Air Filters: A Guide to Smart—and Not So Smart—Models as Covid-19 and Wildfires Drive Demand – The Wall Street Journal

“Eek, Nicole. Time to close the windows!” shrieked Mila.

OK, fine, Mila didn’t shriek. It didn’t say anything at all. Mila is a portly, Wi-Fi-enabled smart air filter sitting in the corner of my bedroom. She—er, it—sent the exclamation as a push notification to my phone and explained more in its app: “The AQI is rising and I can’t keep up.”