be needed for further preservation and potentially conservation. Storage environment Environmental controls are necessary to facilitate the preservation of organic materials and are especially important to monitor in rare and special collections. Key environmental factors to watch include temperature, relative humidity, pests, pollutants, and light exposure. In general, the lower the temperature is, the better it is for the collection. However, since books and other materials are often housed in areas with people, a compromise must be struck to accommodate human comfort. A reasonable temperature to accomplish both goals is 65–68˚F (18–20 °C) however, if possible, film and photography collections should be kept in a segregated area at 55 ˚F (13 °C). Books and other materials take up and give off moisture making them sensitive to relative humidity. Very high humidity encourages mold growth and insect infestations. Low humidity causes materials to lose their flexibility. Fluctuations in relative humidity are more damaging than a constant humidity in the middle or low range. Generally, the relative humidity should be between 30–50% with as little variation as possible, however recommendations on specific levels to maintain vary depending on the type of material, i.e. paper-based, film, etc. A specialized dew point calculator for book preservation is available. Pests, such as insects and vermin, eat and destroy paper and the adhesive that secures book bindings. Food and drink in libraries, archives, and museums can increase the attraction of pests. An Integrated Pest Management system is one way to control pests in libraries. Particulate and gaseous pollutants, such as soot, ozone, sulfur dioxide, oxides of nitrogen, can cause dust, soiling, and irreversible molecular damage to materials. Pollutants are exceedingly small and not easily detectable or removable. A special filtration system in the building's HVAC is a helpful defense. Exposure to light also has a significant effect on materials. It is not only the light visible to humans that can cause damage, but also ultraviolet light and infrared radiation. Measured in lux or the amount of lumens/m2, the generally accepted level of illumination with sensitive materials is limited to 50 lux per day. Materials receiving more lux than recommended can be placed in dark storage periodically to prolong the original appearance of the object. Recent concerns about the impact of climate change on the management of cultural heritage objects as well as the historic environment has prompted research efforts to investigate alternative climate control methods and