Researchers Testing Air-cleaning Technology, Carbon Storage

A company in California is working with another in Canada to collect carbon dioxide (C02) and put it into new concrete. Carbon dioxide is a major polluter. The waste gas traps heat in the atmosphere, creating what is called the greenhouse effect.

The companies are Heirloom Carbon Technologies based in San Francisco and CarbonCure Technologies of Halifax, Nova Scotia. They work on carbon dioxide capture systems. Their work supports the results of a study from the United Nations. It found that removing carbon dioxide from the air is as important to climate health as reducing the production of the gas.

Some companies have systems that can remove carbon dioxide from the air. But then, the question is, where do you put it?

Heirloom recently collected 30 kilograms of carbon dioxide gas from the air and transported it to Central Concrete. Central Concrete was able to put the gas into a new kind of concrete. The joint effort between Heirloom and CarbonCure was the first time that carbon dioxide taken from the atmosphere using such Direct Air Capture (DAC) technology had been secured in concrete, several scientists said. The waste gas will stay there for hundreds of years, they added.

The amount of carbon dioxide the partners captured amounted to about as much as a car would produce in about 120 kilometers of operation.

Julio Friedman is the top scientist at a company called Carbon Direct. It helps businesses reduce the amount of carbon dioxide they produce.

He noted that the amount of CO2 contained in the project is extremely small compared to the overall amount that needs to removed. But, "that's how it starts," he said.

Shashank Samala is Heirloom's chief. He explained the process, which involves limestone. "Limestone has this natural ability to pull carbon out of the atmosphere," he said, adding "what we do here is just give it more superpowers."

Heirloom heats crushed limestone, which releases the carbon dioxide it contains. Then the limestone can capture more gas in the same way a sponge takes in water. The company then repeats the process multiple times to collect more of the polluting gas.

CarbonCure mixes the gas with concrete's ingredients, which makes a stronger final product. The concrete does not even require cement, a usual additive to concrete. This helps also in the fight against carbon dioxide as cement production requires a lot of energy.

CarbonCure also adds the gas to water that had been used to wash out concrete trucks. That water then helps create more concrete.

The technology is promising but would require widespread use to to make a real difference in pollution levels. Samala guessed it would cost hundreds of millions or billions of dollars to establish enough centers and systems.

He said he thinks companies that work in other pollution-reducing areas will support carbon capture projects like his.

Building is a very polluting industry. Concrete alone accounts for eight percent of the world's carbon dioxide production. The leader of CarbonCure said the new processes would reduce concrete's carbon production by about five percent.

Anu Khan is a science director at Carbon180, a group that works to reduce carbon pollution. He called the technology "a really thoughtful way to get around the current bottleneck of storage" for captured carbon.

I'm Dan Friedell.

Dan Friedell adapted this story for VOA Learning English based on a report by Reuters.

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superpower –n. usually a fictional person who has special abilities that humans do not have, like superman

sponge –n. a piece of light natural or artificial material that becomes soft when it is wet, is able to take in and hold liquid, and is used for washing or cleaning

bottleneck –n. something that slows down a process