PHILADELPHIA (CBS) — April 22 is Earth Day and runners looking for some fresh air celebrated the occasion on MLK Drive in Philadelphia.

The “Run for Clean Air” kicked off Sunday morning for 5k and 10k participants near the Art Museum and continued along the Schuylkill River.

The clean air council has held the run in Philadelphia to celebrate Earth Day since 1981.

The run is one of the region’s longest-running charity races and its largest Earth day event.