If this were possible, the smoke from burning animal and plant tissues would contain all manner of proteins from that organism. This would mean you could have prions spread via smoke as well, but there's never been any evidence of such a thing. As @Cure said, heat denatures proteins and in order for smoke to contain these proteins, it would have to be liberated by the burning process, which would denature the proteins. Also, just how much of the spike protein do you think exists in the tissues anyway? If it's constantly shedding, which would mean all proteins shed but that's never been observed at all, then how much is there in spike protein volume anyway? All these theories always seem to hinge on there being a huge and infinitely resupplied volume of spike protein over long periods of time. That doesn't sound plausible at all and there would be evidence of it in easily noticeable routine tissue/blood analysis. I've yet to see honest and demonstrable proof of that from non-amateur sources.