Vehicle-related particulate matter (PM) emissions may arise from both exhaust and non-exhaust mechanisms, such as brake wear, tyre wear, and road pavement abrasion, each of which may be emitted directly and indirectly through resuspension of settled road dust. Several researchers have indicated that the proportion of PM2.5 attributable to vehicle traffic will increasingly come from non-exhaust sources. Currently, very little empirical data is available to characterise tyre and road wear particles (TRWP) in the PM2.5 fraction. As such, this study was undertaken to quantify TRWP in PM2.5 at roadside locations in urban centres including London, Tokyo and Los Angeles, where vehicle traffic is an important contributor to ambient air PM.

The sources of PM2.5 vary spatially with long-range transport sources generated mainly from secondary PM and local sources generated mainly from combustion processes associated with industrial operations and road transport. A recent literature review of various PM2.5 local source apportionment studies conducted in 51 different countries concluded that 25% of urban ambient air pollution from PM2.5 is contributed by traffic, 15% by industrial activities, 20% by domestic fuel burning, 22% from unspecified sources of human origin, and 18% from natural dust and salt. Both primary and secondary PM were accounted for in the analysis and the contribution was dependent on the source. For example, the researchers generally apportioned traffic sources by primary PM emissions and the unspecified sources of human origin based on secondary PM emissions. PM2.5 also varies spatially and temporally.

Over the last 20 years, environmental agencies worldwide have enacted regulations, including those for motor vehicles, in an effort to reduce the emissions of PM2.5; and, indeed, a decline is observable in areas with established monitoring networks. For example, in the US, from 2000 to 2016, the nationwide levels of PM2.5 have decreased 42%; with the vast majority of the measurements below the national standard of 12 μg/m3 since 2012. In Europe (EU-28), the emissions of primary PM2.5 decreased by 16% from 2003–2012.

Vehicle-related PM emissions may arise from both exhaust and non-exhaust mechanisms, such as brake wear, tyre wear, and road pavement abrasion. Several researchers have indicated that the proportion of vehicle traffic attributable to PM2.5 will come increasingly from non-exhaust sources, due to additional regulations limiting vehicle exhaust emissions. The current and future contributions of non-exhaust sources have been evaluated primarily through indirect methods such as various receptor-modelling approaches or air dispersion modelling paired with emission inventories. A recent literature review of non-exhaust emissions reported more than 250 estimates of contribution to ambient air PM.

When tyres interact with the roadway surface, tyre and road wear particles (TRWP) are produced, containing both the tread rubber and embedded road material.

The contribution of tyre wear to ambient PM10 and PM2.5 has been estimated to be between 0.8–8.5% and 1–10% by mass respectively, although the data are sparse and most estimates are indirectly calculated with only a few observational studies. Given the complex composition of the TRWP, a variety of analytical techniques have been proposed, but the only ones with sufficient specificity to the particles are chemical markers associated with the tread rubber, which include monomers styrene and 1,3-butadiene, as well as the dimers vinylcyclohexene and dipentene. Given the predicted increases in non-exhaust emission contributions to PM2.5, the current study was undertaken to measure levels of TRWP in PM2.5 in urban environments where traffic-related PM is significant. Sample locations were chosen to be representative of likely human exposure in various roadside microenvironments. To facilitate comparison to our earlier work and estimates published by others, we present mass-based concentrations and relative contribution to PM2.5 for both TRWP and tread for each sampling location.

Materials, methods

To select the cities for inclusion in this study, data were assembled for large urban areas in Europe, Asia, and the United States. A selection matrix was developed to identify cities based on several criteria including, levels of ambient PM2.5, traffic loads, population density, and local regulatory actions to reduce PM2.5.

In Europe, five cities were considered, including Barcelona, London, Milan, Paris and Rome, with London being ultimately selected. In Japan, six cities were considered, including Nagoya, Osaka, Tokyo, Saitama City, Yokohama, and Kyoto, with Tokyo being ultimately selected. In the US, three cities were considered, including Atlanta, Los Angeles and New York City, with Los Angeles ultimately selected.

Within each city, the site selection criteria included the presence of identifiable traffic and historical presence of high PM2.5 levels where possible. All air samples were collected near the roadside, and the distance from road was dictated by logistical constraints such as security of the equipment and available power sources. For London only, an urban background site was also included.

The analytical technique is based on the characteristic fragments generated by the thermal decomposition of the tyre tread polymers that include styrene butadiene rubber (SBR), butadiene rubber (BR) and natural rubber (NR). Briefly, the method consists of the following steps: the tread rubber polymers in environmental samples undergo thermal decomposition at 670 °C by Curie-point pyrolysis; next, the thermal decomposition products are separated using a gas chromatograph (GC); and finally, the pyrolysis fragments are quantified with mass spectrometry (MS).

The data were evaluated using the Analysis of Variance (ANOVA) and regression models to identify differences among the cities and trends in determinants of TRWP concentrations between sampling locations and cities.

Results

In total 80 samples were analysed, and the TRWP detection frequencies ranged from 0–100%. The lowest detection frequencies were recorded in Los Angeles, with four of the six locations showing no detections. The total ambient PM2.5 levels were low in Los Angeles during sampling days, which was surprising due to the historical levels recorded in the area for the same time of year.

The TRWP made a small contribution to total ambient PM2.5 levels, representing 0.1–0.68% of the total PM2.5 across all locations. The range of concentrations of TRWP were 0.012–0.29 μg/m3 in London, 0.010–0.1 μg/m3 in Tokyo, and 0.004–0.072 μg/m3 in Los Angeles. The highest concentrations were recorded at the Blackwall Tunnel Approach in London (mean 0.104 μg/m3 and range (0.03–0.29 μg/m3)) where significant braking activity occurs before the tunnel portal which creates more tyre wear abrasion than constant speed driving.

The highest TRWP PM2.5 concentration measured in Tokyo was at the Kawasaki Industrial Road location, which had the highest traffic count of the Tokyo sites. In both Tokyo and London, the traffic composition was dominated primarily by passenger car and light duty vehicle traffic, with truck traffic generally comprising less than 20% of the total traffic. One exception was Kawaskai Industrial Road, where the truck traffic accounted for nearly 43% of the traffic.

Uncertainties

The data generated from this research provide an initial observation of TRWP in PM2.5 using methods that are specific to tyre tread, however, they are site specific and may not be applicable more broadly given the small sample size and consequent low statistical power. The calculation of the TRWP concentration involves the assumption of 50% of the polymer in the tread and 50% of tread in the TRWP. However, the 50% assumption of tread in the TRWP is based on the characterisation of bulk TRWP in the size range of 0–150 μm. As such, the composition of the <10 μm fraction has not been specifically characterized.

It is currently unknown if the use of the 50% tread assumption overestimates or underestimates that composition in the <10 μm particles. Previously, the tyre wear contribution to the PM2.5 fraction was evaluated using Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) and the researchers concluded that there was both a pavement and tread component, although the researchers did not have a quantitative estimate of the amounts. More recently, roadside airborne particulate in the 10–80 μm range was characterised using SEM EDX and the researchers concluded that the amount of pavement encrustation of the surface area of the ‘tyre core’ (i.e., tread) ranged from approximately 10% to more than 50%. As such, more research may be needed to refine TRWP composition in the PM10 and PM2.5 fractions.

Bridgestone will supply tailored-made tyres for Lamborghini’s Huracán STO, which will be launched in 2021.

Bridgestone ensured the high-performance tyre can maximise the Huracán STO’s traction, handling, control, and extreme overall performance.

Key to the tyre’s success in maximising the super sports car’s performance is the combination of pattern and cavity design. The Potenza tyres apply an asymmetric tread design for enhanced steering response and cornering stability, and an internal crown structure that distributes footprint pressure evenly when cornering.

As well as the road-focused, custom-developed Potenza fitment, Bridgestone will also be providing a track-oriented, road-homologated version of the tyre that applies “race” technologies to maximise the vehicle’s track performance, especially in dry conditions.

Steven De Bock, VP Consumer Replacement and OE at Bridgestone EMIA, said, “It’s been a pleasure for our team to work so closely with Lamborghini for the first time, and on such an exciting project. The Huracán STO is an incredible piece of engineering that deserves a custom tyre that can fulfill its full potential. I can proudly say that Bridgestone has delivered such a high-performance tyre. It has been fantastic for the team to have worked on a project that is at the forefront of technology in so many ways.”

Hankook, one of the major global tyre brands, has started testing and development operations at its new ultra modern facility in Spain.

The testing facility has been set up on the premises of the Applus+ IDIADA Group and can also cater to European premium car manufacturers that have their own demanding tyre tests. The facility is completely automated and will host a 20-member team from the Spanish testing centre, which is affiliated to the Hankook Europe Technical Centre.

Klaus Krause, Head of European Research and Development Centre, said, "With the further expansion of our testing capacities in Spain, we are reaching the next level together with our local partner Applus+ IDIADA."

He also added, "We are confident that the newly installed testing facilities in particular will significantly improve our efforts to provide the best tyre testing conditions and services to our employees and customers. In addition, we will also be able to conduct significantly more tests on site." (TT)

ASCENSO introduced a construction tyre - BLB 730- which is used for boom lift vehicles used in construction and other industries. It comes with several features that cater to the unique needs of aerial lifting equipment.

The BLB 730 tyre is available in different sizes to fit various boom lift vehicles. This range of sizes provides versatility and compatibility with different types of aerial lift work platforms.

“ASCENSO's BLB 730 tyre is a significant advancement in specialised equipment for the construction industry. It focuses on load capacity, stability, traction, and durability to improve the performance and safety of boom lift vehicles. Whether working at heights or manoeuvring on tough terrains, this tyre offers reliability and durability for efficient operations,” said the company in a statement.

The BLB 730 tyre is built to handle heavy loads and stabilise boom lift vehicles. It has solid lugs and a more extended shoulder design, which ensures good traction and prevents slipping during operation. This is important for safely carrying heavy weights at high elevations. ASCENSO has used a special rubber compound in making the BLB 730 tyre, making it durable and long-lasting, resulting in less downtime and more productivity on construction sites.

To make the tyre even better, the company has optimised its inner volume to reduce tyre fill consumption, reducing the risk of tyre punctures, minimising the need for maintenance, and keep the vehicles running smoothly.

Falken Tyre Europe is an official IHF Men's World Championship 2023 partner for the upcoming tournament, the company has announced. The tournament is taking place at nine venues in Sweden and Poland from 11-29 January, 2023. Falken Tyre claims that the partnership was organised by the sports marketing agency SPORTFIVE. SPORTFIVE is responsible for exclusive marketing and media rights for all IHF World Championships until 2031.

Falken Tyre claims that this is its second agreement with the International Handball Federation. In addition to title and logo rights (Official IHF Men's World Championship 2023 Partner), the company has also secured advertising rights, including the Falken logo in each goal and centre circle of the courts, as well as the presence of Falken branding in the official tournament social media communications and print materials. According to Falken Tyre, this is complemented by 30-second video ads that will be shown on the big screens in the nine sports halls before the start of each match and at half-time.

Sharing his views, Robert Müller von Vultejus, Chief Growth Officer at SPORTFIVE, said, “With Falken, the IHF World Handball Championships have secured a great partner who is positioned with far-reaching influence in the relevant core markets. We are delighted to have been able to bring two global partners together for one of the most exciting sporting events of next year.”

Markus Bögner, COO and President of Falken Tyre Europe GmbH, explained, “Handball isn’t just of great importance in Europe, but all over the world, which has led us to partake in this top-level tournament once again. The fact that the international tournament is taking place in countries that are among our core markets is another great reason for our involvement. We can also look back on a long partnership with our colleagues at SPORTFIVE, who always offers us excellent opportunities that are an excellent fit for the Falken brand, which stands for enthusiasm, performance and achievement.”