Difficulties with PS1.

[Dmitry <lbvf50.mobile@gmail.com>]

Greetings!

Why variable PS1 dose not change when set it before a command:
Like this:
A="a1" LANG="C.UTF-8" PS1="new" B="b2" bash --noprofile

$A, $B, $LANG -changed, $PS1 - not.

Works only when I explicitly set in current process.

export PS1="(chroot) $PS1"

Is not this syntax:
VAR="..." VAR1="..." command

Set an environment variables?

Thank you!