You dont understand, its not exactly the smoke that i am looking for protection from, its the ash that kicks up and comes right at your face when you move the wood/coals around inside the fire box. also when auguring out the ashs, there becomes a big ash cloud, sure putting your shirt over your nose and mouth helps mentally, but i do not believe it really does as much as we assume. lastly my boiler has a horizontal flue that needs to be cleaned about once a month. the way you clean it is by removing the back access hole and using a pushing scrapper to push all the ash/soot to the front where it drops back into the fire box. while doing this, there is often times that a big cloud comes rushing back at you.
so as you can see, an owb is much different than a bon fire or grilling out