When I was 6 or 7, my grandparents built an addition to their house with their first toilet and shower. (I'm not THAT old... this was less than 50 years ago...) We had to endure the spiders, hornets, cold, heat, darkness and stench of the outhouse on every visit when I was a wee kid. If you were particularly lucky, the poopin' flashlight had not been left somewhere else, and had good batteries...
They weren't complete luddites about the benefits of indoor plumbing, but they found the whole alien concept of pooping inside the house to be deeply, deeply disturbing.
So they installed a powerful ventilation fan intended for a large workshop, or maybe a grain bin, on the wall just above the toilet. We had strict instructions for its use before, during, and after the excretory act so as to ensure no evil vapors could ever escape to befoul the rest of the house. It would just about peel your scalp off, and made the door creak under the strain of the airflow.
My apologies that I have no solution for the OP, only a story...
