Smoke grenade

Smoke grenades are common device employed by the Equalists. They are re-occurringly used because they help tip the balance between bender and non-bender. These smoke grenades quickly release a massive amount of green smoke. They are more of a choking-gas and do not harm people. All breathers of these gasses have not expressed any occurring side-effects. They appear to affect neither the Equalists who wear their masks, or Naga, or Pabu as seen in The Revelation.

History
The smoke grenades are commonly used by the Equalists. They are first seen in action when Korra and Mako try to find Bolin at the Triple Threat Triad's hideout. Instead they find the Equalists, and when they attempt to pursue them, the Equalists flee and deploy a smoke grenade which buys them more time.

Soon after, Korra and Mako fight two Equalists head on. The chi blockers prevail and are approaching the two immobile benders when Naga escapes her ropes and attack. The non-benders retreat by throwing their smoke grenades at them and take off on their motorcycles.

Since then, Tarrlok leads a task force into an underground base where chi-blockers hone their skills. One chi-blocker lets loose a smoke grenade, but Korra uses water to freeze it before it detonates and consecutively pursues the fleeing equalist.

Weaknesses
The smoke grenades only buy some time, they don't render people useless nor do they slow the people targeted by a huge amount of time. However, when a few seconds are needed, the smoke grenades are effectively the perfect device.

A quick waterbender armed with water can quickly freeze the smoke grenades negating them, as shown by Avatar Korra. Although air benders aren't common, it seems one could easily blow the smoke away making it useless.