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 11
Low (1)
17
Low (2)
Anglesey Llynfaes
Not measured Not measured Not measured 7
Low (1)
23
Low (2)
Anglesey Penhesgyn 3
Not measured Not measured Not measured 7
Low (1)
10
Low (1)
Aston Hill
74
Low (3)
2
Low (1)
Not measured Not measured Not measured
Bridgend Park Street
Not measured Not measured Not measured Not measured Not measured
Caerphilly Blackwood High Street
Not measured 54
Low (1)
Not measured Not measured 9
Low (1)
Caerphilly Fochriw
Not measured Not measured Not measured 4
Low (1)
No Data
Caerphilly Islwyn Road Wattsville
Not measured 39
Low (1)
Not measured Not measured Not measured
Caerphilly White Street
Not measured 37
Low (1)
Not measured Not measured 8
Low (1)
Cardiff Castle Street
Not measured 43
Low (1)
Not measured 3
Low (1)
10
Low (1)
Cardiff Centre
73
Low (3)
25
Low (1)
2
Low (1)
5
Low (1)
7
Low (1)
Cardiff Newport Road
Not measured 33
Low (1)
Not measured Not measured 11
Low (1)
Chepstow A48
Not measured 68
Low (2)
Not measured 4
Low (1)
11
Low (1)
Cimla Road / Victoria Gardens
Not measured 77
Low (2)
Not measured Not measured Not measured
Cwmbran Crownbridge
80
Low (3)
15
Low (1)
Not measured Not measured 8
Low (1)
Hafod-yr-ynys Roadside
Not measured 90
Low (2)
Not measured Not measured Not measured
Marchlyn Mawr
73
Low (3)
2
Low (1)
Not measured Not measured Not measured
Nantgarw Road
Not measured 33
Low (1)
Not measured Not measured Not measured
Narberth
75
Low (3)
2
Low (1)
5
Low (1)
4
Low (1)
8
Low (1)
Newport M4 Junction 25
Not measured Not measured Not measured Not measured Not measured
Newport St Julians Comp School
Not measured 20
Low (1)
Not measured 2
Low (1)
4
Low (1)
Port Talbot Dyffryn School
Not measured Not measured Not measured Not measured Not measured
Port Talbot Little Warren
Not measured Not measured Not measured Not measured 18
Low (2)
Port Talbot Margam
64
Low (2)
20
Low (1)
2
Low (1)
3
Low (1)
9
Low (1)
Port Talbot Prince Street 2
Not measured Not measured Not measured 6
Low (1)
16
Low (1)
Port Talbot Twll-yn-y-Wal Park
Not measured Not measured Not measured Not measured Not measured
Rhondda Glyncoch Garth Avenue
Not measured Not measured Not measured Not measured 6
Low (1)
Rhondda Mountain Ash
Not measured 60
Low (1)
Not measured Not measured Not measured
Rhondda Pontypridd Gelliwastad Rd
Not measured 61
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
Not measured Not measured Not measured Not measured Not measured
Swansea Hafod DOAS
81
Low (3)
55
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 49
Low (1)
Not measured 6
Low (1)
Not measured
Swansea Roadside
Not measured 38
Low (1)
Not measured 6
Low (1)
10
Low (1)
Swansea St Thomas DOAS
Not measured Not measured Not measured 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
Wrexham
Not measured 50
Low (1)
2
Low (1)
4
Low (1)
7
Low (1)
Wrexham Chirk
Not measured 52
Low (1)
Not measured 4
Low (1)
9
Low (1)