NEW: Code Red air quality alert issued for Thursday

Haze from Canadian wildfires earlier this month as seen over DCA (staff photo by Jay Westcott)
The concentration of Canadian wildfire smoke in Arlington and the D.C. area is expected to get worse tomorrow.
A Code Red air quality alert has been issued for the region on Thursday. That means that those with certain health issues should avoid outdoor activities and even healthy individuals should limit their time outside.
It comes after a hazy day today, with air quality readings in the lower Code O