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
Anglesey Brynteg
Not measured Not measured Not measured 8
Low (1)
16
Low (1)
Anglesey Llynfaes
Not measured Not measured Not measured 8
Low (1)
14
Low (1)
Anglesey Penhesgyn 3
Not measured Not measured Not measured 7
Low (1)
11
Low (1)
Aston Hill
91
Low (3)
11
Low (1)
Not measured Not measured Not measured
Caerphilly Blackwood High Street
Not measured 8
Low (1)
Not measured Not measured 33
Low (2)
Caerphilly Fochriw
Not measured Not measured Not measured 13
Low (2)
21
Low (2)
Caerphilly Islwyn Road Wattsville
Not measured 12
Low (1)
Not measured Not measured Not measured
Caerphilly White Street
Not measured 11
Low (1)
Not measured Not measured 34
Low (3)
Cardiff Centre
97
Low (3)
2
Low (1)
2
Low (1)
12
Low (2)
20
Low (2)
Cardiff Newport Road
Not measured 18
Low (1)
Not measured Not measured 25
Low (2)
Chepstow A48
Not measured 8
Low (1)
Not measured 18
Low (2)
27
Low (2)
Cimla Road / Victoria Gardens
Not measured 48
Low (1)
Not measured Not measured Not measured
Cwmbran
96
Low (3)
8
Low (1)
Not measured Not measured 21
Low (2)
Hafod-yr-ynys Roadside
Not measured 26
Low (1)
Not measured Not measured Not measured
Marchlyn Mawr
106
Moderate (4)
4
Low (1)
Not measured Not measured Not measured
Nantgarw Road
Not measured 12
Low (1)
Not measured Not measured Not measured
Narberth
76
Low (3)
8
Low (1)
3
Low (1)
11
Low (1)
15
Low (1)
Newport M4 Junction 25
87
Low (3)
9
Low (1)
Not measured Not measured Not measured
Newport St Julians Comp School
Not measured 13
Low (1)
Not measured 16
Low (2)
22
Low (2)
Port Talbot Dyffryn School
Not measured Not measured Not measured Not measured 31
Low (2)
Port Talbot Little Warren
Not measured Not measured Not measured Not measured 20
Low (2)
Port Talbot Margam
94
Low (3)
14
Low (1)
1
Low (1)
10
Low (1)
19
Low (2)
Port Talbot Prince Street 2
Not measured Not measured Not measured 11
Low (1)
18
Low (2)
Port Talbot Twll-yn-y-Wal Park
Not measured Not measured Not measured Not measured 17
Low (2)
Rhondda Glyncoch Garth Avenue
Not measured Not measured Not measured Not measured 19
Low (2)
Rhondda Mountain Ash
Not measured Not measured Not measured Not measured Not measured
Rhondda Pontypridd Gelliwastad Rd
Not measured 55
Low (1)
Not measured Not measured Not measured
Rhondda-Cynon-Taf Broadway
Not measured 24
Low (1)
Not measured Not measured Not measured
Swansea Cwm Level Park
Not measured Not measured Not measured Not measured Not measured
Swansea Hafod DOAS
93
Low (3)
20
Low (1)
Not measured Not measured Not measured
Swansea Morfa Road NOX
Not measured Not measured Not measured Not measured Not measured
Swansea Morriston Roadside
Not measured Not measured Not measured Not measured Not measured
Swansea Port Tennant Roadside
Not measured 14
Low (1)
Not measured 11
Low (1)
Not measured
Swansea Roadside
Not measured 4
Low (1)
Not measured No Data 20
Low (2)
Swansea St Thomas DOAS
96
Low (3)
23
Low (1)
6
Low (1)
Not measured Not measured
Swansea Station Court High Street
Not measured Not measured Not measured Not measured Not measured
Twynyrodyn
Not measured Not measured Not measured Not measured Not measured
V Glamorgan Windsor Road Penarth
86
Low (3)
21
Low (1)
Not measured Not measured 22
Low (2)
Wrexham
Not measured 19
Low (1)
14
Low (1)
12
Low (2)
19
Low (2)