Traffic emissions per vehicle km continue to decrease
The EU is striving to become the first climate-neutral continent, with the ambition to achieve climate-neutrality by 2050. These efforts include reducing emissions and improving air quality, and good progress has been made over the past 20 to 30 years.
A large proportion of these pollutants are due to traffic and transport. Over the years, the EU has introduced various directives and regulations setting ever stricter emissions standards for new vehicles, to reduce emissions at the source. These regulations apply to GHG emissions as well as particulate matter.
In the Netherlands, the Environmental Data Compendium[1] monitors and publishes data on a wide range of indicators. It is interesting to see the downward trends in vehicle emissions, despite an increase in vehicle kilometres.
Although the total number of vehicle kilometres has increased since 1990, Nitrous Oxide (NOx) and Particulate Matter (PM10) emissions have decreased steadily over the years. CO2 emissions initially increased until 2006 when these emissions started to decline.
Road traffic volume trends and environmental pressure (1990-2018)
Details of NOx and PM10 emissions traceable to transport
We can attribute these decreases to increasingly stringent European emission requirements imposed on new vehicles. The Environmental Data Compendium also publishes separate data on NOx and PM10 emissions arising from passenger and goods transport. In the following charts we see that emissions per vehicle kilometre are significantly lower in 2022, the most recent data available, than in 2004, the start date of this data set.
NOx emissions per vehicle km on the decrease
The average emissions per kilometre of two substances that determine air quality, nitrogen oxides (NOx) and particulate matter with a diameter smaller than 10 µm (PM10), fell by 61% and 62% respectively compared to 2004.
The following chart shows these emissions for passenger and goods vehicles separately.
Nitrogen oxides (NOx) emissions per vehicle km for road traffic (2004-2022)
Average emissions per vehicle kilometre of nitrogen oxides (NOx) from passenger transport vehicles have fallen by 64% since 2004. The lower emissions of nitrogen oxides are due to the introduction of increasingly cleaner engines.
Average emissions per kilometre by goods transport vehicles have also fallen sharply, by 61%. This is mainly due to technical measures in diesel engines of heavy goods vehicles (exhaust gas recirculation and selective catalytic reduction). Strict emission standards have been in force for freight traffic since 2014, making new goods vehicles significantly cleaner than previous generations.
Downward trend in PM10 emissions per vehicle kilometre
Particulate matter pollution (PM10) is defined as airborne particles of less than 10 µm in diameter. Road traffic emissions include tiny particles of soot resulting from diesel combustion and particles arising from wear on the road surface and vehicle tyres and brakes.
The data shows that since 2004, average emissions of particulate matter PM10 per kilometre by passenger vehicles have fallen by 53%. The introduction of particulate filters in diesel vehicles built after 2000 is the main reason for the sharp reduction.
Since 2004, average emissions per vehicle kilometre from goods transport have also fallen sharply, by 71%.
Particulate matter (PM10) emissions per vehicle km for road traffic (2004-2022)
Source: CLO (Environmental Data Compendium). Adapted from Emissions per vehicle km and Road traffic: volume trends and environmental pressure