In January, Margarita García stood over a hot griddle, roasting cocoa beans to make a fine chocolate.
Outside, the Oaxacan air was cold. But inside, the comales where the beans were cooking warmed the tiny brick-and-mortar room that houses the Lanní chocolate factory.
García removed the wood from the comales, since only coals are needed to roast the beans, releasing swaths of smoke into the air, which filtered out the open windows and into the downtown square.
University of Texas engineering students were visiting the southwest Mexican town as part of a study abroad experience, organized by International Engineering Education and the nonprofit “Tejiendo Alianzas,” to meet and learn about underserved communities. They crowded around García, watching as she moved the cooked beans from the griddle to a table to grind them, then roll them into bon bons.
In a corner of the room, a device created by UT engineers, known as a smart home beacon, measured the particulate matter in the air — in this case, the thick gray smoke. It picked up spikes in the particles.
