helmets are one of them things, its best to try on and see what fits you best, stick to DOT approved helmets
as for dust filters, well yes and NO, some of the full faced helmets have some screening that can help divert some of the dust, but they actually sell things that work BETTER for this
do a search for dust masks and your sure to find many for ATV/MX riding!
a full face helmet gets more protection to you in ANY crash than an open faced one ever will
open face gives you better field of vision and are normally lighter, and honestly, there he one's MOST guys wear when they JUST want to be legal, and not focused on the safety of a full faced helmet(IMO)
been riding MX bikes for 30+ yrs now and seen far too many crashes with both types of helmets and even those NOT wearing any at all to see the advantage of a full face one over the others
the material of the helmet and its features will determine the weight and comfort here too
washable, removable liners are NICE
you's being in a UTV with seat belts and a roll cage(I gather), about any helmet will be OK for you's as the UTV itself has safety features to help save you
keeping dust out?? well, that will be the same on either helmet type if you ask me, its a NON avoidable thin g when you ride and its dry ground your on
best advice, is stay up front of other LOL
let others get farther ahead of you so it can settle more
or buy some actual dust masks made to keep dust out of your lungs
BUT good googles to keep it out of your eye's too, BIG advantage here with them, can be had with colored len's to help on sun, or snow or??
I wouldn;t ride without eye protection personally, just as important as a helmet IMO!
have a look here too on dust masks?
http://www.hondaatvforums.net/forums/wolfsnout/44122-reviews-wolfsnout-offroad-dust-mask.html
also, best place to BUY helmets IMO< is on MX based sites, and look at close outs or discontinued models
they make them by YR to YR on graphic's and last yrs models will be many time HALF price due to NEW yrs graphic's came out, same safety and helmet, just half price due to older decal designs??
you will be limited to sizes and colors, but you can find super deals on helmets on many sites like
Chaperal's, Rocky MY ATv/MX, motorcycle super store , Shadetree, and such sites , and ALWAYS E bay too
but of you have a local dealer near by, go look what they have and try some on, NOT all helmets are sized the same
many run SMALLER than others
you can also try your UTV"S or other OEM"S too, as they too tend to blow out last yrs model helmets too