I had an experience that has made me sensitive to burning smells as well. When I was about 13, there was an extension cord that was running under my bed that shorted out while I was asleep. I woke up to a burning, copper odor (like a hand full of pennies). I got up to check it out but the light wouldn't turn on in my room. My dad reset the tripped breaker and I saw sparks spew out from under the bed, bouncing off the blanket that had been covering me just a minute before. I'm certain that the circuit breaker saved me. The odor plus the sight of those sparks left a huge impression on me.

Decades later, I'm still hyper-sensitive to burning odors.

As I reflect on it, I'm not big on extension cords, either.