Yes.
Light damages books, and UV-light especially so.
That makes the idea of using UV rays for sterilisation of books quite stupid.
And 'in light' of recent viral infections panics, simple 'quarantine' of books will render the theoretical danger of the unproven fomite route harmless. These viruses don't 'survivie' long on paper since they 'dry out' in a short time, and seem to be not capable of infection via that route anyway. Just let the books sit around for while…
- Use copies whenever possible.
- Do not display a valuable paper artifact permanently.
- Keep light levels as low as possible.
- Minimize exposure to ultraviolet light with appropriate filters.
- Insure that cases and frames are enclosed, sealed, and made of materials that will not damage their contents.
Light
Light can be a serious problem for objects on display. Paper is one of the most light sensitive materials, as are certain other writing and drawing media. Light can cause darkening of paper and fading of media and book covers. Damage by light goes beyond visual alteration by attacking the physical structure of paper, causing weakening and embrittlement. Light also damages the emulsions of photographs.
All light is damaging. The higher the light levels, the greater the potential danger. Sources rich in ultraviolet (UV) radiation are especially hazardous. Because light damage is cumulative, even low levels can degrade paper if the exposure is long enough. Conservators therefore recommend that no valuable artifact be permanently displayed.
Natural Light (Daylight) Is Especially Harmful
Exposure to natural light is undesirable because of its intensity and high UV content. If there are windows in the exhibit area, they should be covered with blinds, shades, or curtains for as much of the day as possible. In addition, ultraviolet filters should also be installed to control this damaging component of light.
— "Protecting Paper and Book Collections During Exhibition"
Mary Todd Glaser
Director of Paper Conservation
Northeast Document Conservation Center (PDF)
Another take:
Light.
Sunlight, incandescent and fluorescent light are sources of ultraviolet (UV) radiation. The UV rays in sunlight and fluorescent light can cause rapid fading in colors and inks and brittleness. Any strong light source may cause paper to fade, even if the light has been filtered with UV shields. However, very low light levels plus high humidity can result in mold growth.
Several months of exposure to even very low light levels may have the same effects on paper as a few days of direct sunlight. Damage by light is not reversible.
Storing book collections and other paper items in the dark may not be practical. Suitable precautions may include storage out of direct sunlight, use of special UV filtering shields on windows and lights, and use of heavy draperies. Valuable papers, such as old deeds, diplomas, etc. can be kept in acid-free file folders in low light areas.
— Shirley Niemeyer: "Preservation of Paper Items", Historical Materials from University of Nebraska-Lincoln Extension, 1994. NF94-138 (PDF)
In numbers:
According to book and archive preservationists, old books and documents deal with three great enemies, who harm them, and many times destroy them2. These enemies are dust, biological damage and light.
Finally, the third and greatest enemy is the light and the damage it causes […] we will see them turn yellow and then start to crumble. Today, modern pulp contains cellulose, which is the raw material for making paper. Cellulose is a macromolecule and light has the ability to break it down, thereby dissolving the base of the paper.
However, the danger is not only the electric light but also the sun. Light accelerates degradation of archival and library material, causing photochemical reactions of oxidation and depolymerization of cellulose (Feller, 1994, Havermans & Dufour, 1997, Forsskahl, 2000). At the same time, it activates the cycle of photochemical reactions in space, which will lead to the creation of hazardous pollutants for the materials of the collections. It causes paper to fade and causes color changes (bleaching or yellowing). It can also cause fading or discoloration of pigments and inks, reducing readability and altering the appearance of documents, photos, artwork and bookbinding.
Any exposure to light, even of short duration, is harmful, and the damage caused is cumulative and irreversible (Glaser, 1999). Although all wavelengths are harmful, the ultraviolet part of the spectrum (UV light below 415 nm) is the most destructive for archival and bibliographic material due to its high energy content. Ultraviolet radiation limit for archives and libraries is 75 μw / lux4 (Glaser, 1999, ISO 11799, 20033). The sun and halogen and fluorescent lamps are the most destructive sources of light because they emit large amounts of ultraviolet radiation. Material protection measures focus on excluding harmful radiation (DenTeuling, 1996, Glaser, 1999, Ogden, 1999b, Patkus, 1999c, ISO 11799, 2003). Windows should be covered with heavy curtains and shutters so that sunlight can be completely prevented from penetrating storage areas.
— Marina Nikta: "The Need to Keep Books, Archives and Rare Documents "Alive"", Qualitative and Quantitative Methods in Libraries (QQML) 8,2: 209–220, 2019. (PDF)
When done in an experimental setting with different lasers, the effect might be quantified easier. UV-light is much more and immediately damaging papers. It seems that cheaper paper is also much easier to damage:
The change of the degree of polymerisation (DP) of Whatman filter paper and sulphate pulp (Sa) after laser treatment at three different wavelenghths is presented in Fig. 2. The 308-nm radiation of the excimer laser causes an immediate depolymerisation of Whatman paper, and particularly of sulphate pulp, where the DP decreased by almost 31%.
This may be caused by the high energy of the incident light. Absorption of photons with energies greater than ≈ 3.6 eV(λ < 340 nm) can lead to direct photolysis, or can induce photo-oxidative degradation of cellulose. A marked difference in the extent of degradation of the Whatman paper (purified cotton cellulose) and sulphate pulp may be ascribed to the fact that pure cellulose is an extremely poor absorber of UV light of wavelength greater than 200nm. Carbonyl or acetal groups are the most likely species responsible for the weak absorption in this region. Sulphate pulp, on the other hand, contains several non-cellulosic impurities (metal ions, lignins) which may induce sensitised photodegradation of cellulose, thus resulting in severe depolymerisation. Additionally, a higher crystallinity of cotton cellulose (Whatman) as compared to that of the sulphate pulp may also contribute to the higher stability of the former sample, as the photochemical reactions in cellulose occur predominantly in amorphous regions of the polymer structure.
Extensive photodegradation during irradiation with UV photons is likely to be accompanied by formation of reactive radicals and oxidised species, which may subsequently, through radical chain reactions, impair the ageing stability of the material. This effect is observed for Whatman paper, where the DP of the untreated reference sample decreases by 6.2% during the 6 days ageing period, whereas the change is between − 7.4% and − 9.2% for laser-treated samples. The effect is less pronounced in the case of Sa pulp, where the differences are within standard deviation (Fig. 3).
Fig. 2. Change of degree of polymerisation (DP) during treatment of Whatman and sulphate (Sa) pulp with laser radiation at 308 nm, 532 nm, 1064 nm and fluences less than 2.5 J cm−2
— J. Kolar, M. Strlic, S. Pentzien, W. Kautek: "Near-UV, visible and IR pulsed laser light interaction with cellulose", Applied Physics A
Materials Science & Processing, p87–90 (2000). (DOI: 10.1007/s003390000491) (PDF)
Naturally occurring UV and visible light is described as 'extremely bad' for paper and ink. In practice this damage shows up only over time. But compared to a machine designed for disinfection the energy level delivered in such an artificial aging machine is of course a few degrees higher and thus the damage appears much faster.
This may be weighed against the cumulative damages caused by any type of irradiation. The trade-off between damaging of public goods and a mindless 'desinfection' to combat virus hysteria may appear to 'work' for a while under certain conditions. Take note of the organisational affiliation of this author and that this small study was not conducted to look at any viruses but already damaged papers that were subject to real biological organisms:
The results obtained can be explained considering that the applied dose, calculated in excess of the dose required to eliminate mould and arthropods, proved too low to produce chain ruptures in cellulose polymers to a degree that could affect substantially the mechanical properties of the papers. In fact, important decreases of the degree of polymerisation may not be reflected on the mechanical properties. It has been reported that a decrease of 58% of the degree of polymerisation of Whatman No 1 paper did not change appreciably the mechanical properties (Calvini and Santucci, 1978–79) and even a decrease of 76% did not affect the mechanical properties (Phillips and Arthur, 1985).
Besides, the irradiation time was short, so the possibilities of oxidative degradation induced by radiation were also limited.
On the other hand, the test for accelerated ageing, in which the papers were subjected to UV radiation in the presence of oxygen for a long time showed the effect irradiation process at very low dose-rate would have on The damage in mechanical properties originated by accelerated ageing was much larger than that induced by gamma irradiation.
Irradiated and control samples experienced similar damage when subjected to accelerated ageing.
Mould contaminated paper maintained its mechanical properties after irradiation.
No colour changes were observed after irradiation and/or ageing.
— Eulogia Kairiyama, Comision Nacional de Energía Atómica, Argentina: "Gamma radiation for preservation of biologically damaged paper"
Radiation Physics and Chemistry 63 (2002) p263–265 DOI: 10.1016/S0969-806X(01)00510-2 (PDF)
In the context of infectious viral diseases the WHO recommendations are useful that state for effectiveness of UV-lights during pandemics:
"UV light is Not recommended in any circumstances".
— WHO: "Non-pharmaceutical public health measures for mitigating the risk and impact of epidemic and pandemic influenza", World Health Organization, Global Influenza Programme, 2019. p3 PDF
For completeness of a likely tangential for this question: A big caveat towards how effective the proposed mechanism using UV-light might be. In short, we know any virus will also be damaged somehow by UV-light, but in case of for example SARS-CoV2, the knowledge is inconsistent as of yet. Meaning: to be 'safe' (and that is: in clinical settings) the dosage likely required would have to be quite high. Data is only available for SARS1, and completely missing for efficacy on books as a medium. UV is no '(colloidal) silver bullet':
- Ultraviolet light C (UVC) applied doses varied markedly from 300 to 14,500 mJ/cm2, with mixed outcomes.
- At 360 mJ/cm2, SARS-CoV-1 had the highest UV D90 (i.e. required applied dose for 90% inactivation) among nearly 130 viruses from hundreds of published studies summarized by Kowalski. In addition, in protein medium, an applied dose of 14,500 mJ/cm2 did not completely inactivate the virus, due to competitive absorption of UV photons by the protein.
- UVC is effective against SARS-CoV-1, but efficacy of the applied dose (a function of irradiance and time) appears to be highly dependent on many factors, such as inoculum size, culture medium, and shape and type of material likely explaining the highly inconsistent findings in the published literature.
3.1. Ultraviolet germicidal irradiation (UVGI)
Across the ultraviolet (UV) light spectrum, there are three classifications: UVA (320-400 nm), UVB (280-320 nm), and UVC (200-280 nm). UVC light has much stronger germicidal properties than both UVA and UVB. UVC is strongly absorbed by RNA and DNA bases leading to molecular structural damage via a photodimerization process. This results in virus inactivation, such that they are no longer able to replicate. Thus, the focus of this protocol has been on UVC.
- Studies were found only for SARS-CoV-1. It should be noted that those studies were almost invariably performed on aqueous solutions, in air, or on solid surfaces, i.e. environments that do not directly reflect for example, the micro-environment of N95 FFRs. As a result, the reported applied doses are at best a relative guidance.
- Ultraviolet light C (UVC) applied doses varied markedly from 300 to 14,500 mJ/cm2, with mixed outcomes.
- At 360 mJ/cm2, SARS-CoV-1 had the highest UV D90 (i.e. required applied dose for 90% inactivation) among nearly 130 viruses from hundreds of published studies summarized by Kowalski. In addition, in protein medium, an applied dose of 14,500 mJ/cm2 did not completely inactivate the virus18 (Table 2), due to competitive absorption of UV photons by the protein.
- UVC is effective against SARS-CoV-1, but efficacy of the applied dose (a function of irradiance and time) appears to be highly dependent on many factors, such as inoculum size, culture medium, and shape and type of material, likely explaining the highly inconsistent findings in the published literature.
- Based on the available evidence it seems that the effect of relative humidity on UVGI efficacy can be considered negligible.
- Importantly, the applied dose is not necessarily the same as the actual dose the treated virus receives. While the applied dose is easy to measure experimentally, the received dose is not. If there are shadowing or absorption effects from the surrounding medium, the actual dose reaching the virus will be lower.
- The penetration of UV across the multiple layers of an N95 FFR may vary from one model and manufacturer to another25. There is some limited evidence that the majority (approximately 90%) of captured aerosols occurs on the outer filter layer on an N95 FFR26. Therefore, providing a larger UV dose on the outside surface may be desirable.
- Overall, the effective applied dose is unclear, but appears to be high in comparison to other viruses.
- Mills et al. (2018) reported on a more extensive set of tests on N95 masks using H1N1 viruses, and included the effects of soiling agents (artificial saliva and/or skin oil) that could reduce the efficacy of UV exposure. Fifteen different N95 models were tested from a variety of manufacturers, and both the facemask and straps were monitored. All FFRs were disinfected to a level of at least 3 log (i.e. 99.9%), even in the presence of soiling agents, when the UV dose was 1,000 mJ/cm2. Similarly, Heimbuch & Harnish (2019) showed complete disinfection of SARS-CoV-1 from FFR coupons in the presence of artificial saliva (mucin) and artificial skin oil (sebum).
- We estimate that the minimum applied UVC dose for effective deactivation of SARS-CoV-2 on N95 FFRs would likely be close to 1,000 mJ/cm2, particularly in light of the mask’s porous surface (as compared to a smooth surface material), as shown by Heimbuch & Harnish's 2019 study.
- Note that the studies showing SARS-CoV-1 survival at higher doses were most likely confounded by the aqueous media (often with added protein), which would absorb UVC photons, reducing the actual dose reaching the virus.
3.3. Disinfection summary
The applied UVC dose should be at least 1,000 mJ/cm2, but we recommend an initial conservative dose of 2,000 mJ/cm2 [applied to each side of N95 FFRs, i.e. wearer-facing and outer sides] to account for possible errors in applied dose estimation, effects of different materials, the challenge to reach the inner filtering layers of FFRs25, as well as the uncertainty regarding the actual susceptibility of SARS-CoV-2 to UVGI.[…]
We advise against attempts to disinfect and reuse soiled PPE, as studies using both UVGI and heat treatment show a protective effect of protein and aqueous substrata on SARS-CoV-1 survival.
- Unpublished experimental data from our group showed that there is minimal UVC radiation on the wearer-facing side of N95 FFRs when the outer side is irradiated (outer 7.34 mW/cm2 vs inner 0.10 mW/cm2). There are reports of widespread SARS-CoV-2 infection among frontline medical staff, thus, it has to be assumed that SARS-CoV-2 contamination of N95 FFRs would likely occur on both sides, particularly when there is strong evidence of asymptomatic transmission. Therefore, we strongly recommend that both wearer-facing and outer sides of N95 masks be equally treated at the recommended UVC dose.
— José G B Derraik et al.: "Rapid evidence summary on SARS-CoV-2 survivorship and disinfection, and a reusable PPE protocol using a double-hit process", medRxiv preprint doi: https://doi.org/10.1101/2020.04.02.20051409.t, 6 April, 2020.
So there is no evidence for that machine killing any new-fangled virus with its 'UV light'. The amount of UV to inactivate SARS is much higher than for other viruses. UV light needs to reach every nook and cranny that might be contaminated to clear out everything. Theoretically, that machine just uses a peculiar method by which it is claimed this would be achieved:
In addition to the UV light, this machine also has fan. The fan is used to make sure that the pages are spread wide enough that all are exposed to the light and it also blows a mild perfume onto the books. The change in smell is said to calm readers and reassure them that the book was clean.
— Nate Hoffelder: "A New Solution for Dirty Books: a UV Sterilization Machine", The Digital Reader, 2 March, 2014.
It makes patrons feel safe. This would have to be classified as a complete bogus pipeline. But then there is this perfume…
