Eat My Dust: Tire Pollution Throttles Environment
More and better public transit would clear road to healthier future
Source: https://ecori.org/eat-my-dust-tire-pollution-throttles-environment/
For two decades researchers struggled to understand why, after significant rains, spawning coho salmon in West Coast waterways in the Puget Sound region were dying. They tested hundreds of chemicals that leach into the watershed, but couldn’t pinpoint the reason.
A 2020 report finally revealed the culprit: N-(1,3-dimethylbutyl)-N’-phenyl-p-phenylenediamine (6PPD), a chemical that is added to tires to prevent cracking and degradation. When 6PPD, which occurs in tire dust, is exposed to ground-level ozone, it mutates into multiple other chemicals, including 6PPD-quinone (6PPD-q.) This compound is toxic to four of 11 tested fish species, including coho salmon.
The chemical has since been found in the urine of children, adults, and pregnant women in South China.
Unsurprisingly, 6PPD continues to be used by major tire manufacturers, and is found on roads and in waterways around the world. Seventy-eight percent of the world’s oceanic microplastics are derived from synthetic tire rubber, according to one estimate.
The Pew Charitable Trusts report noted the flow of plastic into the ocean is projected to nearly triple by 2040. “Without considerable action to address plastic pollution,” 110 pounds of plastic will enter the ocean for every 3 feet of shoreline by that time. Rhode Island has 420 miles of coastline.
A 2021 study found “extremely high levels of microplastics” in the stormwater of the 12 watersheds that surround San Francisco Bay. The authors estimated the annual discharge of microplastics into the bay was some 7 trillion particles, and half of that was suspected tire bits.
A study published in April found tires, at 24%, accounted for the second-most microplastic pollution emitted in China.
In March of last year, the Environmental Protection Agency proposed a rule that would require manufacturers and importers of 6PPD to report lists and copies of unpublished health and safety studies on the both 6PPD and 6PPD-q to the federal agency. EPA planned to finalize the rule by the end of 2024.
Tire wear particles are emitted continually as vehicles travel — some 600 million tons shed annually worldwide. They range in size from visible pieces of rubber or plastic to microparticles. Research has found that a car’s four tires collectively emit more than 1 trillion ultrafine particles, of less than 100 nanometers, per mile driven. About 2 billion tires are manufactured annually.
Besides the climate-changing, health-degrading pollution created by tire dust and internal combustion engines, a billion vehicle tires are tossed away annually worldwide — worn-out rubber buried in landfills, burned, or left to litter the landscape.
The tire industry has created a 32-member consortium to “transparently and collaboratively work with regulators, partners and interested stakeholders to identify a potential alternative to 6PPD that is protective of motorist safety and the environment,” according to the U.S. Tire Manufacturers Association.
The toxicity of 6PPD-q and its source are hardly the only contaminants that shed from tires. Tire rubber contains some 400 chemicals and compounds, many of them carcinogenic. Research is only beginning to show how widespread the problems from tire dust may be.
Tires are made from about 20% natural rubber and 24% synthetic rubber, which requires 5 gallons of petroleum per tire. Hundreds of other ingredients, including steel and heavy metals, such as copper, cadmium, lead, and zinc, make up the rest.
Electric vehicles won’t solve the problem. In fact, tire emissions from EVs are 20% higher than those from fossil fuel-powered vehicles, largely because they weigh more.
One “solution” to the problem, being pushed by the industry, is to unleash different chemicals, such as 7PPD. Come on.
Reducing the amount of rubber on the road would make the most sense. Such a move would reduce both toxic tire dust and greenhouse gas emissions, something politicians like to call a “win-win.”
Instead, we and all the other life we share this world with are routinely subjected to these kinds of villainy: Florida lawmakers, in 2023, passed a bill that allows for roads to be paved with radioactive mining waste that has been linked to cancer.
The legislation added phosphogypsum to the list of “recyclable materials” that can be used in road construction. Phosphogypsum is a byproduct from processing phosphate ore — phosphate rock mining is the fifth-largest mining industry in the United States — to make phosphoric acid that is used in fertilizer. This solid waste product contains radium, which decays to form radon gas. Both radium and radon are radioactive and can cause cancer.
Radon, an odorless and colorless gas, poses significant health risks when present at elevated levels. It’s one of the leading causes of lung cancer in the United States.
Phosphogypsum isn’t allowed to be buried in landfills, meaning the cost to get rid of it is substantially higher. The Environmental Protection Agency classifieds the material as being “radioactive.” Late last year, however, the EPA approved a pilot pavement project by the Mosaic Co., the largest phosphate producer in the United States, in Polk County, Fla.
Tire dust and radon are sure to make a healthy combination.
Funding, supporting, building, and expanding public transit would lessen the amount of roadway rubber and stack wins. As the American Public Transportation Association notes: “Every segment of American society — individuals, families, communities, and businesses — benefits from public transportation.”
The Washington, D.C.-based organization provides metrics that even a climate denier could get behind:
Every $1 invested in public transit generates $5 in economic returns.
Every $1 billion invested in public transit supports and creates some 50,000 jobs.
Every $10 million in capital investment in public transit yields $30 million in increased business sales.
Home values are 24% higher near public transit than in other areas. Hotels in cities with direct rail access to airports raise 11% more revenue per room than hotels in those cities without.
Public transit even provides a high for free-market junkies. An estimated $39 billion of public transit expenditures flow into the private sector. More public transit means more private profit.
Despite the many benefits of public transit on human health, the economy, and the environment, the powers that be, most notably those in Rhode Island, have long failed to take notice.
The Texas A&M Transportation Institute has reported that congestion in the 15 largest U.S. cities costs nearly $7 billion annually. During the past six-plus decades, however, the United States has spent some $10 trillion of taxpayer money on highways and roads — a quarter of that has been spent on public transit.
We’re leaving a lot of money on the table, even as we make ourselves and Mother Nature sick.
Note: Microplastics are ingested by marine mammals and fish, as fragments have been found in gills and stomachs. This ingestion of plastic pollution can cause a range of health impacts, from neurotoxicity to growth retardation and behavioral abnormalities.
Frank Carini can be reached at frank@ecori.org. His opinions don’t reflect those of ecoRI News.
