When given a choice—paper or plastic, cloth diapers or disposables, garbage can or recycling bin—most of us do what we think is greenest. The problem is, we’re often wrong.

“We make emotional decisions, but often there’s no scientific proof to back things up,” says Arpad Horvath, professor of civil and environmental engineering. For several years Horvath has focused on developing systematic methods to assess the environmental impact of our industrial processes, consumer goods and services and beyond.

“When people want to do the right thing for the environment, we should be able to give them the correct information to make informed choices,” he says.

With his team in the Consortium on Green Design and Manufacturing, Horvath analyzes every environmentally significant process surrounding a product or service. They measure each drop of energy consumed, every raw material processed and any terrestrial or marine ecosystem impacted by the manufacture and use of that product, even unto death (when, ideally, it is reborn through reuse or recycling).

In a 2004 study, for example, Horvath’s assessment revealed that reading the New York Times wirelessly on a PDA instead of having the paper delivered to your door requires consumption of about 140 times less carbon dioxide and 26 to 67 times less water. Now he is bringing his research to bear on the building industry, examining a building’s sustainability in the context of the entire supply chain behind its construction, operation, maintenance and end of life.

“Besides transportation and electricity generation, buildings are the single greatest consumers of energy and other resources,” he says. “And nearly every sector of our economy—mining, manufacturing and services—supplies to the building industry.”

To tease out these myriad factors, Horvath is using techniques like economic input–output analysis, a model traditionally used to forecast changes in the economy. This approach maps quite well to the supply chain, Horvath explains, helping identify the number of suppliers, their contributions to a particular product or service and the environmental impact of each link in the chain.

The energy that goes into a building’s construction and use is only part of the story. Builders must consider health hazards such as fine dust blowing from the construction site or operational issues like maintenance, cleaning and renovations, to name just a few.

“We’re also looking at the end of a building’s life,” he adds. “Demolishing it and hauling the debris to the landfill seems wasteful. Can we do better?”

But Horvath is a researcher, not a builder. His mission is to collect the data and spread awareness that the environmental footprint of the things we make and the services we use goes far beyond our immediate field of view. Horvath also spearheaded and is directing a new training program, the Engineering and Business for Sustainability Certificate Program, launching this year, to educate young engineers about the importance of environmental impacts and other sustainable engineering practices.

“All we can hope is that, once we can provide the data, people will make their own informed decisions,” Horvath says. “You can’t argue with the numbers.”