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 2
Low (1)
9
Low (1)
Anglesey Llynfaes
Not measured Not measured Not measured 2
Low (1)
11
Low (1)
Anglesey Penhesgyn 3
Not measured Not measured Not measured 2
Low (1)
9
Low (1)
Aston Hill
60
Low (2)
3
Low (1)
Not measured Not measured Not measured
Caerphilly Blackwood High Street
Not measured 20
Low (1)
Not measured Not measured 7
Low (1)
Caerphilly Fochriw
Not measured Not measured Not measured Not measured Not measured
Caerphilly Islwyn Road Wattsville
Not measured 12
Low (1)
Not measured Not measured Not measured
Caerphilly White Street
Not measured 28
Low (1)
Not measured Not measured 11
Low (1)
Cardiff Centre
50
Low (2)
26
Low (1)
No Data No Data No Data
Cardiff Newport Road
Not measured 23
Low (1)
Not measured Not measured No Data
Chepstow A48
Not measured 36
Low (1)
Not measured 4
Low (1)
8
Low (1)
Cimla Road / Victoria Gardens
Not measured 35
Low (1)
Not measured Not measured Not measured
Cwmbran
56
Low (2)
6
Low (1)
Not measured Not measured 9
Low (1)
Hafod-yr-ynys Roadside
Not measured 73
Low (2)
Not measured Not measured Not measured
Marchlyn Mawr
62
Low (2)
2
Low (1)
Not measured Not measured Not measured
Nantgarw Road
Not measured 26
Low (1)
Not measured Not measured Not measured
Narberth
47
Low (2)
3
Low (1)
2
Low (1)
2
Low (1)
4
Low (1)
Newport M4 Junction 25
36
Low (2)
35
Low (1)
Not measured Not measured Not measured
Newport St Julians Comp School
Not measured 25
Low (1)
Not measured 4
Low (1)
7
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 11
Low (1)
Port Talbot Margam
41
Low (2)
13
Low (1)
17
Low (1)
No Data No Data
Port Talbot Prince Street 2
Not measured Not measured Not measured 9
Low (1)
32
Low (2)
Port Talbot Twll-yn-y-Wal Park
Not measured Not measured Not measured Not measured 1
Low (1)
Rhondda Glyncoch Garth Avenue
Not measured Not measured Not measured Not measured 11
Low (1)
Rhondda Mountain Ash
Not measured 40
Low (1)
Not measured Not measured Not measured
Rhondda Pontypridd Gelliwastad Rd
Not measured 31
Low (1)
Not measured Not measured Not measured
Rhondda-Cynon-Taf Broadway
Not measured 35
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 30
Low (1)
Not measured No Data No Data
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
V Glamorgan Windsor Road Penarth
40
Low (2)
26
Low (1)
Not measured Not measured 14
Low (1)
Wrexham
Not measured 16
Low (1)
4
Low (1)
2
Low (1)
5
Low (1)