The pull of the foul air to Northern California was significant enough that the Bay Area Air District issued an air quality advisory. According to AirNow, a federal air-quality measuring app that measures air quality in real time, the air quality at 8:30 a.m. through much of the region was only moderately healthy.

Smoke from wildfires in Canada is making it harder to breathe in Ohio and several other states. Here's how long it will last and what else we know.

As hundreds of wildfires continue to burn in Canada, the smoke from the flames is bringing potentially dangerous air quality to parts of the United States.