ASSESSMENT UNAVAILABLE
No England-wide current environmental assessment is published because the governed monitoring coverage and freshness gate was not met.
The station-level PM2.5 operational screen is reported separately and cannot override the governed England-wide coverage/freshness gate.
Evidence acquisition: PASSED. 11 configured joins remain pending or blocked. The PM2.5 operational screen and England-wide current assessment are distinct from the 30-day England AURN review. Screening evidence only; no source attribution, legal or health finding.
Plain English evidence status
What the latest evidence does — and does not — allow us to say
Insufficient evidence for a national current assessment
We are deliberately not publishing an England-wide current assessment.
No England-wide current environmental assessment is published because the governed monitoring coverage and freshness gate was not met.
Cross-source status: No episode was available for corroboration. Cross-source convergence was not applicable to an episode in this run.
Technical Evidence Centre
Review the machinery behind the public summary
The public view uses plain language. The technical evidence remains available for scientists, journalists, regulators, reviewers and anyone who wants to challenge the result.
Primary evidence product · England 30-day official monitoring review
National coverage criteria met
What England's monitoring data showed
SCC Air Quality analysed 9,544 valid pollutant-day observations across 4,192 unique station-days from 142 reporting stations, covering 9 of 9 English regions between 2026-08-18 and 2026-09-16.
Descriptive pollutant findings
These are measured 30-day station and regional patterns. They are not source-attribution, exposure, health or legal-compliance findings.
Carlisle Morton A595 · North West · 30 valid days
Highest eligible regional median: North West (4.34 µg/m³).
WHO-context pollutant-day observations: 21
Leeds Headingley Kerbside · Yorkshire and the Humber · 27 valid days
Highest eligible regional median: North West (9.20 µg/m³).
WHO-context pollutant-day observations: 1
Stoke-on-Trent A50 Roadside · West Midlands · 30 valid days
Highest eligible regional median: London (13.70 µg/m³).
WHO-context pollutant-day observations: 115
Interpretation boundary: provisional official monitoring evidence; WHO guideline comparisons are contextual and are not UK legal exceedance counts.
Evidence pathways for science, public health, policy, journalism and communities
SCC Air Quality separates the successful England 30-day review from the current live episode screen and provides routes to data, methods, provenance, corrections and external review.
Use the evidence External review pack Contact and corrections
9/9 regions · 142/143 stations · 9,544 pollutant-day observations across 4,192 unique station-days · 96.3% completeness.
Current data service
Live monitoring active across 129 fresh sites
228 of 237 time series were inside the freshness window and 0 preliminary screening observation(s) were selected for follow-up.
Measurement coverage
Fresh physical monitoring sites129 / 133
Selected monitoring locations inside the evidenced geography and freshness window · 97%
Fresh PM time series228 / 237
PM2.5 and PM10 streams with recent usable observations · 96%
Operational PM2.5 screening snapshot
The screen compares eligible PM2.5 assessments with a short recent-history window. Formal false-discovery-rate control has not been established. A candidate is a review prompt, not a legal exceedance, source finding or health determination.
Official monitoring network
172 active AURN sites discovered across England
The public review distinguishes active sites, configured pollutant streams, reporting stations and station-day completeness. Monitoring evidence is shown separately from the supplementary context layer.
Explore station and regional results Open monitoring and context map
How this review now works
Official monitoring data leads. No location-specific follow-up was activated.
The England-wide monitoring screen runs first. Because no fresh screening event fixed a time window and geographic footprint, no location-specific context was queried or promoted into the active review.
Target-neutrality preserved · no post-discovery context query activated. Proximity and register matches remain context only and cannot establish contribution.
Current measurements
Inspect official PM2.5 and PM10 coverage, data-quality exclusions, screening observations and cross-source execution in one public dashboard.
Explore current statusDaily Air-Quality Evidence Status
Read a public summary organised around what changed, what was checked, what remains uncertain and what evidence is required next.
Read the weekly briefingMethod and provenance
Review acquisition, quality control, statistical screening, evidence linkage and hard claim boundaries in reproducible detail.
Review methodsForensic scientific evidence review
Inspect evidence coverage, freshness, source maturity, executed cross-references, uncertainty and explicit non-conclusions.
AI and model assurance
Review current deterministic execution, prohibited automated uses, evaluation gates and model provenance.
Scientific evidence and software assurance are different
Scientific evidence
Measurements, station and regional coverage, descriptive calculations, source records and stated limitations are the evidence available for review.
Engineering assurance
Automated checks confirm that the pipeline followed its declared rules. They do not constitute peer review, accreditation, regulatory approval or institutional endorsement.
Operational PM2.5 screening interpretation
Adjusted PM2.5 candidate count: 0; eligible station assessments: 120; not eligible or not assessed: 7. A count of zero means only that no eligible assessment crossed every current operational criterion. It does not establish absence of pollution, harmless concentrations, assessment of every station or screening of all pollutants.
Formal false-discovery-rate control has not been established. The live screen does not identify a source and is not a health assessment or regulatory determination.
Why the monitoring denominators differ
The observatory publishes separate products with separate eligibility gates. Their counts must not be treated as one denominator.
133current-screen identified sites
—30-day review stations with governed evidence
—AURN sites discovered by the review inventory
- Discovered sites are the discovery inventory before eligibility filters.
- 30-day review stations have governed evidence for the completed window.
- Current-screen sites belong to the separate operational PM2.5 screen.
Series terminology
Identified series are configured/discovered pollutant time series. Reporting series supplied accepted numeric observations. Fresh series/sites meet the governed freshness window.
235 / 237reporting / identified series
129current sites meeting freshness gate
Routine evidence convergence
237ordinary current observations eligible for routine convergence
2 / 2applicable routine joins executed
0routine joins fully validated
Routine convergence runs independently of anomaly detection. A day with zero screening candidates can still produce useful meteorology and monitor-role corroboration.
Sentinel-5P processing state
36recent catalogue items discovered
0 / 1bounded products processed
0QA-valid pixels retained across processed products
Satellite processing status: not configured product download credentials. Sentinel-5P Level-2 products are column/context evidence, not ground-level monitor concentrations. The processing receipt retains product-specific QA, product identifiers, hashes, numerical summaries and compact provenance imagery.
Traffic evidence: what is actually available
10,000 official DfT traffic recordsrecords downloaded
2025AADF evidence year
annual average daily flowtemporal resolution
The build acquired official DfT AADF records for 2025, providing annual traffic and vehicle-class baseline context.
Boundary. Annual AADF evidence is not contemporaneous event traffic. Event-specific traffic still requires time-aligned observations such as WebTRIS or equivalent official data before traffic can support an episode-level competing-source assessment.
Operational PM2.5 screen: threshold and multiplicity boundary
The current screen uses operational screening parameters including a 24-hour PM2.5 mean floor of 15 µg/m³ and a robust station-history score of 3 or greater. These are project screening parameters, not UK legal limits, WHO guideline values, health thresholds, or evidence of a pollution source.
Calibration status. Until an empirical null, sensitivity analysis and dependence-aware calibration are published, the project does not claim that the nominal Benjamini–Hochberg alpha establishes a validated false-discovery rate. The scores are screening statistics rather than calibrated p-values.
WHO context is not UK legal compliance
For NO₂, the WHO 2021 annual air-quality guideline is 10 µg/m³, while the UK statutory annual-mean limit value/objective is 40 µg/m³. WHO-context pollutant-day counts must not be interpreted as UK legal exceedance counts.