Algae Cuts Asphalt Health Risks by 100-Fold

That smell you notice on hot summer days when walking past fresh pavement? It turns out those fumes contain harmful chemicals like benzene that can affect our health.

But engineers have found an unexpected solution hiding in wastewater treatment facilities. Algae, when applied as a thin coating to roads, can reduce asphalt's health impact by 100 times.

Elham Fini, a professor at Arizona State University, led research showing that asphalt releases millions of molecules when heated. Some are harmless, but others have been linked to neurological problems and respiratory issues.

Here's what makes asphalt tricky. It's basically the leftover material from refining crude oil into gasoline and jet fuel. This black, glue-like substance binds rocks and minerals together to create roads, parking lots, and roofs across the country.

When temperatures rise, certain molecules escape into the air. These include benzene and other aromatic compounds that create that distinctive asphalt smell.

The Bright Side

The algae solution offers multiple wins. Treatment facilities can grow algae while cleaning wastewater, removing excess nutrients in the process. Then engineers harvest that algae and convert it into a special coating for roads.

The algae's natural chemistry targets specific harmful molecules. While it only reduces total emissions by 30 to 40 percent, it specifically captures the most dangerous compounds. That selective targeting creates the hundredfold reduction in health impact.

Application is surprisingly simple. Road crews mix the algae-based material with granules and apply it to the top inch or two of new pavement. The coating stays near the surface where it works best, rather than getting buried deep in the road.

Fini and her team are now working with industry partners on demonstration projects. They're fine-tuning the application process to make it easy for existing paving operations to adopt.

The research covers multiple health concerns. Published studies already show reduced neurological impacts, and current work focuses on acute respiratory effects.

This innovation addresses a problem most people didn't know existed, using a resource that treatment plants produce naturally while cleaning water.