Methodology
How we detect and classify calima events
Data Sources
We aggregate data from multiple trusted meteorological sources to provide accurate air quality information.
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Open-Meteo Air Quality API
Provides PM10 and Saharan dust concentration data from the Copernicus Atmosphere Monitoring Service (CAMS).
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AEMET (Spanish Meteorological Agency)
Official dust warnings and meteorological forecasts for Spain and the Canary Islands.
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University of Athens (SKIRON)
Dust load forecast maps with 3-hour resolution for the North Atlantic and Mediterranean regions.
PM10 Thresholds
Air quality levels are classified based on PM10 particle concentration (particles ≤10µm in diameter).
| Level | PM10 Range | Health Impact |
|---|---|---|
| Good | 0–20 µg/m³ | Minimal health impact expected. Generally safe for outdoor activities. |
| Moderate | 21–50 µg/m³ | Sensitive groups may notice mild symptoms. Corresponds to Spain's legal 24h limit (50 µg/m³). Individual sensitivity varies. |
| Unfavorable | 51–150 µg/m³ | Some people may experience symptoms. Official guidance typically advises limiting outdoor activities. |
| Very Unfavorable | >150 µg/m³ | Official guidance for this level typically advises staying indoors with windows closed and limiting outdoor exposure. Consult official health authorities. |
Reference: WHO Air Quality Guidelines (2021), Spanish RD 102/2011. These are general thresholds. Individual sensitivity varies.
Calima Detection
Our algorithm distinguishes Saharan dust (calima) from urban pollution using multiple signals:
- 1.PM10 concentration exceeds 50 µg/m³ (Spain's legal limit)
- 2.Saharan dust concentration > 30 µg/m³ (indicates significant desert dust)
- 3.Dust-to-PM10 ratio ≥ 60% (confirms Saharan origin vs. urban pollution)
When all criteria are met, the episode is classified as "calima". High dust alone (>100 µg/m³) triggers detection regardless of ratio.
Update Frequency
Data is refreshed automatically to provide near real-time information.
- Air quality data: Every 15 minutes
- Forecast data: Every 15 minutes
- SKIRON dust maps: Every 6 hours
Limitations
- Forecasts are model-based and may differ from actual conditions.
- Air quality can vary significantly within short distances.
- For large islands (Tenerife, Gran Canaria), zone data represents approximate areas based on reference coordinates (airport areas). Actual conditions may differ within each zone.
- For official warnings, always consult AEMET and local authorities.