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 14
Low (2)
23
Low (2)
Anglesey Felin Cafnan
Not measured Not measured Not measured 16
Low (2)
35
Low (3)
Anglesey Llynfaes
Not measured Not measured Not measured 17
Low (2)
27
Low (2)
Anglesey Penhesgyn 3
Not measured Not measured Not measured 16
Low (2)
25
Low (2)
Aston Hill
94
Low (3)
2
Low (1)
Not measured Not measured Not measured
Caerphilly Blackwood High Street
Not measured 37
Low (1)
Not measured Not measured 13
Low (1)
Caerphilly Fochriw
Not measured Not measured Not measured 6
Low (1)
10
Low (1)
Caerphilly Islwyn Road Wattsville
Not measured 46
Low (1)
Not measured Not measured Not measured
Caerphilly White Street
Not measured 54
Low (1)
Not measured Not measured 15
Low (1)
Cardiff Centre
72
Low (3)
36
Low (1)
3
Low (1)
13
Low (2)
22
Low (2)
Cardiff Newport Road
Not measured 52
Low (1)
Not measured Not measured 20
Low (2)
Chepstow A48
Not measured 68
Low (2)
Not measured 10
Low (1)
19
Low (2)
Cimla Road / Victoria Gardens
Not measured 37
Low (1)
Not measured Not measured Not measured
Cwmbran
85
Low (3)
23
Low (1)
Not measured Not measured 19
Low (2)
Hafod-yr-ynys Roadside
Not measured 206
Moderate (4)
Not measured Not measured Not measured
Marchlyn Mawr
No Data No Data Not measured Not measured Not measured
Nantgarw Road
Not measured 34
Low (1)
Not measured Not measured Not measured
Narberth
66
Low (2)
7
Low (1)
4
Low (1)
6
Low (1)
13
Low (1)
Newport M4 Junction 25
47
Low (2)
67
Low (1)
Not measured Not measured Not measured
Newport St Julians Comp School
Not measured 41
Low (1)
Not measured 7
Low (1)
14
Low (1)
Port Talbot Dyffryn School
Not measured Not measured Not measured Not measured 15
Low (1)
Port Talbot Little Warren
Not measured Not measured Not measured Not measured 15
Low (1)
Port Talbot Margam
84
Low (3)
27
Low (1)
1
Low (1)
9
Low (1)
14
Low (1)
Port Talbot Prince Street 2
Not measured Not measured Not measured 8
Low (1)
12
Low (1)
Port Talbot Twll-yn-y-Wal Park
Not measured Not measured Not measured Not measured 15
Low (1)
Rhondda Glyncoch Garth Avenue
Not measured Not measured Not measured Not measured No Data
Rhondda Mountain Ash
Not measured 78
Low (2)
Not measured Not measured Not measured
Rhondda Pontypridd Gelliwastad Rd
Not measured 44
Low (1)
Not measured Not measured Not measured
Rhondda-Cynon-Taf Broadway
Not measured 48
Low (1)
Not measured Not measured Not measured
Swansea Cwm Level Park
88
Low (3)
14
Low (1)
Not measured Not measured Not measured
Swansea Hafod DOAS
85
Low (3)
48
Low (1)
Not measured Not measured Not measured
Swansea Morfa Road NOX
Not measured 28
Low (1)
Not measured Not measured Not measured
Swansea Morriston Roadside
No Data No Data Not measured No Data Not measured
Swansea Roadside
Not measured 29
Low (1)
Not measured 7
Low (1)
14
Low (1)
Swansea St Thomas DOAS
95
Low (3)
64
Low (1)
4
Low (1)
Not measured Not measured
Swansea Station Court High Street
Not measured 81
Low (2)
Not measured Not measured Not measured
Twynyrodyn
Not measured Not measured Not measured No Data No Data
V Glamorgan Windsor Road Penarth
60
Low (2)
59
Low (1)
Not measured Not measured 15
Low (1)
Wrexham
Not measured 18
Low (1)
2
Low (1)
6
Low (1)
12
Low (1)