The particle commands "dust" and "falling_dust" doesn't work but they are in the command index.

The dust command:

/particle minecraft:dust ~ ~ ~

The Output:

Expected double at position 25: ...rat:dust <--[HERE]

and the other command:

The falling_dust command:

/particle minecraft:falling_dust ~ ~ ~

The Output:

Expected double at position 33: ...rat:dust <--[HERE]

Here are some Pictures: