Since it is more airborne before it settles I
doubt you can prevent exposure by spreading
something on your lawn. Buff up your immune
system and when you see chemtrails try to stay
inside. Hard to imagine one can totally avoid
exposure at this point. Hopefully as awareness
of the health issues which are caused by the
exposure grows, there will be an antidote or
some other way to ameliorate the symptoms and
health issues which present themselves.
Also arming yourself with information will aid
in your quest for an effective aid to keeping
your immune system amped. I am using Essiac.