Talk about killing two proverbial birds with one stinky, wildlife-poisoning stone …

According to new research from a team at Australia’s Royal Melbourne Institute of Technology University (RMIT), a most ideal way to dispose of discarded cigarette butts — and there are plenty to go around — would be to pave new roads and sidewalks with them.

While butt-infused footpaths and roadways don’t immediately invoke the most pleasant imagery, the benefits would be dramatic. For one, in lieu of going from ashtray to rubbish bin to landfill (or being flicked outdoors before winding up who knows where), the sky-high mountains of non-biodegradable cigarette butts generated each year would be isolated to one specific place and, in turn, help put a dent in a massive waste problem.

Secondly, the RMIT team found that cigarette butt-bolstered asphalt helps to reduce thermal conductivity. That is, roads and sidewalks embedded with butts trap less heat from the sun and could potentially help to reduce the urban heat island effect, a phenomenon that makes cities warmer — often detrimentally so — than rural areas.

Locking in the chemicals

As team lead Dr. Abbas Mohajerani notes, cigarette leftovers wouldn’t simply be mixed into asphalt as is and then applied to infrastructure projects as an aggregate.

"In this research, we encapsulated the cigarette butts with bitumen and paraffin wax to lock in the chemicals and prevent any leaching from the asphalt concrete," explains Mohajerani, a senior lecturer at RMIT’s School of Engineering, in a news release published by the university. "The encapsulated cigarettes butts were mixed with hot asphalt mix for making samples."

Most importantly, Mohajerani and his team concluded that this very special asphalt meets standard traffic requirements.

And this isn’t the first time that Mohajerani has garnered headlines for discovering new and inventive ways to deal with Australia’s Philip Morris-manufactured leftovers. In 2016, he published research suggesting that cigarette butts should be entombed in construction bricks.

This method, in addition to preventing errant butts from marring Australia’s stunning natural landscapes and polluting waterways, was found to improve the insulating quality of bricks, which, of course, can lead to slashed heating and cooling costs. What’s more, Mohajerani and his colleagues found that butt-based clay bricks required significantly less energy to fire than clay bricks lacking this unlikely additive. The more butts the better, in fact.

"Cigarette filters are designed to trap hundreds of toxic chemicals and the only ways to control these chemicals are either by effective encapsulation for the production of new lightweight aggregates or by incorporation in fired clay bricks," says Mohajerani.

Cigarette butt on beach A cigarette butt litters a beach in New South Wales, Australia. (Photo: May/flickr)

Next step: Butt wrangling

While Mohajerani’s findings are intriguing, a not-so-small question remains unanswered: How does one go about collecting enough cigarette butts — one of the most, if not the most, pervasive forms of litter in the world — to build city-cooling roads and ultra-insulating brick homes?

Mohajerani’s latest research, published in the journal Construction and Building Materials, doesn’t appear to offer any suggestions. (To be fair, delving into the "physico-mechanical properties of asphalt incorporated with encapsulated cigarette butts" seems an admirable enough endeavor without figuring how to acquire said cigarette butts.)

Enviro pole cigarette butt recycling, MelbourneLucky for Australian city planners, if Mohajerani’s vision for cigarette waste-studded asphalt was to ever be realized in a real-world scenario, they wouldn't need to look too far for inspiration.

Melbourne, recently heralded as the world's most livable city in the world for the seventh year in the row, is home to a successful butt-recycling scheme in which over 350 cigarette waste disposal points — or "Enviropoles" — have been installed around town. The Enviropoles are regularly emptied and their contents shipped off to the United States where Trenton, New Jersey-based TerraCycle recycles the plastic-containing cigarette filters into a variety of consumer products like outdoor plastic furniture and shipping pallets. While TerraCycle expanded its lauded Cigarette Waste Recycling Program into Australia in 2014, Melbourne is only one of two councils with a citywide collection scheme.

Earlier this year, Lord Mayor Robert Doyle told Waste Management Review that upwards of 200,000 butts are retrieved each week from the city's network of Enviropoles.

Of course, this isn’t to say that Melbourne should end its partnership with TerraCycle, a lauded company that’s grown from a scrappy early-aughts start-up hawking worm poop-based liquid fertilizer packaged in reclaimed soda bottles to a global powerhouse specializing in finding creative new uses for difficult-to-recycle waste items. Yet if cigarette butt-embedded roads and sidewalks do ever become reality and raw materials are needed, TerraCycle might have some healthy competition Down Under.

But then again, more is certainly merrier when combating Australia's most frequently littered item: cigarette butts.

While smoking is on the decline in Australia, particularly among young people, there’s still more than enough discarded Winfield and Longbeach butts to go around. Mohajerani notes that 25 to 30 billion filtered cigarettes are smoked in Oz each year. An estimated 7 billion of them are littered — chucked into the street, snubbed into city sidewalks or rudely discarded in the great outdoors.

While this seems like a lot, Australia appears relatively far down the list — number 64 — when ranking countries by per capita cigarette consumption. Montenegro, Belarus, Lebanon, Macedonia and Russia top the list while the U.S. comes in ahead of Australia at 57.

Inset photo: Ben Tsai/flickr

Matt Hickman ( @mattyhick ) writes about design, architecture and the intersection between the natural world and the built environment.

Why we should pave roads with cigarette butts
Scientists at RMIT University in Melbourne, Australia, want to put errant butts to an intriguing new use.