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
118
Moderate (4)
10
Low (1)
Not measured Not measured Not measured
Bridgend Park Street
Not measured 20
Low (1)
Not measured Not measured 21
Low (2)
Caerphilly Blackwood High Street
Not measured 22
Low (1)
Not measured Not measured 21
Low (2)
Caerphilly Fochriw
Not measured Not measured Not measured 13
Low (2)
22
Low (2)
Caerphilly Islwyn Road Wattsville
Not measured 16
Low (1)
Not measured Not measured Not measured
Caerphilly White Street
Not measured 34
Low (1)
Not measured Not measured 16
Low (1)
Cardiff Castle Street
Not measured 82
Low (2)
Not measured 13
Low (2)
28
Low (2)
Cardiff Centre
119
Moderate (4)
18
Low (1)
2
Low (1)
13
Low (2)
24
Low (2)
Cardiff Newport Road
Not measured 47
Low (1)
Not measured Not measured 25
Low (2)
Chepstow A48
Not measured 27
Low (1)
Not measured 11
Low (1)
24
Low (2)
Cimla Road / Victoria Gardens
Not measured No Data Not measured Not measured Not measured
Cwmbran Crownbridge
120
Moderate (4)
19
Low (1)
Not measured Not measured 28
Low (2)
Hafod-yr-ynys Hill Roadside
Not measured 43
Low (1)
Not measured Not measured Not measured
Marchlyn Mawr
No Data 5
Low (1)
Not measured Not measured Not measured
Nantgarw Road
Not measured 15
Low (1)
Not measured Not measured Not measured
Narberth
98
Low (3)
7
Low (1)
2
Low (1)
10
Low (1)
16
Low (1)
Newport M4 Junction 25
101
Moderate (4)
131
Low (2)
Not measured Not measured Not measured
Newport St Julians Comp School
Not measured 28
Low (1)
Not measured 12
Low (2)
25
Low (2)
Port Talbot Dyffryn School
Not measured Not measured Not measured 17
Low (2)
29
Low (2)
Port Talbot Little Warren
Not measured Not measured Not measured 13
Low (2)
20
Low (2)
Port Talbot Margam
107
Moderate (4)
23
Low (1)
78
Low (1)
15
Low (2)
37
Low (3)
Port Talbot Prince Street 2
Not measured Not measured Not measured 11
Low (1)
34
Low (3)
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)
21
Low (2)
Rhondda Mountain Ash
Not measured 46
Low (1)
Not measured Not measured Not measured
Rhondda Pontypridd Gelliwastad Rd
Not measured 21
Low (1)
Not measured Not measured Not measured
Rhondda-Cynon-Taf Broadway
Not measured 30
Low (1)
Not measured Not measured Not measured
Swansea Cwm Level Park
104
Moderate (4)
21
Low (1)
Not measured Not measured Not measured
Swansea Hafod DOAS
66
Low (2)
68
Low (2)
Not measured Not measured Not measured
Swansea Morfa Road NOX
Not measured 85
Low (2)
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 53
Low (1)
Not measured 15
Low (2)
23
Low (2)
Swansea St Thomas DOAS
118
Moderate (4)
38
Low (1)
8
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 17
Low (1)
9
Low (1)
10
Low (1)
18
Low (2)
Wrexham Chirk
Not measured 18
Low (1)
Not measured 3
Low (1)
18
Low (2)
Wrexham Chirk Community Hospital
Not measured 15
Low (1)
Not measured 4
Low (1)
19
Low (2)