kanarche
Air quality in Sofia
For 14 of the 27 provincial capitals this boundary is the whole municipality, not just the city. About the data
Sofia right now: PM2.5 2.6 µg/m³, air quality is good. Median of 249 sensors, data as of .
This figure is indicative. Some citizen stations may be old or faulty, and we do not calibrate them. For health advice, follow official sources.
Over the last 24 hours the median ranged between 1.5 µg/m³ (yesterday at 13:45) and 13.2 µg/m³ (yesterday at 09:25).
Each cell is the median of the ground beneath it
The list of provinces below the map carries the same readings as text.
Pollen forecast
| Pollen | |||
|---|---|---|---|
| Ragweed | Low0.0 | Low0.0 | Low0.0 |
| Mugwort | Low0.0 | Low0.0 | Low0.0 |
| Grasses | Low0.1 | Low0.1 | Low0.1 |
| Birch | Low0.0 | Low0.0 | Low0.0 |
| Alder | Low0.0 | Low0.0 | Low0.0 |
| Olive | Low0.0 | Low0.0 | Low0.0 |
Daily mean, grains per cubic metre of air. A model forecast for orientation, not a measurement and not medical advice.
Questions about the air in Sofia
What is the air quality in Sofia right now?
The figure at the top of this page is the current value for Sofia. It is the median of the sensors that reported recently, with its band on the European Air Quality Index. The value is indicative and we do not give health advice. For official alerts, follow the Ministry of Health, the regional health inspectorates (РЗИ) and the Executive Environment Agency (ИАОС).
What are PM2.5 and PM10?
PM2.5 and PM10 are fine particles in the air, up to 2.5 and up to 10 microns across. They are measured in micrograms per cubic metre (µg/m³). In Bulgarian they are called ФПЧ2.5 and ФПЧ10. The map shows both, and you can switch between them in the metric menu.
What do the colours on the map mean?
The colours follow the bands of the European Air Quality Index. They run from blue green for good, through yellow and red, to purple for extremely poor. For PM2.5, good is up to 5 µg/m³, fair up to 15, moderate up to 50, poor up to 90, very poor up to 140, and above that extremely poor. For PM10 the same bands end at 15, 45, 120, 195 and 270. Grey means there is not enough data.
How often is the data for Sofia updated?
The map fetches new readings from citizen sensors every 5 minutes. A sensor that has sent nothing for 2 hours no longer counts toward the current value. Official stations publish hourly averages with a delay of several hours, so their readings count for 12 hours. The time of the latest data is shown next to the value.
Where does the air quality data for Sofia come from?
Most readings come from low-cost sensors run by volunteers in the Sensor.Community network. Their data is open under the ODbL 1.0 licence. Kanarche is an independent, non-commercial project. It is not affiliated with Sensor.Community or with airbg.info. Official stations of the Executive Environment Agency (ИАОС) in Sofia are shown too. Their data comes through the European Environment Agency.
Why do these numbers differ from the official stations?
Citizen sensors are low-cost optical sensors. They are not reference instruments and we do not calibrate them. High humidity in particular makes them read higher. They also stand in different places from the official stations, and the value for Sofia is a median of several sensors. Official stations report hourly averages several hours later. Citizen data is good for seeing change over time and differences between places. More in "About the data".
Why is there sometimes no value for Sofia?
We publish a value only when at least three separate locations report usable readings. A sensor is inactive when it has sent nothing for 2 hours. A sensor is faulty for a measurement when at least half of its readings in the last 24 hours failed the quality checks, counting at least 6 readings. Faulty readings are left out of the value. You can show inactive and faulty stations in Layers.