How to redirect the path for ConTeXt in MacVim?

I put this in .vimrc:

map <C-h> <Esc> :w <CR> :!context % <CR>

and $PATH directs "context" to the right place:

/Users/kitz/lmtx/tex/texmf-osx-64/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/Library/TeX/texbin

To open the .pdf:

:!open -a <your choice of viewer here, e.g. skim> %r.pdf