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.

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Toyo Tire Corporation said Mitsubishi Corporation has ceased to be a major shareholder after tendering its entire holding through a treasury share buyback, ending its status as the company’s largest shareholder.

The change took effect on 10^th August , 2026, following Toyo Tire’s acquisition of its own shares through off-auction trading (ToSTNeT-3). Mitsubishi tendered all its shares, excluding less than one unit, as part of the transaction.

As a result, Mitsubishi is no longer classified as a major shareholder or associated company of Toyo Tire, the company said.

Before the transaction, Mitsubishi held 30,822,206 shares, equivalent to 20.07 percent of total voting rights, and ranked as the largest shareholder. Following the change, its holding has effectively been reduced to zero.

The move follows Toyo Tire’s earlier announcement on August 7, 2026 regarding the termination of its capital and business alliance with Mitsubishi, alongside plans to repurchase its own shares.

Toyo Tire said the change would have no impact on its consolidated financial results.

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Linglong Tire has become the first Chinese tyre manufacturer to join the Global Data Service Organization (GDSO) as a full member, marking a step in the industry’s efforts to standardise and exchange tyre-related data globally.

The company joins the non-profit body as its fourteenth member. GDSO was established in January 2022 by Bridgestone, Continental, Goodyear, Michelin and Pirelli to facilitate the digital exchange of tyre data and develop common standards across the sector.

Moh Wahi, Head Of Truck And Bus Tyre Development at Linglong Europe, said: "By joining the GDSO as a Full Member and providing reliable data, we want to be the first Chinese tyre manufacturer to make a positive contribution to the further development of the tire industry and set new standards for the efficient processing of tire data in the digital age."

Riccardo Giovannotti, Secretary General of GDSO, said: "With Linglong Tire as a Full Member, GDSO is gaining one of the leading Chinese tire companies which is committed to digitalization and sustainability in the industry. Together, we will further make progress in developing standards for data processing and future-oriented solutions."

Shandong Linglong Tire Co., Ltd., founded in 1975, operates seven research and development centres globally and employs almost 20,000 people. The company runs nearly 200,000 sales outlets and exports products to 175 countries.

It supplies tyres to more than 200 production bases for over 60 automakers and has manufacturing facilities across China, Thailand and Serbia, with plans to expand further overseas.

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TyreSafe, UK’s charity dedicated to raising tyre safety awareness, has joined forces with Sussex Police’s Road Safety Team to introduce a pioneering digital reference tool for frontline officers. The initiative equips police with immediate, device-accessible tyre safety data during roadside stops.

Developed as a local pilot, the application enables consistent vehicle examinations and improves driver communication regarding tyre dangers. It offers specific checklists for diverse vehicle categories, including motorcycles, cars, heavy goods vehicles, light commercial vans and towed trailers. The system further incorporates guidance on part-worn tyres, common queries and educational talking points.

Following its Sussex trial, the programme holds potential for nationwide adoption across UK police forces. This deployment underscores Sussex Police’s dedication to roadway innovation and reinforces the essential contribution of proper tyre maintenance to overall public safety.

Stuart Lovatt, TyreSafe Chair, said, “This partnership with Sussex Police is a landmark moment for tyre safety enforcement and education. By putting reliable, accessible tyre safety guidance directly into the hands of frontline officers, we can ensure safer vehicles on our roads and help prevent avoidable collisions and breakdowns. Sussex is leading the way, and we hope this model will soon be adopted nationally.”

Superintendent Jo Grantham, Head of Roads Policing, Sussex Police, said, “Our officers are committed to keeping road users safe, and having instant access to this tyre safety resource makes a real difference on the ground. It supports enforcement while also giving us the tools to educate drivers more effectively. We’re proud to be working with TyreSafe on this project and to be the first police force in the country to pilot it.”

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The UK Towing Safety Alliance (UKTSA) has published a comprehensive four-year analysis of incident data from National Highways’ Strategic Road Network, covering 2022 to 2025. The findings reveal a 23 percent rise in total towing-related incidents, driven primarily by a maintenance crisis affecting utility and commercial trailers. While traffic collisions involving towed vehicles decreased by 17 percent, mechanical breakdowns now constitute 77 percent of all towing-related incidents, highlighting vehicle and trailer condition as the sector's foremost challenge.

The data coincides with SMMT Motorparc 2025 figures showing Britain's vehicle fleet at its oldest recorded level, with average car age reaching 9.7 years. The summer harvest season has also arrived, bringing agricultural trailers back to roads after months of disuse. NFU Mutual research indicates collisions involving agricultural vehicles are 56 percent more likely between May and September, reinforcing the need for pre-journey roadworthiness checks.

Utility and agricultural trailers now account for nearly half of all towing-related callouts, surpassing 3,000 incidents in 2025. Regionally, the North West has overtaken the South East as the most incident-prone area, with trailer failures surging 60 percent since 2022, while the North East recorded a 55 percent increase. A growing divide exists between leisure and commercial towing sectors.

Leisure sector improvements, including fewer horsebox incidents and regional caravan reductions, suggest awareness campaigns are yielding positive results. However, utility trailer failures continue climbing, indicating maintenance standards across commercial and domestic sectors require greater attention. Regular servicing, correct loading and proper coupling remain essential to prevent avoidable incidents.

For working trailers, summer represents peak operational period, with agricultural and utility trailers seeing intensive use while rural roads become busier with tourists and cyclists. The Alliance emphasises that trailers stored for extended periods require thorough inspections before returning to service.

The UKTSA urges all towers to perform three essential checks covering tyres, load and connection before every journey. Tyres must be inspected for pressure, tread and deterioration; loads correctly distributed and couplings and electrical connections verified. The Alliance will place ‘The Working Trailer’ at the centre of safety campaigns, collaborating with industry partners to boost maintenance awareness and reduce preventable breakdowns across the Strategic Road Network.

A spokesperson for the UK Towing Safety Alliance said, “It’s encouraging to see fewer collisions involving towing vehicles, which suggests that drivers are becoming more aware of safe towing practices. However, that progress is being undermined by a growing number of preventable mechanical failures. The challenge is no longer simply about how people tow – it’s increasingly about what they’re towing and the condition it’s in. As both tow vehicles and trailers get older, regular maintenance has never been more important.”

Stuart Lovatt, Chair of TyreSafe, said, “Harvest season places extra demands on both vehicles and trailers, particularly those that may only be used for a few months each year. One of the most common issues we see is tyres that appear to have plenty of tread but have deteriorated through age, weathering or prolonged storage. Whether you’re towing a livestock trailer, plant trailer, horsebox or caravan, tyres should always be inspected for correct pressure, damage, cracking and signs of ageing before every journey. A few minutes spent carrying out these checks can prevent breakdowns and significantly improve safety for everyone using our roads.”

Sarah Smithurst MBE, COO, National Trailer & Towing Association (NTTA), said, “Across the NTTA network, we’re seeing a noticeable increase in enquiries from people looking to refurbish older trailers or source second-hand trailers, including imported models, as a more affordable alternative to buying new. While extending the life of a trailer is often entirely appropriate, it’s essential that owners understand that trailers are not maintenance-free. Many have been in service for years, sometimes decades, and components naturally deteriorate over time, even if the trailer has seen relatively little use. Every trailer should be thoroughly inspected before it returns to the road, with particular attention paid to tyres, brakes, bearings, couplings and lighting. Investing in regular servicing and maintenance is far less costly than experiencing a breakdown – or worse, being involved in an incident. The NTTA continues to help and advice new and old trailer users about safety and many are asking for help when towing, especially the reversing aspect of a trailer, now the B&E test was withdrawn. We are also seeing more trailers being repatriated from North America and Europe rather than purchasing new in the UK.”

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