What are "Code Purple" air quality alerts? The Air Quality Index has six color-coded categories, ranging from cleanest to ...

Air quality alerts can change quickly during wildfire smoke events. Here’s what Code Orange and Code Red mean, who is most at ...

When an air quality alert is announced, here are what the code colors mean and what the health dangers are as Canadian wildfire reaches Delaware.

Wildfire smoke from Canada and Minnesota has led to a Code Purple alert for Pennsylvania on July 17. See the air quality map.