Frequently Asked Questions

PlainAirQuality is an independent data portal. Country PM2.5 uses the European Environment Agency Average Exposure Indicator for 28 European countries; Burden of Disease mortality covers 27 of those countries for 2022. Station pages (39 listed) apply a classification-adjusted model from that country AEI. The site tracks 7 regulated pollutants with EU limits beside WHO 2021 guidelines. We do not currently ingest EEA Dataflow E1a hourly series or Copernicus CAMS grids.

This site currently covers 28 countries: the 27 EU member states plus the United Kingdom. The UK is included as a co-publisher of equivalent regulatory data under the 2010 Air Quality Standards Regulations (post-Brexit DEFRA/AURN network remains methodologically aligned with EEA reporting).

This site currently tracks 7 pollutants regulated by the EU Ambient Air Quality Directive 2008/50/EC: PM2.5 (fine particulate matter), PM10 (coarse particulate matter), NO2 (nitrogen dioxide), O3 (ground-level ozone), SO2 (sulfur dioxide), CO (carbon monoxide), and C6H6 (benzene). Each pollutant has its own detail page covering the EU limit value, WHO 2021 guideline, primary emission sources, health-impact summary, and EN-standard reference measurement method.

No. Individual station pages show classification-adjusted modeled estimates derived from the country's EEA-reported population-weighted average (traffic/background/industrial multipliers). They are labeled as estimates on-page. See the methodology for the exact rule. Country and pollutant pages restate published EEA series.

The EU limit is the legally enforceable concentration set by Directive 2008/50/EC. The WHO guideline is the health-evidence target set by the World Health Organization in their 2021 Global Air Quality Guidelines update. The WHO guidelines are substantially stricter, for PM2.5, the WHO annual guideline is 5 micrograms per cubic metre vs the current EU limit of 25 (Directive 2008/50/EC), which falls to 10 by 2030 under the 2024 revision. For NO2, WHO 2021 is 10 vs the EU limit of 40. A revised EU directive adopted in October 2024 (Directive (EU) 2024/2881) will tighten EU limits closer to WHO guidance by 2030. We show both benchmarks on every detail page so you can see legal compliance and health risk separately.

Two wired EEA series, transcribed in August 2026. (1) Average Exposure Indicator for PM2.5, Table 3 of the Air Quality Status Report 2025 (three-year urban-background mean for 2021-2023). The United Kingdom is not in that table; its PM2.5 figure is an editorial composite. (2) Burden of Disease PM2.5 mortality for 2022, 27 countries with a published row (no UK row). Mentions of Dataflow E1a, Copernicus CAMS, or national-agency live feeds elsewhere are context for benchmarks and future ingest - those feeds do not populate today's numbers. WHO 2021 guidelines and EU Directive limits are cited as benchmarks only.

The wired AEI and Burden of Disease rows are transcribed from named EEA releases; the August 2026 extract is the current vintage. We do not auto-ingest Dataflow E1a or refresh within two weeks of every EEA release - that claim previously overstated our pipeline. When a new AEI or Burden of Disease table ships, we re-transcribe and note it in the changelog.

PM2.5 (particles smaller than 2.5 micrometres in aerodynamic diameter) penetrates deep into the lungs, crosses into the bloodstream, and reaches every organ in the body including the brain. The International Agency for Research on Cancer classifies outdoor PM2.5 as a Group 1 human carcinogen. The European Environment Agency attributes approximately 238,000 premature deaths per year across the EU-27 (EEA, 2022 burden-of-disease assessment; modeled estimates, and the EEA does not publish a UK figure) to PM2.5 exposure, primarily from cardiovascular disease, stroke, ischemic heart disease, lung cancer, and chronic obstructive pulmonary disease. The WHO 2021 guideline of 5 micrograms per cubic metre reflects the lowest concentration at which adverse effects have been observed across well-conducted cohort studies.

Yes, in most cases. The EU limit (PM2.5 annual: 25 micrograms per cubic metre, falling to 10 by 2030 under the 2024 revision; NO2 annual: 40 micrograms per cubic metre) is a regulatory threshold; exceeding it triggers air-quality action plan obligations on the member state. The WHO 2021 guideline is a health-evidence target, it is not legally binding. Many European cities sit in the gap between the two: legal under EU law but above the concentration at which health risk is meaningfully elevated according to WHO. The 2024 EU directive revision will close some of this gap by 2030.

EEA station classifications follow EU implementing Decision 2011/850/EU. A traffic station is sited within 10 metres of a road kerb to capture peak roadside exposure. A background station is sited away from any major direct emission source to capture ambient (urban or rural) air. An industrial station is sited within 250 metres of an industrial emission source. Traffic stations typically read 20–40% higher than co-located background stations for NO2 and PM2.5; ozone is the inverse (ozone titrates against NOx, so ozone is often lower at traffic sites).

Recommended citation: PlainAirQuality, "[Page Title]", https://plainairquality.com/[path]/, accessed [date]. For underlying data, cite the original source: European Environment Agency, Air Quality Status Report 2025 Average Exposure Indicator Table 3, and EEA Burden of Disease (2022). For WHO benchmarks: World Health Organization, WHO global air quality guidelines (2021), https://www.who.int/publications/i/item/9789240034228.

PlainAirQuality ships a statistics CSV of the wired AEI and Burden of Disease extract on hub pages. For broader regulatory observations or reanalysis, download directly from the EEA Datahub or the Copernicus Atmosphere Data Store - those feeds are not what populate this site today. We link methodology so you can verify any number we publish.

No. PlainAirQuality is an independent data-journalism publisher. We are not affiliated with the EEA, the European Commission, Copernicus, the WHO, or any member-state government. We do not accept payment from government agencies, industry trade groups, or environmental NGOs for the editorial content on this site.