The Environmental Sensitivities Cycle

Increasingly, scientists are identifying a two-phase process leading to environmental sensitivities.

Phase 1: Onset of the illness

The onset of the illness takes place either after chronic low-level exposure to contaminants or after one high-level exposure to a chemical substance, electromagnetic radiation, or a biological agent. The factors involved are called initiating agents (Table 1).

The most common initiating agents of the illness are:

  • Pesticides ƒ
  • Volatile organic compounds (VOCs: solvents, perfumes, formaldehyde and other petrochemical products, exhaust gases from vehicles) ƒ
  • Moulds ƒ
  • Electromagnetic radiation and/or fields

These agents can emanate from the structure of a building, some types of furniture and equipment, neighbourhood surroundings, cleaning products, etc. There are also environmental factors which can worsen the symptoms of environmental sensitivities such as lighting, humidity, heat, cold and noise.

The initiating agents cause a loss of tolerance in affected people, thereby triggering the environmental sensitivities cycle.

Phase 2: Manifestation of the illness

Once environmental sensitivities are triggered, people who are affected often react to several other triggering agents (Table 1), even at very low doses or concentrations. A series of metabolic reactions then brings about many symptoms (figure 1), resulting in a chronic condition.

phase ES

Share you resources!

Persons suffering from environmental sensitivities generally have a vast amount of information as far as the resources available in the region.
Do you know understanding professionals who are aware of ES and can provide accommodation? The best places to buy healthy products or where to get services? Why not share your information?


UQAM - service au collectivitésTELUQ
Association pour la santé environnementale du Québec
Logo-Quebec invWith the financial support of the Ministry
of Education, Recreation and Sports (Québec)

Translation from French to English has been made possible in part by the Department of Canadian Heritage and ASEQ-EHAQgovcan-e-col