1001 Smart Cities

Permanent project revision

Bristol Clean Air Zone (Class D)

Revision 2026-08-25-bristol-baseline · effective 2026-08-25

Current revision. This is the snapshot used by the live entity page.

unreviewed

Created the first structured Evidence Passport with 16 claims and 7 source dossiers.

sha256:e3ae9d8628f2d075a0723ee9067fa721686a5a2b37dce897cb3fd83ca1c7ba24
All revisions → Current entity page →

Change set

  • add /evidencePassport — Added claim-level evidence mapping and source dossiers.
  • add /revisionHistory — Established a permanent, hash-addressed baseline revision.
16
of 16 claims mapped
7
source dossiers
4
publication dates recorded
0
archives linked
0
exact locators
0
content captures hashed

Claims, one by one

The text below is copied verbatim from the published record. Each claim names the source dossiers that carry it; caveats stay attached to the claim they qualify.

Claim 1 clm-f3a0cb386db0ff2f quantitative
Charging began on 28 November 2022
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The change history on the government's Clean Air Zone guidance carries the entry 'Bristol will start charging on 28 November 2022', and a further entry dated 28 November 2022 recording that the zone 'is now in operation'.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. GOV.UK — Driving in a clean air zone (authority)
Claim 2 clm-ff098ea2dfd89943 quantitative
in a zone of 1.18 square miles around Bristol's centre
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The government's table 'Cities with Clean Air Zones' lists City, Class and Area (square miles), and gives the Bristol row as D and 1.18. The value 1.18 appears once on the page.
Caveat
The figure is the area the government publishes for the zone; the council's own pages describe the boundary by map rather than by area.

Sources carrying this claim

  1. GOV.UK — Driving in a clean air zone (authority)
Claim 3 clm-0a2cbff532aebde3 quantitative
£9 a day for a non-compliant car, taxi or van, £100 for a lorry, bus or coach
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The council's charge table gives 'Private petrol cars £9, Private diesel cars £9, Taxis £9, Light Goods Vehicle (under 3.5t.) £9, Heavy Goods Vehicle (over 3.5t.) £100, Buses £100, Coaches £100'. The charge is payable only if the vehicle does not meet the zone's emissions standards.
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Bristol City Council — Pay the Clean Air Zone daily charge (authority)
Claim 4 clm-f7603117e6eda141 quantitative
24 hours a day and every day of the year
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The council states 'Charges apply 24 hours a day, midnight to midnight, 365 days of the year.' The government guidance says the same of all English zones: 'The zones operate 24 hours a day, 7 days a week, every day of the year.'
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Bristol City Council — Pay the Clean Air Zone daily charge (authority)
  2. GOV.UK — Driving in a clean air zone (authority)
Claim 5 clm-48728df008e1385e descriptive
enforced by automatic number plate recognition cameras
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The council's exemptions page states 'The Clean Air Zone is managed by cameras with Automatic Number Plate Recognition (ANPR)', and adds that the ANPR system recognises exempt vehicles automatically.
Caveat
The council does not publish a camera count on this page. A figure of 49 cameras circulates in a supplier case study published by ITS UK on behalf of Intelliscape; it is vendor material and is deliberately not carried in this entry.

Sources carrying this claim

  1. Bristol City Council — What are Clean Air Zone Exemptions (authority)
Claim 6 clm-7e836fa729f15980 descriptive
It is a Class D zone — of England's seven Clean Air Zones, only Bristol and Birmingham charge private cars
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The government's table lists all seven English zones with their class: Bath C, Birmingham D, Bradford C, Bristol D, Portsmouth B, Sheffield C, Tyneside C. The class definitions give Class D as 'Buses, coaches, taxis, private hire vehicles, heavy goods vehicles, vans, minibuses, cars' — the only class that reaches cars. Bristol's own status report also calls it 'A Class D Clean Air Zone (CAZ)'.
Caveat
This counts only the Clean Air Zone framework. London's Ultra Low Emission Zone also charges cars but is a separate scheme run by the Mayor of London, and the same government page says so; Greater Manchester was directed to a zone that never began charging.

Sources carrying this claim

  1. GOV.UK — Driving in a clean air zone (authority)
  2. Bristol City Council — 2025 Air Quality Annual Status Report (authority)
Claim 7 clm-99b8af652e468798 descriptive
Bristol did not choose it; the Secretary of State directed it
Published field
snippet · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The Direction was made by the Secretary of State under section 85(5) of the Environment Act 1995 and requires the authority to implement its local plan for NO2 compliance. Bristol's own status report states 'Bristol City Council has been directed by the UK Government to achieve compliance with air quality objectives in the shortest possible time. A Class D Clean Air Zone (CAZ) came into operation in November 2022 in order to achieve compliance.'
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Environment Act 1995 (Bristol City Council) Air Quality Direction 2021 (Defra)
  2. Bristol City Council — 2025 Air Quality Annual Status Report (authority)
Claim 8 clm-b2e54d2a9ecc6670 quantitative
an average fall of 13.2% in annual NO2 across 191 locations between 2022 and 2023, the zone's first year
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The status report's conclusions state 'Out of the 191 NO2 monitoring locations with data for both 2022 and 2023, 176 showed a reduction in annual NO2 levels in 2023 when compared to 2022. On average, annual NO2 concentrations fell by 13.2% between 2022 and 2023.'
Caveat
The council's own figure and not an independent estimate, and the same report warns that annual concentrations 'can be impacted significantly year on year by factors such as the prevailing meteorological conditions'. It says the data suggests the zone contributed to the fall, not that it caused all of it.

Sources carrying this claim

  1. Bristol City Council — 2025 Air Quality Annual Status Report (authority)
Claim 9 clm-3d0dad9fca3b75a3 quantitative
a further 4.7% between 2023 and 2024
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The same section states 'There were 191 locations across Bristol where NO2 concentrations were measured in 2023 and 2024. At these locations, on average, NO2 concentrations fell by 4.7%.'
Caveat
The report also records that NO2 rose at 43 of the 191 locations in 2024, 19 of them by less than 1 microgram per cubic metre.

Sources carrying this claim

  1. Bristol City Council — 2025 Air Quality Annual Status Report (authority)
Claim 10 clm-b464de7a95538d85 quantitative
The Direction had required compliance by 2023 at the latest
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
Article 4(2)(a) of the Direction requires the authority to ensure the local plan is implemented so that 'compliance with the legal limit value for nitrogen dioxide is achieved in the shortest possible time, and by 2023 at the latest'. Schedule 1 gives the deadline for the Class D zone itself as 'To be implemented as soon as possible and at least in time to bring forward compliance to 2023.'
Caveat
The Direction's deadline is for the limit value that Defra assesses nationally; the council's diffusion-tube monitoring reported below is the separate Local Air Quality Management regime. The two are related but not the same test.

Sources carrying this claim

  1. Environment Act 1995 (Bristol City Council) Air Quality Direction 2021 (Defra)
Claim 11 clm-7ca4780c86be7539 quantitative
Five monitoring sites were still above the 40µg/m3 annual objective in 2024
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The conclusions state '2024 monitoring data shows that NO2 concentrations have continued to fall when compared to 2023, however, five monitoring sites were still above the legal objective for nitrogen dioxide in 2024.' The report names the objective elsewhere as 'the UK annual objective of 40µg/m3 for nitrogen dioxide' and names sites including College Green/Anchor Road at 41.0µg/m3, Old Market Roundabout at 41.6µg/m3 and Rupert Street at 45.4µg/m3.
Caveat
The report attributes some individual exceedances to non-road sources or to monitoring positions that are not places of relevant exposure, so the count is not by itself a statement that people are exposed above the limit at five locations.

Sources carrying this claim

  1. Bristol City Council — 2025 Air Quality Annual Status Report (authority)
Claim 12 clm-d70b4e120d7d5059 descriptive
the council's own progress table records the measure as "Compliance not yet achieved"
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
In the report's table of progress on measures, the row for the clean air zone measure 'Achieving Compliance within the shortest timeframe possible' carries the status text 'CAZ introduced in November 2022. For latest developments see https://www.cleanairforbristol.org/ Compliance not yet achieved. Further measures being investigated with JAQU through their Triage Process.'
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Bristol City Council — 2025 Air Quality Annual Status Report (authority)
Claim 13 clm-f5882bdac739ebd8 quantitative
Charges and penalties raised more than £26 million after operating costs in the first year
Published field
impact · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
ITV News West Country reported the council's first-year figures as more than £31 million taken, of which £4.8 million went on operation costs, leaving a £26.4 million surplus in the zone's first year.
Caveat
Council figures reported by a broadcaster, not audited independently. The page was read through a summarising fetch rather than a raw download, so the locator should be re-checked against the live page. No published revenue forecast was found to compare the outturn against.

Sources carrying this claim

  1. ITV News West Country — Clean Air Zone first-year revenue (press)
Claim 14 clm-2e3c05aa615a71a8 descriptive
the charge is set by the vehicle's Euro class, not by any reading, and no measured threshold moves it
Published field
lesson · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
The council's status report states 'The CAZ charges older vehicles based on the vehicle Euro category classification.' The published charge table gives one flat daily rate per vehicle category and no variation of any kind; neither the council's scheme pages nor the Direction provide for a rate that changes with measured air quality.
Caveat
The second half is an absence: no source consulted describes an air-quality-triggered variation, which is weaker evidence than a source stating there is none.

Sources carrying this claim

  1. Bristol City Council — 2025 Air Quality Annual Status Report (authority)
  2. Bristol City Council — Pay the Clean Air Zone daily charge (authority)
Claim 15 clm-adef2430c060676b descriptive
a Direction it may not vary, revoke or suspend without the written consent of the Secretary of State
Published field
lesson · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
Article 5 of the Direction provides that 'The authority must not vary, revoke or suspend its implementation of the local plan for NO2 compliance pursuant to Article 4, without the prior written consent of the Secretary of State.'
Caveat
No claim-specific caveat recorded

Sources carrying this claim

  1. Environment Act 1995 (Bristol City Council) Air Quality Direction 2021 (Defra)
Claim 16 clm-d0c4ee07a831322b descriptive
to work out why two streets stayed above the limit, the council apportioned NOx by vehicle type from a week of anonymised number plate data
Published field
lesson · verbatim
Mapping
mapped · no interpretation or interpolation added by this passport
What the mapping says
Appendix C of the status report states that in 2024 'work continued to better understand why compliance has not been achieved in some limited locations. As part of this work, a source apportionment exercise was carried out for Bond Street and Colston Avenue. This used anonymised automatic number plate recognition data from a seven-day period of Q4 of 2023 to determine the percentage of NOx emissions from different vehicle types'.
Caveat
The report says outputs were used to identify options for further investigation and that the work is ongoing; it does not report a measure adopted as a result.

Sources carrying this claim

  1. Bristol City Council — 2025 Air Quality Annual Status Report (authority)

Source dossiers and revision state

This layer records what is known about each source, what is still missing, and the exact snapshot this page is rendering. A missing date, archive or hash stays visible as missing.

unreviewed Revision 2026-08-25-bristol-baseline effective 2026-08-25 · created 2026-08-25

Awaiting operator and domain-expert review; publication of this revision implies neither.

sha256:e3ae9d8628f2d075a0723ee9067fa721686a5a2b37dce897cb3fd83ca1c7ba24
Revision history → Permanent version link → Machine-readable record → Evidence Constitution →
16
of 16 claims mapped
7
source dossiers
4
publication dates recorded
0
archives linked
0
exact locators
0
content captures hashed

Governance facts carried by the record

Operator
Bristol City Council
Actor types
city-government, national-government
Funding model
public
Funding description
UK government (Joint Air Quality Unit) grant funding, then charge revenue
Cost
Not recorded
Ownership
Not recorded
Decision rights
Not recorded
Exit conditions
Not recorded

7 source dossiers

GOV.UK — Driving in a clean air zone (authority) gov.uk · 4 linked claims

Open original source ↗

Stable source ID
src-b6d1b4390e951ee6
Publisher
Name not classified · gov.uk
Type / language
web-page · language not classified
Published
2020-01-28
Updated
2026-02-12
Source last checked
No source-level check date
Record last verified
2026-08-25
Dossier created
2026-08-25
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

The national list of England's Clean Air Zones. Gives Bristol as Class D covering 1.18 square miles, defines Class D as the only class whose charges reach cars, and its change history dates the start of charging to 28 November 2022. It states that London's low and ultra low emission zones are a separate regime run by the Mayor.

Descriptive only — not page/paragraph exact
Claims linked
Bristol City Council — Pay the Clean Air Zone daily charge (authority) bristol.gov.uk · 3 linked claims

Open original source ↗

Stable source ID
src-1a5516d880c4593e
Publisher
Name not classified · bristol.gov.uk
Type / language
web-page · language not classified
Published
Not recorded
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-25
Dossier created
2026-08-25
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

The operator's charge schedule: £9 for private petrol cars, private diesel cars, taxis and light goods vehicles under 3.5t; £100 for heavy goods vehicles over 3.5t, buses and coaches. It also carries the operating hours and the six-day payment window. A single flat rate per vehicle category, with no variation by measured air quality.

Descriptive only — not page/paragraph exact
Claims linked
Bristol City Council — What are Clean Air Zone Exemptions (authority) bristol.gov.uk · 1 linked claim

Open original source ↗

Stable source ID
src-688a5c6fb10e6dfa
Publisher
Name not classified · bristol.gov.uk
Type / language
web-page · language not classified
Published
Not recorded
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-25
Dossier created
2026-08-25
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

The operator's exemptions page, and the council page that states plainly how the zone is enforced: cameras with automatic number plate recognition, which also recognise exempt vehicles automatically.

Descriptive only — not page/paragraph exact
Claims linked
Environment Act 1995 (Bristol City Council) Air Quality Direction 2021 (Defra) assets.publishing.service.gov.uk · 3 linked claims

Open original source ↗

Stable source ID
src-bfc46f6d725e81e9
Publisher
Name not classified · assets.publishing.service.gov.uk
Type / language
pdf · language not classified
Published
2021-11-01
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-25
Dossier created
2026-08-25
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

The statutory instruction behind the zone, made by the Parliamentary Under Secretary of State at Defra under section 85(5) of the Environment Act 1995. Schedule 1 names the measure as a "Charging Clean Air Zone Class D"; article 4(2) requires compliance "in the shortest possible time, and by 2023 at the latest"; article 5 forbids the council from varying, revoking or suspending it without the Secretary of State's prior written consent. It revokes an earlier 2020 direction to the same council.

Descriptive only — not page/paragraph exact
Claims linked
Bristol City Council — 2025 Air Quality Annual Status Report (authority) bristol.gov.uk · 8 linked claims

Open original source ↗

Stable source ID
src-efb0b9ae9b251edd
Publisher
Name not classified · bristol.gov.uk
Type / language
web-page · language not classified
Published
Not recorded
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-25
Dossier created
2026-08-25
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

The council's statutory Local Air Quality Management report, covering 2024 monitoring data. Source of the 13.2% and 4.7% average NO2 falls, the count of five sites still above the objective in 2024, the progress-table entry "Compliance not yet achieved", the statement that the CAZ charges on Euro class, and the Appendix C description of the ANPR-based source apportionment at Bond Street and Colston Avenue.

Descriptive only — not page/paragraph exact
Claims linked
National Audit Office — Tackling local breaches of air quality (independent audit) nao.org.uk · background

Open original source ↗

Stable source ID
src-0801319cffcea9e9
Publisher
Name not classified · nao.org.uk
Type / language
web-page · language not classified
Published
2022-06-17
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-25
Dossier created
2026-08-25
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Audit of the national NO2 Programme that Bristol sits inside (HC 66, Session 2022-23), published five months before the zone opened. It records that government expected in 2017 that measures would take three years or less with all measures outside London implemented by 2021, and that as at 1 April 2022 the 17 authorities still implementing had been in the programme for 4.5 years on average. It lists Bristol Urban Area among the zones breaching the NO2 annual limit in 2020.

Descriptive only — not page/paragraph exact
Claims linked
Background source; no baseline claim points here
ITV News West Country — Clean Air Zone first-year revenue (press) itv.com · 1 linked claim

Open original source ↗

Stable source ID
src-31b44f5d4866c63b
Publisher
Name not classified · itv.com
Type / language
web-page · language not classified
Published
2024-01-17
Updated
Not recorded
Source last checked
No source-level check date
Record last verified
2026-08-25
Dossier created
2026-08-25
Retrieved copy
No local capture recorded
Archive
No archived copy linked
Content hash
No captured content hash
Locator
Open the recorded source note

Regional broadcast report on the council's first-year figures: more than £31 million taken, £4.8 million of it spent on operating costs, leaving £26.4 million. No independent audit of these figures was found.

Descriptive only — not page/paragraph exact
Claims linked
Known limits of this passport
  • Publisher names and source languages have not yet been classified; domains are recorded without guessing.
  • Existing source notes are descriptive locators, not page- or paragraph-exact citations.
  • A missing archive, publication date or content hash is shown as null rather than inferred.
  • The project-level evidence grade ranks the strongest source in the entry; it is not a truth score for every claim.