This DIY box helps clear indoor air of the coronavirus. Why aren’t more people using them?

When cholera ravaged Europe and North America in the 19th century, people “revolutionized sewage” by creating the modern sewage system, said Andrew Noymer, an associate professor of population health and disease prevention at UC Irvine. “They could have just said, ‘Boil your water.’ But they didn’t do that. They gave people clean drinking water.” Ensuring clean air indoors is “the 21st century equivalent,” Noymer said. But “it’s a long-term solution, and people are still hoping that COVID is just going to go away.”