An interesting argument against explaining your reportage and using first person in nonfiction narrative from Roy Peter Clark at Poynter.
"When we read a novel, watch a movie, see a play, if things go well, we don’t just watch an imitation of life — we enter into it. The author, like the magician, has created an illusion. The lights dim, the curtain opens, images flash on the screen and we are transported, most often to another place and another time.
"By now, most of us understand the engineering of this effect. It comes from scenic construction, from character details, from dialogue, from the variation of points of view, from time in motion, all the strategies of fiction that Tom Wolfe argued could be borrowed by the responsible reporter."
Also, note that Tom French makes an argument that nonfiction narrative is harder to write than fiction. What do you think?