Does Pluto have an atmosphere? is a simple
question with a not-so-simple answer of:

Yes, and No

the dwarf planet Pluto has a kind of an "on-again-off-
again" atmosphere; a cyclic atmosphere

and this is so because of its atypical orbit

unlike the eight planets which orbit the Sun, Pluto's
orbit is not a near-circular ellipse; rather, it is egg-like
in shape

consequently, Pluto's distance from the Sun varies
widely in the course of its 248 year orbit

at some times it will be 30 AU from the Sun and at
others, 50 AU; with an "AU" being a unit of distance
approximately 93,000,000 miles, the distance of the
Earth from the Sun

at those times when Pluto is closest to the Sun,
the frozen gases on its surface (98% nitrogen, with
traces of methane and carbon monoxide) will under-
go a change

in the video below, this change is described as
follows,

Pluto's pockmarked surface undergoes a transformation as it orbits near the Sun. Under the additional heat, some of the frozen gases evaporate to form a temporary atmosphere.

As Pluto recedes from the Sun, the gases freeze again and fall back down to the surface.



the above is an excerpt from the History Channel's Universe series