For my first round of tests I printed two copies of my test chart and two copies of the Photodisc target (on one sheet of paper). One copy of each went into a sealed zip lock bag, in a closet which remains closed most of the time. The other three copies were tested as follows:
Ozone Test: I have a whole house electronic air filter installed in the return to my air conditioning system. This filter is a known ozone source. One sample was taped to a piece of matte board, and placed on the bottom of the return duct, approximately 1 foot from the output of the air filter. (Prints on PGPP begin to shift within 48 hours in this "ozone chamber.") Note that this test area is in complete darkness, so UV is not a component of any shift in these tests. On the Epson PGPP, a couple of days in the ozone seems to equal about a month to 6 weeks in my work area. I can't say the same ratio holds true for any other paper, however.
UV Test: A second sample was placed outside a window (between glass and screen) of a window that
faces onto my front porch. In the summer, no direct light reached the samples, but lots of indirect light reflected
from the white walls of the house and porch roof. 
In the fall, as the sun got lower in the sky, the samples started getting a few hours of direct
sunlight each morning. Now that it's winter, I've given up on the outdoor test, for the time being.
I don't think freezing the prints has any meaningful analogue in terms of normal display environments.
Unless you're storing your prints in the freezer!
This is not purely a UV test, and I'm sure there is some ozone in the outdoor air, too.
West Window Test: The final sample of each paper went on display inside a west facing double pane, low E window. The prints were placed between the glass and a roller shade, so I think airflow across the surface of the print was minimal, but the prints were not pressed directly against the glass. Tall trees block the evening sun, so the prints were exposed to direct, filtered sunlight for about 2 hours each day.
For some of my most recent tests, I've made a few changes. I still use the Ozone and the UV tests described above. But instead of the West Window test, I've taken one set of samples to my office. I think this provides more variety in test environments. And for a very few samples, I've created a "pre ozone" chamber. These test environments are:
Office Test: Each sample is placed face up on the windowsill of an East facing Window. The windowsill gets direct sunlight for 4 to 5 hours per day, but that sunlight is filtered through two panes of glass and a dark gray window tint film. There is slight air flow on the prints from a ceiling HVAC vent, and no fluorescent lighting Prints on Epson PGPP show noticeable orange shift in 2 to 3 weeks.
Pre-Ozone Test:These samples are placed in the same air duct as the Ozone Test samples,
but before the air filter. Since the ozone levels should be higher downstream of the
air filter should be higher than those upstream, comparing the same papers both before and after
the air filter may be interesting. Other than ozone levels, the environment should be identical
in both locations.
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