Uncertain · Medium attention
2025 monitoring shows different nitrogen dioxide levels by location. Read the named-station values and annual report.
Annual mean nitrogen dioxide at Gatcombe Park urban background monitor; not a citywide average.
Source: Portsmouth City Council · 2025
Checked 3 October 2026
A measured concentration at this monitoring station, not a citywide average. Gatcombe Park is the urban-background station; other stations represent roadside or kerbside conditions.
Bus journeys taken across Portsmouth each year. Portsmouth local authority.
Source: DfT · year to March 2025
Checked 23 September 2026
| Year | Portsmouth | England |
|---|---|---|
| 2010 | 52.6 | 88.4 |
| 2014 | 50.1 | 86.7 |
| 2018 | 54.9 | 78.2 |
| 2019 | 52.1 | 77.1 |
| 2020 | 47.0 | 72.5 |
| 2021 | 18.8 | 28.1 |
| 2022 | 37.5 | 50.2 |
| 2023 | 45.0 | 59.3 |
| 2024 | 53.8 | 62.6 |
| 2025 | 55.6 | 62.6 |
Monitoring sites represent particular locations. The 2026 annual status report records differing trends across sites; the figures here do not establish the effect of the Clean Air Zone. See the evidence explorer for all six continuous monitoring sites.
Not published: The named monitoring sites do not measure every street or establish the causal effect of the Clean Air Zone.
Overview checked 3 October 2026. Additional figures have their own dates in the evidence explorer. Further context on UK Stat Pack.
10.77%
% · June 2026
Includes every mapped likelihood band, including very low. Denominator is all NRD 2023 properties in the local authority, including non-residential properties. Modelled risk with defences; not a prediction that this percentage will flood.
27.97 µg/m³
µg/m³ · 2025 · London Road automatic monitoring station
A measured concentration at this monitoring station, not a citywide average. Gatcombe Park is the urban-background station; other stations represent roadside or kerbside conditions.
19.08 µg/m³
µg/m³ · 2025 · London Road automatic monitoring station
A measured concentration at this monitoring station, not a citywide average. Gatcombe Park is the urban-background station; other stations represent roadside or kerbside conditions.
11.61 µg/m³
µg/m³ · 2025 · London Road automatic monitoring station
A measured concentration at this monitoring station, not a citywide average. Gatcombe Park is the urban-background station; other stations represent roadside or kerbside conditions.
14.93 µg/m³
µg/m³ · 2025 · Gatcombe Park automatic monitoring station
A measured concentration at this monitoring station, not a citywide average. Gatcombe Park is the urban-background station; other stations represent roadside or kerbside conditions.
13.91 µg/m³
µg/m³ · 2025 · Gatcombe Park automatic monitoring station
A measured concentration at this monitoring station, not a citywide average. Gatcombe Park is the urban-background station; other stations represent roadside or kerbside conditions.