Worst air pollution Sliven, today and tomorrow

Today (16 July): Air quality in Sliven is fair. O3 and HCHO are fair; AQI and NO2 are medium; PM2.5, PM10, SO2, CO, and PM1 are good. Pollution peaks around 3:00 AM (NO2: 42.4/100).
Tomorrow (17 July 2026): Air quality in Sliven is fair. HCHO decreases to good; all other pollutants stay as today. Pollution peaks around 1:00 AM (NO2: 40.2/100). Airmine updates local air quality forecasts four times daily.

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Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team

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Sliven's air quality faces significant winter challenges in the southern Balkan foothills, with the surrounding Balkan Mountains creating topographic enclosure that concentrates residential coal burning and vehicle traffic on the E773 under frequent temperature inversions. The Tundja river valley provides limited ventilation, while summer conditions are considerably better with highland breezes providing reasonable natural ventilation.

Today - 16 July | Pollution peaks at 03:00

AQI:

Medium

42.4/100

PM2.5 (fine particles):

Good

11.5/100

PM10 (coarse particles):

Good

3.1/100

NO2 (nitrogen dioxide):

Medium

42.4/100

O3 (ozone):

Fair

31.8/100

SO2 (sulfur dioxide):

Good

5.8/100

CO (carbon monoxide):

Good

0.0/100

HCHO (formaldehyde):

Fair

20.2/100

PM1 (ultrafine particles):

Good

15.5/100

Levels show the poorest local air quality during the day

Tomorrow - 17 July | Pollution peaks at 01:00

AQI:

Medium

40.2/100

PM2.5 (fine particles):

Good

11.5/100

PM10 (coarse particles):

Good

3.5/100

NO2 (nitrogen dioxide):

Medium

40.2/100

O3 (ozone):

Fair

35.3/100

SO2 (sulfur dioxide):

Good

5.0/100

CO (carbon monoxide):

Good

0.0/100

HCHO (formaldehyde):

Good

17.4/100

PM1 (ultrafine particles):

Good

14.6/100

Pollen forecast in Sliven

View pollen forecast

Frequently Asked Questions

Is air quality bad in Sliven right now?

On 16 July 2026, overall air quality in Sliven is fair. O3 is the main pollutant at 31.8/100. Pollution peaks around 3:00 AM (NO2: 42.4/100).

Will air quality be worse tomorrow in Sliven?

On 17 July 2026, air quality conditions in Sliven will be similar to today, with O3 forecast at fair at 35.3/100. Pollution peaks around 1:00 AM (NO2: 40.2/100).

When is air pollution at its worst in Sliven?

Sliven residents notice reduced air quality mainly when linden and acacia pollen peaks, and during spells of the neighbouring Balkan Mountains; conditions usually ease once the wet season or windier weather returns.

Are air quality levels in Sliven based on measurements or forecasts?

It is forecasts derived by downscaling forecasts provided by EU’s Copernicus Atmosphere Monitoring Service (CAMS) by taking into account local conditions such as traffic patterns. CAMS bases its forecast on satellite measurements of particles and chemical compounds in the atmosphere. Airmine’s services were developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team.

Want to see air quality forecasts for other cities in Bulgaria?

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Data provided by Airmine — Last update: 16 July 2026 at 10:33 CEST (Data is updated four times daily.)

This forecast is produced independently using Airmine's own atmospheric data and models.

Unless explicitly made clear, the content on this site has not been paid for by external organisations and is Airmine's sole responsibility.

For long term forecasts and maps, see the Airmine app