For days, three US cities have been listed as having the worst air quality in the world. Portland, Seattle, and Denver are among the 10 worst cities for air quality, according to world air quality monitoring agency, IQAir. It’s all due to historic wildfires that continue to burn in parts of California, Oregon, and Washington. Air quality in several other areas out west is listed as “hazardous” or “very unhealthy,” and has been for days, per data from government-managed air quality organization AirNow. If you live in one of these areas, but you’re not under immediate threat of wildfire reaching your home, it’s only natural to wonder what this means for your day-to-day life, including your workout routine. And, even if you don’t live in one of those areas, you may still live somewhere that experiences poor air quality from time to time. To read the full story.