Custom Biome and Dimension questions

I am working on setting up a new biome and eventually replace the default overworld generation. 
When looking at a tutorial (www.youtube.com/watch?v=epSVtMEYR6c) they showed that you can add ambient sounds, effects, and some other things.
My question is, how do you add multiple particles or ambient sounds to the biome, if you can at all. 
I have this:
"particle": {
    "options": {
        "type": "smoke"
    },
    "probability": 0.1
}

But can I put it into an array instead so I can have multiple?
Like this:
"particle": [
    {
        "options": {
            "type": "smoke"
        },
        "probability": 0.1
    },
    {
        "options": {
            "type": "fire"
        },
        "probability": 0.1
    }
]