National Institute of Geophysics, Geodesy and Geography-
Bulgarian Academy of Science
National Institute of Meteorology and Hydrology

BULGARIA

SOFIA

PLOVDIV

VARNA

Nitrogen Dioxide (NO2) Ozone
(O3)
Sulfur Dioxide
(SO2)
Fine Particulate Matter(PM10) Fine Particulate Matter(PM2.5) Air Quality Index
(AQI)
Dominant pollutant (DPI) Universal Thermal Climate Index (UTCI)
16Jun17Jun18Jun

Within the framework of the National Scientific Program " Environmental Protection and Reduction of Risks of Adverse Events and Natural Disasters" funded by the Ministry of Education and Science, the System for Chemical Weather Forecast (air pollution) was created. The System present the 72 hours forecast for air pollution in real-time, starting from 00:00 of the current day and extending two more days ahead for the territory of Bulgaria, with a spatial resolution of 3 km and for three selected cities - Sofia, Plovdiv, and Varna, with a resolution of 1 km each.

For each of the mentioned domeins, one of the five main pollutants can be selected - Nitrogen Dioxide (NO2), Ozone (O3), Sulfur Dioxide (SO2), Fine Particulate Matter with a diameter below 10 µm (PM10), Fine Particulate Matter with a diameter below 2.5 µm (PM2.5), from which the Air Quality Index (AQI) is calculated and visualized. The system also forecasts the Universal Thermal Comfort Index (UTCI), indicating the thermal comfort/discomfort of the human body.

Air Quality Index (AQI)

The Air Quality Index provides information on the predicted state of air quality, and directly measure its effects on human health based on calculations for forecasting the five pollutants.Each pollutant has reference levels defined (in μg/m3), and according to these values the private air quality index (the index corresponding to the given pollutant) is determined. The overall air quality index is the highest level of pollution caused by each of the five pollutants.
A lots of air quality indexes are calculated in the world, eah contry decide which pollutants are in concern in there territory and add it in the index calculations. In the system, the European AQI was used, that includes 5 pollutants in concern in Europe: Ozone (O3); Nitrogen dioxide (NO2); Sulphur dioxide (SO2); Particulate matter (PM10) and fine particulate matter (PM2.5).
When presenting the air quality index to the pollutant reference levels, a color scale has been added, as well as health recommendations for both the general population and sensitive populations. The latter includes both adults and children with respiratory problems and adults with heart conditions.Both adults and children with respiratory problems and adults with heart diseases are included in the sensitive groups. The health recommendations and reference levels used in the formation of such tables and scales are related to the directives on the limit levels for the protection of human health, determined by the European Union and/or by the World Health Organization.

AQ index General population Sensitive populations
Good The air quality is good. Enjoy your usual outdoor activities. The air quality is good. Enjoy your usual outdoor activities.
Fair Enjoy your usual outdoor activities Enjoy your usual outdoor activities
Moderate Enjoy your usual outdoor activities Consider reducing intense outdoor activities, if you experience symptoms.
Poor Consider reducing intense activities outdoors, if you experience symptoms such as sore eyes, a cough or sore throat Consider reducing physical activities, particularly outdoors, especially if you experience symptoms.
Very poor Consider reducing intense activities outdoors, if you experience symptoms such as sore eyes, a cough or sore throat Reduce physical activities, particularly outdoors, especially if you experience symptoms.
Extremely poor Reduce physical activities outdoors. Avoid physical activities outdoors.

https://airindex.eea.europa.eu/Map/AQI/Viewer/#