I would replace the cabin air filter, preferably one with activated carbon to absorb odors from the outside. I had a very bad smell coming from the vents of my 2013 Equinox. It turned out mice had made a nest on top of the cabin filter. I replaced the filter and sanitized the vents and haven’t had any problems since.
More importantly, the 2.4l 4 cyl engine in 2010 to 2013 Equinox model had a problem with high oil consumption due to premature wear of the piston rings. Please check the oil level on a regular basis.
My Equinox started using oil at 20 to 25k miles. The pistons, rings, and timing chains were replaced at 42k miles under warranty. The powertrain warranty is 5yrs/100k miles, I don’t recall if there is an extended warranty or recall for this issue. I started this thread when I discovered my Equinox was using oil. It’s long, but has some good info.
Good luck with your Equinox.
Ed B.