ALTADENA (CBSLA) — A large jetliner spotted flying low over the foothills Monday belonged to NASA and was part of a study on air quality, officials said.

The large DC-8, painted white with a blue stripe and the NASA logo on the tail, was spotted flying over Altadena at the height of afternoon rush hour in the San Gabriel Valley, according to the Los Angeles County Sheriff’s Department.

Low flying plane over Altadena and Southern California today. It just passed along the foothills a few minutes ago. We have been told the plane belongs to NASA. Plane is a DC-8 with a call sign of NASA817#LASD #altadena #NASA pic.twitter.com/CBqDR4WW7T — Deputy Dan Paige (@LasdDan) July 23, 2019

The plane evidently took off out of Palmdale and flew a 2,359-mile meandering path into Central California and across Nevada. It landed in Boise, Idaho at about 7 p.m. local time.

NASA spokeswoman Kate Squires told CBSLA the aircraft was headed to a NASA/NOAA partnership mission dubbed “FIREX-AQ” to study the effects of fire smoke on air quality.

“Since the plane was fully loaded with a suite of science instruments that are able to study different aspects of air quality, the CA Air Resources took advantage of the opportunity to have the science team observe the LA Basin and Central Valley as the plane made its way out of the state and on to Boise,” Squires said in a statement.

CBSLA’s Jasmine Viel was one of the commuters who saw the plane flying by.

“It was scary, a little bit. You didn’t know if was going to land,” she said. “Everyone kind of stopped in their cars, looking up. It was big and loud.”