Concentrations of sulphur dioxide in ambient air are no longer harmful for human health. Also, the critical annual value for the protection of vegetation is no longer exceeded. The improvement of the situation in the last decade is a result of the use of low-sulphur fuels in industry and the operation of desulphurisation facilities in thermal power plants.

The level of air pollution with ozone has exceeded the target value for protecting human health in recent years at some urban background monitoring stations (Koper, Nova Gorica Grčna) and at the higher-altitude monitoring station Otlica. The long-term health protection goals have been exceeded at all monitoring stations. The warning value has also been exceeded in recent years only in the Primorska region and at higher altitudes, such as Otlica.

Air pollution with PM₁₀ was the lowest in 2021 since we have been carrying out measurements. For the first time, at no monitoring site did the sum of exceeding the daily limit value for PM₁₀ (50 µg/m³) exceed the number of 35, which is allowed for the whole year. Even the annual limit value for PM₁₀ in 2021 was not exceeded at any monitoring site.

In Slovenia, total emissions of the pollutants that contribute to acidification and eutrophication have decreased by 81 % between 1990 and 2021. Emissions of SO_x have decreased by 98 %, NO_x by 66 % and NH₃ by 22 %. The emissions of sulphur oxides, nitrogen oxides and ammonia were in 2021 below the prescribed target values. Slovenia also met its emission reduction commitments compared to the year 2005.

Emissions of total ozone precursors in Slovenia decreased by 62 % in the period 1990 to 2021. Emissions of nitrogen oxides decreased by 66 %, carbon monoxide by 70 %, non-methane volatile organic compounds by 54 % and methane by 26 %. 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.

Heavy metal emissions in Slovenia significantly decreased between 1990 and 2020. This can be largely attributed to the implementation of the EU legislation, improved surveillance and use of the best available technology. 

In Slovenia, emissions of persistent organic pollutants (polychlorinated biphenyl, polycyclic aromatic hydrocarbons, hexachlorobenzene, dioxins and furans) decreased between 1990-2021, primarily due to targeted legislation, improved control and use of best available technologies.

Projections show a reduction in SO2, NOx, NMVOC, NH3 and PM 2.5 emissions by 2030, mainly due to more strict legislation and implementing a number of sectoral policy measures. Reduction is inline with set targets for 2020 and 2030. For PM2.5, NMVOC and SO2 emissions in 2030 are only slightly lower than according to targets, so there is a possibility that targets will not be met. To avoid that, it is of great importance that trends are regularly monitored and if necessary additional measures are prepared.

The emission of primary particles, smaller than 10 µm (PM₁₀), particles smaller than 2.5 µm (PM_2.5) and all total suspended particles (TSP) have decreased in the period 2000 – 2021 in Slovenia by 21 %, 29 % and 20 %. The main source of emissions of particulate matter are households, mainly due to use of biomass for domestic heating.