Museums

Historic archives and treasures stored and/or on display in museums, galleries and libraries are extremely sensitive to particulate and molecular pollution as well as changes in temperature, relative humidity, sunlight and interior lighting. As temperature and relative humidity increase a synergistic relationship can exist with molecular contaminants in the air which can accelerate the rate of artefact degradation. Both the concentration dosage and the exposure time have an effect on the rate of degradation. The greater the concentration and exposure time – the greater the damage potential to works of art.

AAF offers an integration solution of particulate and molecular filters to improve IAQ, eliminate odours and achieve energy savings and reduce Green House Gas (GHG) emissions.

Molecular Contaminants
Outside air that is brought into a building via a ventilation system in a controlled way or naturally in an uncontrolled way will always contain certain amounts of particulate and molecular contaminants. Molecular pollution can originate from natural processes and/or manmade activity:
Natural: volcanic eruptions, evaporating hot springs etc
Manmade: combustion of fossil fuels and industrial processes like exhaust gases from vehicles, power plants etc

Damage to precious artefacts are usually caused by two main categories of molecular contaminant:
- those with acidic chemical properties
- those with oxidising chemical properties

The table below shows sources and effects of molecular contaminants on various artefacts.

Particulate Contamination
Like molecular contamination, particulate matter emanates from a wide variety of natural and manmade processes. Typical examples of manmade particulate include those produced by vehicle exhaust fumes, cigarette smoke, industrial combustion processes, emissions from building construction materials and various other human activities. Naturally occurring sources include volcanic eruptions, desert storms, sea spray and the like.

Particulate matter can cause significant damage to works of art. Large, heavy particulates, with a high metallic content, can scratch and deface materials when they settle on surfaces. Light, small particulates can migrate to the most remote corners of a room or space, resulting in soiling and discolouration of precious artefacts like frescoes and paintings.

Particulate matter produced by the combustion of fossil fuels is often oily and/or sooty by nature and have acidic properties that cause acidic corrosion on valuable artefacts. Particulate produced as a result of building construction materials like concrete have alkaline and abrasive properties which can scratch and/or deface frescoes, oil paintings, tapestries and other textile fabrics.

Applications
In the main buildings of museums, archives and galleries molecular filters can be used in the fresh make up air, supply air or recirculation air units. The type and combination of products depends on various factors:
- the types and concentrations of gaseous contaminants
- airflow parameters
- required media service life
- characteristics of the air handling unit e.g. space availability

In addition, there are other locations within or close to the main display and storage areas where molecular filters can be applied e.g. cafeterias, restaurants, offices and restoration and conservation laboratories.