Musty Smell In My Camper

What you want is called an ozone generator...Here's some plans I found, you can adapt them as you see fit...

" First you need a neon sign or similar transformer at about 6000v. You need
a small glass jar and a larger jar that will hold the smaller one.The
larger jar can be glass or plastic, I have successfully used a plastic cup
for the larger jar but the smaller one should be glass.
Lastly you need a small amount of aluminum foil and you may need a few
short pieces of wire. The transformer can be as small as 3000v but the more
the better up to a point. I use 7000v and that is plenty but you can use up
to 15000v.

Put a small piece of aluminum foil (about 2" sq.) inside the small jar at
the bottom. Cover the outside bottom of the small jar with foil so that it
covers the same area as the foil inside. You can cover the whole inside and
outside of the jar, that may work better but just make sure the inner and
outer foil layers do not touch or come too close. Put the smaller jar
inside the larger one. Connect one high voltage lead to the foil inside and
the other to the foil outside. The larger jar just insulates the whole
thing. I would put the whole set up on a piece of wood or other insulator.
Try not to cross the wires. The bare part of the wire must touch the foil.
If the insulation on the wire makes it difficult or if the wires are too
short, you may use some other wire to extend them. Be sure to keep the
wires as short as possible you don't want to touch them they will give you
a jolt. Turn it on, you'll hear acrackling noise and if its dark you'll
see a blue glow. If theres a short you may see an arc, just turn it off and
separate the conductors so that they don't short out. The ozone will come
out the top so don't plug it up. Ozone is a very powerful deodorizor it
also tends to kill mold and bacteria..."

"...I think I would set up the ozone generator a little differently.First, I would scrap the

glass jar thing and use a small piece of glass with equal sizes of wire mesh mounted on both sides (these are called glass plates).My store-bought one mounted the wire mesh onto the glass with clear silicone caulking.I would mount the whole deal inside a wooden box (for safety reasons) with a top and two sides.I would mount a small computer type fan one one of the open sides to blow the ozone out. Finally, I would install some sort of dimmer switch to regulate the ozone output."

http://www.cannabase.com/cl/bcga/bcga/ozone.htm

I don't know if an ionizer is going to do much good beyond temporarily cleaning the air.

The musty smell is likely coming from mildew that has taken root due to the moisture. Find and eliminate the mildew, and the musty smell will dissipate on it's own. Not a fun job, but mildew can even be quite dangerous to breath.

http://www.livestrong.com/article/17223-signs-mold-sickness/

If there is insulation between the interior ceiling and the roof, that is likely to be the area where the mold/mildew is growing, as well as any walls, etc., that became wet from the roof leak. Simply drying it out won't do the trick. Insulation should be removed and replaced, and any other surfaces like paneling can be treated with a bleach solution, wiped clean, dried and put back.

I think this may be the simple way to do the job. There are companies that rid motel rooms and other places of bed bugs. They heat the interior of the room to 180 degrees. This kills every living organism including the mold that is making the musty smell. My suggestion is to find one of those companies and have them treat your vacation trailer. OH! don't forget to take anything out of the trailer that you don't want to harm, like candles and your wife.