Nope. Gas torii are real things (there's one around Jupiter created by Io, and Enceladus produces one around Saturn), but they are wispy things. They are the result of gas being ejected or stripped from an orbiting body, so right away we can say that no such thing could exist around an Earth with no moon, because you need the moon to create the ring! Stripping gas from a moon produces such a ring because the individual gas particles remain in orbit around the primary, pretty close to the orbit they started in--that being the orbit of the moon itself!--with the relatively minor perturbations caused by whatever stripped them from the moon causing them to spread out into a torus.
There is, however, no restoring force holding those particles together as a coherent ring against internal pressure. They persist only due to a combination of being so thin that any individual gas particle is highly likely to complete a whole orbit without actually bumping into any other gas particle, and being continually replenished by the source moon. If a ring were thick enough to have noticeable pressure in the middle, it would simply blow itself apart.
Note that Niven's Smoke Ring is fed by the continual loss of gas from Goldblatt's World, which is stripped off by Voy's (the neutron star's) tides. It takes a huge continuous input of new gas to maintain it. Even so, the Smoke Ring is not particularly plausible itself. Niven gets away with it because the story is good, the Rule of Cool is in operation, and the environment is exotic enough that the average reader can't immediately recognize it as implausible. After all, who knows what can happen in the extreme environment around a neutron star stripping gas from a close gas giant? In reality, what should happen is that you get a hot, violent accretion disk, which spirals inwards due to loss of energy to internal friction from tidal shear--not a cozy, habitable Smoke Ring at all! Try to put it around an Earthlike planet instead, and familiarity kills your suspension of disbelief.
You could, however, go with an artificial gas torus, held in by a thin, solid, artificial membrane, with active stationkeeping. That's the approach taken by the Orion's Arm worldbuilding project, for example.