Tuesday, 21. 2. 2017

Air quality in Ljubljana

Measurements of PM10 particle air pollution for the past ten years show that air quality in Ljubljana is gradually, yet persistently improving.

The quality of air in Ljubljana is monitored by permanent automated measuring devices at four measuring points and occasional measurements at different locations across the city and on its outskirts. Three monitoring points are part of the national monitoring network (Ljubljana Bežigrad – Slovenian Environment Agency, Ljubljana Exhibition and Convention Centre, Ljubljana Biotechnical Faculty). The fourth monitoring point Ljubljana Center is at the crossroads of Vošnjakova and Tivolska and is managed by the City of Ljubljana. It is a traffic station set up at a location with heavier traffic, thus individual parameter values are higher than elsewhere. The monitoring point Ljubljana Bežigrad is most representative of Ljubljana.
In 2016, we marked ten years of measuring PM10 particle air pollution at the Ljubljana Center monitoring point. The measurements are conducted with an automated measuring device TEOM. The extensive time coverage with data ensures data reliability.
The credibility of data is also checked with parallel PM10 particle measurements with the gravimetric measuring device LEKL.

Measurement summary
Air quality in Ljubljana is gradually improving.
The data undeniably shows that air pollution in Ljubljana is, despite the high annual fluctuation which is a consequence of given weather conditions, gradually, yet persistently decreasing. The data also indicates that particle pollution, at the level of the average annual value and also with regard to the number of interventions in the warm part of the year (outside the heating season), has considerably fallen. In addition, it is significant that at the traffic station Ljubljana Center the average annual particle value has not exceeded the permitted value of 40 µg/m3 for the third consecutive year. The number of daily exceeded values has significantly lowered but it is nevertheless above the allowed 35 days in a calendar year.

Exceeded PM10 particle values in the winter heating season
During the winter heating season the quality of air is unfortunately not improving.
Adverse weather conditions in the heating season lead to higher air pollution levels. Due to its basin location, poor ventilation and high population density Ljubljana is especially prone to such situations. There are no efficient short term measures that could instantly reduce air pollution. Even with car traffic reduction the current pollution would not decrease because during the winter season the biggest problem remains the use of individual furnaces in apartments and handicraft workshops and the control over them. As furnaces in the whole Ljubljana basin contribute to air pollution, especially in more densely populated areas, where they use wood biomass for heating, conditions cannot be managed at local level just by introducing stricter measures in the City of Ljubljana.

In the past Ljubljana has implemented numerous systemic measures to improve air quality and that is why the quality of air has been rising over the years. In particular the construction of both distance heating systems satisfying almost 75% of heating energy needs in the city centre has to be mentioned here and they are also being successfully expanded to the city outskirts and neighbouring settlements. Just to add, the Decree on the priority use of energy products for heating in the area of the City of Ljubljana was adopted in 2016.
Currently the City of Ljubljana, in cooperation with the Ministry of the Environment and Spatial Planning, is preparing an amended Decree on the air quality plan in the area of the City of Ljubljana for the period from 2017 until 2020 with an emphasis especially on individual furnaces, stricter monitoring and educating owners of combustion installations.