Conservation and restoration of outdoor artworks
The conservation and restoration of outdoor artworks is the activity dedicated to the preservation and protection of artworks that are exhibited or permanently installed outside. These works may be made of wood, stone, ceramic material, plastic, bronze, copper, or any other number of materials and may or may not be painted. When applied to cultural heritage this activity is generally undertaken by a conservator-restorer. Environmental issues. Unlike many works of cultural heritage, outdoor artworks are not exhibited in a controlled environment, where temperature and relative humidity are closely monitored. Though works may be  more easily preserved in a controlled environment, they are installed outside to preserve the artist's intent, and avoid decontextualization. Instead, outdoor works are exposed to many and various environmental factors depending upon its geographic or site location and its configuration. Environmental threats may include, but are not limited to rain, snow, acid rain, and earthquakes as well as fluctuations in temperature and relative humidity. They may also be exposed to excessive amounts of light as well as human intervention. Excessive rain and moisture can also lead to mold growth. Daily exposure to ultraviolet, visible, and infrared (IR) radiation has  a detrimental effect on painted sculptures or those with organic or inorganic coatings. Excessive light exposure may cause color alterations and loss as well as structural breakdowns in the paint and coatings. Air pollution can also adversely affect outdoor artworks. In addition to meteorological conditions, traditional outdoor pollutants including sulfur dioxide, nitrogen oxides, and ozone affect the various composite materials. The specific level and type of air pollution degradation is dependent on the material and composition of the artwork as well as the length of exposure. Organic carbonyl pollutants are also an increasing threat due increased use of ethanol based  fuels. Contemporary conservation methods. Though specific conservation methods are dependent on the material, condition, and environment for each artwork, there are some standard practices for outdoor works. These include condition assessment, treatment, preventive conservation, and maintenance. Assessment of condition. Before any conservation treatment, a thorough condition assessment with written and photographic documentation is completed. This initial assessment may include research into the artist's working techniques or a discussion with the living artist, review of the conservation history of the object, and non-destructive analysis. According to Virginia Naudé and Glenn Wharton, there are four steps that come with the  assessment or survey of an outdoor sculpture: Treatment of outdoor artworks. The treatment of outdoor artworks is multifaceted and dependent on the material type, condition, structural integrity, and exhibition conditions. A brief overview of conservation treatments by material is outlined below, and more thorough discussions are available on the individual conservation pages. Preventive conservation. Preventive conservation involves actions taken to delay deterioration of cultural heritage. For outdoor artworks, this usually involves the application of a protective coating and regular maintenance. The particular protective coating is chosen based on its durability, adhesion to the surface, ease of maintenance, and surface appearance  on the work. The coating provides some protection from environmental factors, but must be occasionally be reduced and reapplied for best results. A long-term conservation schedule should be created and implemented to ensure the longevity of the artwork. A maintenance walk-through schedule should also be established to routinely check the condition of the objects. This may be a weekly procedure; it is useful as conservators can assess and document any damage caused by visitors or environmental conditions, and may rinse and wipe down sculptures. Tools and products. This section is an abbreviated list. For the detailed list, please  refer to the conservation and restoration of outdoor bronze sculptures.