Cleanest air for outdoor sport

Each pollutant adds to the score independently based on its concentration relative to its WHO 2021 24-hour guideline and its long-term health impact. PM2.5 contributes the most (9 points at its WHO limit), followed by NO₂ (5), O₃ (3), PM10 (2), and SO₂ (1). PM2.5 and PM10 use a non-linear curve that is steeper at low concentrations, reflecting the GBD GEMM dose-response evidence. NO₂, O₃ and SO₂ scale linearly. All pollutants at their WHO limits totals 20, the Excellent boundary.

The European AQI uses the single worst pollutant as the overall score. One elevated reading overrides everything else, which penalises mountain and coastal locations where ozone is naturally higher. It also uses older EU regulatory thresholds rather than the stricter WHO 2021 guidelines. Our additive model means every pollutant matters and more pollution always increases the score, with each pollutant contributing in proportion to its actual long-term health impact.

Open-Meteo, which aggregates data from national air quality monitoring networks and atmospheric models. Readings are live and refreshed every 6 hours.

Higher altitude means less traffic, no heavy industry and better atmospheric dispersion. Coastal spots benefit from onshore breezes that push pollutants inland. Both tend to score well compared to major cities.

PM2.5 is particulate matter under 2.5 micrometres (fine particles from combustion, fires and exhaust). PM10 is under 10 micrometres (dust, pollen, construction). Both are measured in micrograms per cubic metre. The WHO guideline for PM2.5 is 15 µg/m³.

During intense exercise you breathe 10 to 20 times more air than at rest. High PM2.5 can reduce lung function and trigger inflammation. For most people, a score under 40 poses negligible risk even during hard sessions.