A desert island question, or rather many remote areas, even in the US.
You are on a beach with plastic debris. There is no access to recycling or safe land filling. The alternatives are open burning or ocean dumping, and as a practical matter, it will be left where it is. Do you:
- Throw the plastic on the campfire to prevent micro plastic pollution.
- Burning the plastic more cleanly in a rocket stove or similar.
- Leave it be.
Further, I have studied beach plastic in my area and read studies world-wide. The main culprit of dioxins when plastic is burned IS PVC, and PVC sinks (it is heavier than water). There is NO PVC in beach plastic, only PET and LDPE, which are just carbon, hydrogen, and oxygen. They can smoke if burned with poor air mixing, but there is nothing in their chemistry that is more polluting to burn that wood.
Also, drift wood contains elevated levels of chlorine. Seawater. But 20-40 times less than PVC plastic.
Burning is never great, and even less so when the heat is not used for something necessary. Micro plastics are a problem, but how big a problem is far from established. Maybe very small, maybe a long-term time bomb. We don't know.
I've read that this is also a problem in Nepal. A better stove is needed.
- Trekers bring plastic.
- The locals have no trash disposal methods (they don't have plastic trash--they farm and they keep cattle).
- They need fuel for cooking and heating, and they have little wood. The alternative may be yak dung.
I've been doing some experiments with stoves that can burn beach plastics without smoke, far more cleaning than a typical cooking fire. I could cook a meal with plastic and not get any soot on the pot. But I don't know what I think about that.