The Air Quality — European Air Quality Index (EAQI) is a composite indicator that integrates the concentrations of five key atmospheric pollutants — PM10, PM2.5, O₃ (ozone), NO₂ (nitrogen dioxide), and SO₂ (sulphur dioxide) — into a single daily air quality index. Defined by the European Environment Agency (EEA), the EAQI follows the "worst-of-five" approach: the overall index level is determined by whichever pollutant has the worst concentration relative to its regulatory limits.
The EAQI scale ranges from 1 (Good) to 5 (Extremely Poor):
| Level | Index Value | EEA Classification | Health and Ecological Significance |
|---|---|---|---|
| Good | 0 — 40 | Good | No significant impact on health and ecosystems |
| Fair | 40 — 60 | Fair | Possible mild effects for sensitive groups |
| Moderate | 60 — 80 | Moderate | Moderate effects for sensitive groups |
| Poor | 80 — 100 | Poor | Health effects for general population |
| Very Poor | > 100 | Very Poor | Severe health and ecosystem effects |
The EAQI is the official European standard for air quality communication, compliant with Directive 2008/50/EC on ambient air quality and cleaner air for Europe. It is a sub-indicator of the broader air_quality KPI, providing a standardised cross-site comparison metric. The index value is dimensionless.
The EAQI is sourced from the Open-Meteo Air Quality API, which in turn draws on the Copernicus Atmosphere Monitoring Service (CAMS) model. The specific variable is european_aqi — the pre-computed composite European Air Quality Index.
Processing pipeline:
EEA worst-of-five methodology:
The EAQI for each hour is determined by computing individual sub-indices for PM10, PM2.5, O₃, NO₂, and SO₂ based on their respective concentration thresholds. The overall EAQI is the maximum (worst) of the five sub-indices — reflecting the pollutant of greatest concern at that moment.
Unit: Dimensionless index (scale 0–100+, classified into 5 quality bands).
| Source | Provider | Coverage | Resolution | Period |
|---|---|---|---|---|
| Open-Meteo Air Quality API (CAMS) | Open-Meteo / Copernicus Atmosphere Monitoring Service | Global (Europe: 11 km) | 11 km | 2013 — present |
Line Chart. A time-series chart displaying hourly air quality values for the site, with pollutant selection and time period filtering.
Purpose: Answers the question "What is the air quality trend at this site over time, and how do individual pollutant concentrations vary?"
Description: The chart card has a header row with the title "Air quality" and an ESRS topic badge "E1". A pollutant selector dropdown allows switching between PM10 (default), PM2.5, and other available variables including the EAQI composite. A time granularity toggle offers "Hourly" resolution. An "Add data" button enables data overlay. The chart area displays data points over the selected period, with the X-axis showing time and the Y-axis showing the pollutant concentration or index value. Filter controls at the top allow selecting the time period (year, custom range). Summary statistics (Minimum, Average, Maximum) are shown above the chart for the selected period.
How it's calculated: Each data point represents the hourly or daily value of the selected pollutant variable from the Open-Meteo Air Quality API (CAMS model). When the EAQI composite is selected, values follow the 0–100+ scale where the index is determined by the worst-performing pollutant. For PM10 and PM2.5, values are in micrograms per cubic metre. The chart supports zooming and scrolling to navigate the full time range.
Legend: Data point colours follow the 5-band EAQI scale:
| Level | Range | Color | Meaning |
|---|---|---|---|
| Good | 0 — 40 | ■ #00A67A | Air quality is satisfactory |
| Fair | 40 — 60 | ■ #00DF80 | Acceptable; possible mild effects for sensitive individuals |
| Moderate | 60 — 80 | ■ #FFD21E | Moderate concern for sensitive groups |
| Poor | 80 — 100 | ■ #FF8B16 | Health effects for general population |
| Very Poor | > 100 | ■ #FF367F | Serious health effects; emergency conditions |
Interpretation example: If the chart shows PM10 values averaging 35 during winter months but spiking to 85 on specific days, the site generally enjoys Fair air quality but experiences episodic Poor conditions likely driven by atmospheric stagnation or nearby emission sources — triggering ecological stress for sensitive species and habitats.
Line Chart. A dedicated time-series chart showing particulate matter (PM10 and PM2.5) threshold exceedances over the monitored period.
Purpose: Answers the question "How often do particulate matter concentrations at this site exceed regulatory thresholds?"
Description: The chart card has a header row with the title "Threshold exceedance PM" and an ESRS topic badge "E1". Toggle controls allow switching between PM10 and PM2.5. An additional "Thermal" filter and a "Pollution" category label indicate the thematic context. The chart plots daily particulate values against the EU regulatory thresholds, highlighting exceedance events. This component complements the EAQI line chart by focusing specifically on particulate matter compliance.
How it's calculated: Daily PM10 and PM2.5 concentrations are compared against EU Directive 2008/50/EC daily limit values (PM10: 50 micrograms per cubic metre daily limit, not to be exceeded more than 35 times per year; PM2.5: 25 micrograms per cubic metre annual mean limit). Days exceeding the threshold are visually highlighted.
Interpretation example: If the chart shows 12 PM10 exceedance days in the first quarter, the site is on track to exceed the EU annual allowance of 35 days — suggesting structural air quality issues that affect both human health and ecosystem integrity at the site.
Highlights Card. A risk analysis card within the Pollution risk category tab, displaying the air quality risk level based on premature mortality attributable to air pollution.
Purpose: Answers the question "What is the health and environmental risk from air pollution at this site, assessed through mortality impact data?"
Description: The "Air quality" tab appears in the "Key risk aspects" section under Pollution risks. When active, it displays the shared risk layout: a site name and coordinates header, a risk grade badge (A through E), a "Mortality rate due to air quality" value (deaths per 100,000 inhabitants), a Physical risk grade, Sensitivity score, Impact level, Impact risk grade, Damage factor, and Economic value at risk fields. Below, a methodology description explains the single-indicator approach using premature mortality attributable to air quality.
How it's calculated: The risk level is derived from a single direct indicator: the premature mortality rate attributable to air quality (annual premature deaths per 100,000 inhabitants caused by exposure to air pollutants, primarily PM2.5). Risk levels are mapped against absolute mortality thresholds, benchmarked to global annual mortality rates from other causes. This assessment follows the risk framework described in E. Pisoni et al. (2025) and H. Yue et al. (2024).
Legend:
| Level | Mortality Rate | Color | Meaning |
|---|---|---|---|
| A | Very Low | ■ #00A67A | Minimal health impact from air pollution |
| B | Low | ■ #00DF80 | Below-average mortality burden |
| C | Moderate | ■ #FFD21E | Moderate health impact; attention warranted |
| D | High | ■ #FF8B16 | Significant premature mortality from air pollution |
| E | Very High | ■ #FF367F | Severe health crisis from air pollution |
Interpretation example: If the card shows a mortality rate of 134.35 per 100,000 with a grade D, the site is located in an area where air pollution contributes significantly to premature deaths — indicating that both human populations and ecological receptors (vegetation, pollinators, aquatic life) face chronic exposure to harmful pollutant levels.
Highlights Card. A portfolio-level counter card in the Overview Risk Overview slider showing how many monitored sites have above-average air quality risk.
Purpose: Gives portfolio managers an immediate view of how many sites are affected by air quality issues across their entire portfolio.
Description: The card displays a label indicating the number of sites with above-average air quality risk and a count in the format "X / Y sites". The card is part of the horizontal slider of risk counter cards on the overview page, alongside counters for climate change, flood risk, and other risk categories.
How it's calculated: Each site is evaluated against the air quality risk threshold. Sites exceeding the threshold are flagged. The counter sums all flagged sites across the portfolio.
Interpretation example: If the card shows "8 / 15 sites", it means over half of the monitored sites are located in areas where air pollution poses a significant environmental and health risk — warranting portfolio-wide mitigation strategies.
European Environment Agency (2022). "Air quality in Europe 2022." EEA Report No 05/2022. https://www.eea.europa.eu/publications/air-quality-in-europe-2022
European Commission (2008). Directive 2008/50/EC of the European Parliament and of the Council on ambient air quality and cleaner air for Europe. Official Journal of the European Union, L 152, 1–44. https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:32008L0050
EEA (2023). "European Air Quality Index — Methodology." https://airindex.eea.europa.eu/AQI/methodology.html
Open-Meteo (2024). "Air Quality API Documentation." https://open-meteo.com/en/docs/air-quality-api
Pisoni, E., et al. (2025). Air pollution mortality indicators for environmental risk assessment. (Reference used in platform risk methodology)
Yue, H., et al. (2024). Health impact assessment of ambient air quality in urban environments. (Reference used in platform risk methodology)
See the Calculation Methodology section for the core computation. Additional processing details are documented here for expert users.
air_quality parent KPI. It provides the composite European index value while sibling KPIs cover individual pollutants (PM10, PM2.5, O₃, NO₂, SO₂) separately.