Trends in emissions of greenhouse gases and pollutants from the transport sector have been balanced since 1990. More information on emissions trends from the transport sector in Slovakia.
Transport is a significant source of greenhouse gases and air pollutants. Despite improvements in vehicle engine efficiency over the past decade, road transport remains a major source of carbon dioxide (CO₂), nitrogen oxides (NOₓ), carbon monoxide (CO), particulate matter (PM), and copper emissions.
Trends in greenhouse gas emissions
CO₂ emissions from transport in Slovakia have shown a long-term upward trend, even though fuel consumption per kilometre has gradually decreased due to improved engine thermal efficiency and injection systems. Since 2000, the average fuel consumption of petrol and diesel vehicles has improved by approximately 20–30% due to higher thermal efficiency and more efficient injection systems. However, total annual fuel consumption continues to rise slightly, as vehicle kilometres travelled are increasing faster than consumption per kilometre is decreasing.
The SUV and heavy-duty vehicle segments show fuel consumption levels several tens of percent higher than compact models, and their growing market share partly offsets savings achieved in smaller categories. The use of alternative fuels (LPG, CNG) remains low, although they typically have 10–15% lower fuel consumption per kilometre compared to traditional fossil fuels. The share of biofuels in blends is increasing in line with legislation, but their impact on overall consumption is still small.
The CO₂ emission trend closely follows annual fuel consumption – if consumption increases, total CO₂ emissions also rise, and vice versa. Temporary slowdowns in fuel consumption growth, such as during the COVID-19 pandemic, briefly lowered emissions, but they rose again as traffic returned to pre-pandemic levels. Increasing demand for passenger and freight transport, along with insufficient enforcement of past emission standards, contributed to missed emission reduction targets.
Methane (CH₄) emissions from transport arise from incomplete fuel combustion, especially in modern engines operating under low load. Improved fuel injection, optimized combustion cycles, and specialized CH₄ oxidation catalysts have significantly reduced these emissions. N₂O forms in small amounts during high-temperature combustion; though catalytic converters help mitigate this, N₂O remains below 1% of transport GHG emissions.
Total greenhouse gas emissions
Trends in air pollutant emissions
Transport is a significant source of pollutant emissions in the Slovak Republic, primarily nitrogen oxides (NOₓ), carbon monoxide (CO), particulate matter (PM10, PM2.5), and organic compounds. The highest emissions occur in road transport, where traffic intensity, vehicle age, and technical condition are the determining factors. Emissions from transport contribute to the deterioration of air quality, smog formation, and secondary pollutants, and they have a substantial negative impact on human health and the environment.
Total pollutant emissions
NOx emission trends
NOₓ emissions in Slovakia have been decreasing over the long term, particularly after the introduction of Euro 5 and Euro 6 emission standards and the deployment of selective catalytic reduction (SCR) systems using urea (AdBlue). Total NOₓ emissions from transport dropped by around 60% compared to 2005, and by more than two-thirds from levels at the end of the last century.
Diesel combustion in road transport remains the main NOₓ source, accounting for roughly 70% of emissions. Gasoline engines contribute around 20%, and the remainder comes from gas, biofuel, and other alternative engines. Electrified rail and upgraded engines in buses and commercial vehicles are helping to reduce emissions, but older diesel vehicles and heavy trucks still dominate the emissions profile.
Measurements have shown that average NOₓ emissions from Euro 5 diesel engines (notably during the "Dieselgate" scandal) often fail to meet expectations, sometimes exceeding previous standard limits. This demonstrates that stricter limits alone are insufficient without enforcement and on-road monitoring.
Temporary fluctuations, such as those during mobility restrictions, led to noticeable but short-lived drops in NOₓ emissions. As normal traffic levels resumed, the downward trend returned to its slow decline. Without further technological innovations—such as improved SCR catalysts, material upgrades in engines, and broader deployment of electric and zero-emission transport—the rate of NOₓ reduction is unlikely to accelerate.
NMVOC emission trends
Emissions of non-methane volatile organic compounds (NMVOCs) from transport are mainly caused by petrol evaporation from fuel tanks and fuel systems. In previous years, these emissions declined significantly due to improvements in vehicle design and fuel system technology. Recently, however, a slight increase has been observed, linked to higher petrol consumption in road transport and rising average summer air temperatures, which intensify evaporation. As a result, the overall trend shows a renewed moderate increase in NMVOC emissions from this source.
In road transport, exhaust emissions still represent the largest share of NMVOCs from transport. However, fuel evaporation contributes significantly, especially during summer months, and now accounts for a larger portion of total road transport emissions than in the past. In addition to road transport, NMVOC emissions also arise from fuel combustion in rail, maritime, and air transport. These sources, however, represent a smaller share compared to road transport — in rail mainly from diesel locomotives, in shipping from small vessels, and in aviation from operations during take-off, landing, and ground handling. Overall, road transport remains the dominant source of NMVOC emissions in the transport sector.
Particulate matter emission trends
Particulate matter emissions in transport (PM₂.₅, PM₁₀, and total suspended particles – TSP) originate from both exhaust and non-exhaust sources within the transport sector. Currently, the main sources of these emissions in road transport are non-exhaust processes, primarily mechanical wear from tyres, brake systems, and road surfaces. However, exhaust emissions from diesel engines, especially older vehicles without effective filtration systems, still represent a significant share. The overall trend in particulate emissions from road transport has been declining over the long term, mainly due to advances in engine technologies, road surface improvements, and stricter emission standards. This decline, however, is slowing down, as non-exhaust sources are not yet regulated as strictly as exhaust emissions.
Road transport accounts for the largest share of total particulate emissions from transport — approximately 70–80% for PM₂.₅ and about 60–70% for PM₁₀ and TSP. Rail transport contributes a smaller share, generally below 5%, mainly from brake wear and diesel combustion in locomotives. In maritime transport, emissions arise primarily from the combustion of heavy fuels, especially in port areas, contributing around 10–15% of total PM emissions from transport. Aviation contributes mainly during ground operations, take-off, and landing, accounting for about 5–10% of total particulate emissions. Pipeline transport produces only negligible PM emissions, mostly from auxiliary combustion equipment, and its overall impact is minimal.
Overall, road transport remains the dominant source of particulate matter within the transport sector — primarily due to mechanical wear of components and combustion in older vehicles. Given the slower pace of reduction in non-exhaust emissions, their relative importance is expected to increase in the future within the overall PM emission profile from transport.
Particulate matter emission trends
Particulate matter emissions in transport (PM₂.₅, PM₁₀, and total suspended particles – TSP) originate from both exhaust and non-exhaust sources within the transport sector. Currently, the main sources of these emissions in road transport are non-exhaust processes, primarily mechanical wear from tyres, brake systems, and road surfaces. However, exhaust emissions from diesel engines, especially older vehicles without effective filtration systems, still represent a significant share. The overall trend in particulate emissions from road transport has been declining over the long term, mainly due to advances in engine technologies, road surface improvements, and stricter emission standards. This decline, however, is slowing down, as non-exhaust sources are not yet regulated as strictly as exhaust emissions.
Road transport accounts for the largest share of total particulate emissions from transport — approximately 70–80% for PM₂.₅ and about 60–70% for PM₁₀ and TSP. Rail transport contributes a smaller share, generally below 5%, mainly from brake wear and diesel combustion in locomotives. In maritime transport, emissions arise primarily from the combustion of heavy fuels, especially in port areas, contributing around 10–15% of total PM emissions from transport. Aviation contributes mainly during ground operations, take-off, and landing, accounting for about 5–10% of total particulate emissions. Pipeline transport produces only negligible PM emissions, mostly from auxiliary combustion equipment, and its overall impact is minimal.
Overall, road transport remains the dominant source of particulate matter within the transport sector — primarily due to mechanical wear of components and combustion in older vehicles. Given the slower pace of reduction in non-exhaust emissions, their relative importance is expected to increase in the future within the overall PM emission profile from transport.
Particulate matter emission trends
Particulate matter emissions in transport (PM₂.₅, PM₁₀, and total suspended particles – TSP) originate from both exhaust and non-exhaust sources within the transport sector. Currently, the main sources of these emissions in road transport are non-exhaust processes, primarily mechanical wear from tyres, brake systems, and road surfaces. However, exhaust emissions from diesel engines, especially older vehicles without effective filtration systems, still represent a significant share. The overall trend in particulate emissions from road transport has been declining over the long term, mainly due to advances in engine technologies, road surface improvements, and stricter emission standards. This decline, however, is slowing down, as non-exhaust sources are not yet regulated as strictly as exhaust emissions.
Road transport accounts for the largest share of total particulate emissions from transport — approximately 70–80% for PM₂.₅ and about 60–70% for PM₁₀ and TSP. Rail transport contributes a smaller share, generally below 5%, mainly from brake wear and diesel combustion in locomotives. In maritime transport, emissions arise primarily from the combustion of heavy fuels, especially in port areas, contributing around 10–15% of total PM emissions from transport. Aviation contributes mainly during ground operations, take-off, and landing, accounting for about 5–10% of total particulate emissions. Pipeline transport produces only negligible PM emissions, mostly from auxiliary combustion equipment, and its overall impact is minimal.
Overall, road transport remains the dominant source of particulate matter within the transport sector — primarily due to mechanical wear of components and combustion in older vehicles. Given the slower pace of reduction in non-exhaust emissions, their relative importance is expected to increase in the future within the overall PM emission profile from transport.
Other pollutants emission trends
Other air pollutants from transport, such as carbon monoxide (CO), sulfur dioxide (SO₂), ammonia (NH₃), heavy metals, and persistent organic pollutants, are of considerably lower significance in the emission inventory compared to the main monitored pollutants. Their share of total transport emissions is relatively small, and the transport sector contributes only marginally to national totals.
Emissions of carbon monoxide and sulfur dioxide have decreased significantly over the past decades, mainly due to technological advancements in combustion engines and the shift to low-sulfur fuels. Heavy metal emissions, such as copper and zinc, are primarily linked to the wear of vehicle components and remain relatively stable, with the highest values observed for copper from braking systems.
For other substances, such as ammonia or certain organic compounds, transport emissions are negligible compared to those from agriculture or industry. Overall, transport plays only a minor role in this group of pollutants, with emissions showing a stable or slightly declining trend.
Other pollutants emission trends
Other air pollutants from transport, such as carbon monoxide (CO), sulfur dioxide (SO₂), ammonia (NH₃), heavy metals, and persistent organic pollutants, are of considerably lower significance in the emission inventory compared to the main monitored pollutants. Their share of total transport emissions is relatively small, and the transport sector contributes only marginally to national totals.
Emissions of carbon monoxide and sulfur dioxide have decreased significantly over the past decades, mainly due to technological advancements in combustion engines and the shift to low-sulfur fuels. Heavy metal emissions, such as copper and zinc, are primarily linked to the wear of vehicle components and remain relatively stable, with the highest values observed for copper from braking systems.
For other substances, such as ammonia or certain organic compounds, transport emissions are negligible compared to those from agriculture or industry. Overall, transport plays only a minor role in this group of pollutants, with emissions showing a stable or slightly declining trend.
Particulate matter emission trends
Particulate matter emissions in transport (PM₂.₅, PM₁₀, and total suspended particles – TSP) originate from both exhaust and non-exhaust sources within the transport sector. Currently, the main sources of these emissions in road transport are non-exhaust processes, primarily mechanical wear from tyres, brake systems, and road surfaces. However, exhaust emissions from diesel engines, especially older vehicles without effective filtration systems, still represent a significant share. The overall trend in particulate emissions from road transport has been declining over the long term, mainly due to advances in engine technologies, road surface improvements, and stricter emission standards. This decline, however, is slowing down, as non-exhaust sources are not yet regulated as strictly as exhaust emissions.
Road transport accounts for the largest share of total particulate emissions from transport — approximately 70–80% for PM₂.₅ and about 60–70% for PM₁₀ and TSP. Rail transport contributes a smaller share, generally below 5%, mainly from brake wear and diesel combustion in locomotives. In maritime transport, emissions arise primarily from the combustion of heavy fuels, especially in port areas, contributing around 10–15% of total PM emissions from transport. Aviation contributes mainly during ground operations, take-off, and landing, accounting for about 5–10% of total particulate emissions. Pipeline transport produces only negligible PM emissions, mostly from auxiliary combustion equipment, and its overall impact is minimal.
Overall, road transport remains the dominant source of particulate matter within the transport sector — primarily due to mechanical wear of components and combustion in older vehicles. Given the slower pace of reduction in non-exhaust emissions, their relative importance is expected to increase in the future within the overall PM emission profile from transport.
Other pollutants emission trends
Other air pollutants from transport, such as carbon monoxide (CO), sulfur dioxide (SO₂), ammonia (NH₃), heavy metals, and persistent organic pollutants, are of considerably lower significance in the emission inventory compared to the main monitored pollutants. Their share of total transport emissions is relatively small, and the transport sector contributes only marginally to national totals.
Emissions of carbon monoxide and sulfur dioxide have decreased significantly over the past decades, mainly due to technological advancements in combustion engines and the shift to low-sulfur fuels. Heavy metal emissions, such as copper and zinc, are primarily linked to the wear of vehicle components and remain relatively stable, with the highest values observed for copper from braking systems.
For other substances, such as ammonia or certain organic compounds, transport emissions are negligible compared to those from agriculture or industry. Overall, transport plays only a minor role in this group of pollutants, with emissions showing a stable or slightly declining trend.
Other pollutants emission trends
Other air pollutants from transport, such as carbon monoxide (CO), sulfur dioxide (SO₂), ammonia (NH₃), heavy metals, and persistent organic pollutants, are of considerably lower significance in the emission inventory compared to the main monitored pollutants. Their share of total transport emissions is relatively small, and the transport sector contributes only marginally to national totals.
Emissions of carbon monoxide and sulfur dioxide have decreased significantly over the past decades, mainly due to technological advancements in combustion engines and the shift to low-sulfur fuels. Heavy metal emissions, such as copper and zinc, are primarily linked to the wear of vehicle components and remain relatively stable, with the highest values observed for copper from braking systems.
For other substances, such as ammonia or certain organic compounds, transport emissions are negligible compared to those from agriculture or industry. Overall, transport plays only a minor role in this group of pollutants, with emissions showing a stable or slightly declining trend.
Other pollutants emission trends
Other air pollutants from transport, such as carbon monoxide (CO), sulfur dioxide (SO₂), ammonia (NH₃), heavy metals, and persistent organic pollutants, are of considerably lower significance in the emission inventory compared to the main monitored pollutants. Their share of total transport emissions is relatively small, and the transport sector contributes only marginally to national totals.
Emissions of carbon monoxide and sulfur dioxide have decreased significantly over the past decades, mainly due to technological advancements in combustion engines and the shift to low-sulfur fuels. Heavy metal emissions, such as copper and zinc, are primarily linked to the wear of vehicle components and remain relatively stable, with the highest values observed for copper from braking systems.
For other substances, such as ammonia or certain organic compounds, transport emissions are negligible compared to those from agriculture or industry. Overall, transport plays only a minor role in this group of pollutants, with emissions showing a stable or slightly declining trend.
Other pollutants emission trends
Other air pollutants from transport, such as carbon monoxide (CO), sulfur dioxide (SO₂), ammonia (NH₃), heavy metals, and persistent organic pollutants, are of considerably lower significance in the emission inventory compared to the main monitored pollutants. Their share of total transport emissions is relatively small, and the transport sector contributes only marginally to national totals.
Emissions of carbon monoxide and sulfur dioxide have decreased significantly over the past decades, mainly due to technological advancements in combustion engines and the shift to low-sulfur fuels. Heavy metal emissions, such as copper and zinc, are primarily linked to the wear of vehicle components and remain relatively stable, with the highest values observed for copper from braking systems.
For other substances, such as ammonia or certain organic compounds, transport emissions are negligible compared to those from agriculture or industry. Overall, transport plays only a minor role in this group of pollutants, with emissions showing a stable or slightly declining trend.
Other pollutants emission trends
Other air pollutants from transport, such as carbon monoxide (CO), sulfur dioxide (SO₂), ammonia (NH₃), heavy metals, and persistent organic pollutants, are of considerably lower significance in the emission inventory compared to the main monitored pollutants. Their share of total transport emissions is relatively small, and the transport sector contributes only marginally to national totals.
Emissions of carbon monoxide and sulfur dioxide have decreased significantly over the past decades, mainly due to technological advancements in combustion engines and the shift to low-sulfur fuels. Heavy metal emissions, such as copper and zinc, are primarily linked to the wear of vehicle components and remain relatively stable, with the highest values observed for copper from braking systems.
For other substances, such as ammonia or certain organic compounds, transport emissions are negligible compared to those from agriculture or industry. Overall, transport plays only a minor role in this group of pollutants, with emissions showing a stable or slightly declining trend.
Other pollutants emission trends
Other air pollutants from transport, such as carbon monoxide (CO), sulfur dioxide (SO₂), ammonia (NH₃), heavy metals, and persistent organic pollutants, are of considerably lower significance in the emission inventory compared to the main monitored pollutants. Their share of total transport emissions is relatively small, and the transport sector contributes only marginally to national totals.
Emissions of carbon monoxide and sulfur dioxide have decreased significantly over the past decades, mainly due to technological advancements in combustion engines and the shift to low-sulfur fuels. Heavy metal emissions, such as copper and zinc, are primarily linked to the wear of vehicle components and remain relatively stable, with the highest values observed for copper from braking systems.
For other substances, such as ammonia or certain organic compounds, transport emissions are negligible compared to those from agriculture or industry. Overall, transport plays only a minor role in this group of pollutants, with emissions showing a stable or slightly declining trend.
Other pollutants emission trends
Other air pollutants from transport, such as carbon monoxide (CO), sulfur dioxide (SO₂), ammonia (NH₃), heavy metals, and persistent organic pollutants, are of considerably lower significance in the emission inventory compared to the main monitored pollutants. Their share of total transport emissions is relatively small, and the transport sector contributes only marginally to national totals.
Emissions of carbon monoxide and sulfur dioxide have decreased significantly over the past decades, mainly due to technological advancements in combustion engines and the shift to low-sulfur fuels. Heavy metal emissions, such as copper and zinc, are primarily linked to the wear of vehicle components and remain relatively stable, with the highest values observed for copper from braking systems.
For other substances, such as ammonia or certain organic compounds, transport emissions are negligible compared to those from agriculture or industry. Overall, transport plays only a minor role in this group of pollutants, with emissions showing a stable or slightly declining trend.
Other pollutants emission trends
Other air pollutants from transport, such as carbon monoxide (CO), sulfur dioxide (SO₂), ammonia (NH₃), heavy metals, and persistent organic pollutants, are of considerably lower significance in the emission inventory compared to the main monitored pollutants. Their share of total transport emissions is relatively small, and the transport sector contributes only marginally to national totals.
Emissions of carbon monoxide and sulfur dioxide have decreased significantly over the past decades, mainly due to technological advancements in combustion engines and the shift to low-sulfur fuels. Heavy metal emissions, such as copper and zinc, are primarily linked to the wear of vehicle components and remain relatively stable, with the highest values observed for copper from braking systems.
For other substances, such as ammonia or certain organic compounds, transport emissions are negligible compared to those from agriculture or industry. Overall, transport plays only a minor role in this group of pollutants, with emissions showing a stable or slightly declining trend.
Other pollutants emission trends
Other air pollutants from transport, such as carbon monoxide (CO), sulfur dioxide (SO₂), ammonia (NH₃), heavy metals, and persistent organic pollutants, are of considerably lower significance in the emission inventory compared to the main monitored pollutants. Their share of total transport emissions is relatively small, and the transport sector contributes only marginally to national totals.
Emissions of carbon monoxide and sulfur dioxide have decreased significantly over the past decades, mainly due to technological advancements in combustion engines and the shift to low-sulfur fuels. Heavy metal emissions, such as copper and zinc, are primarily linked to the wear of vehicle components and remain relatively stable, with the highest values observed for copper from braking systems.
For other substances, such as ammonia or certain organic compounds, transport emissions are negligible compared to those from agriculture or industry. Overall, transport plays only a minor role in this group of pollutants, with emissions showing a stable or slightly declining trend.
Other pollutants emission trends
Other air pollutants from transport, such as carbon monoxide (CO), sulfur dioxide (SO₂), ammonia (NH₃), heavy metals, and persistent organic pollutants, are of considerably lower significance in the emission inventory compared to the main monitored pollutants. Their share of total transport emissions is relatively small, and the transport sector contributes only marginally to national totals.
Emissions of carbon monoxide and sulfur dioxide have decreased significantly over the past decades, mainly due to technological advancements in combustion engines and the shift to low-sulfur fuels. Heavy metal emissions, such as copper and zinc, are primarily linked to the wear of vehicle components and remain relatively stable, with the highest values observed for copper from braking systems.
For other substances, such as ammonia or certain organic compounds, transport emissions are negligible compared to those from agriculture or industry. Overall, transport plays only a minor role in this group of pollutants, with emissions showing a stable or slightly declining trend.
Other pollutants emission trends
Other air pollutants from transport, such as carbon monoxide (CO), sulfur dioxide (SO₂), ammonia (NH₃), heavy metals, and persistent organic pollutants, are of considerably lower significance in the emission inventory compared to the main monitored pollutants. Their share of total transport emissions is relatively small, and the transport sector contributes only marginally to national totals.
Emissions of carbon monoxide and sulfur dioxide have decreased significantly over the past decades, mainly due to technological advancements in combustion engines and the shift to low-sulfur fuels. Heavy metal emissions, such as copper and zinc, are primarily linked to the wear of vehicle components and remain relatively stable, with the highest values observed for copper from braking systems.
For other substances, such as ammonia or certain organic compounds, transport emissions are negligible compared to those from agriculture or industry. Overall, transport plays only a minor role in this group of pollutants, with emissions showing a stable or slightly declining trend.
Other pollutants emission trends
Other air pollutants from transport, such as carbon monoxide (CO), sulfur dioxide (SO₂), ammonia (NH₃), heavy metals, and persistent organic pollutants, are of considerably lower significance in the emission inventory compared to the main monitored pollutants. Their share of total transport emissions is relatively small, and the transport sector contributes only marginally to national totals.
Emissions of carbon monoxide and sulfur dioxide have decreased significantly over the past decades, mainly due to technological advancements in combustion engines and the shift to low-sulfur fuels. Heavy metal emissions, such as copper and zinc, are primarily linked to the wear of vehicle components and remain relatively stable, with the highest values observed for copper from braking systems.
For other substances, such as ammonia or certain organic compounds, transport emissions are negligible compared to those from agriculture or industry. Overall, transport plays only a minor role in this group of pollutants, with emissions showing a stable or slightly declining trend.
Other pollutants emission trends
Other air pollutants from transport, such as carbon monoxide (CO), sulfur dioxide (SO₂), ammonia (NH₃), heavy metals, and persistent organic pollutants, are of considerably lower significance in the emission inventory compared to the main monitored pollutants. Their share of total transport emissions is relatively small, and the transport sector contributes only marginally to national totals.
Emissions of carbon monoxide and sulfur dioxide have decreased significantly over the past decades, mainly due to technological advancements in combustion engines and the shift to low-sulfur fuels. Heavy metal emissions, such as copper and zinc, are primarily linked to the wear of vehicle components and remain relatively stable, with the highest values observed for copper from braking systems.
For other substances, such as ammonia or certain organic compounds, transport emissions are negligible compared to those from agriculture or industry. Overall, transport plays only a minor role in this group of pollutants, with emissions showing a stable or slightly declining trend.
Other pollutants emission trends
Other air pollutants from transport, such as carbon monoxide (CO), sulfur dioxide (SO₂), ammonia (NH₃), heavy metals, and persistent organic pollutants, are of considerably lower significance in the emission inventory compared to the main monitored pollutants. Their share of total transport emissions is relatively small, and the transport sector contributes only marginally to national totals.
Emissions of carbon monoxide and sulfur dioxide have decreased significantly over the past decades, mainly due to technological advancements in combustion engines and the shift to low-sulfur fuels. Heavy metal emissions, such as copper and zinc, are primarily linked to the wear of vehicle components and remain relatively stable, with the highest values observed for copper from braking systems.
For other substances, such as ammonia or certain organic compounds, transport emissions are negligible compared to those from agriculture or industry. Overall, transport plays only a minor role in this group of pollutants, with emissions showing a stable or slightly declining trend.
Other pollutants emission trends
Other air pollutants from transport, such as carbon monoxide (CO), sulfur dioxide (SO₂), ammonia (NH₃), heavy metals, and persistent organic pollutants, are of considerably lower significance in the emission inventory compared to the main monitored pollutants. Their share of total transport emissions is relatively small, and the transport sector contributes only marginally to national totals.
Emissions of carbon monoxide and sulfur dioxide have decreased significantly over the past decades, mainly due to technological advancements in combustion engines and the shift to low-sulfur fuels. Heavy metal emissions, such as copper and zinc, are primarily linked to the wear of vehicle components and remain relatively stable, with the highest values observed for copper from braking systems.
For other substances, such as ammonia or certain organic compounds, transport emissions are negligible compared to those from agriculture or industry. Overall, transport plays only a minor role in this group of pollutants, with emissions showing a stable or slightly declining trend.
Other pollutants emission trends
Other air pollutants from transport, such as carbon monoxide (CO), sulfur dioxide (SO₂), ammonia (NH₃), heavy metals, and persistent organic pollutants, are of considerably lower significance in the emission inventory compared to the main monitored pollutants. Their share of total transport emissions is relatively small, and the transport sector contributes only marginally to national totals.
Emissions of carbon monoxide and sulfur dioxide have decreased significantly over the past decades, mainly due to technological advancements in combustion engines and the shift to low-sulfur fuels. Heavy metal emissions, such as copper and zinc, are primarily linked to the wear of vehicle components and remain relatively stable, with the highest values observed for copper from braking systems.
For other substances, such as ammonia or certain organic compounds, transport emissions are negligible compared to those from agriculture or industry. Overall, transport plays only a minor role in this group of pollutants, with emissions showing a stable or slightly declining trend.
Emission trends by categories and by fuel types
Trends in greenhouse gas and air pollutant emissions from the transport sector by transport mode, and trends in greenhouse gas emissions from road transport by fuel type.
In road transport, diesel consumption dominates, consistently accounting for around two-thirds to three-quarters of total fuel use. Gasoline makes up about one-quarter. Biofuels, which are blended with gasoline and diesel as required by law, represent around 5–7%. LPG and CNG are marginal, together making up less than 2%. Other fossil fuels are negligible at under 1%. This fuel consumption profile has remained fairly stable in recent years, though biofuel use is gradually increasing due to policy requirements.
Emissions by category
The largest share of emissions comes from the combustion of diesel (70%), petrol (20%), and natural gas (2%), while biofuels also contribute significantly in terms of pollutant emissions (6.3%). Aviation fuels and LPG together account for about 1.7% of total fuel consumption in transport. The high share of diesel results from its use across multiple transport modes, including road, rail, and maritime transport. The share of biomass-based fuels increases each year, driven by the obligation to blend biofuels into fuels used in road and rail transport.