Timelapse satellite imagery released by the Cooperative Institute for Research in the Atmosphere (CIRA) shows the movement of the Canadian wildfire smoke over the northeastern United States from Saturday, June 3 to Thursday, June 8.

The smoke caused air quality to plummet across the region, including in the New York City metropolitan area where flights were delayed, festivals were canceled, and sporting events postponed over poor visibility and health concerns.

By Friday, air quality had improved in New York City, according to the US Air Quality Index.

However, dozens of air quality alerts remained active in other states. On Friday, as the smoke drifted south, the air quality in parts of the Northeast, Mid-Atlantic, Ohio Valley, and Midwest was at “moderate to unhealthy” levels, the National Weather Service warned. Credit: CIRA via Storyful