
Rhondda Pontypridd Gelliwastad Rd
Not measured 50
Low (1)
Not measured Not measured Not measured
Rhondda-Cynon-Taf Broadway
Not measured No Data Not measured Not measured Not measured
Swansea Cwm Level Park
No Data No Data Not measured Not measured Not measured
Swansea Hafod DOAS
51
Low (2)
116
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 68
Low (2)
Not measured 6
Low (1)
9
Low (1)
Swansea St Thomas DOAS
53
Low (2)
80
Low (2)
7
Low (1)
Not measured Not measured
Swansea Station Court High Street
Not measured No Data Not measured Not measured Not measured
Twynyrodyn
Not measured Not measured Not measured No Data No Data
Wrexham
Not measured 30
Low (1)
5
Low (1)
8
Low (1)
10
Low (1)
Wrexham Chirk
Not measured 16
Low (1)
Not measured No Data No Data
Wrexham Chirk Community Hospital
Not measured No Data Not measured No Data No Data