al roker will tell us when the skies may clear, but first to emilie ikeda with the very latest. reporter: tonight, cityscapes unrecognizable in much of the country. an eerie glow disguising manhattan. the washington monument practically hidden and a haze over detroit as warnings of worsening air quality blanket newscasts. dry conditions are causing more wildfires to spark around the region. outside right now, a picture that is simply other worldly. my goodness, it s heavy smoke in the sky. reporter: the smoke today clouding skies so much, the faa issued a groundstop temporarily pausing all flights into laguardia and slowing air travel into newark and philadelphia. from the midwest to the northeast and down the east coast, 90 million americans are under air quality alerts from wildfire smoke.e. ththe dangerouous plumes arare funnelining into 16 6 ststates from m fires in canadada. more than 400 are burning. 239 of them remain out of control.