I was thinking about homeless people on the bus. It is
possible one of the objections to the homeless is the smell.
What would improve things is a simple technology to end
body odor. Perhaps a body surface probiotic could replace
the usual skin flora with a new scentless version.
One possibility
is the natural flora of the skin of children. I
am under the impression that children do not have body
odor. They do however have a coating of bacteria known
to succeed on the surface of the human body.
So, make versions of those bacteria that are immune to a
specific antibiotic, then make an antibiotic rinse loaded
with scentless probiotics. This replaces the old bacteria
with the new ones.
Further improving this would be engineering the bacteria
to metabolize body odor chemicals, possibly among them
butyric acid. That way the new bacterial coating would
metabolize things the body itself produces.