Why CO₂ levels rise in sealed grain storage environments
In a hermetically sealed environment, CO₂ levels can rise for a number of reasons, depending on the context. Here are the main explanations, classified by cause:
Grain respiration
Wet grain releases CO₂ mainly due to its cellular respiration.
Even after harvesting, grains remain alive if they still contain moisture (generally > 14%). This moisture enables enzymatic and metabolic activity, which means that the grains continue to breathe:
Glucose (C₆H₁₂O₆)+O₂→CO₂+H₂O+energy
This leads to oxygen consumption (O₂) and CO₂ production → O₂-depleted, CO₂-enriched atmosphere.
The higher the humidity, the more intense the respiration. If the temperature rises, this further accelerates CO₂ production.
Insects and micro-organisms respiration
The presence of living organisms (insects, fungi, bacteria, micro-organisms) inside the sealed volume also contributes to the emission of CO₂ through respiration, fermentation or decomposition.
Outgassing of materials or substrates
Some organic materials or substrates (such as wet grains or organic residues) can release CO₂ stored or formed during chemical degradation.
Internal chemical reactions
In rare cases, chemical reactions (e.g. with carbonates or unstable organic compounds) may generate CO₂ in the presence of moisture or acidity.