Last week, Chicago woke up to a hazy orange sky and some of the worst air quality in the world, for one day, even worse than cities known for heavy smog. The smoke came from wildfires burning over a thousand miles away in Canada. This week on Chronversations, host Stella Huang talks to students who were caught off guard, a biologist who explains how it traveled here, and a meteorologist who reveals why it might happen more often than we think — and what you can do about it.