Kamita Gray and her mom have spent a lot of time volunteering at Brandywine Elementary School, helping kindergarteners learn to write their names and making sure everyone has a turkey on Thanksgiving and Christmas. Every time they’re at the Maryland school, they’re struck by the heavy black smoke from diesel trucks roaring by, en route from construction sites or delivering mining waste to dumps.

Get in-depth coverage of current and future trends in technology, and how they are shaping business, entertainment, communications, science, politics, and society.

Advertisement