Dust is one of the most ubiquitous substances in the workplace, and nearly impossible to eradicate entirely. It can cause a range of problems to objects and collections, depending on its nature. The Preventive Conservation team in Collection Care work across all areas of the library putting measures in place to protect the collections from harm, to inhibit the progress of existing damage/deterioration, and to prevent new damage from occurring. The team are continually working to monitor and establish the causes of high and low dust levels to protect our collections.

Figure 1: High shelf surfaces can experience severe dust build-up if not regularly cleaned.

What is dust?

Dust is a fine dry powder made up of tiny particles of earth or waste matter. It comes from a variety of sources including textile fibres, flakes of shed human skin and hair, pollution particulates, dead insect body parts, insect excrement, building materials (such as fragments of plaster, concrete and paint), soil carried on shoes, and pollen. If a collection item is sufficiently deteriorated then it can generate its own dust as it crumbles away. Lighter particles are capable of being airborne while heavier particles tend to remain in low-lying areas where they are first deposited. Airborne dust is more likely to be a problem in collections as it has a greater likelihood of being deposited on objects and shelves above floor level. It may also be readily spread by air conditioning systems.

Figure 2: Dust can gather on top of books and between bindings if neglected. Problems relating to dust go beyond aesthetics. 

Dust build up is affected by cleaning and housekeeping practises, room layouts and shelving location, human traffic patterns, air circulation, types of shelving and the type and condition of the books. Areas with a lot of human activity such as busy working areas or queues for reading rooms or photocopiers have been found to contain the most dust.

Problems caused by dust

The Preventive Conservation team closely monitors the type of dust as this may affect damage. Dust particles can act as an abrasive causing surface damage when objects are moved or subjected to mechanical cleaning. Building work may produce corrosive dust that needs to be cleaned quickly. Some types of dust particles may be alkaline or acidic promoting hydrolytic damage, especially if the surface is already damaged by abrasion. Dust which contains small amounts of plant pollen can worsen hay fever for anyone working or visiting at the library. Mould spores and pests which can attack collection items feed on dust particles. The house dust mite (Dermatophagoides pteronyssinus) who feeds on organic detritus material is ubiquitous in places that humans occupy.

Figure 3: The house dust mite, Dermatophagoides pteronyssinus, feeds on particles already partially decomposed by fungi. 

Dust mites are arachnids, not insects, and they cannot control their body temperature. This means that the length of their life cycle varies with the temperature of their habitat. A female adult with a life cycle of about 4-6 weeks can produce 40-80 eggs. They produce about 2,000 fecal particles and even more partially digested enzyme-covered dust particles! Dust can also act as a respiratory irritant. Many people suffering with asthma have dust mite allergies which make dust control a health and safety issue.

Dust monitoring

Dust monitoring is part of the work carried out by the Preventative Conservation team. Dust can be monitored by visual inspection, long-term study, dust analysis (microscopy, spectroscopy), and instrumental methods such as laser light scattering. For most situations, the more sophisticated analytical methods are unnecessary – a simple visual inspection is generally adequate.

Cleaning helps alleviate the potential for dust to cause damage to collections. Methods of cleaning must be chosen to be appropriate both to the object and the type of dust.

Figure 4: If you can write your name on surfaces, it’s probably time for a clean!

The effects of dust can be reduced by moving items in high risk areas, changing shelving types, or boxing items. Static shelving (especially close to working areas) is much dustier than mobile shelving which may encourage some fall-out of dust from canopies preventing build-up. It is difficult to protect collections entirely from dust, especially as high value items are in busy areas due to high reader demand. Boxing of material is only practical for single items or small collection items with special needs.

Balancing benefits and risks

Any changes to minimise dust should not increase risks to the collections from other factors. Care must be taken that the additional handling of the books whilst cleaning, and the danger of dust particles acting as an abrasive during mechanical removal, does not cause more damage than it prevents. For example rearranging books or shelving should not result in collections becoming more vulnerable to theft, or making retrieval more difficult or inconvenient. Similarly, altering air flow patterns should not raise relative humidity and/or temperatures which may encourage mould and pests.

Contact the Preservation Advisory Centre for advice on dust monitoring and dust surveys. Make sure you read our free to download booklet on cleaning books and documents for the best way to approach a cleaning plan.

More reading: Dust mites by Matthew J Colloff, CSIRO Entomology publishing. Informazione Medica Pazienti: Advice for patients allergic to dust mites.

Christina Duffy (@DuffyChristina)