well i really hope your not talking about your actual biological human children, if your talking about your plants its really not good, but from what i have seen it isnt really that bad for them either, even though we love mj smoke there are still toxins in there that in theory arent good for your plantsAs the topic says.
why not buy a packet of activated yeast? put some in a plastic 20oz bottle with a nail whole in the lid.
fill half way with WARM water, then add a 1/3 cup of sugar. shake till it bubbles
bam co2 just shake it every other day