Floodlights at the Providence Park show the fog around the ground
Players took breaks every 15 minutes and oxygen tanks were made available because of poor air quality during a National Women's Soccer League match.
Portland Thorns played Sky Blues FC after days of hazy skies caused by wildfire smoke in Oregon.
Although air quality tests taken six hours before kick-off measured outside the healthy range, the game went ahead.
A crowd of 17,986 saw Portland qualify for the play offs with a 2-1 victory at Providence Park.
Source: bbc.com