The Effects of Hydrogen Sulfide, VOCs and Bioaerosols on People with Mitochondrial Disease

2 Sep, 2026

Written by Paula Morandi, Chair of IMP

Why emissions from olive‑pomace fermentation pose a serious health risk

The open‑air fermentation of olive pomace (the waste product of olive oil production) produces a range of volatile emissions through anaerobic and aerobic microbiological processes. Among these, hydrogen sulfide (H₂S) is the most direct and well‑documented physiological threat, particularly for people living with mitochondrial disease.

Photo showing olive oil being poured from a glass bottle

How These Emissions Affect Mitochondrial Function

1. Hydrogen Sulfide (H₂S) Toxicity

Direct inhibition of Complex IV: H₂S blocks cytochrome c oxidase, a critical enzyme in the mitochondrial respiratory chain.
Amplified harm in mitochondrial disease: Healthy mitochondria can detoxify small amounts of H₂S via the enzyme SQR. In people with mitochondrial disorders — including Complex I, III or IV deficiencies, Leigh syndrome or MELAS — this protective capacity is already compromised. Even low‑level or prolonged exposure can further reduce ATP production, increase oxidative stress and trigger muscle or neurological symptoms.

2. Volatile Organic Compounds (VOCs) and Bioaerosols

VOCs (fatty acids, aldehydes) can cause respiratory irritation, systemic inflammation and increased metabolic strain, placing additional energy demands on already fragile mitochondrial systems.
Bioaerosols (fungal spores, bacteria) may provoke immune responses or respiratory infections. For mitochondrial patients, infections and fever are major triggers for acute metabolic decompensation and mitochondrial crises.

Reducing Exposure: Practical Mitigation Measures

At the Source

Covering storage piles or moving pomace into enclosed, ventilated facilities.
Using biofiltration or activated‑carbon systems to reduce H₂S and odorous compounds.
Shortening storage times to limit fermentation and oxygen‑depleted conditions.

For Individuals and Communities

Maintaining adequate distance from emission sites, considering wind direction.
Using indoor air purification with HEPA filters (bioaerosols) and activated carbon (VOCs and sulfur gases).
Wearing appropriate respiratory protection outdoors when avoidance is not possible.

Medical Guidance

For anyone with a confirmed mitochondrial disease, environmental exposure to substances that impair mitochondrial function should be strictly avoided. It is essential to inform a treating specialist or clinical geneticist so that appropriate environmental and public‑health protections can be assessed with local authorities (such as ASL/ARPA in Italy or equivalent agencies elsewhere).

Why This Article Matters

In many countries, waste‑management practices are under scrutiny. In Italy, the recent construction of a biodigester has raised significant concern due to strong odours from open‑air olive‑pomace fermentation. After reviewing the scientific evidence with mitochondrial experts, the conclusion is clear: these emissions pose a serious risk not only to mitochondrial patients, but to the wider community.

Paula Morandi