The researchers looked at how different materials used in building roads impact the environment in various ways, not just through carbon emissions. They studied 13 main construction materials like cement, steel, and asphalt to see how much they contribute to things like pollution and global warming during their production. They found that these materials have a big impact on the environment, with a few key pollutants being responsible for most of the harm. By figuring out which materials cause the most damage, we can better understand how road construction affects the environment and work towards making it more sustainable.