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 9
Low (1)
17
Low (2)
Anglesey Llynfaes
Not measured Not measured Not measured Not measured Not measured
Anglesey Penhesgyn 3
Not measured Not measured Not measured Not measured Not measured
Aston Hill
67
Low (3)
1
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 26
Low (1)
Not measured Not measured 17
Low (2)
Caerphilly Fochriw
Not measured Not measured Not measured 5
Low (1)
11
Low (1)
Caerphilly Islwyn Road Wattsville
Not measured 31
Low (1)
Not measured Not measured Not measured
Caerphilly White Street
Not measured 17
Low (1)
Not measured Not measured 16
Low (1)
Cardiff Castle Street
Not measured 44
Low (1)
Not measured 5
Low (1)
17
Low (2)
Cardiff Centre
56
Low (2)
23
Low (1)
3
Low (1)
9
Low (1)
13
Low (1)
Cardiff Newport Road
Not measured 15
Low (1)
Not measured Not measured 14
Low (1)
Chepstow A48
Not measured 36
Low (1)
Not measured 7
Low (1)
16
Low (1)
Cimla Road / Victoria Gardens
Not measured Not measured Not measured Not measured Not measured
Cwmbran Crownbridge
64
Low (2)
7
Low (1)
Not measured Not measured 13
Low (1)
Hafod-yr-ynys Roadside
Not measured 69
Low (2)
Not measured Not measured Not measured
Marchlyn Mawr
62
Low (2)
1
Low (1)
Not measured Not measured Not measured
Nantgarw Road
Not measured 32
Low (1)
Not measured Not measured Not measured
Narberth
59
Low (2)
2
Low (1)
1
Low (1)
5
Low (1)
11
Low (1)
Newport M4 Junction 25
49
Low (2)
No Data Not measured Not measured Not measured
Newport St Julians Comp School
Not measured 13
Low (1)
Not measured 4
Low (1)
10
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 5
Low (1)
17
Low (2)
Port Talbot Margam
50
Low (2)
33
Low (1)
51
Low (1)
8
Low (1)
38
Low (3)
Port Talbot Prince Street 2
Not measured Not measured Not measured 9
Low (1)
37
Low (3)
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 10
Low (1)
Rhondda Mountain Ash
Not measured Not measured Not measured Not measured Not measured
Rhondda Pontypridd Gelliwastad Rd
Not measured 14
Low (1)
Not measured Not measured Not measured
Rhondda-Cynon-Taf Broadway
Not measured 29
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
Not measured Not measured 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 Not measured Not measured Not measured Not measured
Swansea Roadside
Not measured 16
Low (1)
Not measured 7
Low (1)
15
Low (1)
Swansea St Thomas DOAS
51
Low (2)
31
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
Wrexham
Not measured 12
Low (1)
2
Low (1)
3
Low (1)
6
Low (1)
Wrexham Chirk
Not measured 24
Low (1)
Not measured 3
Low (1)
13
Low (1)
Wrexham Chirk Community Hospital
Not measured 22
Low (1)
Not measured 5
Low (1)
13
Low (1)