Air pollution and Air quality
VTI conducts research on the transport sector’s contribution to air pollution through field measurements and laboratory studies. An important area of research is wear particles from roads and railways, where we study the properties and formation mechanisms of these particles. The aim is to understand whether—and if so, why—the particles have negative health effects and how emissions can be reduced.
A unique piece of equipment used in this research is VTI’s road simulator, which enables us to measure and sample wear particles from road and tire wear without influence from other sources. This is a crucial prerequisite for being able to investigate the mechanisms of particle formation and their characteristics, and for collecting samples for toxicological studies. Studies conducted using the road simulator mainly focus on various combinations of tires and road surfaces, with the goal of examining how different properties of pavement or tires affect particle emissions and characteristics. The results can help in selecting road surfaces and tires with properties that reduce emissions and the proportion of toxic particles.
Since airborne particle levels are also influenced by the resuspension of dust from the road surface, VTI has developed a sampling device called the Wet Dust Sampler (WDS), which allows sampling and analysis of the road dust reservoir on the surface. This helps evaluate the effectiveness of various dust mitigation measures and how the amount and properties of road dust are affected. The WDS has been widely used in various research and development projects and has also been manufactured and sold to both Norway and Finland.
VTI also carries out field measurements of particles in both road and railway environments. Rail-related wear particles are often found in very high concentrations in tunnel environments, are relatively small in size, and contain high levels of metals. This has increased interest in their potential health risks. VTI has therefore carried out several projects examining the properties and health risks of rail-related aerosol particles, including studies at the underground platforms at Arlanda Airport and at several above-ground station environments.
Microplastics from both tires and road surfaces are also a research area relevant to air quality, as many of these particles are small enough to contribute to the content of inhalable airborne particles. This research area is described in more detail on this page (link).
Since particle research requires broad expertise as well as expensive equipment and analytical methods, VTI researchers collaborate with several universities and other research institutes.
Photo: Michael Norman, SLB-analys.
VTI's particle instruments are:
- RP TEOM (Tapered element oscillating microbalance) – measurements of PM10 or PM2,5
- TSI DustTrak (2 units) – laser-based monitors that are fast, compact, and battery-operated, measuring PM10, PM4, PM2.5 or PM1.
- TSI APS (aerodynamic particle sizer) – aerosol size distribution between ca 0,5–18 µm.
- TSI SMPS (scanning mobility particle sizer) – aerosol size distribution between ca 10 nm–0,5 µm
- TSI NAS (nanometer aerosol sampler) – sampling of nanosized particles for analyses
- Fidas AQguard (2 pcs) optical instruments that provide PM1, PM2.5, PM4, PM10 and size distributions with 1 s time resolution.
- Ecotech Microvol (2 pcs) programmable samplers for PM10 or PM2.5 on 47 mm filters.
- Ecotech high volume sampler – sampling of large amounts of PM10 for e.g. toxicology
When the instruments are not booked for projects, we are happy to lend or rent them out for short periods to current or prospective research colleagues.
VTI also has an own-developed equipment for road dust sampling called the Wet Dust Sampler (WDS), which is used in Sweden, Norway and Finland.
VTI has also developed its own samplers in the air quality field:
- Wet Dust Sampler (WDS) II and III – a water-based device for sampling dust on the road surface. The dust can then be analyzed for quantity per area, size distribution, and chemical composition
- Duster II – used to study dust resuspension from a road surface
VTI Road Simulator described in more detail
The Wet Dust Sampler, WDS described in more detail
(WDS II and III)
NEEVE
Acronym for “Innovative technologies to monitor and reduce Non-Exhaust Emissions, particles and microplastics of VEhicles and pavements to improve air quality and human health”. This is a Life project led by the University of Seville and runs from 2023–2028. More information: https://www.neeve.eu
RoadMap
A project funded by the Centre for Road Technology (KCV). It aims to study the emissions, properties, and toxicity of particles from wear of various road paving materials generated in a laboratory environment. Led by Lund University of Technology.
Analysis of Toxicity and Microplastics in Airborne Particles
In this project, funded by the Swedish Transport Administration, the seasonal variation in quantity, composition (with a focus on microplastics), and toxicity of airborne particles is studied at two measurement sites: one in central Stockholm and one along a rural highway. The project is conducted in collaboration with Lund University of Technology, SLB-analys, and Particle Vision.
LEON-T
(completed)
An EU project in collaboration with IDIADA, Ford, Audi, JRC, RIVM, TNO to study particle and noise emissions from tires, propose a testing method for tire wear, and develop low-noise truck tires. More info: https://www.leont-project.eu
WeaRS
(completed)
In collaboration with IVL and commissioned by the Swedish Transport Administration, a new method was developed to measure wear particle emissions from passing vehicles. WDS was used to define road dust levels on test surfaces during development.
NorDust II
(completed)
A Nordic collaboration to improve understanding of how road dust emissions can be reduced and better modeled. Field studies provided data for improved parameterization and further development of the Nordic emission model NORTRIP. The project was funded by NordFoU and involved MetNorway (Norway), NILU (Norway), Metropolia (Finland), SYKE (Finland), SLBanalys (Sweden), and the University of Iceland.
uCARe
(completed)
A Horizon 2020 project funded by the EU, focusing on how car owners can reduce their emissions through better understanding of driving behavior and vehicle/component maintenance. The project ran from 2019–2022. VTI worked on wear particle emissions and research related to behavior and psychology.
The Intersection Project
(completed)
Funded by BVFF, this project aimed to investigate how air quality in intersections differs from that on road links. Air quality and traffic flow measurements were carried out in Stockholm.
Indicative Method for Assessing Pavement PM10 Emissions
Funded by BVFF, this project examined whether lab methods developed to test studded tire wear on pavement samples could also be used for preliminary assessment of PM10-emitting properties.
WearTox II
(completed)
In the WearTox II project, funded by the Swedish Transport Administration, the toxic properties of wear particles from road surfaces using different aggregate materials were studied. Lund University of Technology, Linköping University, and CBI (Cement and Concrete Institute) contributed expertise in aerosol generation, toxicology, and geology. The project also included a smaller study funded by the Dutch RIVM, where brake particles were sampled at KTH and used in the same toxicological experiments. This was a follow-up to the WearTox project reported in 2005.
Publication examples on air pollution and air quality:
NORDUST - Nordic Road Dust Project. (2019, DiVA)
Physical and chemical properties of non-exhaust particles generated from wear between pavements and tyres (2020, DiVA)
Wet Dust Sampler: a Sampling Method for Road Dust Quantification and Analyses (2019, DiVA)
On particulate emissions from moving trains in a tunnel environment. (2016, DiVA)
PM10 emission effects of new studded tyre regulations (2017, Scientific Press)