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)
18
Low (2)
Anglesey Llynfaes
Not measured Not measured Not measured 7
Low (1)
15
Low (1)
Anglesey Penhesgyn 3
Not measured Not measured Not measured 7
Low (1)
14
Low (1)
Aston Hill
111
Moderate (4)
13
Low (1)
Not measured Not measured Not measured
Bridgend Park Street
Not measured 74
Low (2)
Not measured Not measured 25
Low (2)
Caerphilly Blackwood High Street
Not measured 72
Low (2)
Not measured Not measured 33
Low (2)
Caerphilly Fochriw
Not measured Not measured Not measured 17
Low (2)
25
Low (2)
Caerphilly Islwyn Road Wattsville
Not measured 37
Low (1)
Not measured Not measured Not measured
Caerphilly White Street
Not measured 95
Low (2)
Not measured Not measured 25
Low (2)
Cardiff Castle Street
Not measured 70
Low (2)
Not measured 19
Low (2)
32
Low (2)
Cardiff Centre
105
Moderate (4)
50
Low (1)
13
Low (1)
19
Low (2)
26
Low (2)
Cardiff Newport Road
Not measured 75
Low (2)
Not measured Not measured 34
Low (3)
Chepstow A48
Not measured 66
Low (1)
Not measured 21
Low (2)
30
Low (2)
Cimla Road / Victoria Gardens
Not measured 63
Low (1)
Not measured Not measured Not measured
Cwmbran Crownbridge
112
Moderate (4)
28
Low (1)
Not measured Not measured 23
Low (2)
Hafod-yr-ynys Roadside
Not measured 137
Low (3)
Not measured Not measured Not measured
Marchlyn Mawr
109
Moderate (4)
9
Low (1)
Not measured Not measured Not measured
Nantgarw Road
Not measured 49
Low (1)
Not measured Not measured Not measured
Narberth
110
Moderate (4)
10
Low (1)
9
Low (1)
17
Low (2)
23
Low (2)
Newport M4 Junction 25
68
Low (3)
70
Low (2)
Not measured Not measured Not measured
Newport St Julians Comp School
Not measured 30
Low (1)
Not measured 16
Low (2)
28
Low (2)
Port Talbot Dyffryn School
Not measured Not measured Not measured Not measured 41
Low (3)
Port Talbot Little Warren
Not measured Not measured Not measured Not measured 32
Low (2)
Port Talbot Margam
86
Low (3)
49
Low (1)
127
Low (2)
24
Low (3)
63
Moderate (5)
Port Talbot Prince Street 2
Not measured Not measured Not measured 24
Low (3)
53
Moderate (4)
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 27
Low (2)
Rhondda Mountain Ash
Not measured 75
Low (2)
Not measured Not measured Not measured
Rhondda Pontypridd Gelliwastad Rd
Not measured 75
Low (2)
Not measured Not measured Not measured
Rhondda-Cynon-Taf Broadway
Not measured 53
Low (1)
Not measured Not measured Not measured
Swansea Cwm Level Park
No Data 48
Low (1)
Not measured Not measured Not measured
Swansea Hafod DOAS
71
Low (3)
81
Low (2)
Not measured Not measured Not measured
Swansea Morfa Road NOX
Not measured 97
Low (2)
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 80
Low (2)
Not measured 21
Low (2)
Not measured
Swansea Roadside
Not measured 58
Low (1)
Not measured 22
Low (2)
35
Low (3)
Swansea St Thomas DOAS
84
Low (3)
93
Low (2)
36
Low (1)
Not measured Not measured
Swansea Station Court High Street
Not measured 106
Low (2)
Not measured Not measured Not measured
Twynyrodyn
Not measured Not measured Not measured Not measured Not measured
Wrexham
Not measured 84
Low (2)
5
Low (1)
21
Low (2)
31
Low (2)
Wrexham Chirk
Not measured 96
Low (2)
Not measured 4
Low (1)
15
Low (1)