Library and archive collections are a treasure trove of knowledge and culture, built from – paper, leather, canvas and natural glues. Unfortunately, for many insect species, these valuable objects are an ideal food source.
Pests such as the breadfruit beetle and the red-footed thief can secretly burrow tunnels into books, causing irreversible damage. So how can we effectively protect our heritage without exposing it to chemical or physical damage? The answer lies in science and the anoxic method.
What is the anoxic method?
The anoxic method, also known as the anaerobic method, is a modern and completely safe disinfestation process that involves the physical removal of oxygen from the environment of the infected object.
Instead of introducing toxic chemicals, a controlled atmosphere is created, most often filled with pure nitrogen. In such conditions, deprived of essential oxygen, pests in all stages of development inevitably die. It is therefore an intervention based on fundamental laws of biology, not aggressive chemistry.
Why is lack of oxygen deadly to insects?
The anoxic, or anaerobic, method is based on a fundamental principle of biology: Almost all organisms with a cell nucleus need oxygen to live. Insects, regardless of their stage of development, are no exception. Oxygen is a key fuel for them in the production of cellular energy (ATP), which powers all life functions.
When we place an infected object in a sealed chamber and replace the standard air (containing about 21% oxygen) with an inert gas such as nitrogen, a cascade begins in the pest's body leading to its death:
- Stopping the energy “engine”: Without oxygen, insect cells lose their primary energy source. Their highly efficient aerobic metabolism is immediately halted.
- Survival Test: The insect tries to save itself by switching to an extremely inefficient anaerobic metabolism and drastically slowing down its vital functions, often entering a state of paralysis or coma.
- Reserves exhausted: Despite these defense mechanisms, the limited energy reserves stored in the insect's body are inevitably consumed. When these levels fall below a critical threshold, cells begin to die.
Why does the process have to take 3-4 weeks?
The answer lies in the varying resistances of each developmental stage. Adults and active larvae die relatively quickly because they expend so much energy. However, the eggs and pupae pose the greatest challenge. These spore forms have an extremely slow metabolism and minimal energy requirements.
Długi czas trwania zabiegu (standardowo 21-25 dni) jest skalkulowany właśnie po to, by mieć 100% pewność, że nawet te najbardziej odporne formy życia ostatecznie „wypalą swoje paliwo” i zostaną bezpowrotnie wyeliminowane. To gwarantuje, że po zakończeniu procesu populacja szkodników się nie odrodzi.
Why is nitrogen neutral to crops?
The greatest advantage of the anoxic method is its complete safety for the objects. This is not a coincidence, but the result of fundamental laws of chemistry. Nitrogen (N₂), which makes up 78% of the air we breathe, is an extremely stable and chemically inert gas.
The atoms in the nitrogen molecule are connected by a very strong triple bond, which requires enormous energy to break. Under the conditions prevailing during pest control, nitrogen simply does not react chemically with the materials from which books and documents are composed.
- Paper and canvas (cellulose): Nitrogen does not cause yellowing, embrittlement, or any other form of degradation. Furthermore, the removal of oxygen from the environment actively inhibits the paper's natural aging processes (oxidation) for the duration of the treatment.
- Skin and parchment (collagen): The protein structure of these materials remains intact, retaining its flexibility and strength.
- Adhesives, paints and pigments: Nitrogen does not affect their chemical composition and does not cause color changes or fading.
The anoxic method in practice
Today, the anaerobic pest control process is fully automated and safe. Infected objects are placed in a special, gas-tight chamber constructed of barrier foil. Then, using a generator, the air is forced out and replaced with pure nitrogen.
Thanks to solutions such as the nitrogen generator OxygenFree od An2Di, this advanced conservation technology is becoming available to every institution. It enables independent, safe, and environmentally friendly pest control on-site, without the need for external contractors and without the use of any toxic chemicals. This is the gold standard in the ethical protection of priceless cultural heritage.