Key messages
Concentrations of sulphur dioxide in ambient air do not represent a danger for human health in urban areas any longer. Also a critical annual value for the protection of vegetation is not exceeded any more. Improvement of the situation in last decade is a result of a use of high quality fuels in industry and operation of desulphurisation facilities in the thermal power plants.
The measured concentrations of nitrogen dioxide and total nitrogen oxides in outdoor air do not exceed the prescribed limit values, so pollution with these two pollutants is not dangerous to human health and vegetation.
The level of air pollution by ozone in recent years is above the target value on the majority of locations, including in rural areas and at higher altitudes, while the action value of less sunny and hot summers exceeded only in the Littoral and in some places in the higher altitudes. The most polluted area is Primorska of favorable weather for ozone formation and transport of ozone and its precursors from northern Italy.

 Air pollution with particulate matters is decreasing. In 2012, the annual limit value for PM10 has exceeded only at one measuring point. Wather conditions and individual heating appliances (during the heating season), partly also transport, industry and re-raising and floating particles in the atmosphere.

Total emissions of the pollutants that contribute to acidification and eutrophication have decreased by 75% in Slovenia between 1990 and 2014. Emissions of SOx have decreased by 96 %, NOx by 42 % and NH3 by 20 %. The emissions of sulphur oxides, nitrogen oxides and ammonia were in 2014 lower than the prescribed target values.

Emissions of total ozone precursors decreased by 51 % in the period 1990 to 2014. Emissions of nitrogen oxides decreased by 42%, carbon monoxide by 67 %, non-methane volatile organic compounds by 56% and methane by 20 %. The reason is mainly the introduction of more stringent emission standards for motor vehicles. This measure contributed to a significant reduction in emissions of nitrogen oxides and carbon dioxide from road transport which is the main source of ozone precursors. Emissions of nitrogen oxides and non-methane volatile organic compounds were in 2014 under the prescribed target values, which must not be exceeded from 2010 onwards.
Heavy metal emissions in Slovenia significantly decreased between 1990 and 2014. This can be largely attributed to the implementation of the EU legislation, improved surveillance and use of the best available technologies.
Emissions of persistent organic pollutants in Slovenia in the period 1990-2014 decreased primarily due to a combination of targeted legislation, improved control and use of best available technologies.

The emission of primary particles, smaller than 10 µm (PM10), particles smaller than 2.5 µm (PM2.5) and all dust particles (TSP) have decreased in the period 2000 – 2014 in Slovenia by 15 %, 5 % and 22 %. The main source of emissions of particulate matter are households, mainly because the use of biomass for heating.

The decrease in SO2 emissions impact of tightening legislation concerning the concentration of sulfur in liquid fuels. Allowable concentration of sulfur in fuels in 2012 were not exceeded. 

Concentrations of metals in the ambient air in Slovenia do not exceed the prescribed limits. The annual target value for benzo ( a) pyrene was exceeded at the sampling points in Ljubljana and Maribor, which are under the influence of emissions from transport.
Air pollution by ozone in the recent years is above target value on all locations. Furthermore the value is above long-term value.