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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TyreSafe, UK’s charity dedicated to raising tyre safety awareness, has launched a new seasonal campaign warning British drivers that spring rainfall poses a hidden danger often overlooked after the harsh winter months. The initiative, named ‘Drip Drip Drop – ‘Little’ April Showers’, focuses on the rising threat of aquaplaning as more vehicles return to roads that remain treacherously slick from sudden downpours.

National data shows that poor tyre maintenance is a leading cause of fatal incidents, with three quarters of car tyre defects linked to neglect. Research further reveals that at 70 miles per hour (approximately 112 kmph), worn tyres add 27 metres to the standard wet stopping distance, an increase of nearly 30 percent compared to the Highway Code baseline.

Incorrect tyre pressure compounds the problem significantly. Underinflated tyres struggle to channel water away, overheat more quickly and extend braking distances, while overinflated tyres reduce the tyre’s contact patch and compromise grip. Spring’s fluctuating morning and evening temperatures make pressure changes especially common during April.

Even tyres above the legal minimum tread depth can fail in heavy rain. Continental Tyres’ research found that at 50 miles per hour, tyres with 1.6 mm of tread required 6.9 metres longer to stop than new tyres with 8 mm tread, whereas those with 3 mm added 2.7 metres. Light rain after dry spells mixes with oil and debris, creating conditions where worn or incorrectly inflated tyres lose all steering and braking control.

With bank holidays, leisure travel and outdoor activities increasing during longer daylight hours, TyreSafe urges motorists not to assume the worst weather has passed. April showers arrive without warning, and the combination of winter road grime and sudden rainfall can turn a routine journey into a dangerous aquaplaning event within seconds. TyreSafe urges road users to embrace the simple ACT protocol: regular checks of air pressure, condition and tread depth.

Stuart Lovatt, Chair of TyreSafe, said, “April showers might sound harmless, but when they hit busy roads and combine with worn or incorrectly inflated tyres, the consequences can be devastating. Aquaplaning can happen in seconds and without warning. The research is clear – poor tyre maintenance dramatically increases stopping distances in wet conditions. That’s why we’re urging road users to ACT: check your Air pressure, inspect the Condition and monitor your Tread. A few minutes of checks could prevent a lifetime of consequences.”

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Mitas has officially entered a three-year agreement with the National Tractor Pullers Association (NTPA), marking a significant commitment to one of North America’s most extreme motorsports. The partnership, set to run from 2026 through 2028, designates Mitas as the Official Agriculture Tire sponsor of the championship and Title Sponsor of the Mitas National Finals Pull-Off.

Tractor pulling represents a severe test of both raw power and engineering precision. Competitors pilot highly modified machines to drag a heavy sled down a dirt track, with resistance increasing incrementally until only the strongest and best-prepared vehicles remain. Success depends entirely on transferring massive horsepower to the ground under extreme conditions, where tire grip and consistency frequently determine the winner. The NTPA season includes over 60 events across United States, running from spring through early fall, with deep roots in the Midwest. As an official partner, Mitas will gain prominent visibility on and off the track while actively supporting the growth of the sport.

Central to this collaboration is the Mitas PowerPull tyre, a product specifically engineered for tractor pulling to convert raw engine output into winning performance. Designed to manage extreme torque and deliver maximum grip, the PowerPull functions as a slick tyre that permits teams to cut custom tread patterns based on track conditions and individual race strategy, providing a measurable competitive advantage.

The season will conclude with the Mitas National Finals Pull-Off, the championship’s premier event where the year’s top competitors vie for national titles. Scheduled for 18 and 19 September 2026, in Urbana, Ohio, the finals serve as the ultimate showcase of performance, innovation and passion. As title sponsor, Mitas deepens its connection to the pulling community by attaching its name to this marquee competition.

Roberta D’Agnano, Global Marketing Director Mitas at Yokohama TWS, said, “The collaboration with NTPA connects Mitas to two worlds where performance truly matters: tough daily work in the field and the most extreme competitive environments. Tractor pulling is the ultimate expression of what farmers face every day – delivering power to the ground, staying consistent under pressure and performing when limits are pushed.

“Performance isn’t just about winning on the track – it’s about delivering results when it counts most, whether in competition or on the farm. In tractor pulling, every component is tested to the extreme, just as it is in real agricultural operations. That’s why we feel a strong connection with this community. The NTPA community embodies passion, resilience and a nonstop drive to push boundaries; values that are core to the Mitas brand. We’re excited to be part of this world, learning from these extreme conditions and turning that knowledge into tyres that perform where it matters most for farmers and pullers alike.”

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Maxxis has officially unveiled the next generation of its widely used MaxxTerra rubber compound, engineered to deliver marked improvements in both durability and traction for performance mountain bike tyres. Responding to rider concerns about rising costs and the desire for longer-lasting equipment, the brand has focused on extending tyre lifespan without compromising the rolling efficiency that its products are known for.

Following extensive laboratory development, Maxxis engineers have achieved a reported 30 percent gain in tread wear and durability compared to the original MaxxTerra, alongside a 15 percent increase in traction. Crucially, these enhancements come without any sacrifice in rolling resistance, ensuring consistent performance from the first ride through many subsequent outings, thereby reducing the frequency of tyre changes and maximising trail time.

The updated compound is being introduced across the full range of Maxxis trail tyres in phases, with the first phase available immediately. The new generation is identifiable by packaging marked with a New MaxxTerra graphic, while the tyre’s tech badge now simply reads MaxxTerra, replacing the previous designation of 3C MaxxTerra.

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Tana is poised to deliver a compelling presence at IFAT 2026, scheduled for 4–7 May, where the central invitation for attendees is to Feel the Energy through live displays of high-performance machinery, recent innovations and advanced digital tools. This year’s exhibition focuses on how intelligent technology and powerful waste processing equipment can work together to achieve both efficiency and operational excellence.

Visitors can experience the TANA Hammerhead, a mobile shredder engineered for demanding waste environments with a focus on maximising uptime and productivity. On the first day of the show, Tana will also unveil an exciting new product, representing a major leap in waste management technology through innovative engineering and practical operational benefits. Live demonstrations of the TANA Shark shredder will take place daily at 10:30, 12:00, 14:30, and 16:00 at the stand of German distributor VENETO Schwenter GmbH (FS.911/1).

Another highlight is the Tana Wingman, a live digital operator assistant that improves visibility, safety and efficiency. It provides real-time machine data and a live hopper camera view on a tablet interface without needing cloud services or internet, keeping all data secure on site. This system enhances situational awareness during loading and feeding, helping operators react quickly to blockages or irregular material flow while reducing the need to leave the operating area.

Tana is also piloting an AI-driven proof of concept called the TanaConnect Smart Assistant, developed with spogen.ai, which enables hands-free, voice-activated interaction for operators and service teams. This assistant offers intuitive, context-aware access to machine information, reducing time spent searching manuals. At Stand 227 in Hall B5, Tana welcomes IFAT attendees to an interactive space where experts are available to discuss how these solutions can improve productivity and workflows, offering a firsthand look at the future of waste management technology.

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