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
90
Low (3)
3
Low (1)
Not measured Not measured Not measured
Bridgend Park Street
Not measured 62
Low (1)
Not measured Not measured 11
Low (1)
Caerphilly Blackwood High Street
Not measured 41
Low (1)
Not measured Not measured 9
Low (1)
Caerphilly Fochriw
Not measured Not measured Not measured 5
Low (1)
7
Low (1)
Caerphilly Islwyn Road Wattsville
Not measured 44
Low (1)
Not measured Not measured Not measured
Caerphilly White Street
Not measured 50
Low (1)
Not measured Not measured 6
Low (1)
Cardiff Castle Street
Not measured 79
Low (2)
Not measured 6
Low (1)
14
Low (1)
Cardiff Centre
92
Low (3)
28
Low (1)
1
Low (1)
6
Low (1)
12
Low (1)
Cardiff Newport Road
Not measured 48
Low (1)
Not measured Not measured 12
Low (1)
Chepstow A48
Not measured 45
Low (1)
Not measured 6
Low (1)
14
Low (1)
Cimla Road / Victoria Gardens
Not measured 83
Low (2)
Not measured Not measured Not measured
Cwmbran Crownbridge
84
Low (3)
15
Low (1)
Not measured Not measured 10
Low (1)
Hafod-yr-ynys Hill Roadside
Not measured 50
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 57
Low (1)
Not measured Not measured Not measured
Narberth
99
Low (3)
12
Low (1)
1
Low (1)
3
Low (1)
6
Low (1)
Newport M4 Junction 25
58
Low (2)
95
Low (2)
Not measured Not measured Not measured
Newport St Julians Comp School
Not measured 26
Low (1)
Not measured 4
Low (1)
8
Low (1)
Port Talbot Dyffryn School
Not measured Not measured Not measured 6
Low (1)
6
Low (1)
Port Talbot Little Warren
Not measured Not measured Not measured 12
Low (2)
30
Low (2)
Port Talbot Margam
96
Low (3)
25
Low (1)
3
Low (1)
5
Low (1)
10
Low (1)
Port Talbot Prince Street 2
Not measured Not measured Not measured 4
Low (1)
9
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 11
Low (1)
72
Moderate (6)
Rhondda Mountain Ash
Not measured 104
Low (2)
Not measured Not measured Not measured
Rhondda Pontypridd Gelliwastad Rd
Not measured 75
Low (2)
Not measured Not measured Not measured
Rhondda-Cynon-Taf Broadway
Not measured 55
Low (1)
Not measured Not measured Not measured
Swansea Cwm Level Park
79
Low (3)
No Data Not measured Not measured Not measured
Swansea Hafod DOAS
69
Low (3)
113
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 59
Low (1)
Not measured 11
Low (1)
Not measured
Swansea Roadside
Not measured 52
Low (1)
Not measured 5
Low (1)
13
Low (1)
Swansea St Thomas DOAS
83
Low (3)
40
Low (1)
16
Low (1)
Not measured Not measured
Swansea Station Court High Street
Not measured 70
Low (2)
Not measured Not measured Not measured
Twynyrodyn
Not measured Not measured Not measured No Data No Data
Wrexham
Not measured 28
Low (1)
3
Low (1)
3
Low (1)
7
Low (1)
Wrexham Chirk
Not measured 21
Low (1)
Not measured 3
Low (1)
12
Low (1)
Wrexham Chirk Community Hospital
Not measured 15
Low (1)
Not measured 4
Low (1)
11
Low (1)