The growing negative impact of microplastics on our environment has started to receive extensive attention by scientists. The environmental editors at The Guardian recently analyzed several studies and concluded that microplastic pollution is now “spiraling out of control.”

Researchers are now referring to the extensive use of plastics as a “global plastic cycle” equivalent to the well-documented “carbon cycle” – both of which are directly related to the built environment we humans have developed. Because people literally breathe, eat and drink microplastics, their rising levels are not surprising, and are nothing short of alarming given their associated health and ecological risks.

Social concerns about how to better manage plastic consumption have become almost as universal as concerns over carbon reduction management. For example, plastic straws have become a target on the radar of many consumer organizations and consumers themselves. But are straws really the biggest problem?

What many may not realize is that as much as 85 percent1 of the microplastics that end up in our environment come from roads. The culprit is cars; both tire and brake-pad wear are the significant contributors.

Scientists have even come up with a name for roadway microplastic accumulations: “road-associated microplastic particles” aka RAMPs. Tire-wear particles are considered the leading source.

Testing Underway

Several years ago, Pavement Technology, Inc. along with the Texas A&M Transportation Institute (TTI), embarked on the development of a novel technology to sustainably introduce photocatalytic-grade titanium dioxide (TiO2) to pavements by combining titanium with the company’s long-proven, pavement-penetrating preservation technology.

Initial results have been beyond earliest forecasts. In the field, roads retrofit with photocatalytic penetrants are showing as much as 50 percent vehicular NOx removal, while more than tripling solar reflectance index (SRI) values, thereby mitigating Urban Heat Island effect (UHI).

The Texas A&M Transportation Institute is currently conducting extensive tests on the microplastics decomposition efficiency of TiO2. In other independent studies, photocatalytic-grade titanium has proven to remove 98 percent of plastics2, including but not limited to the various forms of microplastics found in RAMPs.

Details of TTI’s latest research should be available soon. For now, it is becoming increasingly likely that the strong photo-reactive nature of titanium will provide another strong environmental benefit at road-level by naturally reducing microplastic accumulations from tire wear.

Conclusion

Plastics have half-lives in the hundreds of years. If left “’spiraling around the globe” atmospheric RAMPs will remain free to invade our air, contributing to the hazards related to a global plastic cycle. Scientists have sounded the alarm. The transportation industry is listening.

  1. Carrington, “Airborne Plastic Pollution ‘Spiraling Around the Globe,” The Guardian, April 12, 2020
  2. Nabi I and Bacha A, et al., “Complete Photocatalytic Mineralization of Microplastic on TiO2 Nanoparticle Film,” iScience, July 24, 2020