Some paper products are manufactured using acids or other chemicals that degrade or destroy the paper over time. Newsprint is a prime example of paper stock with a high acid content. It and any other materials with which it comes in contact over time can discolor and decompose. This means that any newsprint should be stored separately, so that it doesn't touch other documents. An excellent solution is to make a photocopy of any newspaper items and store the copy instead of the original.
Direct sunlight is a very real enemy to paper products.
The light and heat can cause the paper to age, fade, discolor, and deteriorate over time. Sunlight and bright light also interact with photographs of all types, causing them to fade and disintegrate. Moisture and humidity can do more damage than you might think. They certainly can damage the cellular structure of paper, causing it to warp, weaken, and deteriorate. They also provide an ideal environment for the formation of mold and mildew and create a breeding ground for a variety of insects and parasites.